Bug 985257 - Add implementation for Path2D constructor that takes an SVG path string. r=roc

content/canvas/src/CanvasRenderingContext2D.cpp

@@ -94,6 +94,7 @@
 #include "nsGlobalWindow.h"
 #include "GLContext.h"
 #include "GLContextProvider.h"
+#include "SVGContentUtils.h"
 
 #undef free // apparently defined by some windows header, clashing with a free()
             // method in SkTypes.h
@@ -4362,6 +4363,18 @@ CanvasPath::Constructor(const GlobalObject& aGlobal, CanvasPath& aCanvasPath, Er
   return path.forget();
 }
 
+already_AddRefed<CanvasPath>
+CanvasPath::Constructor(const GlobalObject& aGlobal, const nsAString& aPathString, ErrorResult& aRv)
+{
+  RefPtr<gfx::Path> tempPath = SVGContentUtils::GetPath(aPathString);
+  if (!tempPath) {
+    return Constructor(aGlobal, aRv);
+  }
+
+  nsRefPtr<CanvasPath> path = new CanvasPath(aGlobal.GetAsSupports(), tempPath->CopyToBuilder());
+  return path.forget();
+}
+
 void
 CanvasPath::ClosePath()
 {

content/canvas/src/CanvasRenderingContext2D.h

@@ -61,6 +61,9 @@ public:
   static already_AddRefed<CanvasPath> Constructor(const GlobalObject& aGlobal,
                                                   CanvasPath& aCanvasPath,
                                                   ErrorResult& rv);
+  static already_AddRefed<CanvasPath> Constructor(const GlobalObject& aGlobal,
+                                                  const nsAString& aPathString,
+                                                  ErrorResult& rv);
 
   void ClosePath();
   void MoveTo(double x, double y);

content/canvas/src/moz.build

@@ -97,6 +97,7 @@ FINAL_LIBRARY = 'gklayout'
 LOCAL_INCLUDES += [
     '/content/base/src',
     '/content/html/content/src',
+    '/content/svg/content/src',
     '/content/xul/content/src',
     '/dom/base',
     '/image/src',

content/canvas/test/test_canvas_path.html

@@ -315,6 +315,23 @@ function test_isPointInStroke_canvas() {
 }
 </script>
 
+<p>Canvas test: test_pathconstructor_canvas</p>
+<canvas id="c7" class="output" width="200" height="100">+
+</canvas>
+<script type="text/javascript">
+
+function test_pathconstructor_canvas() {
+  var c = document.getElementById("c7");
+  var ctx = c.getContext("2d");
+
+  var p = new Path2D("M100,0L200,0L200,100L100,100z");
+  ctx.fillStyle = 'blue';
+  ctx.fill(p);
+  isPixel(ctx, 105, 5, [0, 0, 255, 255], 0);
+  isPixel(ctx, 5, 5, [0, 0, 0, 0], 0);
+}
+</script>
+
 <script>
 
 function runTests() {
@@ -354,6 +371,12 @@ function runTests() {
   throw e;
   ok(false, "unexpected exception thrown in: test_isPointInStroke_canvas");
  }
+ try {
+  test_pathconstructor_canvas();
+ } catch(e) {
+  throw e;
+  ok(false, "unexpected exception thrown in: test_pathconstructor_canvas");
+ }
  SpecialPowers.setBoolPref("canvas.path.enabled", false);
  SimpleTest.finish();
 }

content/svg/content/src/SVGContentUtils.cpp

@@ -20,6 +20,7 @@
 #include "nsContentUtils.h"
 #include "mozilla/gfx/2D.h"
 #include "gfx2DGlue.h"
+#include "nsSVGPathDataParser.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
@@ -584,3 +585,15 @@ SVGContentUtils::CoordToFloat(nsPresContext *aPresContext,
     return 0.0f;
   }
 }
+
+RefPtr<gfx::Path>
+SVGContentUtils::GetPath(const nsAString& aPathString)
+{
+  SVGPathData pathData;
+  nsSVGPathDataParser parser(aPathString, &pathData);
+  if (!parser.Parse()) {
+    return NULL;
+  }
+
+  return pathData.BuildPath(FillRule::FILL_WINDING, NS_STYLE_STROKE_LINECAP_BUTT, 1);
+}

content/svg/content/src/SVGContentUtils.h

@@ -14,6 +14,7 @@
 #include "mozilla/RangedPtr.h"
 #include "nsError.h"
 #include "nsStringFwd.h"
+#include "gfx2DGlue.h"
 
 class nsIContent;
 class nsIDocument;
@@ -243,6 +244,13 @@ public:
   static float CoordToFloat(nsPresContext *aPresContext,
                             nsSVGElement *aContent,
                             const nsStyleCoord &aCoord);
+  /**
+   * Parse the SVG path string
+   * Returns a path
+   * string formatted as an SVG path
+   */
+  static mozilla::RefPtr<mozilla::gfx::Path>
+  GetPath(const nsAString& aPathString);
 };
 
 #endif

dom/webidl/CanvasRenderingContext2D.webidl

@@ -316,7 +316,8 @@ interface TextMetrics {
 
 [Pref="canvas.path.enabled",
  Constructor,
- Constructor(Path2D other)]
+ Constructor(Path2D other),
+ Constructor(DOMString pathString)]
 interface Path2D
 {};
 Path2D implements CanvasPathMethods;