Make SkImageFilter crop rects relative to the primitive origin, instead of relative to their parent

gm/offsetimagefilter.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 #include "SkOffsetImageFilter.h"
 #include "SkBitmapSource.h"
@@ skipping 52 matching lines @@
         }
     }
 
     virtual SkISize onISize() {
         return make_isize(WIDTH, HEIGHT);
     }
 
     void drawClippedBitmap(SkCanvas* canvas, const SkBitmap& bitmap, const SkPaint& paint,
                            SkScalar x, SkScalar y) {
         canvas->save();
-        canvas->clipRect(SkRect::MakeXYWH(x, y,
+        canvas->translate(x, y);
+        canvas->clipRect(SkRect::MakeXYWH(0, 0,
             SkIntToScalar(bitmap.width()), SkIntToScalar(bitmap.height())));
-        canvas->drawBitmap(bitmap, x, y, &paint);
+        canvas->drawBitmap(bitmap, 0, 0, &paint);
         canvas->restore();
     }
 
     virtual void onDraw(SkCanvas* canvas) {
         if (!fInitialized) {
             make_bitmap();
             make_checkerboard();
             fInitialized = true;
         }
         canvas->clear(0x00000000);
         SkPaint paint;
 
         int x = 0, y = 0;
         for (size_t i = 0; i < 4; i++) {
             SkBitmap* bitmap = (i & 0x01) ? &fCheckerboard : &fBitmap;
-            SkIRect cropRect = SkIRect::MakeXYWH(x + i * 12,
-                                                 y + i * 8,
+            SkIRect cropRect = SkIRect::MakeXYWH(i * 12,
+                                                 i * 8,
                                                  bitmap->width() - i * 8,
                                                  bitmap->height() - i * 12);
             SkImageFilter::CropRect rect(SkRect::Make(cropRect));
             SkAutoTUnref<SkImageFilter> tileInput(SkNEW_ARGS(SkBitmapSource, (*bitmap)));
             SkScalar dx = SkIntToScalar(i*5);
             SkScalar dy = SkIntToScalar(i*10);
             SkAutoTUnref<SkImageFilter> filter(SkNEW_ARGS(
                 SkOffsetImageFilter, (dx, dy, tileInput, &rect)));
             paint.setImageFilter(filter);
             drawClippedBitmap(canvas, *bitmap, paint, SkIntToScalar(x), SkIntToScalar(y));
             x += bitmap->width() + MARGIN;
             if (x + bitmap->width() > WIDTH) {
                 x = 0;
                 y += bitmap->height() + MARGIN;
             }
         }
     }
 private:
     typedef GM INHERITED;
     SkBitmap fBitmap, fCheckerboard;
     bool fInitialized;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static GM* MyFactory(void*) { return new OffsetImageFilterGM; }
 static GMRegistry reg(MyFactory);
 
 }