feComposite filter does not clip the paint rect to its effect rect wh…

…en the operator is 'in' or 'atop'

https://bugs.webkit.org/show_bug.cgi?id=137856

Patch by Said Abou-Hallawa <sabouhallawa@apple.com> on 2015-06-09
Reviewed by Darin Adler.

Source/WebCore:

There was bug in calculating the absolutePaintRect of the feComposite filter
when the operator is equal to 'in' or 'atop'. The absolutePaintRect was set
to the absolutePaintRect of the background FilterEffect which is correct.
What was missing is clipping this rectangle to the maxEffectRect of the
filter which we do for other operators.

Tests: svg/filters/feComposite-background-rect-control-operators.svg

* platform/graphics/IntRect.h:
(WebCore::operator-=):
(WebCore::operator-): Add new operators to IntRect.

* platform/graphics/filters/FEComposite.cpp:
(WebCore::FEComposite::determineAbsolutePaintRect): Make sure the filter
absolutePaintRect is clipped to maxEffectRect for all operators.

(WebCore::FEComposite::platformApplySoftware): Code clean-up.

* platform/graphics/filters/FilterEffect.cpp:
(WebCore::FilterEffect::determineAbsolutePaintRect): Move the clipping
part to a separate function.

(WebCore::FilterEffect::clipAbsolutePaintRect): Clip the absolutePaintRect
to the maxEffectRect of the filter.

* platform/graphics/filters/FilterEffect.h:

LayoutTests:

* svg/filters/feComposite-background-rect-control-operators-expected.svg: Added.
* svg/filters/feComposite-background-rect-control-operators.svg: Added.
Ensure the painting rect of the feComposite filter with operator 'in' or
'atop' is clipped to its bounding rectangle

Canonical link: https://commits.webkit.org/163864@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@185392 268f45cc-cd09-0410-ab3c-d52691b4dbfc

LayoutTests/ChangeLog

@@ -1,3 +1,15 @@
+2015-06-09  Said Abou-Hallawa  <sabouhallawa@apple.com>
+
+        feComposite filter does not clip the paint rect to its effect rect when the operator is 'in' or 'atop'
+        https://bugs.webkit.org/show_bug.cgi?id=137856
+
+        Reviewed by Darin Adler.
+
+        * svg/filters/feComposite-background-rect-control-operators-expected.svg: Added.
+        * svg/filters/feComposite-background-rect-control-operators.svg: Added.
+        Ensure the painting rect of the feComposite filter with operator 'in' or
+        'atop' is clipped to its bounding rectangle
+
 2015-06-09  Yusuke Suzuki  <utatane.tea@gmail.com>
 
         Introduce getter definition into static hash tables and use it for getters in RegExp.prototype.

Source/WebCore/ChangeLog

@@ -1,3 +1,37 @@
+2015-06-09  Said Abou-Hallawa  <sabouhallawa@apple.com>
+
+        feComposite filter does not clip the paint rect to its effect rect when the operator is 'in' or 'atop'
+        https://bugs.webkit.org/show_bug.cgi?id=137856
+
+        Reviewed by Darin Adler.
+
+        There was bug in calculating the absolutePaintRect of the feComposite filter
+        when the operator is equal to 'in' or 'atop'. The absolutePaintRect was set
+        to the absolutePaintRect of the background FilterEffect which is correct.
+        What was missing is clipping this rectangle to the maxEffectRect of the
+        filter which we do for other operators.
+
+        Tests: svg/filters/feComposite-background-rect-control-operators.svg
+
+        * platform/graphics/IntRect.h:
+        (WebCore::operator-=):
+        (WebCore::operator-): Add new operators to IntRect.
+
+        * platform/graphics/filters/FEComposite.cpp:
+        (WebCore::FEComposite::determineAbsolutePaintRect): Make sure the filter
+        absolutePaintRect is clipped to maxEffectRect for all operators.
+
+        (WebCore::FEComposite::platformApplySoftware): Code clean-up.
+
+        * platform/graphics/filters/FilterEffect.cpp:
+        (WebCore::FilterEffect::determineAbsolutePaintRect): Move the clipping
+        part to a separate function.
+
+        (WebCore::FilterEffect::clipAbsolutePaintRect): Clip the absolutePaintRect
+        to the maxEffectRect of the filter.
+
+        * platform/graphics/filters/FilterEffect.h:
+
 2015-06-09  Matt Rajca  <mrajca@apple.com>
 
         Implement MediaSessionManager to keep track of all MediaSessions.

Source/WebCore/platform/graphics/IntRect.h

@@ -216,6 +216,18 @@ inline bool operator!=(const IntRect& a, const IntRect& b)
     return a.location() != b.location() || a.size() != b.size();
 }
 
+inline IntRect& operator-=(IntRect& r, const IntPoint& offset)
+{
+    r.move(-offset.x(), -offset.y());
+    return r;
+}
+
+inline IntRect operator-(const IntRect& r, const IntPoint& offset)
+{
+    IntRect t = r;
+    return t -= offset;
+}
+
 #if USE(CG)
 WEBCORE_EXPORT IntRect enclosingIntRect(const CGRect&);
 #endif

Source/WebCore/platform/graphics/filters/FEComposite.cpp

@@ -235,6 +235,7 @@ void FEComposite::determineAbsolutePaintRect()
         // For In and Atop the first effect just influences the result of
         // the second effect. So just use the absolute paint rect of the second effect here.
         setAbsolutePaintRect(inputEffect(1)->absolutePaintRect());
+        clipAbsolutePaintRect();
         return;
     case FECOMPOSITE_OPERATOR_ARITHMETIC:
         // Arithmetic may influnce the compele filter primitive region. So we can't
@@ -290,13 +291,11 @@ void FEComposite::platformApplySoftware()
         destinationRect.intersect(absolutePaintRect());
         if (destinationRect.isEmpty())
             break;
-        IntPoint destinationPoint(destinationRect.x() - absolutePaintRect().x(), destinationRect.y() - absolutePaintRect().y());
-        IntRect sourceRect(IntPoint(destinationRect.x() - in->absolutePaintRect().x(),
-                                    destinationRect.y() - in->absolutePaintRect().y()), destinationRect.size());
-        IntRect source2Rect(IntPoint(destinationRect.x() - in2->absolutePaintRect().x(),
-                                     destinationRect.y() - in2->absolutePaintRect().y()), destinationRect.size());
-        filterContext->drawImageBuffer(imageBuffer2, ColorSpaceDeviceRGB, IntRect(destinationPoint, source2Rect.size()), source2Rect);
-        filterContext->drawImageBuffer(imageBuffer, ColorSpaceDeviceRGB, IntRect(destinationPoint, sourceRect.size()), sourceRect, CompositeSourceIn);
+        IntRect adjustedDestinationRect = destinationRect - absolutePaintRect().location();
+        IntRect sourceRect = destinationRect - in->absolutePaintRect().location();
+        IntRect source2Rect = destinationRect - in2->absolutePaintRect().location();
+        filterContext->drawImageBuffer(imageBuffer2, ColorSpaceDeviceRGB, adjustedDestinationRect, source2Rect);
+        filterContext->drawImageBuffer(imageBuffer, ColorSpaceDeviceRGB, adjustedDestinationRect, sourceRect, CompositeSourceIn);
         break;
     }
     case FECOMPOSITE_OPERATOR_OUT:

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

@@ -56,16 +56,18 @@ FilterEffect::~FilterEffect()
 void FilterEffect::determineAbsolutePaintRect()
 {
     m_absolutePaintRect = IntRect();
-    unsigned size = m_inputEffects.size();
-    for (unsigned i = 0; i < size; ++i)
-        m_absolutePaintRect.unite(m_inputEffects.at(i)->absolutePaintRect());
-
+    for (auto& effect : m_inputEffects)
+        m_absolutePaintRect.unite(effect->absolutePaintRect());
+    clipAbsolutePaintRect();
+}
+
+void FilterEffect::clipAbsolutePaintRect()
+{
     // Filters in SVG clip to primitive subregion, while CSS doesn't.
     if (m_clipsToBounds)
         m_absolutePaintRect.intersect(enclosingIntRect(m_maxEffectRect));
     else
         m_absolutePaintRect.unite(enclosingIntRect(m_maxEffectRect));
-
 }
 
 IntRect FilterEffect::requestedRegionOfInputImageData(const IntRect& effectRect) const

Source/WebCore/platform/graphics/filters/FilterEffect.h

@@ -177,6 +177,8 @@ class FilterEffect : public RefCounted<FilterEffect> {
     // If a pre-multiplied image, check every pixel for validity and correct if necessary.
     void forceValidPreMultipliedPixels();
 
+    void clipAbsolutePaintRect();
+
 private:
     std::unique_ptr<ImageBuffer> m_imageBufferResult;
     RefPtr<Uint8ClampedArray> m_unmultipliedImageResult;