src/third_party/WebKit/Source/platform/scroll/ScrollbarTheme.cpp

   1 /*
   2  * Copyright (C) 2011 Apple Inc. All Rights Reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27 #include "platform/scroll/ScrollbarTheme.h"
  28
  29 #include "platform/PlatformMouseEvent.h"
  30 #include "platform/RuntimeEnabledFeatures.h"
  31 #include "platform/graphics/Color.h"
  32 #include "platform/graphics/GraphicsContext.h"
  33 #include "platform/scroll/ScrollbarThemeClient.h"
  34 #include "platform/scroll/ScrollbarThemeMock.h"
  35 #include "platform/scroll/ScrollbarThemeOverlayMock.h"
  36 #include "public/platform/Platform.h"
  37 #include "public/platform/WebPoint.h"
  38 #include "public/platform/WebRect.h"
  39 #include "public/platform/WebScrollbarBehavior.h"
  40
  41 #if !OS(MACOSX)
  42 #include "public/platform/WebRect.h"
  43 #include "public/platform/WebThemeEngine.h"
  44 #endif
  45
  46 namespace blink {
  47
  48 bool ScrollbarTheme::gMockScrollbarsEnabled = false;
  49
  50 bool ScrollbarTheme::paint(ScrollbarThemeClient* scrollbar, GraphicsContext* graphicsContext, const IntRect& damageRect)
  51 {
  52     // Create the ScrollbarControlPartMask based on the damageRect
  53     ScrollbarControlPartMask scrollMask = NoPart;
  54
  55     IntRect backButtonStartPaintRect;
  56     IntRect backButtonEndPaintRect;
  57     IntRect forwardButtonStartPaintRect;
  58     IntRect forwardButtonEndPaintRect;
  59     if (hasButtons(scrollbar)) {
  60         backButtonStartPaintRect = backButtonRect(scrollbar, BackButtonStartPart, true);
  61         if (damageRect.intersects(backButtonStartPaintRect))
  62             scrollMask |= BackButtonStartPart;
  63         backButtonEndPaintRect = backButtonRect(scrollbar, BackButtonEndPart, true);
  64         if (damageRect.intersects(backButtonEndPaintRect))
  65             scrollMask |= BackButtonEndPart;
  66         forwardButtonStartPaintRect = forwardButtonRect(scrollbar, ForwardButtonStartPart, true);
  67         if (damageRect.intersects(forwardButtonStartPaintRect))
  68             scrollMask |= ForwardButtonStartPart;
  69         forwardButtonEndPaintRect = forwardButtonRect(scrollbar, ForwardButtonEndPart, true);
  70         if (damageRect.intersects(forwardButtonEndPaintRect))
  71             scrollMask |= ForwardButtonEndPart;
  72     }
  73
  74     IntRect startTrackRect;
  75     IntRect thumbRect;
  76     IntRect endTrackRect;
  77     IntRect trackPaintRect = trackRect(scrollbar, true);
  78     if (damageRect.intersects(trackPaintRect))
  79         scrollMask |= TrackBGPart;
  80     bool thumbPresent = hasThumb(scrollbar);
  81     if (thumbPresent) {
  82         IntRect track = trackRect(scrollbar);
  83         splitTrack(scrollbar, track, startTrackRect, thumbRect, endTrackRect);
  84         if (damageRect.intersects(thumbRect))
  85             scrollMask |= ThumbPart;
  86         if (damageRect.intersects(startTrackRect))
  87             scrollMask |= BackTrackPart;
  88         if (damageRect.intersects(endTrackRect))
  89             scrollMask |= ForwardTrackPart;
  90     }
  91
  92     // Paint the scrollbar background (only used by custom CSS scrollbars).
  93     paintScrollbarBackground(graphicsContext, scrollbar);
  94
  95     // Paint the back and forward buttons.
  96     if (scrollMask & BackButtonStartPart)
  97         paintButton(graphicsContext, scrollbar, backButtonStartPaintRect, BackButtonStartPart);
  98     if (scrollMask & BackButtonEndPart)
  99         paintButton(graphicsContext, scrollbar, backButtonEndPaintRect, BackButtonEndPart);
 100     if (scrollMask & ForwardButtonStartPart)
 101         paintButton(graphicsContext, scrollbar, forwardButtonStartPaintRect, ForwardButtonStartPart);
 102     if (scrollMask & ForwardButtonEndPart)
 103         paintButton(graphicsContext, scrollbar, forwardButtonEndPaintRect, ForwardButtonEndPart);
 104
 105     if (scrollMask & TrackBGPart)
 106         paintTrackBackground(graphicsContext, scrollbar, trackPaintRect);
 107
 108     if ((scrollMask & ForwardTrackPart) || (scrollMask & BackTrackPart)) {
 109         // Paint the track pieces above and below the thumb.
 110         if (scrollMask & BackTrackPart)
 111             paintTrackPiece(graphicsContext, scrollbar, startTrackRect, BackTrackPart);
 112         if (scrollMask & ForwardTrackPart)
 113             paintTrackPiece(graphicsContext, scrollbar, endTrackRect, ForwardTrackPart);
 114
 115         paintTickmarks(graphicsContext, scrollbar, trackPaintRect);
 116     }
 117
 118     // Paint the thumb.
 119     if (scrollMask & ThumbPart)
 120         paintThumb(graphicsContext, scrollbar, thumbRect);
 121
 122     return true;
 123 }
 124
 125 ScrollbarPart ScrollbarTheme::hitTest(ScrollbarThemeClient* scrollbar, const IntPoint& position)
 126 {
 127     ScrollbarPart result = NoPart;
 128     if (!scrollbar->enabled())
 129         return result;
 130
 131     IntPoint testPosition = scrollbar->convertFromContainingWindow(position);
 132     testPosition.move(scrollbar->x(), scrollbar->y());
 133
 134     if (!scrollbar->frameRect().contains(testPosition))
 135         return NoPart;
 136
 137     result = ScrollbarBGPart;
 138
 139     IntRect track = trackRect(scrollbar);
 140     if (track.contains(testPosition)) {
 141         IntRect beforeThumbRect;
 142         IntRect thumbRect;
 143         IntRect afterThumbRect;
 144         splitTrack(scrollbar, track, beforeThumbRect, thumbRect, afterThumbRect);
 145         if (thumbRect.contains(testPosition))
 146             result = ThumbPart;
 147         else if (beforeThumbRect.contains(testPosition))
 148             result = BackTrackPart;
 149         else if (afterThumbRect.contains(testPosition))
 150             result = ForwardTrackPart;
 151         else
 152             result = TrackBGPart;
 153     } else if (backButtonRect(scrollbar, BackButtonStartPart).contains(testPosition)) {
 154         result = BackButtonStartPart;
 155     } else if (backButtonRect(scrollbar, BackButtonEndPart).contains(testPosition)) {
 156         result = BackButtonEndPart;
 157     } else if (forwardButtonRect(scrollbar, ForwardButtonStartPart).contains(testPosition)) {
 158         result = ForwardButtonStartPart;
 159     } else if (forwardButtonRect(scrollbar, ForwardButtonEndPart).contains(testPosition)) {
 160         result = ForwardButtonEndPart;
 161     }
 162     return result;
 163 }
 164
 165 void ScrollbarTheme::invalidatePart(ScrollbarThemeClient* scrollbar, ScrollbarPart part)
 166 {
 167     if (part == NoPart)
 168         return;
 169
 170     IntRect result;
 171     switch (part) {
 172     case BackButtonStartPart:
 173         result = backButtonRect(scrollbar, BackButtonStartPart, true);
 174         break;
 175     case BackButtonEndPart:
 176         result = backButtonRect(scrollbar, BackButtonEndPart, true);
 177         break;
 178     case ForwardButtonStartPart:
 179         result = forwardButtonRect(scrollbar, ForwardButtonStartPart, true);
 180         break;
 181     case ForwardButtonEndPart:
 182         result = forwardButtonRect(scrollbar, ForwardButtonEndPart, true);
 183         break;
 184     case TrackBGPart:
 185         result = trackRect(scrollbar, true);
 186         break;
 187     case ScrollbarBGPart:
 188         result = scrollbar->frameRect();
 189         break;
 190     default: {
 191         IntRect beforeThumbRect, thumbRect, afterThumbRect;
 192         splitTrack(scrollbar, trackRect(scrollbar), beforeThumbRect, thumbRect, afterThumbRect);
 193         if (part == BackTrackPart)
 194             result = beforeThumbRect;
 195         else if (part == ForwardTrackPart)
 196             result = afterThumbRect;
 197         else
 198             result = thumbRect;
 199     }
 200     }
 201     result.moveBy(-scrollbar->location());
 202     scrollbar->invalidateRect(result);
 203 }
 204
 205 void ScrollbarTheme::paintScrollCorner(GraphicsContext* context, const IntRect& cornerRect)
 206 {
 207     if (cornerRect.isEmpty())
 208         return;
 209
 210 #if OS(MACOSX)
 211     context->fillRect(cornerRect, Color::white);
 212 #else
 213     blink::Platform::current()->themeEngine()->paint(context->canvas(), blink::WebThemeEngine::PartScrollbarCorner, blink::WebThemeEngine::StateNormal, blink::WebRect(cornerRect), 0);
 214 #endif
 215 }
 216
 217 void ScrollbarTheme::paintOverhangBackground(GraphicsContext* context, const IntRect& horizontalOverhangRect, const IntRect& verticalOverhangRect, const IntRect& dirtyRect)
 218 {
 219     context->setFillColor(Color::white);
 220     if (!horizontalOverhangRect.isEmpty())
 221         context->fillRect(intersection(horizontalOverhangRect, dirtyRect));
 222     if (!verticalOverhangRect.isEmpty())
 223         context->fillRect(intersection(verticalOverhangRect, dirtyRect));
 224 }
 225
 226 bool ScrollbarTheme::shouldCenterOnThumb(ScrollbarThemeClient* scrollbar, const PlatformMouseEvent& evt)
 227 {
 228     return blink::Platform::current()->scrollbarBehavior()->shouldCenterOnThumb(static_cast<blink::WebScrollbarBehavior::Button>(evt.button()), evt.shiftKey(), evt.altKey());
 229 }
 230
 231 bool ScrollbarTheme::shouldSnapBackToDragOrigin(ScrollbarThemeClient* scrollbar, const PlatformMouseEvent& evt)
 232 {
 233     IntPoint mousePosition = scrollbar->convertFromContainingWindow(evt.position());
 234     mousePosition.move(scrollbar->x(), scrollbar->y());
 235     return blink::Platform::current()->scrollbarBehavior()->shouldSnapBackToDragOrigin(mousePosition, trackRect(scrollbar), scrollbar->orientation() == HorizontalScrollbar);
 236 }
 237
 238 // Returns the size represented by track taking into account scrolling past
 239 // the end of the document.
 240 static float usedTotalSize(ScrollbarThemeClient* scrollbar)
 241 {
 242     float overhangAtStart = -scrollbar->currentPos();
 243     float overhangAtEnd = scrollbar->currentPos() + scrollbar->visibleSize() - scrollbar->totalSize();
 244     float overhang = std::max(0.0f, std::max(overhangAtStart, overhangAtEnd));
 245     return scrollbar->totalSize() + overhang;
 246 }
 247
 248 int ScrollbarTheme::thumbPosition(ScrollbarThemeClient* scrollbar)
 249 {
 250     if (scrollbar->enabled()) {
 251         float size = usedTotalSize(scrollbar) - scrollbar->visibleSize();
 252         // Avoid doing a floating point divide by zero and return 1 when usedTotalSize == visibleSize.
 253         if (!size)
 254             return 1;
 255         float pos = std::max(0.0f, scrollbar->currentPos()) * (trackLength(scrollbar) - thumbLength(scrollbar)) / size;
 256         return (pos < 1 && pos > 0) ? 1 : pos;
 257     }
 258     return 0;
 259 }
 260
 261 int ScrollbarTheme::thumbLength(ScrollbarThemeClient* scrollbar)
 262 {
 263     if (!scrollbar->enabled())
 264         return 0;
 265
 266     float overhang = 0;
 267     if (scrollbar->currentPos() < 0)
 268         overhang = -scrollbar->currentPos();
 269     else if (scrollbar->visibleSize() + scrollbar->currentPos() > scrollbar->totalSize())
 270         overhang = scrollbar->currentPos() + scrollbar->visibleSize() - scrollbar->totalSize();
 271     float proportion = (scrollbar->visibleSize() - overhang) / usedTotalSize(scrollbar);
 272     int trackLen = trackLength(scrollbar);
 273     int length = round(proportion * trackLen);
 274     length = std::max(length, minimumThumbLength(scrollbar));
 275     if (length > trackLen)
 276         length = 0; // Once the thumb is below the track length, it just goes away (to make more room for the track).
 277     return length;
 278 }
 279
 280 int ScrollbarTheme::trackPosition(ScrollbarThemeClient* scrollbar)
 281 {
 282     IntRect constrainedTrackRect = constrainTrackRectToTrackPieces(scrollbar, trackRect(scrollbar));
 283     return (scrollbar->orientation() == HorizontalScrollbar) ? constrainedTrackRect.x() - scrollbar->x() : constrainedTrackRect.y() - scrollbar->y();
 284 }
 285
 286 int ScrollbarTheme::trackLength(ScrollbarThemeClient* scrollbar)
 287 {
 288     IntRect constrainedTrackRect = constrainTrackRectToTrackPieces(scrollbar, trackRect(scrollbar));
 289     return (scrollbar->orientation() == HorizontalScrollbar) ? constrainedTrackRect.width() : constrainedTrackRect.height();
 290 }
 291
 292 IntRect ScrollbarTheme::thumbRect(ScrollbarThemeClient* scrollbar)
 293 {
 294     if (!hasThumb(scrollbar))
 295         return IntRect();
 296
 297     IntRect track = trackRect(scrollbar);
 298     IntRect startTrackRect;
 299     IntRect thumbRect;
 300     IntRect endTrackRect;
 301     splitTrack(scrollbar, track, startTrackRect, thumbRect, endTrackRect);
 302
 303     return thumbRect;
 304 }
 305
 306 int ScrollbarTheme::thumbThickness(ScrollbarThemeClient* scrollbar)
 307 {
 308     IntRect track = trackRect(scrollbar);
 309     return scrollbar->orientation() == HorizontalScrollbar ? track.height() : track.width();
 310 }
 311
 312 int ScrollbarTheme::minimumThumbLength(ScrollbarThemeClient* scrollbar)
 313 {
 314     return scrollbarThickness(scrollbar->controlSize());
 315 }
 316
 317 void ScrollbarTheme::splitTrack(ScrollbarThemeClient* scrollbar, const IntRect& unconstrainedTrackRect, IntRect& beforeThumbRect, IntRect& thumbRect, IntRect& afterThumbRect)
 318 {
 319     // This function won't even get called unless we're big enough to have some combination of these three rects where at least
 320     // one of them is non-empty.
 321     IntRect trackRect = constrainTrackRectToTrackPieces(scrollbar, unconstrainedTrackRect);
 322     int thumbPos = thumbPosition(scrollbar);
 323     if (scrollbar->orientation() == HorizontalScrollbar) {
 324         thumbRect = IntRect(trackRect.x() + thumbPos, trackRect.y(), thumbLength(scrollbar), scrollbar->height());
 325         beforeThumbRect = IntRect(trackRect.x(), trackRect.y(), thumbPos + thumbRect.width() / 2, trackRect.height());
 326         afterThumbRect = IntRect(trackRect.x() + beforeThumbRect.width(), trackRect.y(), trackRect.maxX() - beforeThumbRect.maxX(), trackRect.height());
 327     } else {
 328         thumbRect = IntRect(trackRect.x(), trackRect.y() + thumbPos, scrollbar->width(), thumbLength(scrollbar));
 329         beforeThumbRect = IntRect(trackRect.x(), trackRect.y(), trackRect.width(), thumbPos + thumbRect.height() / 2);
 330         afterThumbRect = IntRect(trackRect.x(), trackRect.y() + beforeThumbRect.height(), trackRect.width(), trackRect.maxY() - beforeThumbRect.maxY());
 331     }
 332 }
 333
 334 ScrollbarTheme* ScrollbarTheme::theme()
 335 {
 336     if (ScrollbarTheme::mockScrollbarsEnabled()) {
 337         if (RuntimeEnabledFeatures::overlayScrollbarsEnabled()) {
 338             DEFINE_STATIC_LOCAL(ScrollbarThemeOverlayMock, overlayMockTheme, ());
 339             return &overlayMockTheme;
 340         }
 341
 342         DEFINE_STATIC_LOCAL(ScrollbarThemeMock, mockTheme, ());
 343         return &mockTheme;
 344     }
 345     return nativeTheme();
 346 }
 347
 348 void ScrollbarTheme::setMockScrollbarsEnabled(bool flag)
 349 {
 350     gMockScrollbarsEnabled = flag;
 351 }
 352
 353 bool ScrollbarTheme::mockScrollbarsEnabled()
 354 {
 355     return gMockScrollbarsEnabled;
 356 }
 357
 358 }