Implement support for expanding crop rects in image filters

src/effects/SkDropShadowImageFilter.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 "SkDropShadowImageFilter.h"
 
 #include "SkBitmap.h"
@@ skipping 48 matching lines @@
 }
 
 bool SkDropShadowImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& source, const Context& ctx, SkBitmap* result, SkIPoint* offset) const
 {
     SkBitmap src = source;
     SkIPoint srcOffset = SkIPoint::Make(0, 0);
     if (getInput(0) && !getInput(0)->filterImage(proxy, source, ctx, &src, &srcOffset))
         return false;
 
     SkIRect bounds;
-    src.getBounds(&bounds);
-    bounds.offset(srcOffset);
-    if (!this->applyCropRect(&bounds, ctx.ctm())) {
+    if (!this->applyCropRect(ctx, src, srcOffset, &bounds)) {
         return false;
     }
 
     SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(bounds.width(), bounds.height()));
     if (NULL == device.get()) {
         return false;
     }
     SkCanvas canvas(device.get());
 
     SkVector sigma, localSigma = SkVector::Make(fSigmaX, fSigmaY);
     ctx.ctm().mapVectors(&sigma, &localSigma, 1);
     sigma.fX = SkMaxScalar(0, sigma.fX);
     sigma.fY = SkMaxScalar(0, sigma.fY);
     SkAutoTUnref<SkImageFilter> blurFilter(SkBlurImageFilter::Create(sigma.fX, sigma.fY));
     SkAutoTUnref<SkColorFilter> colorFilter(SkColorFilter::CreateModeFilter(fColor, SkXfermode::kSrcIn_Mode));
     SkPaint paint;
     paint.setImageFilter(blurFilter.get());
     paint.setColorFilter(colorFilter.get());
     paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
     SkVector offsetVec, localOffsetVec = SkVector::Make(fDx, fDy);
     ctx.ctm().mapVectors(&offsetVec, &localOffsetVec, 1);
-    canvas.translate(-SkIntToScalar(bounds.fLeft), -SkIntToScalar(bounds.fTop));
+    canvas.translate(SkIntToScalar(srcOffset.fX - bounds.fLeft),
+                     SkIntToScalar(srcOffset.fY - bounds.fTop));
     canvas.drawBitmap(src, offsetVec.fX, offsetVec.fY, &paint);
     canvas.drawBitmap(src, 0, 0);
     *result = device->accessBitmap(false);
     offset->fX = bounds.fLeft;
     offset->fY = bounds.fTop;
     return true;
 }
 
 void SkDropShadowImageFilter::computeFastBounds(const SkRect& src, SkRect* dst) const {
     if (getInput(0)) {
@@ skipping 20 matching lines @@
     bounds.offset(-SkScalarCeilToInt(offsetVec.x()),
                   -SkScalarCeilToInt(offsetVec.y()));
     SkVector sigma, localSigma = SkVector::Make(fSigmaX, fSigmaY);
     ctm.mapVectors(&sigma, &localSigma, 1);
     bounds.outset(SkScalarCeilToInt(SkScalarMul(sigma.x(), SkIntToScalar(3))),
                   SkScalarCeilToInt(SkScalarMul(sigma.y(), SkIntToScalar(3))));
     bounds.join(src);
     *dst = bounds;
     return true;
 }