skia2/tests/NonlinearBlendingTest.cpp
Mike Klein ce4cf72e34 non-linear blending first steps
Code:
  - Add a non-linear blending bit and makeNonlinearBlending()
    to SkColorSpace
  - remove enough F16=linear checks to make it possible to
    create surfaces and encode pngs with nonlinear F16

Testing:
  - add "esrgb" software config to DM, run it
  - add "srgbnl" software config, run it
  - deemphasize importance of "srgb" config on bots
  - update unit tests to reflect relaxed F16 constraints
  - add a new unit test file with _really_ basic tests,
    and a new unit test that's not working yet

Bug: skia:7942

Change-Id: I8ac042bdf9f3d791765393b68fd9256375184d83
Reviewed-on: https://skia-review.googlesource.com/127325
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
2018-05-10 18:26:22 +00:00

77 lines
2.7 KiB
C++

/*
* 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);
}
}