Merge two determineFilterPrimitiveSubregion implementations

Source/core/platform/graphics/filters/FilterEffect.cpp

 /*
  * Copyright (C) 2008 Alex Mathews <possessedpenguinbob@gmail.com>
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  * Copyright (C) 2012 University of Szeged
  * Copyright (C) 2013 Google Inc. 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 419 matching lines @@
         m_premultipliedImageResult.clear();
 }
 
 TextStream& FilterEffect::externalRepresentation(TextStream& ts, int) const
 {
     // FIXME: We should dump the subRegions of the filter primitives here later. This isn't
     // possible at the moment, because we need more detailed informations from the target object.
     return ts;
 }
 
-FloatRect FilterEffect::determineFilterPrimitiveSubregion()
+FloatRect FilterEffect::determineFilterPrimitiveSubregion(bool mapRectForward, bool clipToFilterRegion)
 {
     ASSERT(filter());
 
     // FETile, FETurbulence, FEFlood don't have input effects, take the filter region as unite rect.
     FloatRect subregion;
     if (unsigned numberOfInputEffects = inputEffects().size()) {
-        subregion = inputEffect(0)->determineFilterPrimitiveSubregion();
+        subregion = inputEffect(0)->determineFilterPrimitiveSubregion(mapRectForward, clipToFilterRegion);
         for (unsigned i = 1; i < numberOfInputEffects; ++i)
-            subregion.unite(inputEffect(i)->determineFilterPrimitiveSubregion());
+            subregion.unite(inputEffect(i)->determineFilterPrimitiveSubregion(mapRectForward, clipToFilterRegion));
     } else
         subregion = filter()->filterRegion();
 
     // After calling determineFilterPrimitiveSubregion on the target effect, reset the subregion again for <feTile>.
     if (filterEffectType() == FilterEffectTypeTile)
         subregion = filter()->filterRegion();
 
-    subregion = mapRect(subregion);
+    if (mapRectForward)
+        subregion = mapRect(subregion);
 
     FloatRect boundaries = effectBoundaries();
     if (hasX())
         subregion.setX(boundaries.x());
     if (hasY())
         subregion.setY(boundaries.y());
     if (hasWidth())
         subregion.setWidth(boundaries.width());
     if (hasHeight())
         subregion.setHeight(boundaries.height());
 
     setFilterPrimitiveSubregion(subregion);
 
     FloatRect absoluteSubregion = filter()->absoluteTransform().mapRect(subregion);
     FloatSize filterResolution = filter()->filterResolution();
     absoluteSubregion.scale(filterResolution.width(), filterResolution.height());
 
+    // Clip every filter effect to the filter region.
+    if (clipToFilterRegion) {
+        FloatRect absoluteScaledFilterRegion = filter()->absoluteFilterRegion();
+        absoluteScaledFilterRegion.scale(filterResolution.width(), filterResolution.height());
+        absoluteSubregion.intersect(absoluteScaledFilterRegion);
+    }
+
     setMaxEffectRect(absoluteSubregion);
     return subregion;
 }
 
 PassRefPtr<SkImageFilter> FilterEffect::createImageFilter(SkiaImageFilterBuilder* builder)
 {
     return 0;
 }
 
 SkImageFilter::CropRect FilterEffect::getCropRect(const FloatSize& cropOffset) const
@@ skipping 17 matching lines @@
         flags |= SkImageFilter::CropRect::kHasRight_CropEdge;
     }
     if (hasHeight()) {
         rect.fBottom = rect.fTop + boundaries.height();
         flags |= SkImageFilter::CropRect::kHasBottom_CropEdge;
     }
     return SkImageFilter::CropRect(rect, flags);
 }
 
 } // namespace WebCore