path ops : make it real

Add an option to SkCanvas to turn on path
ops when combining clips. 

Allow Op() to use one of the input paths
as an output path.

Fix a bug in Op() when the minuend is empty
and the subtrahend is not (for difference).

Change the build to allow core to depend on pathops.
Review URL: https://codereview.chromium.org/14474002

git-svn-id: http://skia.googlecode.com/svn/trunk@8855 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 9 insertions, 0 deletions

diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index 930bdb6fbc..2bf5a54a51 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -381,6 +381,13 @@ public:
         fAllowSoftClip = allow;
     }
 
+    /** EXPERIMENTAL -- only used for testing
+        Set to simplify clip stack using path ops.
+     */
+    void setAllowSimplifyClip(bool allow) {
+        fAllowSimplifyClip = allow;
+    }
+
     /** Modify the current clip with the specified region. Note that unlike
         clipRect() and clipPath() which transform their arguments by the current
         matrix, clipRegion() assumes its argument is already in device
@@ -1064,6 +1071,7 @@ private:
     mutable SkRectCompareType fLocalBoundsCompareType;
     mutable bool              fLocalBoundsCompareTypeDirty;
     bool fAllowSoftClip;
+    bool fAllowSimplifyClip;
 
     const SkRectCompareType& getLocalClipBoundsCompareType() const {
         if (fLocalBoundsCompareTypeDirty) {
@@ -1074,6 +1082,7 @@ private:
     }
     void computeLocalClipBoundsCompareType() const;
 
+
     class AutoValidateClip : ::SkNoncopyable {
     public:
         explicit AutoValidateClip(SkCanvas* canvas) : fCanvas(canvas) {