Proposal: Add support for even-odd fill and clip to Canvas

https://bugs.webkit.org/show_bug.cgi?id=106188

Patch by Rik Cabanier <cabanier@adobe.com> on 2013-01-21
Reviewed by Dirk Schulze.

Source/WebCore:

This patch adds support for an optional winding rule to fill, clip
and isPointInPath in canvas 2d. By default, the fill is non-zero but
you can now pass in an optional winding rule string ("nonzero" or "evenodd")
to make an explicit choice.

Tests: fast/canvas/canvas-clip-rule.html
       fast/canvas/canvas-fill-rule.html
       fast/canvas/canvas-isPointInPath-winding.html

* html/canvas/CanvasRenderingContext2D.cpp: Change implementation so it sets the windig rule in the context.
(WebCore::parseWinding):
(WebCore):
(WebCore::CanvasRenderingContext2D::fill):
(WebCore::CanvasRenderingContext2D::clip):
(WebCore::CanvasRenderingContext2D::isPointInPath):
* html/canvas/CanvasRenderingContext2D.h:
(CanvasRenderingContext2D):
* html/canvas/CanvasRenderingContext2D.idl: Change the idl so the new API is exposed to JavaScript.
* platform/graphics/cg/GraphicsContextCG.cpp: Fixes a bug where the wrong winding rule was set for clipping in Core Graphics.
(WebCore::GraphicsContext::clip):

LayoutTests:

Add tests to verify that the winding rule work as expected with clip, fill and isPointInPath

* fast/canvas/canvas-clip-rule-expected.txt: Added.
* fast/canvas/canvas-clip-rule.html: Added.
* fast/canvas/canvas-fill-rule-expected.txt: Added.
* fast/canvas/canvas-fill-rule.html: Added.
* fast/canvas/canvas-isPointInPath-winding-expected.txt: Added.
* fast/canvas/canvas-isPointInPath-winding.html: Added.
* fast/canvas/script-tests/canvas-clip-rule.js: Added.
(pixelDataAtPoint):
(checkResult):
(prepareTestScenario):
* fast/canvas/script-tests/canvas-fill-rule.js: Added.
(pixelDataAtPoint):
(checkResult):
(prepareTestScenario):
* fast/canvas/script-tests/canvas-isPointInPath-winding.js: Added.
(prepareTestScenario):

git-svn-id: svn://svn.chromium.org/blink/trunk@140352 bbb929c8-8fbe-4397-9dbb-9b2b20218538

15 files changed, 375 insertions, 12 deletions

diff --git a/third_party/WebKit/LayoutTests/ChangeLog b/third_party/WebKit/LayoutTests/ChangeLog
index 3af543c..ffc3737 100644
--- a/third_party/WebKit/LayoutTests/ChangeLog
+++ b/third_party/WebKit/LayoutTests/ChangeLog
@@ -1,3 +1,29 @@
+2013-01-21  Rik Cabanier  <cabanier@adobe.com>
+
+        Proposal: Add support for even-odd fill and clip to Canvas
+        https://bugs.webkit.org/show_bug.cgi?id=106188
+
+        Reviewed by Dirk Schulze.
+
+        Add tests to verify that the winding rule work as expected with clip, fill and isPointInPath
+
+        * fast/canvas/canvas-clip-rule-expected.txt: Added.
+        * fast/canvas/canvas-clip-rule.html: Added.
+        * fast/canvas/canvas-fill-rule-expected.txt: Added.
+        * fast/canvas/canvas-fill-rule.html: Added.
+        * fast/canvas/canvas-isPointInPath-winding-expected.txt: Added.
+        * fast/canvas/canvas-isPointInPath-winding.html: Added.
+        * fast/canvas/script-tests/canvas-clip-rule.js: Added.
+        (pixelDataAtPoint):
+        (checkResult):
+        (prepareTestScenario):
+        * fast/canvas/script-tests/canvas-fill-rule.js: Added.
+        (pixelDataAtPoint):
+        (checkResult):
+        (prepareTestScenario):
+        * fast/canvas/script-tests/canvas-isPointInPath-winding.js: Added.
+        (prepareTestScenario):
+
 2013-01-21  ChangSeok Oh  <shivamidow@gmail.com>
 
         [Texmap][GTK] The poster-circle doesn't appear.
diff --git a/third_party/WebKit/LayoutTests/fast/canvas/canvas-clip-rule-expected.txt b/third_party/WebKit/LayoutTests/fast/canvas/canvas-clip-rule-expected.txt
new file mode 100644
index 0000000..eb71dc9
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/fast/canvas/canvas-clip-rule-expected.txt
@@ -0,0 +1,27 @@
+Series of tests to ensure correct results of the winding rule.
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+Testing default clip
+PASS pixelDataAtPoint()[0] is within 5 of 0
+PASS pixelDataAtPoint()[1] is within 5 of 255
+PASS pixelDataAtPoint()[2] is within 5 of 0
+PASS pixelDataAtPoint()[3] is within 5 of 255
+
+Testing nonzero clip
+PASS pixelDataAtPoint()[0] is within 5 of 0
+PASS pixelDataAtPoint()[1] is within 5 of 255
+PASS pixelDataAtPoint()[2] is within 5 of 0
+PASS pixelDataAtPoint()[3] is within 5 of 255
+
+Testing evenodd clip
+PASS pixelDataAtPoint()[0] is within 5 of 255
+PASS pixelDataAtPoint()[1] is within 5 of 0
+PASS pixelDataAtPoint()[2] is within 5 of 0
+PASS pixelDataAtPoint()[3] is within 5 of 255
+
+PASS successfullyParsed is true
+
+TEST COMPLETE
+
diff --git a/third_party/WebKit/LayoutTests/fast/canvas/canvas-clip-rule.html b/third_party/WebKit/LayoutTests/fast/canvas/canvas-clip-rule.html
new file mode 100644
index 0000000..af1b8f3
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/fast/canvas/canvas-clip-rule.html
@@ -0,0 +1,9 @@
+<!doctype html>
+<html>
+<head>
+<script src="../js/resources/js-test-pre.js"></script>
+</head>
+<body>
+<script src="script-tests/canvas-clip-rule.js"></script>
+<script src="../js/resources/js-test-post.js"></script>
+</body>
\ No newline at end of file
diff --git a/third_party/WebKit/LayoutTests/fast/canvas/canvas-fill-rule-expected.txt b/third_party/WebKit/LayoutTests/fast/canvas/canvas-fill-rule-expected.txt
new file mode 100644
index 0000000..956e134
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/fast/canvas/canvas-fill-rule-expected.txt
@@ -0,0 +1,27 @@
+Series of tests to ensure correct results of the winding rule.
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+Testing default fill
+PASS pixelDataAtPoint()[0] is within 5 of 0
+PASS pixelDataAtPoint()[1] is within 5 of 255
+PASS pixelDataAtPoint()[2] is within 5 of 0
+PASS pixelDataAtPoint()[3] is within 5 of 255
+
+Testing nonzero fill
+PASS pixelDataAtPoint()[0] is within 5 of 0
+PASS pixelDataAtPoint()[1] is within 5 of 255
+PASS pixelDataAtPoint()[2] is within 5 of 0
+PASS pixelDataAtPoint()[3] is within 5 of 255
+
+Testing evenodd fill
+PASS pixelDataAtPoint()[0] is within 5 of 255
+PASS pixelDataAtPoint()[1] is within 5 of 0
+PASS pixelDataAtPoint()[2] is within 5 of 0
+PASS pixelDataAtPoint()[3] is within 5 of 255
+
+PASS successfullyParsed is true
+
+TEST COMPLETE
+
diff --git a/third_party/WebKit/LayoutTests/fast/canvas/canvas-fill-rule.html b/third_party/WebKit/LayoutTests/fast/canvas/canvas-fill-rule.html
new file mode 100644
index 0000000..f7ae9db
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/fast/canvas/canvas-fill-rule.html
@@ -0,0 +1,9 @@
+<!doctype html>
+<html>
+<head>
+<script src="../js/resources/js-test-pre.js"></script>
+</head>
+<body>
+<script src="script-tests/canvas-fill-rule.js"></script>
+<script src="../js/resources/js-test-post.js"></script>
+</body>
\ No newline at end of file
diff --git a/third_party/WebKit/LayoutTests/fast/canvas/canvas-isPointInPath-winding-expected.txt b/third_party/WebKit/LayoutTests/fast/canvas/canvas-isPointInPath-winding-expected.txt
new file mode 100644
index 0000000..611e068
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/fast/canvas/canvas-isPointInPath-winding-expected.txt
@@ -0,0 +1,18 @@
+Series of tests to ensure correct results of the winding rule in isPointInPath.
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+Testing default isPointInPath
+PASS ctx.isPointInPath(50, 50) is true
+
+Testing nonzero isPointInPath
+PASS ctx.isPointInPath(50, 50, 'nonzero') is true
+
+Testing evenodd isPointInPath
+PASS ctx.isPointInPath(50, 50, 'evenodd') is false
+
+PASS successfullyParsed is true
+
+TEST COMPLETE
+
diff --git a/third_party/WebKit/LayoutTests/fast/canvas/canvas-isPointInPath-winding.html b/third_party/WebKit/LayoutTests/fast/canvas/canvas-isPointInPath-winding.html
new file mode 100644
index 0000000..0ae4d9a
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/fast/canvas/canvas-isPointInPath-winding.html
@@ -0,0 +1,9 @@
+<!doctype html>
+<html>
+<head>
+<script src="../js/resources/js-test-pre.js"></script>
+</head>
+<body>
+<script src="script-tests/canvas-isPointInPath-winding.js"></script>
+<script src="../js/resources/js-test-post.js"></script>
+</body>
\ No newline at end of file
diff --git a/third_party/WebKit/LayoutTests/fast/canvas/script-tests/canvas-clip-rule.js b/third_party/WebKit/LayoutTests/fast/canvas/script-tests/canvas-clip-rule.js
new file mode 100644
index 0000000..e6a45ed
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/fast/canvas/script-tests/canvas-clip-rule.js
@@ -0,0 +1,69 @@
+description("Series of tests to ensure correct results of the winding rule.");
+
+
+var tmpimg = document.createElement('canvas');
+tmpimg.width = 200;
+tmpimg.height = 200;
+ctx = tmpimg.getContext('2d');
+
+// Create the image for blending test with images.
+var img = document.createElement('canvas');
+img.width = 100;
+img.height = 100;
+var imgCtx = img.getContext('2d');
+
+function pixelDataAtPoint()
+{
+  return ctx.getImageData(50, 50, 1, 1).data;
+}
+
+function checkResult(expectedColors, sigma) {
+    for (var i = 0; i < 4; i++)
+	    shouldBeCloseTo("pixelDataAtPoint()[" + i + "]", expectedColors[i], sigma);
+}
+
+// Execute test.
+function prepareTestScenario() {
+    debug('Testing default clip');
+    ctx.fillStyle = 'rgb(255,0,0)';
+    ctx.fillRect(0, 0, 100, 100);
+    ctx.fillStyle = 'rgb(0,255,0)';
+    ctx.beginPath();
+    ctx.rect(0, 0, 100, 100);
+    ctx.rect(25, 25, 50, 50);
+    ctx.clip();
+    ctx.beginPath();
+    ctx.fillRect(0, 0, 100, 100);
+    checkResult([0, 255, 0, 255], 5);                        
+    debug('');
+
+    debug('Testing nonzero clip');
+    ctx.fillStyle = 'rgb(255,0,0)';
+    ctx.fillRect(0, 0, 100, 100);
+    ctx.fillStyle = 'rgb(0,255,0)';
+    ctx.beginPath();
+    ctx.rect(0, 0, 100, 100);
+    ctx.rect(25, 25, 50, 50);
+    ctx.clip('nonzero');
+    ctx.beginPath();
+    ctx.fillRect(0, 0, 100, 100);
+    checkResult([0, 255, 0, 255], 5);
+    debug('');
+	
+    debug('Testing evenodd clip');
+    ctx.fillStyle = 'rgb(255,0,0)';
+    ctx.fillRect(0, 0, 100, 100);
+    ctx.fillStyle = 'rgb(0,255,0)';
+    ctx.beginPath();
+    ctx.rect(0, 0, 100, 100);
+    ctx.rect(25, 25, 50, 50);
+    ctx.clip('evenodd');
+    ctx.beginPath();
+    ctx.fillRect(0, 0, 100, 100);
+    checkResult([255, 0, 0, 255], 5);                        
+    debug('');
+
+}
+
+// Run test and allow variation of results.
+prepareTestScenario();
diff --git a/third_party/WebKit/LayoutTests/fast/canvas/script-tests/canvas-fill-rule.js b/third_party/WebKit/LayoutTests/fast/canvas/script-tests/canvas-fill-rule.js
new file mode 100644
index 0000000..482e03a
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/fast/canvas/script-tests/canvas-fill-rule.js
@@ -0,0 +1,66 @@
+description("Series of tests to ensure correct results of the winding rule.");
+
+
+var tmpimg = document.createElement('canvas');
+tmpimg.width = 200;
+tmpimg.height = 200;
+ctx = tmpimg.getContext('2d');
+
+// Create the image for blending test with images.
+var img = document.createElement('canvas');
+img.width = 100;
+img.height = 100;
+var imgCtx = img.getContext('2d');
+
+function pixelDataAtPoint()
+{
+  return ctx.getImageData(50, 50, 1, 1).data;
+}
+
+function checkResult(expectedColors, sigma) {
+    for (var i = 0; i < 4; i++)
+	    shouldBeCloseTo("pixelDataAtPoint()[" + i + "]", expectedColors[i], sigma);
+}
+
+// Execute test.
+function prepareTestScenario() {
+    debug('Testing default fill');
+    ctx.fillStyle = 'rgb(255,0,0)';
+    ctx.beginPath();
+    ctx.fillRect(0, 0, 100, 100);
+    ctx.fillStyle = 'rgb(0,255,0)';
+    ctx.beginPath();
+    ctx.rect(0, 0, 100, 100);
+    ctx.rect(25, 25, 50, 50);
+    ctx.fill();
+    checkResult([0, 255, 0, 255], 5);                        
+    debug('');
+
+    debug('Testing nonzero fill');
+    ctx.fillStyle = 'rgb(255,0,0)';
+    ctx.beginPath();
+    ctx.fillRect(0, 0, 100, 100);
+    ctx.fillStyle = 'rgb(0,255,0)';
+    ctx.beginPath();
+    ctx.rect(0, 0, 100, 100);
+    ctx.rect(25, 25, 50, 50);
+    ctx.fill('nonzero');
+    checkResult([0, 255, 0, 255], 5);
+    debug('');
+	
+    debug('Testing evenodd fill');
+    ctx.fillStyle = 'rgb(255,0,0)';
+    ctx.beginPath();
+    ctx.fillRect(0, 0, 100, 100);
+    ctx.fillStyle = 'rgb(0,255,0)';
+    ctx.beginPath();
+    ctx.rect(0, 0, 100, 100);
+    ctx.rect(25, 25, 50, 50);
+    ctx.fill('evenodd');
+    checkResult([255, 0, 0, 255], 5);                        
+    debug('');
+
+}
+
+// Run test and allow variation of results.
+prepareTestScenario();
diff --git a/third_party/WebKit/LayoutTests/fast/canvas/script-tests/canvas-isPointInPath-winding.js b/third_party/WebKit/LayoutTests/fast/canvas/script-tests/canvas-isPointInPath-winding.js
new file mode 100644
index 0000000..30d0a46
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/fast/canvas/script-tests/canvas-isPointInPath-winding.js
@@ -0,0 +1,40 @@
+description("Series of tests to ensure correct results of the winding rule in isPointInPath.");
+
+
+var tmpimg = document.createElement('canvas');
+tmpimg.width = 200;
+tmpimg.height = 200;
+ctx = tmpimg.getContext('2d');
+
+// Create the image for blending test with images.
+var img = document.createElement('canvas');
+img.width = 100;
+img.height = 100;
+var imgCtx = img.getContext('2d');
+
+// Execute test.
+function prepareTestScenario() {
+    debug('Testing default isPointInPath');
+    ctx.beginPath();
+    ctx.rect(0, 0, 100, 100);
+    ctx.rect(25, 25, 50, 50);
+    shouldBeTrue("ctx.isPointInPath(50, 50)");             
+    debug('');
+
+    debug('Testing nonzero isPointInPath');
+    ctx.beginPath();
+    ctx.rect(0, 0, 100, 100);
+    ctx.rect(25, 25, 50, 50);
+    shouldBeTrue("ctx.isPointInPath(50, 50, 'nonzero')");
+    debug('');
+	
+    debug('Testing evenodd isPointInPath');
+    ctx.beginPath();
+    ctx.rect(0, 0, 100, 100);
+    ctx.rect(25, 25, 50, 50);
+    shouldBeFalse("ctx.isPointInPath(50, 50, 'evenodd')");             
+    debug('');
+}
+
+// Run test and allow variation of results.
+prepareTestScenario();
diff --git a/third_party/WebKit/Source/WebCore/ChangeLog b/third_party/WebKit/Source/WebCore/ChangeLog
index 096998b..706bd39 100644
--- a/third_party/WebKit/Source/WebCore/ChangeLog
+++ b/third_party/WebKit/Source/WebCore/ChangeLog
@@ -1,3 +1,31 @@
+2013-01-21  Rik Cabanier  <cabanier@adobe.com>
+
+        Proposal: Add support for even-odd fill and clip to Canvas
+        https://bugs.webkit.org/show_bug.cgi?id=106188
+
+        Reviewed by Dirk Schulze.
+
+        This patch adds support for an optional winding rule to fill, clip
+        and isPointInPath in canvas 2d. By default, the fill is non-zero but
+        you can now pass in an optional winding rule string ("nonzero" or "evenodd")
+        to make an explicit choice.
+
+        Tests: fast/canvas/canvas-clip-rule.html
+               fast/canvas/canvas-fill-rule.html
+               fast/canvas/canvas-isPointInPath-winding.html
+
+        * html/canvas/CanvasRenderingContext2D.cpp: Change implementation so it sets the windig rule in the context.
+        (WebCore::parseWinding):
+        (WebCore):
+        (WebCore::CanvasRenderingContext2D::fill):
+        (WebCore::CanvasRenderingContext2D::clip):
+        (WebCore::CanvasRenderingContext2D::isPointInPath):
+        * html/canvas/CanvasRenderingContext2D.h: 
+        (CanvasRenderingContext2D):
+        * html/canvas/CanvasRenderingContext2D.idl: Change the idl so the new API is exposed to JavaScript.
+        * platform/graphics/cg/GraphicsContextCG.cpp: Fixes a bug where the wrong winding rule was set for clipping in Core Graphics.
+        (WebCore::GraphicsContext::clip):
+
 2013-01-21  ChangSeok Oh  <shivamidow@gmail.com>
 
         [GTK][AC] setOpacity doesn't work for GraphicsLayerClutter
diff --git a/third_party/WebKit/Source/WebCore/html/canvas/CanvasRenderingContext2D.cpp b/third_party/WebKit/Source/WebCore/html/canvas/CanvasRenderingContext2D.cpp
index 487ca8c..7098f01 100644
--- a/third_party/WebKit/Source/WebCore/html/canvas/CanvasRenderingContext2D.cpp
+++ b/third_party/WebKit/Source/WebCore/html/canvas/CanvasRenderingContext2D.cpp
@@ -1024,7 +1024,19 @@ static bool isFullCanvasCompositeMode(CompositeOperator op)
     return op == CompositeSourceIn || op == CompositeSourceOut || op == CompositeDestinationIn || op == CompositeDestinationAtop;
 }
 
-void CanvasRenderingContext2D::fill()
+static bool parseWinding(const String& windingRuleString, WindRule& windRule)
+{
+    if (windingRuleString == "nonzero")
+        windRule = RULE_NONZERO;
+    else if (windingRuleString == "evenodd")
+        windRule = RULE_EVENODD;
+    else
+        return false;
+    
+    return true;
+}
+
+void CanvasRenderingContext2D::fill(const String& windingRuleString)
 {
     GraphicsContext* c = drawingContext();
     if (!c)
@@ -1033,6 +1045,12 @@ void CanvasRenderingContext2D::fill()
         return;
 
     if (!m_path.isEmpty()) {
+        WindRule windRule = c->fillRule();
+        WindRule newWindRule = RULE_NONZERO;
+        if (!parseWinding(windingRuleString, newWindRule))
+            return;
+        c->setFillRule(newWindRule);
+
         if (isFullCanvasCompositeMode(state().m_globalComposite)) {
             fullCanvasCompositedFill(m_path);
             didDrawEntireCanvas();
@@ -1044,6 +1062,8 @@ void CanvasRenderingContext2D::fill()
             c->fillPath(m_path);
             didDraw(m_path.fastBoundingRect());
         }
+        
+        c->setFillRule(windRule);
     }
 
 #if ENABLE(DASHBOARD_SUPPORT)
@@ -1072,21 +1092,27 @@ void CanvasRenderingContext2D::stroke()
 #endif
 }
 
-void CanvasRenderingContext2D::clip()
+void CanvasRenderingContext2D::clip(const String& windingRuleString)
 {
     GraphicsContext* c = drawingContext();
     if (!c)
         return;
     if (!state().m_invertibleCTM)
         return;
+
+    WindRule newWindRule = RULE_NONZERO;
+    if (!parseWinding(windingRuleString, newWindRule))
+        return;
+
     realizeSaves();
-    c->canvasClip(m_path);
+    c->canvasClip(m_path, newWindRule);
+    
 #if ENABLE(DASHBOARD_SUPPORT)
     clearPathForDashboardBackwardCompatibilityMode();
 #endif
 }
 
-bool CanvasRenderingContext2D::isPointInPath(const float x, const float y)
+bool CanvasRenderingContext2D::isPointInPath(const float x, const float y, const String& windingRuleString)
 {
     GraphicsContext* c = drawingContext();
     if (!c)
@@ -1099,7 +1125,12 @@ bool CanvasRenderingContext2D::isPointInPath(const float x, const float y)
     FloatPoint transformedPoint = ctm.inverse().mapPoint(point);
     if (!isfinite(transformedPoint.x()) || !isfinite(transformedPoint.y()))
         return false;
-    return m_path.contains(transformedPoint);
+
+    WindRule windRule = RULE_NONZERO;
+    if (!parseWinding(windingRuleString, windRule))
+        return false;
+    
+    return m_path.contains(transformedPoint, windRule);
 }
 
 void CanvasRenderingContext2D::clearRect(float x, float y, float width, float height)
diff --git a/third_party/WebKit/Source/WebCore/html/canvas/CanvasRenderingContext2D.h b/third_party/WebKit/Source/WebCore/html/canvas/CanvasRenderingContext2D.h
index fae86b2..de90d63 100644
--- a/third_party/WebKit/Source/WebCore/html/canvas/CanvasRenderingContext2D.h
+++ b/third_party/WebKit/Source/WebCore/html/canvas/CanvasRenderingContext2D.h
@@ -145,11 +145,11 @@ public:
     void arc(float x, float y, float r, float sa, float ea, bool clockwise, ExceptionCode&);
     void rect(float x, float y, float width, float height);
 
-    void fill();
+    void fill(const String& winding = "nonzero");
     void stroke();
-    void clip();
+    void clip(const String& winding = "nonzero");
 
-    bool isPointInPath(const float x, const float y);
+    bool isPointInPath(const float x, const float y, const String& winding = "nonzero");
 
     void clearRect(float x, float y, float width, float height);
     void fillRect(float x, float y, float width, float height);
diff --git a/third_party/WebKit/Source/WebCore/html/canvas/CanvasRenderingContext2D.idl b/third_party/WebKit/Source/WebCore/html/canvas/CanvasRenderingContext2D.idl
index 6bfc594..dc0747f 100644
--- a/third_party/WebKit/Source/WebCore/html/canvas/CanvasRenderingContext2D.idl
+++ b/third_party/WebKit/Source/WebCore/html/canvas/CanvasRenderingContext2D.idl
@@ -23,6 +23,9 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+// FIXME: we should use CanvasWindingRule once support for WebIDL is completed. (bug #106553)
+enum CanvasWindingRule { "nonzero", "evenodd" };
+
 interface CanvasRenderingContext2D : CanvasRenderingContext {
 
     void save();
@@ -124,11 +127,12 @@ interface CanvasRenderingContext2D : CanvasRenderingContext {
              in [Optional=DefaultIsUndefined] float endAngle,
              in [Optional=DefaultIsUndefined] boolean anticlockwise)
         raises (DOMException);
-    void fill();
+    void fill(in [Optional] DOMString winding);
     void stroke();
-    void clip();
+    void clip(in [Optional] DOMString winding);
     boolean isPointInPath(in [Optional=DefaultIsUndefined] float x,
-                          in [Optional=DefaultIsUndefined] float y);
+                          in [Optional=DefaultIsUndefined] float y,
+                          in [Optional] DOMString winding);
 
     // text
     attribute DOMString font;
diff --git a/third_party/WebKit/Source/WebCore/platform/graphics/cg/GraphicsContextCG.cpp b/third_party/WebKit/Source/WebCore/platform/graphics/cg/GraphicsContextCG.cpp
index 6c67725..e4dc895 100644
--- a/third_party/WebKit/Source/WebCore/platform/graphics/cg/GraphicsContextCG.cpp
+++ b/third_party/WebKit/Source/WebCore/platform/graphics/cg/GraphicsContextCG.cpp
@@ -1331,7 +1331,7 @@ void GraphicsContext::clip(const Path& path, WindRule fillRule)
     else {
         CGContextBeginPath(context);
         CGContextAddPath(context, path.platformPath());
-        if (fillRule == RULE_EVENODD)
+        if (fillRule == RULE_NONZERO)
             CGContextClip(context);
         else
             CGContextEOClip(context);