Move all fast-path paint invalidation mapping into PaintInvalidationState

third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.cpp

 /*
  * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2007, 2008, 2009 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Google, Inc.
  * Copyright (C) Research In Motion Limited 2011. 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
  * License as published by the Free Software Foundation; either
@@ skipping 300 matching lines @@
 {
     // Slightly optimized version of m_localToParentTransform = AffineTransform::translation(x(), y()) * m_localToBorderBoxTransform;
     m_localToParentTransform = m_localToBorderBoxTransform;
     if (location().x())
         m_localToParentTransform.setE(m_localToParentTransform.e() + roundToInt(location().x()));
     if (location().y())
         m_localToParentTransform.setF(m_localToParentTransform.f() + roundToInt(location().y()));
     return m_localToParentTransform;
 }
 
-LayoutRect LayoutSVGRoot::clippedOverflowRectForPaintInvalidation(const LayoutBoxModelObject* paintInvalidationContainer, const PaintInvalidationState* paintInvalidationState) const
+LayoutRect LayoutSVGRoot::localOverflowRectForPaintInvalidation() const
 {
-    // This is an open-coded aggregate of SVGLayoutSupport::clippedOverflowRectForPaintInvalidation,
-    // LayoutSVGRoot::mapToVisibleRectInAncestorSpace and LayoutReplaced::clippedOverflowRectForPaintInvalidation.
+    // This is an open-coded aggregate of SVGLayoutSupport::localOverflowRectForPaintInvalidation,

[pdr., 2016/03/25 01:08:01]

This comment is no longer correct because mapToVisibleRectInAncestorSpace is not
called at the end.

Is this optimization needed anymore?

[Xianzhu, 2016/03/25 16:35:54]

Removed LayoutSVGRoot::mapToVisibleRectInAncestorSpace from the comment.

Added a TODO here for verifying the optimization. Don't want to expand the CL
any more :)

+    // LayoutSVGRoot::mapToVisibleRectInAncestorSpace and LayoutReplaced::localOverflowRectForPaintInvalidation.
     // The reason for this is to optimize/minimize the paint invalidation rect when the box is not "decorated"
     // (does not have background/border/etc.)
 
     // Return early for any cases where we don't actually paint.
     if (style()->visibility() != VISIBLE && !enclosingLayer()->hasVisibleContent())
         return LayoutRect();
 
     // Compute the paint invalidation rect of the content of the SVG in the border-box coordinate space.
     FloatRect contentPaintInvalidationRect = paintInvalidationRectInLocalSVGCoordinates();
     contentPaintInvalidationRect = m_localToBorderBoxTransform.mapRect(contentPaintInvalidationRect);
 
     // Apply initial viewport clip, overflow:visible content is added to visualOverflow
     // but the most common case is that overflow is hidden, so always intersect.
     contentPaintInvalidationRect.intersect(pixelSnappedBorderBoxRect());

[pdr., 2016/03/25 01:08:01]

It seems wrong that this is missing the shouldApplyViewportClip check from
mapToVisibleRectInAncestorSpace. Do you agree? If so, can you add a TODO to
investigate it?

[Xianzhu, 2016/03/25 16:35:55]

Actually the shouldApplyViewportClip is wrong in
LayoutSVGRoot::mapToVisibleRectInAncestorSpace() because it applies to contents
only. The clip should be done by children before passing a rect in its space to
LayoutSVGRoot::mapToVisibleRectInAncestorSpace(). Similarly we should not apply
viewport clip here.

Filed crbug.com/597813.

 
     LayoutRect paintInvalidationRect = enclosingLayoutRect(contentPaintInvalidationRect);
     // If the box is decorated or is overflowing, extend it to include the border-box and overflow.
     if (m_hasBoxDecorationBackground || hasOverflowModel()) {
         // The selectionRect can project outside of the overflowRect, so take their union
         // for paint invalidation to avoid selection painting glitches.
         LayoutRect decoratedPaintInvalidationRect = unionRect(localSelectionRect(), visualOverflowRect());
         paintInvalidationRect.unite(decoratedPaintInvalidationRect);
     }
 
-    // Compute the paint invalidation rect in the parent coordinate space.
-    LayoutRect rect(enclosingIntRect(paintInvalidationRect));
-    LayoutReplaced::mapToVisibleRectInAncestorSpace(paintInvalidationContainer, rect, paintInvalidationState);
-    return rect;
+    return LayoutRect(enclosingIntRect(paintInvalidationRect));
 }
 
-void LayoutSVGRoot::mapToVisibleRectInAncestorSpace(const LayoutBoxModelObject* ancestor, LayoutRect& rect, const PaintInvalidationState* paintInvalidationState) const
+void LayoutSVGRoot::mapToVisibleRectInAncestorSpace(const LayoutBoxModelObject* ancestor, LayoutRect& rect) const
 {
     // Note that we don't apply the border-box transform here - it's assumed
     // that whoever called us has done that already.
 
     // Apply initial viewport clip
     if (shouldApplyViewportClip())
         rect.intersect(LayoutRect(pixelSnappedBorderBoxRect()));
 
-    LayoutReplaced::mapToVisibleRectInAncestorSpace(ancestor, rect, paintInvalidationState);
+    LayoutReplaced::mapToVisibleRectInAncestorSpace(ancestor, rect);
 }
 
 // This method expects local CSS box coordinates.
 // Callers with local SVG viewport coordinates should first apply the localToBorderBoxTransform
 // to convert from SVG viewport coordinates to local CSS box coordinates.
-void LayoutSVGRoot::mapLocalToAncestor(const LayoutBoxModelObject* ancestor, TransformState& transformState, MapCoordinatesFlags mode, bool* wasFixed, const PaintInvalidationState* paintInvalidationState) const
+void LayoutSVGRoot::mapLocalToAncestor(const LayoutBoxModelObject* ancestor, TransformState& transformState, MapCoordinatesFlags mode, bool* wasFixed) const
 {
     ASSERT(!(mode & IsFixed)); // We should have no fixed content in the SVG layout tree.
 
-    LayoutReplaced::mapLocalToAncestor(ancestor, transformState, mode | ApplyContainerFlip, wasFixed, paintInvalidationState);
+    LayoutReplaced::mapLocalToAncestor(ancestor, transformState, mode | ApplyContainerFlip, wasFixed);
 }
 
 const LayoutObject* LayoutSVGRoot::pushMappingToContainer(const LayoutBoxModelObject* ancestorToStopAt, LayoutGeometryMap& geometryMap) const
 {
     return LayoutReplaced::pushMappingToContainer(ancestorToStopAt, geometryMap);
 }
 
 void LayoutSVGRoot::updateCachedBoundaries()
 {
     SVGLayoutSupport::computeContainerBoundingBoxes(this, m_objectBoundingBox, m_objectBoundingBoxValid, m_strokeBoundingBox, m_paintInvalidationBoundingBox);
@@ skipping 35 matching lines @@
             updateHitTestResult(result, pointInBorderBox);
             if (result.addNodeToListBasedTestResult(node(), locationInContainer, boundsRect) == StopHitTesting)
                 return true;
         }
     }
 
     return false;
 }
 
 } // namespace blink