Fix painting of fixed background images in composited layers

Source/core/rendering/RenderBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 1227 matching lines @@
         paintRootBoxFillLayers(paintInfo);
         return;
     }
     if (isBody() && skipBodyBackground(this))
         return;
     if (backgroundIsKnownToBeObscured())
         return;
     paintFillLayers(paintInfo, resolveColor(CSSPropertyBackgroundColor), style()->backgroundLayers(), paintRect, bleedAvoidance);
 }
 
-LayoutRect RenderBox::backgroundPaintedExtent() const
+bool RenderBox::getBackgroundPaintedExtent(LayoutRect& paintedExtent) const
 {
     ASSERT(hasBackground());
     LayoutRect backgroundRect = pixelSnappedIntRect(borderBoxRect());
 
     Color backgroundColor = resolveColor(CSSPropertyBackgroundColor);
-    if (backgroundColor.alpha())
-        return backgroundRect;
-    if (!style()->backgroundLayers()->image() || style()->backgroundLayers()->next())
-        return backgroundRect;
+    if (backgroundColor.alpha()) {
+        paintedExtent = backgroundRect;
+        return true;
+    }
+
+    if (!style()->backgroundLayers()->image() || style()->backgroundLayers()->next()) {
+        paintedExtent =  backgroundRect;
+        return true;
+    }
+
     BackgroundImageGeometry geometry;
-    const_cast<RenderBox*>(this)->calculateBackgroundImageGeometry(style()->backgroundLayers(), backgroundRect, geometry);
-    return geometry.destRect();
+    calculateBackgroundImageGeometry(0, style()->backgroundLayers(), backgroundRect, geometry);
+    if (geometry.hasNonLocalGeometry())
+        return false;
+    paintedExtent = geometry.destRect();
+    return true;
 }
 
 bool RenderBox::backgroundIsKnownToBeOpaqueInRect(const LayoutRect& localRect) const
 {
     if (isBody() && skipBodyBackground(this))
         return false;
 
     Color backgroundColor = resolveColor(CSSPropertyBackgroundColor);
     if (backgroundColor.hasAlpha())
         return false;
@@ skipping 89 matching lines @@
     // Test to see if the children trivially obscure the background.
     // FIXME: This test can be much more comprehensive.
     if (!hasBackground())
         return false;
     // Table and root background painting is special.
     if (isTable() || isRoot())
         return false;
     // FIXME: box-shadow is painted while background painting.
     if (style()->boxShadow())
         return false;
-    LayoutRect backgroundRect = backgroundPaintedExtent();
+    LayoutRect backgroundRect;
+    if (!getBackgroundPaintedExtent(backgroundRect))
+        return false;
     return foregroundIsKnownToBeOpaqueInRect(backgroundRect, backgroundObscurationTestMaxDepth);
 }
 
 bool RenderBox::backgroundHasOpaqueTopLayer() const
 {
     const FillLayer* fillLayer = style()->backgroundLayers();
     if (!fillLayer || fillLayer->clip() != BorderFillBox)
         return false;
 
     // Clipped with local scrolling
@@ skipping 83 matching lines @@
         // Apply outsets to the border box.
         borderImageRect.expand(style()->maskBoxImageOutsets());
         return borderImageRect;
     }
 
     LayoutRect result;
     LayoutRect borderBox = borderBoxRect();
     for (const FillLayer* maskLayer = style()->maskLayers(); maskLayer; maskLayer = maskLayer->next()) {
         if (maskLayer->image()) {
             BackgroundImageGeometry geometry;
-            calculateBackgroundImageGeometry(maskLayer, borderBox, geometry);
+            // Masks should never have fixed attachment, so it's OK for paintContainer to be null.
+            calculateBackgroundImageGeometry(0, maskLayer, borderBox, geometry);
             result.unite(geometry.destRect());
         }
     }
     return result;
 }
 
 void RenderBox::paintFillLayers(const PaintInfo& paintInfo, const Color& c, const FillLayer* fillLayer, const LayoutRect& rect,
     BackgroundBleedAvoidance bleedAvoidance, CompositeOperator op, RenderObject* backgroundObject)
 {
     Vector<const FillLayer*, 8> layers;
@@ skipping 75 matching lines @@
         layer()->contentChanged(MaskImageChanged);
 }
 
 bool RenderBox::repaintLayerRectsForImage(WrappedImagePtr image, const FillLayer* layers, bool drawingBackground)
 {
     LayoutRect rendererRect;
     RenderBox* layerRenderer = 0;
 
     for (const FillLayer* curLayer = layers; curLayer; curLayer = curLayer->next()) {
         if (curLayer->image() && image == curLayer->image()->data() && curLayer->image()->canRender(this, style()->effectiveZoom())) {
-            // Now that we know this image is being used, compute the renderer and the rect
-            // if we haven't already
+            // Now that we know this image is being used, compute the renderer and the rect if we haven't already.
             if (!layerRenderer) {
                 bool drawingRootBackground = drawingBackground && (isRoot() || (isBody() && !document().documentElement()->renderer()->hasBackground()));
                 if (drawingRootBackground) {
                     layerRenderer = view();
 
                     LayoutUnit rw;
                     LayoutUnit rh;
 
                     if (FrameView* frameView = toRenderView(layerRenderer)->frameView()) {
                         rw = frameView->contentsWidth();
                         rh = frameView->contentsHeight();
                     } else {
                         rw = layerRenderer->width();
                         rh = layerRenderer->height();
                     }
                     rendererRect = LayoutRect(-layerRenderer->marginLeft(),
                         -layerRenderer->marginTop(),
                         max(layerRenderer->width() + layerRenderer->marginWidth() + layerRenderer->borderLeft() + layerRenderer->borderRight(), rw),
                         max(layerRenderer->height() + layerRenderer->marginHeight() + layerRenderer->borderTop() + layerRenderer->borderBottom(), rh));
                 } else {
                     layerRenderer = this;
                     rendererRect = borderBoxRect();
                 }
             }
 
             BackgroundImageGeometry geometry;
-            layerRenderer->calculateBackgroundImageGeometry(curLayer, rendererRect, geometry);
+            layerRenderer->calculateBackgroundImageGeometry(0, curLayer, rendererRect, geometry);
+            if (geometry.hasNonLocalGeometry()) {
+                // Rather than incur the costs of computing the paintContainer for renderers with fixed backgrounds
+                // in order to get the right destRect, just repaint the entire renderer.
+                layerRenderer->repaint();
+                return true;
+            }
+
             layerRenderer->repaintRectangle(geometry.destRect());
             if (geometry.destRect() == rendererRect)
                 return true;
         }
     }
     return false;
 }
 
 bool RenderBox::pushContentsClip(PaintInfo& paintInfo, const LayoutPoint& accumulatedOffset, ContentsClipBehavior contentsClipBehavior)
 {
@@ skipping 3054 matching lines @@
         return 0;
 
     if (!layoutState && !flowThreadContainingBlock())
         return 0;
 
     RenderBlock* containerBlock = containingBlock();
     return containerBlock->offsetFromLogicalTopOfFirstPage() + logicalTop();
 }
 
 } // namespace WebCore