1 files changed, 27 insertions, 0 deletions
diff --git a/include/core/SkDevice.h b/include/core/SkDevice.h
index d9a4fde4c2..46bcf1a105 100644
--- a/include/core/SkDevice.h
+++ b/include/core/SkDevice.h
@@ -155,6 +155,31 @@ public:
     virtual void setMatrixClip(const SkMatrix&, const SkRegion&,
                                const SkClipStack&);
 
+    /**
+     *  Observer interface for listening to the calls to
+     *  SkDevice::setMatrixClip(...).  Users of SkDevice instances should
+     *  implement matrixClipChanged(...) to receive notifications.
+     */
+    class SkMatrixClipObserver : public SkRefCnt {
+    public:
+        virtual void matrixClipChanged(const SkMatrix&, const SkRegion&,
+                                       const SkClipStack&) = 0;
+    };
+
+    /** Assign the clip observer.  Note that an extra reference is added to the
+      * observer, and removed at SkDevice construction, or re-assignment of a
+      * different observer.
+      */
+    void setMatrixClipObserver(SkMatrixClipObserver* observer);
+
+    /** Return the device's associated SkMatrixClipObserver, or NULL.
+      * If non-null is returned, the reference count of the object is not
+      * modified.
+      */
+    SkMatrixClipObserver* getMatrixClipObserver() const {
+        return fMatrixClipObserver;
+    }
+
     /** Called when this device gains focus (i.e becomes the current device
         for drawing).
     */
@@ -281,6 +306,8 @@ private:
     SkIPoint    fOrigin;
     SkMetaData* fMetaData;
 
+    SkMatrixClipObserver* fMatrixClipObserver;
+
     SkDeviceFactory* fCachedDeviceFactory;
 };