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 WebCore {
  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     if (context->paintingDisabled())
 214         return;
 215     blink::Platform::current()->themeEngine()->paint(context->canvas(), blink::WebThemeEngine::PartScrollbarCorner, blink::WebThemeEngine::StateNormal, blink::WebRect(cornerRect), 0);
 216 #endif
 217 }
 218
 219 void ScrollbarTheme::paintOverhangBackground(GraphicsContext* context, const IntRect& horizontalOverhangRect, const IntRect& verticalOverhangRect, const IntRect& dirtyRect)
 220 {
 221     context->setFillColor(Color::white);
 222     if (!horizontalOverhangRect.isEmpty())
 223         context->fillRect(intersection(horizontalOverhangRect, dirtyRect));
 224     if (!verticalOverhangRect.isEmpty())
 225         context->fillRect(intersection(verticalOverhangRect, dirtyRect));
 226 }
 227
 228 bool ScrollbarTheme::shouldCenterOnThumb(ScrollbarThemeClient* scrollbar, const PlatformMouseEvent& evt)
 229 {
 230     return blink::Platform::current()->scrollbarBehavior()->shouldCenterOnThumb(static_cast<blink::WebScrollbarBehavior::Button>(evt.button()), evt.shiftKey(), evt.altKey());
 231 }
 232
 233 bool ScrollbarTheme::shouldSnapBackToDragOrigin(ScrollbarThemeClient* scrollbar, const PlatformMouseEvent& evt)
 234 {
 235     IntPoint mousePosition = scrollbar->convertFromContainingWindow(evt.position());
 236     mousePosition.move(scrollbar->x(), scrollbar->y());
 237     return blink::Platform::current()->scrollbarBehavior()->shouldSnapBackToDragOrigin(mousePosition, trackRect(scrollbar), scrollbar->orientation() == HorizontalScrollbar);
 238 }
 239
 240 // Returns the size represented by track taking into account scrolling past
 241 // the end of the document.
 242 static float usedTotalSize(ScrollbarThemeClient* scrollbar)
 243 {
 244     float overhangAtStart = -scrollbar->currentPos();
 245     float overhangAtEnd = scrollbar->currentPos() + scrollbar->visibleSize() - scrollbar->totalSize();
 246     float overhang = std::max(0.0f, std::max(overhangAtStart, overhangAtEnd));
 247     return scrollbar->totalSize() + overhang;
 248 }
 249
 250 int ScrollbarTheme::thumbPosition(ScrollbarThemeClient* scrollbar)
 251 {
 252     if (scrollbar->enabled()) {
 253         float size = usedTotalSize(scrollbar) - scrollbar->visibleSize();
 254         // Avoid doing a floating point divide by zero and return 1 when usedTotalSize == visibleSize.
 255         if (!size)
 256             return 1;
 257         float pos = std::max(0.0f, scrollbar->currentPos()) * (trackLength(scrollbar) - thumbLength(scrollbar)) / size;
 258         return (pos < 1 && pos > 0) ? 1 : pos;
 259     }
 260     return 0;
 261 }
 262
 263 int ScrollbarTheme::thumbLength(ScrollbarThemeClient* scrollbar)
 264 {
 265     if (!scrollbar->enabled())
 266         return 0;
 267
 268     float overhang = 0;
 269     if (scrollbar->currentPos() < 0)
 270         overhang = -scrollbar->currentPos();
 271     else if (scrollbar->visibleSize() + scrollbar->currentPos() > scrollbar->totalSize())
 272         overhang = scrollbar->currentPos() + scrollbar->visibleSize() - scrollbar->totalSize();
 273     float proportion = (scrollbar->visibleSize() - overhang) / usedTotalSize(scrollbar);
 274     int trackLen = trackLength(scrollbar);
 275     int length = round(proportion * trackLen);
 276     length = std::max(length, minimumThumbLength(scrollbar));
 277     if (length > trackLen)
 278         length = 0; // Once the thumb is below the track length, it just goes away (to make more room for the track).
 279     return length;
 280 }
 281
 282 int ScrollbarTheme::trackPosition(ScrollbarThemeClient* scrollbar)
 283 {
 284     IntRect constrainedTrackRect = constrainTrackRectToTrackPieces(scrollbar, trackRect(scrollbar));
 285     return (scrollbar->orientation() == HorizontalScrollbar) ? constrainedTrackRect.x() - scrollbar->x() : constrainedTrackRect.y() - scrollbar->y();
 286 }
 287
 288 int ScrollbarTheme::trackLength(ScrollbarThemeClient* scrollbar)
 289 {
 290     IntRect constrainedTrackRect = constrainTrackRectToTrackPieces(scrollbar, trackRect(scrollbar));
 291     return (scrollbar->orientation() == HorizontalScrollbar) ? constrainedTrackRect.width() : constrainedTrackRect.height();
 292 }
 293
 294 IntRect ScrollbarTheme::thumbRect(ScrollbarThemeClient* scrollbar)
 295 {
 296     if (!hasThumb(scrollbar))
 297         return IntRect();
 298
 299     IntRect track = trackRect(scrollbar);
 300     IntRect startTrackRect;
 301     IntRect thumbRect;
 302     IntRect endTrackRect;
 303     splitTrack(scrollbar, track, startTrackRect, thumbRect, endTrackRect);
 304
 305     return thumbRect;
 306 }
 307
 308 int ScrollbarTheme::thumbThickness(ScrollbarThemeClient* scrollbar)
 309 {
 310     IntRect track = trackRect(scrollbar);
 311     return scrollbar->orientation() == HorizontalScrollbar ? track.height() : track.width();
 312 }
 313
 314 int ScrollbarTheme::minimumThumbLength(ScrollbarThemeClient* scrollbar)
 315 {
 316     return scrollbarThickness(scrollbar->controlSize());
 317 }
 318
 319 void ScrollbarTheme::splitTrack(ScrollbarThemeClient* scrollbar, const IntRect& unconstrainedTrackRect, IntRect& beforeThumbRect, IntRect& thumbRect, IntRect& afterThumbRect)
 320 {
 321     // This function won't even get called unless we're big enough to have some combination of these three rects where at least
 322     // one of them is non-empty.
 323     IntRect trackRect = constrainTrackRectToTrackPieces(scrollbar, unconstrainedTrackRect);
 324     int thumbPos = thumbPosition(scrollbar);
 325     if (scrollbar->orientation() == HorizontalScrollbar) {
 326         thumbRect = IntRect(trackRect.x() + thumbPos, trackRect.y(), thumbLength(scrollbar), scrollbar->height());
 327         beforeThumbRect = IntRect(trackRect.x(), trackRect.y(), thumbPos + thumbRect.width() / 2, trackRect.height());
 328         afterThumbRect = IntRect(trackRect.x() + beforeThumbRect.width(), trackRect.y(), trackRect.maxX() - beforeThumbRect.maxX(), trackRect.height());
 329     } else {
 330         thumbRect = IntRect(trackRect.x(), trackRect.y() + thumbPos, scrollbar->width(), thumbLength(scrollbar));
 331         beforeThumbRect = IntRect(trackRect.x(), trackRect.y(), trackRect.width(), thumbPos + thumbRect.height() / 2);
 332         afterThumbRect = IntRect(trackRect.x(), trackRect.y() + beforeThumbRect.height(), trackRect.width(), trackRect.maxY() - beforeThumbRect.maxY());
 333     }
 334 }
 335
 336 ScrollbarTheme* ScrollbarTheme::theme()
 337 {
 338     if (ScrollbarTheme::mockScrollbarsEnabled()) {
 339         if (RuntimeEnabledFeatures::overlayScrollbarsEnabled()) {
 340             DEFINE_STATIC_LOCAL(ScrollbarThemeOverlayMock, overlayMockTheme, ());
 341             return &overlayMockTheme;
 342         }
 343
 344         DEFINE_STATIC_LOCAL(ScrollbarThemeMock, mockTheme, ());
 345         return &mockTheme;
 346     }
 347     return nativeTheme();
 348 }
 349
 350 void ScrollbarTheme::setMockScrollbarsEnabled(bool flag)
 351 {
 352     gMockScrollbarsEnabled = flag;
 353 }
 354
 355 bool ScrollbarTheme::mockScrollbarsEnabled()
 356 {
 357     return gMockScrollbarsEnabled;
 358 }
 359
 360 }