Pass accurate contentsScale to LayerImpl.

cc/scrollbar_layer.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 
 #include "cc/scrollbar_layer.h"
 
 #include "base/basictypes.h"
 #include "base/debug/trace_event.h"
@@ skipping 25 matching lines @@
     , m_textureFormat(GL_INVALID_ENUM)
 {
 }
 
 ScrollbarLayer::~ScrollbarLayer()
 {
 }
 
 void ScrollbarLayer::pushPropertiesTo(LayerImpl* layer)
 {
-    Layer::pushPropertiesTo(layer);
+    ContentsScalingLayer::pushPropertiesTo(layer);
 
     ScrollbarLayerImpl* scrollbarLayer = static_cast<ScrollbarLayerImpl*>(layer);
 
     if (!scrollbarLayer->scrollbarGeometry())
         scrollbarLayer->setScrollbarGeometry(ScrollbarGeometryFixedThumb::create(make_scoped_ptr(m_geometry->clone())));
 
     scrollbarLayer->setScrollbarData(m_scrollbar.get());
 
     if (m_backTrack && m_backTrack->texture()->haveBackingTexture())
         scrollbarLayer->setBackTrackResourceId(m_backTrack->texture()->resourceId());
@@ skipping 66 matching lines @@
     }
 
     WebKit::WebScrollbar* m_scrollbar;
     WebKit::WebScrollbarThemePainter m_painter;
     WebKit::WebScrollbarThemeGeometry* m_geometry;
     WebKit::WebScrollbar::ScrollbarPart m_trackPart;
 
     DISALLOW_COPY_AND_ASSIGN(ScrollbarBackgroundPainter);
 };
 
-bool ScrollbarLayer::needsContentsScale() const
-{
-    return true;
-}
-
-IntSize ScrollbarLayer::contentBounds() const
-{
-    return IntSize(lroundf(bounds().width() * contentsScale()), lroundf(bounds().height() * contentsScale()));
-}
-
 class ScrollbarThumbPainter : public LayerPainter {
 public:
     static scoped_ptr<ScrollbarThumbPainter> create(WebKit::WebScrollbar* scrollbar, WebKit::WebScrollbarThemePainter painter, WebKit::WebScrollbarThemeGeometry* geometry)
     {
         return make_scoped_ptr(new ScrollbarThumbPainter(scrollbar, painter, geometry));
     }
 
     virtual void paint(SkCanvas* skCanvas, const gfx::Rect& contentRect, gfx::RectF& opaque) OVERRIDE
     {
         WebKit::WebCanvas* canvas = skCanvas;
@@ skipping 22 matching lines @@
 
 void ScrollbarLayer::setLayerTreeHost(LayerTreeHost* host)
 {
     if (!host || host != layerTreeHost()) {
         m_backTrackUpdater = NULL;
         m_backTrack.reset();
         m_thumbUpdater = NULL;
         m_thumb.reset();
     }
 
-    Layer::setLayerTreeHost(host);
+    ContentsScalingLayer::setLayerTreeHost(host);
 }
 
 void ScrollbarLayer::createUpdaterIfNeeded()
 {
     m_textureFormat = layerTreeHost()->rendererCapabilities().bestTextureFormat;
 
     if (!m_backTrackUpdater)
         m_backTrackUpdater = CachingBitmapContentLayerUpdater::Create(ScrollbarBackgroundPainter::create(m_scrollbar.get(), m_painter, m_geometry.get(), WebKit::WebScrollbar::BackTrackPart).PassAs<LayerPainter>());
     if (!m_backTrack)
         m_backTrack = m_backTrackUpdater->createResource(layerTreeHost()->contentsTextureManager());
@@ skipping 20 matching lines @@
             && texture->texture()->size() == rect.size()
             && m_updateRect.isEmpty())
         return;
 
     // We should always have enough memory for UI.
     DCHECK(texture->texture()->canAcquireBackingTexture());
     if (!texture->texture()->canAcquireBackingTexture())
         return;
 
     // Paint and upload the entire part.
-    float widthScale = static_cast<float>(contentBounds().width()) / bounds().width();
-    float heightScale = static_cast<float>(contentBounds().height()) / bounds().height();
     gfx::Rect paintedOpaqueRect;
-    painter->prepareToUpdate(rect, rect.size(), widthScale, heightScale, paintedOpaqueRect, stats);
+    painter->prepareToUpdate(rect, rect.size(), contentsScaleX(), contentsScaleY(), paintedOpaqueRect, stats);
     if (!painter->pixelsDidChange() && texture->texture()->haveBackingTexture()) {
         TRACE_EVENT_INSTANT0("cc","ScrollbarLayer::updatePart no texture upload needed");
         return;
     }
 
     gfx::Vector2d destOffset(0, 0);
     texture->update(queue, rect, destOffset, false, stats);
 }
 
+IntRect ScrollbarLayer::scrollbarLayerRectToContentRect(const WebRect& layerRect) const
+{
+    // Don't intersect with the bounds as in layerRectToContentRect() because
+    // layerRect here might be in coordinates of the containing layer.
+    FloatRect contentRect(layerRect.x, layerRect.y, layerRect.width, layerRect.height);
+    contentRect.scale(contentsScaleX(), contentsScaleY());
+    return enclosingIntRect(contentRect);
+}
 
 void ScrollbarLayer::setTexturePriorities(const PriorityCalculator&)
 {
     if (contentBounds().isEmpty())
         return;
 
     createUpdaterIfNeeded();
 
     bool drawsToRoot = !renderTarget()->parent();
     if (m_backTrack) {
         m_backTrack->texture()->setDimensions(contentBounds(), m_textureFormat);
         m_backTrack->texture()->setRequestPriority(PriorityCalculator::uiPriority(drawsToRoot));
     }
     if (m_foreTrack) {
         m_foreTrack->texture()->setDimensions(contentBounds(), m_textureFormat);
         m_foreTrack->texture()->setRequestPriority(PriorityCalculator::uiPriority(drawsToRoot));
     }
     if (m_thumb) {
-        IntSize thumbSize = layerRectToContentRect(m_geometry->thumbRect(m_scrollbar.get())).size();
+        IntSize thumbSize = scrollbarLayerRectToContentRect(m_geometry->thumbRect(m_scrollbar.get())).size();
         m_thumb->texture()->setDimensions(thumbSize, m_textureFormat);
         m_thumb->texture()->setRequestPriority(PriorityCalculator::uiPriority(drawsToRoot));
     }
 }
 
 void ScrollbarLayer::update(ResourceUpdateQueue& queue, const OcclusionTracker*, RenderingStats& stats)
 {
     if (contentBounds().isEmpty())
         return;
 
     createUpdaterIfNeeded();
 
-    IntPoint scrollbarOrigin(m_scrollbar->location().x, m_scrollbar->location().y);
-    IntRect contentRect = layerRectToContentRect(WebKit::WebRect(scrollbarOrigin.x(), scrollbarOrigin.y(), bounds().width(), bounds().height()));
+    IntRect contentRect = scrollbarLayerRectToContentRect(WebRect(m_scrollbar->location().x, m_scrollbar->location().y, bounds().width(), bounds().height()));
     updatePart(m_backTrackUpdater.get(), m_backTrack.get(), contentRect, queue, stats);
     if (m_foreTrack && m_foreTrackUpdater)
         updatePart(m_foreTrackUpdater.get(), m_foreTrack.get(), contentRect, queue, stats);
 
     // Consider the thumb to be at the origin when painting.
     WebKit::WebRect thumbRect = m_geometry->thumbRect(m_scrollbar.get());
-    IntRect originThumbRect = layerRectToContentRect(WebKit::WebRect(0, 0, thumbRect.width, thumbRect.height));
+    IntRect originThumbRect = scrollbarLayerRectToContentRect(WebRect(0, 0, thumbRect.width, thumbRect.height));
     if (!originThumbRect.isEmpty())
         updatePart(m_thumbUpdater.get(), m_thumb.get(), originThumbRect, queue, stats);
 }
 
 }