src/third_party/WebKit/Source/core/rendering/RenderBox.cpp

   1 /*
   2  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
   3  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
   4  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
   5  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
   6  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
   7  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Library General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Library General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Library General Public License
  20  * along with this library; see the file COPYING.LIB.  If not, write to
  21  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  22  * Boston, MA 02110-1301, USA.
  23  *
  24  */
  25
  26 #include "config.h"
  27 #include "core/rendering/RenderBox.h"
  28
  29 #include "core/HTMLNames.h"
  30 #include "core/dom/Document.h"
  31 #include "core/editing/htmlediting.h"
  32 #include "core/frame/FrameHost.h"
  33 #include "core/frame/FrameView.h"
  34 #include "core/frame/LocalFrame.h"
  35 #include "core/frame/PinchViewport.h"
  36 #include "core/frame/Settings.h"
  37 #include "core/html/HTMLElement.h"
  38 #include "core/html/HTMLFrameElementBase.h"
  39 #include "core/html/HTMLFrameOwnerElement.h"
  40 #include "core/page/AutoscrollController.h"
  41 #include "core/page/EventHandler.h"
  42 #include "core/page/Page.h"
  43 #include "core/rendering/HitTestResult.h"
  44 #include "core/rendering/PaintInfo.h"
  45 #include "core/rendering/RenderDeprecatedFlexibleBox.h"
  46 #include "core/rendering/RenderFlexibleBox.h"
  47 #include "core/rendering/RenderGeometryMap.h"
  48 #include "core/rendering/RenderGrid.h"
  49 #include "core/rendering/RenderInline.h"
  50 #include "core/rendering/RenderLayer.h"
  51 #include "core/rendering/RenderListBox.h"
  52 #include "core/rendering/RenderListMarker.h"
  53 #include "core/rendering/RenderTableCell.h"
  54 #include "core/rendering/RenderTheme.h"
  55 #include "core/rendering/RenderView.h"
  56 #include "core/rendering/compositing/RenderLayerCompositor.h"
  57 #include "platform/LengthFunctions.h"
  58 #include "platform/geometry/FloatQuad.h"
  59 #include "platform/geometry/TransformState.h"
  60 #include "platform/graphics/GraphicsContextStateSaver.h"
  61 #include <algorithm>
  62 #include <math.h>
  63
  64 using namespace std;
  65
  66 namespace WebCore {
  67
  68 using namespace HTMLNames;
  69
  70 // Used by flexible boxes when flexing this element and by table cells.
  71 typedef WTF::HashMap<const RenderBox*, LayoutUnit> OverrideSizeMap;
  72
  73 // Used by grid elements to properly size their grid items.
  74 // FIXME: Move these into RenderBoxRareData.
  75 static OverrideSizeMap* gOverrideContainingBlockLogicalHeightMap = 0;
  76 static OverrideSizeMap* gOverrideContainingBlockLogicalWidthMap = 0;
  77
  78
  79 // Size of border belt for autoscroll. When mouse pointer in border belt,
  80 // autoscroll is started.
  81 static const int autoscrollBeltSize = 20;
  82 static const unsigned backgroundObscurationTestMaxDepth = 4;
  83
  84 static bool skipBodyBackground(const RenderBox* bodyElementRenderer)
  85 {
  86     ASSERT(bodyElementRenderer->isBody());
  87     // The <body> only paints its background if the root element has defined a background independent of the body,
  88     // or if the <body>'s parent is not the document element's renderer (e.g. inside SVG foreignObject).
  89     RenderObject* documentElementRenderer = bodyElementRenderer->document().documentElement()->renderer();
  90     return documentElementRenderer
  91         && !documentElementRenderer->hasBackground()
  92         && (documentElementRenderer == bodyElementRenderer->parent());
  93 }
  94
  95 RenderBox::RenderBox(ContainerNode* node)
  96     : RenderBoxModelObject(node)
  97     , m_intrinsicContentLogicalHeight(-1)
  98     , m_minPreferredLogicalWidth(-1)
  99     , m_maxPreferredLogicalWidth(-1)
 100 {
 101     setIsBox();
 102 }
 103
 104 void RenderBox::willBeDestroyed()
 105 {
 106     clearOverrideSize();
 107     clearContainingBlockOverrideSize();
 108
 109     RenderBlock::removePercentHeightDescendantIfNeeded(this);
 110
 111     ShapeOutsideInfo::removeInfo(*this);
 112
 113     RenderBoxModelObject::willBeDestroyed();
 114 }
 115
 116 void RenderBox::removeFloatingOrPositionedChildFromBlockLists()
 117 {
 118     ASSERT(isFloatingOrOutOfFlowPositioned());
 119
 120     if (documentBeingDestroyed())
 121         return;
 122
 123     if (isFloating()) {
 124         RenderBlockFlow* parentBlockFlow = 0;
 125         for (RenderObject* curr = parent(); curr && !curr->isRenderView(); curr = curr->parent()) {
 126             if (curr->isRenderBlockFlow()) {
 127                 RenderBlockFlow* currBlockFlow = toRenderBlockFlow(curr);
 128                 if (!parentBlockFlow || currBlockFlow->containsFloat(this))
 129                     parentBlockFlow = currBlockFlow;
 130             }
 131         }
 132
 133         if (parentBlockFlow) {
 134             parentBlockFlow->markSiblingsWithFloatsForLayout(this);
 135             parentBlockFlow->markAllDescendantsWithFloatsForLayout(this, false);
 136         }
 137     }
 138
 139     if (isOutOfFlowPositioned())
 140         RenderBlock::removePositionedObject(this);
 141 }
 142
 143 void RenderBox::styleWillChange(StyleDifference diff, const RenderStyle& newStyle)
 144 {
 145     RenderStyle* oldStyle = style();
 146     if (oldStyle) {
 147         // The background of the root element or the body element could propagate up to
 148         // the canvas.  Just dirty the entire canvas when our style changes substantially.
 149         if ((diff.needsRepaint() || diff.needsLayout()) && node()
 150             && (isHTMLHtmlElement(*node()) || isHTMLBodyElement(*node()))) {
 151             view()->paintInvalidationForWholeRenderer();
 152
 153             if (oldStyle->hasEntirelyFixedBackground() != newStyle.hasEntirelyFixedBackground())
 154                 view()->compositor()->setNeedsUpdateFixedBackground();
 155         }
 156
 157         // When a layout hint happens and an object's position style changes, we have to do a layout
 158         // to dirty the render tree using the old position value now.
 159         if (diff.needsFullLayout() && parent() && oldStyle->position() != newStyle.position()) {
 160             markContainingBlocksForLayout();
 161             if (oldStyle->position() == StaticPosition)
 162                 paintInvalidationForWholeRenderer();
 163             else if (newStyle.hasOutOfFlowPosition())
 164                 parent()->setChildNeedsLayout();
 165             if (isFloating() && !isOutOfFlowPositioned() && newStyle.hasOutOfFlowPosition())
 166                 removeFloatingOrPositionedChildFromBlockLists();
 167         }
 168     // FIXME: This branch runs when !oldStyle, which means that layout was never called
 169     // so what's the point in invalidating the whole view that we never painted?
 170     } else if (isBody()) {
 171         view()->paintInvalidationForWholeRenderer();
 172     }
 173
 174     RenderBoxModelObject::styleWillChange(diff, newStyle);
 175 }
 176
 177 void RenderBox::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
 178 {
 179     // Horizontal writing mode definition is updated in RenderBoxModelObject::updateFromStyle,
 180     // (as part of the RenderBoxModelObject::styleDidChange call below). So, we can safely cache the horizontal
 181     // writing mode value before style change here.
 182     bool oldHorizontalWritingMode = isHorizontalWritingMode();
 183
 184     RenderBoxModelObject::styleDidChange(diff, oldStyle);
 185
 186     RenderStyle* newStyle = style();
 187     if (needsLayout() && oldStyle) {
 188         RenderBlock::removePercentHeightDescendantIfNeeded(this);
 189
 190         // Normally we can do optimized positioning layout for absolute/fixed positioned objects. There is one special case, however, which is
 191         // when the positioned object's margin-before is changed. In this case the parent has to get a layout in order to run margin collapsing
 192         // to determine the new static position.
 193         if (isOutOfFlowPositioned() && newStyle->hasStaticBlockPosition(isHorizontalWritingMode()) && oldStyle->marginBefore() != newStyle->marginBefore()
 194             && parent() && !parent()->normalChildNeedsLayout())
 195             parent()->setChildNeedsLayout();
 196     }
 197
 198     if (RenderBlock::hasPercentHeightContainerMap() && slowFirstChild()
 199         && oldHorizontalWritingMode != isHorizontalWritingMode())
 200         RenderBlock::clearPercentHeightDescendantsFrom(this);
 201
 202     // If our zoom factor changes and we have a defined scrollLeft/Top, we need to adjust that value into the
 203     // new zoomed coordinate space.
 204     if (hasOverflowClip() && oldStyle && newStyle && oldStyle->effectiveZoom() != newStyle->effectiveZoom() && layer()) {
 205         if (int left = layer()->scrollableArea()->scrollXOffset()) {
 206             left = (left / oldStyle->effectiveZoom()) * newStyle->effectiveZoom();
 207             layer()->scrollableArea()->scrollToXOffset(left);
 208         }
 209         if (int top = layer()->scrollableArea()->scrollYOffset()) {
 210             top = (top / oldStyle->effectiveZoom()) * newStyle->effectiveZoom();
 211             layer()->scrollableArea()->scrollToYOffset(top);
 212         }
 213     }
 214
 215     // Our opaqueness might have changed without triggering layout.
 216     if (diff.needsRepaint()) {
 217         RenderObject* parentToInvalidate = parent();
 218         for (unsigned i = 0; i < backgroundObscurationTestMaxDepth && parentToInvalidate; ++i) {
 219             parentToInvalidate->invalidateBackgroundObscurationStatus();
 220             parentToInvalidate = parentToInvalidate->parent();
 221         }
 222     }
 223
 224     if (isDocumentElement() || isBody())
 225         document().view()->recalculateScrollbarOverlayStyle();
 226
 227     updateShapeOutsideInfoAfterStyleChange(*style(), oldStyle);
 228     updateGridPositionAfterStyleChange(oldStyle);
 229 }
 230
 231 void RenderBox::updateShapeOutsideInfoAfterStyleChange(const RenderStyle& style, const RenderStyle* oldStyle)
 232 {
 233     const ShapeValue* shapeOutside = style.shapeOutside();
 234     const ShapeValue* oldShapeOutside = oldStyle ? oldStyle->shapeOutside() : RenderStyle::initialShapeOutside();
 235
 236     Length shapeMargin = style.shapeMargin();
 237     Length oldShapeMargin = oldStyle ? oldStyle->shapeMargin() : RenderStyle::initialShapeMargin();
 238
 239     float shapeImageThreshold = style.shapeImageThreshold();
 240     float oldShapeImageThreshold = oldStyle ? oldStyle->shapeImageThreshold() : RenderStyle::initialShapeImageThreshold();
 241
 242     // FIXME: A future optimization would do a deep comparison for equality. (bug 100811)
 243     if (shapeOutside == oldShapeOutside && shapeMargin == oldShapeMargin && shapeImageThreshold == oldShapeImageThreshold)
 244         return;
 245
 246     if (!shapeOutside)
 247         ShapeOutsideInfo::removeInfo(*this);
 248     else
 249         ShapeOutsideInfo::ensureInfo(*this).markShapeAsDirty();
 250
 251     if (shapeOutside || shapeOutside != oldShapeOutside)
 252         markShapeOutsideDependentsForLayout();
 253 }
 254
 255 void RenderBox::updateGridPositionAfterStyleChange(const RenderStyle* oldStyle)
 256 {
 257     if (!oldStyle || !parent() || !parent()->isRenderGrid())
 258         return;
 259
 260     if (oldStyle->gridColumnStart() == style()->gridColumnStart()
 261         && oldStyle->gridColumnEnd() == style()->gridColumnEnd()
 262         && oldStyle->gridRowStart() == style()->gridRowStart()
 263         && oldStyle->gridRowEnd() == style()->gridRowEnd()
 264         && oldStyle->order() == style()->order()
 265         && oldStyle->hasOutOfFlowPosition() == style()->hasOutOfFlowPosition())
 266         return;
 267
 268     // It should be possible to not dirty the grid in some cases (like moving an explicitly placed grid item).
 269     // For now, it's more simple to just always recompute the grid.
 270     toRenderGrid(parent())->dirtyGrid();
 271 }
 272
 273 void RenderBox::updateFromStyle()
 274 {
 275     RenderBoxModelObject::updateFromStyle();
 276
 277     RenderStyle* styleToUse = style();
 278     bool isRootObject = isDocumentElement();
 279     bool isViewObject = isRenderView();
 280
 281     // The root and the RenderView always paint their backgrounds/borders.
 282     if (isRootObject || isViewObject)
 283         setHasBoxDecorations(true);
 284
 285     setFloating(!isOutOfFlowPositioned() && styleToUse->isFloating());
 286
 287     bool boxHasOverflowClip = false;
 288     if (!styleToUse->isOverflowVisible() && isRenderBlock() && !isViewObject) {
 289         // If overflow has been propagated to the viewport, it has no effect here.
 290         if (node() != document().viewportDefiningElement()) {
 291             boxHasOverflowClip = true;
 292             if (!hasOverflowClip()) {
 293                 // If we are getting an overflow clip, preemptively erase any overflowing content.
 294                 // FIXME: This should probably consult RenderOverflow.
 295                 if (!RuntimeEnabledFeatures::repaintAfterLayoutEnabled())
 296                     paintInvalidationForWholeRenderer();
 297             }
 298         }
 299     }
 300
 301     if (RuntimeEnabledFeatures::repaintAfterLayoutEnabled() && (boxHasOverflowClip != hasOverflowClip())) {
 302         // FIXME: This shouldn't be required if we tracked the visual overflow
 303         // generated by positioned children or self painting layers. crbug.com/345403
 304         for (RenderObject* child = slowFirstChild(); child; child = child->nextSibling())
 305             child->setShouldDoFullPaintInvalidationIfSelfPaintingLayer(true);
 306     }
 307
 308     setHasOverflowClip(boxHasOverflowClip);
 309
 310     setHasTransform(styleToUse->hasTransformRelatedProperty());
 311     setHasReflection(styleToUse->boxReflect());
 312 }
 313
 314 void RenderBox::layout()
 315 {
 316     ASSERT(needsLayout());
 317
 318     RenderObject* child = slowFirstChild();
 319     if (!child) {
 320         clearNeedsLayout();
 321         return;
 322     }
 323
 324     LayoutState state(*this, locationOffset());
 325     while (child) {
 326         child->layoutIfNeeded();
 327         ASSERT(!child->needsLayout());
 328         child = child->nextSibling();
 329     }
 330     invalidateBackgroundObscurationStatus();
 331     clearNeedsLayout();
 332 }
 333
 334 // More IE extensions.  clientWidth and clientHeight represent the interior of an object
 335 // excluding border and scrollbar.
 336 LayoutUnit RenderBox::clientWidth() const
 337 {
 338     return width() - borderLeft() - borderRight() - verticalScrollbarWidth();
 339 }
 340
 341 LayoutUnit RenderBox::clientHeight() const
 342 {
 343     return height() - borderTop() - borderBottom() - horizontalScrollbarHeight();
 344 }
 345
 346 int RenderBox::pixelSnappedClientWidth() const
 347 {
 348     return snapSizeToPixel(clientWidth(), x() + clientLeft());
 349 }
 350
 351 int RenderBox::pixelSnappedClientHeight() const
 352 {
 353     return snapSizeToPixel(clientHeight(), y() + clientTop());
 354 }
 355
 356 int RenderBox::pixelSnappedOffsetWidth() const
 357 {
 358     return snapSizeToPixel(offsetWidth(), x() + clientLeft());
 359 }
 360
 361 int RenderBox::pixelSnappedOffsetHeight() const
 362 {
 363     return snapSizeToPixel(offsetHeight(), y() + clientTop());
 364 }
 365
 366 LayoutUnit RenderBox::scrollWidth() const
 367 {
 368     if (hasOverflowClip())
 369         return layer()->scrollableArea()->scrollWidth();
 370     // For objects with visible overflow, this matches IE.
 371     // FIXME: Need to work right with writing modes.
 372     if (style()->isLeftToRightDirection())
 373         return max(clientWidth(), layoutOverflowRect().maxX() - borderLeft());
 374     return clientWidth() - min<LayoutUnit>(0, layoutOverflowRect().x() - borderLeft());
 375 }
 376
 377 LayoutUnit RenderBox::scrollHeight() const
 378 {
 379     if (hasOverflowClip())
 380         return layer()->scrollableArea()->scrollHeight();
 381     // For objects with visible overflow, this matches IE.
 382     // FIXME: Need to work right with writing modes.
 383     return max(clientHeight(), layoutOverflowRect().maxY() - borderTop());
 384 }
 385
 386 LayoutUnit RenderBox::scrollLeft() const
 387 {
 388     return hasOverflowClip() ? layer()->scrollableArea()->scrollXOffset() : 0;
 389 }
 390
 391 LayoutUnit RenderBox::scrollTop() const
 392 {
 393     return hasOverflowClip() ? layer()->scrollableArea()->scrollYOffset() : 0;
 394 }
 395
 396 int RenderBox::pixelSnappedScrollWidth() const
 397 {
 398     return snapSizeToPixel(scrollWidth(), x() + clientLeft());
 399 }
 400
 401 int RenderBox::pixelSnappedScrollHeight() const
 402 {
 403     if (hasOverflowClip())
 404         return layer()->scrollableArea()->scrollHeight();
 405     // For objects with visible overflow, this matches IE.
 406     // FIXME: Need to work right with writing modes.
 407     return snapSizeToPixel(scrollHeight(), y() + clientTop());
 408 }
 409
 410 void RenderBox::setScrollLeft(LayoutUnit newLeft)
 411 {
 412     // This doesn't hit in any tests, but since the equivalent code in setScrollTop
 413     // does, presumably this code does as well.
 414     DisableCompositingQueryAsserts disabler;
 415
 416     if (hasOverflowClip())
 417         layer()->scrollableArea()->scrollToXOffset(newLeft, ScrollOffsetClamped);
 418 }
 419
 420 void RenderBox::setScrollTop(LayoutUnit newTop)
 421 {
 422     // Hits in compositing/overflow/do-not-assert-on-invisible-composited-layers.html
 423     DisableCompositingQueryAsserts disabler;
 424
 425     if (hasOverflowClip())
 426         layer()->scrollableArea()->scrollToYOffset(newTop, ScrollOffsetClamped);
 427 }
 428
 429 void RenderBox::scrollToOffset(const IntSize& offset)
 430 {
 431     ASSERT(hasOverflowClip());
 432
 433     // This doesn't hit in any tests, but since the equivalent code in setScrollTop
 434     // does, presumably this code does as well.
 435     DisableCompositingQueryAsserts disabler;
 436     layer()->scrollableArea()->scrollToOffset(offset, ScrollOffsetClamped);
 437 }
 438
 439 static inline bool frameElementAndViewPermitScroll(HTMLFrameElementBase* frameElementBase, FrameView* frameView)
 440 {
 441     // If scrollbars aren't explicitly forbidden, permit scrolling.
 442     if (frameElementBase && frameElementBase->scrollingMode() != ScrollbarAlwaysOff)
 443         return true;
 444
 445     // If scrollbars are forbidden, user initiated scrolls should obviously be ignored.
 446     if (frameView->wasScrolledByUser())
 447         return false;
 448
 449     // Forbid autoscrolls when scrollbars are off, but permits other programmatic scrolls,
 450     // like navigation to an anchor.
 451     Page* page = frameView->frame().page();
 452     if (!page)
 453         return false;
 454     return !page->autoscrollController().autoscrollInProgress();
 455 }
 456
 457 void RenderBox::scrollRectToVisible(const LayoutRect& rect, const ScrollAlignment& alignX, const ScrollAlignment& alignY)
 458 {
 459     // Presumably the same issue as in setScrollTop. See crbug.com/343132.
 460     DisableCompositingQueryAsserts disabler;
 461
 462     RenderBox* parentBox = 0;
 463     LayoutRect newRect = rect;
 464
 465     bool restrictedByLineClamp = false;
 466     if (parent()) {
 467         parentBox = parent()->enclosingBox();
 468         restrictedByLineClamp = !parent()->style()->lineClamp().isNone();
 469     }
 470
 471     if (hasOverflowClip() && !restrictedByLineClamp) {
 472         // Don't scroll to reveal an overflow layer that is restricted by the -webkit-line-clamp property.
 473         // This will prevent us from revealing text hidden by the slider in Safari RSS.
 474         newRect = layer()->scrollableArea()->exposeRect(rect, alignX, alignY);
 475     } else if (!parentBox && canBeProgramaticallyScrolled()) {
 476         if (FrameView* frameView = this->frameView()) {
 477             Element* ownerElement = document().ownerElement();
 478
 479             if (ownerElement && ownerElement->renderer()) {
 480                 HTMLFrameElementBase* frameElementBase = 0;
 481
 482                 if (isHTMLFrameElement(*ownerElement) || isHTMLIFrameElement(*ownerElement))
 483                     frameElementBase = toHTMLFrameElementBase(ownerElement);
 484
 485                 if (frameElementAndViewPermitScroll(frameElementBase, frameView)) {
 486                     LayoutRect viewRect = frameView->visibleContentRect();
 487                     LayoutRect exposeRect = ScrollAlignment::getRectToExpose(viewRect, rect, alignX, alignY);
 488
 489                     int xOffset = roundToInt(exposeRect.x());
 490                     int yOffset = roundToInt(exposeRect.y());
 491                     // Adjust offsets if they're outside of the allowable range.
 492                     xOffset = max(0, min(frameView->contentsWidth(), xOffset));
 493                     yOffset = max(0, min(frameView->contentsHeight(), yOffset));
 494
 495                     frameView->setScrollPosition(IntPoint(xOffset, yOffset));
 496                     if (frameView->safeToPropagateScrollToParent()) {
 497                         parentBox = ownerElement->renderer()->enclosingBox();
 498                         // FIXME: This doesn't correctly convert the rect to
 499                         // absolute coordinates in the parent.
 500                         newRect.setX(rect.x() - frameView->scrollX() + frameView->x());
 501                         newRect.setY(rect.y() - frameView->scrollY() + frameView->y());
 502                     } else {
 503                         parentBox = 0;
 504                     }
 505                 }
 506             } else {
 507                 if (frame()->settings()->pinchVirtualViewportEnabled()) {
 508                     PinchViewport& pinchViewport = frame()->page()->frameHost().pinchViewport();
 509                     LayoutRect r = ScrollAlignment::getRectToExpose(LayoutRect(pinchViewport.visibleRectInDocument()), rect, alignX, alignY);
 510                     pinchViewport.scrollIntoView(r);
 511                 } else {
 512                     LayoutRect viewRect = frameView->visibleContentRect();
 513                     LayoutRect r = ScrollAlignment::getRectToExpose(viewRect, rect, alignX, alignY);
 514                     frameView->setScrollPosition(roundedIntPoint(r.location()));
 515                 }
 516             }
 517         }
 518     }
 519
 520     if (frame()->page()->autoscrollController().autoscrollInProgress())
 521         parentBox = enclosingScrollableBox();
 522
 523     if (parentBox)
 524         parentBox->scrollRectToVisible(newRect, alignX, alignY);
 525 }
 526
 527 void RenderBox::absoluteRects(Vector<IntRect>& rects, const LayoutPoint& accumulatedOffset) const
 528 {
 529     rects.append(pixelSnappedIntRect(accumulatedOffset, size()));
 530 }
 531
 532 void RenderBox::absoluteQuads(Vector<FloatQuad>& quads, bool* wasFixed) const
 533 {
 534     quads.append(localToAbsoluteQuad(FloatRect(0, 0, width().toFloat(), height().toFloat()), 0 /* mode */, wasFixed));
 535 }
 536
 537 void RenderBox::updateLayerTransformAfterLayout()
 538 {
 539     // Transform-origin depends on box size, so we need to update the layer transform after layout.
 540     if (hasLayer())
 541         layer()->updateTransformationMatrix();
 542 }
 543
 544 LayoutUnit RenderBox::constrainLogicalWidthByMinMax(LayoutUnit logicalWidth, LayoutUnit availableWidth, RenderBlock* cb) const
 545 {
 546     RenderStyle* styleToUse = style();
 547     if (!styleToUse->logicalMaxWidth().isUndefined())
 548         logicalWidth = min(logicalWidth, computeLogicalWidthUsing(MaxSize, styleToUse->logicalMaxWidth(), availableWidth, cb));
 549     return max(logicalWidth, computeLogicalWidthUsing(MinSize, styleToUse->logicalMinWidth(), availableWidth, cb));
 550 }
 551
 552 LayoutUnit RenderBox::constrainLogicalHeightByMinMax(LayoutUnit logicalHeight, LayoutUnit intrinsicContentHeight) const
 553 {
 554     RenderStyle* styleToUse = style();
 555     if (!styleToUse->logicalMaxHeight().isUndefined()) {
 556         LayoutUnit maxH = computeLogicalHeightUsing(styleToUse->logicalMaxHeight(), intrinsicContentHeight);
 557         if (maxH != -1)
 558             logicalHeight = min(logicalHeight, maxH);
 559     }
 560     return max(logicalHeight, computeLogicalHeightUsing(styleToUse->logicalMinHeight(), intrinsicContentHeight));
 561 }
 562
 563 LayoutUnit RenderBox::constrainContentBoxLogicalHeightByMinMax(LayoutUnit logicalHeight, LayoutUnit intrinsicContentHeight) const
 564 {
 565     RenderStyle* styleToUse = style();
 566     if (!styleToUse->logicalMaxHeight().isUndefined()) {
 567         LayoutUnit maxH = computeContentLogicalHeight(styleToUse->logicalMaxHeight(), intrinsicContentHeight);
 568         if (maxH != -1)
 569             logicalHeight = min(logicalHeight, maxH);
 570     }
 571     return max(logicalHeight, computeContentLogicalHeight(styleToUse->logicalMinHeight(), intrinsicContentHeight));
 572 }
 573
 574 IntRect RenderBox::absoluteContentBox() const
 575 {
 576     // This is wrong with transforms and flipped writing modes.
 577     IntRect rect = pixelSnappedIntRect(contentBoxRect());
 578     FloatPoint absPos = localToAbsolute();
 579     rect.move(absPos.x(), absPos.y());
 580     return rect;
 581 }
 582
 583 FloatQuad RenderBox::absoluteContentQuad() const
 584 {
 585     LayoutRect rect = contentBoxRect();
 586     return localToAbsoluteQuad(FloatRect(rect));
 587 }
 588
 589 void RenderBox::addFocusRingRects(Vector<IntRect>& rects, const LayoutPoint& additionalOffset, const RenderLayerModelObject*)
 590 {
 591     if (!size().isEmpty())
 592         rects.append(pixelSnappedIntRect(additionalOffset, size()));
 593 }
 594
 595 bool RenderBox::canResize() const
 596 {
 597     // We need a special case for <iframe> because they never have
 598     // hasOverflowClip(). However, they do "implicitly" clip their contents, so
 599     // we want to allow resizing them also.
 600     return (hasOverflowClip() || isRenderIFrame()) && style()->resize() != RESIZE_NONE;
 601 }
 602
 603 void RenderBox::addLayerHitTestRects(LayerHitTestRects& layerRects, const RenderLayer* currentLayer, const LayoutPoint& layerOffset, const LayoutRect& containerRect) const
 604 {
 605     LayoutPoint adjustedLayerOffset = layerOffset + locationOffset();
 606     RenderBoxModelObject::addLayerHitTestRects(layerRects, currentLayer, adjustedLayerOffset, containerRect);
 607 }
 608
 609 void RenderBox::computeSelfHitTestRects(Vector<LayoutRect>& rects, const LayoutPoint& layerOffset) const
 610 {
 611     if (!size().isEmpty())
 612         rects.append(LayoutRect(layerOffset, size()));
 613 }
 614
 615 int RenderBox::reflectionOffset() const
 616 {
 617     if (!style()->boxReflect())
 618         return 0;
 619     if (style()->boxReflect()->direction() == ReflectionLeft || style()->boxReflect()->direction() == ReflectionRight)
 620         return valueForLength(style()->boxReflect()->offset(), borderBoxRect().width());
 621     return valueForLength(style()->boxReflect()->offset(), borderBoxRect().height());
 622 }
 623
 624 LayoutRect RenderBox::reflectedRect(const LayoutRect& r) const
 625 {
 626     if (!style()->boxReflect())
 627         return LayoutRect();
 628
 629     LayoutRect box = borderBoxRect();
 630     LayoutRect result = r;
 631     switch (style()->boxReflect()->direction()) {
 632         case ReflectionBelow:
 633             result.setY(box.maxY() + reflectionOffset() + (box.maxY() - r.maxY()));
 634             break;
 635         case ReflectionAbove:
 636             result.setY(box.y() - reflectionOffset() - box.height() + (box.maxY() - r.maxY()));
 637             break;
 638         case ReflectionLeft:
 639             result.setX(box.x() - reflectionOffset() - box.width() + (box.maxX() - r.maxX()));
 640             break;
 641         case ReflectionRight:
 642             result.setX(box.maxX() + reflectionOffset() + (box.maxX() - r.maxX()));
 643             break;
 644     }
 645     return result;
 646 }
 647
 648 int RenderBox::verticalScrollbarWidth() const
 649 {
 650     if (!hasOverflowClip() || style()->overflowY() == OOVERLAY)
 651         return 0;
 652
 653     return layer()->scrollableArea()->verticalScrollbarWidth();
 654 }
 655
 656 int RenderBox::horizontalScrollbarHeight() const
 657 {
 658     if (!hasOverflowClip() || style()->overflowX() == OOVERLAY)
 659         return 0;
 660
 661     return layer()->scrollableArea()->horizontalScrollbarHeight();
 662 }
 663
 664 int RenderBox::instrinsicScrollbarLogicalWidth() const
 665 {
 666     if (!hasOverflowClip())
 667         return 0;
 668
 669     if (isHorizontalWritingMode() && style()->overflowY() == OSCROLL) {
 670         ASSERT(layer()->scrollableArea() && layer()->scrollableArea()->hasVerticalScrollbar());
 671         return verticalScrollbarWidth();
 672     }
 673
 674     if (!isHorizontalWritingMode() && style()->overflowX() == OSCROLL) {
 675         ASSERT(layer()->scrollableArea() && layer()->scrollableArea()->hasHorizontalScrollbar());
 676         return horizontalScrollbarHeight();
 677     }
 678
 679     return 0;
 680 }
 681
 682 bool RenderBox::scroll(ScrollDirection direction, ScrollGranularity granularity, float delta)
 683 {
 684     // Presumably the same issue as in setScrollTop. See crbug.com/343132.
 685     DisableCompositingQueryAsserts disabler;
 686
 687     // Logical scroll is a higher level concept, all directions by here must be physical
 688     ASSERT(!isLogical(direction));
 689
 690     if (!layer() || !layer()->scrollableArea())
 691         return false;
 692
 693     return layer()->scrollableArea()->scroll(direction, granularity, delta);
 694 }
 695
 696 bool RenderBox::canBeScrolledAndHasScrollableArea() const
 697 {
 698     return canBeProgramaticallyScrolled() && (pixelSnappedScrollHeight() != pixelSnappedClientHeight() || pixelSnappedScrollWidth() != pixelSnappedClientWidth());
 699 }
 700
 701 bool RenderBox::canBeProgramaticallyScrolled() const
 702 {
 703     Node* node = this->node();
 704     if (node && node->isDocumentNode())
 705         return true;
 706
 707     if (!hasOverflowClip())
 708         return false;
 709
 710     bool hasScrollableOverflow = hasScrollableOverflowX() || hasScrollableOverflowY();
 711     if (scrollsOverflow() && hasScrollableOverflow)
 712         return true;
 713
 714     return node && node->rendererIsEditable();
 715 }
 716
 717 bool RenderBox::usesCompositedScrolling() const
 718 {
 719     return hasOverflowClip() && hasLayer() && layer()->scrollableArea()->usesCompositedScrolling();
 720 }
 721
 722 void RenderBox::autoscroll(const IntPoint& position)
 723 {
 724     LocalFrame* frame = this->frame();
 725     if (!frame)
 726         return;
 727
 728     FrameView* frameView = frame->view();
 729     if (!frameView)
 730         return;
 731
 732     IntPoint currentDocumentPosition = frameView->windowToContents(position);
 733     scrollRectToVisible(LayoutRect(currentDocumentPosition, LayoutSize(1, 1)), ScrollAlignment::alignToEdgeIfNeeded, ScrollAlignment::alignToEdgeIfNeeded);
 734 }
 735
 736 bool RenderBox::autoscrollInProgress() const
 737 {
 738     return frame() && frame()->page() && frame()->page()->autoscrollController().autoscrollInProgress(this);
 739 }
 740
 741 // There are two kinds of renderer that can autoscroll.
 742 bool RenderBox::canAutoscroll() const
 743 {
 744     if (node() && node()->isDocumentNode())
 745         return view()->frameView()->isScrollable();
 746
 747     // Check for a box that can be scrolled in its own right.
 748     return canBeScrolledAndHasScrollableArea();
 749 }
 750
 751 // If specified point is in border belt, returned offset denotes direction of
 752 // scrolling.
 753 IntSize RenderBox::calculateAutoscrollDirection(const IntPoint& windowPoint) const
 754 {
 755     if (!frame())
 756         return IntSize();
 757
 758     FrameView* frameView = frame()->view();
 759     if (!frameView)
 760         return IntSize();
 761
 762     IntRect box(absoluteBoundingBoxRect());
 763     box.move(view()->frameView()->scrollOffset());
 764     IntRect windowBox = view()->frameView()->contentsToWindow(box);
 765
 766     IntPoint windowAutoscrollPoint = windowPoint;
 767
 768     if (windowAutoscrollPoint.x() < windowBox.x() + autoscrollBeltSize)
 769         windowAutoscrollPoint.move(-autoscrollBeltSize, 0);
 770     else if (windowAutoscrollPoint.x() > windowBox.maxX() - autoscrollBeltSize)
 771         windowAutoscrollPoint.move(autoscrollBeltSize, 0);
 772
 773     if (windowAutoscrollPoint.y() < windowBox.y() + autoscrollBeltSize)
 774         windowAutoscrollPoint.move(0, -autoscrollBeltSize);
 775     else if (windowAutoscrollPoint.y() > windowBox.maxY() - autoscrollBeltSize)
 776         windowAutoscrollPoint.move(0, autoscrollBeltSize);
 777
 778     return windowAutoscrollPoint - windowPoint;
 779 }
 780
 781 RenderBox* RenderBox::findAutoscrollable(RenderObject* renderer)
 782 {
 783     while (renderer && !(renderer->isBox() && toRenderBox(renderer)->canAutoscroll())) {
 784         if (!renderer->parent() && renderer->node() == renderer->document() && renderer->document().ownerElement())
 785             renderer = renderer->document().ownerElement()->renderer();
 786         else
 787             renderer = renderer->parent();
 788     }
 789
 790     return renderer && renderer->isBox() ? toRenderBox(renderer) : 0;
 791 }
 792
 793 static inline int adjustedScrollDelta(int beginningDelta)
 794 {
 795     // This implemention matches Firefox's.
 796     // http://mxr.mozilla.org/firefox/source/toolkit/content/widgets/browser.xml#856.
 797     const int speedReducer = 12;
 798
 799     int adjustedDelta = beginningDelta / speedReducer;
 800     if (adjustedDelta > 1)
 801         adjustedDelta = static_cast<int>(adjustedDelta * sqrt(static_cast<double>(adjustedDelta))) - 1;
 802     else if (adjustedDelta < -1)
 803         adjustedDelta = static_cast<int>(adjustedDelta * sqrt(static_cast<double>(-adjustedDelta))) + 1;
 804
 805     return adjustedDelta;
 806 }
 807
 808 static inline IntSize adjustedScrollDelta(const IntSize& delta)
 809 {
 810     return IntSize(adjustedScrollDelta(delta.width()), adjustedScrollDelta(delta.height()));
 811 }
 812
 813 void RenderBox::panScroll(const IntPoint& sourcePoint)
 814 {
 815     LocalFrame* frame = this->frame();
 816     if (!frame)
 817         return;
 818
 819     IntPoint lastKnownMousePosition = frame->eventHandler().lastKnownMousePosition();
 820
 821     // We need to check if the last known mouse position is out of the window. When the mouse is out of the window, the position is incoherent
 822     static IntPoint previousMousePosition;
 823     if (lastKnownMousePosition.x() < 0 || lastKnownMousePosition.y() < 0)
 824         lastKnownMousePosition = previousMousePosition;
 825     else
 826         previousMousePosition = lastKnownMousePosition;
 827
 828     IntSize delta = lastKnownMousePosition - sourcePoint;
 829
 830     if (abs(delta.width()) <= ScrollView::noPanScrollRadius) // at the center we let the space for the icon
 831         delta.setWidth(0);
 832     if (abs(delta.height()) <= ScrollView::noPanScrollRadius)
 833         delta.setHeight(0);
 834
 835     scrollByRecursively(adjustedScrollDelta(delta), ScrollOffsetClamped);
 836 }
 837
 838 void RenderBox::scrollByRecursively(const IntSize& delta, ScrollOffsetClamping clamp)
 839 {
 840     if (delta.isZero())
 841         return;
 842
 843     bool restrictedByLineClamp = false;
 844     if (parent())
 845         restrictedByLineClamp = !parent()->style()->lineClamp().isNone();
 846
 847     if (hasOverflowClip() && !restrictedByLineClamp) {
 848         IntSize newScrollOffset = layer()->scrollableArea()->adjustedScrollOffset() + delta;
 849         layer()->scrollableArea()->scrollToOffset(newScrollOffset, clamp);
 850
 851         // If this layer can't do the scroll we ask the next layer up that can scroll to try
 852         IntSize remainingScrollOffset = newScrollOffset - layer()->scrollableArea()->adjustedScrollOffset();
 853         if (!remainingScrollOffset.isZero() && parent()) {
 854             if (RenderBox* scrollableBox = enclosingScrollableBox())
 855                 scrollableBox->scrollByRecursively(remainingScrollOffset, clamp);
 856
 857             LocalFrame* frame = this->frame();
 858             if (frame && frame->page())
 859                 frame->page()->autoscrollController().updateAutoscrollRenderer();
 860         }
 861     } else if (view()->frameView()) {
 862         // If we are here, we were called on a renderer that can be programmatically scrolled, but doesn't
 863         // have an overflow clip. Which means that it is a document node that can be scrolled.
 864         view()->frameView()->scrollBy(delta);
 865
 866         // FIXME: If we didn't scroll the whole way, do we want to try looking at the frames ownerElement?
 867         // https://bugs.webkit.org/show_bug.cgi?id=28237
 868     }
 869 }
 870
 871 bool RenderBox::needsPreferredWidthsRecalculation() const
 872 {
 873     return style()->paddingStart().isPercent() || style()->paddingEnd().isPercent();
 874 }
 875
 876 IntSize RenderBox::scrolledContentOffset() const
 877 {
 878     ASSERT(hasOverflowClip());
 879     ASSERT(hasLayer());
 880     return layer()->scrollableArea()->scrollOffset();
 881 }
 882
 883 LayoutSize RenderBox::cachedSizeForOverflowClip() const
 884 {
 885     ASSERT(hasOverflowClip());
 886     ASSERT(hasLayer());
 887     return layer()->size();
 888 }
 889
 890 void RenderBox::applyCachedClipAndScrollOffsetForRepaint(LayoutRect& paintRect) const
 891 {
 892     flipForWritingMode(paintRect);
 893     paintRect.move(-scrolledContentOffset()); // For overflow:auto/scroll/hidden.
 894
 895     // Do not clip scroll layer contents to reduce the number of repaints while scrolling.
 896     if (usesCompositedScrolling()) {
 897         flipForWritingMode(paintRect);
 898         return;
 899     }
 900
 901     // height() is inaccurate if we're in the middle of a layout of this RenderBox, so use the
 902     // layer's size instead. Even if the layer's size is wrong, the layer itself will repaint
 903     // anyway if its size does change.
 904     LayoutRect clipRect(LayoutPoint(), cachedSizeForOverflowClip());
 905     paintRect = intersection(paintRect, clipRect);
 906     flipForWritingMode(paintRect);
 907 }
 908
 909 void RenderBox::computeIntrinsicLogicalWidths(LayoutUnit& minLogicalWidth, LayoutUnit& maxLogicalWidth) const
 910 {
 911     minLogicalWidth = minPreferredLogicalWidth() - borderAndPaddingLogicalWidth();
 912     maxLogicalWidth = maxPreferredLogicalWidth() - borderAndPaddingLogicalWidth();
 913 }
 914
 915 LayoutUnit RenderBox::minPreferredLogicalWidth() const
 916 {
 917     if (preferredLogicalWidthsDirty()) {
 918 #ifndef NDEBUG
 919         SetLayoutNeededForbiddenScope layoutForbiddenScope(const_cast<RenderBox&>(*this));
 920 #endif
 921         const_cast<RenderBox*>(this)->computePreferredLogicalWidths();
 922     }
 923
 924     return m_minPreferredLogicalWidth;
 925 }
 926
 927 LayoutUnit RenderBox::maxPreferredLogicalWidth() const
 928 {
 929     if (preferredLogicalWidthsDirty()) {
 930 #ifndef NDEBUG
 931         SetLayoutNeededForbiddenScope layoutForbiddenScope(const_cast<RenderBox&>(*this));
 932 #endif
 933         const_cast<RenderBox*>(this)->computePreferredLogicalWidths();
 934     }
 935
 936     return m_maxPreferredLogicalWidth;
 937 }
 938
 939 bool RenderBox::hasOverrideHeight() const
 940 {
 941     return m_rareData && m_rareData->m_overrideLogicalContentHeight != -1;
 942 }
 943
 944 bool RenderBox::hasOverrideWidth() const
 945 {
 946     return m_rareData && m_rareData->m_overrideLogicalContentWidth != -1;
 947 }
 948
 949 void RenderBox::setOverrideLogicalContentHeight(LayoutUnit height)
 950 {
 951     ASSERT(height >= 0);
 952     ensureRareData().m_overrideLogicalContentHeight = height;
 953 }
 954
 955 void RenderBox::setOverrideLogicalContentWidth(LayoutUnit width)
 956 {
 957     ASSERT(width >= 0);
 958     ensureRareData().m_overrideLogicalContentWidth = width;
 959 }
 960
 961 void RenderBox::clearOverrideLogicalContentHeight()
 962 {
 963     if (m_rareData)
 964         m_rareData->m_overrideLogicalContentHeight = -1;
 965 }
 966
 967 void RenderBox::clearOverrideLogicalContentWidth()
 968 {
 969     if (m_rareData)
 970         m_rareData->m_overrideLogicalContentWidth = -1;
 971 }
 972
 973 void RenderBox::clearOverrideSize()
 974 {
 975     clearOverrideLogicalContentHeight();
 976     clearOverrideLogicalContentWidth();
 977 }
 978
 979 LayoutUnit RenderBox::overrideLogicalContentWidth() const
 980 {
 981     ASSERT(hasOverrideWidth());
 982     return m_rareData->m_overrideLogicalContentWidth;
 983 }
 984
 985 LayoutUnit RenderBox::overrideLogicalContentHeight() const
 986 {
 987     ASSERT(hasOverrideHeight());
 988     return m_rareData->m_overrideLogicalContentHeight;
 989 }
 990
 991 LayoutUnit RenderBox::overrideContainingBlockContentLogicalWidth() const
 992 {
 993     ASSERT(hasOverrideContainingBlockLogicalWidth());
 994     return gOverrideContainingBlockLogicalWidthMap->get(this);
 995 }
 996
 997 LayoutUnit RenderBox::overrideContainingBlockContentLogicalHeight() const
 998 {
 999     ASSERT(hasOverrideContainingBlockLogicalHeight());
1000     return gOverrideContainingBlockLogicalHeightMap->get(this);
1001 }
1002
1003 bool RenderBox::hasOverrideContainingBlockLogicalWidth() const
1004 {
1005     return gOverrideContainingBlockLogicalWidthMap && gOverrideContainingBlockLogicalWidthMap->contains(this);
1006 }
1007
1008 bool RenderBox::hasOverrideContainingBlockLogicalHeight() const
1009 {
1010     return gOverrideContainingBlockLogicalHeightMap && gOverrideContainingBlockLogicalHeightMap->contains(this);
1011 }
1012
1013 void RenderBox::setOverrideContainingBlockContentLogicalWidth(LayoutUnit logicalWidth)
1014 {
1015     if (!gOverrideContainingBlockLogicalWidthMap)
1016         gOverrideContainingBlockLogicalWidthMap = new OverrideSizeMap;
1017     gOverrideContainingBlockLogicalWidthMap->set(this, logicalWidth);
1018 }
1019
1020 void RenderBox::setOverrideContainingBlockContentLogicalHeight(LayoutUnit logicalHeight)
1021 {
1022     if (!gOverrideContainingBlockLogicalHeightMap)
1023         gOverrideContainingBlockLogicalHeightMap = new OverrideSizeMap;
1024     gOverrideContainingBlockLogicalHeightMap->set(this, logicalHeight);
1025 }
1026
1027 void RenderBox::clearContainingBlockOverrideSize()
1028 {
1029     if (gOverrideContainingBlockLogicalWidthMap)
1030         gOverrideContainingBlockLogicalWidthMap->remove(this);
1031     clearOverrideContainingBlockContentLogicalHeight();
1032 }
1033
1034 void RenderBox::clearOverrideContainingBlockContentLogicalHeight()
1035 {
1036     if (gOverrideContainingBlockLogicalHeightMap)
1037         gOverrideContainingBlockLogicalHeightMap->remove(this);
1038 }
1039
1040 LayoutUnit RenderBox::adjustBorderBoxLogicalWidthForBoxSizing(LayoutUnit width) const
1041 {
1042     LayoutUnit bordersPlusPadding = borderAndPaddingLogicalWidth();
1043     if (style()->boxSizing() == CONTENT_BOX)
1044         return width + bordersPlusPadding;
1045     return max(width, bordersPlusPadding);
1046 }
1047
1048 LayoutUnit RenderBox::adjustBorderBoxLogicalHeightForBoxSizing(LayoutUnit height) const
1049 {
1050     LayoutUnit bordersPlusPadding = borderAndPaddingLogicalHeight();
1051     if (style()->boxSizing() == CONTENT_BOX)
1052         return height + bordersPlusPadding;
1053     return max(height, bordersPlusPadding);
1054 }
1055
1056 LayoutUnit RenderBox::adjustContentBoxLogicalWidthForBoxSizing(LayoutUnit width) const
1057 {
1058     if (style()->boxSizing() == BORDER_BOX)
1059         width -= borderAndPaddingLogicalWidth();
1060     return max<LayoutUnit>(0, width);
1061 }
1062
1063 LayoutUnit RenderBox::adjustContentBoxLogicalHeightForBoxSizing(LayoutUnit height) const
1064 {
1065     if (style()->boxSizing() == BORDER_BOX)
1066         height -= borderAndPaddingLogicalHeight();
1067     return max<LayoutUnit>(0, height);
1068 }
1069
1070 // Hit Testing
1071 bool RenderBox::nodeAtPoint(const HitTestRequest& request, HitTestResult& result, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, HitTestAction action)
1072 {
1073     LayoutPoint adjustedLocation = accumulatedOffset + location();
1074
1075     // Check kids first.
1076     for (RenderObject* child = slowLastChild(); child; child = child->previousSibling()) {
1077         if ((!child->hasLayer() || !toRenderLayerModelObject(child)->layer()->isSelfPaintingLayer()) && child->nodeAtPoint(request, result, locationInContainer, adjustedLocation, action)) {
1078             updateHitTestResult(result, locationInContainer.point() - toLayoutSize(adjustedLocation));
1079             return true;
1080         }
1081     }
1082
1083     // Check our bounds next. For this purpose always assume that we can only be hit in the
1084     // foreground phase (which is true for replaced elements like images).
1085     LayoutRect boundsRect = borderBoxRect();
1086     boundsRect.moveBy(adjustedLocation);
1087     if (visibleToHitTestRequest(request) && action == HitTestForeground && locationInContainer.intersects(boundsRect)) {
1088         updateHitTestResult(result, locationInContainer.point() - toLayoutSize(adjustedLocation));
1089         if (!result.addNodeToRectBasedTestResult(node(), request, locationInContainer, boundsRect))
1090             return true;
1091     }
1092
1093     return false;
1094 }
1095
1096 // --------------------- painting stuff -------------------------------
1097
1098 void RenderBox::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
1099 {
1100     LayoutPoint adjustedPaintOffset = paintOffset + location();
1101     // default implementation. Just pass paint through to the children
1102     PaintInfo childInfo(paintInfo);
1103     childInfo.updatePaintingRootForChildren(this);
1104     for (RenderObject* child = slowFirstChild(); child; child = child->nextSibling())
1105         child->paint(childInfo, adjustedPaintOffset);
1106 }
1107
1108 void RenderBox::paintRootBoxFillLayers(const PaintInfo& paintInfo)
1109 {
1110     if (paintInfo.skipRootBackground())
1111         return;
1112
1113     RenderObject* rootBackgroundRenderer = rendererForRootBackground();
1114
1115     const FillLayer* bgLayer = rootBackgroundRenderer->style()->backgroundLayers();
1116     Color bgColor = rootBackgroundRenderer->resolveColor(CSSPropertyBackgroundColor);
1117
1118     paintFillLayers(paintInfo, bgColor, bgLayer, view()->backgroundRect(this), BackgroundBleedNone, CompositeSourceOver, rootBackgroundRenderer);
1119 }
1120
1121 BackgroundBleedAvoidance RenderBox::determineBackgroundBleedAvoidance(GraphicsContext* context) const
1122 {
1123     if (context->paintingDisabled())
1124         return BackgroundBleedNone;
1125
1126     const RenderStyle* style = this->style();
1127
1128     if (!style->hasBackground() || !style->hasBorder() || !style->hasBorderRadius() || canRenderBorderImage())
1129         return BackgroundBleedNone;
1130
1131     // FIXME: See crbug.com/382491. getCTM does not accurately reflect the scale at the time content is
1132     // rasterized, and should not be relied on to make decisions about bleeding.
1133     AffineTransform ctm = context->getCTM();
1134     FloatSize contextScaling(static_cast<float>(ctm.xScale()), static_cast<float>(ctm.yScale()));
1135
1136     // Because RoundedRect uses IntRect internally the inset applied by the
1137     // BackgroundBleedShrinkBackground strategy cannot be less than one integer
1138     // layout coordinate, even with subpixel layout enabled. To take that into
1139     // account, we clamp the contextScaling to 1.0 for the following test so
1140     // that borderObscuresBackgroundEdge can only return true if the border
1141     // widths are greater than 2 in both layout coordinates and screen
1142     // coordinates.
1143     // This precaution will become obsolete if RoundedRect is ever promoted to
1144     // a sub-pixel representation.
1145     if (contextScaling.width() > 1)
1146         contextScaling.setWidth(1);
1147     if (contextScaling.height() > 1)
1148         contextScaling.setHeight(1);
1149
1150     if (borderObscuresBackgroundEdge(contextScaling))
1151         return BackgroundBleedShrinkBackground;
1152     if (!style->hasAppearance() && borderObscuresBackground() && backgroundHasOpaqueTopLayer())
1153         return BackgroundBleedBackgroundOverBorder;
1154
1155     return BackgroundBleedClipBackground;
1156 }
1157
1158 void RenderBox::paintBoxDecorations(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
1159 {
1160     if (!paintInfo.shouldPaintWithinRoot(this))
1161         return;
1162
1163     LayoutRect paintRect = borderBoxRect();
1164     paintRect.moveBy(paintOffset);
1165     paintBoxDecorationsWithRect(paintInfo, paintOffset, paintRect);
1166 }
1167
1168 void RenderBox::paintBoxDecorationsWithRect(PaintInfo& paintInfo, const LayoutPoint& paintOffset, const LayoutRect& paintRect)
1169 {
1170     BackgroundBleedAvoidance bleedAvoidance = determineBackgroundBleedAvoidance(paintInfo.context);
1171
1172     // FIXME: Should eventually give the theme control over whether the box shadow should paint, since controls could have
1173     // custom shadows of their own.
1174     if (!boxShadowShouldBeAppliedToBackground(bleedAvoidance))
1175         paintBoxShadow(paintInfo, paintRect, style(), Normal);
1176
1177     GraphicsContextStateSaver stateSaver(*paintInfo.context, false);
1178     if (bleedAvoidance == BackgroundBleedClipBackground) {
1179         stateSaver.save();
1180         RoundedRect border = style()->getRoundedBorderFor(paintRect);
1181         paintInfo.context->clipRoundedRect(border);
1182     }
1183
1184     paintBackgroundWithBorderAndBoxShadow(paintInfo, paintRect, bleedAvoidance);
1185 }
1186
1187 void RenderBox::paintBackgroundWithBorderAndBoxShadow(PaintInfo& paintInfo, const LayoutRect& paintRect, BackgroundBleedAvoidance bleedAvoidance)
1188 {
1189     // If we have a native theme appearance, paint that before painting our background.
1190     // The theme will tell us whether or not we should also paint the CSS background.
1191     IntRect snappedPaintRect(pixelSnappedIntRect(paintRect));
1192     bool themePainted = style()->hasAppearance() && !RenderTheme::theme().paint(this, paintInfo, snappedPaintRect);
1193     if (!themePainted) {
1194         if (bleedAvoidance == BackgroundBleedBackgroundOverBorder)
1195             paintBorder(paintInfo, paintRect, style(), bleedAvoidance);
1196
1197         paintBackground(paintInfo, paintRect, bleedAvoidance);
1198
1199         if (style()->hasAppearance())
1200             RenderTheme::theme().paintDecorations(this, paintInfo, snappedPaintRect);
1201     }
1202     paintBoxShadow(paintInfo, paintRect, style(), Inset);
1203
1204     // The theme will tell us whether or not we should also paint the CSS border.
1205     if (bleedAvoidance != BackgroundBleedBackgroundOverBorder && (!style()->hasAppearance() || (!themePainted && RenderTheme::theme().paintBorderOnly(this, paintInfo, snappedPaintRect))) && style()->hasBorder() && !(isTable() && toRenderTable(this)->collapseBorders()))
1206         paintBorder(paintInfo, paintRect, style(), bleedAvoidance);
1207 }
1208
1209 void RenderBox::paintBackground(const PaintInfo& paintInfo, const LayoutRect& paintRect, BackgroundBleedAvoidance bleedAvoidance)
1210 {
1211     if (isDocumentElement()) {
1212         paintRootBoxFillLayers(paintInfo);
1213         return;
1214     }
1215     if (isBody() && skipBodyBackground(this))
1216         return;
1217     if (backgroundIsKnownToBeObscured())
1218         return;
1219     paintFillLayers(paintInfo, resolveColor(CSSPropertyBackgroundColor), style()->backgroundLayers(), paintRect, bleedAvoidance);
1220 }
1221
1222 bool RenderBox::getBackgroundPaintedExtent(LayoutRect& paintedExtent) const
1223 {
1224     ASSERT(hasBackground());
1225     LayoutRect backgroundRect = pixelSnappedIntRect(borderBoxRect());
1226
1227     Color backgroundColor = resolveColor(CSSPropertyBackgroundColor);
1228     if (backgroundColor.alpha()) {
1229         paintedExtent = backgroundRect;
1230         return true;
1231     }
1232
1233     if (!style()->backgroundLayers()->image() || style()->backgroundLayers()->next()) {
1234         paintedExtent =  backgroundRect;
1235         return true;
1236     }
1237
1238     BackgroundImageGeometry geometry;
1239     calculateBackgroundImageGeometry(0, style()->backgroundLayers(), backgroundRect, geometry);
1240     if (geometry.hasNonLocalGeometry())
1241         return false;
1242     paintedExtent = geometry.destRect();
1243     return true;
1244 }
1245
1246 bool RenderBox::backgroundIsKnownToBeOpaqueInRect(const LayoutRect& localRect) const
1247 {
1248     if (isBody() && skipBodyBackground(this))
1249         return false;
1250
1251     Color backgroundColor = resolveColor(CSSPropertyBackgroundColor);
1252     if (backgroundColor.hasAlpha())
1253         return false;
1254
1255     // If the element has appearance, it might be painted by theme.
1256     // We cannot be sure if theme paints the background opaque.
1257     // In this case it is safe to not assume opaqueness.
1258     // FIXME: May be ask theme if it paints opaque.
1259     if (style()->hasAppearance())
1260         return false;
1261     // FIXME: Check the opaqueness of background images.
1262
1263     // FIXME: Use rounded rect if border radius is present.
1264     if (style()->hasBorderRadius())
1265         return false;
1266     // FIXME: The background color clip is defined by the last layer.
1267     if (style()->backgroundLayers()->next())
1268         return false;
1269     LayoutRect backgroundRect;
1270     switch (style()->backgroundClip()) {
1271     case BorderFillBox:
1272         backgroundRect = borderBoxRect();
1273         break;
1274     case PaddingFillBox:
1275         backgroundRect = paddingBoxRect();
1276         break;
1277     case ContentFillBox:
1278         backgroundRect = contentBoxRect();
1279         break;
1280     default:
1281         break;
1282     }
1283     return backgroundRect.contains(localRect);
1284 }
1285
1286 static bool isCandidateForOpaquenessTest(RenderBox* childBox)
1287 {
1288     RenderStyle* childStyle = childBox->style();
1289     if (childStyle->position() != StaticPosition && childBox->containingBlock() != childBox->parent())
1290         return false;
1291     if (childStyle->visibility() != VISIBLE || childStyle->shapeOutside())
1292         return false;
1293     if (!childBox->width() || !childBox->height())
1294         return false;
1295     if (RenderLayer* childLayer = childBox->layer()) {
1296         // FIXME: perhaps this could be less conservative?
1297         if (childLayer->compositingState() != NotComposited)
1298             return false;
1299         // FIXME: Deal with z-index.
1300         if (!childStyle->hasAutoZIndex())
1301             return false;
1302         if (childLayer->hasTransform() || childLayer->isTransparent() || childLayer->hasFilter())
1303             return false;
1304         if (childBox->hasOverflowClip() && childStyle->hasBorderRadius())
1305             return false;
1306     }
1307     return true;
1308 }
1309
1310 bool RenderBox::foregroundIsKnownToBeOpaqueInRect(const LayoutRect& localRect, unsigned maxDepthToTest) const
1311 {
1312     if (!maxDepthToTest)
1313         return false;
1314     for (RenderObject* child = slowFirstChild(); child; child = child->nextSibling()) {
1315         if (!child->isBox())
1316             continue;
1317         RenderBox* childBox = toRenderBox(child);
1318         if (!isCandidateForOpaquenessTest(childBox))
1319             continue;
1320         LayoutPoint childLocation = childBox->location();
1321         if (childBox->isRelPositioned())
1322             childLocation.move(childBox->relativePositionOffset());
1323         LayoutRect childLocalRect = localRect;
1324         childLocalRect.moveBy(-childLocation);
1325         if (childLocalRect.y() < 0 || childLocalRect.x() < 0) {
1326             // If there is unobscured area above/left of a static positioned box then the rect is probably not covered.
1327             if (childBox->style()->position() == StaticPosition)
1328                 return false;
1329             continue;
1330         }
1331         if (childLocalRect.maxY() > childBox->height() || childLocalRect.maxX() > childBox->width())
1332             continue;
1333         if (childBox->backgroundIsKnownToBeOpaqueInRect(childLocalRect))
1334             return true;
1335         if (childBox->foregroundIsKnownToBeOpaqueInRect(childLocalRect, maxDepthToTest - 1))
1336             return true;
1337     }
1338     return false;
1339 }
1340
1341 bool RenderBox::computeBackgroundIsKnownToBeObscured()
1342 {
1343     // Test to see if the children trivially obscure the background.
1344     // FIXME: This test can be much more comprehensive.
1345     if (!hasBackground())
1346         return false;
1347     // Table and root background painting is special.
1348     if (isTable() || isDocumentElement())
1349         return false;
1350     // FIXME: box-shadow is painted while background painting.
1351     if (style()->boxShadow())
1352         return false;
1353     LayoutRect backgroundRect;
1354     if (!getBackgroundPaintedExtent(backgroundRect))
1355         return false;
1356     return foregroundIsKnownToBeOpaqueInRect(backgroundRect, backgroundObscurationTestMaxDepth);
1357 }
1358
1359 bool RenderBox::backgroundHasOpaqueTopLayer() const
1360 {
1361     const FillLayer* fillLayer = style()->backgroundLayers();
1362     if (!fillLayer || fillLayer->clip() != BorderFillBox)
1363         return false;
1364
1365     // Clipped with local scrolling
1366     if (hasOverflowClip() && fillLayer->attachment() == LocalBackgroundAttachment)
1367         return false;
1368
1369     if (fillLayer->hasOpaqueImage(this) && fillLayer->hasRepeatXY() && fillLayer->image()->canRender(*this, style()->effectiveZoom()))
1370         return true;
1371
1372     // If there is only one layer and no image, check whether the background color is opaque
1373     if (!fillLayer->next() && !fillLayer->hasImage()) {
1374         Color bgColor = resolveColor(CSSPropertyBackgroundColor);
1375         if (bgColor.alpha() == 255)
1376             return true;
1377     }
1378
1379     return false;
1380 }
1381
1382 void RenderBox::paintMask(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
1383 {
1384     if (!paintInfo.shouldPaintWithinRoot(this) || style()->visibility() != VISIBLE || paintInfo.phase != PaintPhaseMask || paintInfo.context->paintingDisabled())
1385         return;
1386
1387     LayoutRect paintRect = LayoutRect(paintOffset, size());
1388     paintMaskImages(paintInfo, paintRect);
1389 }
1390
1391 void RenderBox::paintClippingMask(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
1392 {
1393     if (!paintInfo.shouldPaintWithinRoot(this) || style()->visibility() != VISIBLE || paintInfo.phase != PaintPhaseClippingMask || paintInfo.context->paintingDisabled())
1394         return;
1395
1396     if (!layer() || layer()->compositingState() != PaintsIntoOwnBacking)
1397         return;
1398
1399     // We should never have this state in this function. A layer with a mask
1400     // should have always created its own backing if it became composited.
1401     ASSERT(layer()->compositingState() != HasOwnBackingButPaintsIntoAncestor);
1402
1403     LayoutRect paintRect = LayoutRect(paintOffset, size());
1404     paintInfo.context->fillRect(pixelSnappedIntRect(paintRect), Color::black);
1405 }
1406
1407 void RenderBox::paintMaskImages(const PaintInfo& paintInfo, const LayoutRect& paintRect)
1408 {
1409     // Figure out if we need to push a transparency layer to render our mask.
1410     bool pushTransparencyLayer = false;
1411     bool compositedMask = hasLayer() && layer()->hasCompositedMask();
1412     bool flattenCompositingLayers = view()->frameView() && view()->frameView()->paintBehavior() & PaintBehaviorFlattenCompositingLayers;
1413     CompositeOperator compositeOp = CompositeSourceOver;
1414
1415     bool allMaskImagesLoaded = true;
1416
1417     if (!compositedMask || flattenCompositingLayers) {
1418         pushTransparencyLayer = true;
1419         StyleImage* maskBoxImage = style()->maskBoxImage().image();
1420         const FillLayer* maskLayers = style()->maskLayers();
1421
1422         // Don't render a masked element until all the mask images have loaded, to prevent a flash of unmasked content.
1423         if (maskBoxImage)
1424             allMaskImagesLoaded &= maskBoxImage->isLoaded();
1425
1426         if (maskLayers)
1427             allMaskImagesLoaded &= maskLayers->imagesAreLoaded();
1428
1429         paintInfo.context->setCompositeOperation(CompositeDestinationIn);
1430         paintInfo.context->beginTransparencyLayer(1);
1431         compositeOp = CompositeSourceOver;
1432     }
1433
1434     if (allMaskImagesLoaded) {
1435         paintFillLayers(paintInfo, Color::transparent, style()->maskLayers(), paintRect, BackgroundBleedNone, compositeOp);
1436         paintNinePieceImage(paintInfo.context, paintRect, style(), style()->maskBoxImage(), compositeOp);
1437     }
1438
1439     if (pushTransparencyLayer)
1440         paintInfo.context->endLayer();
1441 }
1442
1443 void RenderBox::paintFillLayers(const PaintInfo& paintInfo, const Color& c, const FillLayer* fillLayer, const LayoutRect& rect,
1444     BackgroundBleedAvoidance bleedAvoidance, CompositeOperator op, RenderObject* backgroundObject)
1445 {
1446     Vector<const FillLayer*, 8> layers;
1447     const FillLayer* curLayer = fillLayer;
1448     bool shouldDrawBackgroundInSeparateBuffer = false;
1449     while (curLayer) {
1450         layers.append(curLayer);
1451         // Stop traversal when an opaque layer is encountered.
1452         // FIXME : It would be possible for the following occlusion culling test to be more aggressive
1453         // on layers with no repeat by testing whether the image covers the layout rect.
1454         // Testing that here would imply duplicating a lot of calculations that are currently done in
1455         // RenderBoxModelObject::paintFillLayerExtended. A more efficient solution might be to move
1456         // the layer recursion into paintFillLayerExtended, or to compute the layer geometry here
1457         // and pass it down.
1458
1459         if (!shouldDrawBackgroundInSeparateBuffer && curLayer->blendMode() != blink::WebBlendModeNormal)
1460             shouldDrawBackgroundInSeparateBuffer = true;
1461
1462         // The clipOccludesNextLayers condition must be evaluated first to avoid short-circuiting.
1463         if (curLayer->clipOccludesNextLayers(curLayer == fillLayer) && curLayer->hasOpaqueImage(this) && curLayer->image()->canRender(*this, style()->effectiveZoom()) && curLayer->hasRepeatXY() && curLayer->blendMode() == blink::WebBlendModeNormal && !boxShadowShouldBeAppliedToBackground(bleedAvoidance))
1464             break;
1465         curLayer = curLayer->next();
1466     }
1467
1468     GraphicsContext* context = paintInfo.context;
1469     if (!context)
1470         shouldDrawBackgroundInSeparateBuffer = false;
1471     if (shouldDrawBackgroundInSeparateBuffer)
1472         context->beginTransparencyLayer(1);
1473
1474     Vector<const FillLayer*>::const_reverse_iterator topLayer = layers.rend();
1475     for (Vector<const FillLayer*>::const_reverse_iterator it = layers.rbegin(); it != topLayer; ++it)
1476         paintFillLayer(paintInfo, c, *it, rect, bleedAvoidance, op, backgroundObject);
1477
1478     if (shouldDrawBackgroundInSeparateBuffer)
1479         context->endLayer();
1480 }
1481
1482 void RenderBox::paintFillLayer(const PaintInfo& paintInfo, const Color& c, const FillLayer* fillLayer, const LayoutRect& rect,
1483     BackgroundBleedAvoidance bleedAvoidance, CompositeOperator op, RenderObject* backgroundObject)
1484 {
1485     paintFillLayerExtended(paintInfo, c, fillLayer, rect, bleedAvoidance, 0, LayoutSize(), op, backgroundObject);
1486 }
1487
1488 void RenderBox::imageChanged(WrappedImagePtr image, const IntRect*)
1489 {
1490     if (!parent())
1491         return;
1492
1493     AllowPaintInvalidationScope scoper(frameView());
1494
1495     if ((style()->borderImage().image() && style()->borderImage().image()->data() == image) ||
1496         (style()->maskBoxImage().image() && style()->maskBoxImage().image()->data() == image)) {
1497         paintInvalidationForWholeRenderer();
1498         return;
1499     }
1500
1501     ShapeValue* shapeOutsideValue = style()->shapeOutside();
1502     if (!frameView()->isInPerformLayout() && isFloating() && shapeOutsideValue && shapeOutsideValue->image() && shapeOutsideValue->image()->data() == image) {
1503         ShapeOutsideInfo::ensureInfo(*this).markShapeAsDirty();
1504         markShapeOutsideDependentsForLayout();
1505     }
1506
1507     bool didFullRepaint = repaintLayerRectsForImage(image, style()->backgroundLayers(), true);
1508     if (!didFullRepaint)
1509         repaintLayerRectsForImage(image, style()->maskLayers(), false);
1510 }
1511
1512 bool RenderBox::repaintLayerRectsForImage(WrappedImagePtr image, const FillLayer* layers, bool drawingBackground)
1513 {
1514     LayoutRect rendererRect;
1515     RenderBox* layerRenderer = 0;
1516
1517     for (const FillLayer* curLayer = layers; curLayer; curLayer = curLayer->next()) {
1518         if (curLayer->image() && image == curLayer->image()->data() && curLayer->image()->canRender(*this, style()->effectiveZoom())) {
1519             // Now that we know this image is being used, compute the renderer and the rect if we haven't already.
1520             if (!layerRenderer) {
1521                 bool drawingRootBackground = drawingBackground && (isDocumentElement() || (isBody() && !document().documentElement()->renderer()->hasBackground()));
1522                 if (drawingRootBackground) {
1523                     layerRenderer = view();
1524
1525                     LayoutUnit rw;
1526                     LayoutUnit rh;
1527
1528                     if (FrameView* frameView = toRenderView(layerRenderer)->frameView()) {
1529                         rw = frameView->contentsWidth();
1530                         rh = frameView->contentsHeight();
1531                     } else {
1532                         rw = layerRenderer->width();
1533                         rh = layerRenderer->height();
1534                     }
1535                     rendererRect = LayoutRect(-layerRenderer->marginLeft(),
1536                         -layerRenderer->marginTop(),
1537                         max(layerRenderer->width() + layerRenderer->marginWidth() + layerRenderer->borderLeft() + layerRenderer->borderRight(), rw),
1538                         max(layerRenderer->height() + layerRenderer->marginHeight() + layerRenderer->borderTop() + layerRenderer->borderBottom(), rh));
1539                 } else {
1540                     layerRenderer = this;
1541                     rendererRect = borderBoxRect();
1542                 }
1543             }
1544
1545             BackgroundImageGeometry geometry;
1546             layerRenderer->calculateBackgroundImageGeometry(0, curLayer, rendererRect, geometry);
1547             if (geometry.hasNonLocalGeometry()) {
1548                 // Rather than incur the costs of computing the paintContainer for renderers with fixed backgrounds
1549                 // in order to get the right destRect, just repaint the entire renderer.
1550                 layerRenderer->paintInvalidationForWholeRenderer();
1551                 return true;
1552             }
1553
1554             layerRenderer->invalidatePaintRectangle(geometry.destRect());
1555             if (geometry.destRect() == rendererRect)
1556                 return true;
1557         }
1558     }
1559     return false;
1560 }
1561
1562 void RenderBox::invalidateTreeAfterLayout(const RenderLayerModelObject& paintInvalidationContainer)
1563 {
1564     // FIXME: Currently only using this logic for RenderBox and its ilk. Ideally, RenderBlockFlows with
1565     // inline children should track a dirty rect in local coordinates for dirty lines instead of invalidating
1566     // the world.
1567     // FIXME: We should still be recursing through inline's children, as they can have boxes, but we don't
1568     // appear to have tests for this?
1569     // FIXME: SVG should probably also go through this unified paint invalidation system.
1570
1571     ASSERT(RuntimeEnabledFeatures::repaintAfterLayoutEnabled());
1572     ASSERT(!needsLayout());
1573
1574     if (!shouldCheckForPaintInvalidationAfterLayout())
1575         return;
1576
1577     bool establishesNewPaintInvalidationContainer = isPaintInvalidationContainer();
1578     const RenderLayerModelObject& newPaintInvalidationContainer = *adjustCompositedContainerForSpecialAncestors(establishesNewPaintInvalidationContainer ? this : &paintInvalidationContainer);
1579     // FIXME: This assert should be re-enabled when we move paint invalidation to after compositing update. crbug.com/360286
1580     // ASSERT(&newPaintInvalidationContainer == containerForPaintInvalidation());
1581
1582     const LayoutRect oldPaintInvalidationRect = previousPaintInvalidationRect();
1583     const LayoutPoint oldPositionFromPaintInvalidationContainer = previousPositionFromPaintInvalidationContainer();
1584     setPreviousPaintInvalidationRect(boundsRectForPaintInvalidation(&newPaintInvalidationContainer));
1585     setPreviousPositionFromPaintInvalidationContainer(RenderLayer::positionFromPaintInvalidationContainer(this, &newPaintInvalidationContainer));
1586
1587     // If we are set to do a full paint invalidation that means the RenderView will be
1588     // issue paint invalidations. We can then skip issuing of paint invalidations for the child
1589     // renderers as they'll be covered by the RenderView.
1590     if (view()->doingFullRepaint()) {
1591         LayoutState state(*this, isTableRow() ? LayoutSize() : locationOffset());
1592         RenderObject::invalidateTreeAfterLayout(newPaintInvalidationContainer);
1593         return;
1594     }
1595
1596     if ((onlyNeededPositionedMovementLayout() && compositingState() != PaintsIntoOwnBacking)
1597         || (shouldDoFullPaintInvalidationIfSelfPaintingLayer()
1598             && hasLayer()
1599             && layer()->isSelfPaintingLayer())) {
1600         setShouldDoFullPaintInvalidationAfterLayout(true);
1601     }
1602
1603     const LayoutRect& newPaintInvalidationRect = previousPaintInvalidationRect();
1604     const LayoutPoint& newPositionFromPaintInvalidationContainer = previousPositionFromPaintInvalidationContainer();
1605     bool didFullPaintInvalidation = invalidatePaintAfterLayoutIfNeeded(&newPaintInvalidationContainer,
1606         shouldDoFullPaintInvalidationAfterLayout(), oldPaintInvalidationRect, oldPositionFromPaintInvalidationContainer,
1607         &newPaintInvalidationRect, &newPositionFromPaintInvalidationContainer);
1608
1609     if (!didFullPaintInvalidation)
1610         invalidatePaintForOverflowIfNeeded();
1611
1612     // Issue paint invalidations for any scrollbars if there is a scrollable area for this renderer.
1613     if (enclosingLayer()) {
1614         if (RenderLayerScrollableArea* area = enclosingLayer()->scrollableArea()) {
1615             if (area->hasVerticalBarDamage())
1616                 invalidatePaintRectangle(area->verticalBarDamage());
1617             if (area->hasHorizontalBarDamage())
1618                 invalidatePaintRectangle(area->horizontalBarDamage());
1619             area->resetScrollbarDamage();
1620         }
1621     }
1622
1623     // FIXME: LayoutState should be enabled for other paint invalidation containers than the RenderView. crbug.com/363834
1624     if (establishesNewPaintInvalidationContainer && !isRenderView()) {
1625         ForceHorriblySlowRectMapping slowRectMapping(*this);
1626         RenderObject::invalidateTreeAfterLayout(newPaintInvalidationContainer);
1627     } else {
1628         // FIXME: This concept of a tree walking state for fast lookups should be generalized away from
1629         // just layout.
1630         // FIXME: Table rows shouldn't be special-cased.
1631         LayoutState state(*this, isTableRow() ? LayoutSize() : locationOffset());
1632         RenderObject::invalidateTreeAfterLayout(newPaintInvalidationContainer);
1633     }
1634 }
1635
1636 bool RenderBox::pushContentsClip(PaintInfo& paintInfo, const LayoutPoint& accumulatedOffset, ContentsClipBehavior contentsClipBehavior)
1637 {
1638     if (paintInfo.phase == PaintPhaseBlockBackground || paintInfo.phase == PaintPhaseSelfOutline || paintInfo.phase == PaintPhaseMask)
1639         return false;
1640
1641     bool isControlClip = hasControlClip();
1642     bool isOverflowClip = hasOverflowClip() && !layer()->isSelfPaintingLayer();
1643
1644     if (!isControlClip && !isOverflowClip)
1645         return false;
1646
1647     LayoutRect clipRect = isControlClip ? controlClipRect(accumulatedOffset) : overflowClipRect(accumulatedOffset);
1648     RoundedRect clipRoundedRect(0, 0, 0, 0);
1649     bool hasBorderRadius = style()->hasBorderRadius();
1650     if (hasBorderRadius)
1651         clipRoundedRect = style()->getRoundedInnerBorderFor(LayoutRect(accumulatedOffset, size()));
1652
1653     if (contentsClipBehavior == SkipContentsClipIfPossible) {
1654         LayoutRect contentsVisualOverflow = contentsVisualOverflowRect();
1655         if (contentsVisualOverflow.isEmpty())
1656             return false;
1657
1658         LayoutRect conservativeClipRect = clipRect;
1659         if (hasBorderRadius)
1660             conservativeClipRect.intersect(clipRoundedRect.radiusCenterRect());
1661         conservativeClipRect.moveBy(-accumulatedOffset);
1662         if (hasLayer())
1663             conservativeClipRect.move(scrolledContentOffset());
1664         if (conservativeClipRect.contains(contentsVisualOverflow))
1665             return false;
1666     }
1667
1668     if (paintInfo.phase == PaintPhaseOutline)
1669         paintInfo.phase = PaintPhaseChildOutlines;
1670     else if (paintInfo.phase == PaintPhaseChildBlockBackground) {
1671         paintInfo.phase = PaintPhaseBlockBackground;
1672         paintObject(paintInfo, accumulatedOffset);
1673         paintInfo.phase = PaintPhaseChildBlockBackgrounds;
1674     }
1675     paintInfo.context->save();
1676     if (hasBorderRadius)
1677         paintInfo.context->clipRoundedRect(clipRoundedRect);
1678     paintInfo.context->clip(pixelSnappedIntRect(clipRect));
1679     return true;
1680 }
1681
1682 void RenderBox::popContentsClip(PaintInfo& paintInfo, PaintPhase originalPhase, const LayoutPoint& accumulatedOffset)
1683 {
1684     ASSERT(hasControlClip() || (hasOverflowClip() && !layer()->isSelfPaintingLayer()));
1685
1686     paintInfo.context->restore();
1687     if (originalPhase == PaintPhaseOutline) {
1688         paintInfo.phase = PaintPhaseSelfOutline;
1689         paintObject(paintInfo, accumulatedOffset);
1690         paintInfo.phase = originalPhase;
1691     } else if (originalPhase == PaintPhaseChildBlockBackground)
1692         paintInfo.phase = originalPhase;
1693 }
1694
1695 LayoutRect RenderBox::overflowClipRect(const LayoutPoint& location, OverlayScrollbarSizeRelevancy relevancy)
1696 {
1697     // FIXME: When overflow-clip (CSS3) is implemented, we'll obtain the property
1698     // here.
1699     LayoutRect clipRect = borderBoxRect();
1700     clipRect.setLocation(location + clipRect.location() + LayoutSize(borderLeft(), borderTop()));
1701     clipRect.setSize(clipRect.size() - LayoutSize(borderLeft() + borderRight(), borderTop() + borderBottom()));
1702
1703     if (!hasOverflowClip())
1704         return clipRect;
1705
1706     // Subtract out scrollbars if we have them.
1707     if (style()->shouldPlaceBlockDirectionScrollbarOnLogicalLeft())
1708         clipRect.move(layer()->scrollableArea()->verticalScrollbarWidth(relevancy), 0);
1709     clipRect.contract(layer()->scrollableArea()->verticalScrollbarWidth(relevancy), layer()->scrollableArea()->horizontalScrollbarHeight(relevancy));
1710
1711     return clipRect;
1712 }
1713
1714 LayoutRect RenderBox::clipRect(const LayoutPoint& location)
1715 {
1716     LayoutRect borderBoxRect = this->borderBoxRect();
1717     LayoutRect clipRect = LayoutRect(borderBoxRect.location() + location, borderBoxRect.size());
1718
1719     if (!style()->clipLeft().isAuto()) {
1720         LayoutUnit c = valueForLength(style()->clipLeft(), borderBoxRect.width());
1721         clipRect.move(c, 0);
1722         clipRect.contract(c, 0);
1723     }
1724
1725     if (!style()->clipRight().isAuto())
1726         clipRect.contract(width() - valueForLength(style()->clipRight(), width()), 0);
1727
1728     if (!style()->clipTop().isAuto()) {
1729         LayoutUnit c = valueForLength(style()->clipTop(), borderBoxRect.height());
1730         clipRect.move(0, c);
1731         clipRect.contract(0, c);
1732     }
1733
1734     if (!style()->clipBottom().isAuto())
1735         clipRect.contract(0, height() - valueForLength(style()->clipBottom(), height()));
1736
1737     return clipRect;
1738 }
1739
1740 static LayoutUnit portionOfMarginNotConsumedByFloat(LayoutUnit childMargin, LayoutUnit contentSide, LayoutUnit offset)
1741 {
1742     if (childMargin <= 0)
1743         return 0;
1744     LayoutUnit contentSideWithMargin = contentSide + childMargin;
1745     if (offset > contentSideWithMargin)
1746         return childMargin;
1747     return offset - contentSide;
1748 }
1749
1750 LayoutUnit RenderBox::shrinkLogicalWidthToAvoidFloats(LayoutUnit childMarginStart, LayoutUnit childMarginEnd, const RenderBlockFlow* cb) const
1751 {
1752     LayoutUnit logicalTopPosition = logicalTop();
1753     LayoutUnit width = cb->availableLogicalWidthForLine(logicalTopPosition, false) - max<LayoutUnit>(0, childMarginStart) - max<LayoutUnit>(0, childMarginEnd);
1754
1755     // We need to see if margins on either the start side or the end side can contain the floats in question. If they can,
1756     // then just using the line width is inaccurate. In the case where a float completely fits, we don't need to use the line
1757     // offset at all, but can instead push all the way to the content edge of the containing block. In the case where the float
1758     // doesn't fit, we can use the line offset, but we need to grow it by the margin to reflect the fact that the margin was
1759     // "consumed" by the float. Negative margins aren't consumed by the float, and so we ignore them.
1760     width += portionOfMarginNotConsumedByFloat(childMarginStart, cb->startOffsetForContent(), cb->startOffsetForLine(logicalTopPosition, false));
1761     width += portionOfMarginNotConsumedByFloat(childMarginEnd, cb->endOffsetForContent(), cb->endOffsetForLine(logicalTopPosition, false));
1762     return width;
1763 }
1764
1765 LayoutUnit RenderBox::containingBlockLogicalWidthForContent() const
1766 {
1767     if (hasOverrideContainingBlockLogicalWidth())
1768         return overrideContainingBlockContentLogicalWidth();
1769
1770     RenderBlock* cb = containingBlock();
1771     return cb->availableLogicalWidth();
1772 }
1773
1774 LayoutUnit RenderBox::containingBlockLogicalHeightForContent(AvailableLogicalHeightType heightType) const
1775 {
1776     if (hasOverrideContainingBlockLogicalHeight())
1777         return overrideContainingBlockContentLogicalHeight();
1778
1779     RenderBlock* cb = containingBlock();
1780     return cb->availableLogicalHeight(heightType);
1781 }
1782
1783 LayoutUnit RenderBox::containingBlockAvailableLineWidth() const
1784 {
1785     RenderBlock* cb = containingBlock();
1786     if (cb->isRenderBlockFlow())
1787         return toRenderBlockFlow(cb)->availableLogicalWidthForLine(logicalTop(), false, availableLogicalHeight(IncludeMarginBorderPadding));
1788     return 0;
1789 }
1790
1791 LayoutUnit RenderBox::perpendicularContainingBlockLogicalHeight() const
1792 {
1793     if (hasOverrideContainingBlockLogicalHeight())
1794         return overrideContainingBlockContentLogicalHeight();
1795
1796     RenderBlock* cb = containingBlock();
1797     if (cb->hasOverrideHeight())
1798         return cb->overrideLogicalContentHeight();
1799
1800     RenderStyle* containingBlockStyle = cb->style();
1801     Length logicalHeightLength = containingBlockStyle->logicalHeight();
1802
1803     // FIXME: For now just support fixed heights.  Eventually should support percentage heights as well.
1804     if (!logicalHeightLength.isFixed()) {
1805         LayoutUnit fillFallbackExtent = containingBlockStyle->isHorizontalWritingMode() ? view()->frameView()->visibleHeight() : view()->frameView()->visibleWidth();
1806         LayoutUnit fillAvailableExtent = containingBlock()->availableLogicalHeight(ExcludeMarginBorderPadding);
1807         return min(fillAvailableExtent, fillFallbackExtent);
1808     }
1809
1810     // Use the content box logical height as specified by the style.
1811     return cb->adjustContentBoxLogicalHeightForBoxSizing(logicalHeightLength.value());
1812 }
1813
1814 void RenderBox::mapLocalToContainer(const RenderLayerModelObject* repaintContainer, TransformState& transformState, MapCoordinatesFlags mode, bool* wasFixed) const
1815 {
1816     if (repaintContainer == this)
1817         return;
1818
1819     if (RenderView* v = view()) {
1820         if (v->canMapUsingLayoutStateForContainer(repaintContainer)) {
1821             LayoutState* layoutState = v->layoutState();
1822             LayoutSize offset = layoutState->paintOffset() + locationOffset();
1823             if (style()->hasInFlowPosition() && layer())
1824                 offset += layer()->offsetForInFlowPosition();
1825             transformState.move(offset);
1826             return;
1827         }
1828     }
1829
1830     bool containerSkipped;
1831     RenderObject* o = container(repaintContainer, &containerSkipped);
1832     if (!o)
1833         return;
1834
1835     bool isFixedPos = style()->position() == FixedPosition;
1836     bool hasTransform = hasLayer() && layer()->transform();
1837     // If this box has a transform, it acts as a fixed position container for fixed descendants,
1838     // and may itself also be fixed position. So propagate 'fixed' up only if this box is fixed position.
1839     if (hasTransform && !isFixedPos)
1840         mode &= ~IsFixed;
1841     else if (isFixedPos)
1842         mode |= IsFixed;
1843
1844     if (wasFixed)
1845         *wasFixed = mode & IsFixed;
1846
1847     LayoutSize containerOffset = offsetFromContainer(o, roundedLayoutPoint(transformState.mappedPoint()));
1848
1849     bool preserve3D = mode & UseTransforms && (o->style()->preserves3D() || style()->preserves3D());
1850     if (mode & UseTransforms && shouldUseTransformFromContainer(o)) {
1851         TransformationMatrix t;
1852         getTransformFromContainer(o, containerOffset, t);
1853         transformState.applyTransform(t, preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform);
1854     } else
1855         transformState.move(containerOffset.width(), containerOffset.height(), preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform);
1856
1857     if (containerSkipped) {
1858         // There can't be a transform between repaintContainer and o, because transforms create containers, so it should be safe
1859         // to just subtract the delta between the repaintContainer and o.
1860         LayoutSize containerOffset = repaintContainer->offsetFromAncestorContainer(o);
1861         transformState.move(-containerOffset.width(), -containerOffset.height(), preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform);
1862         return;
1863     }
1864
1865     mode &= ~ApplyContainerFlip;
1866
1867     o->mapLocalToContainer(repaintContainer, transformState, mode, wasFixed);
1868 }
1869
1870 void RenderBox::mapAbsoluteToLocalPoint(MapCoordinatesFlags mode, TransformState& transformState) const
1871 {
1872     // We don't expect to be called during layout.
1873     ASSERT(!view() || !view()->layoutStateCachedOffsetsEnabled());
1874
1875     bool isFixedPos = style()->position() == FixedPosition;
1876     bool hasTransform = hasLayer() && layer()->transform();
1877     if (hasTransform && !isFixedPos) {
1878         // If this box has a transform, it acts as a fixed position container for fixed descendants,
1879         // and may itself also be fixed position. So propagate 'fixed' up only if this box is fixed position.
1880         mode &= ~IsFixed;
1881     } else if (isFixedPos)
1882         mode |= IsFixed;
1883
1884     RenderBoxModelObject::mapAbsoluteToLocalPoint(mode, transformState);
1885 }
1886
1887 LayoutSize RenderBox::offsetFromContainer(const RenderObject* o, const LayoutPoint& point, bool* offsetDependsOnPoint) const
1888 {
1889     ASSERT(o == container());
1890
1891     LayoutSize offset;
1892     if (isInFlowPositioned())
1893         offset += offsetForInFlowPosition();
1894
1895     if (!isInline() || isReplaced()) {
1896         if (!style()->hasOutOfFlowPosition() && o->hasColumns()) {
1897             const RenderBlock* block = toRenderBlock(o);
1898             LayoutRect columnRect(frameRect());
1899             block->adjustStartEdgeForWritingModeIncludingColumns(columnRect);
1900             offset += toSize(columnRect.location());
1901             LayoutPoint columnPoint = block->flipForWritingModeIncludingColumns(point + offset);
1902             offset = toLayoutSize(block->flipForWritingModeIncludingColumns(toLayoutPoint(offset)));
1903             offset += o->columnOffset(columnPoint);
1904             offset = block->flipForWritingMode(offset);
1905
1906             if (offsetDependsOnPoint)
1907                 *offsetDependsOnPoint = true;
1908         } else {
1909             offset += topLeftLocationOffset();
1910             if (o->isRenderFlowThread()) {
1911                 // So far the point has been in flow thread coordinates (i.e. as if everything in
1912                 // the fragmentation context lived in one tall single column). Convert it to a
1913                 // visual point now.
1914                 LayoutPoint pointInContainer = point + offset;
1915                 offset += o->columnOffset(pointInContainer);
1916                 if (offsetDependsOnPoint)
1917                     *offsetDependsOnPoint = true;
1918             }
1919         }
1920     }
1921
1922     if (o->hasOverflowClip())
1923         offset -= toRenderBox(o)->scrolledContentOffset();
1924
1925     if (style()->position() == AbsolutePosition && o->isInFlowPositioned() && o->isRenderInline())
1926         offset += toRenderInline(o)->offsetForInFlowPositionedInline(*this);
1927
1928     return offset;
1929 }
1930
1931 InlineBox* RenderBox::createInlineBox()
1932 {
1933     return new InlineBox(*this);
1934 }
1935
1936 void RenderBox::dirtyLineBoxes(bool fullLayout)
1937 {
1938     if (inlineBoxWrapper()) {
1939         if (fullLayout) {
1940             inlineBoxWrapper()->destroy();
1941             ASSERT(m_rareData);
1942             m_rareData->m_inlineBoxWrapper = 0;
1943         } else {
1944             inlineBoxWrapper()->dirtyLineBoxes();
1945         }
1946     }
1947 }
1948
1949 void RenderBox::positionLineBox(InlineBox* box)
1950 {
1951     if (isOutOfFlowPositioned()) {
1952         // Cache the x position only if we were an INLINE type originally.
1953         bool wasInline = style()->isOriginalDisplayInlineType();
1954         if (wasInline) {
1955             // The value is cached in the xPos of the box.  We only need this value if
1956             // our object was inline originally, since otherwise it would have ended up underneath
1957             // the inlines.
1958             RootInlineBox& root = box->root();
1959             root.block().setStaticInlinePositionForChild(this, root.lineTopWithLeading(), LayoutUnit::fromFloatRound(box->logicalLeft()));
1960             if (style()->hasStaticInlinePosition(box->isHorizontal()))
1961                 setChildNeedsLayout(MarkOnlyThis); // Just go ahead and mark the positioned object as needing layout, so it will update its position properly.
1962         } else {
1963             // Our object was a block originally, so we make our normal flow position be
1964             // just below the line box (as though all the inlines that came before us got
1965             // wrapped in an anonymous block, which is what would have happened had we been
1966             // in flow).  This value was cached in the y() of the box.
1967             layer()->setStaticBlockPosition(box->logicalTop());
1968             if (style()->hasStaticBlockPosition(box->isHorizontal()))
1969                 setChildNeedsLayout(MarkOnlyThis); // Just go ahead and mark the positioned object as needing layout, so it will update its position properly.
1970         }
1971
1972         // Nuke the box.
1973         box->remove(DontMarkLineBoxes);
1974         box->destroy();
1975     } else if (isReplaced()) {
1976         setLocation(roundedLayoutPoint(box->topLeft()));
1977         setInlineBoxWrapper(box);
1978     }
1979 }
1980
1981 void RenderBox::deleteLineBoxWrapper()
1982 {
1983     if (inlineBoxWrapper()) {
1984         if (!documentBeingDestroyed())
1985             inlineBoxWrapper()->remove();
1986         inlineBoxWrapper()->destroy();
1987         ASSERT(m_rareData);
1988         m_rareData->m_inlineBoxWrapper = 0;
1989     }
1990 }
1991
1992 LayoutRect RenderBox::clippedOverflowRectForPaintInvalidation(const RenderLayerModelObject* paintInvalidationContainer) const
1993 {
1994     if (style()->visibility() != VISIBLE && enclosingLayer()->subtreeIsInvisible())
1995         return LayoutRect();
1996
1997     LayoutRect r = visualOverflowRect();
1998
1999     RenderView* v = view();
2000     if (!RuntimeEnabledFeatures::repaintAfterLayoutEnabled() && v) {
2001         // FIXME: layoutDelta needs to be applied in parts before/after transforms and
2002         // repaint containers. https://bugs.webkit.org/show_bug.cgi?id=23308
2003         r.move(v->layoutDelta());
2004     }
2005
2006     mapRectToPaintInvalidationBacking(paintInvalidationContainer, r);
2007     return r;
2008 }
2009
2010 void RenderBox::mapRectToPaintInvalidationBacking(const RenderLayerModelObject* paintInvalidationContainer, LayoutRect& rect, bool fixed) const
2011 {
2012     // The rect we compute at each step is shifted by our x/y offset in the parent container's coordinate space.
2013     // Only when we cross a writing mode boundary will we have to possibly flipForWritingMode (to convert into a more appropriate
2014     // offset corner for the enclosing container).  This allows for a fully RL or BT document to repaint
2015     // properly even during layout, since the rect remains flipped all the way until the end.
2016     //
2017     // RenderView::computeRectForRepaint then converts the rect to physical coordinates.  We also convert to
2018     // physical when we hit a paintInvalidationContainer boundary. Therefore the final rect returned is always in the
2019     // physical coordinate space of the paintInvalidationContainer.
2020     RenderStyle* styleToUse = style();
2021     if (RenderView* v = view()) {
2022         // LayoutState is only valid for root-relative, non-fixed position repainting
2023         if (v->canMapUsingLayoutStateForContainer(paintInvalidationContainer) && styleToUse->position() != FixedPosition) {
2024             LayoutState* layoutState = v->layoutState();
2025
2026             if (layer() && layer()->transform())
2027                 rect = layer()->transform()->mapRect(pixelSnappedIntRect(rect));
2028
2029             // We can't trust the bits on RenderObject, because this might be called while re-resolving style.
2030             if (styleToUse->hasInFlowPosition() && layer())
2031                 rect.move(layer()->offsetForInFlowPosition());
2032
2033             rect.moveBy(location());
2034             rect.move(layoutState->paintOffset());
2035             if (layoutState->isClipped())
2036                 rect.intersect(layoutState->clipRect());
2037             return;
2038         }
2039     }
2040
2041     if (hasReflection())
2042         rect.unite(reflectedRect(rect));
2043
2044     if (paintInvalidationContainer == this) {
2045         if (paintInvalidationContainer->style()->isFlippedBlocksWritingMode())
2046             flipForWritingMode(rect);
2047         return;
2048     }
2049
2050     bool containerSkipped;
2051     RenderObject* o = container(paintInvalidationContainer, &containerSkipped);
2052     if (!o)
2053         return;
2054
2055     if (isWritingModeRoot() && !isOutOfFlowPositioned())
2056         flipForWritingMode(rect);
2057
2058     LayoutPoint topLeft = rect.location();
2059     topLeft.move(locationOffset());
2060
2061     EPosition position = styleToUse->position();
2062
2063     // We are now in our parent container's coordinate space.  Apply our transform to obtain a bounding box
2064     // in the parent's coordinate space that encloses us.
2065     if (hasLayer() && layer()->transform()) {
2066         fixed = position == FixedPosition;
2067         rect = layer()->transform()->mapRect(pixelSnappedIntRect(rect));
2068         topLeft = rect.location();
2069         topLeft.move(locationOffset());
2070     } else if (position == FixedPosition)
2071         fixed = true;
2072
2073     if (position == AbsolutePosition && o->isInFlowPositioned() && o->isRenderInline()) {
2074         topLeft += toRenderInline(o)->offsetForInFlowPositionedInline(*this);
2075     } else if (styleToUse->hasInFlowPosition() && layer()) {
2076         // Apply the relative position offset when invalidating a rectangle.  The layer
2077         // is translated, but the render box isn't, so we need to do this to get the
2078         // right dirty rect.  Since this is called from RenderObject::setStyle, the relative position
2079         // flag on the RenderObject has been cleared, so use the one on the style().
2080         topLeft += layer()->offsetForInFlowPosition();
2081     }
2082
2083     if (position != AbsolutePosition && position != FixedPosition && o->hasColumns() && o->isRenderBlockFlow()) {
2084         LayoutRect repaintRect(topLeft, rect.size());
2085         toRenderBlock(o)->adjustRectForColumns(repaintRect);
2086         topLeft = repaintRect.location();
2087         rect = repaintRect;
2088     }
2089
2090     // FIXME: We ignore the lightweight clipping rect that controls use, since if |o| is in mid-layout,
2091     // its controlClipRect will be wrong. For overflow clip we use the values cached by the layer.
2092     rect.setLocation(topLeft);
2093     if (o->hasOverflowClip()) {
2094         RenderBox* containerBox = toRenderBox(o);
2095         containerBox->applyCachedClipAndScrollOffsetForRepaint(rect);
2096         if (rect.isEmpty())
2097             return;
2098     }
2099
2100     if (containerSkipped) {
2101         // If the paintInvalidationContainer is below o, then we need to map the rect into paintInvalidationContainer's coordinates.
2102         LayoutSize containerOffset = paintInvalidationContainer->offsetFromAncestorContainer(o);
2103         rect.move(-containerOffset);
2104         return;
2105     }
2106
2107     o->mapRectToPaintInvalidationBacking(paintInvalidationContainer, rect, fixed);
2108 }
2109
2110 void RenderBox::repaintDuringLayoutIfMoved(const LayoutRect& oldRect)
2111 {
2112     if (oldRect.location() != m_frameRect.location()) {
2113         LayoutRect newRect = m_frameRect;
2114         // The child moved.  Invalidate the object's old and new positions.  We have to do this
2115         // since the object may not have gotten a layout.
2116         m_frameRect = oldRect;
2117         paintInvalidationForWholeRenderer();
2118         repaintOverhangingFloats(true);
2119         m_frameRect = newRect;
2120         paintInvalidationForWholeRenderer();
2121         repaintOverhangingFloats(true);
2122     }
2123 }
2124
2125 void RenderBox::repaintOverhangingFloats(bool)
2126 {
2127 }
2128
2129 void RenderBox::updateLogicalWidth()
2130 {
2131     LogicalExtentComputedValues computedValues;
2132     computeLogicalWidth(computedValues);
2133
2134     setLogicalWidth(computedValues.m_extent);
2135     setLogicalLeft(computedValues.m_position);
2136     setMarginStart(computedValues.m_margins.m_start);
2137     setMarginEnd(computedValues.m_margins.m_end);
2138 }
2139
2140 static float getMaxWidthListMarker(const RenderBox* renderer)
2141 {
2142 #ifndef NDEBUG
2143     ASSERT(renderer);
2144     Node* parentNode = renderer->generatingNode();
2145     ASSERT(parentNode);
2146     ASSERT(isHTMLOListElement(parentNode) || isHTMLUListElement(parentNode));
2147     ASSERT(renderer->style()->textAutosizingMultiplier() != 1);
2148 #endif
2149     float maxWidth = 0;
2150     for (RenderObject* child = renderer->slowFirstChild(); child; child = child->nextSibling()) {
2151         if (!child->isListItem())
2152             continue;
2153
2154         RenderBox* listItem = toRenderBox(child);
2155         for (RenderObject* itemChild = listItem->slowFirstChild(); itemChild; itemChild = itemChild->nextSibling()) {
2156             if (!itemChild->isListMarker())
2157                 continue;
2158             RenderBox* itemMarker = toRenderBox(itemChild);
2159             // Make sure to compute the autosized width.
2160             if (itemMarker->needsLayout())
2161                 itemMarker->layout();
2162             maxWidth = max<float>(maxWidth, toRenderListMarker(itemMarker)->logicalWidth().toFloat());
2163             break;
2164         }
2165     }
2166     return maxWidth;
2167 }
2168
2169 void RenderBox::computeLogicalWidth(LogicalExtentComputedValues& computedValues) const
2170 {
2171     computedValues.m_extent = logicalWidth();
2172     computedValues.m_position = logicalLeft();
2173     computedValues.m_margins.m_start = marginStart();
2174     computedValues.m_margins.m_end = marginEnd();
2175
2176     if (isOutOfFlowPositioned()) {
2177         // FIXME: This calculation is not patched for block-flow yet.
2178         // https://bugs.webkit.org/show_bug.cgi?id=46500
2179         computePositionedLogicalWidth(computedValues);
2180         return;
2181     }
2182
2183     // If layout is limited to a subtree, the subtree root's logical width does not change.
2184     if (node() && view()->frameView() && view()->frameView()->layoutRoot(true) == this)
2185         return;
2186
2187     // The parent box is flexing us, so it has increased or decreased our
2188     // width.  Use the width from the style context.
2189     // FIXME: Account for block-flow in flexible boxes.
2190     // https://bugs.webkit.org/show_bug.cgi?id=46418
2191     if (hasOverrideWidth() && (style()->borderFit() == BorderFitLines || parent()->isFlexibleBoxIncludingDeprecated())) {
2192         computedValues.m_extent = overrideLogicalContentWidth() + borderAndPaddingLogicalWidth();
2193         return;
2194     }
2195
2196     // FIXME: Account for block-flow in flexible boxes.
2197     // https://bugs.webkit.org/show_bug.cgi?id=46418
2198     bool inVerticalBox = parent()->isDeprecatedFlexibleBox() && (parent()->style()->boxOrient() == VERTICAL);
2199     bool stretching = (parent()->style()->boxAlign() == BSTRETCH);
2200     bool treatAsReplaced = shouldComputeSizeAsReplaced() && (!inVerticalBox || !stretching);
2201
2202     RenderStyle* styleToUse = style();
2203     Length logicalWidthLength = treatAsReplaced ? Length(computeReplacedLogicalWidth(), Fixed) : styleToUse->logicalWidth();
2204
2205     RenderBlock* cb = containingBlock();
2206     LayoutUnit containerLogicalWidth = max<LayoutUnit>(0, containingBlockLogicalWidthForContent());
2207     bool hasPerpendicularContainingBlock = cb->isHorizontalWritingMode() != isHorizontalWritingMode();
2208
2209     if (isInline() && !isInlineBlockOrInlineTable()) {
2210         // just calculate margins
2211         computedValues.m_margins.m_start = minimumValueForLength(styleToUse->marginStart(), containerLogicalWidth);
2212         computedValues.m_margins.m_end = minimumValueForLength(styleToUse->marginEnd(), containerLogicalWidth);
2213         if (treatAsReplaced)
2214             computedValues.m_extent = max<LayoutUnit>(floatValueForLength(logicalWidthLength, 0) + borderAndPaddingLogicalWidth(), minPreferredLogicalWidth());
2215         return;
2216     }
2217
2218     // Width calculations
2219     if (treatAsReplaced)
2220         computedValues.m_extent = logicalWidthLength.value() + borderAndPaddingLogicalWidth();
2221     else {
2222         LayoutUnit containerWidthInInlineDirection = containerLogicalWidth;
2223         if (hasPerpendicularContainingBlock)
2224             containerWidthInInlineDirection = perpendicularContainingBlockLogicalHeight();
2225         LayoutUnit preferredWidth = computeLogicalWidthUsing(MainOrPreferredSize, styleToUse->logicalWidth(), containerWidthInInlineDirection, cb);
2226         computedValues.m_extent = constrainLogicalWidthByMinMax(preferredWidth, containerWidthInInlineDirection, cb);
2227     }
2228
2229     // Margin calculations.
2230     computeMarginsForDirection(InlineDirection, cb, containerLogicalWidth, computedValues.m_extent, computedValues.m_margins.m_start,
2231         computedValues.m_margins.m_end, style()->marginStart(), style()->marginEnd());
2232
2233     if (!hasPerpendicularContainingBlock && containerLogicalWidth && containerLogicalWidth != (computedValues.m_extent + computedValues.m_margins.m_start + computedValues.m_margins.m_end)
2234         && !isFloating() && !isInline() && !cb->isFlexibleBoxIncludingDeprecated() && !cb->isRenderGrid()) {
2235         LayoutUnit newMargin = containerLogicalWidth - computedValues.m_extent - cb->marginStartForChild(this);
2236         bool hasInvertedDirection = cb->style()->isLeftToRightDirection() != style()->isLeftToRightDirection();
2237         if (hasInvertedDirection)
2238             computedValues.m_margins.m_start = newMargin;
2239         else
2240             computedValues.m_margins.m_end = newMargin;
2241     }
2242
2243     if (styleToUse->textAutosizingMultiplier() != 1 && styleToUse->marginStart().type() == Fixed) {
2244         Node* parentNode = generatingNode();
2245         if (parentNode && (isHTMLOListElement(*parentNode) || isHTMLUListElement(*parentNode))) {
2246             // Make sure the markers in a list are properly positioned (i.e. not chopped off) when autosized.
2247             const float adjustedMargin = (1 - 1.0 / styleToUse->textAutosizingMultiplier()) * getMaxWidthListMarker(this);
2248             bool hasInvertedDirection = cb->style()->isLeftToRightDirection() != style()->isLeftToRightDirection();
2249             if (hasInvertedDirection)
2250                 computedValues.m_margins.m_end += adjustedMargin;
2251             else
2252                 computedValues.m_margins.m_start += adjustedMargin;
2253         }
2254     }
2255 }
2256
2257 LayoutUnit RenderBox::fillAvailableMeasure(LayoutUnit availableLogicalWidth) const
2258 {
2259     LayoutUnit marginStart = 0;
2260     LayoutUnit marginEnd = 0;
2261     return fillAvailableMeasure(availableLogicalWidth, marginStart, marginEnd);
2262 }
2263
2264 LayoutUnit RenderBox::fillAvailableMeasure(LayoutUnit availableLogicalWidth, LayoutUnit& marginStart, LayoutUnit& marginEnd) const
2265 {
2266     marginStart = minimumValueForLength(style()->marginStart(), availableLogicalWidth);
2267     marginEnd = minimumValueForLength(style()->marginEnd(), availableLogicalWidth);
2268     return availableLogicalWidth - marginStart - marginEnd;
2269 }
2270
2271 LayoutUnit RenderBox::computeIntrinsicLogicalWidthUsing(const Length& logicalWidthLength, LayoutUnit availableLogicalWidth, LayoutUnit borderAndPadding) const
2272 {
2273     if (logicalWidthLength.type() == FillAvailable)
2274         return fillAvailableMeasure(availableLogicalWidth);
2275
2276     LayoutUnit minLogicalWidth = 0;
2277     LayoutUnit maxLogicalWidth = 0;
2278     computeIntrinsicLogicalWidths(minLogicalWidth, maxLogicalWidth);
2279
2280     if (logicalWidthLength.type() == MinContent)
2281         return minLogicalWidth + borderAndPadding;
2282
2283     if (logicalWidthLength.type() == MaxContent)
2284         return maxLogicalWidth + borderAndPadding;
2285
2286     if (logicalWidthLength.type() == FitContent) {
2287         minLogicalWidth += borderAndPadding;
2288         maxLogicalWidth += borderAndPadding;
2289         return max(minLogicalWidth, min(maxLogicalWidth, fillAvailableMeasure(availableLogicalWidth)));
2290     }
2291
2292     ASSERT_NOT_REACHED();
2293     return 0;
2294 }
2295
2296 LayoutUnit RenderBox::computeLogicalWidthUsing(SizeType widthType, const Length& logicalWidth, LayoutUnit availableLogicalWidth, const RenderBlock* cb) const
2297 {
2298     if (!logicalWidth.isIntrinsicOrAuto()) {
2299         // FIXME: If the containing block flow is perpendicular to our direction we need to use the available logical height instead.
2300         return adjustBorderBoxLogicalWidthForBoxSizing(valueForLength(logicalWidth, availableLogicalWidth));
2301     }
2302
2303     if (logicalWidth.isIntrinsic())
2304         return computeIntrinsicLogicalWidthUsing(logicalWidth, availableLogicalWidth, borderAndPaddingLogicalWidth());
2305
2306     LayoutUnit marginStart = 0;
2307     LayoutUnit marginEnd = 0;
2308     LayoutUnit logicalWidthResult = fillAvailableMeasure(availableLogicalWidth, marginStart, marginEnd);
2309
2310     if (shrinkToAvoidFloats() && cb->containsFloats())
2311         logicalWidthResult = min(logicalWidthResult, shrinkLogicalWidthToAvoidFloats(marginStart, marginEnd, toRenderBlockFlow(cb)));
2312
2313     if (widthType == MainOrPreferredSize && sizesLogicalWidthToFitContent(logicalWidth))
2314         return max(minPreferredLogicalWidth(), min(maxPreferredLogicalWidth(), logicalWidthResult));
2315     return logicalWidthResult;
2316 }
2317
2318 static bool columnFlexItemHasStretchAlignment(const RenderObject* flexitem)
2319 {
2320     RenderObject* parent = flexitem->parent();
2321     // auto margins mean we don't stretch. Note that this function will only be used for
2322     // widths, so we don't have to check marginBefore/marginAfter.
2323     ASSERT(parent->style()->isColumnFlexDirection());
2324     if (flexitem->style()->marginStart().isAuto() || flexitem->style()->marginEnd().isAuto())
2325         return false;
2326     return flexitem->style()->alignSelf() == ItemPositionStretch || (flexitem->style()->alignSelf() == ItemPositionAuto && parent->style()->alignItems() == ItemPositionStretch);
2327 }
2328
2329 static bool isStretchingColumnFlexItem(const RenderObject* flexitem)
2330 {
2331     RenderObject* parent = flexitem->parent();
2332     if (parent->isDeprecatedFlexibleBox() && parent->style()->boxOrient() == VERTICAL && parent->style()->boxAlign() == BSTRETCH)
2333         return true;
2334
2335     // We don't stretch multiline flexboxes because they need to apply line spacing (align-content) first.
2336     if (parent->isFlexibleBox() && parent->style()->flexWrap() == FlexNoWrap && parent->style()->isColumnFlexDirection() && columnFlexItemHasStretchAlignment(flexitem))
2337         return true;
2338     return false;
2339 }
2340
2341 bool RenderBox::sizesLogicalWidthToFitContent(const Length& logicalWidth) const
2342 {
2343     // Marquees in WinIE are like a mixture of blocks and inline-blocks.  They size as though they're blocks,
2344     // but they allow text to sit on the same line as the marquee.
2345     if (isFloating() || (isInlineBlockOrInlineTable() && !isMarquee()))
2346         return true;
2347
2348     if (logicalWidth.type() == Intrinsic)
2349         return true;
2350
2351     // Children of a horizontal marquee do not fill the container by default.
2352     // FIXME: Need to deal with MAUTO value properly.  It could be vertical.
2353     // FIXME: Think about block-flow here.  Need to find out how marquee direction relates to
2354     // block-flow (as well as how marquee overflow should relate to block flow).
2355     // https://bugs.webkit.org/show_bug.cgi?id=46472
2356     if (parent()->isMarquee()) {
2357         EMarqueeDirection dir = parent()->style()->marqueeDirection();
2358         if (dir == MAUTO || dir == MFORWARD || dir == MBACKWARD || dir == MLEFT || dir == MRIGHT)
2359             return true;
2360     }
2361
2362     // Flexible box items should shrink wrap, so we lay them out at their intrinsic widths.
2363     // In the case of columns that have a stretch alignment, we go ahead and layout at the
2364     // stretched size to avoid an extra layout when applying alignment.
2365     if (parent()->isFlexibleBox()) {
2366         // For multiline columns, we need to apply align-content first, so we can't stretch now.
2367         if (!parent()->style()->isColumnFlexDirection() || parent()->style()->flexWrap() != FlexNoWrap)
2368             return true;
2369         if (!columnFlexItemHasStretchAlignment(this))
2370             return true;
2371     }
2372
2373     // Flexible horizontal boxes lay out children at their intrinsic widths.  Also vertical boxes
2374     // that don't stretch their kids lay out their children at their intrinsic widths.
2375     // FIXME: Think about block-flow here.
2376     // https://bugs.webkit.org/show_bug.cgi?id=46473
2377     if (parent()->isDeprecatedFlexibleBox() && (parent()->style()->boxOrient() == HORIZONTAL || parent()->style()->boxAlign() != BSTRETCH))
2378         return true;
2379
2380     // Button, input, select, textarea, and legend treat width value of 'auto' as 'intrinsic' unless it's in a
2381     // stretching column flexbox.
2382     // FIXME: Think about block-flow here.
2383     // https://bugs.webkit.org/show_bug.cgi?id=46473
2384     if (logicalWidth.isAuto() && !isStretchingColumnFlexItem(this) && autoWidthShouldFitContent())
2385         return true;
2386
2387     if (isHorizontalWritingMode() != containingBlock()->isHorizontalWritingMode())
2388         return true;
2389
2390     return false;
2391 }
2392
2393 bool RenderBox::autoWidthShouldFitContent() const
2394 {
2395     return node() && (isHTMLInputElement(*node()) || isHTMLSelectElement(*node()) || isHTMLButtonElement(*node())
2396         || isHTMLTextAreaElement(*node()) || (isHTMLLegendElement(*node()) && !style()->hasOutOfFlowPosition()));
2397 }
2398
2399 void RenderBox::computeMarginsForDirection(MarginDirection flowDirection, const RenderBlock* containingBlock, LayoutUnit containerWidth, LayoutUnit childWidth, LayoutUnit& marginStart, LayoutUnit& marginEnd, Length marginStartLength, Length marginEndLength) const
2400 {
2401     if (flowDirection == BlockDirection || isFloating() || isInline()) {
2402         if (isTableCell() && flowDirection == BlockDirection) {
2403             // FIXME: Not right if we allow cells to have different directionality than the table. If we do allow this, though,
2404             // we may just do it with an extra anonymous block inside the cell.
2405             marginStart = 0;
2406             marginEnd = 0;
2407             return;
2408         }
2409
2410         // Margins are calculated with respect to the logical width of
2411         // the containing block (8.3)
2412         // Inline blocks/tables and floats don't have their margins increased.
2413         marginStart = minimumValueForLength(marginStartLength, containerWidth);
2414         marginEnd = minimumValueForLength(marginEndLength, containerWidth);
2415         return;
2416     }
2417
2418     if (containingBlock->isFlexibleBox()) {
2419         // We need to let flexbox handle the margin adjustment - otherwise, flexbox
2420         // will think we're wider than we actually are and calculate line sizes wrong.
2421         // See also http://dev.w3.org/csswg/css-flexbox/#auto-margins
2422         if (marginStartLength.isAuto())
2423             marginStartLength.setValue(0);
2424         if (marginEndLength.isAuto())
2425             marginEndLength.setValue(0);
2426     }
2427
2428     LayoutUnit marginStartWidth = minimumValueForLength(marginStartLength, containerWidth);
2429     LayoutUnit marginEndWidth = minimumValueForLength(marginEndLength, containerWidth);
2430
2431     LayoutUnit availableWidth = containerWidth;
2432     if (avoidsFloats() && containingBlock->containsFloats()) {
2433         availableWidth = containingBlockAvailableLineWidth();
2434         if (shrinkToAvoidFloats() && availableWidth < containerWidth) {
2435             marginStart = max<LayoutUnit>(0, marginStartWidth);
2436             marginEnd = max<LayoutUnit>(0, marginEndWidth);
2437         }
2438     }
2439
2440     // CSS 2.1 (10.3.3): "If 'width' is not 'auto' and 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width'
2441     // (plus any of 'margin-left' or 'margin-right' that are not 'auto') is larger than the width of the containing block, then any 'auto'
2442     // values for 'margin-left' or 'margin-right' are, for the following rules, treated as zero.
2443     LayoutUnit marginBoxWidth = childWidth + (!style()->width().isAuto() ? marginStartWidth + marginEndWidth : LayoutUnit());
2444
2445     // CSS 2.1: "If both 'margin-left' and 'margin-right' are 'auto', their used values are equal. This horizontally centers the element
2446     // with respect to the edges of the containing block."
2447     const RenderStyle* containingBlockStyle = containingBlock->style();
2448     if ((marginStartLength.isAuto() && marginEndLength.isAuto() && marginBoxWidth < availableWidth)
2449         || (!marginStartLength.isAuto() && !marginEndLength.isAuto() && containingBlockStyle->textAlign() == WEBKIT_CENTER)) {
2450         // Other browsers center the margin box for align=center elements so we match them here.
2451         LayoutUnit centeredMarginBoxStart = max<LayoutUnit>(0, (availableWidth - childWidth - marginStartWidth - marginEndWidth) / 2);
2452         marginStart = centeredMarginBoxStart + marginStartWidth;
2453         marginEnd = availableWidth - childWidth - marginStart + marginEndWidth;
2454         return;
2455     }
2456
2457     // CSS 2.1: "If there is exactly one value specified as 'auto', its used value follows from the equality."
2458     if (marginEndLength.isAuto() && marginBoxWidth < availableWidth) {
2459         marginStart = marginStartWidth;
2460         marginEnd = availableWidth - childWidth - marginStart;
2461         return;
2462     }
2463
2464     bool pushToEndFromTextAlign = !marginEndLength.isAuto() && ((!containingBlockStyle->isLeftToRightDirection() && containingBlockStyle->textAlign() == WEBKIT_LEFT)
2465         || (containingBlockStyle->isLeftToRightDirection() && containingBlockStyle->textAlign() == WEBKIT_RIGHT));
2466     if ((marginStartLength.isAuto() && marginBoxWidth < availableWidth) || pushToEndFromTextAlign) {
2467         marginEnd = marginEndWidth;
2468         marginStart = availableWidth - childWidth - marginEnd;
2469         return;
2470     }
2471
2472     // Either no auto margins, or our margin box width is >= the container width, auto margins will just turn into 0.
2473     marginStart = marginStartWidth;
2474     marginEnd = marginEndWidth;
2475 }
2476
2477 void RenderBox::updateLogicalHeight()
2478 {
2479     m_intrinsicContentLogicalHeight = contentLogicalHeight();
2480
2481     LogicalExtentComputedValues computedValues;
2482     computeLogicalHeight(logicalHeight(), logicalTop(), computedValues);
2483
2484     setLogicalHeight(computedValues.m_extent);
2485     setLogicalTop(computedValues.m_position);
2486     setMarginBefore(computedValues.m_margins.m_before);
2487     setMarginAfter(computedValues.m_margins.m_after);
2488 }
2489
2490 void RenderBox::computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues& computedValues) const
2491 {
2492     computedValues.m_extent = logicalHeight;
2493     computedValues.m_position = logicalTop;
2494
2495     // Cell height is managed by the table and inline non-replaced elements do not support a height property.
2496     if (isTableCell() || (isInline() && !isReplaced()))
2497         return;
2498
2499     Length h;
2500     if (isOutOfFlowPositioned())
2501         computePositionedLogicalHeight(computedValues);
2502     else {
2503         RenderBlock* cb = containingBlock();
2504
2505         // If we are perpendicular to our containing block then we need to resolve our block-start and block-end margins so that if they
2506         // are 'auto' we are centred or aligned within the inline flow containing block: this is done by computing the margins as though they are inline.
2507         // Note that as this is the 'sizing phase' we are using our own writing mode rather than the containing block's. We use the containing block's
2508         // writing mode when figuring out the block-direction margins for positioning in |computeAndSetBlockDirectionMargins| (i.e. margin collapsing etc.).
2509         // See http://www.w3.org/TR/2014/CR-css-writing-modes-3-20140320/#orthogonal-flows
2510         MarginDirection flowDirection = isHorizontalWritingMode() != cb->isHorizontalWritingMode() ? InlineDirection : BlockDirection;
2511
2512         // For tables, calculate margins only.
2513         if (isTable()) {
2514             // FIXME: RenderTable::layout() calls updateLogicalHeight() when an empty table has no height yet, so auto margins can come out wrong here when
2515             // we are perpendicular to our containing block.
2516             computeMarginsForDirection(flowDirection, cb, containingBlockLogicalWidthForContent(), computedValues.m_extent, computedValues.m_margins.m_before,
2517                 computedValues.m_margins.m_after, style()->marginBefore(), style()->marginAfter());
2518             return;
2519         }
2520
2521         // FIXME: Account for block-flow in flexible boxes.
2522         // https://bugs.webkit.org/show_bug.cgi?id=46418
2523         bool inHorizontalBox = parent()->isDeprecatedFlexibleBox() && parent()->style()->boxOrient() == HORIZONTAL;
2524         bool stretching = parent()->style()->boxAlign() == BSTRETCH;
2525         bool treatAsReplaced = shouldComputeSizeAsReplaced() && (!inHorizontalBox || !stretching);
2526         bool checkMinMaxHeight = false;
2527
2528         // The parent box is flexing us, so it has increased or decreased our height.  We have to
2529         // grab our cached flexible height.
2530         // FIXME: Account for block-flow in flexible boxes.
2531         // https://bugs.webkit.org/show_bug.cgi?id=46418
2532         if (hasOverrideHeight() && parent()->isFlexibleBoxIncludingDeprecated())
2533             h = Length(overrideLogicalContentHeight(), Fixed);
2534         else if (treatAsReplaced)
2535             h = Length(computeReplacedLogicalHeight(), Fixed);
2536         else {
2537             h = style()->logicalHeight();
2538             checkMinMaxHeight = true;
2539         }
2540
2541         // Block children of horizontal flexible boxes fill the height of the box.
2542         // FIXME: Account for block-flow in flexible boxes.
2543         // https://bugs.webkit.org/show_bug.cgi?id=46418
2544         if (h.isAuto() && inHorizontalBox && toRenderDeprecatedFlexibleBox(parent())->isStretchingChildren()) {
2545             h = Length(parentBox()->contentLogicalHeight() - marginBefore() - marginAfter() - borderAndPaddingLogicalHeight(), Fixed);
2546             checkMinMaxHeight = false;
2547         }
2548
2549         LayoutUnit heightResult;
2550         if (checkMinMaxHeight) {
2551             heightResult = computeLogicalHeightUsing(style()->logicalHeight(), computedValues.m_extent - borderAndPaddingLogicalHeight());
2552             if (heightResult == -1)
2553                 heightResult = computedValues.m_extent;
2554             heightResult = constrainLogicalHeightByMinMax(heightResult, computedValues.m_extent - borderAndPaddingLogicalHeight());
2555         } else {
2556             // The only times we don't check min/max height are when a fixed length has
2557             // been given as an override.  Just use that.  The value has already been adjusted
2558             // for box-sizing.
2559             ASSERT(h.isFixed());
2560             heightResult = h.value() + borderAndPaddingLogicalHeight();
2561         }
2562
2563         computedValues.m_extent = heightResult;
2564         computeMarginsForDirection(flowDirection, cb, containingBlockLogicalWidthForContent(), computedValues.m_extent, computedValues.m_margins.m_before,
2565             computedValues.m_margins.m_after, style()->marginBefore(), style()->marginAfter());
2566     }
2567
2568     // WinIE quirk: The <html> block always fills the entire canvas in quirks mode.  The <body> always fills the
2569     // <html> block in quirks mode.  Only apply this quirk if the block is normal flow and no height
2570     // is specified. When we're printing, we also need this quirk if the body or root has a percentage
2571     // height since we don't set a height in RenderView when we're printing. So without this quirk, the
2572     // height has nothing to be a percentage of, and it ends up being 0. That is bad.
2573     bool paginatedContentNeedsBaseHeight = document().printing() && h.isPercent()
2574         && (isDocumentElement() || (isBody() && document().documentElement()->renderer()->style()->logicalHeight().isPercent())) && !isInline();
2575     if (stretchesToViewport() || paginatedContentNeedsBaseHeight) {
2576         LayoutUnit margins = collapsedMarginBefore() + collapsedMarginAfter();
2577         LayoutUnit visibleHeight = view()->viewLogicalHeightForPercentages();
2578         if (isDocumentElement())
2579             computedValues.m_extent = max(computedValues.m_extent, visibleHeight - margins);
2580         else {
2581             LayoutUnit marginsBordersPadding = margins + parentBox()->marginBefore() + parentBox()->marginAfter() + parentBox()->borderAndPaddingLogicalHeight();
2582             computedValues.m_extent = max(computedValues.m_extent, visibleHeight - marginsBordersPadding);
2583         }
2584     }
2585 }
2586
2587 LayoutUnit RenderBox::computeLogicalHeightUsing(const Length& height, LayoutUnit intrinsicContentHeight) const
2588 {
2589     LayoutUnit logicalHeight = computeContentAndScrollbarLogicalHeightUsing(height, intrinsicContentHeight);
2590     if (logicalHeight != -1)
2591         logicalHeight = adjustBorderBoxLogicalHeightForBoxSizing(logicalHeight);
2592     return logicalHeight;
2593 }
2594
2595 LayoutUnit RenderBox::computeContentLogicalHeight(const Length& height, LayoutUnit intrinsicContentHeight) const
2596 {
2597     LayoutUnit heightIncludingScrollbar = computeContentAndScrollbarLogicalHeightUsing(height, intrinsicContentHeight);
2598     if (heightIncludingScrollbar == -1)
2599         return -1;
2600     return std::max<LayoutUnit>(0, adjustContentBoxLogicalHeightForBoxSizing(heightIncludingScrollbar) - scrollbarLogicalHeight());
2601 }
2602
2603 LayoutUnit RenderBox::computeIntrinsicLogicalContentHeightUsing(const Length& logicalHeightLength, LayoutUnit intrinsicContentHeight, LayoutUnit borderAndPadding) const
2604 {
2605     // FIXME(cbiesinger): The css-sizing spec is considering changing what min-content/max-content should resolve to.
2606     // If that happens, this code will have to change.
2607     if (logicalHeightLength.isMinContent() || logicalHeightLength.isMaxContent() || logicalHeightLength.isFitContent()) {
2608         if (isReplaced())
2609             return intrinsicSize().height();
2610         if (m_intrinsicContentLogicalHeight != -1)
2611             return m_intrinsicContentLogicalHeight;
2612         return intrinsicContentHeight;
2613     }
2614     if (logicalHeightLength.isFillAvailable())
2615         return containingBlock()->availableLogicalHeight(ExcludeMarginBorderPadding) - borderAndPadding;
2616     ASSERT_NOT_REACHED();
2617     return 0;
2618 }
2619
2620 LayoutUnit RenderBox::computeContentAndScrollbarLogicalHeightUsing(const Length& height, LayoutUnit intrinsicContentHeight) const
2621 {
2622     // FIXME(cbiesinger): The css-sizing spec is considering changing what min-content/max-content should resolve to.
2623     // If that happens, this code will have to change.
2624     if (height.isIntrinsic()) {
2625         if (intrinsicContentHeight == -1)
2626             return -1; // Intrinsic height isn't available.
2627         return computeIntrinsicLogicalContentHeightUsing(height, intrinsicContentHeight, borderAndPaddingLogicalHeight());
2628     }
2629     if (height.isFixed())
2630         return height.value();
2631     if (height.isPercent())
2632         return computePercentageLogicalHeight(height);
2633     return -1;
2634 }
2635
2636 bool RenderBox::skipContainingBlockForPercentHeightCalculation(const RenderBox* containingBlock) const
2637 {
2638     // Flow threads for multicol or paged overflow should be skipped. They are invisible to the DOM,
2639     // and percent heights of children should be resolved against the multicol or paged container.
2640     if (containingBlock->isRenderFlowThread())
2641         return true;
2642
2643     // For quirks mode and anonymous blocks, we skip auto-height containingBlocks when computing percentages.
2644     // For standards mode, we treat the percentage as auto if it has an auto-height containing block.
2645     if (!document().inQuirksMode() && !containingBlock->isAnonymousBlock())
2646         return false;
2647     return !containingBlock->isTableCell() && !containingBlock->isOutOfFlowPositioned() && containingBlock->style()->logicalHeight().isAuto() && isHorizontalWritingMode() == containingBlock->isHorizontalWritingMode();
2648 }
2649
2650 LayoutUnit RenderBox::computePercentageLogicalHeight(const Length& height) const
2651 {
2652     LayoutUnit availableHeight = -1;
2653
2654     bool skippedAutoHeightContainingBlock = false;
2655     RenderBlock* cb = containingBlock();
2656     const RenderBox* containingBlockChild = this;
2657     LayoutUnit rootMarginBorderPaddingHeight = 0;
2658     while (!cb->isRenderView() && skipContainingBlockForPercentHeightCalculation(cb)) {
2659         if (cb->isBody() || cb->isDocumentElement())
2660             rootMarginBorderPaddingHeight += cb->marginBefore() + cb->marginAfter() + cb->borderAndPaddingLogicalHeight();
2661         skippedAutoHeightContainingBlock = true;
2662         containingBlockChild = cb;
2663         cb = cb->containingBlock();
2664     }
2665     cb->addPercentHeightDescendant(const_cast<RenderBox*>(this));
2666
2667     RenderStyle* cbstyle = cb->style();
2668
2669     // A positioned element that specified both top/bottom or that specifies height should be treated as though it has a height
2670     // explicitly specified that can be used for any percentage computations.
2671     bool isOutOfFlowPositionedWithSpecifiedHeight = cb->isOutOfFlowPositioned() && (!cbstyle->logicalHeight().isAuto() || (!cbstyle->logicalTop().isAuto() && !cbstyle->logicalBottom().isAuto()));
2672
2673     bool includeBorderPadding = isTable();
2674
2675     if (isHorizontalWritingMode() != cb->isHorizontalWritingMode())
2676         availableHeight = containingBlockChild->containingBlockLogicalWidthForContent();
2677     else if (hasOverrideContainingBlockLogicalHeight())
2678         availableHeight = overrideContainingBlockContentLogicalHeight();
2679     else if (cb->isTableCell()) {
2680         if (!skippedAutoHeightContainingBlock) {
2681             // Table cells violate what the CSS spec says to do with heights. Basically we
2682             // don't care if the cell specified a height or not. We just always make ourselves
2683             // be a percentage of the cell's current content height.
2684             if (!cb->hasOverrideHeight()) {
2685                 // Normally we would let the cell size intrinsically, but scrolling overflow has to be
2686                 // treated differently, since WinIE lets scrolled overflow regions shrink as needed.
2687                 // While we can't get all cases right, we can at least detect when the cell has a specified
2688                 // height or when the table has a specified height. In these cases we want to initially have
2689                 // no size and allow the flexing of the table or the cell to its specified height to cause us
2690                 // to grow to fill the space. This could end up being wrong in some cases, but it is
2691                 // preferable to the alternative (sizing intrinsically and making the row end up too big).
2692                 RenderTableCell* cell = toRenderTableCell(cb);
2693                 if (scrollsOverflowY() && (!cell->style()->logicalHeight().isAuto() || !cell->table()->style()->logicalHeight().isAuto()))
2694                     return 0;
2695                 return -1;
2696             }
2697             availableHeight = cb->overrideLogicalContentHeight();
2698             includeBorderPadding = true;
2699         }
2700     } else if (cbstyle->logicalHeight().isFixed()) {
2701         LayoutUnit contentBoxHeight = cb->adjustContentBoxLogicalHeightForBoxSizing(cbstyle->logicalHeight().value());
2702         availableHeight = max<LayoutUnit>(0, cb->constrainContentBoxLogicalHeightByMinMax(contentBoxHeight - cb->scrollbarLogicalHeight(), -1));
2703     } else if (cbstyle->logicalHeight().isPercent() && !isOutOfFlowPositionedWithSpecifiedHeight) {
2704         // We need to recur and compute the percentage height for our containing block.
2705         LayoutUnit heightWithScrollbar = cb->computePercentageLogicalHeight(cbstyle->logicalHeight());
2706         if (heightWithScrollbar != -1) {
2707             LayoutUnit contentBoxHeightWithScrollbar = cb->adjustContentBoxLogicalHeightForBoxSizing(heightWithScrollbar);
2708             // We need to adjust for min/max height because this method does not
2709             // handle the min/max of the current block, its caller does. So the
2710             // return value from the recursive call will not have been adjusted
2711             // yet.
2712             LayoutUnit contentBoxHeight = cb->constrainContentBoxLogicalHeightByMinMax(contentBoxHeightWithScrollbar - cb->scrollbarLogicalHeight(), -1);
2713             availableHeight = max<LayoutUnit>(0, contentBoxHeight);
2714         }
2715     } else if (isOutOfFlowPositionedWithSpecifiedHeight) {
2716         // Don't allow this to affect the block' height() member variable, since this
2717         // can get called while the block is still laying out its kids.
2718         LogicalExtentComputedValues computedValues;
2719         cb->computeLogicalHeight(cb->logicalHeight(), 0, computedValues);
2720         availableHeight = computedValues.m_extent - cb->borderAndPaddingLogicalHeight() - cb->scrollbarLogicalHeight();
2721     } else if (cb->isRenderView())
2722         availableHeight = view()->viewLogicalHeightForPercentages();
2723
2724     if (availableHeight == -1)
2725         return availableHeight;
2726
2727     availableHeight -= rootMarginBorderPaddingHeight;
2728
2729     LayoutUnit result = valueForLength(height, availableHeight);
2730     if (includeBorderPadding) {
2731         // FIXME: Table cells should default to box-sizing: border-box so we can avoid this hack.
2732         // It is necessary to use the border-box to match WinIE's broken
2733         // box model. This is essential for sizing inside
2734         // table cells using percentage heights.
2735         result -= borderAndPaddingLogicalHeight();
2736         return max<LayoutUnit>(0, result);
2737     }
2738     return result;
2739 }
2740
2741 LayoutUnit RenderBox::computeReplacedLogicalWidth(ShouldComputePreferred shouldComputePreferred) const
2742 {
2743     return computeReplacedLogicalWidthRespectingMinMaxWidth(computeReplacedLogicalWidthUsing(style()->logicalWidth()), shouldComputePreferred);
2744 }
2745
2746 LayoutUnit RenderBox::computeReplacedLogicalWidthRespectingMinMaxWidth(LayoutUnit logicalWidth, ShouldComputePreferred shouldComputePreferred) const
2747 {
2748     LayoutUnit minLogicalWidth = (shouldComputePreferred == ComputePreferred && style()->logicalMinWidth().isPercent()) || style()->logicalMinWidth().isUndefined() ? logicalWidth : computeReplacedLogicalWidthUsing(style()->logicalMinWidth());
2749     LayoutUnit maxLogicalWidth = (shouldComputePreferred == ComputePreferred && style()->logicalMaxWidth().isPercent()) || style()->logicalMaxWidth().isUndefined() ? logicalWidth : computeReplacedLogicalWidthUsing(style()->logicalMaxWidth());
2750     return max(minLogicalWidth, min(logicalWidth, maxLogicalWidth));
2751 }
2752
2753 LayoutUnit RenderBox::computeReplacedLogicalWidthUsing(const Length& logicalWidth) const
2754 {
2755     switch (logicalWidth.type()) {
2756         case Fixed:
2757             return adjustContentBoxLogicalWidthForBoxSizing(logicalWidth.value());
2758         case MinContent:
2759         case MaxContent: {
2760             // MinContent/MaxContent don't need the availableLogicalWidth argument.
2761             LayoutUnit availableLogicalWidth = 0;
2762             return computeIntrinsicLogicalWidthUsing(logicalWidth, availableLogicalWidth, borderAndPaddingLogicalWidth()) - borderAndPaddingLogicalWidth();
2763         }
2764         case FitContent:
2765         case FillAvailable:
2766         case Percent:
2767         case Calculated: {
2768             // FIXME: containingBlockLogicalWidthForContent() is wrong if the replaced element's block-flow is perpendicular to the
2769             // containing block's block-flow.
2770             // https://bugs.webkit.org/show_bug.cgi?id=46496
2771             const LayoutUnit cw = isOutOfFlowPositioned() ? containingBlockLogicalWidthForPositioned(toRenderBoxModelObject(container())) : containingBlockLogicalWidthForContent();
2772             Length containerLogicalWidth = containingBlock()->style()->logicalWidth();
2773             // FIXME: Handle cases when containing block width is calculated or viewport percent.
2774             // https://bugs.webkit.org/show_bug.cgi?id=91071
2775             if (logicalWidth.isIntrinsic())
2776                 return computeIntrinsicLogicalWidthUsing(logicalWidth, cw, borderAndPaddingLogicalWidth()) - borderAndPaddingLogicalWidth();
2777             if (cw > 0 || (!cw && (containerLogicalWidth.isFixed() || containerLogicalWidth.isPercent())))
2778                 return adjustContentBoxLogicalWidthForBoxSizing(minimumValueForLength(logicalWidth, cw));
2779             return 0;
2780         }
2781         case Intrinsic:
2782         case MinIntrinsic:
2783         case Auto:
2784         case Undefined:
2785             return intrinsicLogicalWidth();
2786         case ExtendToZoom:
2787         case DeviceWidth:
2788         case DeviceHeight:
2789             break;
2790     }
2791
2792     ASSERT_NOT_REACHED();
2793     return 0;
2794 }
2795
2796 LayoutUnit RenderBox::computeReplacedLogicalHeight() const
2797 {
2798     return computeReplacedLogicalHeightRespectingMinMaxHeight(computeReplacedLogicalHeightUsing(style()->logicalHeight()));
2799 }
2800
2801 LayoutUnit RenderBox::computeReplacedLogicalHeightRespectingMinMaxHeight(LayoutUnit logicalHeight) const
2802 {
2803     LayoutUnit minLogicalHeight = computeReplacedLogicalHeightUsing(style()->logicalMinHeight());
2804     LayoutUnit maxLogicalHeight = style()->logicalMaxHeight().isUndefined() ? logicalHeight : computeReplacedLogicalHeightUsing(style()->logicalMaxHeight());
2805     return max(minLogicalHeight, min(logicalHeight, maxLogicalHeight));
2806 }
2807
2808 LayoutUnit RenderBox::computeReplacedLogicalHeightUsing(const Length& logicalHeight) const
2809 {
2810     switch (logicalHeight.type()) {
2811         case Fixed:
2812             return adjustContentBoxLogicalHeightForBoxSizing(logicalHeight.value());
2813         case Percent:
2814         case Calculated:
2815         {
2816             RenderObject* cb = isOutOfFlowPositioned() ? container() : containingBlock();
2817             while (cb->isAnonymous())
2818                 cb = cb->containingBlock();
2819             if (cb->isRenderBlock())
2820                 toRenderBlock(cb)->addPercentHeightDescendant(const_cast<RenderBox*>(this));
2821
2822             // FIXME: This calculation is not patched for block-flow yet.
2823             // https://bugs.webkit.org/show_bug.cgi?id=46500
2824             if (cb->isOutOfFlowPositioned() && cb->style()->height().isAuto() && !(cb->style()->top().isAuto() || cb->style()->bottom().isAuto())) {
2825                 ASSERT_WITH_SECURITY_IMPLICATION(cb->isRenderBlock());
2826                 RenderBlock* block = toRenderBlock(cb);
2827                 LogicalExtentComputedValues computedValues;
2828                 block->computeLogicalHeight(block->logicalHeight(), 0, computedValues);
2829                 LayoutUnit newContentHeight = computedValues.m_extent - block->borderAndPaddingLogicalHeight() - block->scrollbarLogicalHeight();
2830                 LayoutUnit newHeight = block->adjustContentBoxLogicalHeightForBoxSizing(newContentHeight);
2831                 return adjustContentBoxLogicalHeightForBoxSizing(valueForLength(logicalHeight, newHeight));
2832             }
2833
2834             // FIXME: availableLogicalHeight() is wrong if the replaced element's block-flow is perpendicular to the
2835             // containing block's block-flow.
2836             // https://bugs.webkit.org/show_bug.cgi?id=46496
2837             LayoutUnit availableHeight;
2838             if (isOutOfFlowPositioned())
2839                 availableHeight = containingBlockLogicalHeightForPositioned(toRenderBoxModelObject(cb));
2840             else {
2841                 availableHeight = containingBlockLogicalHeightForContent(IncludeMarginBorderPadding);
2842                 // It is necessary to use the border-box to match WinIE's broken
2843                 // box model.  This is essential for sizing inside
2844                 // table cells using percentage heights.
2845                 // FIXME: This needs to be made block-flow-aware.  If the cell and image are perpendicular block-flows, this isn't right.
2846                 // https://bugs.webkit.org/show_bug.cgi?id=46997
2847                 while (cb && !cb->isRenderView() && (cb->style()->logicalHeight().isAuto() || cb->style()->logicalHeight().isPercent())) {
2848                     if (cb->isTableCell()) {
2849                         // Don't let table cells squeeze percent-height replaced elements
2850                         // <http://bugs.webkit.org/show_bug.cgi?id=15359>
2851                         availableHeight = max(availableHeight, intrinsicLogicalHeight());
2852                         return valueForLength(logicalHeight, availableHeight - borderAndPaddingLogicalHeight());
2853                     }
2854                     toRenderBlock(cb)->addPercentHeightDescendant(const_cast<RenderBox*>(this));
2855                     cb = cb->containingBlock();
2856                 }
2857             }
2858             return adjustContentBoxLogicalHeightForBoxSizing(valueForLength(logicalHeight, availableHeight));
2859         }
2860         case MinContent:
2861         case MaxContent:
2862         case FitContent:
2863         case FillAvailable:
2864             return adjustContentBoxLogicalHeightForBoxSizing(computeIntrinsicLogicalContentHeightUsing(logicalHeight, intrinsicLogicalHeight(), borderAndPaddingHeight()));
2865         default:
2866             return intrinsicLogicalHeight();
2867     }
2868 }
2869
2870 LayoutUnit RenderBox::availableLogicalHeight(AvailableLogicalHeightType heightType) const
2871 {
2872     return constrainLogicalHeightByMinMax(availableLogicalHeightUsing(style()->logicalHeight(), heightType), -1);
2873 }
2874
2875 LayoutUnit RenderBox::availableLogicalHeightUsing(const Length& h, AvailableLogicalHeightType heightType) const
2876 {
2877     if (isRenderView())
2878         return isHorizontalWritingMode() ? toRenderView(this)->frameView()->visibleHeight() : toRenderView(this)->frameView()->visibleWidth();
2879
2880     // We need to stop here, since we don't want to increase the height of the table
2881     // artificially.  We're going to rely on this cell getting expanded to some new
2882     // height, and then when we lay out again we'll use the calculation below.
2883     if (isTableCell() && (h.isAuto() || h.isPercent())) {
2884         if (hasOverrideHeight())
2885             return overrideLogicalContentHeight();
2886         return logicalHeight() - borderAndPaddingLogicalHeight();
2887     }
2888
2889     if (h.isPercent() && isOutOfFlowPositioned() && !isRenderFlowThread()) {
2890         // FIXME: This is wrong if the containingBlock has a perpendicular writing mode.
2891         LayoutUnit availableHeight = containingBlockLogicalHeightForPositioned(containingBlock());
2892         return adjustContentBoxLogicalHeightForBoxSizing(valueForLength(h, availableHeight));
2893     }
2894
2895     LayoutUnit heightIncludingScrollbar = computeContentAndScrollbarLogicalHeightUsing(h, -1);
2896     if (heightIncludingScrollbar != -1)
2897         return std::max<LayoutUnit>(0, adjustContentBoxLogicalHeightForBoxSizing(heightIncludingScrollbar) - scrollbarLogicalHeight());
2898
2899     // FIXME: Check logicalTop/logicalBottom here to correctly handle vertical writing-mode.
2900     // https://bugs.webkit.org/show_bug.cgi?id=46500
2901     if (isRenderBlock() && isOutOfFlowPositioned() && style()->height().isAuto() && !(style()->top().isAuto() || style()->bottom().isAuto())) {
2902         RenderBlock* block = const_cast<RenderBlock*>(toRenderBlock(this));
2903         LogicalExtentComputedValues computedValues;
2904         block->computeLogicalHeight(block->logicalHeight(), 0, computedValues);
2905         LayoutUnit newContentHeight = computedValues.m_extent - block->borderAndPaddingLogicalHeight() - block->scrollbarLogicalHeight();
2906         return adjustContentBoxLogicalHeightForBoxSizing(newContentHeight);
2907     }
2908
2909     // FIXME: This is wrong if the containingBlock has a perpendicular writing mode.
2910     LayoutUnit availableHeight = containingBlockLogicalHeightForContent(heightType);
2911     if (heightType == ExcludeMarginBorderPadding) {
2912         // FIXME: Margin collapsing hasn't happened yet, so this incorrectly removes collapsed margins.
2913         availableHeight -= marginBefore() + marginAfter() + borderAndPaddingLogicalHeight();
2914     }
2915     return availableHeight;
2916 }
2917
2918 void RenderBox::computeAndSetBlockDirectionMargins(const RenderBlock* containingBlock)
2919 {
2920     LayoutUnit marginBefore;
2921     LayoutUnit marginAfter;
2922     computeMarginsForDirection(BlockDirection, containingBlock, containingBlockLogicalWidthForContent(), logicalHeight(), marginBefore, marginAfter,
2923         style()->marginBeforeUsing(containingBlock->style()),
2924         style()->marginAfterUsing(containingBlock->style()));
2925     // Note that in this 'positioning phase' of the layout we are using the containing block's writing mode rather than our own when calculating margins.
2926     // See http://www.w3.org/TR/2014/CR-css-writing-modes-3-20140320/#orthogonal-flows
2927     containingBlock->setMarginBeforeForChild(this, marginBefore);
2928     containingBlock->setMarginAfterForChild(this, marginAfter);
2929 }
2930
2931 LayoutUnit RenderBox::containingBlockLogicalWidthForPositioned(const RenderBoxModelObject* containingBlock, bool checkForPerpendicularWritingMode) const
2932 {
2933     if (checkForPerpendicularWritingMode && containingBlock->isHorizontalWritingMode() != isHorizontalWritingMode())
2934         return containingBlockLogicalHeightForPositioned(containingBlock, false);
2935
2936     // Use viewport as container for top-level fixed-position elements.
2937     if (style()->position() == FixedPosition && containingBlock->isRenderView()) {
2938         const RenderView* view = toRenderView(containingBlock);
2939         if (FrameView* frameView = view->frameView()) {
2940             LayoutRect viewportRect = frameView->viewportConstrainedVisibleContentRect();
2941             return containingBlock->isHorizontalWritingMode() ? viewportRect.width() : viewportRect.height();
2942         }
2943     }
2944
2945     if (containingBlock->isBox())
2946         return toRenderBox(containingBlock)->clientLogicalWidth();
2947
2948     ASSERT(containingBlock->isRenderInline() && containingBlock->isInFlowPositioned());
2949
2950     const RenderInline* flow = toRenderInline(containingBlock);
2951     InlineFlowBox* first = flow->firstLineBox();
2952     InlineFlowBox* last = flow->lastLineBox();
2953
2954     // If the containing block is empty, return a width of 0.
2955     if (!first || !last)
2956         return 0;
2957
2958     LayoutUnit fromLeft;
2959     LayoutUnit fromRight;
2960     if (containingBlock->style()->isLeftToRightDirection()) {
2961         fromLeft = first->logicalLeft() + first->borderLogicalLeft();
2962         fromRight = last->logicalLeft() + last->logicalWidth() - last->borderLogicalRight();
2963     } else {
2964         fromRight = first->logicalLeft() + first->logicalWidth() - first->borderLogicalRight();
2965         fromLeft = last->logicalLeft() + last->borderLogicalLeft();
2966     }
2967
2968     return max<LayoutUnit>(0, fromRight - fromLeft);
2969 }
2970
2971 LayoutUnit RenderBox::containingBlockLogicalHeightForPositioned(const RenderBoxModelObject* containingBlock, bool checkForPerpendicularWritingMode) const
2972 {
2973     if (checkForPerpendicularWritingMode && containingBlock->isHorizontalWritingMode() != isHorizontalWritingMode())
2974         return containingBlockLogicalWidthForPositioned(containingBlock, false);
2975
2976     // Use viewport as container for top-level fixed-position elements.
2977     if (style()->position() == FixedPosition && containingBlock->isRenderView()) {
2978         const RenderView* view = toRenderView(containingBlock);
2979         if (FrameView* frameView = view->frameView()) {
2980             LayoutRect viewportRect = frameView->viewportConstrainedVisibleContentRect();
2981             return containingBlock->isHorizontalWritingMode() ? viewportRect.height() : viewportRect.width();
2982         }
2983     }
2984
2985     if (containingBlock->isBox()) {
2986         const RenderBlock* cb = containingBlock->isRenderBlock() ?
2987             toRenderBlock(containingBlock) : containingBlock->containingBlock();
2988         return cb->clientLogicalHeight();
2989     }
2990
2991     ASSERT(containingBlock->isRenderInline() && containingBlock->isInFlowPositioned());
2992
2993     const RenderInline* flow = toRenderInline(containingBlock);
2994     InlineFlowBox* first = flow->firstLineBox();
2995     InlineFlowBox* last = flow->lastLineBox();
2996
2997     // If the containing block is empty, return a height of 0.
2998     if (!first || !last)
2999         return 0;
3000
3001     LayoutUnit heightResult;
3002     LayoutRect boundingBox = flow->linesBoundingBox();
3003     if (containingBlock->isHorizontalWritingMode())
3004         heightResult = boundingBox.height();
3005     else
3006         heightResult = boundingBox.width();
3007     heightResult -= (containingBlock->borderBefore() + containingBlock->borderAfter());
3008     return heightResult;
3009 }
3010
3011 static void computeInlineStaticDistance(Length& logicalLeft, Length& logicalRight, const RenderBox* child, const RenderBoxModelObject* containerBlock, LayoutUnit containerLogicalWidth)
3012 {
3013     if (!logicalLeft.isAuto() || !logicalRight.isAuto())
3014         return;
3015
3016     // FIXME: The static distance computation has not been patched for mixed writing modes yet.
3017     if (child->parent()->style()->direction() == LTR) {
3018         LayoutUnit staticPosition = child->layer()->staticInlinePosition() - containerBlock->borderLogicalLeft();
3019         for (RenderObject* curr = child->parent(); curr && curr != containerBlock; curr = curr->container()) {
3020             if (curr->isBox()) {
3021                 staticPosition += toRenderBox(curr)->logicalLeft();
3022                 if (toRenderBox(curr)->isRelPositioned())
3023                     staticPosition += toRenderBox(curr)->relativePositionOffset().width();
3024             } else if (curr->isInline()) {
3025                 if (curr->isRelPositioned()) {
3026                     if (!curr->style()->logicalLeft().isAuto())
3027                         staticPosition += curr->style()->logicalLeft().value();
3028                     else
3029                         staticPosition -= curr->style()->logicalRight().value();
3030                 }
3031             }
3032         }
3033         logicalLeft.setValue(Fixed, staticPosition);
3034     } else {
3035         RenderBox* enclosingBox = child->parent()->enclosingBox();
3036         LayoutUnit staticPosition = child->layer()->staticInlinePosition() + containerLogicalWidth + containerBlock->borderLogicalLeft();
3037         for (RenderObject* curr = child->parent(); curr; curr = curr->container()) {
3038             if (curr->isBox()) {
3039                 if (curr != containerBlock) {
3040                     staticPosition -= toRenderBox(curr)->logicalLeft();
3041                     if (toRenderBox(curr)->isRelPositioned())
3042                         staticPosition -= toRenderBox(curr)->relativePositionOffset().width();
3043                 }
3044                 if (curr == enclosingBox)
3045                     staticPosition -= enclosingBox->logicalWidth();
3046             } else if (curr->isInline()) {
3047                 if (curr->isRelPositioned()) {
3048                     if (!curr->style()->logicalLeft().isAuto())
3049                         staticPosition -= curr->style()->logicalLeft().value();
3050                     else
3051                         staticPosition += curr->style()->logicalRight().value();
3052                 }
3053             }
3054             if (curr == containerBlock)
3055                 break;
3056         }
3057         logicalRight.setValue(Fixed, staticPosition);
3058     }
3059 }
3060
3061 void RenderBox::computePositionedLogicalWidth(LogicalExtentComputedValues& computedValues) const
3062 {
3063     if (isReplaced()) {
3064         computePositionedLogicalWidthReplaced(computedValues);
3065         return;
3066     }
3067
3068     // QUESTIONS
3069     // FIXME 1: Should we still deal with these the cases of 'left' or 'right' having
3070     // the type 'static' in determining whether to calculate the static distance?
3071     // NOTE: 'static' is not a legal value for 'left' or 'right' as of CSS 2.1.
3072
3073     // FIXME 2: Can perhaps optimize out cases when max-width/min-width are greater
3074     // than or less than the computed width().  Be careful of box-sizing and
3075     // percentage issues.
3076
3077     // The following is based off of the W3C Working Draft from April 11, 2006 of
3078     // CSS 2.1: Section 10.3.7 "Absolutely positioned, non-replaced elements"
3079     // <http://www.w3.org/TR/CSS21/visudet.html#abs-non-replaced-width>
3080     // (block-style-comments in this function and in computePositionedLogicalWidthUsing()
3081     // correspond to text from the spec)
3082
3083
3084     // We don't use containingBlock(), since we may be positioned by an enclosing
3085     // relative positioned inline.
3086     const RenderBoxModelObject* containerBlock = toRenderBoxModelObject(container());
3087
3088     const LayoutUnit containerLogicalWidth = containingBlockLogicalWidthForPositioned(containerBlock);
3089
3090     // Use the container block's direction except when calculating the static distance
3091     // This conforms with the reference results for abspos-replaced-width-margin-000.htm
3092     // of the CSS 2.1 test suite
3093     TextDirection containerDirection = containerBlock->style()->direction();
3094
3095     bool isHorizontal = isHorizontalWritingMode();
3096     const LayoutUnit bordersPlusPadding = borderAndPaddingLogicalWidth();
3097     const Length marginLogicalLeft = isHorizontal ? style()->marginLeft() : style()->marginTop();
3098     const Length marginLogicalRight = isHorizontal ? style()->marginRight() : style()->marginBottom();
3099
3100     Length logicalLeftLength = style()->logicalLeft();
3101     Length logicalRightLength = style()->logicalRight();
3102
3103     /*---------------------------------------------------------------------------*\
3104      * For the purposes of this section and the next, the term "static position"
3105      * (of an element) refers, roughly, to the position an element would have had
3106      * in the normal flow. More precisely:
3107      *
3108      * * The static position for 'left' is the distance from the left edge of the
3109      *   containing block to the left margin edge of a hypothetical box that would
3110      *   have been the first box of the element if its 'position' property had
3111      *   been 'static' and 'float' had been 'none'. The value is negative if the
3112      *   hypothetical box is to the left of the containing block.
3113      * * The static position for 'right' is the distance from the right edge of the
3114      *   containing block to the right margin edge of the same hypothetical box as
3115      *   above. The value is positive if the hypothetical box is to the left of the
3116      *   containing block's edge.
3117      *
3118      * But rather than actually calculating the dimensions of that hypothetical box,
3119      * user agents are free to make a guess at its probable position.
3120      *
3121      * For the purposes of calculating the static position, the containing block of
3122      * fixed positioned elements is the initial containing block instead of the
3123      * viewport, and all scrollable boxes should be assumed to be scrolled to their
3124      * origin.
3125     \*---------------------------------------------------------------------------*/
3126
3127     // see FIXME 1
3128     // Calculate the static distance if needed.
3129     computeInlineStaticDistance(logicalLeftLength, logicalRightLength, this, containerBlock, containerLogicalWidth);
3130
3131     // Calculate constraint equation values for 'width' case.
3132     computePositionedLogicalWidthUsing(style()->logicalWidth(), containerBlock, containerDirection,
3133                                        containerLogicalWidth, bordersPlusPadding,
3134                                        logicalLeftLength, logicalRightLength, marginLogicalLeft, marginLogicalRight,
3135                                        computedValues);
3136
3137     // Calculate constraint equation values for 'max-width' case.
3138     if (!style()->logicalMaxWidth().isUndefined()) {
3139         LogicalExtentComputedValues maxValues;
3140
3141         computePositionedLogicalWidthUsing(style()->logicalMaxWidth(), containerBlock, containerDirection,
3142                                            containerLogicalWidth, bordersPlusPadding,
3143                                            logicalLeftLength, logicalRightLength, marginLogicalLeft, marginLogicalRight,
3144                                            maxValues);
3145
3146         if (computedValues.m_extent > maxValues.m_extent) {
3147             computedValues.m_extent = maxValues.m_extent;
3148             computedValues.m_position = maxValues.m_position;
3149             computedValues.m_margins.m_start = maxValues.m_margins.m_start;
3150             computedValues.m_margins.m_end = maxValues.m_margins.m_end;
3151         }
3152     }
3153
3154     // Calculate constraint equation values for 'min-width' case.
3155     if (!style()->logicalMinWidth().isZero() || style()->logicalMinWidth().isIntrinsic()) {
3156         LogicalExtentComputedValues minValues;
3157
3158         computePositionedLogicalWidthUsing(style()->logicalMinWidth(), containerBlock, containerDirection,
3159                                            containerLogicalWidth, bordersPlusPadding,
3160                                            logicalLeftLength, logicalRightLength, marginLogicalLeft, marginLogicalRight,
3161                                            minValues);
3162
3163         if (computedValues.m_extent < minValues.m_extent) {
3164             computedValues.m_extent = minValues.m_extent;
3165             computedValues.m_position = minValues.m_position;
3166             computedValues.m_margins.m_start = minValues.m_margins.m_start;
3167             computedValues.m_margins.m_end = minValues.m_margins.m_end;
3168         }
3169     }
3170
3171     computedValues.m_extent += bordersPlusPadding;
3172 }
3173
3174 static void computeLogicalLeftPositionedOffset(LayoutUnit& logicalLeftPos, const RenderBox* child, LayoutUnit logicalWidthValue, const RenderBoxModelObject* containerBlock, LayoutUnit containerLogicalWidth)
3175 {
3176     // Deal with differing writing modes here.  Our offset needs to be in the containing block's coordinate space. If the containing block is flipped
3177     // along this axis, then we need to flip the coordinate.  This can only happen if the containing block is both a flipped mode and perpendicular to us.
3178     if (containerBlock->isHorizontalWritingMode() != child->isHorizontalWritingMode() && containerBlock->style()->isFlippedBlocksWritingMode()) {
3179         logicalLeftPos = containerLogicalWidth - logicalWidthValue - logicalLeftPos;
3180         logicalLeftPos += (child->isHorizontalWritingMode() ? containerBlock->borderRight() : containerBlock->borderBottom());
3181     } else {
3182         logicalLeftPos += (child->isHorizontalWritingMode() ? containerBlock->borderLeft() : containerBlock->borderTop());
3183     }
3184 }
3185
3186 void RenderBox::shrinkToFitWidth(const LayoutUnit availableSpace, const LayoutUnit logicalLeftValue, const LayoutUnit bordersPlusPadding, LogicalExtentComputedValues& computedValues) const
3187 {
3188     // FIXME: would it be better to have shrink-to-fit in one step?
3189     LayoutUnit preferredWidth = maxPreferredLogicalWidth() - bordersPlusPadding;
3190     LayoutUnit preferredMinWidth = minPreferredLogicalWidth() - bordersPlusPadding;
3191     LayoutUnit availableWidth = availableSpace - logicalLeftValue;
3192     computedValues.m_extent = min(max(preferredMinWidth, availableWidth), preferredWidth);
3193 }
3194
3195 void RenderBox::computePositionedLogicalWidthUsing(Length logicalWidth, const RenderBoxModelObject* containerBlock, TextDirection containerDirection,
3196                                                    LayoutUnit containerLogicalWidth, LayoutUnit bordersPlusPadding,
3197                                                    const Length& logicalLeft, const Length& logicalRight, const Length& marginLogicalLeft,
3198                                                    const Length& marginLogicalRight, LogicalExtentComputedValues& computedValues) const
3199 {
3200     if (logicalWidth.isIntrinsic())
3201         logicalWidth = Length(computeIntrinsicLogicalWidthUsing(logicalWidth, containerLogicalWidth, bordersPlusPadding) - bordersPlusPadding, Fixed);
3202
3203     // 'left' and 'right' cannot both be 'auto' because one would of been
3204     // converted to the static position already
3205     ASSERT(!(logicalLeft.isAuto() && logicalRight.isAuto()));
3206
3207     LayoutUnit logicalLeftValue = 0;
3208
3209     const LayoutUnit containerRelativeLogicalWidth = containingBlockLogicalWidthForPositioned(containerBlock, false);
3210
3211     bool logicalWidthIsAuto = logicalWidth.isIntrinsicOrAuto();
3212     bool logicalLeftIsAuto = logicalLeft.isAuto();
3213     bool logicalRightIsAuto = logicalRight.isAuto();
3214     LayoutUnit& marginLogicalLeftValue = style()->isLeftToRightDirection() ? computedValues.m_margins.m_start : computedValues.m_margins.m_end;
3215     LayoutUnit& marginLogicalRightValue = style()->isLeftToRightDirection() ? computedValues.m_margins.m_end : computedValues.m_margins.m_start;
3216     if (!logicalLeftIsAuto && !logicalWidthIsAuto && !logicalRightIsAuto) {
3217         /*-----------------------------------------------------------------------*\
3218          * If none of the three is 'auto': If both 'margin-left' and 'margin-
3219          * right' are 'auto', solve the equation under the extra constraint that
3220          * the two margins get equal values, unless this would make them negative,
3221          * in which case when direction of the containing block is 'ltr' ('rtl'),
3222          * set 'margin-left' ('margin-right') to zero and solve for 'margin-right'
3223          * ('margin-left'). If one of 'margin-left' or 'margin-right' is 'auto',
3224          * solve the equation for that value. If the values are over-constrained,
3225          * ignore the value for 'left' (in case the 'direction' property of the
3226          * containing block is 'rtl') or 'right' (in case 'direction' is 'ltr')
3227          * and solve for that value.
3228         \*-----------------------------------------------------------------------*/
3229         // NOTE:  It is not necessary to solve for 'right' in the over constrained
3230         // case because the value is not used for any further calculations.
3231
3232         logicalLeftValue = valueForLength(logicalLeft, containerLogicalWidth);
3233         computedValues.m_extent = adjustContentBoxLogicalWidthForBoxSizing(valueForLength(logicalWidth, containerLogicalWidth));
3234
3235         const LayoutUnit availableSpace = containerLogicalWidth - (logicalLeftValue + computedValues.m_extent + valueForLength(logicalRight, containerLogicalWidth) + bordersPlusPadding);
3236
3237         // Margins are now the only unknown
3238         if (marginLogicalLeft.isAuto() && marginLogicalRight.isAuto()) {
3239             // Both margins auto, solve for equality
3240             if (availableSpace >= 0) {
3241                 marginLogicalLeftValue = availableSpace / 2; // split the difference
3242                 marginLogicalRightValue = availableSpace - marginLogicalLeftValue; // account for odd valued differences
3243             } else {
3244                 // Use the containing block's direction rather than the parent block's
3245                 // per CSS 2.1 reference test abspos-non-replaced-width-margin-000.
3246                 if (containerDirection == LTR) {
3247                     marginLogicalLeftValue = 0;
3248                     marginLogicalRightValue = availableSpace; // will be negative
3249                 } else {
3250                     marginLogicalLeftValue = availableSpace; // will be negative
3251                     marginLogicalRightValue = 0;
3252                 }
3253             }
3254         } else if (marginLogicalLeft.isAuto()) {
3255             // Solve for left margin
3256             marginLogicalRightValue = valueForLength(marginLogicalRight, containerRelativeLogicalWidth);
3257             marginLogicalLeftValue = availableSpace - marginLogicalRightValue;
3258         } else if (marginLogicalRight.isAuto()) {
3259             // Solve for right margin
3260             marginLogicalLeftValue = valueForLength(marginLogicalLeft, containerRelativeLogicalWidth);
3261             marginLogicalRightValue = availableSpace - marginLogicalLeftValue;
3262         } else {
3263             // Over-constrained, solve for left if direction is RTL
3264             marginLogicalLeftValue = valueForLength(marginLogicalLeft, containerRelativeLogicalWidth);
3265             marginLogicalRightValue = valueForLength(marginLogicalRight, containerRelativeLogicalWidth);
3266
3267             // Use the containing block's direction rather than the parent block's
3268             // per CSS 2.1 reference test abspos-non-replaced-width-margin-000.
3269             if (containerDirection == RTL)
3270                 logicalLeftValue = (availableSpace + logicalLeftValue) - marginLogicalLeftValue - marginLogicalRightValue;
3271         }
3272     } else {
3273         /*--------------------------------------------------------------------*\
3274          * Otherwise, set 'auto' values for 'margin-left' and 'margin-right'
3275          * to 0, and pick the one of the following six rules that applies.
3276          *
3277          * 1. 'left' and 'width' are 'auto' and 'right' is not 'auto', then the
3278          *    width is shrink-to-fit. Then solve for 'left'
3279          *
3280          *              OMIT RULE 2 AS IT SHOULD NEVER BE HIT
3281          * ------------------------------------------------------------------
3282          * 2. 'left' and 'right' are 'auto' and 'width' is not 'auto', then if
3283          *    the 'direction' property of the containing block is 'ltr' set
3284          *    'left' to the static position, otherwise set 'right' to the
3285          *    static position. Then solve for 'left' (if 'direction is 'rtl')
3286          *    or 'right' (if 'direction' is 'ltr').
3287          * ------------------------------------------------------------------
3288          *
3289          * 3. 'width' and 'right' are 'auto' and 'left' is not 'auto', then the
3290          *    width is shrink-to-fit . Then solve for 'right'
3291          * 4. 'left' is 'auto', 'width' and 'right' are not 'auto', then solve
3292          *    for 'left'
3293          * 5. 'width' is 'auto', 'left' and 'right' are not 'auto', then solve
3294          *    for 'width'
3295          * 6. 'right' is 'auto', 'left' and 'width' are not 'auto', then solve
3296          *    for 'right'
3297          *
3298          * Calculation of the shrink-to-fit width is similar to calculating the
3299          * width of a table cell using the automatic table layout algorithm.
3300          * Roughly: calculate the preferred width by formatting the content
3301          * without breaking lines other than where explicit line breaks occur,
3302          * and also calculate the preferred minimum width, e.g., by trying all
3303          * possible line breaks. CSS 2.1 does not define the exact algorithm.
3304          * Thirdly, calculate the available width: this is found by solving
3305          * for 'width' after setting 'left' (in case 1) or 'right' (in case 3)
3306          * to 0.
3307          *
3308          * Then the shrink-to-fit width is:
3309          * min(max(preferred minimum width, available width), preferred width).
3310         \*--------------------------------------------------------------------*/
3311         // NOTE: For rules 3 and 6 it is not necessary to solve for 'right'
3312         // because the value is not used for any further calculations.
3313
3314         // Calculate margins, 'auto' margins are ignored.
3315         marginLogicalLeftValue = minimumValueForLength(marginLogicalLeft, containerRelativeLogicalWidth);
3316         marginLogicalRightValue = minimumValueForLength(marginLogicalRight, containerRelativeLogicalWidth);
3317
3318         const LayoutUnit availableSpace = containerLogicalWidth - (marginLogicalLeftValue + marginLogicalRightValue + bordersPlusPadding);
3319
3320         // FIXME: Is there a faster way to find the correct case?
3321         // Use rule/case that applies.
3322         if (logicalLeftIsAuto && logicalWidthIsAuto && !logicalRightIsAuto) {
3323             // RULE 1: (use shrink-to-fit for width, and solve of left)
3324             LayoutUnit logicalRightValue = valueForLength(logicalRight, containerLogicalWidth);
3325
3326             // FIXME: would it be better to have shrink-to-fit in one step?
3327             LayoutUnit preferredWidth = maxPreferredLogicalWidth() - bordersPlusPadding;
3328             LayoutUnit preferredMinWidth = minPreferredLogicalWidth() - bordersPlusPadding;
3329             LayoutUnit availableWidth = availableSpace - logicalRightValue;
3330             computedValues.m_extent = min(max(preferredMinWidth, availableWidth), preferredWidth);
3331             logicalLeftValue = availableSpace - (computedValues.m_extent + logicalRightValue);
3332         } else if (!logicalLeftIsAuto && logicalWidthIsAuto && logicalRightIsAuto) {
3333             // RULE 3: (use shrink-to-fit for width, and no need solve of right)
3334             logicalLeftValue = valueForLength(logicalLeft, containerLogicalWidth);
3335
3336             shrinkToFitWidth(availableSpace, logicalLeftValue, bordersPlusPadding, computedValues);
3337         } else if (logicalLeftIsAuto && !logicalWidthIsAuto && !logicalRightIsAuto) {
3338             // RULE 4: (solve for left)
3339             computedValues.m_extent = adjustContentBoxLogicalWidthForBoxSizing(valueForLength(logicalWidth, containerLogicalWidth));
3340             logicalLeftValue = availableSpace - (computedValues.m_extent + valueForLength(logicalRight, containerLogicalWidth));
3341         } else if (!logicalLeftIsAuto && logicalWidthIsAuto && !logicalRightIsAuto) {
3342             // RULE 5: (solve for width)
3343             logicalLeftValue = valueForLength(logicalLeft, containerLogicalWidth);
3344             if (autoWidthShouldFitContent())
3345                 shrinkToFitWidth(availableSpace, logicalLeftValue, bordersPlusPadding, computedValues);
3346             else
3347                 computedValues.m_extent = availableSpace - (logicalLeftValue + valueForLength(logicalRight, containerLogicalWidth));
3348         } else if (!logicalLeftIsAuto && !logicalWidthIsAuto && logicalRightIsAuto) {
3349             // RULE 6: (no need solve for right)
3350             logicalLeftValue = valueForLength(logicalLeft, containerLogicalWidth);
3351             computedValues.m_extent = adjustContentBoxLogicalWidthForBoxSizing(valueForLength(logicalWidth, containerLogicalWidth));
3352         }
3353     }
3354
3355     // Use computed values to calculate the horizontal position.
3356
3357     // FIXME: This hack is needed to calculate the  logical left position for a 'rtl' relatively
3358     // positioned, inline because right now, it is using the logical left position
3359     // of the first line box when really it should use the last line box.  When
3360     // this is fixed elsewhere, this block should be removed.
3361     if (containerBlock->isRenderInline() && !containerBlock->style()->isLeftToRightDirection()) {
3362         const RenderInline* flow = toRenderInline(containerBlock);
3363         InlineFlowBox* firstLine = flow->firstLineBox();
3364         InlineFlowBox* lastLine = flow->lastLineBox();
3365         if (firstLine && lastLine && firstLine != lastLine) {
3366             computedValues.m_position = logicalLeftValue + marginLogicalLeftValue + lastLine->borderLogicalLeft() + (lastLine->logicalLeft() - firstLine->logicalLeft());
3367             return;
3368         }
3369     }
3370
3371     if (containerBlock->isBox() && toRenderBox(containerBlock)->scrollsOverflowY() && containerBlock->style()->shouldPlaceBlockDirectionScrollbarOnLogicalLeft()) {
3372         logicalLeftValue = logicalLeftValue + toRenderBox(containerBlock)->verticalScrollbarWidth();
3373     }
3374
3375     computedValues.m_position = logicalLeftValue + marginLogicalLeftValue;
3376     computeLogicalLeftPositionedOffset(computedValues.m_position, this, computedValues.m_extent, containerBlock, containerLogicalWidth);
3377 }
3378
3379 static void computeBlockStaticDistance(Length& logicalTop, Length& logicalBottom, const RenderBox* child, const RenderBoxModelObject* containerBlock)
3380 {
3381     if (!logicalTop.isAuto() || !logicalBottom.isAuto())
3382         return;
3383
3384     // FIXME: The static distance computation has not been patched for mixed writing modes.
3385     LayoutUnit staticLogicalTop = child->layer()->staticBlockPosition() - containerBlock->borderBefore();
3386     for (RenderObject* curr = child->parent(); curr && curr != containerBlock; curr = curr->container()) {
3387         if (curr->isBox() && !curr->isTableRow())
3388             staticLogicalTop += toRenderBox(curr)->logicalTop();
3389     }
3390     logicalTop.setValue(Fixed, staticLogicalTop);
3391 }
3392
3393 void RenderBox::computePositionedLogicalHeight(LogicalExtentComputedValues& computedValues) const
3394 {
3395     if (isReplaced()) {
3396         computePositionedLogicalHeightReplaced(computedValues);
3397         return;
3398     }
3399
3400     // The following is based off of the W3C Working Draft from April 11, 2006 of
3401     // CSS 2.1: Section 10.6.4 "Absolutely positioned, non-replaced elements"
3402     // <http://www.w3.org/TR/2005/WD-CSS21-20050613/visudet.html#abs-non-replaced-height>
3403     // (block-style-comments in this function and in computePositionedLogicalHeightUsing()
3404     // correspond to text from the spec)
3405
3406
3407     // We don't use containingBlock(), since we may be positioned by an enclosing relpositioned inline.
3408     const RenderBoxModelObject* containerBlock = toRenderBoxModelObject(container());
3409
3410     const LayoutUnit containerLogicalHeight = containingBlockLogicalHeightForPositioned(containerBlock);
3411
3412     RenderStyle* styleToUse = style();
3413     const LayoutUnit bordersPlusPadding = borderAndPaddingLogicalHeight();
3414     const Length marginBefore = styleToUse->marginBefore();
3415     const Length marginAfter = styleToUse->marginAfter();
3416     Length logicalTopLength = styleToUse->logicalTop();
3417     Length logicalBottomLength = styleToUse->logicalBottom();
3418
3419     /*---------------------------------------------------------------------------*\
3420      * For the purposes of this section and the next, the term "static position"
3421      * (of an element) refers, roughly, to the position an element would have had
3422      * in the normal flow. More precisely, the static position for 'top' is the
3423      * distance from the top edge of the containing block to the top margin edge
3424      * of a hypothetical box that would have been the first box of the element if
3425      * its 'position' property had been 'static' and 'float' had been 'none'. The
3426      * value is negative if the hypothetical box is above the containing block.
3427      *
3428      * But rather than actually calculating the dimensions of that hypothetical
3429      * box, user agents are free to make a guess at its probable position.
3430      *
3431      * For the purposes of calculating the static position, the containing block
3432      * of fixed positioned elements is the initial containing block instead of
3433      * the viewport.
3434     \*---------------------------------------------------------------------------*/
3435
3436     // see FIXME 1
3437     // Calculate the static distance if needed.
3438     computeBlockStaticDistance(logicalTopLength, logicalBottomLength, this, containerBlock);
3439
3440     // Calculate constraint equation values for 'height' case.
3441     LayoutUnit logicalHeight = computedValues.m_extent;
3442     computePositionedLogicalHeightUsing(styleToUse->logicalHeight(), containerBlock, containerLogicalHeight, bordersPlusPadding, logicalHeight,
3443                                         logicalTopLength, logicalBottomLength, marginBefore, marginAfter,
3444                                         computedValues);
3445
3446     // Avoid doing any work in the common case (where the values of min-height and max-height are their defaults).
3447     // see FIXME 2
3448
3449     // Calculate constraint equation values for 'max-height' case.
3450     if (!styleToUse->logicalMaxHeight().isUndefined()) {
3451         LogicalExtentComputedValues maxValues;
3452
3453         computePositionedLogicalHeightUsing(styleToUse->logicalMaxHeight(), containerBlock, containerLogicalHeight, bordersPlusPadding, logicalHeight,
3454                                             logicalTopLength, logicalBottomLength, marginBefore, marginAfter,
3455                                             maxValues);
3456
3457         if (computedValues.m_extent > maxValues.m_extent) {
3458             computedValues.m_extent = maxValues.m_extent;
3459             computedValues.m_position = maxValues.m_position;
3460             computedValues.m_margins.m_before = maxValues.m_margins.m_before;
3461             computedValues.m_margins.m_after = maxValues.m_margins.m_after;
3462         }
3463     }
3464
3465     // Calculate constraint equation values for 'min-height' case.
3466     if (!styleToUse->logicalMinHeight().isZero() || styleToUse->logicalMinHeight().isIntrinsic()) {
3467         LogicalExtentComputedValues minValues;
3468
3469         computePositionedLogicalHeightUsing(styleToUse->logicalMinHeight(), containerBlock, containerLogicalHeight, bordersPlusPadding, logicalHeight,
3470                                             logicalTopLength, logicalBottomLength, marginBefore, marginAfter,
3471                                             minValues);
3472
3473         if (computedValues.m_extent < minValues.m_extent) {
3474             computedValues.m_extent = minValues.m_extent;
3475             computedValues.m_position = minValues.m_position;
3476             computedValues.m_margins.m_before = minValues.m_margins.m_before;
3477             computedValues.m_margins.m_after = minValues.m_margins.m_after;
3478         }
3479     }
3480
3481     // Set final height value.
3482     computedValues.m_extent += bordersPlusPadding;
3483 }
3484
3485 static void computeLogicalTopPositionedOffset(LayoutUnit& logicalTopPos, const RenderBox* child, LayoutUnit logicalHeightValue, const RenderBoxModelObject* containerBlock, LayoutUnit containerLogicalHeight)
3486 {
3487     // Deal with differing writing modes here.  Our offset needs to be in the containing block's coordinate space. If the containing block is flipped
3488     // along this axis, then we need to flip the coordinate.  This can only happen if the containing block is both a flipped mode and perpendicular to us.
3489     if ((child->style()->isFlippedBlocksWritingMode() && child->isHorizontalWritingMode() != containerBlock->isHorizontalWritingMode())
3490         || (child->style()->isFlippedBlocksWritingMode() != containerBlock->style()->isFlippedBlocksWritingMode() && child->isHorizontalWritingMode() == containerBlock->isHorizontalWritingMode()))
3491         logicalTopPos = containerLogicalHeight - logicalHeightValue - logicalTopPos;
3492
3493     // Our offset is from the logical bottom edge in a flipped environment, e.g., right for vertical-rl and bottom for horizontal-bt.
3494     if (containerBlock->style()->isFlippedBlocksWritingMode() && child->isHorizontalWritingMode() == containerBlock->isHorizontalWritingMode()) {
3495         if (child->isHorizontalWritingMode())
3496             logicalTopPos += containerBlock->borderBottom();
3497         else
3498             logicalTopPos += containerBlock->borderRight();
3499     } else {
3500         if (child->isHorizontalWritingMode())
3501             logicalTopPos += containerBlock->borderTop();
3502         else
3503             logicalTopPos += containerBlock->borderLeft();
3504     }
3505 }
3506
3507 void RenderBox::computePositionedLogicalHeightUsing(Length logicalHeightLength, const RenderBoxModelObject* containerBlock,
3508                                                     LayoutUnit containerLogicalHeight, LayoutUnit bordersPlusPadding, LayoutUnit logicalHeight,
3509                                                     const Length& logicalTop, const Length& logicalBottom, const Length& marginBefore,
3510                                                     const Length& marginAfter, LogicalExtentComputedValues& computedValues) const
3511 {
3512     // 'top' and 'bottom' cannot both be 'auto' because 'top would of been
3513     // converted to the static position in computePositionedLogicalHeight()
3514     ASSERT(!(logicalTop.isAuto() && logicalBottom.isAuto()));
3515
3516     LayoutUnit logicalHeightValue;
3517     LayoutUnit contentLogicalHeight = logicalHeight - bordersPlusPadding;
3518
3519     const LayoutUnit containerRelativeLogicalWidth = containingBlockLogicalWidthForPositioned(containerBlock, false);
3520
3521     LayoutUnit logicalTopValue = 0;
3522
3523     bool logicalHeightIsAuto = logicalHeightLength.isAuto();
3524     bool logicalTopIsAuto = logicalTop.isAuto();
3525     bool logicalBottomIsAuto = logicalBottom.isAuto();
3526
3527     LayoutUnit resolvedLogicalHeight;
3528     // Height is never unsolved for tables.
3529     if (isTable()) {
3530         resolvedLogicalHeight = contentLogicalHeight;
3531         logicalHeightIsAuto = false;
3532     } else {
3533         if (logicalHeightLength.isIntrinsic())
3534             resolvedLogicalHeight = computeIntrinsicLogicalContentHeightUsing(logicalHeightLength, contentLogicalHeight, bordersPlusPadding);
3535         else
3536             resolvedLogicalHeight = adjustContentBoxLogicalHeightForBoxSizing(valueForLength(logicalHeightLength, containerLogicalHeight));
3537     }
3538
3539     if (!logicalTopIsAuto && !logicalHeightIsAuto && !logicalBottomIsAuto) {
3540         /*-----------------------------------------------------------------------*\
3541          * If none of the three are 'auto': If both 'margin-top' and 'margin-
3542          * bottom' are 'auto', solve the equation under the extra constraint that
3543          * the two margins get equal values. If one of 'margin-top' or 'margin-
3544          * bottom' is 'auto', solve the equation for that value. If the values
3545          * are over-constrained, ignore the value for 'bottom' and solve for that
3546          * value.
3547         \*-----------------------------------------------------------------------*/
3548         // NOTE:  It is not necessary to solve for 'bottom' in the over constrained
3549         // case because the value is not used for any further calculations.
3550
3551         logicalHeightValue = resolvedLogicalHeight;
3552         logicalTopValue = valueForLength(logicalTop, containerLogicalHeight);
3553
3554         const LayoutUnit availableSpace = containerLogicalHeight - (logicalTopValue + logicalHeightValue + valueForLength(logicalBottom, containerLogicalHeight) + bordersPlusPadding);
3555
3556         // Margins are now the only unknown
3557         if (marginBefore.isAuto() && marginAfter.isAuto()) {
3558             // Both margins auto, solve for equality
3559             // NOTE: This may result in negative values.
3560             computedValues.m_margins.m_before = availableSpace / 2; // split the difference
3561             computedValues.m_margins.m_after = availableSpace - computedValues.m_margins.m_before; // account for odd valued differences
3562         } else if (marginBefore.isAuto()) {
3563             // Solve for top margin
3564             computedValues.m_margins.m_after = valueForLength(marginAfter, containerRelativeLogicalWidth);
3565             computedValues.m_margins.m_before = availableSpace - computedValues.m_margins.m_after;
3566         } else if (marginAfter.isAuto()) {
3567             // Solve for bottom margin
3568             computedValues.m_margins.m_before = valueForLength(marginBefore, containerRelativeLogicalWidth);
3569             computedValues.m_margins.m_after = availableSpace - computedValues.m_margins.m_before;
3570         } else {
3571             // Over-constrained, (no need solve for bottom)
3572             computedValues.m_margins.m_before = valueForLength(marginBefore, containerRelativeLogicalWidth);
3573             computedValues.m_margins.m_after = valueForLength(marginAfter, containerRelativeLogicalWidth);
3574         }
3575     } else {
3576         /*--------------------------------------------------------------------*\
3577          * Otherwise, set 'auto' values for 'margin-top' and 'margin-bottom'
3578          * to 0, and pick the one of the following six rules that applies.
3579          *
3580          * 1. 'top' and 'height' are 'auto' and 'bottom' is not 'auto', then
3581          *    the height is based on the content, and solve for 'top'.
3582          *
3583          *              OMIT RULE 2 AS IT SHOULD NEVER BE HIT
3584          * ------------------------------------------------------------------
3585          * 2. 'top' and 'bottom' are 'auto' and 'height' is not 'auto', then
3586          *    set 'top' to the static position, and solve for 'bottom'.
3587          * ------------------------------------------------------------------
3588          *
3589          * 3. 'height' and 'bottom' are 'auto' and 'top' is not 'auto', then
3590          *    the height is based on the content, and solve for 'bottom'.
3591          * 4. 'top' is 'auto', 'height' and 'bottom' are not 'auto', and
3592          *    solve for 'top'.
3593          * 5. 'height' is 'auto', 'top' and 'bottom' are not 'auto', and
3594          *    solve for 'height'.
3595          * 6. 'bottom' is 'auto', 'top' and 'height' are not 'auto', and
3596          *    solve for 'bottom'.
3597         \*--------------------------------------------------------------------*/
3598         // NOTE: For rules 3 and 6 it is not necessary to solve for 'bottom'
3599         // because the value is not used for any further calculations.
3600
3601         // Calculate margins, 'auto' margins are ignored.
3602         computedValues.m_margins.m_before = minimumValueForLength(marginBefore, containerRelativeLogicalWidth);
3603         computedValues.m_margins.m_after = minimumValueForLength(marginAfter, containerRelativeLogicalWidth);
3604
3605         const LayoutUnit availableSpace = containerLogicalHeight - (computedValues.m_margins.m_before + computedValues.m_margins.m_after + bordersPlusPadding);
3606
3607         // Use rule/case that applies.
3608         if (logicalTopIsAuto && logicalHeightIsAuto && !logicalBottomIsAuto) {
3609             // RULE 1: (height is content based, solve of top)
3610             logicalHeightValue = contentLogicalHeight;
3611             logicalTopValue = availableSpace - (logicalHeightValue + valueForLength(logicalBottom, containerLogicalHeight));
3612         } else if (!logicalTopIsAuto && logicalHeightIsAuto && logicalBottomIsAuto) {
3613             // RULE 3: (height is content based, no need solve of bottom)
3614             logicalTopValue = valueForLength(logicalTop, containerLogicalHeight);
3615             logicalHeightValue = contentLogicalHeight;
3616         } else if (logicalTopIsAuto && !logicalHeightIsAuto && !logicalBottomIsAuto) {
3617             // RULE 4: (solve of top)
3618             logicalHeightValue = resolvedLogicalHeight;
3619             logicalTopValue = availableSpace - (logicalHeightValue + valueForLength(logicalBottom, containerLogicalHeight));
3620         } else if (!logicalTopIsAuto && logicalHeightIsAuto && !logicalBottomIsAuto) {
3621             // RULE 5: (solve of height)
3622             logicalTopValue = valueForLength(logicalTop, containerLogicalHeight);
3623             logicalHeightValue = max<LayoutUnit>(0, availableSpace - (logicalTopValue + valueForLength(logicalBottom, containerLogicalHeight)));
3624         } else if (!logicalTopIsAuto && !logicalHeightIsAuto && logicalBottomIsAuto) {
3625             // RULE 6: (no need solve of bottom)
3626             logicalHeightValue = resolvedLogicalHeight;
3627             logicalTopValue = valueForLength(logicalTop, containerLogicalHeight);
3628         }
3629     }
3630     computedValues.m_extent = logicalHeightValue;
3631
3632     // Use computed values to calculate the vertical position.
3633     computedValues.m_position = logicalTopValue + computedValues.m_margins.m_before;
3634     computeLogicalTopPositionedOffset(computedValues.m_position, this, logicalHeightValue, containerBlock, containerLogicalHeight);
3635 }
3636
3637 void RenderBox::computePositionedLogicalWidthReplaced(LogicalExtentComputedValues& computedValues) const
3638 {
3639     // The following is based off of the W3C Working Draft from April 11, 2006 of
3640     // CSS 2.1: Section 10.3.8 "Absolutely positioned, replaced elements"
3641     // <http://www.w3.org/TR/2005/WD-CSS21-20050613/visudet.html#abs-replaced-width>
3642     // (block-style-comments in this function correspond to text from the spec and
3643     // the numbers correspond to numbers in spec)
3644
3645     // We don't use containingBlock(), since we may be positioned by an enclosing
3646     // relative positioned inline.
3647     const RenderBoxModelObject* containerBlock = toRenderBoxModelObject(container());
3648
3649     const LayoutUnit containerLogicalWidth = containingBlockLogicalWidthForPositioned(containerBlock);
3650     const LayoutUnit containerRelativeLogicalWidth = containingBlockLogicalWidthForPositioned(containerBlock, false);
3651
3652     // To match WinIE, in quirks mode use the parent's 'direction' property
3653     // instead of the the container block's.
3654     TextDirection containerDirection = containerBlock->style()->direction();
3655
3656     // Variables to solve.
3657     bool isHorizontal = isHorizontalWritingMode();
3658     Length logicalLeft = style()->logicalLeft();
3659     Length logicalRight = style()->logicalRight();
3660     Length marginLogicalLeft = isHorizontal ? style()->marginLeft() : style()->marginTop();
3661     Length marginLogicalRight = isHorizontal ? style()->marginRight() : style()->marginBottom();
3662     LayoutUnit& marginLogicalLeftAlias = style()->isLeftToRightDirection() ? computedValues.m_margins.m_start : computedValues.m_margins.m_end;
3663     LayoutUnit& marginLogicalRightAlias = style()->isLeftToRightDirection() ? computedValues.m_margins.m_end : computedValues.m_margins.m_start;
3664
3665     /*-----------------------------------------------------------------------*\
3666      * 1. The used value of 'width' is determined as for inline replaced
3667      *    elements.
3668     \*-----------------------------------------------------------------------*/
3669     // NOTE: This value of width is FINAL in that the min/max width calculations
3670     // are dealt with in computeReplacedWidth().  This means that the steps to produce
3671     // correct max/min in the non-replaced version, are not necessary.
3672     computedValues.m_extent = computeReplacedLogicalWidth() + borderAndPaddingLogicalWidth();
3673
3674     const LayoutUnit availableSpace = containerLogicalWidth - computedValues.m_extent;
3675
3676     /*-----------------------------------------------------------------------*\
3677      * 2. If both 'left' and 'right' have the value 'auto', then if 'direction'
3678      *    of the containing block is 'ltr', set 'left' to the static position;
3679      *    else if 'direction' is 'rtl', set 'right' to the static position.
3680     \*-----------------------------------------------------------------------*/
3681     // see FIXME 1
3682     computeInlineStaticDistance(logicalLeft, logicalRight, this, containerBlock, containerLogicalWidth);
3683
3684     /*-----------------------------------------------------------------------*\
3685      * 3. If 'left' or 'right' are 'auto', replace any 'auto' on 'margin-left'
3686      *    or 'margin-right' with '0'.
3687     \*-----------------------------------------------------------------------*/
3688     if (logicalLeft.isAuto() || logicalRight.isAuto()) {
3689         if (marginLogicalLeft.isAuto())
3690             marginLogicalLeft.setValue(Fixed, 0);
3691         if (marginLogicalRight.isAuto())
3692             marginLogicalRight.setValue(Fixed, 0);
3693     }
3694
3695     /*-----------------------------------------------------------------------*\
3696      * 4. If at this point both 'margin-left' and 'margin-right' are still
3697      *    'auto', solve the equation under the extra constraint that the two
3698      *    margins must get equal values, unless this would make them negative,
3699      *    in which case when the direction of the containing block is 'ltr'
3700      *    ('rtl'), set 'margin-left' ('margin-right') to zero and solve for
3701      *    'margin-right' ('margin-left').
3702     \*-----------------------------------------------------------------------*/
3703     LayoutUnit logicalLeftValue = 0;
3704     LayoutUnit logicalRightValue = 0;
3705
3706     if (marginLogicalLeft.isAuto() && marginLogicalRight.isAuto()) {
3707         // 'left' and 'right' cannot be 'auto' due to step 3
3708         ASSERT(!(logicalLeft.isAuto() && logicalRight.isAuto()));
3709
3710         logicalLeftValue = valueForLength(logicalLeft, containerLogicalWidth);
3711         logicalRightValue = valueForLength(logicalRight, containerLogicalWidth);
3712
3713         LayoutUnit difference = availableSpace - (logicalLeftValue + logicalRightValue);
3714         if (difference > 0) {
3715             marginLogicalLeftAlias = difference / 2; // split the difference
3716             marginLogicalRightAlias = difference - marginLogicalLeftAlias; // account for odd valued differences
3717         } else {
3718             // Use the containing block's direction rather than the parent block's
3719             // per CSS 2.1 reference test abspos-replaced-width-margin-000.
3720             if (containerDirection == LTR) {
3721                 marginLogicalLeftAlias = 0;
3722                 marginLogicalRightAlias = difference; // will be negative
3723             } else {
3724                 marginLogicalLeftAlias = difference; // will be negative
3725                 marginLogicalRightAlias = 0;
3726             }
3727         }
3728
3729     /*-----------------------------------------------------------------------*\
3730      * 5. If at this point there is an 'auto' left, solve the equation for
3731      *    that value.
3732     \*-----------------------------------------------------------------------*/
3733     } else if (logicalLeft.isAuto()) {
3734         marginLogicalLeftAlias = valueForLength(marginLogicalLeft, containerRelativeLogicalWidth);
3735         marginLogicalRightAlias = valueForLength(marginLogicalRight, containerRelativeLogicalWidth);
3736         logicalRightValue = valueForLength(logicalRight, containerLogicalWidth);
3737
3738         // Solve for 'left'
3739         logicalLeftValue = availableSpace - (logicalRightValue + marginLogicalLeftAlias + marginLogicalRightAlias);
3740     } else if (logicalRight.isAuto()) {
3741         marginLogicalLeftAlias = valueForLength(marginLogicalLeft, containerRelativeLogicalWidth);
3742         marginLogicalRightAlias = valueForLength(marginLogicalRight, containerRelativeLogicalWidth);
3743         logicalLeftValue = valueForLength(logicalLeft, containerLogicalWidth);
3744
3745         // Solve for 'right'
3746         logicalRightValue = availableSpace - (logicalLeftValue + marginLogicalLeftAlias + marginLogicalRightAlias);
3747     } else if (marginLogicalLeft.isAuto()) {
3748         marginLogicalRightAlias = valueForLength(marginLogicalRight, containerRelativeLogicalWidth);
3749         logicalLeftValue = valueForLength(logicalLeft, containerLogicalWidth);
3750         logicalRightValue = valueForLength(logicalRight, containerLogicalWidth);
3751
3752         // Solve for 'margin-left'
3753         marginLogicalLeftAlias = availableSpace - (logicalLeftValue + logicalRightValue + marginLogicalRightAlias);
3754     } else if (marginLogicalRight.isAuto()) {
3755         marginLogicalLeftAlias = valueForLength(marginLogicalLeft, containerRelativeLogicalWidth);
3756         logicalLeftValue = valueForLength(logicalLeft, containerLogicalWidth);
3757         logicalRightValue = valueForLength(logicalRight, containerLogicalWidth);
3758
3759         // Solve for 'margin-right'
3760         marginLogicalRightAlias = availableSpace - (logicalLeftValue + logicalRightValue + marginLogicalLeftAlias);
3761     } else {
3762         // Nothing is 'auto', just calculate the values.
3763         marginLogicalLeftAlias = valueForLength(marginLogicalLeft, containerRelativeLogicalWidth);
3764         marginLogicalRightAlias = valueForLength(marginLogicalRight, containerRelativeLogicalWidth);
3765         logicalRightValue = valueForLength(logicalRight, containerLogicalWidth);
3766         logicalLeftValue = valueForLength(logicalLeft, containerLogicalWidth);
3767         // If the containing block is right-to-left, then push the left position as far to the right as possible
3768         if (containerDirection == RTL) {
3769             int totalLogicalWidth = computedValues.m_extent + logicalLeftValue + logicalRightValue +  marginLogicalLeftAlias + marginLogicalRightAlias;
3770             logicalLeftValue = containerLogicalWidth - (totalLogicalWidth - logicalLeftValue);
3771         }
3772     }
3773
3774     /*-----------------------------------------------------------------------*\
3775      * 6. If at this point the values are over-constrained, ignore the value
3776      *    for either 'left' (in case the 'direction' property of the
3777      *    containing block is 'rtl') or 'right' (in case 'direction' is
3778      *    'ltr') and solve for that value.
3779     \*-----------------------------------------------------------------------*/
3780     // NOTE: Constraints imposed by the width of the containing block and its content have already been accounted for above.
3781
3782     // FIXME: Deal with differing writing modes here.  Our offset needs to be in the containing block's coordinate space, so that
3783     // can make the result here rather complicated to compute.
3784
3785     // Use computed values to calculate the horizontal position.
3786
3787     // FIXME: This hack is needed to calculate the logical left position for a 'rtl' relatively
3788     // positioned, inline containing block because right now, it is using the logical left position
3789     // of the first line box when really it should use the last line box.  When
3790     // this is fixed elsewhere, this block should be removed.
3791     if (containerBlock->isRenderInline() && !containerBlock->style()->isLeftToRightDirection()) {
3792         const RenderInline* flow = toRenderInline(containerBlock);
3793         InlineFlowBox* firstLine = flow->firstLineBox();
3794         InlineFlowBox* lastLine = flow->lastLineBox();
3795         if (firstLine && lastLine && firstLine != lastLine) {
3796             computedValues.m_position = logicalLeftValue + marginLogicalLeftAlias + lastLine->borderLogicalLeft() + (lastLine->logicalLeft() - firstLine->logicalLeft());
3797             return;
3798         }
3799     }
3800
3801     LayoutUnit logicalLeftPos = logicalLeftValue + marginLogicalLeftAlias;
3802     computeLogicalLeftPositionedOffset(logicalLeftPos, this, computedValues.m_extent, containerBlock, containerLogicalWidth);
3803     computedValues.m_position = logicalLeftPos;
3804 }
3805
3806 void RenderBox::computePositionedLogicalHeightReplaced(LogicalExtentComputedValues& computedValues) const
3807 {
3808     // The following is based off of the W3C Working Draft from April 11, 2006 of
3809     // CSS 2.1: Section 10.6.5 "Absolutely positioned, replaced elements"
3810     // <http://www.w3.org/TR/2005/WD-CSS21-20050613/visudet.html#abs-replaced-height>
3811     // (block-style-comments in this function correspond to text from the spec and
3812     // the numbers correspond to numbers in spec)
3813
3814     // We don't use containingBlock(), since we may be positioned by an enclosing relpositioned inline.
3815     const RenderBoxModelObject* containerBlock = toRenderBoxModelObject(container());
3816
3817     const LayoutUnit containerLogicalHeight = containingBlockLogicalHeightForPositioned(containerBlock);
3818     const LayoutUnit containerRelativeLogicalWidth = containingBlockLogicalWidthForPositioned(containerBlock, false);
3819
3820     // Variables to solve.
3821     Length marginBefore = style()->marginBefore();
3822     Length marginAfter = style()->marginAfter();
3823     LayoutUnit& marginBeforeAlias = computedValues.m_margins.m_before;
3824     LayoutUnit& marginAfterAlias = computedValues.m_margins.m_after;
3825
3826     Length logicalTop = style()->logicalTop();
3827     Length logicalBottom = style()->logicalBottom();
3828
3829     /*-----------------------------------------------------------------------*\
3830      * 1. The used value of 'height' is determined as for inline replaced
3831      *    elements.
3832     \*-----------------------------------------------------------------------*/
3833     // NOTE: This value of height is FINAL in that the min/max height calculations
3834     // are dealt with in computeReplacedHeight().  This means that the steps to produce
3835     // correct max/min in the non-replaced version, are not necessary.
3836     computedValues.m_extent = computeReplacedLogicalHeight() + borderAndPaddingLogicalHeight();
3837     const LayoutUnit availableSpace = containerLogicalHeight - computedValues.m_extent;
3838
3839     /*-----------------------------------------------------------------------*\
3840      * 2. If both 'top' and 'bottom' have the value 'auto', replace 'top'
3841      *    with the element's static position.
3842     \*-----------------------------------------------------------------------*/
3843     // see FIXME 1
3844     computeBlockStaticDistance(logicalTop, logicalBottom, this, containerBlock);
3845
3846     /*-----------------------------------------------------------------------*\
3847      * 3. If 'bottom' is 'auto', replace any 'auto' on 'margin-top' or
3848      *    'margin-bottom' with '0'.
3849     \*-----------------------------------------------------------------------*/
3850     // FIXME: The spec. says that this step should only be taken when bottom is
3851     // auto, but if only top is auto, this makes step 4 impossible.
3852     if (logicalTop.isAuto() || logicalBottom.isAuto()) {
3853         if (marginBefore.isAuto())
3854             marginBefore.setValue(Fixed, 0);
3855         if (marginAfter.isAuto())
3856             marginAfter.setValue(Fixed, 0);
3857     }
3858
3859     /*-----------------------------------------------------------------------*\
3860      * 4. If at this point both 'margin-top' and 'margin-bottom' are still
3861      *    'auto', solve the equation under the extra constraint that the two
3862      *    margins must get equal values.
3863     \*-----------------------------------------------------------------------*/
3864     LayoutUnit logicalTopValue = 0;
3865     LayoutUnit logicalBottomValue = 0;
3866
3867     if (marginBefore.isAuto() && marginAfter.isAuto()) {
3868         // 'top' and 'bottom' cannot be 'auto' due to step 2 and 3 combined.
3869         ASSERT(!(logicalTop.isAuto() || logicalBottom.isAuto()));
3870
3871         logicalTopValue = valueForLength(logicalTop, containerLogicalHeight);
3872         logicalBottomValue = valueForLength(logicalBottom, containerLogicalHeight);
3873
3874         LayoutUnit difference = availableSpace - (logicalTopValue + logicalBottomValue);
3875         // NOTE: This may result in negative values.
3876         marginBeforeAlias =  difference / 2; // split the difference
3877         marginAfterAlias = difference - marginBeforeAlias; // account for odd valued differences
3878
3879     /*-----------------------------------------------------------------------*\
3880      * 5. If at this point there is only one 'auto' left, solve the equation
3881      *    for that value.
3882     \*-----------------------------------------------------------------------*/
3883     } else if (logicalTop.isAuto()) {
3884         marginBeforeAlias = valueForLength(marginBefore, containerRelativeLogicalWidth);
3885         marginAfterAlias = valueForLength(marginAfter, containerRelativeLogicalWidth);
3886         logicalBottomValue = valueForLength(logicalBottom, containerLogicalHeight);
3887
3888         // Solve for 'top'
3889         logicalTopValue = availableSpace - (logicalBottomValue + marginBeforeAlias + marginAfterAlias);
3890     } else if (logicalBottom.isAuto()) {
3891         marginBeforeAlias = valueForLength(marginBefore, containerRelativeLogicalWidth);
3892         marginAfterAlias = valueForLength(marginAfter, containerRelativeLogicalWidth);
3893         logicalTopValue = valueForLength(logicalTop, containerLogicalHeight);
3894
3895         // Solve for 'bottom'
3896         // NOTE: It is not necessary to solve for 'bottom' because we don't ever
3897         // use the value.
3898     } else if (marginBefore.isAuto()) {
3899         marginAfterAlias = valueForLength(marginAfter, containerRelativeLogicalWidth);
3900         logicalTopValue = valueForLength(logicalTop, containerLogicalHeight);
3901         logicalBottomValue = valueForLength(logicalBottom, containerLogicalHeight);
3902
3903         // Solve for 'margin-top'
3904         marginBeforeAlias = availableSpace - (logicalTopValue + logicalBottomValue + marginAfterAlias);
3905     } else if (marginAfter.isAuto()) {
3906         marginBeforeAlias = valueForLength(marginBefore, containerRelativeLogicalWidth);
3907         logicalTopValue = valueForLength(logicalTop, containerLogicalHeight);
3908         logicalBottomValue = valueForLength(logicalBottom, containerLogicalHeight);
3909
3910         // Solve for 'margin-bottom'
3911         marginAfterAlias = availableSpace - (logicalTopValue + logicalBottomValue + marginBeforeAlias);
3912     } else {
3913         // Nothing is 'auto', just calculate the values.
3914         marginBeforeAlias = valueForLength(marginBefore, containerRelativeLogicalWidth);
3915         marginAfterAlias = valueForLength(marginAfter, containerRelativeLogicalWidth);
3916         logicalTopValue = valueForLength(logicalTop, containerLogicalHeight);
3917         // NOTE: It is not necessary to solve for 'bottom' because we don't ever
3918         // use the value.
3919      }
3920
3921     /*-----------------------------------------------------------------------*\
3922      * 6. If at this point the values are over-constrained, ignore the value
3923      *    for 'bottom' and solve for that value.
3924     \*-----------------------------------------------------------------------*/
3925     // NOTE: It is not necessary to do this step because we don't end up using
3926     // the value of 'bottom' regardless of whether the values are over-constrained
3927     // or not.
3928
3929     // Use computed values to calculate the vertical position.
3930     LayoutUnit logicalTopPos = logicalTopValue + marginBeforeAlias;
3931     computeLogicalTopPositionedOffset(logicalTopPos, this, computedValues.m_extent, containerBlock, containerLogicalHeight);
3932     computedValues.m_position = logicalTopPos;
3933 }
3934
3935 LayoutRect RenderBox::localCaretRect(InlineBox* box, int caretOffset, LayoutUnit* extraWidthToEndOfLine)
3936 {
3937     // VisiblePositions at offsets inside containers either a) refer to the positions before/after
3938     // those containers (tables and select elements) or b) refer to the position inside an empty block.
3939     // They never refer to children.
3940     // FIXME: Paint the carets inside empty blocks differently than the carets before/after elements.
3941
3942     LayoutRect rect(location(), LayoutSize(caretWidth, height()));
3943     bool ltr = box ? box->isLeftToRightDirection() : style()->isLeftToRightDirection();
3944
3945     if ((!caretOffset) ^ ltr)
3946         rect.move(LayoutSize(width() - caretWidth, 0));
3947
3948     if (box) {
3949         RootInlineBox& rootBox = box->root();
3950         LayoutUnit top = rootBox.lineTop();
3951         rect.setY(top);
3952         rect.setHeight(rootBox.lineBottom() - top);
3953     }
3954
3955     // If height of box is smaller than font height, use the latter one,
3956     // otherwise the caret might become invisible.
3957     //
3958     // Also, if the box is not a replaced element, always use the font height.
3959     // This prevents the "big caret" bug described in:
3960     // <rdar://problem/3777804> Deleting all content in a document can result in giant tall-as-window insertion point
3961     //
3962     // FIXME: ignoring :first-line, missing good reason to take care of
3963     LayoutUnit fontHeight = style()->fontMetrics().height();
3964     if (fontHeight > rect.height() || (!isReplaced() && !isTable()))
3965         rect.setHeight(fontHeight);
3966
3967     if (extraWidthToEndOfLine)
3968         *extraWidthToEndOfLine = x() + width() - rect.maxX();
3969
3970     // Move to local coords
3971     rect.moveBy(-location());
3972
3973     // FIXME: Border/padding should be added for all elements but this workaround
3974     // is needed because we use offsets inside an "atomic" element to represent
3975     // positions before and after the element in deprecated editing offsets.
3976     if (node() && !(editingIgnoresContent(node()) || isRenderedTable(node()))) {
3977         rect.setX(rect.x() + borderLeft() + paddingLeft());
3978         rect.setY(rect.y() + paddingTop() + borderTop());
3979     }
3980
3981     if (!isHorizontalWritingMode())
3982         return rect.transposedRect();
3983
3984     return rect;
3985 }
3986
3987 PositionWithAffinity RenderBox::positionForPoint(const LayoutPoint& point)
3988 {
3989     // no children...return this render object's element, if there is one, and offset 0
3990     RenderObject* firstChild = slowFirstChild();
3991     if (!firstChild)
3992         return createPositionWithAffinity(nonPseudoNode() ? firstPositionInOrBeforeNode(nonPseudoNode()) : Position());
3993
3994     if (isTable() && nonPseudoNode()) {
3995         LayoutUnit right = contentWidth() + borderAndPaddingWidth();
3996         LayoutUnit bottom = contentHeight() + borderAndPaddingHeight();
3997
3998         if (point.x() < 0 || point.x() > right || point.y() < 0 || point.y() > bottom) {
3999             if (point.x() <= right / 2)
4000                 return createPositionWithAffinity(firstPositionInOrBeforeNode(nonPseudoNode()));
4001             return createPositionWithAffinity(lastPositionInOrAfterNode(nonPseudoNode()));
4002         }
4003     }
4004
4005     // Pass off to the closest child.
4006     LayoutUnit minDist = LayoutUnit::max();
4007     RenderBox* closestRenderer = 0;
4008     LayoutPoint adjustedPoint = point;
4009     if (isTableRow())
4010         adjustedPoint.moveBy(location());
4011
4012     for (RenderObject* renderObject = firstChild; renderObject; renderObject = renderObject->nextSibling()) {
4013         if ((!renderObject->slowFirstChild() && !renderObject->isInline() && !renderObject->isRenderBlockFlow() )
4014             || renderObject->style()->visibility() != VISIBLE)
4015             continue;
4016
4017         if (!renderObject->isBox())
4018             continue;
4019
4020         RenderBox* renderer = toRenderBox(renderObject);
4021
4022         LayoutUnit top = renderer->borderTop() + renderer->paddingTop() + (isTableRow() ? LayoutUnit() : renderer->y());
4023         LayoutUnit bottom = top + renderer->contentHeight();
4024         LayoutUnit left = renderer->borderLeft() + renderer->paddingLeft() + (isTableRow() ? LayoutUnit() : renderer->x());
4025         LayoutUnit right = left + renderer->contentWidth();
4026
4027         if (point.x() <= right && point.x() >= left && point.y() <= top && point.y() >= bottom) {
4028             if (renderer->isTableRow())
4029                 return renderer->positionForPoint(point + adjustedPoint - renderer->locationOffset());
4030             return renderer->positionForPoint(point - renderer->locationOffset());
4031         }
4032
4033         // Find the distance from (x, y) to the box.  Split the space around the box into 8 pieces
4034         // and use a different compare depending on which piece (x, y) is in.
4035         LayoutPoint cmp;
4036         if (point.x() > right) {
4037             if (point.y() < top)
4038                 cmp = LayoutPoint(right, top);
4039             else if (point.y() > bottom)
4040                 cmp = LayoutPoint(right, bottom);
4041             else
4042                 cmp = LayoutPoint(right, point.y());
4043         } else if (point.x() < left) {
4044             if (point.y() < top)
4045                 cmp = LayoutPoint(left, top);
4046             else if (point.y() > bottom)
4047                 cmp = LayoutPoint(left, bottom);
4048             else
4049                 cmp = LayoutPoint(left, point.y());
4050         } else {
4051             if (point.y() < top)
4052                 cmp = LayoutPoint(point.x(), top);
4053             else
4054                 cmp = LayoutPoint(point.x(), bottom);
4055         }
4056
4057         LayoutSize difference = cmp - point;
4058
4059         LayoutUnit dist = difference.width() * difference.width() + difference.height() * difference.height();
4060         if (dist < minDist) {
4061             closestRenderer = renderer;
4062             minDist = dist;
4063         }
4064     }
4065
4066     if (closestRenderer)
4067         return closestRenderer->positionForPoint(adjustedPoint - closestRenderer->locationOffset());
4068     return createPositionWithAffinity(firstPositionInOrBeforeNode(nonPseudoNode()));
4069 }
4070
4071 bool RenderBox::shrinkToAvoidFloats() const
4072 {
4073     // Floating objects don't shrink.  Objects that don't avoid floats don't shrink.  Marquees don't shrink.
4074     if ((isInline() && !isMarquee()) || !avoidsFloats() || isFloating())
4075         return false;
4076
4077     // Only auto width objects can possibly shrink to avoid floats.
4078     return style()->width().isAuto();
4079 }
4080
4081 bool RenderBox::avoidsFloats() const
4082 {
4083     // CSS2.1: "The border box of a table, a block-level replaced element, or an element in the normal flow that establishes a new block formatting
4084     // context .. must not overlap the margin box of any floats in the same block formatting context."
4085     // FIXME: The inclusion of horizontal rule and legend elements here isn't covered by any spec.
4086     return isReplaced() || isHR() || isLegend() || isTable() || (!isFloatingOrOutOfFlowPositioned() && createsBlockFormattingContext());
4087 }
4088
4089 bool RenderBox::createsBlockFormattingContext() const
4090 {
4091     return isInlineBlockOrInlineTable() || isFloatingOrOutOfFlowPositioned() || hasOverflowClip() || isFlexItemIncludingDeprecated()
4092         || style()->specifiesColumns() || isRenderFlowThread() || isTableCell() || isTableCaption() || isFieldset() || isWritingModeRoot() || isDocumentElement() || style()->columnSpan();
4093 }
4094
4095 void RenderBox::markForPaginationRelayoutIfNeeded(SubtreeLayoutScope& layoutScope)
4096 {
4097     ASSERT(!needsLayout());
4098     // If fragmentation height has changed, we need to lay out. No need to enter the renderer if it
4099     // is childless, though.
4100     if (view()->layoutState()->pageLogicalHeightChanged() && slowFirstChild())
4101         layoutScope.setChildNeedsLayout(this);
4102 }
4103
4104 void RenderBox::addVisualEffectOverflow()
4105 {
4106     if (!style()->boxShadow() && !style()->hasBorderImageOutsets() && !style()->hasOutline())
4107         return;
4108
4109     bool isFlipped = style()->isFlippedBlocksWritingMode();
4110     bool isHorizontal = isHorizontalWritingMode();
4111
4112     LayoutRect borderBox = borderBoxRect();
4113     LayoutUnit overflowMinX = borderBox.x();
4114     LayoutUnit overflowMaxX = borderBox.maxX();
4115     LayoutUnit overflowMinY = borderBox.y();
4116     LayoutUnit overflowMaxY = borderBox.maxY();
4117
4118     // Compute box-shadow overflow first.
4119     if (style()->boxShadow()) {
4120         LayoutUnit shadowLeft;
4121         LayoutUnit shadowRight;
4122         LayoutUnit shadowTop;
4123         LayoutUnit shadowBottom;
4124         style()->getBoxShadowExtent(shadowTop, shadowRight, shadowBottom, shadowLeft);
4125
4126         // In flipped blocks writing modes such as vertical-rl, the physical right shadow value is actually at the lower x-coordinate.
4127         overflowMinX = borderBox.x() + ((!isFlipped || isHorizontal) ? shadowLeft : -shadowRight);
4128         overflowMaxX = borderBox.maxX() + ((!isFlipped || isHorizontal) ? shadowRight : -shadowLeft);
4129         overflowMinY = borderBox.y() + ((!isFlipped || !isHorizontal) ? shadowTop : -shadowBottom);
4130         overflowMaxY = borderBox.maxY() + ((!isFlipped || !isHorizontal) ? shadowBottom : -shadowTop);
4131     }
4132
4133     // Now compute border-image-outset overflow.
4134     if (style()->hasBorderImageOutsets()) {
4135         LayoutBoxExtent borderOutsets = style()->borderImageOutsets();
4136
4137         // In flipped blocks writing modes, the physical sides are inverted. For example in vertical-rl, the right
4138         // border is at the lower x coordinate value.
4139         overflowMinX = min(overflowMinX, borderBox.x() - ((!isFlipped || isHorizontal) ? borderOutsets.left() : borderOutsets.right()));
4140         overflowMaxX = max(overflowMaxX, borderBox.maxX() + ((!isFlipped || isHorizontal) ? borderOutsets.right() : borderOutsets.left()));
4141         overflowMinY = min(overflowMinY, borderBox.y() - ((!isFlipped || !isHorizontal) ? borderOutsets.top() : borderOutsets.bottom()));
4142         overflowMaxY = max(overflowMaxY, borderBox.maxY() + ((!isFlipped || !isHorizontal) ? borderOutsets.bottom() : borderOutsets.top()));
4143     }
4144
4145     if (style()->hasOutline()) {
4146         LayoutUnit outlineSize = style()->outlineSize();
4147
4148         overflowMinX = min(overflowMinX, borderBox.x() - outlineSize);
4149         overflowMaxX = max(overflowMaxX, borderBox.maxX() + outlineSize);
4150         overflowMinY = min(overflowMinY, borderBox.y() - outlineSize);
4151         overflowMaxY = max(overflowMaxY, borderBox.maxY() + outlineSize);
4152     }
4153
4154     // Add in the final overflow with shadows, outsets and outline combined.
4155     LayoutRect visualEffectOverflow(overflowMinX, overflowMinY, overflowMaxX - overflowMinX, overflowMaxY - overflowMinY);
4156     addVisualOverflow(visualEffectOverflow);
4157 }
4158
4159 void RenderBox::addOverflowFromChild(RenderBox* child, const LayoutSize& delta)
4160 {
4161     // Never allow flow threads to propagate overflow up to a parent.
4162     if (child->isRenderFlowThread())
4163         return;
4164
4165     // Only propagate layout overflow from the child if the child isn't clipping its overflow.  If it is, then
4166     // its overflow is internal to it, and we don't care about it.  layoutOverflowRectForPropagation takes care of this
4167     // and just propagates the border box rect instead.
4168     LayoutRect childLayoutOverflowRect = child->layoutOverflowRectForPropagation(style());
4169     childLayoutOverflowRect.move(delta);
4170     addLayoutOverflow(childLayoutOverflowRect);
4171
4172     // Add in visual overflow from the child.  Even if the child clips its overflow, it may still
4173     // have visual overflow of its own set from box shadows or reflections.  It is unnecessary to propagate this
4174     // overflow if we are clipping our own overflow.
4175     if (child->hasSelfPaintingLayer())
4176         return;
4177     LayoutRect childVisualOverflowRect = child->visualOverflowRectForPropagation(style());
4178     childVisualOverflowRect.move(delta);
4179     addContentsVisualOverflow(childVisualOverflowRect);
4180 }
4181
4182 void RenderBox::addLayoutOverflow(const LayoutRect& rect)
4183 {
4184     LayoutRect clientBox = noOverflowRect();
4185     if (clientBox.contains(rect) || rect.isEmpty())
4186         return;
4187
4188     // For overflow clip objects, we don't want to propagate overflow into unreachable areas.
4189     LayoutRect overflowRect(rect);
4190     if (hasOverflowClip() || isRenderView()) {
4191         // Overflow is in the block's coordinate space and thus is flipped for horizontal-bt and vertical-rl
4192         // writing modes.  At this stage that is actually a simplification, since we can treat horizontal-tb/bt as the same
4193         // and vertical-lr/rl as the same.
4194         bool hasTopOverflow = !style()->isLeftToRightDirection() && !isHorizontalWritingMode();
4195         bool hasLeftOverflow = !style()->isLeftToRightDirection() && isHorizontalWritingMode();
4196         if (isFlexibleBox() && style()->isReverseFlexDirection()) {
4197             RenderFlexibleBox* flexibleBox = toRenderFlexibleBox(this);
4198             if (flexibleBox->isHorizontalFlow())
4199                 hasLeftOverflow = true;
4200             else
4201                 hasTopOverflow = true;
4202         }
4203
4204         if (!hasTopOverflow)
4205             overflowRect.shiftYEdgeTo(max(overflowRect.y(), clientBox.y()));
4206         else
4207             overflowRect.shiftMaxYEdgeTo(min(overflowRect.maxY(), clientBox.maxY()));
4208         if (!hasLeftOverflow)
4209             overflowRect.shiftXEdgeTo(max(overflowRect.x(), clientBox.x()));
4210         else
4211             overflowRect.shiftMaxXEdgeTo(min(overflowRect.maxX(), clientBox.maxX()));
4212
4213         // Now re-test with the adjusted rectangle and see if it has become unreachable or fully
4214         // contained.
4215         if (clientBox.contains(overflowRect) || overflowRect.isEmpty())
4216             return;
4217     }
4218
4219     if (!m_overflow)
4220         m_overflow = adoptPtr(new RenderOverflow(clientBox, borderBoxRect()));
4221
4222     m_overflow->addLayoutOverflow(overflowRect);
4223 }
4224
4225 void RenderBox::addVisualOverflow(const LayoutRect& rect)
4226 {
4227     LayoutRect borderBox = borderBoxRect();
4228     if (borderBox.contains(rect) || rect.isEmpty())
4229         return;
4230
4231     if (!m_overflow)
4232         m_overflow = adoptPtr(new RenderOverflow(noOverflowRect(), borderBox));
4233
4234     m_overflow->addVisualOverflow(rect);
4235 }
4236
4237 void RenderBox::addContentsVisualOverflow(const LayoutRect& rect)
4238 {
4239     if (!hasOverflowClip()) {
4240         addVisualOverflow(rect);
4241         return;
4242     }
4243
4244     if (!m_overflow)
4245         m_overflow = adoptPtr(new RenderOverflow(noOverflowRect(), borderBoxRect()));
4246     m_overflow->addContentsVisualOverflow(rect);
4247 }
4248
4249 void RenderBox::clearLayoutOverflow()
4250 {
4251     if (!m_overflow)
4252         return;
4253
4254     if (!hasVisualOverflow() && contentsVisualOverflowRect().isEmpty()) {
4255         m_overflow.clear();
4256         return;
4257     }
4258
4259     m_overflow->setLayoutOverflow(noOverflowRect());
4260 }
4261
4262 inline static bool percentageLogicalHeightIsResolvable(const RenderBox* box)
4263 {
4264     return RenderBox::percentageLogicalHeightIsResolvableFromBlock(box->containingBlock(), box->isOutOfFlowPositioned());
4265 }
4266
4267 bool RenderBox::percentageLogicalHeightIsResolvableFromBlock(const RenderBlock* containingBlock, bool isOutOfFlowPositioned)
4268 {
4269     // In quirks mode, blocks with auto height are skipped, and we keep looking for an enclosing
4270     // block that may have a specified height and then use it. In strict mode, this violates the
4271     // specification, which states that percentage heights just revert to auto if the containing
4272     // block has an auto height. We still skip anonymous containing blocks in both modes, though, and look
4273     // only at explicit containers.
4274     const RenderBlock* cb = containingBlock;
4275     bool inQuirksMode = cb->document().inQuirksMode();
4276     while (!cb->isRenderView() && !cb->isBody() && !cb->isTableCell() && !cb->isOutOfFlowPositioned() && cb->style()->logicalHeight().isAuto()) {
4277         if (!inQuirksMode && !cb->isAnonymousBlock())
4278             break;
4279         cb = cb->containingBlock();
4280     }
4281
4282     // A positioned element that specified both top/bottom or that specifies height should be treated as though it has a height
4283     // explicitly specified that can be used for any percentage computations.
4284     // FIXME: We can't just check top/bottom here.
4285     // https://bugs.webkit.org/show_bug.cgi?id=46500
4286     bool isOutOfFlowPositionedWithSpecifiedHeight = cb->isOutOfFlowPositioned() && (!cb->style()->logicalHeight().isAuto() || (!cb->style()->top().isAuto() && !cb->style()->bottom().isAuto()));
4287
4288     // Table cells violate what the CSS spec says to do with heights.  Basically we
4289     // don't care if the cell specified a height or not.  We just always make ourselves
4290     // be a percentage of the cell's current content height.
4291     if (cb->isTableCell())
4292         return true;
4293
4294     // Otherwise we only use our percentage height if our containing block had a specified
4295     // height.
4296     if (cb->style()->logicalHeight().isFixed())
4297         return true;
4298     if (cb->style()->logicalHeight().isPercent() && !isOutOfFlowPositionedWithSpecifiedHeight)
4299         return percentageLogicalHeightIsResolvableFromBlock(cb->containingBlock(), cb->isOutOfFlowPositioned());
4300     if (cb->isRenderView() || inQuirksMode || isOutOfFlowPositionedWithSpecifiedHeight)
4301         return true;
4302     if (cb->isDocumentElement() && isOutOfFlowPositioned) {
4303         // Match the positioned objects behavior, which is that positioned objects will fill their viewport
4304         // always.  Note we could only hit this case by recurring into computePercentageLogicalHeight on a positioned containing block.
4305         return true;
4306     }
4307
4308     return false;
4309 }
4310
4311 bool RenderBox::hasUnsplittableScrollingOverflow() const
4312 {
4313     // We will paginate as long as we don't scroll overflow in the pagination direction.
4314     bool isHorizontal = isHorizontalWritingMode();
4315     if ((isHorizontal && !scrollsOverflowY()) || (!isHorizontal && !scrollsOverflowX()))
4316         return false;
4317
4318     // We do have overflow. We'll still be willing to paginate as long as the block
4319     // has auto logical height, auto or undefined max-logical-height and a zero or auto min-logical-height.
4320     // Note this is just a heuristic, and it's still possible to have overflow under these
4321     // conditions, but it should work out to be good enough for common cases. Paginating overflow
4322     // with scrollbars present is not the end of the world and is what we used to do in the old model anyway.
4323     return !style()->logicalHeight().isIntrinsicOrAuto()
4324         || (!style()->logicalMaxHeight().isIntrinsicOrAuto() && !style()->logicalMaxHeight().isUndefined() && (!style()->logicalMaxHeight().isPercent() || percentageLogicalHeightIsResolvable(this)))
4325         || (!style()->logicalMinHeight().isIntrinsicOrAuto() && style()->logicalMinHeight().isPositive() && (!style()->logicalMinHeight().isPercent() || percentageLogicalHeightIsResolvable(this)));
4326 }
4327
4328 bool RenderBox::isUnsplittableForPagination() const
4329 {
4330     return isReplaced() || hasUnsplittableScrollingOverflow() || (parent() && isWritingModeRoot());
4331 }
4332
4333 LayoutUnit RenderBox::lineHeight(bool /*firstLine*/, LineDirectionMode direction, LinePositionMode /*linePositionMode*/) const
4334 {
4335     if (isReplaced())
4336         return direction == HorizontalLine ? m_marginBox.top() + height() + m_marginBox.bottom() : m_marginBox.right() + width() + m_marginBox.left();
4337     return 0;
4338 }
4339
4340 int RenderBox::baselinePosition(FontBaseline baselineType, bool /*firstLine*/, LineDirectionMode direction, LinePositionMode linePositionMode) const
4341 {
4342     ASSERT(linePositionMode == PositionOnContainingLine);
4343     if (isReplaced()) {
4344         int result = direction == HorizontalLine ? m_marginBox.top() + height() + m_marginBox.bottom() : m_marginBox.right() + width() + m_marginBox.left();
4345         if (baselineType == AlphabeticBaseline)
4346             return result;
4347         return result - result / 2;
4348     }
4349     return 0;
4350 }
4351
4352
4353 RenderLayer* RenderBox::enclosingFloatPaintingLayer() const
4354 {
4355     const RenderObject* curr = this;
4356     while (curr) {
4357         RenderLayer* layer = curr->hasLayer() && curr->isBox() ? toRenderBox(curr)->layer() : 0;
4358         if (layer && layer->isSelfPaintingLayer())
4359             return layer;
4360         curr = curr->parent();
4361     }
4362     return 0;
4363 }
4364
4365 LayoutRect RenderBox::logicalVisualOverflowRectForPropagation(RenderStyle* parentStyle) const
4366 {
4367     LayoutRect rect = visualOverflowRectForPropagation(parentStyle);
4368     if (!parentStyle->isHorizontalWritingMode())
4369         return rect.transposedRect();
4370     return rect;
4371 }
4372
4373 LayoutRect RenderBox::visualOverflowRectForPropagation(RenderStyle* parentStyle) const
4374 {
4375     // If the writing modes of the child and parent match, then we don't have to
4376     // do anything fancy. Just return the result.
4377     LayoutRect rect = visualOverflowRect();
4378     if (parentStyle->writingMode() == style()->writingMode())
4379         return rect;
4380
4381     // We are putting ourselves into our parent's coordinate space.  If there is a flipped block mismatch
4382     // in a particular axis, then we have to flip the rect along that axis.
4383     if (style()->writingMode() == RightToLeftWritingMode || parentStyle->writingMode() == RightToLeftWritingMode)
4384         rect.setX(width() - rect.maxX());
4385     else if (style()->writingMode() == BottomToTopWritingMode || parentStyle->writingMode() == BottomToTopWritingMode)
4386         rect.setY(height() - rect.maxY());
4387
4388     return rect;
4389 }
4390
4391 LayoutRect RenderBox::logicalLayoutOverflowRectForPropagation(RenderStyle* parentStyle) const
4392 {
4393     LayoutRect rect = layoutOverflowRectForPropagation(parentStyle);
4394     if (!parentStyle->isHorizontalWritingMode())
4395         return rect.transposedRect();
4396     return rect;
4397 }
4398
4399 LayoutRect RenderBox::layoutOverflowRectForPropagation(RenderStyle* parentStyle) const
4400 {
4401     // Only propagate interior layout overflow if we don't clip it.
4402     LayoutRect rect = borderBoxRect();
4403     // We want to include the margin, but only when it adds height. Quirky margins don't contribute height
4404     // nor do the margins of self-collapsing blocks.
4405     if (!style()->hasMarginAfterQuirk() && !isSelfCollapsingBlock())
4406         rect.expand(isHorizontalWritingMode() ? LayoutSize(LayoutUnit(), marginAfter()) : LayoutSize(marginAfter(), LayoutUnit()));
4407
4408     if (!hasOverflowClip())
4409         rect.unite(layoutOverflowRect());
4410
4411     bool hasTransform = hasLayer() && layer()->transform();
4412     if (isInFlowPositioned() || hasTransform) {
4413         // If we are relatively positioned or if we have a transform, then we have to convert
4414         // this rectangle into physical coordinates, apply relative positioning and transforms
4415         // to it, and then convert it back.
4416         flipForWritingMode(rect);
4417
4418         if (hasTransform)
4419             rect = layer()->currentTransform().mapRect(rect);
4420
4421         if (isInFlowPositioned())
4422             rect.move(offsetForInFlowPosition());
4423
4424         // Now we need to flip back.
4425         flipForWritingMode(rect);
4426     }
4427
4428     // If the writing modes of the child and parent match, then we don't have to
4429     // do anything fancy. Just return the result.
4430     if (parentStyle->writingMode() == style()->writingMode())
4431         return rect;
4432
4433     // We are putting ourselves into our parent's coordinate space.  If there is a flipped block mismatch
4434     // in a particular axis, then we have to flip the rect along that axis.
4435     if (style()->writingMode() == RightToLeftWritingMode || parentStyle->writingMode() == RightToLeftWritingMode)
4436         rect.setX(width() - rect.maxX());
4437     else if (style()->writingMode() == BottomToTopWritingMode || parentStyle->writingMode() == BottomToTopWritingMode)
4438         rect.setY(height() - rect.maxY());
4439
4440     return rect;
4441 }
4442
4443 LayoutRect RenderBox::noOverflowRect() const
4444 {
4445     // Because of the special coordinate system used for overflow rectangles and many other
4446     // rectangles (not quite logical, not quite physical), we need to flip the block progression
4447     // coordinate in vertical-rl and horizontal-bt writing modes. In other words, the rectangle
4448     // returned is physical, except for the block direction progression coordinate (y in horizontal
4449     // writing modes, x in vertical writing modes), which is always "logical top". Apart from the
4450     // flipping, this method does the same as clientBoxRect().
4451
4452     const int scrollBarWidth = verticalScrollbarWidth();
4453     const int scrollBarHeight = horizontalScrollbarHeight();
4454     LayoutUnit left = borderLeft() + (style()->shouldPlaceBlockDirectionScrollbarOnLogicalLeft() ? scrollBarWidth : 0);
4455     LayoutUnit top = borderTop();
4456     LayoutUnit right = borderRight();
4457     LayoutUnit bottom = borderBottom();
4458     LayoutRect rect(left, top, width() - left - right, height() - top - bottom);
4459     flipForWritingMode(rect);
4460     // Subtract space occupied by scrollbars. Order is important here: first flip, then subtract
4461     // scrollbars. This may seem backwards and weird, since one would think that a horizontal
4462     // scrollbar at the physical bottom in horizontal-bt ought to be at the logical top (physical
4463     // bottom), between the logical top (physical bottom) border and the logical top (physical
4464     // bottom) padding. But this is how the rest of the code expects us to behave. This is highly
4465     // related to https://bugs.webkit.org/show_bug.cgi?id=76129
4466     // FIXME: when the above mentioned bug is fixed, it should hopefully be possible to call
4467     // clientBoxRect() or paddingBoxRect() in this method, rather than fiddling with the edges on
4468     // our own.
4469     if (style()->shouldPlaceBlockDirectionScrollbarOnLogicalLeft())
4470         rect.contract(0, scrollBarHeight);
4471     else
4472         rect.contract(scrollBarWidth, scrollBarHeight);
4473     return rect;
4474 }
4475
4476 LayoutRect RenderBox::overflowRectForPaintRejection() const
4477 {
4478     LayoutRect overflowRect = visualOverflowRect();
4479     if (!m_overflow || !usesCompositedScrolling())
4480         return overflowRect;
4481
4482     overflowRect.unite(layoutOverflowRect());
4483     overflowRect.move(-scrolledContentOffset());
4484     return overflowRect;
4485 }
4486
4487 LayoutUnit RenderBox::offsetLeft() const
4488 {
4489     return adjustedPositionRelativeToOffsetParent(topLeftLocation()).x();
4490 }
4491
4492 LayoutUnit RenderBox::offsetTop() const
4493 {
4494     return adjustedPositionRelativeToOffsetParent(topLeftLocation()).y();
4495 }
4496
4497 LayoutPoint RenderBox::flipForWritingModeForChild(const RenderBox* child, const LayoutPoint& point) const
4498 {
4499     if (!style()->isFlippedBlocksWritingMode())
4500         return point;
4501
4502     // The child is going to add in its x() and y(), so we have to make sure it ends up in
4503     // the right place.
4504     if (isHorizontalWritingMode())
4505         return LayoutPoint(point.x(), point.y() + height() - child->height() - (2 * child->y()));
4506     return LayoutPoint(point.x() + width() - child->width() - (2 * child->x()), point.y());
4507 }
4508
4509 void RenderBox::flipForWritingMode(LayoutRect& rect) const
4510 {
4511     if (!style()->isFlippedBlocksWritingMode())
4512         return;
4513
4514     if (isHorizontalWritingMode())
4515         rect.setY(height() - rect.maxY());
4516     else
4517         rect.setX(width() - rect.maxX());
4518 }
4519
4520 LayoutUnit RenderBox::flipForWritingMode(LayoutUnit position) const
4521 {
4522     if (!style()->isFlippedBlocksWritingMode())
4523         return position;
4524     return logicalHeight() - position;
4525 }
4526
4527 LayoutPoint RenderBox::flipForWritingMode(const LayoutPoint& position) const
4528 {
4529     if (!style()->isFlippedBlocksWritingMode())
4530         return position;
4531     return isHorizontalWritingMode() ? LayoutPoint(position.x(), height() - position.y()) : LayoutPoint(width() - position.x(), position.y());
4532 }
4533
4534 LayoutPoint RenderBox::flipForWritingModeIncludingColumns(const LayoutPoint& point) const
4535 {
4536     if (!hasColumns() || !style()->isFlippedBlocksWritingMode())
4537         return flipForWritingMode(point);
4538     return toRenderBlock(this)->flipForWritingModeIncludingColumns(point);
4539 }
4540
4541 LayoutSize RenderBox::flipForWritingMode(const LayoutSize& offset) const
4542 {
4543     if (!style()->isFlippedBlocksWritingMode())
4544         return offset;
4545     return isHorizontalWritingMode() ? LayoutSize(offset.width(), height() - offset.height()) : LayoutSize(width() - offset.width(), offset.height());
4546 }
4547
4548 FloatPoint RenderBox::flipForWritingMode(const FloatPoint& position) const
4549 {
4550     if (!style()->isFlippedBlocksWritingMode())
4551         return position;
4552     return isHorizontalWritingMode() ? FloatPoint(position.x(), height() - position.y()) : FloatPoint(width() - position.x(), position.y());
4553 }
4554
4555 void RenderBox::flipForWritingMode(FloatRect& rect) const
4556 {
4557     if (!style()->isFlippedBlocksWritingMode())
4558         return;
4559
4560     if (isHorizontalWritingMode())
4561         rect.setY(height() - rect.maxY());
4562     else
4563         rect.setX(width() - rect.maxX());
4564 }
4565
4566 LayoutPoint RenderBox::topLeftLocation() const
4567 {
4568     RenderBlock* containerBlock = containingBlock();
4569     if (!containerBlock || containerBlock == this)
4570         return location();
4571     return containerBlock->flipForWritingModeForChild(this, location());
4572 }
4573
4574 LayoutSize RenderBox::topLeftLocationOffset() const
4575 {
4576     RenderBlock* containerBlock = containingBlock();
4577     if (!containerBlock || containerBlock == this)
4578         return locationOffset();
4579
4580     LayoutRect rect(frameRect());
4581     containerBlock->flipForWritingMode(rect); // FIXME: This is wrong if we are an absolutely positioned object enclosed by a relative-positioned inline.
4582     return LayoutSize(rect.x(), rect.y());
4583 }
4584
4585 bool RenderBox::hasRelativeLogicalHeight() const
4586 {
4587     return style()->logicalHeight().isPercent()
4588         || style()->logicalMinHeight().isPercent()
4589         || style()->logicalMaxHeight().isPercent();
4590 }
4591
4592 static void markBoxForRelayoutAfterSplit(RenderBox* box)
4593 {
4594     // FIXME: The table code should handle that automatically. If not,
4595     // we should fix it and remove the table part checks.
4596     if (box->isTable()) {
4597         // Because we may have added some sections with already computed column structures, we need to
4598         // sync the table structure with them now. This avoids crashes when adding new cells to the table.
4599         toRenderTable(box)->forceSectionsRecalc();
4600     } else if (box->isTableSection())
4601         toRenderTableSection(box)->setNeedsCellRecalc();
4602
4603     box->setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation();
4604 }
4605
4606 RenderObject* RenderBox::splitAnonymousBoxesAroundChild(RenderObject* beforeChild)
4607 {
4608     bool didSplitParentAnonymousBoxes = false;
4609
4610     while (beforeChild->parent() != this) {
4611         RenderBox* boxToSplit = toRenderBox(beforeChild->parent());
4612         if (boxToSplit->slowFirstChild() != beforeChild && boxToSplit->isAnonymous()) {
4613             didSplitParentAnonymousBoxes = true;
4614
4615             // We have to split the parent box into two boxes and move children
4616             // from |beforeChild| to end into the new post box.
4617             RenderBox* postBox = boxToSplit->createAnonymousBoxWithSameTypeAs(this);
4618             postBox->setChildrenInline(boxToSplit->childrenInline());
4619             RenderBox* parentBox = toRenderBox(boxToSplit->parent());
4620             // We need to invalidate the |parentBox| before inserting the new node
4621             // so that the table repainting logic knows the structure is dirty.
4622             // See for example RenderTableCell:clippedOverflowRectForPaintInvalidation.
4623             markBoxForRelayoutAfterSplit(parentBox);
4624             parentBox->virtualChildren()->insertChildNode(parentBox, postBox, boxToSplit->nextSibling());
4625             boxToSplit->moveChildrenTo(postBox, beforeChild, 0, true);
4626
4627             markBoxForRelayoutAfterSplit(boxToSplit);
4628             markBoxForRelayoutAfterSplit(postBox);
4629
4630             beforeChild = postBox;
4631         } else
4632             beforeChild = boxToSplit;
4633     }
4634
4635     if (didSplitParentAnonymousBoxes)
4636         markBoxForRelayoutAfterSplit(this);
4637
4638     ASSERT(beforeChild->parent() == this);
4639     return beforeChild;
4640 }
4641
4642 LayoutUnit RenderBox::offsetFromLogicalTopOfFirstPage() const
4643 {
4644     LayoutState* layoutState = view()->layoutState();
4645     if (layoutState && !layoutState->isPaginated())
4646         return 0;
4647
4648     if (!layoutState && !flowThreadContainingBlock())
4649         return 0;
4650
4651     RenderBlock* containerBlock = containingBlock();
4652     return containerBlock->offsetFromLogicalTopOfFirstPage() + logicalTop();
4653 }
4654
4655 } // namespace WebCore