add asABlur() to maskfilters, so devices like gpu and pdf can query them.

git-svn-id: http://skia.googlecode.com/svn/trunk@1816 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 22 insertions, 0 deletions

diff --git a/include/core/SkMaskFilter.h b/include/core/SkMaskFilter.h
index 641ad83886..84a8fd0c3a 100644
--- a/include/core/SkMaskFilter.h
+++ b/include/core/SkMaskFilter.h
@@ -72,6 +72,28 @@ public:
 
     virtual void flatten(SkFlattenableWriteBuffer& ) {}
 
+    enum BlurType {
+        kNone_BlurType,    //!< this maskfilter is not a blur
+        kNormal_BlurType,  //!< fuzzy inside and outside
+        kSolid_BlurType,   //!< solid inside, fuzzy outside
+        kOuter_BlurType,   //!< nothing inside, fuzzy outside
+        kInner_BlurType,   //!< fuzzy inside, nothing outside
+    };
+
+    struct BlurInfo {
+        SkScalar fRadius;
+        bool     fIgnoreTransform;
+        bool     fHighQuality;
+    };
+
+    /**
+     *  Optional method for maskfilters that can be described as a blur. If so,
+     *  they return the corresponding BlurType and set the fields in BlurInfo
+     *  (if not null). If they cannot be described as a blur, they return
+     *  kNone_BlurType and ignore the info parameter.
+     */
+    virtual BlurType asABlur(BlurInfo*);
+
 protected:
     // empty for now, but lets get our subclass to remember to init us for the future
     SkMaskFilter(SkFlattenableReadBuffer&) {}