Fix recursive computation of filter bounds for drop shadow,
morphology, blur.
Because we're computing "backwards" from a clip rect of destination
pixels to be filled to the required source pixels, we should use tail
recursion rather than head recursion in onFilterBounds().
This actually only makes a difference for drop-shadow, where
the computation is non-commutative. Blur and morphology commute, but I
moved them to tail recursion anyway for clarity (so all onFilterBounds
use tail recursion).
BUG=skia:
R=bsalomon@google.com
Author: senorblanco@chromium.org
Review URL: https://codereview.chromium.org/481273005
diff --git a/src/effects/SkBlurImageFilter.cpp b/src/effects/SkBlurImageFilter.cpp
index 71bc811..8787cce 100644
--- a/src/effects/SkBlurImageFilter.cpp
+++ b/src/effects/SkBlurImageFilter.cpp
@@ -253,13 +253,13 @@
bool SkBlurImageFilter::onFilterBounds(const SkIRect& src, const SkMatrix& ctm,
SkIRect* dst) const {
SkIRect bounds = src;
- if (getInput(0) && !getInput(0)->filterBounds(src, ctm, &bounds)) {
- return false;
- }
SkVector sigma = SkVector::Make(fSigma.width(), fSigma.height());
ctm.mapVectors(&sigma, 1);
bounds.outset(SkScalarCeilToInt(SkScalarMul(sigma.x(), SkIntToScalar(3))),
SkScalarCeilToInt(SkScalarMul(sigma.y(), SkIntToScalar(3))));
+ if (getInput(0) && !getInput(0)->filterBounds(bounds, ctm, &bounds)) {
+ return false;
+ }
*dst = bounds;
return true;
}
diff --git a/src/effects/SkDropShadowImageFilter.cpp b/src/effects/SkDropShadowImageFilter.cpp
index f1ebae8..29d685b 100644
--- a/src/effects/SkDropShadowImageFilter.cpp
+++ b/src/effects/SkDropShadowImageFilter.cpp
@@ -121,9 +121,6 @@
bool SkDropShadowImageFilter::onFilterBounds(const SkIRect& src, const SkMatrix& ctm,
SkIRect* dst) const {
SkIRect bounds = src;
- if (getInput(0) && !getInput(0)->filterBounds(src, ctm, &bounds)) {
- return false;
- }
SkVector offsetVec = SkVector::Make(fDx, fDy);
ctm.mapVectors(&offsetVec, 1);
bounds.offset(-SkScalarCeilToInt(offsetVec.x()),
@@ -133,6 +130,9 @@
bounds.outset(SkScalarCeilToInt(SkScalarMul(sigma.x(), SkIntToScalar(3))),
SkScalarCeilToInt(SkScalarMul(sigma.y(), SkIntToScalar(3))));
bounds.join(src);
+ if (getInput(0) && !getInput(0)->filterBounds(bounds, ctm, &bounds)) {
+ return false;
+ }
*dst = bounds;
return true;
}
diff --git a/src/effects/SkMorphologyImageFilter.cpp b/src/effects/SkMorphologyImageFilter.cpp
index eef2a7d..6a6dd4d 100644
--- a/src/effects/SkMorphologyImageFilter.cpp
+++ b/src/effects/SkMorphologyImageFilter.cpp
@@ -248,13 +248,13 @@
bool SkMorphologyImageFilter::onFilterBounds(const SkIRect& src, const SkMatrix& ctm,
SkIRect* dst) const {
SkIRect bounds = src;
- if (getInput(0) && !getInput(0)->filterBounds(src, ctm, &bounds)) {
- return false;
- }
SkVector radius = SkVector::Make(SkIntToScalar(this->radius().width()),
SkIntToScalar(this->radius().height()));
ctm.mapVectors(&radius, 1);
bounds.outset(SkScalarCeilToInt(radius.x()), SkScalarCeilToInt(radius.y()));
+ if (getInput(0) && !getInput(0)->filterBounds(bounds, ctm, &bounds)) {
+ return false;
+ }
*dst = bounds;
return true;
}
diff --git a/tests/ImageFilterTest.cpp b/tests/ImageFilterTest.cpp
index f87f99c..e7e0f84 100644
--- a/tests/ImageFilterTest.cpp
+++ b/tests/ImageFilterTest.cpp
@@ -469,6 +469,50 @@
}
}
+static SkImageFilter* makeBlur(SkImageFilter* input = NULL) {
+ return SkBlurImageFilter::Create(SK_Scalar1, SK_Scalar1, input);
+}
+
+static SkImageFilter* makeDropShadow(SkImageFilter* input = NULL) {
+ return SkDropShadowImageFilter::Create(
+ SkIntToScalar(100), SkIntToScalar(100),
+ SkIntToScalar(10), SkIntToScalar(10),
+ SK_ColorBLUE, input);
+}
+
+DEF_TEST(ImageFilterBlurThenShadowBounds, reporter) {
+ SkAutoTUnref<SkImageFilter> filter1(makeBlur());
+ SkAutoTUnref<SkImageFilter> filter2(makeDropShadow(filter1.get()));
+
+ SkIRect bounds = SkIRect::MakeXYWH(0, 0, 100, 100);
+ SkIRect expectedBounds = SkIRect::MakeXYWH(-133, -133, 236, 236);
+ filter2->filterBounds(bounds, SkMatrix(), &bounds);
+
+ REPORTER_ASSERT(reporter, bounds == expectedBounds);
+}
+
+DEF_TEST(ImageFilterShadowThenBlurBounds, reporter) {
+ SkAutoTUnref<SkImageFilter> filter1(makeDropShadow());
+ SkAutoTUnref<SkImageFilter> filter2(makeBlur(filter1.get()));
+
+ SkIRect bounds = SkIRect::MakeXYWH(0, 0, 100, 100);
+ SkIRect expectedBounds = SkIRect::MakeXYWH(-133, -133, 236, 236);
+ filter2->filterBounds(bounds, SkMatrix(), &bounds);
+
+ REPORTER_ASSERT(reporter, bounds == expectedBounds);
+}
+
+DEF_TEST(ImageFilterDilateThenBlurBounds, reporter) {
+ SkAutoTUnref<SkImageFilter> filter1(SkDilateImageFilter::Create(2, 2));
+ SkAutoTUnref<SkImageFilter> filter2(makeDropShadow(filter1.get()));
+
+ SkIRect bounds = SkIRect::MakeXYWH(0, 0, 100, 100);
+ SkIRect expectedBounds = SkIRect::MakeXYWH(-132, -132, 234, 234);
+ filter2->filterBounds(bounds, SkMatrix(), &bounds);
+
+ REPORTER_ASSERT(reporter, bounds == expectedBounds);
+}
+
static void drawBlurredRect(SkCanvas* canvas) {
SkAutoTUnref<SkImageFilter> filter(SkBlurImageFilter::Create(SkIntToScalar(8), 0));
SkPaint filterPaint;
