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/*
* Copyright 2018 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "Test.h"
#include "SkHalf.h"
#include "SkSurface.h"
#include "SkCanvas.h"
DEF_TEST(NonlinearBlending, r) {
// First check our familiar basics with linear F16.
{
auto info = SkImageInfo::Make(1,1, kRGBA_F16_SkColorType, kPremul_SkAlphaType,
SkColorSpace::MakeSRGBLinear());
auto surface = SkSurface::MakeRaster(info);
surface->getCanvas()->clear(0xff808080);
uint64_t pix;
REPORTER_ASSERT(r, surface->readPixels(info, &pix, sizeof(pix),0,0));
// 0x80 in sRGB is ≈ 0.22 linear.
REPORTER_ASSERT(r, SkHalfToFloat(pix & 0xffff) < 0.25f);
}
// Test that we support sRGB-encoded F16. This is somewhat new.
{
auto info = SkImageInfo::Make(1,1, kRGBA_F16_SkColorType, kPremul_SkAlphaType,
SkColorSpace::MakeSRGB());
auto surface = SkSurface::MakeRaster(info);
surface->getCanvas()->clear(0xff808080);
uint64_t pix;
REPORTER_ASSERT(r, surface->readPixels(info, &pix, sizeof(pix),0,0));
// 0x80 sRGB is ≈ 0.501.
REPORTER_ASSERT(r, SkHalfToFloat(pix & 0xffff) >= 0.5f);
}
// Since we're only clear()ing, this should work the same as the last block.
{
auto info = SkImageInfo::Make(1,1, kRGBA_F16_SkColorType, kPremul_SkAlphaType,
SkColorSpace::MakeSRGB()->makeNonlinearBlending());
auto surface = SkSurface::MakeRaster(info);
surface->getCanvas()->clear(0xff808080);
uint64_t pix;
REPORTER_ASSERT(r, surface->readPixels(info, &pix, sizeof(pix),0,0));
// 0x80 sRGB is ≈ 0.501.
REPORTER_ASSERT(r, SkHalfToFloat(pix & 0xffff) >= 0.5f);
}
// This won't work until we actually support color spaces with non-linear blending.
if (0) {
auto info = SkImageInfo::Make(1,1, kRGBA_F16_SkColorType, kPremul_SkAlphaType,
SkColorSpace::MakeSRGB()->makeNonlinearBlending());
auto surface = SkSurface::MakeRaster(info);
surface->getCanvas()->clear(SK_ColorWHITE);
SkPaint p;
p.setColor(0x80000000);
surface->getCanvas()->drawPaint(p);
uint64_t pix;
REPORTER_ASSERT(r, surface->readPixels(info, &pix, sizeof(pix),0,0));
// 0x80 sRGB is ≈ 0.501. A likely failure here is ~0.75, linear blending.
REPORTER_ASSERT(r, SkHalfToFloat(pix & 0xffff) >= 0.45f &&
SkHalfToFloat(pix & 0xffff) <= 0.55f);
}
}
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