Explicit tile bounds for SkPictureShader

include/core/SkShader.h

Index: include/core/SkShader.h
diff --git a/include/core/SkShader.h b/include/core/SkShader.h
index e5af40dd7a181295a7433af9373a721e22805579..0c05241682fe4ded4ff2cd3a8655dfab8e03f471 100644
--- a/include/core/SkShader.h
+++ b/include/core/SkShader.h
@@ -428,9 +428,16 @@ public:
      *              FIXME: src cannot be const due to SkCanvas::drawPicture
      *  @param tmx  The tiling mode to use when sampling the bitmap in the x-direction.
      *  @param tmy  The tiling mode to use when sampling the bitmap in the y-direction.
+     *  @param tile The tile rectangle in picture coordinates: this represents the subset
+     *              (or superset) of the picture used when building a tile. It is not
+     *              affected by localMatrix and does not imply scaling (only translation
+     *              and cropping). If null, the tile rect is considered equal to the picture
+     *              bounds.
      *  @return     Returns a new shader object. Note: this function never returns null.
     */
-    static SkShader* CreatePictureShader(SkPicture* src, TileMode tmx, TileMode tmy,
+    static SkShader* CreatePictureShader(SkPicture* src,
+                                         TileMode tmx, TileMode tmy,
+                                         const SkRect* tile,

[reed1, 2014/08/06 13:14:35]

nit: I would not change the parameter order from the previous version per-se. I
was thinking:

Create(pic, tx, ty, localmatrix, tilerect)

with no default args at all.

[f(malita), 2014/08/06 14:56:02]

Done.

                                          const SkMatrix* localMatrix = NULL);
 
     /**