Fix recursive computation of filter bounds for drop shadow,

morphology, blur.

[Reland with fixed tests.]

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
This commit is contained in:
senorblanco 2014-08-25 12:46:58 -07:00 committed by Commit bot
parent 5387c83f81
commit 1150a6d151
4 changed files with 53 additions and 9 deletions

View File

@ -253,13 +253,13 @@ void SkBlurImageFilter::computeFastBounds(const SkRect& src, SkRect* dst) const
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;
}

View File

@ -121,9 +121,6 @@ void SkDropShadowImageFilter::computeFastBounds(const SkRect& src, SkRect* dst)
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 @@ bool SkDropShadowImageFilter::onFilterBounds(const SkIRect& src, const SkMatrix&
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;
}

View File

@ -248,13 +248,13 @@ void SkMorphologyImageFilter::computeFastBounds(const SkRect& src, SkRect* dst)
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;
}

View File

@ -469,6 +469,50 @@ DEF_TEST(ImageFilterDrawMatrixBBH, reporter) {
}
}
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::I(), &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::I(), &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::I(), &bounds);
REPORTER_ASSERT(reporter, bounds == expectedBounds);
}
static void drawBlurredRect(SkCanvas* canvas) {
SkAutoTUnref<SkImageFilter> filter(SkBlurImageFilter::Create(SkIntToScalar(8), 0));
SkPaint filterPaint;