[SVG] Compensate for container size snapping

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

 // Copyright 2014 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/SVGRootPainter.h"
 
 #include "core/layout/svg/LayoutSVGRoot.h"
 #include "core/layout/svg/SVGResources.h"
 #include "core/layout/svg/SVGResourcesCache.h"
 #include "core/paint/BoxPainter.h"
 #include "core/paint/ObjectPaintProperties.h"
 #include "core/paint/PaintInfo.h"
 #include "core/paint/PaintTiming.h"
 #include "core/paint/SVGPaintContext.h"
 #include "core/paint/TransformRecorder.h"
 #include "core/svg/SVGSVGElement.h"
 #include "platform/graphics/paint/ClipRecorder.h"
 #include "platform/graphics/paint/ScopedPaintChunkProperties.h"
 #include "wtf/Optional.h"
 
 namespace blink {
 
 void SVGRootPainter::paint(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
+    // Pixel-snap to match BoxPainter's alignment.
+    const IntRect adjustedRect = pixelSnappedIntRect(paintOffset, m_layoutSVGRoot.size());
+
     // An empty viewport disables rendering.
-    if (m_layoutSVGRoot.pixelSnappedBorderBoxRect().isEmpty())
+    if (adjustedRect.isEmpty())
         return;
 
     // SVG outlines are painted during PaintPhaseForeground.
     if (shouldPaintSelfOutline(paintInfo.phase))
         return;
 
     // An empty viewBox also disables rendering.
     // (http://www.w3.org/TR/SVG/coords.html#ViewBoxAttribute)
     SVGSVGElement* svg = toSVGSVGElement(m_layoutSVGRoot.node());
     ASSERT(svg);
@@ skipping 26 matching lines @@
 
     // Apply initial viewport clip.
     Optional<ClipRecorder> clipRecorder;
     if (m_layoutSVGRoot.shouldApplyViewportClip()) {
         // TODO(pdr): Clip the paint info cull rect here.
         clipRecorder.emplace(paintInfoBeforeFiltering.context, m_layoutSVGRoot, paintInfoBeforeFiltering.displayItemTypeForClipping(), LayoutRect(pixelSnappedIntRect(m_layoutSVGRoot.overflowClipRect(paintOffset))));
     }
 
     // Convert from container offsets (html layoutObjects) to a relative transform (svg layoutObjects).
     // Transform from our paint container's coordinate system to our local coords.
-    IntPoint adjustedPaintOffset = roundedIntPoint(paintOffset);
-    AffineTransform paintOffsetToBorderBox = AffineTransform::translation(adjustedPaintOffset.x(), adjustedPaintOffset.y()) * m_layoutSVGRoot.localToBorderBoxTransform();
+    AffineTransform paintOffsetToBorderBox =
+        AffineTransform::translation(adjustedRect.x(), adjustedRect.y());
+    // Compensate for size snapping.
+    paintOffsetToBorderBox.scale(
+        adjustedRect.width() / m_layoutSVGRoot.size().width().toFloat(),
+        adjustedRect.height() / m_layoutSVGRoot.size().height().toFloat());
+    paintOffsetToBorderBox.multiply(m_layoutSVGRoot.localToBorderBoxTransform());
+
     paintInfoBeforeFiltering.updateCullRect(paintOffsetToBorderBox);
     TransformRecorder transformRecorder(paintInfoBeforeFiltering.context, m_layoutSVGRoot, paintOffsetToBorderBox);
 
     SVGPaintContext paintContext(m_layoutSVGRoot, paintInfoBeforeFiltering);
     if (paintContext.paintInfo().phase == PaintPhaseForeground && !paintContext.applyClipMaskAndFilterIfNecessary())
         return;
 
     BoxPainter(m_layoutSVGRoot).paint(paintContext.paintInfo(), LayoutPoint());
 
     PaintTiming& timing = PaintTiming::from(m_layoutSVGRoot.node()->document().topDocument());
     timing.markFirstContentfulPaint();
 }
 
 } // namespace blink