Simple GPU based dithering:
If dithering is turned on, apply an effect that filters the pixel through
the following pipeline:
for each channel c:
1. Compute quantized colors [low, high] that c is between
2. Pick high by flipping a coin weighted by (c - low)
R=bsalomon@google.com, egdaniel@google.com, robertphillips@google.com
Author: krajcevski@google.com
Review URL: https://codereview.chromium.org/321253002
diff --git a/bench/GradientBench.cpp b/bench/GradientBench.cpp
index 90d45c8..f3e783e 100644
--- a/bench/GradientBench.cpp
+++ b/bench/GradientBench.cpp
@@ -34,12 +34,15 @@
SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorWHITE, SK_ColorBLACK, // 10 lines, 50 colors
};
+static const SkColor gShallowColors[] = { 0xFF555555, 0xFF444444 };
+
// We have several special-cases depending on the number (and spacing) of colors, so
// try to exercise those here.
static const GradData gGradData[] = {
{ 2, gColors, NULL, "" },
{ 50, gColors, NULL, "_hicolor" }, // many color gradient
{ 3, gColors, NULL, "_3color" },
+ { 2, gShallowColors, NULL, "_shallow" },
};
/// Ignores scale
@@ -200,12 +203,22 @@
class GradientBench : public Benchmark {
SkString fName;
SkShader* fShader;
+ bool fDither;
enum {
W = 400,
H = 400,
kRepeat = 15,
};
public:
+ SkShader* makeShader(GradType gradType, GradData data, SkShader::TileMode tm, float scale) {
+ const SkPoint pts[2] = {
+ { 0, 0 },
+ { SkIntToScalar(W), SkIntToScalar(H) }
+ };
+
+ return gGrads[gradType].fMaker(pts, data, tm, scale);
+ }
+
GradientBench(GradType gradType,
GradData data = gGradData[0],
SkShader::TileMode tm = SkShader::kClamp_TileMode,
@@ -224,15 +237,25 @@
fName.append(data.fName);
- const SkPoint pts[2] = {
- { 0, 0 },
- { SkIntToScalar(W), SkIntToScalar(H) }
- };
-
- fShader = gGrads[gradType].fMaker(pts, data, tm, scale);
+ fDither = false;
+ fShader = this->makeShader(gradType, data, tm, scale);
fGeomType = geomType;
}
+ GradientBench(GradType gradType, GradData data, bool dither) {
+ const char *tmname = tilemodename(SkShader::kClamp_TileMode);
+ fName.printf("gradient_%s_%s", gGrads[gradType].fName, tmname);
+ fName.append(data.fName);
+
+ fDither = dither;
+ if (dither) {
+ fName.appendf("_dither");
+ }
+
+ fShader = this->makeShader(gradType, data, SkShader::kClamp_TileMode, 1.0f);
+ fGeomType = kRect_GeomType;
+ }
+
virtual ~GradientBench() {
fShader->unref();
}
@@ -247,6 +270,9 @@
this->setupPaint(&paint);
paint.setShader(fShader);
+ if (fDither) {
+ paint.setDither(true);
+ }
SkRect r = { 0, 0, SkIntToScalar(W), SkIntToScalar(H) };
for (int i = 0; i < loops * kRepeat; i++) {
@@ -304,6 +330,16 @@
DEF_BENCH( return new GradientBench(kConicalOutZero_GradType, gGradData[1]); )
DEF_BENCH( return new GradientBench(kConicalOutZero_GradType, gGradData[2]); )
+// Dithering
+DEF_BENCH( return new GradientBench(kLinear_GradType, gGradData[3], true); )
+DEF_BENCH( return new GradientBench(kLinear_GradType, gGradData[3], false); )
+DEF_BENCH( return new GradientBench(kRadial_GradType, gGradData[3], true); )
+DEF_BENCH( return new GradientBench(kRadial_GradType, gGradData[3], false); )
+DEF_BENCH( return new GradientBench(kSweep_GradType, gGradData[3], true); )
+DEF_BENCH( return new GradientBench(kSweep_GradType, gGradData[3], false); )
+DEF_BENCH( return new GradientBench(kConical_GradType, gGradData[3], true); )
+DEF_BENCH( return new GradientBench(kConical_GradType, gGradData[3], false); )
+
///////////////////////////////////////////////////////////////////////////////
class Gradient2Bench : public Benchmark {