Patch by Mike Lawther (mikelawther@chromium.org).

The HTML5 canvas client of BlurDrawLooper needs the option to not apply the
canvas transform to the blur offset.

see
http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-elemen...
- "The shadowOffsetX and shadowOffsetY attributes specify the distance that the
shadow will be offset in the positive horizontal and positive vertical distance
respectively. Their values are in coordinate space units. They are not affected
by the current transformation matrix."

This patch is part of fixing
http://code.google.com/p/chromium/issues/detail?id=64647.

Review URL:  http://codereview.appspot.com/3391041/



git-svn-id: http://skia.googlecode.com/svn/trunk@631 2bbb7eff-a529-9590-31e7-b0007b416f81

2 files changed, 26 insertions, 2 deletions

diff --git a/include/effects/SkBlurDrawLooper.h b/include/effects/SkBlurDrawLooper.h
index 028b2ebc8b..6f96ff633d 100644
--- a/include/effects/SkBlurDrawLooper.h
+++ b/include/effects/SkBlurDrawLooper.h
@@ -29,7 +29,19 @@ class SkMaskFilter;
 */
 class SkBlurDrawLooper : public SkDrawLooper {
 public:
-    SkBlurDrawLooper(SkScalar radius, SkScalar dx, SkScalar dy, SkColor color);
+    enum BlurFlags {
+        kNone_BlurFlag = 0x00,
+        /** 
+            The blur layer's dx/dy/radius aren't affected by the canvas 
+            transform.
+        */
+        kIgnoreTransform_BlurFlag = 0x01,
+        /** mask for all blur flags */
+        kAll_BlurFlag = 0x01
+    };
+
+    SkBlurDrawLooper(SkScalar radius, SkScalar dx, SkScalar dy, SkColor color, 
+                     uint32_t flags = kNone_BlurFlag);
     virtual ~SkBlurDrawLooper();
 
     // overrides from SkDrawLooper
@@ -41,6 +53,7 @@ public:
         return SkNEW_ARGS(SkBlurDrawLooper, (buffer));
     }
 
+
 protected:
     SkBlurDrawLooper(SkFlattenableReadBuffer&);
     // overrides from SkFlattenable
@@ -55,6 +68,7 @@ private:
     SkColor         fBlurColor;
     SkColor         fSavedColor;    // remember the original
     int             fSaveCount;
+    uint32_t        fBlurFlags;  
 
     enum State {
         kBeforeEdge,
diff --git a/include/effects/SkBlurMaskFilter.h b/include/effects/SkBlurMaskFilter.h
index b90ea5e49e..0a68f54041 100644
--- a/include/effects/SkBlurMaskFilter.h
+++ b/include/effects/SkBlurMaskFilter.h
@@ -32,12 +32,22 @@ public:
         kBlurStyleCount
     };
 
+    enum BlurFlags {
+        kNone_BlurFlag = 0x00,
+        /** The blur layer's radius is not affected by transforms */
+        kIgnoreTransform_BlurFlag = 0x01,
+        /** mask for all blur flags */
+        kAll_BlurFlag = 0x01
+    };
+
     /** Create a blur maskfilter.
         @param radius   The radius to extend the blur from the original mask. Must be > 0.
         @param style    The BlurStyle to use
+        @param flags    Flags to use - defaults to none
         @return The new blur maskfilter
     */
-    static SkMaskFilter* Create(SkScalar radius, BlurStyle style);
+    static SkMaskFilter* Create(SkScalar radius, BlurStyle style, 
+                                uint32_t flags = kNone_BlurFlag);
 
     /** Create an emboss maskfilter
         @param direction    array of 3 scalars [x, y, z] specifying the direction of the light source