Pixel snap SVG's root border box to local transform [spv2]

third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp

 // Copyright 2015 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 "core/paint/PaintPropertyTreeBuilder.h"
 
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/layout/LayoutInline.h"
 #include "core/layout/LayoutPart.h"
 #include "core/layout/svg/LayoutSVGRoot.h"
 #include "core/paint/ObjectPaintProperties.h"
 #include "core/paint/PaintLayer.h"
+#include "core/paint/SVGRootPainter.h"
 #include "platform/transforms/TransformationMatrix.h"
 #include "wtf/PtrUtil.h"
 #include <memory>
 
 namespace blink {
 
 void PaintPropertyTreeBuilder::buildTreeRootNodes(FrameView& rootFrame, PaintPropertyTreeBuilderContext& context)
 {
     // Only create extra root clip and transform nodes when RLS is enabled, because the main frame
     // unconditionally create frame translation / clip nodes otherwise.
@@ skipping 229 matching lines @@
         context.currentTransform);
     context.currentTransform = perspective.get();
     object.getMutableForPainting().ensureObjectPaintProperties().setPerspective(perspective.release());
 }
 
 void PaintPropertyTreeBuilder::updateSvgLocalToBorderBoxTransform(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (!object.isSVGRoot())
         return;
 
-    AffineTransform transform = AffineTransform::translation(context.paintOffset.x().toFloat(), context.paintOffset.y().toFloat());
-    transform *= toLayoutSVGRoot(object).localToBorderBoxTransform();
-    if (transform.isIdentity())
+    AffineTransform snappedPaintOffsetToBorderBox = SVGRootPainter(toLayoutSVGRoot(object)).snappedPaintOffsetToBorderBox(context.paintOffset);
+    if (snappedPaintOffsetToBorderBox.isIdentity())
         return;
 
     RefPtr<TransformPaintPropertyNode> svgLocalToBorderBoxTransform = TransformPaintPropertyNode::create(
-        transform, FloatPoint3D(0, 0, 0), context.currentTransform);
+        snappedPaintOffsetToBorderBox, FloatPoint3D(0, 0, 0), context.currentTransform);
     context.currentTransform = svgLocalToBorderBoxTransform.get();
     context.paintOffset = LayoutPoint();
     object.getMutableForPainting().ensureObjectPaintProperties().setSvgLocalToBorderBoxTransform(svgLocalToBorderBoxTransform.release());
 }
 
 void PaintPropertyTreeBuilder::updateScrollTranslation(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (!object.isBoxModelObject() || !object.hasOverflowClip())
         return;
 
@@ skipping 122 matching lines @@
     updateOverflowClip(object, context);
     // TODO(trchen): Insert flattening transform here, as specified by
     // http://www.w3.org/TR/css3-transforms/#transform-style-property
     updatePerspective(object, context);
     updateSvgLocalToBorderBoxTransform(object, context);
     updateScrollTranslation(object, context);
     updateOutOfFlowContext(object, context);
 }
 
 } // namespace blink