Romain Guy | caaaa66 | 2017-03-27 00:40:21 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2017 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #include "Color.h" |
| 18 | |
Derek Sollenberger | be3876c | 2018-04-20 16:13:31 -0400 | [diff] [blame] | 19 | #include <utils/Log.h> |
John Reck | 339cf9b | 2018-07-18 16:32:27 -0700 | [diff] [blame] | 20 | #include <ui/ColorSpace.h> |
| 21 | |
| 22 | #include <algorithm> |
Romain Guy | caaaa66 | 2017-03-27 00:40:21 -0700 | [diff] [blame] | 23 | #include <cmath> |
| 24 | |
| 25 | namespace android { |
| 26 | namespace uirenderer { |
| 27 | |
| 28 | static inline bool almostEqual(float a, float b) { |
| 29 | return std::abs(a - b) < 1e-2f; |
| 30 | } |
| 31 | |
| 32 | bool transferFunctionCloseToSRGB(const SkColorSpace* colorSpace) { |
| 33 | if (colorSpace == nullptr) return true; |
| 34 | if (colorSpace->isSRGB()) return true; |
| 35 | |
| 36 | SkColorSpaceTransferFn transferFunction; |
| 37 | if (colorSpace->isNumericalTransferFn(&transferFunction)) { |
| 38 | // sRGB transfer function params: |
| 39 | const float sRGBParamA = 1 / 1.055f; |
| 40 | const float sRGBParamB = 0.055f / 1.055f; |
| 41 | const float sRGBParamC = 1 / 12.92f; |
| 42 | const float sRGBParamD = 0.04045f; |
| 43 | const float sRGBParamE = 0.0f; |
| 44 | const float sRGBParamF = 0.0f; |
| 45 | const float sRGBParamG = 2.4f; |
| 46 | |
| 47 | // This comparison will catch Display P3 |
John Reck | 1bcacfd | 2017-11-03 10:12:19 -0700 | [diff] [blame] | 48 | return almostEqual(sRGBParamA, transferFunction.fA) && |
| 49 | almostEqual(sRGBParamB, transferFunction.fB) && |
| 50 | almostEqual(sRGBParamC, transferFunction.fC) && |
| 51 | almostEqual(sRGBParamD, transferFunction.fD) && |
| 52 | almostEqual(sRGBParamE, transferFunction.fE) && |
| 53 | almostEqual(sRGBParamF, transferFunction.fF) && |
| 54 | almostEqual(sRGBParamG, transferFunction.fG); |
Romain Guy | caaaa66 | 2017-03-27 00:40:21 -0700 | [diff] [blame] | 55 | } |
| 56 | |
| 57 | return false; |
| 58 | } |
| 59 | |
Derek Sollenberger | be3876c | 2018-04-20 16:13:31 -0400 | [diff] [blame] | 60 | sk_sp<SkColorSpace> DataSpaceToColorSpace(android_dataspace dataspace) { |
| 61 | |
| 62 | SkColorSpace::Gamut gamut; |
| 63 | switch (dataspace & HAL_DATASPACE_STANDARD_MASK) { |
| 64 | case HAL_DATASPACE_STANDARD_BT709: |
| 65 | gamut = SkColorSpace::kSRGB_Gamut; |
| 66 | break; |
| 67 | case HAL_DATASPACE_STANDARD_BT2020: |
| 68 | gamut = SkColorSpace::kRec2020_Gamut; |
| 69 | break; |
| 70 | case HAL_DATASPACE_STANDARD_DCI_P3: |
| 71 | gamut = SkColorSpace::kDCIP3_D65_Gamut; |
| 72 | break; |
| 73 | case HAL_DATASPACE_STANDARD_ADOBE_RGB: |
| 74 | gamut = SkColorSpace::kAdobeRGB_Gamut; |
| 75 | break; |
| 76 | case HAL_DATASPACE_STANDARD_UNSPECIFIED: |
| 77 | return nullptr; |
| 78 | case HAL_DATASPACE_STANDARD_BT601_625: |
| 79 | case HAL_DATASPACE_STANDARD_BT601_625_UNADJUSTED: |
| 80 | case HAL_DATASPACE_STANDARD_BT601_525: |
| 81 | case HAL_DATASPACE_STANDARD_BT601_525_UNADJUSTED: |
| 82 | case HAL_DATASPACE_STANDARD_BT2020_CONSTANT_LUMINANCE: |
| 83 | case HAL_DATASPACE_STANDARD_BT470M: |
| 84 | case HAL_DATASPACE_STANDARD_FILM: |
| 85 | default: |
| 86 | ALOGW("Unsupported Gamut: %d", dataspace); |
| 87 | return nullptr; |
| 88 | } |
| 89 | |
| 90 | switch (dataspace & HAL_DATASPACE_TRANSFER_MASK) { |
| 91 | case HAL_DATASPACE_TRANSFER_LINEAR: |
| 92 | return SkColorSpace::MakeRGB(SkColorSpace::kLinear_RenderTargetGamma, gamut); |
| 93 | case HAL_DATASPACE_TRANSFER_SRGB: |
| 94 | return SkColorSpace::MakeRGB(SkColorSpace::kSRGB_RenderTargetGamma, gamut); |
| 95 | case HAL_DATASPACE_TRANSFER_GAMMA2_2: |
| 96 | return SkColorSpace::MakeRGB({2.2f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f}, gamut); |
| 97 | case HAL_DATASPACE_TRANSFER_GAMMA2_6: |
| 98 | return SkColorSpace::MakeRGB({2.6f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f}, gamut); |
| 99 | case HAL_DATASPACE_TRANSFER_GAMMA2_8: |
| 100 | return SkColorSpace::MakeRGB({2.8f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f}, gamut); |
| 101 | case HAL_DATASPACE_TRANSFER_UNSPECIFIED: |
| 102 | return nullptr; |
| 103 | case HAL_DATASPACE_TRANSFER_SMPTE_170M: |
| 104 | case HAL_DATASPACE_TRANSFER_ST2084: |
| 105 | case HAL_DATASPACE_TRANSFER_HLG: |
| 106 | default: |
| 107 | ALOGW("Unsupported Gamma: %d", dataspace); |
| 108 | return nullptr; |
| 109 | } |
| 110 | } |
| 111 | |
John Reck | 339cf9b | 2018-07-18 16:32:27 -0700 | [diff] [blame] | 112 | template<typename T> |
| 113 | static constexpr T clamp(T x, T min, T max) { |
| 114 | return x < min ? min : x > max ? max : x; |
| 115 | } |
| 116 | |
| 117 | //static const float2 ILLUMINANT_D50_XY = {0.34567f, 0.35850f}; |
| 118 | static const float3 ILLUMINANT_D50_XYZ = {0.964212f, 1.0f, 0.825188f}; |
| 119 | static const mat3 BRADFORD = mat3{ |
| 120 | float3{ 0.8951f, -0.7502f, 0.0389f}, |
| 121 | float3{ 0.2664f, 1.7135f, -0.0685f}, |
| 122 | float3{-0.1614f, 0.0367f, 1.0296f} |
| 123 | }; |
| 124 | |
| 125 | static mat3 adaptation(const mat3& matrix, const float3& srcWhitePoint, const float3& dstWhitePoint) { |
| 126 | float3 srcLMS = matrix * srcWhitePoint; |
| 127 | float3 dstLMS = matrix * dstWhitePoint; |
| 128 | return inverse(matrix) * mat3{dstLMS / srcLMS} * matrix; |
| 129 | } |
| 130 | |
| 131 | namespace LabColorSpace { |
| 132 | |
| 133 | static constexpr float A = 216.0f / 24389.0f; |
| 134 | static constexpr float B = 841.0f / 108.0f; |
| 135 | static constexpr float C = 4.0f / 29.0f; |
| 136 | static constexpr float D = 6.0f / 29.0f; |
| 137 | |
| 138 | float3 toXyz(const Lab& lab) { |
| 139 | float3 v { lab.L, lab.a, lab.b }; |
| 140 | v[0] = clamp(v[0], 0.0f, 100.0f); |
| 141 | v[1] = clamp(v[1], -128.0f, 128.0f); |
| 142 | v[2] = clamp(v[2], -128.0f, 128.0f); |
| 143 | |
| 144 | float fy = (v[0] + 16.0f) / 116.0f; |
| 145 | float fx = fy + (v[1] * 0.002f); |
| 146 | float fz = fy - (v[2] * 0.005f); |
| 147 | float X = fx > D ? fx * fx * fx : (1.0f / B) * (fx - C); |
| 148 | float Y = fy > D ? fy * fy * fy : (1.0f / B) * (fy - C); |
| 149 | float Z = fz > D ? fz * fz * fz : (1.0f / B) * (fz - C); |
| 150 | |
| 151 | v[0] = X * ILLUMINANT_D50_XYZ[0]; |
| 152 | v[1] = Y * ILLUMINANT_D50_XYZ[1]; |
| 153 | v[2] = Z * ILLUMINANT_D50_XYZ[2]; |
| 154 | |
| 155 | return v; |
| 156 | } |
| 157 | |
| 158 | Lab fromXyz(const float3& v) { |
| 159 | float X = v[0] / ILLUMINANT_D50_XYZ[0]; |
| 160 | float Y = v[1] / ILLUMINANT_D50_XYZ[1]; |
| 161 | float Z = v[2] / ILLUMINANT_D50_XYZ[2]; |
| 162 | |
| 163 | float fx = X > A ? pow(X, 1.0f / 3.0f) : B * X + C; |
| 164 | float fy = Y > A ? pow(Y, 1.0f / 3.0f) : B * Y + C; |
| 165 | float fz = Z > A ? pow(Z, 1.0f / 3.0f) : B * Z + C; |
| 166 | |
| 167 | float L = 116.0f * fy - 16.0f; |
| 168 | float a = 500.0f * (fx - fy); |
| 169 | float b = 200.0f * (fy - fz); |
| 170 | |
| 171 | return Lab { |
| 172 | clamp(L, 0.0f, 100.0f), |
| 173 | clamp(a, -128.0f, 128.0f), |
| 174 | clamp(b, -128.0f, 128.0f) |
| 175 | }; |
| 176 | } |
| 177 | |
| 178 | }; |
| 179 | |
| 180 | Lab sRGBToLab(SkColor color) { |
| 181 | auto colorSpace = ColorSpace::sRGB(); |
| 182 | float3 rgb; |
| 183 | rgb.r = SkColorGetR(color) / 255.0f; |
| 184 | rgb.g = SkColorGetG(color) / 255.0f; |
| 185 | rgb.b = SkColorGetB(color) / 255.0f; |
| 186 | float3 xyz = colorSpace.rgbToXYZ(rgb); |
| 187 | float3 srcXYZ = ColorSpace::XYZ(float3{colorSpace.getWhitePoint(), 1}); |
| 188 | xyz = adaptation(BRADFORD, srcXYZ, ILLUMINANT_D50_XYZ) * xyz; |
| 189 | return LabColorSpace::fromXyz(xyz); |
| 190 | } |
| 191 | |
| 192 | SkColor LabToSRGB(const Lab& lab, SkAlpha alpha) { |
| 193 | auto colorSpace = ColorSpace::sRGB(); |
| 194 | float3 xyz = LabColorSpace::toXyz(lab); |
| 195 | float3 dstXYZ = ColorSpace::XYZ(float3{colorSpace.getWhitePoint(), 1}); |
| 196 | xyz = adaptation(BRADFORD, ILLUMINANT_D50_XYZ, dstXYZ) * xyz; |
| 197 | float3 rgb = colorSpace.xyzToRGB(xyz); |
| 198 | return SkColorSetARGB(alpha, |
| 199 | static_cast<uint8_t>(rgb.r * 255), |
| 200 | static_cast<uint8_t>(rgb.g * 255), |
| 201 | static_cast<uint8_t>(rgb.b * 255)); |
| 202 | } |
| 203 | |
John Reck | 1bcacfd | 2017-11-03 10:12:19 -0700 | [diff] [blame] | 204 | }; // namespace uirenderer |
| 205 | }; // namespace android |