Decouple content transform fiddling from SVGRenderingContext::renderSubtree

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 165 matching lines @@
 
     m_renderingFlags |= RenderingPrepared;
 }
 
 static AffineTransform& currentContentTransformation()
 {
     DEFINE_STATIC_LOCAL(AffineTransform, s_currentContentTransformation, ());
     return s_currentContentTransformation;
 }
 
+SubtreeContentTransformScope::SubtreeContentTransformScope(const AffineTransform& subtreeContentTransformation)
+{
+    AffineTransform& contentTransformation = currentContentTransformation();
+    m_savedContentTransformation = contentTransformation;
+    contentTransformation = subtreeContentTransformation * contentTransformation;
+}
+
+SubtreeContentTransformScope::~SubtreeContentTransformScope()
+{
+    currentContentTransformation() = m_savedContentTransformation;
+}
+
 float SVGRenderingContext::calculateScreenFontSizeScalingFactor(const RenderObject* renderer)
 {
     ASSERT(renderer);
 
     AffineTransform 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));
 }
@@ skipping 29 matching lines @@
 
         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)
+void SVGRenderingContext::renderSubtree(GraphicsContext* context, RenderObject* item)
 {
+    ASSERT(context);
     ASSERT(item);
-    ASSERT(context);
+    ASSERT(!item->needsLayout());
 
     PaintInfo info(context, PaintInfo::infiniteRect(), PaintPhaseForeground, PaintBehaviorNormal);
-
-    AffineTransform& contentTransformation = currentContentTransformation();
-    AffineTransform savedContentTransformation = contentTransformation;
-    contentTransformation = subtreeContentTransformation * contentTransformation;
-
-    ASSERT(!item->needsLayout());
     item->paint(info, IntPoint());
-
-    contentTransformation = savedContentTransformation;
 }
 
 FloatRect SVGRenderingContext::clampedAbsoluteTargetRect(const FloatRect& absoluteTargetRect)
 {
     const FloatSize maxImageBufferSize(kMaxImageBufferSize, kMaxImageBufferSize);
     return FloatRect(absoluteTargetRect.location(), absoluteTargetRect.size().shrunkTo(maxImageBufferSize));
 }
 
 void SVGRenderingContext::clear2DRotation(AffineTransform& transform)
 {
@@ skipping 28 matching lines @@
             SVGImagePainter::paintForeground(toRenderSVGImage(*m_object), bufferedInfo);
         } else
             return false;
     }
 
     m_paintInfo->context->drawImageBuffer(imageBuffer.get(), boundingBox);
     return true;
 }
 
 } // namespace blink