Implement support for expanding crop rects in image filters

src/effects/SkDisplacementMapEffect.cpp

Index: src/effects/SkDisplacementMapEffect.cpp
diff --git a/src/effects/SkDisplacementMapEffect.cpp b/src/effects/SkDisplacementMapEffect.cpp
index a1c18c647ef6c168b222ead68bf321a872e8cdee..4b26a5f846083f55de3e6707fcc9adf700ed9e7f 100644
--- a/src/effects/SkDisplacementMapEffect.cpp
+++ b/src/effects/SkDisplacementMapEffect.cpp
@@ -209,26 +209,23 @@ bool SkDisplacementMapEffect::onFilterImage(Proxy* proxy,
         (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()) {
@@ -254,14 +251,18 @@ void SkDisplacementMapEffect::computeFastBounds(const SkRect& src, SkRect* 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;
 }
 
@@ -356,7 +357,6 @@ bool SkDisplacementMapEffect::filterImageGPU(Proxy* proxy, const SkBitmap& src,
                                                                &colorOffset)) {
         return false;
     }
-    GrTexture* color = colorBM.getTexture();
     SkBitmap displacementBM = src;
     SkIPoint displacementOffset = SkIPoint::Make(0, 0);
     if (getDisplacementInput() &&
@@ -364,6 +364,21 @@ bool SkDisplacementMapEffect::filterImageGPU(Proxy* proxy, const SkBitmap& src,
                                                    &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();
 
@@ -380,21 +395,6 @@ bool SkDisplacementMapEffect::filterImageGPU(Proxy* proxy, const SkBitmap& src,
 
     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);