2011-04-10 Simon Fraser <simon.fraser@apple.com>

        Reviewed by Ariya Hidayat.

        Allow ShadowBlur to re-use the last buffer if it already contains the correct shadow
        https://bugs.webkit.org/show_bug.cgi?id=58161

        ShadowBlur already has a singleton scratch buffer that is re-used
        between shadows. Enhance use of this scratch buffer to avoid drawing
        and blurring the shadow if the results will match what is already
        in the buffer.

        Cleaned up ShadowBlur code to remove beginShadowLayer() and endShadowLayer(),
        which ended up with little reusable code after adding the re-use logic.

        * platform/graphics/FloatRect.cpp:
        (WebCore::enclosingIntRect): Replace safeFloatToInt() with the existing
        clampToInteger() from MathExtras.h

        * platform/graphics/FloatSize.h:
        (WebCore::expandedIntSize): New method to safely ceil() the size.

        * platform/graphics/RoundedIntRect.h:
        Add operator== for Radii and RoundedIntRect.

        * platform/graphics/ShadowBlur.cpp:
        (WebCore::ScratchBuffer::ScratchBuffer):
        (WebCore::ScratchBuffer::setLastShadowValues):
        (WebCore::ScratchBuffer::setLastInsetShadowValues):
        (WebCore::ScratchBuffer::matchesLastShadow):
        (WebCore::ScratchBuffer::matchesLastInsetShadow):
        (WebCore::ScratchBuffer::clearScratchBuffer):
        Have the scratch buffer remember what shadow parameters were used
        to render the buffer contents.

        (WebCore::ShadowBlur::drawShadowBuffer):
        Renamed from endShadowLayer(), and only contains the drawing
        logic now.

        (WebCore::ShadowBlur::drawRectShadow):
        Promote some code from beginShadowLayer().

        (WebCore::ShadowBlur::drawInsetShadow):
        Promote some code from beginShadowLayer().

        (WebCore::ShadowBlur::drawRectShadowWithoutTiling):
        (WebCore::ShadowBlur::drawInsetShadowWithoutTiling):
        (WebCore::ShadowBlur::drawInsetShadowWithTiling):
        (WebCore::ShadowBlur::drawRectShadowWithTiling):
        These methods now check to see if the buffer already matches
        their required parameters, and avoid work if it does.

        (WebCore::ShadowBlur::blurShadowBuffer):
        Factored some code into this new method.

        (WebCore::ShadowBlur::blurAndColorShadowBuffer):
        Minor refactoring.

        * platform/graphics/ShadowBlur.h:

Canonical link: https://commits.webkit.org/73194@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@83422 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/ChangeLog

@@ -1,3 +1,63 @@
+2011-04-10  Simon Fraser  <simon.fraser@apple.com>
+
+        Reviewed by Ariya Hidayat.
+
+        Allow ShadowBlur to re-use the last buffer if it already contains the correct shadow
+        https://bugs.webkit.org/show_bug.cgi?id=58161
+
+        ShadowBlur already has a singleton scratch buffer that is re-used
+        between shadows. Enhance use of this scratch buffer to avoid drawing
+        and blurring the shadow if the results will match what is already
+        in the buffer.
+
+        Cleaned up ShadowBlur code to remove beginShadowLayer() and endShadowLayer(),
+        which ended up with little reusable code after adding the re-use logic.
+
+        * platform/graphics/FloatRect.cpp:
+        (WebCore::enclosingIntRect): Replace safeFloatToInt() with the existing
+        clampToInteger() from MathExtras.h
+
+        * platform/graphics/FloatSize.h:
+        (WebCore::expandedIntSize): New method to safely ceil() the size.
+
+        * platform/graphics/RoundedIntRect.h:
+        Add operator== for Radii and RoundedIntRect.
+
+        * platform/graphics/ShadowBlur.cpp:
+        (WebCore::ScratchBuffer::ScratchBuffer):
+        (WebCore::ScratchBuffer::setLastShadowValues):
+        (WebCore::ScratchBuffer::setLastInsetShadowValues):
+        (WebCore::ScratchBuffer::matchesLastShadow):
+        (WebCore::ScratchBuffer::matchesLastInsetShadow):
+        (WebCore::ScratchBuffer::clearScratchBuffer):
+        Have the scratch buffer remember what shadow parameters were used
+        to render the buffer contents.
+
+        (WebCore::ShadowBlur::drawShadowBuffer):
+        Renamed from endShadowLayer(), and only contains the drawing
+        logic now.
+
+        (WebCore::ShadowBlur::drawRectShadow):
+        Promote some code from beginShadowLayer().
+
+        (WebCore::ShadowBlur::drawInsetShadow):
+        Promote some code from beginShadowLayer().
+
+        (WebCore::ShadowBlur::drawRectShadowWithoutTiling):
+        (WebCore::ShadowBlur::drawInsetShadowWithoutTiling):
+        (WebCore::ShadowBlur::drawInsetShadowWithTiling):
+        (WebCore::ShadowBlur::drawRectShadowWithTiling):
+        These methods now check to see if the buffer already matches
+        their required parameters, and avoid work if it does.
+
+        (WebCore::ShadowBlur::blurShadowBuffer):
+        Factored some code into this new method.
+
+        (WebCore::ShadowBlur::blurAndColorShadowBuffer):
+        Minor refactoring.
+
+        * platform/graphics/ShadowBlur.h:
+
 2011-04-10  Geoffrey Garen  <ggaren@apple.com>
 
         Build fix: Updated for file move.

Source/WebCore/platform/graphics/FloatRect.cpp

@@ -30,8 +30,8 @@
 #include "FloatConversion.h"
 #include "IntRect.h"
 #include <algorithm>
-#include <limits>
 #include <math.h>
+#include <wtf/MathExtras.h>
 
 using std::max;
 using std::min;
@@ -182,26 +182,14 @@ void FloatRect::fitToPoints(const FloatPoint& p0, const FloatPoint& p1, const Fl
     setLocationAndSizeFromEdges(left, top, right, bottom);
 }
 
-static inline int safeFloatToInt(float x)
-{
-    static const int s_intMax = std::numeric_limits<int>::max();
-    static const int s_intMin = std::numeric_limits<int>::min();
-
-    if (x >= static_cast<float>(s_intMax))
-        return s_intMax;
-    if (x < static_cast<float>(s_intMin))
-        return s_intMin;
-    return static_cast<int>(x);
-}
-
 IntRect enclosingIntRect(const FloatRect& rect)
 {
     float left = floorf(rect.x());
     float top = floorf(rect.y());
     float width = ceilf(rect.maxX()) - left;
     float height = ceilf(rect.maxY()) - top;
-    return IntRect(safeFloatToInt(left), safeFloatToInt(top), 
-                   safeFloatToInt(width), safeFloatToInt(height));
+    return IntRect(clampToInteger(left), clampToInteger(top), 
+                   clampToInteger(width), clampToInteger(height));
 }
 
 FloatRect mapRect(const FloatRect& r, const FloatRect& srcRect, const FloatRect& destRect)

Source/WebCore/platform/graphics/FloatSize.h

@@ -148,6 +148,11 @@ inline IntSize roundedIntSize(const FloatSize& p)
     return IntSize(static_cast<int>(roundf(p.width())), static_cast<int>(roundf(p.height())));
 }
 
+inline IntSize expandedIntSize(const FloatSize& p)
+{
+    return IntSize(clampToInteger(ceilf(p.width())), clampToInteger(ceilf(p.height())));
+}
+
 } // namespace WebCore
 
 #endif // FloatSize_h

Source/WebCore/platform/graphics/RoundedIntRect.h

@@ -98,6 +98,17 @@ class RoundedIntRect {
     Radii m_radii;
 };
 
+inline bool operator==(const RoundedIntRect::Radii& a, const RoundedIntRect::Radii& b)
+{
+    return a.topLeft() == b.topLeft() && a.topRight() == b.topRight() && a.bottomLeft() == b.bottomLeft() && a.bottomRight() == b.bottomRight();
+}
+
+inline bool operator==(const RoundedIntRect& a, const RoundedIntRect& b)
+{
+    return a.rect() == b.rect() && a.radii() == b.radii();
+}
+
+
 } // namespace WebCore
 
 #endif // RoundedIntRect_h