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
19 #include <Properties.h>
20 #include <android/hardware_buffer.h>
21 #include <android/native_window.h>
22 #include <ui/ColorSpace.h>
23 #include <utils/Log.h>
24
25 #include <algorithm>
26 #include <cmath>
27
28 namespace android {
29 namespace uirenderer {
30
createImageInfo(int32_t width,int32_t height,int32_t format,sk_sp<SkColorSpace> colorSpace)31 static inline SkImageInfo createImageInfo(int32_t width, int32_t height, int32_t format,
32 sk_sp<SkColorSpace> colorSpace) {
33 SkColorType colorType = kUnknown_SkColorType;
34 SkAlphaType alphaType = kOpaque_SkAlphaType;
35 switch (format) {
36 case AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM:
37 colorType = kN32_SkColorType;
38 alphaType = kPremul_SkAlphaType;
39 break;
40 case AHARDWAREBUFFER_FORMAT_R8G8B8X8_UNORM:
41 colorType = kN32_SkColorType;
42 alphaType = kOpaque_SkAlphaType;
43 break;
44 case AHARDWAREBUFFER_FORMAT_R5G6B5_UNORM:
45 colorType = kRGB_565_SkColorType;
46 alphaType = kOpaque_SkAlphaType;
47 break;
48 case AHARDWAREBUFFER_FORMAT_R10G10B10A2_UNORM:
49 colorType = kRGBA_1010102_SkColorType;
50 alphaType = kPremul_SkAlphaType;
51 break;
52 case AHARDWAREBUFFER_FORMAT_R16G16B16A16_FLOAT:
53 colorType = kRGBA_F16_SkColorType;
54 alphaType = kPremul_SkAlphaType;
55 break;
56 case AHARDWAREBUFFER_FORMAT_R8_UNORM:
57 colorType = kAlpha_8_SkColorType;
58 alphaType = kPremul_SkAlphaType;
59 break;
60 default:
61 ALOGV("Unsupported format: %d, return unknown by default", format);
62 break;
63 }
64 return SkImageInfo::Make(width, height, colorType, alphaType, colorSpace);
65 }
66
ANativeWindowToImageInfo(const ANativeWindow_Buffer & buffer,sk_sp<SkColorSpace> colorSpace)67 SkImageInfo ANativeWindowToImageInfo(const ANativeWindow_Buffer& buffer,
68 sk_sp<SkColorSpace> colorSpace) {
69 return createImageInfo(buffer.width, buffer.height, buffer.format, colorSpace);
70 }
71
BufferDescriptionToImageInfo(const AHardwareBuffer_Desc & bufferDesc,sk_sp<SkColorSpace> colorSpace)72 SkImageInfo BufferDescriptionToImageInfo(const AHardwareBuffer_Desc& bufferDesc,
73 sk_sp<SkColorSpace> colorSpace) {
74 return createImageInfo(bufferDesc.width, bufferDesc.height, bufferDesc.format, colorSpace);
75 }
76
ColorTypeToBufferFormat(SkColorType colorType)77 uint32_t ColorTypeToBufferFormat(SkColorType colorType) {
78 switch (colorType) {
79 case kRGBA_8888_SkColorType:
80 return AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM;
81 case kRGBA_F16_SkColorType:
82 return AHARDWAREBUFFER_FORMAT_R16G16B16A16_FLOAT;
83 case kRGB_565_SkColorType:
84 return AHARDWAREBUFFER_FORMAT_R5G6B5_UNORM;
85 case kRGB_888x_SkColorType:
86 return AHARDWAREBUFFER_FORMAT_R8G8B8X8_UNORM;
87 case kRGBA_1010102_SkColorType:
88 return AHARDWAREBUFFER_FORMAT_R10G10B10A2_UNORM;
89 case kARGB_4444_SkColorType:
90 // Hardcoding the value from android::PixelFormat
91 static constexpr uint64_t kRGBA4444 = 7;
92 return kRGBA4444;
93 case kAlpha_8_SkColorType:
94 return AHARDWAREBUFFER_FORMAT_R8_UNORM;
95 default:
96 ALOGV("Unsupported colorType: %d, return RGBA_8888 by default", (int)colorType);
97 return AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM;
98 }
99 }
100
BufferFormatToColorType(uint32_t format)101 SkColorType BufferFormatToColorType(uint32_t format) {
102 switch (format) {
103 case AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM:
104 return kN32_SkColorType;
105 case AHARDWAREBUFFER_FORMAT_R8G8B8X8_UNORM:
106 return kN32_SkColorType;
107 case AHARDWAREBUFFER_FORMAT_R5G6B5_UNORM:
108 return kRGB_565_SkColorType;
109 case AHARDWAREBUFFER_FORMAT_R10G10B10A2_UNORM:
110 return kRGBA_1010102_SkColorType;
111 case AHARDWAREBUFFER_FORMAT_R16G16B16A16_FLOAT:
112 return kRGBA_F16_SkColorType;
113 case AHARDWAREBUFFER_FORMAT_R8_UNORM:
114 return kAlpha_8_SkColorType;
115 default:
116 ALOGV("Unsupported format: %d, return unknown by default", format);
117 return kUnknown_SkColorType;
118 }
119 }
120
121 namespace {
122 static constexpr skcms_TransferFunction k2Dot6 = {2.6f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f};
123
124 // Skia's SkNamedGamut::kDisplayP3 is based on a white point of D65. This gamut
125 // matches the white point used by ColorSpace.Named.DCIP3.
126 static constexpr skcms_Matrix3x3 kDCIP3 = {{
127 {0.486143, 0.323835, 0.154234},
128 {0.226676, 0.710327, 0.0629966},
129 {0.000800549, 0.0432385, 0.78275},
130 }};
131
nearlyEqual(float a,float b)132 static bool nearlyEqual(float a, float b) {
133 // By trial and error, this is close enough to match for the ADataSpaces we
134 // compare for.
135 return ::fabs(a - b) < .002f;
136 }
137
nearlyEqual(const skcms_TransferFunction & x,const skcms_TransferFunction & y)138 static bool nearlyEqual(const skcms_TransferFunction& x, const skcms_TransferFunction& y) {
139 return nearlyEqual(x.g, y.g)
140 && nearlyEqual(x.a, y.a)
141 && nearlyEqual(x.b, y.b)
142 && nearlyEqual(x.c, y.c)
143 && nearlyEqual(x.d, y.d)
144 && nearlyEqual(x.e, y.e)
145 && nearlyEqual(x.f, y.f);
146 }
147
nearlyEqual(const skcms_Matrix3x3 & x,const skcms_Matrix3x3 & y)148 static bool nearlyEqual(const skcms_Matrix3x3& x, const skcms_Matrix3x3& y) {
149 for (int i = 0; i < 3; i++) {
150 for (int j = 0; j < 3; j++) {
151 if (!nearlyEqual(x.vals[i][j], y.vals[i][j])) return false;
152 }
153 }
154 return true;
155 }
156
157 } // anonymous namespace
158
ColorSpaceToADataSpace(SkColorSpace * colorSpace,SkColorType colorType)159 android_dataspace ColorSpaceToADataSpace(SkColorSpace* colorSpace, SkColorType colorType) {
160 if (!colorSpace) {
161 return HAL_DATASPACE_UNKNOWN;
162 }
163
164 if (colorSpace->isSRGB()) {
165 if (colorType == kRGBA_F16_SkColorType) {
166 return HAL_DATASPACE_V0_SCRGB;
167 }
168 return HAL_DATASPACE_V0_SRGB;
169 }
170
171 skcms_TransferFunction fn;
172 if (!colorSpace->isNumericalTransferFn(&fn)) {
173 auto res = skcms_TransferFunction_getType(&fn);
174 if (res == skcms_TFType_PQish) {
175 return HAL_DATASPACE_BT2020_PQ;
176 }
177 if (res == skcms_TFType_HLGish) {
178 return static_cast<android_dataspace>(HAL_DATASPACE_BT2020_HLG);
179 }
180 LOG_ALWAYS_FATAL("Only select non-numerical transfer functions are supported");
181 }
182
183 skcms_Matrix3x3 gamut;
184 LOG_ALWAYS_FATAL_IF(!colorSpace->toXYZD50(&gamut));
185
186 if (nearlyEqual(gamut, SkNamedGamut::kSRGB)) {
187 if (nearlyEqual(fn, SkNamedTransferFn::kLinear)) {
188 // Skia doesn't differentiate amongst the RANGES. In Java, we associate
189 // LINEAR_EXTENDED_SRGB with F16, and LINEAR_SRGB with other Configs.
190 // Make the same association here.
191 if (colorType == kRGBA_F16_SkColorType) {
192 return HAL_DATASPACE_V0_SCRGB_LINEAR;
193 }
194 return HAL_DATASPACE_V0_SRGB_LINEAR;
195 }
196
197 if (nearlyEqual(fn, SkNamedTransferFn::kRec2020)) {
198 return HAL_DATASPACE_V0_BT709;
199 }
200 }
201
202 if (nearlyEqual(fn, SkNamedTransferFn::kSRGB) && nearlyEqual(gamut, SkNamedGamut::kDisplayP3)) {
203 return HAL_DATASPACE_DISPLAY_P3;
204 }
205
206 if (nearlyEqual(fn, SkNamedTransferFn::k2Dot2) && nearlyEqual(gamut, SkNamedGamut::kAdobeRGB)) {
207 return HAL_DATASPACE_ADOBE_RGB;
208 }
209
210 if (nearlyEqual(fn, SkNamedTransferFn::kRec2020) &&
211 nearlyEqual(gamut, SkNamedGamut::kRec2020)) {
212 return HAL_DATASPACE_BT2020;
213 }
214
215 if (nearlyEqual(fn, k2Dot6) && nearlyEqual(gamut, kDCIP3)) {
216 return HAL_DATASPACE_DCI_P3;
217 }
218
219 return HAL_DATASPACE_UNKNOWN;
220 }
221
DataSpaceToColorSpace(android_dataspace dataspace)222 sk_sp<SkColorSpace> DataSpaceToColorSpace(android_dataspace dataspace) {
223 if (dataspace == HAL_DATASPACE_UNKNOWN) {
224 return SkColorSpace::MakeSRGB();
225 }
226 if (dataspace == HAL_DATASPACE_DCI_P3) {
227 // This cannot be handled by the switch statements below because it
228 // needs to use the locally-defined kDCIP3 gamut, rather than the one in
229 // Skia (SkNamedGamut), which is used for other data spaces with
230 // HAL_DATASPACE_STANDARD_DCI_P3 (e.g. HAL_DATASPACE_DISPLAY_P3).
231 return SkColorSpace::MakeRGB(k2Dot6, kDCIP3);
232 }
233
234 skcms_Matrix3x3 gamut;
235 switch (dataspace & HAL_DATASPACE_STANDARD_MASK) {
236 case HAL_DATASPACE_STANDARD_BT709:
237 gamut = SkNamedGamut::kSRGB;
238 break;
239 case HAL_DATASPACE_STANDARD_BT2020:
240 case HAL_DATASPACE_STANDARD_BT2020_CONSTANT_LUMINANCE:
241 gamut = SkNamedGamut::kRec2020;
242 break;
243 case HAL_DATASPACE_STANDARD_DCI_P3:
244 gamut = SkNamedGamut::kDisplayP3;
245 break;
246 case HAL_DATASPACE_STANDARD_ADOBE_RGB:
247 gamut = SkNamedGamut::kAdobeRGB;
248 break;
249 case HAL_DATASPACE_STANDARD_UNSPECIFIED:
250 return nullptr;
251 case HAL_DATASPACE_STANDARD_BT601_625:
252 case HAL_DATASPACE_STANDARD_BT601_625_UNADJUSTED:
253 case HAL_DATASPACE_STANDARD_BT601_525:
254 case HAL_DATASPACE_STANDARD_BT601_525_UNADJUSTED:
255 case HAL_DATASPACE_STANDARD_BT470M:
256 case HAL_DATASPACE_STANDARD_FILM:
257 default:
258 ALOGV("Unsupported Gamut: %d", dataspace);
259 return nullptr;
260 }
261
262 // HLG
263 if ((dataspace & HAL_DATASPACE_TRANSFER_MASK) == HAL_DATASPACE_TRANSFER_HLG) {
264 const auto hlgFn = GetHLGScaleTransferFunction();
265 if (hlgFn.has_value()) {
266 return SkColorSpace::MakeRGB(hlgFn.value(), gamut);
267 }
268 }
269
270 switch (dataspace & HAL_DATASPACE_TRANSFER_MASK) {
271 case HAL_DATASPACE_TRANSFER_LINEAR:
272 return SkColorSpace::MakeRGB(SkNamedTransferFn::kLinear, gamut);
273 case HAL_DATASPACE_TRANSFER_SRGB:
274 return SkColorSpace::MakeRGB(SkNamedTransferFn::kSRGB, gamut);
275 case HAL_DATASPACE_TRANSFER_GAMMA2_2:
276 return SkColorSpace::MakeRGB({2.2f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f}, gamut);
277 case HAL_DATASPACE_TRANSFER_GAMMA2_6:
278 return SkColorSpace::MakeRGB(k2Dot6, gamut);
279 case HAL_DATASPACE_TRANSFER_GAMMA2_8:
280 return SkColorSpace::MakeRGB({2.8f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f}, gamut);
281 case HAL_DATASPACE_TRANSFER_ST2084:
282 return SkColorSpace::MakeRGB({-2.0, -1.555223, 1.860454, 32 / 2523.0, 2413 / 128.0,
283 -2392 / 128.0, 8192 / 1305.0},
284 gamut);
285 case HAL_DATASPACE_TRANSFER_SMPTE_170M:
286 return SkColorSpace::MakeRGB(SkNamedTransferFn::kRec2020, gamut);
287 case HAL_DATASPACE_TRANSFER_UNSPECIFIED:
288 return nullptr;
289 default:
290 ALOGV("Unsupported Gamma: %d", dataspace);
291 return nullptr;
292 }
293 }
294
295 template<typename T>
clamp(T x,T min,T max)296 static constexpr T clamp(T x, T min, T max) {
297 return x < min ? min : x > max ? max : x;
298 }
299
300 //static const float2 ILLUMINANT_D50_XY = {0.34567f, 0.35850f};
301 static const float3 ILLUMINANT_D50_XYZ = {0.964212f, 1.0f, 0.825188f};
302 static const mat3 BRADFORD = mat3{
303 float3{ 0.8951f, -0.7502f, 0.0389f},
304 float3{ 0.2664f, 1.7135f, -0.0685f},
305 float3{-0.1614f, 0.0367f, 1.0296f}
306 };
307
adaptation(const mat3 & matrix,const float3 & srcWhitePoint,const float3 & dstWhitePoint)308 static mat3 adaptation(const mat3& matrix, const float3& srcWhitePoint, const float3& dstWhitePoint) {
309 float3 srcLMS = matrix * srcWhitePoint;
310 float3 dstLMS = matrix * dstWhitePoint;
311 return inverse(matrix) * mat3{dstLMS / srcLMS} * matrix;
312 }
313
314 namespace LabColorSpace {
315
316 static constexpr float A = 216.0f / 24389.0f;
317 static constexpr float B = 841.0f / 108.0f;
318 static constexpr float C = 4.0f / 29.0f;
319 static constexpr float D = 6.0f / 29.0f;
320
toXyz(const Lab & lab)321 float3 toXyz(const Lab& lab) {
322 float3 v { lab.L, lab.a, lab.b };
323 v[0] = clamp(v[0], 0.0f, 100.0f);
324 v[1] = clamp(v[1], -128.0f, 128.0f);
325 v[2] = clamp(v[2], -128.0f, 128.0f);
326
327 float fy = (v[0] + 16.0f) / 116.0f;
328 float fx = fy + (v[1] * 0.002f);
329 float fz = fy - (v[2] * 0.005f);
330 float X = fx > D ? fx * fx * fx : (1.0f / B) * (fx - C);
331 float Y = fy > D ? fy * fy * fy : (1.0f / B) * (fy - C);
332 float Z = fz > D ? fz * fz * fz : (1.0f / B) * (fz - C);
333
334 v[0] = X * ILLUMINANT_D50_XYZ[0];
335 v[1] = Y * ILLUMINANT_D50_XYZ[1];
336 v[2] = Z * ILLUMINANT_D50_XYZ[2];
337
338 return v;
339 }
340
fromXyz(const float3 & v)341 Lab fromXyz(const float3& v) {
342 float X = v[0] / ILLUMINANT_D50_XYZ[0];
343 float Y = v[1] / ILLUMINANT_D50_XYZ[1];
344 float Z = v[2] / ILLUMINANT_D50_XYZ[2];
345
346 float fx = X > A ? pow(X, 1.0f / 3.0f) : B * X + C;
347 float fy = Y > A ? pow(Y, 1.0f / 3.0f) : B * Y + C;
348 float fz = Z > A ? pow(Z, 1.0f / 3.0f) : B * Z + C;
349
350 float L = 116.0f * fy - 16.0f;
351 float a = 500.0f * (fx - fy);
352 float b = 200.0f * (fy - fz);
353
354 return Lab {
355 clamp(L, 0.0f, 100.0f),
356 clamp(a, -128.0f, 128.0f),
357 clamp(b, -128.0f, 128.0f)
358 };
359 }
360
361 };
362
sRGBToLab(SkColor color)363 Lab sRGBToLab(SkColor color) {
364 auto colorSpace = ColorSpace::sRGB();
365 float3 rgb;
366 rgb.r = SkColorGetR(color) / 255.0f;
367 rgb.g = SkColorGetG(color) / 255.0f;
368 rgb.b = SkColorGetB(color) / 255.0f;
369 float3 xyz = colorSpace.rgbToXYZ(rgb);
370 float3 srcXYZ = ColorSpace::XYZ(float3{colorSpace.getWhitePoint(), 1});
371 xyz = adaptation(BRADFORD, srcXYZ, ILLUMINANT_D50_XYZ) * xyz;
372 return LabColorSpace::fromXyz(xyz);
373 }
374
LabToSRGB(const Lab & lab,SkAlpha alpha)375 SkColor LabToSRGB(const Lab& lab, SkAlpha alpha) {
376 auto colorSpace = ColorSpace::sRGB();
377 float3 xyz = LabColorSpace::toXyz(lab);
378 float3 dstXYZ = ColorSpace::XYZ(float3{colorSpace.getWhitePoint(), 1});
379 xyz = adaptation(BRADFORD, ILLUMINANT_D50_XYZ, dstXYZ) * xyz;
380 float3 rgb = colorSpace.xyzToRGB(xyz);
381 return SkColorSetARGB(alpha,
382 static_cast<uint8_t>(rgb.r * 255),
383 static_cast<uint8_t>(rgb.g * 255),
384 static_cast<uint8_t>(rgb.b * 255));
385 }
386
GetPQSkTransferFunction(float sdr_white_level)387 skcms_TransferFunction GetPQSkTransferFunction(float sdr_white_level) {
388 if (sdr_white_level <= 0.f) {
389 sdr_white_level = Properties::defaultSdrWhitePoint;
390 }
391 // The generic PQ transfer function produces normalized luminance values i.e.
392 // the range 0-1 represents 0-10000 nits for the reference display, but we
393 // want to map 1.0 to |sdr_white_level| nits so we need to scale accordingly.
394 const double w = 10000. / sdr_white_level;
395 // Distribute scaling factor W by scaling A and B with X ^ (1/F):
396 // ((A + Bx^C) / (D + Ex^C))^F * W = ((A + Bx^C) / (D + Ex^C) * W^(1/F))^F
397 // See https://crbug.com/1058580#c32 for discussion.
398 skcms_TransferFunction fn = SkNamedTransferFn::kPQ;
399 const double ws = pow(w, 1. / fn.f);
400 fn.a = ws * fn.a;
401 fn.b = ws * fn.b;
402 return fn;
403 }
404
trfn_apply_gain(const skcms_TransferFunction trfn,float gain)405 static skcms_TransferFunction trfn_apply_gain(const skcms_TransferFunction trfn, float gain) {
406 float pow_gain_ginv = std::pow(gain, 1 / trfn.g);
407 skcms_TransferFunction result;
408 result.g = trfn.g;
409 result.a = trfn.a * pow_gain_ginv;
410 result.b = trfn.b * pow_gain_ginv;
411 result.c = trfn.c * gain;
412 result.d = trfn.d;
413 result.e = trfn.e * gain;
414 result.f = trfn.f * gain;
415 return result;
416 }
417
GetExtendedTransferFunction(float sdrHdrRatio)418 skcms_TransferFunction GetExtendedTransferFunction(float sdrHdrRatio) {
419 if (sdrHdrRatio <= 1.f) {
420 return SkNamedTransferFn::kSRGB;
421 }
422 // Scale the transfer by the sdrHdrRatio
423 return trfn_apply_gain(SkNamedTransferFn::kSRGB, sdrHdrRatio);
424 }
425
426 // Skia skcms' default HLG maps encoded [0, 1] to linear [1, 12] in order to follow ARIB
427 // but LinearEffect expects to map 1.0 == 203 nits
GetHLGScaleTransferFunction()428 std::optional<skcms_TransferFunction> GetHLGScaleTransferFunction() {
429 skcms_TransferFunction hlgFn;
430 if (skcms_TransferFunction_makeScaledHLGish(&hlgFn, 0.314509843, 2.f, 2.f, 1.f / 0.17883277f,
431 0.28466892f, 0.55991073f)) {
432 return std::make_optional<skcms_TransferFunction>(hlgFn);
433 }
434 return {};
435 }
436
437 } // namespace uirenderer
438 } // namespace android
439