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/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "Color.h"
#include <cmath>
namespace android {
namespace uirenderer {
static inline bool almostEqual(float a, float b) {
return std::abs(a - b) < 1e-2f;
}
bool transferFunctionCloseToSRGB(const SkColorSpace* colorSpace) {
if (colorSpace == nullptr) return true;
if (colorSpace->isSRGB()) return true;
SkColorSpaceTransferFn transferFunction;
if (colorSpace->isNumericalTransferFn(&transferFunction)) {
// sRGB transfer function params:
const float sRGBParamA = 1 / 1.055f;
const float sRGBParamB = 0.055f / 1.055f;
const float sRGBParamC = 1 / 12.92f;
const float sRGBParamD = 0.04045f;
const float sRGBParamE = 0.0f;
const float sRGBParamF = 0.0f;
const float sRGBParamG = 2.4f;
// This comparison will catch Display P3
return
almostEqual(sRGBParamA, transferFunction.fA)
&& almostEqual(sRGBParamB, transferFunction.fB)
&& almostEqual(sRGBParamC, transferFunction.fC)
&& almostEqual(sRGBParamD, transferFunction.fD)
&& almostEqual(sRGBParamE, transferFunction.fE)
&& almostEqual(sRGBParamF, transferFunction.fF)
&& almostEqual(sRGBParamG, transferFunction.fG);
}
return false;
}
}; // namespace uirenderer
}; // namespace android
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