Implement support for expanding crop rects in image filters

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 "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
@@ skipping 191 matching lines @@
     const SkImageFilter* displInput = getDisplacementInput();
     SkIPoint colorOffset = SkIPoint::Make(0, 0), displOffset = SkIPoint::Make(0, 0);
     if ((colorInput && !colorInput->filterImage(proxy, src, ctx, &color, &colorOffset)) ||
         (displInput && !displInput->filterImage(proxy, src, ctx, &displ, &displOffset))) {
         return false;
     }
     if ((displ.colorType() != kPMColor_SkColorType) ||
         (color.colorType() != kPMColor_SkColorType)) {
         return false;
     }
-
-    SkAutoLockPixels alp_displacement(displ), alp_color(color);
-    if (!displ.getPixels() || !color.getPixels()) {
-        return false;
-    }
     SkIRect bounds;
-    color.getBounds(&bounds);
-    bounds.offset(colorOffset);
-    if (!this->applyCropRect(&bounds, ctx.ctm())) {
+    // Since computeDisplacement does bounds checking on color pixel access, we don't need to pad
+    // the color bitmap to bounds here.
+    if (!this->applyCropRect(ctx, color, colorOffset, &bounds)) {
         return false;
     }
     SkIRect displBounds;
-    displ.getBounds(&displBounds);
-    displBounds.offset(displOffset);
-    if (!this->applyCropRect(&displBounds, ctx.ctm())) {
+    if (!this->applyCropRect(ctx, proxy, displ, &displOffset, &displBounds, &displ)) {
         return false;
     }
     if (!bounds.intersect(displBounds)) {
         return false;
     }
+    SkAutoLockPixels alp_displacement(displ), alp_color(color);
+    if (!displ.getPixels() || !color.getPixels()) {
+        return false;
+    }
 
     dst->setConfig(color.config(), bounds.width(), bounds.height());
     if (!dst->allocPixels()) {
         return false;
     }
 
     SkVector scale = SkVector::Make(fScale, fScale);
     ctx.ctm().mapVectors(&scale, 1);
     SkIRect colorBounds = bounds;
     colorBounds.offset(-colorOffset);
 
     computeDisplacement(fXChannelSelector, fYChannelSelector, scale, dst,
                         &displ, colorOffset - displOffset, &color, colorBounds);
 
     offset->fX = bounds.left();
     offset->fY = bounds.top();
     return true;
 }
 
 void SkDisplacementMapEffect::computeFastBounds(const SkRect& src, SkRect* dst) const {
     if (getColorInput()) {
         getColorInput()->computeFastBounds(src, dst);
     } else {
         *dst = src;
     }
+    dst->outset(fScale * SK_ScalarHalf, fScale * SK_ScalarHalf);
 }
 
 bool SkDisplacementMapEffect::onFilterBounds(const SkIRect& src, const SkMatrix& ctm,
                                    SkIRect* dst) const {
-    if (getColorInput()) {
-        return getColorInput()->filterBounds(src, ctm, dst);
+    SkIRect bounds = src;
+    if (getColorInput() && !getColorInput()->filterBounds(src, ctm, &bounds)) {
+        return false;
     }
-    *dst = src;
+    bounds.outset(SkScalarCeilToInt(fScale * SK_ScalarHalf),
+                  SkScalarCeilToInt(fScale * SK_ScalarHalf));
+    *dst = bounds;
     return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 #if SK_SUPPORT_GPU
 class GrGLDisplacementMapEffect : public GrGLEffect {
 public:
     GrGLDisplacementMapEffect(const GrBackendEffectFactory& factory,
                               const GrDrawEffect& drawEffect);
@@ skipping 74 matching lines @@
 };
 
 bool SkDisplacementMapEffect::filterImageGPU(Proxy* proxy, const SkBitmap& src, const Context& ctx,
                                              SkBitmap* result, SkIPoint* offset) const {
     SkBitmap colorBM = src;
     SkIPoint colorOffset = SkIPoint::Make(0, 0);
     if (getColorInput() && !getColorInput()->getInputResultGPU(proxy, src, ctx, &colorBM,
                                                                &colorOffset)) {
         return false;
     }
-    GrTexture* color = colorBM.getTexture();
     SkBitmap displacementBM = src;
     SkIPoint displacementOffset = SkIPoint::Make(0, 0);
     if (getDisplacementInput() &&
         !getDisplacementInput()->getInputResultGPU(proxy, src, ctx, &displacementBM,
                                                    &displacementOffset)) {
         return false;
     }
+    SkIRect bounds;
+    // Since GrDisplacementMapEffect does bounds checking on color pixel access, we don't need to
+    // pad the color bitmap to bounds here.
+    if (!this->applyCropRect(ctx, colorBM, colorOffset, &bounds)) {
+        return false;
+    }
+    SkIRect displBounds;
+    if (!this->applyCropRect(ctx, proxy, displacementBM,
+                             &displacementOffset, &displBounds, &displacementBM)) {
+        return false;
+    }
+    if (!bounds.intersect(displBounds)) {
+        return false;
+    }
+    GrTexture* color = colorBM.getTexture();
     GrTexture* displacement = displacementBM.getTexture();
     GrContext* context = color->getContext();
 
     GrTextureDesc desc;
     desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
     desc.fWidth = colorBM.width();
     desc.fHeight = colorBM.height();
     desc.fConfig = kSkia8888_GrPixelConfig;
 
     GrAutoScratchTexture ast(context, desc);
     SkAutoTUnref<GrTexture> dst(ast.detach());
 
     GrContext::AutoRenderTarget art(context, dst->asRenderTarget());
 
     SkVector scale = SkVector::Make(fScale, fScale);
     ctx.ctm().mapVectors(&scale, 1);
-    SkIRect bounds;
-    colorBM.getBounds(&bounds);
-    bounds.offset(colorOffset);
-    if (!this->applyCropRect(&bounds, ctx.ctm())) {
-        return false;
-    }
-    SkIRect displBounds;
-    displacementBM.getBounds(&displBounds);
-    displBounds.offset(displacementOffset);
-    if (!this->applyCropRect(&displBounds, ctx.ctm())) {
-        return false;
-    }
-    if (!bounds.intersect(displBounds)) {
-        return false;
-    }
 
     GrPaint paint;
     SkMatrix offsetMatrix = GrEffect::MakeDivByTextureWHMatrix(displacement);
     offsetMatrix.preTranslate(SkIntToScalar(colorOffset.fX - displacementOffset.fX),
                               SkIntToScalar(colorOffset.fY - displacementOffset.fY));
 
     paint.addColorEffect(
         GrDisplacementMapEffect::Create(fXChannelSelector,
                                         fYChannelSelector,
                                         scale,
@@ skipping 194 matching lines @@
                                                         const GrGLCaps&) {
     const GrDisplacementMapEffect& displacementMap =
         drawEffect.castEffect<GrDisplacementMapEffect>();
 
     EffectKey xKey = displacementMap.xChannelSelector();
     EffectKey yKey = displacementMap.yChannelSelector() << kChannelSelectorKeyBits;
 
     return xKey | yKey;
 }
 #endif