Image filters: implement offsets in GPU path.

src/effects/SkDisplacementMapEffect.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 "SkDisplacementMapEffect.h"
 #include "SkFlattenableBuffers.h"
 #include "SkUnPreMultiply.h"
@@ skipping 257 matching lines @@
 
     GrTextureAccess             fDisplacementAccess;
     GrTextureAccess             fColorAccess;
     SkDisplacementMapEffect::ChannelSelectorType fXChannelSelector;
     SkDisplacementMapEffect::ChannelSelectorType fYChannelSelector;
     SkScalar fScale;
 
     typedef GrEffect INHERITED;
 };
 
-bool SkDisplacementMapEffect::filterImageGPU(Proxy* proxy, const SkBitmap& src, SkBitmap* result) {
+bool SkDisplacementMapEffect::filterImageGPU(Proxy* proxy, const SkBitmap& src, SkBitmap* result,
+                                             SkIPoint* offset) {
     SkBitmap colorBM;
-    if (!SkImageFilterUtils::GetInputResultGPU(getColorInput(), proxy, src, &colorBM)) {
+    SkIPoint colorOffset = SkIPoint::Make(0, 0);
+    if (!SkImageFilterUtils::GetInputResultGPU(getColorInput(), proxy, src, &colorBM,
+                                               &colorOffset)) {
         return false;
     }
     GrTexture* color = colorBM.getTexture();
     SkBitmap displacementBM;
-    if (!SkImageFilterUtils::GetInputResultGPU(getDisplacementInput(), proxy, src, &displacementBM)) {
+    SkIPoint displacementOffset = SkIPoint::Make(0, 0);
+    if (!SkImageFilterUtils::GetInputResultGPU(getDisplacementInput(), proxy, src, &displacementBM,
+                                               &displacementOffset)) {
         return false;
     }
     GrTexture* displacement = displacementBM.getTexture();
     GrContext* context = color->getContext();
 
     GrTextureDesc desc;
     desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
     desc.fWidth = src.width();
     desc.fHeight = src.height();
     desc.fConfig = kSkia8888_GrPixelConfig;
 
     GrAutoScratchTexture ast(context, desc);
     SkAutoTUnref<GrTexture> dst(ast.detach());
 
     GrContext::AutoRenderTarget art(context, dst->asRenderTarget());
 
     GrPaint paint;
     paint.colorStage(0)->setEffect(
         GrDisplacementMapEffect::Create(fXChannelSelector,
                                         fYChannelSelector,
                                         fScale,
                                         displacement,
                                         color))->unref();
     SkRect srcRect;
     src.getBounds(&srcRect);
-    context->drawRect(paint, srcRect);
+    SkRect dstRect = srcRect;
+    dstRect.offset(SkIntToScalar(colorOffset.fX), SkIntToScalar(colorOffset.fY));
+    context->drawRectToRect(paint, srcRect, dstRect);
     return SkImageFilterUtils::WrapTexture(dst, src.width(), src.height(), result);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 GrDisplacementMapEffect::GrDisplacementMapEffect(
                              SkDisplacementMapEffect::ChannelSelectorType xChannelSelector,
                              SkDisplacementMapEffect::ChannelSelectorType yChannelSelector,
                              SkScalar scale,
                              GrTexture* displacement,
@@ skipping 203 matching lines @@
                                                   colorTex);
 
     colorKey <<= GrGLEffectMatrix::kKeyBits;
     EffectKey xKey = displacementMap.xChannelSelector() << (2 * GrGLEffectMatrix::kKeyBits);
     EffectKey yKey = displacementMap.yChannelSelector() << (2 * GrGLEffectMatrix::kKeyBits +
                                                             SkDisplacementMapEffect::kKeyBits);
 
     return xKey | yKey | displKey | colorKey;
 }
 #endif