From d4ed326d6f3704995b0e91292bf2c87e9d36bb14 Mon Sep 17 00:00:00 2001 From: Yuqian Li Date: Fri, 6 Jan 2017 16:31:46 -0500 Subject: [PATCH] Improve quad edges' smoothness in non-AA cases MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Previously, non-AA quad edges only have an accuracy about 1/2 pixel (while the AA quad edges have an accuracy about 1/8 pixel). Now, we increase non-AA quad edges' accuracy to 1/8 pixel as well. The difference is very significant for rotating non-AA filled circles. For example, run `./out/Debug/SampleApp --slide GM:fillcircle` with AA turned off (by pressing b). The benchmark added reveals that increasing quad accuracy from 1/2 to 1/8 doesn't affect the performance significantly. The following is the 1/2-accuracy performance versus 1/8-accuracy performance: curr/maxrss loops min median mean max stddev samples config bench 7/17 MB 19 2.43µs 2.57µs 2.81µs 10.5µs 22% 16119 8888 path_fill_big_nonaacircle 7/17 MB 17 1.38µs 1.42µs 1.52µs 13µs 20% 21409 8888 path_fill_small_nonaacircle curr/maxrss loops min median mean max stddev samples config bench 7/17 MB 71 2.52µs 2.59µs 2.79µs 7.67µs 19% 7557 8888 path_fill_big_nonaacircle 7/17 MB 64 1.45µs 1.49µs 1.51µs 2.39µs 5% 12704 8888 path_fill_small_nonaacircle BUG=skia: Change-Id: I3482098aeafcc6f2ec9aa3382977c0dc1b650964 Reviewed-on: https://skia-review.googlesource.com/6699 Reviewed-by: Mike Reed Commit-Queue: Yuqian Li --- bench/PathBench.cpp | 20 ++++++++++++++++++++ src/core/SkEdge.cpp | 15 ++++++++++++--- 2 files changed, 32 insertions(+), 3 deletions(-) diff --git a/bench/PathBench.cpp b/bench/PathBench.cpp index 4ca4401163..449d30558e 100644 --- a/bench/PathBench.cpp +++ b/bench/PathBench.cpp @@ -173,6 +173,23 @@ private: typedef PathBench INHERITED; }; +class NonAACirclePathBench: public CirclePathBench { +public: + NonAACirclePathBench(Flags flags) : INHERITED(flags) {} + + void appendName(SkString* name) override { + name->append("nonaacircle"); + } + + void setupPaint(SkPaint* paint) override { + CirclePathBench::setupPaint(paint); + paint->setAntiAlias(false); + } + +private: + typedef CirclePathBench INHERITED; +}; + // Test max speedup of Analytic AA for concave paths class AAAConcavePathBench : public PathBench { public: @@ -1090,6 +1107,9 @@ DEF_BENCH( return new CirclePathBench(FLAGS01); ) DEF_BENCH( return new CirclePathBench(FLAGS10); ) DEF_BENCH( return new CirclePathBench(FLAGS11); ) +DEF_BENCH( return new NonAACirclePathBench(FLAGS00); ) +DEF_BENCH( return new NonAACirclePathBench(FLAGS10); ) + DEF_BENCH( return new AAAConcavePathBench(FLAGS00); ) DEF_BENCH( return new AAAConcavePathBench(FLAGS10); ) DEF_BENCH( return new AAAConvexPathBench(FLAGS00); ) diff --git a/src/core/SkEdge.cpp b/src/core/SkEdge.cpp index 216604b551..f8e8d98b5d 100644 --- a/src/core/SkEdge.cpp +++ b/src/core/SkEdge.cpp @@ -157,16 +157,22 @@ static inline SkFDot6 cheap_distance(SkFDot6 dx, SkFDot6 dy) return dx; } -static inline int diff_to_shift(SkFDot6 dx, SkFDot6 dy) +static inline int diff_to_shift(SkFDot6 dx, SkFDot6 dy, int shiftAA = 2) { // cheap calc of distance from center of p0-p2 to the center of the curve SkFDot6 dist = cheap_distance(dx, dy); // shift down dist (it is currently in dot6) - // down by 5 should give us 1/2 pixel accuracy (assuming our dist is accurate...) + // down by 3 should give us 1/8 pixel accuracy (assuming our dist is accurate...) // this is chosen by heuristic: make it as big as possible (to minimize segments) // ... but small enough so that our curves still look smooth + // When shift > 0, we're using AA and everything is scaled up so we can + // lower the accuracy. +#ifdef SK_SUPPORT_LEGACY_QUAD_SHIFT dist = (dist + (1 << 4)) >> 5; +#else + dist = (dist + (1 << 4)) >> (3 + shiftAA); +#endif // each subdivision (shift value) cuts this dist (error) by 1/4 return (32 - SkCLZ(dist)) >> 1; @@ -214,7 +220,10 @@ bool SkQuadraticEdge::setQuadraticWithoutUpdate(const SkPoint pts[3], int shift) { SkFDot6 dx = (SkLeftShift(x1, 1) - x0 - x2) >> 2; SkFDot6 dy = (SkLeftShift(y1, 1) - y0 - y2) >> 2; - shift = diff_to_shift(dx, dy); + // This is a little confusing: + // before this line, shift is the scale up factor for AA; + // after this line, shift is the fCurveShift. + shift = diff_to_shift(dx, dy, shift); SkASSERT(shift >= 0); } // need at least 1 subdivision for our bias trick