Implement crop rect for SkImageFilter

src/gpu/SkGpuDevice.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGpuDevice.h"
 
 #include "effects/GrTextureDomainEffect.h"
@@ skipping 1369 matching lines @@
     }
 
     int w = bitmap.width();
     int h = bitmap.height();
 
     GrTexture* texture;
     // draw sprite uses the default texture params
     SkAutoCachedTexture act(this, bitmap, NULL, &texture);
 
     SkImageFilter* filter = paint.getImageFilter();
-    SkIPoint offset = SkIPoint::Make(0, 0);
+    SkIPoint offset = SkIPoint::Make(left, top);
     // This bitmap will own the filtered result as a texture.
     SkBitmap filteredBitmap;
 
     if (NULL != filter) {
         if (filter_texture(this, fContext, texture, filter, w, h, &filteredBitmap, &offset)) {
             texture = (GrTexture*) filteredBitmap.getTexture();
             w = filteredBitmap.width();
             h = filteredBitmap.height();
         }
     }
 
     GrPaint grPaint;
     grPaint.addColorTextureEffect(texture, SkMatrix::I());
 
     if(!skPaint2GrPaintNoShader(this, paint, true, false, &grPaint)) {
         return;
     }
 
     fContext->drawRectToRect(grPaint,
-                             SkRect::MakeXYWH(SkIntToScalar(left),
-                                              SkIntToScalar(top),
+                             SkRect::MakeXYWH(SkIntToScalar(offset.fX),
+                                              SkIntToScalar(offset.fY),
                                               SkIntToScalar(w),
                                               SkIntToScalar(h)),
-                             SkRect::MakeXYWH(SkIntToScalar(offset.fX),
-                                              SkIntToScalar(offset.fY),
+                             SkRect::MakeXYWH(0,
+                                              0,
                                               SK_Scalar1 * w / texture->width(),
                                               SK_Scalar1 * h / texture->height()));
 }
 
 void SkGpuDevice::drawBitmapRect(const SkDraw& draw, const SkBitmap& bitmap,
                                  const SkRect* src, const SkRect& dst,
                                  const SkPaint& paint) {
     SkMatrix    matrix;
     SkRect      bitmapBounds, tmpSrc;
 
@@ skipping 337 matching lines @@
                          GrTexture* texture,
                          bool needClear)
     : SkDevice(make_bitmap(context, texture->asRenderTarget())) {
 
     GrAssert(texture && texture->asRenderTarget());
     // This constructor is called from onCreateCompatibleDevice. It has locked the RT in the texture
     // cache. We pass true for the third argument so that it will get unlocked.
     this->initFromRenderTarget(context, texture->asRenderTarget(), true);
     fNeedClear = needClear;
 }