Image filters: implement offsets in GPU path.

src/effects/SkBlurImageFilter.cpp

 /*
  * Copyright 2011 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkBlurImageFilter.h"
 #include "SkColorPriv.h"
@@ skipping 101 matching lines @@
                 sumR += SkGetPackedR32(r);
                 sumG += SkGetPackedG32(r);
                 sumB += SkGetPackedB32(r);
             }
             sptr += srcStride;
             dptr += dstStride;
         }
     }
 }
 
-static void getBox3Params(SkScalar s, int *kernelSize, int* kernelSize3, int *lowOffset, int *highOffset)
+static void getBox3Params(SkScalar s, int *kernelSize, int* kernelSize3, int *lowOffset,
+                          int *highOffset)
 {
     float pi = SkScalarToFloat(SK_ScalarPI);
     int d = static_cast<int>(floorf(SkScalarToFloat(s) * 3.0f * sqrtf(2.0f * pi) / 4.0f + 0.5f));
     *kernelSize = d;
     if (d % 2 == 1) {
         *lowOffset = *highOffset = (d - 1) / 2;
         *kernelSize3 = d;
     } else {
         *highOffset = d / 2;
         *lowOffset = *highOffset - 1;
@@ skipping 52 matching lines @@
         boxBlurX(*dst, &temp, kernelSizeX,  highOffsetX,  lowOffsetX);
         boxBlurX(temp, dst,   kernelSizeX3, highOffsetX, highOffsetX);
     } else if (kernelSizeY > 0) {
         boxBlurY(src,  dst,   kernelSizeY,  lowOffsetY, highOffsetY);
         boxBlurY(*dst, &temp, kernelSizeY,  highOffsetY, lowOffsetY);
         boxBlurY(temp, dst,   kernelSizeY3, highOffsetY, highOffsetY);
     }
     return true;
 }
 
-bool SkBlurImageFilter::filterImageGPU(Proxy* proxy, const SkBitmap& src, SkBitmap* result) {
+bool SkBlurImageFilter::filterImageGPU(Proxy* proxy, const SkBitmap& src, SkBitmap* result,
+                                       SkIPoint* offset) {
 #if SK_SUPPORT_GPU
     SkBitmap input;
-    if (!SkImageFilterUtils::GetInputResultGPU(getInput(0), proxy, src, &input)) {
+    if (!SkImageFilterUtils::GetInputResultGPU(getInput(0), proxy, src, &input, offset)) {
         return false;
     }
     GrTexture* source = input.getTexture();
     SkRect rect;
     src.getBounds(&rect);
     SkAutoTUnref<GrTexture> tex(source->getContext()->gaussianBlur(source, false, rect,
         fSigma.width(), fSigma.height()));
     return SkImageFilterUtils::WrapTexture(tex, src.width(), src.height(), result);
 #else
     SkDEBUGFAIL("Should not call in GPU-less build");
     return false;
 #endif
 }