change offset to xy for pixelref subsetting

include/core/SkBitmap.h

Index: include/core/SkBitmap.h
diff --git a/include/core/SkBitmap.h b/include/core/SkBitmap.h
index 2b900bef341ddbc678714c758b8c7d81e9abec0c..e53593805666e1ece3ebf6e0743de34938e8d343 100644
--- a/include/core/SkBitmap.h
+++ b/include/core/SkBitmap.h
@@ -353,12 +353,21 @@ public:
     /** Return the offset into the pixelref, if any. Will return 0 if there is
         no pixelref installed.
     */
-    size_t pixelRefOffset() const { return fPixelRefOffset; }
+//    size_t pixelRefOffset() const { return fPixelRefOffset; }

[scroggo, 2014/01/07 22:11:33]

Any reason not to delete this outright?

[reed1, 2014/01/07 22:37:59]

Done.

+
+    SkIPoint pixelRefOrigin() const { return fPixelRefOrigin; }
+
     /** Assign a pixelref and optional offset. Pixelrefs are reference counted,
         so the existing one (if any) will be unref'd and the new one will be
         ref'd.
     */
-    SkPixelRef* setPixelRef(SkPixelRef* pr, size_t offset = 0);
+    SkPixelRef* setPixelRef(SkPixelRef* pr, int dx, int dy);
+    SkPixelRef* setPixelRef(SkPixelRef* pr) {
+        return this->setPixelRef(pr, 0, 0);
+    }
+    SkPixelRef* setPixelRef(SkPixelRef* pr, const SkIPoint& origin) {
+        return this->setPixelRef(pr, origin.fX, origin.fY);
+    }
 
     /** Call this to ensure that the bitmap points to the current pixel address
         in the pixelref. Balance it with a call to unlockPixels(). These calls
@@ -665,13 +674,14 @@ private:
     mutable MipMap* fMipMap;
 
     mutable SkPixelRef* fPixelRef;
-    mutable size_t      fPixelRefOffset;
     mutable int         fPixelLockCount;
     // either user-specified (in which case it is not treated as mutable)
     // or a cache of the returned value from fPixelRef->lockPixels()
     mutable void*       fPixels;
     mutable SkColorTable* fColorTable;    // only meaningful for kIndex8
 
+    SkIPoint    fPixelRefOrigin;

[scroggo, 2014/01/07 22:11:33]

Why was the old one mutable, and this one not? (My guess is that it shouldn't be
mutable, but it'd be nice to know why it used to be.)

+
     enum Flags {
         kImageIsOpaque_Flag     = 0x01,
         kImageIsVolatile_Flag   = 0x02,