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 <ui/ColorSpace.h>
20 #include <utils/Log.h>
21
22 #ifdef __ANDROID__ // Layoutlib does not support hardware buffers or native windows
23 #include <android/hardware_buffer.h>
24 #include <android/native_window.h>
25 #endif
26
27 #include <algorithm>
28 #include <cmath>
29 #include <Properties.h>
30
31 namespace android {
32 namespace uirenderer {
33
34 #ifdef __ANDROID__ // Layoutlib does not support hardware buffers or native windows
createImageInfo(int32_t width,int32_t height,int32_t format,sk_sp<SkColorSpace> colorSpace)35 static inline SkImageInfo createImageInfo(int32_t width, int32_t height, int32_t format,
36 sk_sp<SkColorSpace> colorSpace) {
37 SkColorType colorType = kUnknown_SkColorType;
38 SkAlphaType alphaType = kOpaque_SkAlphaType;
39 switch (format) {
40 case AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM:
41 colorType = kN32_SkColorType;
42 alphaType = kPremul_SkAlphaType;
43 break;
44 case AHARDWAREBUFFER_FORMAT_R8G8B8X8_UNORM:
45 colorType = kN32_SkColorType;
46 alphaType = kOpaque_SkAlphaType;
47 break;
48 case AHARDWAREBUFFER_FORMAT_R5G6B5_UNORM:
49 colorType = kRGB_565_SkColorType;
50 alphaType = kOpaque_SkAlphaType;
51 break;
52 case AHARDWAREBUFFER_FORMAT_R10G10B10A2_UNORM:
53 colorType = kRGBA_1010102_SkColorType;
54 alphaType = kPremul_SkAlphaType;
55 break;
56 case AHARDWAREBUFFER_FORMAT_R16G16B16A16_FLOAT:
57 colorType = kRGBA_F16_SkColorType;
58 alphaType = kPremul_SkAlphaType;
59 break;
60 case AHARDWAREBUFFER_FORMAT_R8_UNORM:
61 colorType = kAlpha_8_SkColorType;
62 alphaType = kPremul_SkAlphaType;
63 break;
64 default:
65 ALOGV("Unsupported format: %d, return unknown by default", format);
66 break;
67 }
68 return SkImageInfo::Make(width, height, colorType, alphaType, colorSpace);
69 }
70
ANativeWindowToImageInfo(const ANativeWindow_Buffer & buffer,sk_sp<SkColorSpace> colorSpace)71 SkImageInfo ANativeWindowToImageInfo(const ANativeWindow_Buffer& buffer,
72 sk_sp<SkColorSpace> colorSpace) {
73 return createImageInfo(buffer.width, buffer.height, buffer.format, colorSpace);
74 }
75
BufferDescriptionToImageInfo(const AHardwareBuffer_Desc & bufferDesc,sk_sp<SkColorSpace> colorSpace)76 SkImageInfo BufferDescriptionToImageInfo(const AHardwareBuffer_Desc& bufferDesc,
77 sk_sp<SkColorSpace> colorSpace) {
78 return createImageInfo(bufferDesc.width, bufferDesc.height, bufferDesc.format, colorSpace);
79 }
80
ColorTypeToBufferFormat(SkColorType colorType)81 uint32_t ColorTypeToBufferFormat(SkColorType colorType) {
82 switch (colorType) {
83 case kRGBA_8888_SkColorType:
84 return AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM;
85 case kRGBA_F16_SkColorType:
86 return AHARDWAREBUFFER_FORMAT_R16G16B16A16_FLOAT;
87 case kRGB_565_SkColorType:
88 return AHARDWAREBUFFER_FORMAT_R5G6B5_UNORM;
89 case kRGB_888x_SkColorType:
90 return AHARDWAREBUFFER_FORMAT_R8G8B8X8_UNORM;
91 case kRGBA_1010102_SkColorType:
92 return AHARDWAREBUFFER_FORMAT_R10G10B10A2_UNORM;
93 case kARGB_4444_SkColorType:
94 // Hardcoding the value from android::PixelFormat
95 static constexpr uint64_t kRGBA4444 = 7;
96 return kRGBA4444;
97 case kAlpha_8_SkColorType:
98 return AHARDWAREBUFFER_FORMAT_R8_UNORM;
99 default:
100 ALOGV("Unsupported colorType: %d, return RGBA_8888 by default", (int)colorType);
101 return AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM;
102 }
103 }
104
BufferFormatToColorType(uint32_t format)105 SkColorType BufferFormatToColorType(uint32_t format) {
106 switch (format) {
107 case AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM:
108 return kN32_SkColorType;
109 case AHARDWAREBUFFER_FORMAT_R8G8B8X8_UNORM:
110 return kN32_SkColorType;
111 case AHARDWAREBUFFER_FORMAT_R5G6B5_UNORM:
112 return kRGB_565_SkColorType;
113 case AHARDWAREBUFFER_FORMAT_R10G10B10A2_UNORM:
114 return kRGBA_1010102_SkColorType;
115 case AHARDWAREBUFFER_FORMAT_R16G16B16A16_FLOAT:
116 return kRGBA_F16_SkColorType;
117 case AHARDWAREBUFFER_FORMAT_R8_UNORM:
118 return kAlpha_8_SkColorType;
119 default:
120 ALOGV("Unsupported format: %d, return unknown by default", format);
121 return kUnknown_SkColorType;
122 }
123 }
124 #endif
125
126 namespace {
127 static constexpr skcms_TransferFunction k2Dot6 = {2.6f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f};
128
129 // Skia's SkNamedGamut::kDisplayP3 is based on a white point of D65. This gamut
130 // matches the white point used by ColorSpace.Named.DCIP3.
131 static constexpr skcms_Matrix3x3 kDCIP3 = {{
132 {0.486143, 0.323835, 0.154234},
133 {0.226676, 0.710327, 0.0629966},
134 {0.000800549, 0.0432385, 0.78275},
135 }};
136
nearlyEqual(float a,float b)137 static bool nearlyEqual(float a, float b) {
138 // By trial and error, this is close enough to match for the ADataSpaces we
139 // compare for.
140 return ::fabs(a - b) < .002f;
141 }
142
nearlyEqual(const skcms_TransferFunction & x,const skcms_TransferFunction & y)143 static bool nearlyEqual(const skcms_TransferFunction& x, const skcms_TransferFunction& y) {
144 return nearlyEqual(x.g, y.g)
145 && nearlyEqual(x.a, y.a)
146 && nearlyEqual(x.b, y.b)
147 && nearlyEqual(x.c, y.c)
148 && nearlyEqual(x.d, y.d)
149 && nearlyEqual(x.e, y.e)
150 && nearlyEqual(x.f, y.f);
151 }
152
nearlyEqual(const skcms_Matrix3x3 & x,const skcms_Matrix3x3 & y)153 static bool nearlyEqual(const skcms_Matrix3x3& x, const skcms_Matrix3x3& y) {
154 for (int i = 0; i < 3; i++) {
155 for (int j = 0; j < 3; j++) {
156 if (!nearlyEqual(x.vals[i][j], y.vals[i][j])) return false;
157 }
158 }
159 return true;
160 }
161
162 } // anonymous namespace
163
ColorSpaceToADataSpace(SkColorSpace * colorSpace,SkColorType colorType)164 android_dataspace ColorSpaceToADataSpace(SkColorSpace* colorSpace, SkColorType colorType) {
165 if (!colorSpace) {
166 return HAL_DATASPACE_UNKNOWN;
167 }
168
169 if (colorSpace->isSRGB()) {
170 if (colorType == kRGBA_F16_SkColorType) {
171 return HAL_DATASPACE_V0_SCRGB;
172 }
173 return HAL_DATASPACE_V0_SRGB;
174 }
175
176 skcms_TransferFunction fn;
177 if (!colorSpace->isNumericalTransferFn(&fn)) {
178 auto res = skcms_TransferFunction_getType(&fn);
179 if (res == skcms_TFType_PQish) {
180 return HAL_DATASPACE_BT2020_PQ;
181 }
182 if (res == skcms_TFType_HLGish) {
183 return static_cast<android_dataspace>(HAL_DATASPACE_BT2020_HLG);
184 }
185 LOG_ALWAYS_FATAL("Only select non-numerical transfer functions are supported");
186 }
187
188 skcms_Matrix3x3 gamut;
189 LOG_ALWAYS_FATAL_IF(!colorSpace->toXYZD50(&gamut));
190
191 if (nearlyEqual(gamut, SkNamedGamut::kSRGB)) {
192 if (nearlyEqual(fn, SkNamedTransferFn::kLinear)) {
193 // Skia doesn't differentiate amongst the RANGES. In Java, we associate
194 // LINEAR_EXTENDED_SRGB with F16, and LINEAR_SRGB with other Configs.
195 // Make the same association here.
196 if (colorType == kRGBA_F16_SkColorType) {
197 return HAL_DATASPACE_V0_SCRGB_LINEAR;
198 }
199 return HAL_DATASPACE_V0_SRGB_LINEAR;
200 }
201
202 if (nearlyEqual(fn, SkNamedTransferFn::kRec2020)) {
203 return HAL_DATASPACE_V0_BT709;
204 }
205 }
206
207 if (nearlyEqual(fn, SkNamedTransferFn::kSRGB) && nearlyEqual(gamut, SkNamedGamut::kDisplayP3)) {
208 return HAL_DATASPACE_DISPLAY_P3;
209 }
210
211 if (nearlyEqual(fn, SkNamedTransferFn::k2Dot2) && nearlyEqual(gamut, SkNamedGamut::kAdobeRGB)) {
212 return HAL_DATASPACE_ADOBE_RGB;
213 }
214
215 if (nearlyEqual(fn, SkNamedTransferFn::kRec2020) &&
216 nearlyEqual(gamut, SkNamedGamut::kRec2020)) {
217 return HAL_DATASPACE_BT2020;
218 }
219
220 if (nearlyEqual(fn, k2Dot6) && nearlyEqual(gamut, kDCIP3)) {
221 return HAL_DATASPACE_DCI_P3;
222 }
223
224 return HAL_DATASPACE_UNKNOWN;
225 }
226
DataSpaceToColorSpace(android_dataspace dataspace)227 sk_sp<SkColorSpace> DataSpaceToColorSpace(android_dataspace dataspace) {
228 if (dataspace == HAL_DATASPACE_UNKNOWN) {
229 return SkColorSpace::MakeSRGB();
230 }
231 if (dataspace == HAL_DATASPACE_DCI_P3) {
232 // This cannot be handled by the switch statements below because it
233 // needs to use the locally-defined kDCIP3 gamut, rather than the one in
234 // Skia (SkNamedGamut), which is used for other data spaces with
235 // HAL_DATASPACE_STANDARD_DCI_P3 (e.g. HAL_DATASPACE_DISPLAY_P3).
236 return SkColorSpace::MakeRGB(k2Dot6, kDCIP3);
237 }
238
239 skcms_Matrix3x3 gamut;
240 switch (dataspace & HAL_DATASPACE_STANDARD_MASK) {
241 case HAL_DATASPACE_STANDARD_BT709:
242 gamut = SkNamedGamut::kSRGB;
243 break;
244 case HAL_DATASPACE_STANDARD_BT2020:
245 case HAL_DATASPACE_STANDARD_BT2020_CONSTANT_LUMINANCE:
246 gamut = SkNamedGamut::kRec2020;
247 break;
248 case HAL_DATASPACE_STANDARD_DCI_P3:
249 gamut = SkNamedGamut::kDisplayP3;
250 break;
251 case HAL_DATASPACE_STANDARD_ADOBE_RGB:
252 gamut = SkNamedGamut::kAdobeRGB;
253 break;
254 case HAL_DATASPACE_STANDARD_UNSPECIFIED:
255 return nullptr;
256 case HAL_DATASPACE_STANDARD_BT601_625:
257 case HAL_DATASPACE_STANDARD_BT601_625_UNADJUSTED:
258 case HAL_DATASPACE_STANDARD_BT601_525:
259 case HAL_DATASPACE_STANDARD_BT601_525_UNADJUSTED:
260 case HAL_DATASPACE_STANDARD_BT470M:
261 case HAL_DATASPACE_STANDARD_FILM:
262 default:
263 ALOGV("Unsupported Gamut: %d", dataspace);
264 return nullptr;
265 }
266
267 // HLG
268 if ((dataspace & HAL_DATASPACE_TRANSFER_MASK) == HAL_DATASPACE_TRANSFER_HLG) {
269 const auto hlgFn = GetHLGScaleTransferFunction();
270 if (hlgFn.has_value()) {
271 return SkColorSpace::MakeRGB(hlgFn.value(), gamut);
272 }
273 }
274
275 switch (dataspace & HAL_DATASPACE_TRANSFER_MASK) {
276 case HAL_DATASPACE_TRANSFER_LINEAR:
277 return SkColorSpace::MakeRGB(SkNamedTransferFn::kLinear, gamut);
278 case HAL_DATASPACE_TRANSFER_SRGB:
279 return SkColorSpace::MakeRGB(SkNamedTransferFn::kSRGB, gamut);
280 case HAL_DATASPACE_TRANSFER_GAMMA2_2:
281 return SkColorSpace::MakeRGB({2.2f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f}, gamut);
282 case HAL_DATASPACE_TRANSFER_GAMMA2_6:
283 return SkColorSpace::MakeRGB(k2Dot6, gamut);
284 case HAL_DATASPACE_TRANSFER_GAMMA2_8:
285 return SkColorSpace::MakeRGB({2.8f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f}, gamut);
286 case HAL_DATASPACE_TRANSFER_ST2084:
287 return SkColorSpace::MakeRGB({-2.0, -1.555223, 1.860454, 32 / 2523.0, 2413 / 128.0,
288 -2392 / 128.0, 8192 / 1305.0},
289 gamut);
290 case HAL_DATASPACE_TRANSFER_SMPTE_170M:
291 return SkColorSpace::MakeRGB(SkNamedTransferFn::kRec2020, gamut);
292 case HAL_DATASPACE_TRANSFER_UNSPECIFIED:
293 return nullptr;
294 default:
295 ALOGV("Unsupported Gamma: %d", dataspace);
296 return nullptr;
297 }
298 }
299
300 template<typename T>
clamp(T x,T min,T max)301 static constexpr T clamp(T x, T min, T max) {
302 return x < min ? min : x > max ? max : x;
303 }
304
305 //static const float2 ILLUMINANT_D50_XY = {0.34567f, 0.35850f};
306 static const float3 ILLUMINANT_D50_XYZ = {0.964212f, 1.0f, 0.825188f};
307 static const mat3 BRADFORD = mat3{
308 float3{ 0.8951f, -0.7502f, 0.0389f},
309 float3{ 0.2664f, 1.7135f, -0.0685f},
310 float3{-0.1614f, 0.0367f, 1.0296f}
311 };
312
adaptation(const mat3 & matrix,const float3 & srcWhitePoint,const float3 & dstWhitePoint)313 static mat3 adaptation(const mat3& matrix, const float3& srcWhitePoint, const float3& dstWhitePoint) {
314 float3 srcLMS = matrix * srcWhitePoint;
315 float3 dstLMS = matrix * dstWhitePoint;
316 return inverse(matrix) * mat3{dstLMS / srcLMS} * matrix;
317 }
318
319 namespace LabColorSpace {
320
321 static constexpr float A = 216.0f / 24389.0f;
322 static constexpr float B = 841.0f / 108.0f;
323 static constexpr float C = 4.0f / 29.0f;
324 static constexpr float D = 6.0f / 29.0f;
325
toXyz(const Lab & lab)326 float3 toXyz(const Lab& lab) {
327 float3 v { lab.L, lab.a, lab.b };
328 v[0] = clamp(v[0], 0.0f, 100.0f);
329 v[1] = clamp(v[1], -128.0f, 128.0f);
330 v[2] = clamp(v[2], -128.0f, 128.0f);
331
332 float fy = (v[0] + 16.0f) / 116.0f;
333 float fx = fy + (v[1] * 0.002f);
334 float fz = fy - (v[2] * 0.005f);
335 float X = fx > D ? fx * fx * fx : (1.0f / B) * (fx - C);
336 float Y = fy > D ? fy * fy * fy : (1.0f / B) * (fy - C);
337 float Z = fz > D ? fz * fz * fz : (1.0f / B) * (fz - C);
338
339 v[0] = X * ILLUMINANT_D50_XYZ[0];
340 v[1] = Y * ILLUMINANT_D50_XYZ[1];
341 v[2] = Z * ILLUMINANT_D50_XYZ[2];
342
343 return v;
344 }
345
fromXyz(const float3 & v)346 Lab fromXyz(const float3& v) {
347 float X = v[0] / ILLUMINANT_D50_XYZ[0];
348 float Y = v[1] / ILLUMINANT_D50_XYZ[1];
349 float Z = v[2] / ILLUMINANT_D50_XYZ[2];
350
351 float fx = X > A ? pow(X, 1.0f / 3.0f) : B * X + C;
352 float fy = Y > A ? pow(Y, 1.0f / 3.0f) : B * Y + C;
353 float fz = Z > A ? pow(Z, 1.0f / 3.0f) : B * Z + C;
354
355 float L = 116.0f * fy - 16.0f;
356 float a = 500.0f * (fx - fy);
357 float b = 200.0f * (fy - fz);
358
359 return Lab {
360 clamp(L, 0.0f, 100.0f),
361 clamp(a, -128.0f, 128.0f),
362 clamp(b, -128.0f, 128.0f)
363 };
364 }
365
366 };
367
sRGBToLab(SkColor color)368 Lab sRGBToLab(SkColor color) {
369 auto colorSpace = ColorSpace::sRGB();
370 float3 rgb;
371 rgb.r = SkColorGetR(color) / 255.0f;
372 rgb.g = SkColorGetG(color) / 255.0f;
373 rgb.b = SkColorGetB(color) / 255.0f;
374 float3 xyz = colorSpace.rgbToXYZ(rgb);
375 float3 srcXYZ = ColorSpace::XYZ(float3{colorSpace.getWhitePoint(), 1});
376 xyz = adaptation(BRADFORD, srcXYZ, ILLUMINANT_D50_XYZ) * xyz;
377 return LabColorSpace::fromXyz(xyz);
378 }
379
LabToSRGB(const Lab & lab,SkAlpha alpha)380 SkColor LabToSRGB(const Lab& lab, SkAlpha alpha) {
381 auto colorSpace = ColorSpace::sRGB();
382 float3 xyz = LabColorSpace::toXyz(lab);
383 float3 dstXYZ = ColorSpace::XYZ(float3{colorSpace.getWhitePoint(), 1});
384 xyz = adaptation(BRADFORD, ILLUMINANT_D50_XYZ, dstXYZ) * xyz;
385 float3 rgb = colorSpace.xyzToRGB(xyz);
386 return SkColorSetARGB(alpha,
387 static_cast<uint8_t>(rgb.r * 255),
388 static_cast<uint8_t>(rgb.g * 255),
389 static_cast<uint8_t>(rgb.b * 255));
390 }
391
GetPQSkTransferFunction(float sdr_white_level)392 skcms_TransferFunction GetPQSkTransferFunction(float sdr_white_level) {
393 if (sdr_white_level <= 0.f) {
394 sdr_white_level = Properties::defaultSdrWhitePoint;
395 }
396 // The generic PQ transfer function produces normalized luminance values i.e.
397 // the range 0-1 represents 0-10000 nits for the reference display, but we
398 // want to map 1.0 to |sdr_white_level| nits so we need to scale accordingly.
399 const double w = 10000. / sdr_white_level;
400 // Distribute scaling factor W by scaling A and B with X ^ (1/F):
401 // ((A + Bx^C) / (D + Ex^C))^F * W = ((A + Bx^C) / (D + Ex^C) * W^(1/F))^F
402 // See https://crbug.com/1058580#c32 for discussion.
403 skcms_TransferFunction fn = SkNamedTransferFn::kPQ;
404 const double ws = pow(w, 1. / fn.f);
405 fn.a = ws * fn.a;
406 fn.b = ws * fn.b;
407 return fn;
408 }
409
trfn_apply_gain(const skcms_TransferFunction trfn,float gain)410 static skcms_TransferFunction trfn_apply_gain(const skcms_TransferFunction trfn, float gain) {
411 float pow_gain_ginv = sk_float_pow(gain, 1 / trfn.g);
412 skcms_TransferFunction result;
413 result.g = trfn.g;
414 result.a = trfn.a * pow_gain_ginv;
415 result.b = trfn.b * pow_gain_ginv;
416 result.c = trfn.c * gain;
417 result.d = trfn.d;
418 result.e = trfn.e * gain;
419 result.f = trfn.f * gain;
420 return result;
421 }
422
GetExtendedTransferFunction(float sdrHdrRatio)423 skcms_TransferFunction GetExtendedTransferFunction(float sdrHdrRatio) {
424 if (sdrHdrRatio <= 1.f) {
425 return SkNamedTransferFn::kSRGB;
426 }
427 // Scale the transfer by the sdrHdrRatio
428 return trfn_apply_gain(SkNamedTransferFn::kSRGB, sdrHdrRatio);
429 }
430
431 // Skia skcms' default HLG maps encoded [0, 1] to linear [1, 12] in order to follow ARIB
432 // but LinearEffect expects to map 1.0 == 203 nits
GetHLGScaleTransferFunction()433 std::optional<skcms_TransferFunction> GetHLGScaleTransferFunction() {
434 skcms_TransferFunction hlgFn;
435 if (skcms_TransferFunction_makeScaledHLGish(&hlgFn, 0.314509843, 2.f, 2.f, 1.f / 0.17883277f,
436 0.28466892f, 0.55991073f)) {
437 return std::make_optional<skcms_TransferFunction>(hlgFn);
438 }
439 return {};
440 }
441
442 } // namespace uirenderer
443 } // namespace android
444