[SVG] Poor filter resolution when using CSS 3D transforms.

Source/core/rendering/svg/SVGRenderingContext.cpp

 /*
  * Copyright (C) 2007, 2008 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Google, Inc.  All rights reserved.
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
  * Copyright (C) Research In Motion Limited 2009-2010. 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
@@ skipping 185 matching lines @@
 {
     DEFINE_STATIC_LOCAL(AffineTransform, s_currentContentTransformation, ());
     return s_currentContentTransformation;
 }
 
 float SVGRenderingContext::calculateScreenFontSizeScalingFactor(const RenderObject* renderer)
 {
     ASSERT(renderer);
 
     AffineTransform ctm;
-    calculateTransformationToOutermostCoordinateSystem(renderer, ctm);
+    // FIXME: calculateDeviceSpaceTransformation() queries layer compositing state - which is not
+    // supported during layout. Hence, the result may not include all CSS transforms.
+    calculateDeviceSpaceTransformation(renderer, ctm);
     return narrowPrecisionToFloat(sqrt((pow(ctm.xScale(), 2) + pow(ctm.yScale(), 2)) / 2));
 }
 
-void SVGRenderingContext::calculateTransformationToOutermostCoordinateSystem(const RenderObject* renderer, AffineTransform& absoluteTransform)
+void SVGRenderingContext::calculateDeviceSpaceTransformation(const RenderObject* renderer, AffineTransform& absoluteTransform)
 {
+    // FIXME: trying to compute a device space transform at record time is wrong. All clients
+    // should be updated to avoid relying on this information, and the method should be removed.
+
     ASSERT(renderer);
     // We're about to possibly clear renderer, so save the deviceScaleFactor now.
     float deviceScaleFactor = renderer->document().frameHost()->deviceScaleFactor();
 
     // Walk up the render tree, accumulating SVG transforms.
     absoluteTransform = currentContentTransformation();
     while (renderer) {
         absoluteTransform = renderer->localToParentTransform() * absoluteTransform;
         if (renderer->isSVGRoot())
             break;
         renderer = renderer->parent();
     }
 
     // Continue walking up the layer tree, accumulating CSS transforms.
     RenderLayer* layer = renderer ? renderer->enclosingLayer() : 0;
-    while (layer) {
-        if (TransformationMatrix* layerTransform = layer->transform())
-            absoluteTransform = layerTransform->toAffineTransform() * absoluteTransform;
-
+    while (layer && layer->isAllowedToQueryCompositingState()) {
         // We can stop at compositing layers, to match the backing resolution.
         // FIXME: should we be computing the transform to the nearest composited layer,
         // or the nearest composited layer that does not paint into its ancestor?
         // I think this is the nearest composited ancestor since we will inherit its
         // transforms in the composited layer tree.
-        if (layer->hasCompositedLayerMapping())
+        if (layer->compositingState() != NotComposited)
             break;
 
+        if (TransformationMatrix* layerTransform = layer->transform())
+            absoluteTransform = layerTransform->toAffineTransform() * absoluteTransform;
+
         layer = layer->parent();
     }
 
     absoluteTransform.scale(deviceScaleFactor);
 }
 
 void SVGRenderingContext::renderSubtree(GraphicsContext* context, RenderObject* item, const AffineTransform& subtreeContentTransformation)
 {
     ASSERT(item);
     ASSERT(context);
@@ skipping 49 matching lines @@
             toRenderSVGImage(m_object)->paintForeground(bufferedInfo);
         } else
             return false;
     }
 
     m_paintInfo->context->drawImageBuffer(imageBuffer.get(), boundingBox);
     return true;
 }
 
 }