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      1 // Copyright 2014 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "config.h"
      6 #include "core/rendering/PaintInvalidationState.h"
      7 
      8 #include "core/rendering/RenderInline.h"
      9 #include "core/rendering/RenderLayer.h"
     10 #include "core/rendering/RenderView.h"
     11 #include "core/rendering/svg/RenderSVGModelObject.h"
     12 #include "platform/Partitions.h"
     13 
     14 namespace blink {
     15 
     16 PaintInvalidationState::PaintInvalidationState(const RenderView& renderView)
     17     : m_clipped(false)
     18     , m_cachedOffsetsEnabled(true)
     19     , m_forceCheckForPaintInvalidation(false)
     20     , m_paintInvalidationContainer(*renderView.containerForPaintInvalidation())
     21 {
     22     bool establishesPaintInvalidationContainer = renderView == m_paintInvalidationContainer;
     23     if (!establishesPaintInvalidationContainer) {
     24         if (!renderView.supportsPaintInvalidationStateCachedOffsets()) {
     25             m_cachedOffsetsEnabled = false;
     26             return;
     27         }
     28         FloatPoint point = renderView.localToContainerPoint(FloatPoint(), &m_paintInvalidationContainer, TraverseDocumentBoundaries);
     29         m_paintOffset = LayoutSize(point.x(), point.y());
     30     }
     31     m_clipRect = renderView.viewRect();
     32     m_clipRect.move(m_paintOffset);
     33     m_clipped = true;
     34 }
     35 
     36 PaintInvalidationState::PaintInvalidationState(const PaintInvalidationState& next, RenderLayerModelObject& renderer, const RenderLayerModelObject& paintInvalidationContainer)
     37     : m_clipped(false)
     38     , m_cachedOffsetsEnabled(true)
     39     , m_forceCheckForPaintInvalidation(next.m_forceCheckForPaintInvalidation)
     40     , m_paintInvalidationContainer(paintInvalidationContainer)
     41 {
     42     // FIXME: SVG could probably benefit from a stack-based optimization like html does. crbug.com/391054
     43     bool establishesPaintInvalidationContainer = renderer == m_paintInvalidationContainer;
     44     bool fixed = renderer.style()->position() == FixedPosition;
     45 
     46     if (establishesPaintInvalidationContainer) {
     47         // When we hit a new paint invalidation container, we don't need to
     48         // continue forcing a check for paint invalidation because movement
     49         // from our parents will just move the whole invalidation container.
     50         m_forceCheckForPaintInvalidation = false;
     51     } else {
     52         if (!renderer.supportsPaintInvalidationStateCachedOffsets() || !next.m_cachedOffsetsEnabled) {
     53             m_cachedOffsetsEnabled = false;
     54         } else {
     55             if (fixed) {
     56                 FloatPoint fixedOffset = renderer.localToContainerPoint(FloatPoint(), &m_paintInvalidationContainer, TraverseDocumentBoundaries);
     57                 m_paintOffset = LayoutSize(fixedOffset.x(), fixedOffset.y());
     58             } else {
     59                 LayoutSize offset = renderer.isBox() && !renderer.isTableRow() ? toRenderBox(renderer).locationOffset() : LayoutSize();
     60                 m_paintOffset = next.m_paintOffset + offset;
     61             }
     62 
     63             if (renderer.isOutOfFlowPositioned() && !fixed) {
     64                 if (RenderObject* container = renderer.container()) {
     65                     if (container->style()->hasInFlowPosition() && container->isRenderInline())
     66                         m_paintOffset += toRenderInline(container)->offsetForInFlowPositionedInline(toRenderBox(renderer));
     67                 }
     68             }
     69 
     70             if (renderer.style()->hasInFlowPosition() && renderer.hasLayer())
     71                 m_paintOffset += renderer.layer()->offsetForInFlowPosition();
     72         }
     73 
     74         m_clipped = !fixed && next.m_clipped;
     75         if (m_clipped)
     76             m_clipRect = next.m_clipRect;
     77     }
     78 
     79     applyClipIfNeeded(renderer);
     80 
     81     // FIXME: <http://bugs.webkit.org/show_bug.cgi?id=13443> Apply control clip if present.
     82 }
     83 
     84 void PaintInvalidationState::applyClipIfNeeded(const RenderObject& renderer)
     85 {
     86     if (!renderer.hasOverflowClip())
     87         return;
     88 
     89     const RenderBox& box = toRenderBox(renderer);
     90 
     91     // Do not clip scroll layer contents because the compositor expects the whole layer
     92     // to be always invalidated in-time.
     93     if (box.usesCompositedScrolling()) {
     94         ASSERT(!m_clipped); // The box should establish paint invalidation container, so no m_clipped inherited.
     95     } else {
     96         LayoutRect clipRect(toPoint(m_paintOffset), box.layer()->size());
     97         if (m_clipped) {
     98             m_clipRect.intersect(clipRect);
     99         } else {
    100             m_clipRect = clipRect;
    101             m_clipped = true;
    102         }
    103     }
    104 
    105     m_paintOffset -= box.scrolledContentOffset();
    106 }
    107 
    108 } // namespace blink
    109