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..e3e43de638332efb7a83db838a5e096f2df136a9 100644
--- a/include/core/SkShader.h
+++ b/include/core/SkShader.h
@@ -428,10 +428,13 @@ 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 rect in picture coordinates. 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,
-                                         const SkMatrix* localMatrix = NULL);
+                                         const SkMatrix* localMatrix = NULL,
+                                         const SkRect* tile = NULL);

[reed1, 2014/08/05 15:51:25]

Some documentation questions:

Does adding a tile rect affect the translation of the contents? i.e. in what
order are localMatrix and tileRect applied?

[f(malita), 2014/08/05 16:39:57]

Yes, the tile offset is in "picture-space" (not affected by localMatrix) and
translates the contents. I'll update the documentation.

 
     /**
      *  Return a shader that will apply the specified localMatrix to the proxy shader.