ac41bac40f
This makes them a little easier to use outside SkColorXform code. I've added some notes about how best to use them and their eccentricities, and added a test. Ultimately any software sRGB <-> linear conversion should funnel somehow through here. BUG=skia: GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2128893002 CQ_EXTRA_TRYBOTS=client.skia.android:Test-Android-GCC-Nexus5-CPU-NEON-Arm7-Release-Trybot;client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot Committed: https://skia.googlesource.com/skia/+/45e58c8807179638980aae8503573b950b844e4c Review-Url: https://codereview.chromium.org/2128893002
42 lines
1.1 KiB
C++
42 lines
1.1 KiB
C++
/*
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* Copyright 2016 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "SkSRGB.h"
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#include "SkTypes.h"
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#include "Test.h"
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#include <math.h>
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static uint8_t linear_to_srgb(float l) {
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return (uint8_t)roundf(sk_linear_to_srgb(Sk4f{l})[0]);
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}
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DEF_TEST(sk_linear_to_srgb, r) {
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// Should map 0 -> 0 and 1 -> 1.
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REPORTER_ASSERT(r, 0 == linear_to_srgb(0.0f));
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REPORTER_ASSERT(r, 255 == linear_to_srgb(1.0f));
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// Should be monotonic between 0 and 1.
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// We don't bother checking denorm values.
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int tolerated_regressions = 0;
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#if defined(SK_ARM_HAS_NEON)
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// Values around 0.166016 are usually 72 but drop briefly (41 floats) down to 71.
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tolerated_regressions = 1;
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#endif
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uint8_t prev = 0;
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for (float f = FLT_MIN; f <= 1.0f; ) {
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uint8_t srgb = linear_to_srgb(f);
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REPORTER_ASSERT(r, srgb >= prev || tolerated_regressions > 0);
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if (srgb < prev) { tolerated_regressions--; }
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prev = srgb;
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union { float flt; uint32_t bits; } pun = { f };
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pun.bits++;
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f = pun.flt;
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}
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}
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