AuroraMiddleware/skia2
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

fix too-dark 565 (really, all legacy) gradients

Browse Source 
This CL reverts legacy destinations back to lerping bytes.
Lerping linear is only the correct behavior for gradients
drawing into colorspace-aware destinations.

As written we're lerping between de-sRGB'd colors but never
transforming the outputs back.  That leaves us in a weird
halfway-right-is-worse-than-wrong spot for legacy.

Change-Id: I79b85552b6913649afd2414205cf57108a8b93c6
Reviewed-on: https://skia-review.googlesource.com/13064
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Florin Malita <fmalita@chromium.org>
This commit is contained in:
Mike Klein 2017-04-10 12:51:43 -04:00 committed by Skia Commit-Bot
parent c8e924c236
commit 95ddf137b2
1 changed files with 14 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
src/effects/gradients/SkLinearGradient.cpp
View File

@ -91,7 +91,7 @@ SkShader::Context* SkLinearGradient::onMakeContext(
// * optional premul
//
bool SkLinearGradient::onAppendStages(SkRasterPipeline* p,
SkColorSpace* cs,
SkColorSpace* dstCS,
SkArenaAlloc* alloc,
const SkMatrix& ctm,
const SkPaint& paint,
@ -128,10 +128,11 @@ bool SkLinearGradient::onAppendStages(SkRasterPipeline* p,
auto* limit = alloc->make<float>(1.0f);
const bool premulGrad = fGradFlags & SkGradientShader::kInterpolateColorsInPremul_Flag;
auto prepareColor = [premulGrad, cs, this](SkColor4f c) {
auto correctedColor = to_colorspace(c, fColorSpace.get(), cs);
return premulGrad ? correctedColor.premul()
: SkPM4f::From4f(Sk4f::Load(&correctedColor));
auto prepareColor = [premulGrad, dstCS, this](int i) {
SkColor4f c = dstCS ? to_colorspace(fOrigColors4f[i], fColorSpace.get(), dstCS)
: SkColor4f_from_SkColor(fOrigColors[i], nullptr);
return premulGrad ? c.premul()
: SkPM4f::From4f(Sk4f::Load(&c));
};
// The two-stop case with stops at 0 and 1.
@ -142,8 +143,8 @@ bool SkLinearGradient::onAppendStages(SkRasterPipeline* p,
case kRepeat_TileMode: p->append(SkRasterPipeline::repeat_x, limit); break;
}
const SkPM4f c_l = prepareColor(fOrigColors4f[0]),
c_r = prepareColor(fOrigColors4f[1]);
const SkPM4f c_l = prepareColor(0),
c_r = prepareColor(1);
// See F and B below.
auto* f_and_b = alloc->makeArrayDefault<SkPM4f>(2);
@ -164,7 +165,7 @@ bool SkLinearGradient::onAppendStages(SkRasterPipeline* p,
struct Ctx { size_t n; Stop* stops; SkPM4f start; };
auto* ctx = alloc->make<Ctx>();
ctx->start = prepareColor(fOrigColors4f[0]);
ctx->start = prepareColor(0);
// For each stop we calculate a bias B and a scale factor F, such that
// for any t between stops n and n+1, the color we want is B[n] + F[n]*t.
@ -187,7 +188,7 @@ bool SkLinearGradient::onAppendStages(SkRasterPipeline* p,
for (int i = 0; i < fColorCount - 1; i++) {
// Use multiply instead of accumulating error using repeated addition.
float t_r = (i + 1) * dt;
SkPM4f c_r = prepareColor(fOrigColors4f[i + 1]);
SkPM4f c_r = prepareColor(i + 1);
init_stop(t_l, t_r, c_l, c_r, &stopsArray[i]);
t_l = t_r;
@ -197,7 +198,7 @@ bool SkLinearGradient::onAppendStages(SkRasterPipeline* p,
// Force the last stop.
stopsArray[fColorCount - 1].t = 1;
stopsArray[fColorCount - 1].f = SkPM4f::From4f(Sk4f{0});
stopsArray[fColorCount - 1].b = prepareColor(fOrigColors4f[fColorCount - 1]);
stopsArray[fColorCount - 1].b = prepareColor(fColorCount - 1);
ctx->n = fColorCount;
ctx->stops = stopsArray;
@ -224,11 +225,11 @@ bool SkLinearGradient::onAppendStages(SkRasterPipeline* p,
size_t stopCount = 0;
float t_l = fOrigPos[firstStop];
SkPM4f c_l = prepareColor(fOrigColors4f[firstStop]);
SkPM4f c_l = prepareColor(firstStop);
// N.B. lastStop is the index of the last stop, not one after.
for (int i = firstStop; i < lastStop; i++) {
float t_r = fOrigPos[i + 1];
SkPM4f c_r = prepareColor(fOrigColors4f[i + 1]);
SkPM4f c_r = prepareColor(i + 1);
if (t_l < t_r) {
init_stop(t_l, t_r, c_l, c_r, &stopsArray[stopCount]);
stopCount += 1;
@ -239,7 +240,7 @@ bool SkLinearGradient::onAppendStages(SkRasterPipeline* p,
stopsArray[stopCount].t = fOrigPos[lastStop];
stopsArray[stopCount].f = SkPM4f::From4f(Sk4f{0});
stopsArray[stopCount].b = prepareColor(fOrigColors4f[lastStop]);
stopsArray[stopCount].b = prepareColor(lastStop);
stopCount += 1;
ctx->n = stopCount;