Source/WebCore/platform/ScrollbarThemeComposite.cpp

   1 /*
   2  * Copyright (C) 2008 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 "ScrollbarThemeComposite.h"
  28
  29 #include "Chrome.h"
  30 #include "ChromeClient.h"
  31 #include "Frame.h"
  32 #include "FrameView.h"
  33 #include "GraphicsContext.h"
  34 #include "Page.h"
  35 #include "PlatformMouseEvent.h"
  36 #include "Scrollbar.h"
  37 #include "ScrollableArea.h"
  38 #include "Settings.h"
  39
  40 using namespace std;
  41
  42 namespace WebCore {
  43
  44 bool ScrollbarThemeComposite::paint(Scrollbar* scrollbar, GraphicsContext* graphicsContext, const IntRect& damageRect)
  45 {
  46     // Create the ScrollbarControlPartMask based on the damageRect
  47     ScrollbarControlPartMask scrollMask = NoPart;
  48
  49     IntRect backButtonStartPaintRect;
  50     IntRect backButtonEndPaintRect;
  51     IntRect forwardButtonStartPaintRect;
  52     IntRect forwardButtonEndPaintRect;
  53     if (hasButtons(scrollbar)) {
  54         backButtonStartPaintRect = backButtonRect(scrollbar, BackButtonStartPart, true);
  55         if (damageRect.intersects(backButtonStartPaintRect))
  56             scrollMask |= BackButtonStartPart;
  57         backButtonEndPaintRect = backButtonRect(scrollbar, BackButtonEndPart, true);
  58         if (damageRect.intersects(backButtonEndPaintRect))
  59             scrollMask |= BackButtonEndPart;
  60         forwardButtonStartPaintRect = forwardButtonRect(scrollbar, ForwardButtonStartPart, true);
  61         if (damageRect.intersects(forwardButtonStartPaintRect))
  62             scrollMask |= ForwardButtonStartPart;
  63         forwardButtonEndPaintRect = forwardButtonRect(scrollbar, ForwardButtonEndPart, true);
  64         if (damageRect.intersects(forwardButtonEndPaintRect))
  65             scrollMask |= ForwardButtonEndPart;
  66     }
  67
  68     IntRect startTrackRect;
  69     IntRect thumbRect;
  70     IntRect endTrackRect;
  71     IntRect trackPaintRect = trackRect(scrollbar, true);
  72     if (damageRect.intersects(trackPaintRect))
  73         scrollMask |= TrackBGPart;
  74     bool thumbPresent = hasThumb(scrollbar);
  75     if (thumbPresent) {
  76         IntRect track = trackRect(scrollbar);
  77         splitTrack(scrollbar, track, startTrackRect, thumbRect, endTrackRect);
  78         if (damageRect.intersects(thumbRect))
  79             scrollMask |= ThumbPart;
  80         if (damageRect.intersects(startTrackRect))
  81             scrollMask |= BackTrackPart;
  82         if (damageRect.intersects(endTrackRect))
  83             scrollMask |= ForwardTrackPart;
  84     }
  85
  86     // Paint the scrollbar background (only used by custom CSS scrollbars).
  87     paintScrollbarBackground(graphicsContext, scrollbar);
  88
  89     // Paint the back and forward buttons.
  90     if (scrollMask & BackButtonStartPart)
  91         paintButton(graphicsContext, scrollbar, backButtonStartPaintRect, BackButtonStartPart);
  92     if (scrollMask & BackButtonEndPart)
  93         paintButton(graphicsContext, scrollbar, backButtonEndPaintRect, BackButtonEndPart);
  94     if (scrollMask & ForwardButtonStartPart)
  95         paintButton(graphicsContext, scrollbar, forwardButtonStartPaintRect, ForwardButtonStartPart);
  96     if (scrollMask & ForwardButtonEndPart)
  97         paintButton(graphicsContext, scrollbar, forwardButtonEndPaintRect, ForwardButtonEndPart);
  98
  99     if (scrollMask & TrackBGPart)
 100         paintTrackBackground(graphicsContext, scrollbar, trackPaintRect);
 101
 102     if ((scrollMask & ForwardTrackPart) || (scrollMask & BackTrackPart)) {
 103         // Paint the track pieces above and below the thumb.
 104         if (scrollMask & BackTrackPart)
 105             paintTrackPiece(graphicsContext, scrollbar, startTrackRect, BackTrackPart);
 106         if (scrollMask & ForwardTrackPart)
 107             paintTrackPiece(graphicsContext, scrollbar, endTrackRect, ForwardTrackPart);
 108
 109         paintTickmarks(graphicsContext, scrollbar, trackPaintRect);
 110     }
 111
 112     // Paint the thumb.
 113     if (scrollMask & ThumbPart)
 114         paintThumb(graphicsContext, scrollbar, thumbRect);
 115
 116     return true;
 117 }
 118
 119 ScrollbarPart ScrollbarThemeComposite::hitTest(Scrollbar* scrollbar, const PlatformMouseEvent& evt)
 120 {
 121     ScrollbarPart result = NoPart;
 122     if (!scrollbar->enabled())
 123         return result;
 124
 125     IntPoint mousePosition = scrollbar->convertFromContainingWindow(evt.pos());
 126     mousePosition.move(scrollbar->x(), scrollbar->y());
 127
 128     if (!scrollbar->frameRect().contains(mousePosition))
 129         return NoPart;
 130
 131     result = ScrollbarBGPart;
 132
 133     IntRect track = trackRect(scrollbar);
 134     if (track.contains(mousePosition)) {
 135         IntRect beforeThumbRect;
 136         IntRect thumbRect;
 137         IntRect afterThumbRect;
 138         splitTrack(scrollbar, track, beforeThumbRect, thumbRect, afterThumbRect);
 139         if (thumbRect.contains(mousePosition))
 140             result = ThumbPart;
 141         else if (beforeThumbRect.contains(mousePosition))
 142             result = BackTrackPart;
 143         else if (afterThumbRect.contains(mousePosition))
 144             result = ForwardTrackPart;
 145         else
 146             result = TrackBGPart;
 147     } else if (backButtonRect(scrollbar, BackButtonStartPart).contains(mousePosition))
 148         result = BackButtonStartPart;
 149     else if (backButtonRect(scrollbar, BackButtonEndPart).contains(mousePosition))
 150         result = BackButtonEndPart;
 151     else if (forwardButtonRect(scrollbar, ForwardButtonStartPart).contains(mousePosition))
 152         result = ForwardButtonStartPart;
 153     else if (forwardButtonRect(scrollbar, ForwardButtonEndPart).contains(mousePosition))
 154         result = ForwardButtonEndPart;
 155     return result;
 156 }
 157
 158 void ScrollbarThemeComposite::invalidatePart(Scrollbar* scrollbar, ScrollbarPart part)
 159 {
 160     if (part == NoPart)
 161         return;
 162
 163     IntRect result;
 164     switch (part) {
 165         case BackButtonStartPart:
 166             result = backButtonRect(scrollbar, BackButtonStartPart, true);
 167             break;
 168         case BackButtonEndPart:
 169             result = backButtonRect(scrollbar, BackButtonEndPart, true);
 170             break;
 171         case ForwardButtonStartPart:
 172             result = forwardButtonRect(scrollbar, ForwardButtonStartPart, true);
 173             break;
 174         case ForwardButtonEndPart:
 175             result = forwardButtonRect(scrollbar, ForwardButtonEndPart, true);
 176             break;
 177         case TrackBGPart:
 178             result = trackRect(scrollbar, true);
 179             break;
 180         case ScrollbarBGPart:
 181             result = scrollbar->frameRect();
 182             break;
 183         default: {
 184             IntRect beforeThumbRect, thumbRect, afterThumbRect;
 185             splitTrack(scrollbar, trackRect(scrollbar), beforeThumbRect, thumbRect, afterThumbRect);
 186             if (part == BackTrackPart)
 187                 result = beforeThumbRect;
 188             else if (part == ForwardTrackPart)
 189                 result = afterThumbRect;
 190             else
 191                 result = thumbRect;
 192         }
 193     }
 194     result.moveBy(-scrollbar->location());
 195     scrollbar->invalidateRect(result);
 196 }
 197
 198 void ScrollbarThemeComposite::splitTrack(Scrollbar* scrollbar, const IntRect& unconstrainedTrackRect, IntRect& beforeThumbRect, IntRect& thumbRect, IntRect& afterThumbRect)
 199 {
 200     // This function won't even get called unless we're big enough to have some combination of these three rects where at least
 201     // one of them is non-empty.
 202     IntRect trackRect = constrainTrackRectToTrackPieces(scrollbar, unconstrainedTrackRect);
 203     int thickness = scrollbar->orientation() == HorizontalScrollbar ? scrollbar->height() : scrollbar->width();
 204     int thumbPos = thumbPosition(scrollbar);
 205     if (scrollbar->orientation() == HorizontalScrollbar) {
 206         thumbRect = IntRect(trackRect.x() + thumbPos, trackRect.y() + (trackRect.height() - thickness) / 2, thumbLength(scrollbar), thickness);
 207         beforeThumbRect = IntRect(trackRect.x(), trackRect.y(), thumbPos + thumbRect.width() / 2, trackRect.height());
 208         afterThumbRect = IntRect(trackRect.x() + beforeThumbRect.width(), trackRect.y(), trackRect.maxX() - beforeThumbRect.maxX(), trackRect.height());
 209     } else {
 210         thumbRect = IntRect(trackRect.x() + (trackRect.width() - thickness) / 2, trackRect.y() + thumbPos, thickness, thumbLength(scrollbar));
 211         beforeThumbRect = IntRect(trackRect.x(), trackRect.y(), trackRect.width(), thumbPos + thumbRect.height() / 2);
 212         afterThumbRect = IntRect(trackRect.x(), trackRect.y() + beforeThumbRect.height(), trackRect.width(), trackRect.maxY() - beforeThumbRect.maxY());
 213     }
 214 }
 215
 216 // Returns the size represented by track taking into account scrolling past
 217 // the end of the document.
 218 static float usedTotalSize(Scrollbar* scrollbar)
 219 {
 220     float overhangAtStart = -scrollbar->currentPos();
 221     float overhangAtEnd = scrollbar->currentPos() + scrollbar->visibleSize() - scrollbar->totalSize();
 222     float overhang = max(0.0f, max(overhangAtStart, overhangAtEnd));
 223     return scrollbar->totalSize() + overhang;
 224 }
 225
 226 int ScrollbarThemeComposite::thumbPosition(Scrollbar* scrollbar)
 227 {
 228     if (scrollbar->enabled()) {
 229         float pos = max(0.0f, scrollbar->currentPos()) * (trackLength(scrollbar) - thumbLength(scrollbar)) / (usedTotalSize(scrollbar) - scrollbar->visibleSize());
 230         return (pos < 1 && pos > 0) ? 1 : pos;
 231     }
 232     return 0;
 233 }
 234
 235 int ScrollbarThemeComposite::thumbLength(Scrollbar* scrollbar)
 236 {
 237     if (!scrollbar->enabled())
 238         return 0;
 239
 240     float proportion = scrollbar->visibleSize() / usedTotalSize(scrollbar);
 241     int trackLen = trackLength(scrollbar);
 242     int length = proportion * trackLen;
 243     length = max(length, minimumThumbLength(scrollbar));
 244     if (length > trackLen)
 245         length = 0; // Once the thumb is below the track length, it just goes away (to make more room for the track).
 246     return length;
 247 }
 248
 249 int ScrollbarThemeComposite::minimumThumbLength(Scrollbar* scrollbar)
 250 {
 251     return scrollbarThickness(scrollbar->controlSize());
 252 }
 253
 254 int ScrollbarThemeComposite::trackPosition(Scrollbar* scrollbar)
 255 {
 256     IntRect constrainedTrackRect = constrainTrackRectToTrackPieces(scrollbar, trackRect(scrollbar));
 257     return (scrollbar->orientation() == HorizontalScrollbar) ? constrainedTrackRect.x() - scrollbar->x() : constrainedTrackRect.y() - scrollbar->y();
 258 }
 259
 260 int ScrollbarThemeComposite::trackLength(Scrollbar* scrollbar)
 261 {
 262     IntRect constrainedTrackRect = constrainTrackRectToTrackPieces(scrollbar, trackRect(scrollbar));
 263     return (scrollbar->orientation() == HorizontalScrollbar) ? constrainedTrackRect.width() : constrainedTrackRect.height();
 264 }
 265
 266 void ScrollbarThemeComposite::paintScrollCorner(ScrollView*, GraphicsContext* context, const IntRect& cornerRect)
 267 {
 268     context->fillRect(cornerRect, Color::white, ColorSpaceDeviceRGB);
 269 }
 270
 271 void ScrollbarThemeComposite::paintOverhangAreas(ScrollView*, GraphicsContext* context, const IntRect& horizontalOverhangRect, const IntRect& verticalOverhangRect, const IntRect& dirtyRect)
 272 {
 273     context->setFillColor(Color::white, ColorSpaceDeviceRGB);
 274     if (!horizontalOverhangRect.isEmpty())
 275         context->fillRect(intersection(horizontalOverhangRect, dirtyRect));
 276
 277     context->setFillColor(Color::white, ColorSpaceDeviceRGB);
 278     if (!verticalOverhangRect.isEmpty())
 279         context->fillRect(intersection(verticalOverhangRect, dirtyRect));
 280 }
 281
 282 }