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- /*
- * Copyright 2019 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- #include "include/core/SkMatrix44.h"
- #include "src/core/SkYUVMath.h"
- // in SkColorMatrix order (row-major)
- // Created by running SkColorMatrix_DumpYUVMatrixTables()
- const float Rec709_rgb_to_yuv[] = {
- 0.182586f, 0.614231f, 0.062007f, 0.000000f, 0.062745f,
- -0.100644f, -0.338572f, 0.439216f, 0.000000f, 0.501961f,
- 0.439216f, -0.398942f, -0.040274f, 0.000000f, 0.501961f,
- 0.000000f, 0.000000f, 0.000000f, 1.000000f, 0.000000f,
- };
- const float Rec709_yuv_to_rgb[] = {
- 1.164384f, 0.000000f, 1.792741f, 0.000000f, -0.972945f,
- 1.164384f, -0.213249f, -0.532909f, 0.000000f, 0.301483f,
- 1.164384f, 2.112402f, 0.000000f, 0.000000f, -1.133402f,
- 0.000000f, 0.000000f, 0.000000f, 1.000000f, 0.000000f,
- };
- const float Rec601_rgb_to_yuv[] = {
- 0.256788f, 0.504129f, 0.097906f, 0.000000f, 0.062745f,
- -0.148223f, -0.290993f, 0.439216f, 0.000000f, 0.501961f,
- 0.439216f, -0.367788f, -0.071427f, 0.000000f, 0.501961f,
- 0.000000f, 0.000000f, 0.000000f, 1.000000f, 0.000000f,
- };
- const float Rec601_yuv_to_rgb[] = {
- 1.164384f, 0.000000f, 1.596027f, 0.000000f, -0.874202f,
- 1.164384f, -0.391762f, -0.812968f, 0.000000f, 0.531668f,
- 1.164384f, 2.017232f, 0.000000f, 0.000000f, -1.085631f,
- 0.000000f, 0.000000f, 0.000000f, 1.000000f, 0.000000f,
- };
- const float JPEG_rgb_to_yuv[] = {
- 0.299000f, 0.587000f, 0.114000f, 0.000000f, 0.000000f,
- -0.168736f, -0.331264f, 0.500000f, 0.000000f, 0.501961f,
- 0.500000f, -0.418688f, -0.081312f, 0.000000f, 0.501961f,
- 0.000000f, 0.000000f, 0.000000f, 1.000000f, 0.000000f,
- };
- const float JPEG_yuv_to_rgb[] = {
- 1.000000f, 0.000000f, 1.402000f, 0.000000f, -0.703749f,
- 1.000000f, -0.344136f, -0.714136f, 0.000000f, 0.531211f,
- 1.000000f, 1.772000f, 0.000000f, 0.000000f, -0.889475f,
- 0.000000f, 0.000000f, 0.000000f, 1.000000f, 0.000000f,
- };
- static_assert(kJPEG_SkYUVColorSpace == 0, "");
- static_assert(kRec601_SkYUVColorSpace == 1, "");
- static_assert(kRec709_SkYUVColorSpace == 2, "");
- const float* yuv_to_rgb_array[] = {
- JPEG_yuv_to_rgb,
- Rec601_yuv_to_rgb,
- Rec709_yuv_to_rgb,
- };
- const float* rgb_to_yuv_array[] = {
- JPEG_rgb_to_yuv,
- Rec601_rgb_to_yuv,
- Rec709_rgb_to_yuv,
- };
- constexpr size_t kSizeOfColorMatrix = 20 * sizeof(float);
- void SkColorMatrix_RGB2YUV(SkYUVColorSpace cs, float m[20]) {
- if ((unsigned)cs < (unsigned)kIdentity_SkYUVColorSpace) {
- memcpy(m, rgb_to_yuv_array[(unsigned)cs], kSizeOfColorMatrix);
- } else {
- memset(m, 0, kSizeOfColorMatrix);
- m[0] = m[6] = m[12] = m[18] = 1;
- }
- }
- void SkColorMatrix_YUV2RGB(SkYUVColorSpace cs, float m[20]) {
- if ((unsigned)cs < (unsigned)kIdentity_SkYUVColorSpace) {
- memcpy(m, yuv_to_rgb_array[(unsigned)cs], kSizeOfColorMatrix);
- } else {
- memset(m, 0, kSizeOfColorMatrix);
- m[0] = m[6] = m[12] = m[18] = 1;
- }
- }
- ///////////////////////////////////////////////////////////////////////////////////////////////////
- // we just drop the alpha rol/col from the colormatrix
- // output is | tr |
- // | 3x3 tg |
- // | tb |
- // | 0 0 0 1 |
- static void colormatrix_to_matrix44(const float src[20], SkMatrix44* dst) {
- for (int r = 0; r < 3; ++r) {
- for (int c = 0; c < 3; ++c) {
- dst->set(r, c, src[r*5 + c]);
- }
- dst->set(r, 3, src[r*5 + 4]);
- }
- dst->set(3, 0, 0);
- dst->set(3, 1, 0);
- dst->set(3, 2, 0);
- dst->set(3, 3, 1);
- }
- // input: ignore the bottom row
- // output: inject identity row/column for alpha
- static void matrix44_to_colormatrix(const SkMatrix44& src, float dst[20]) {
- for (int r = 0; r < 3; ++r) {
- for (int c = 0; c < 3; ++c) {
- dst[r*5 + c] = src.get(r, c);
- }
- dst[r*5 + 3] = 0; // scale alpha
- dst[r*5 + 4] = src.get(r, 3); // translate
- }
- dst[15] = dst[16] = dst[17] = dst[19] = 0;
- dst[18] = 1;
- }
- static void scale3(float m[], float s) {
- for (int i = 0; i < 3; ++i) {
- m[i] *= s;
- }
- }
- namespace {
- struct YUVCoeff {
- float Kr, Kb;
- float Cr, Cb;
- float scaleY, addY;
- float scaleUV;
- };
- } // namespace
- const YUVCoeff gCoeff[] = {
- // kJPEG_SkYUVColorSpace
- { 0.299f, 0.114f, 1/1.772f, 1/1.402f, 1, 0, 1, },
- // kRec601_SkYUVColorSpace
- { 0.299f, 0.114f, 1/1.772f, 1/1.402f, 219/255.f, 16/255.f, 224/255.f, },
- // kRec709_SkYUVColorSpace
- { 0.2126f, 0.0722f, 1/1.8556f, 1/1.5748f, 219/255.f, 16/255.f, 224/255.f, },
- };
- static void make_rgb_to_yuv_matrix(float mx[20], const YUVCoeff& c) {
- const float Kr = c.Kr;
- const float Kb = c.Kb;
- const float Kg = 1.0f - Kr - Kb;
- float m[20] = {
- Kr, Kg, Kb, 0, c.addY,
- -Kr, -Kg, 1-Kb, 0, 128/255.f,
- 1-Kr, -Kg, -Kb, 0, 128/255.f,
- 0, 0, 0, 1, 0,
- };
- memcpy(mx, m, sizeof(m));
- scale3(mx + 0, c.scaleY);
- scale3(mx + 5, c.Cr * c.scaleUV);
- scale3(mx + 10, c.Cb * c.scaleUV);
- }
- static void dump(const float m[20], SkYUVColorSpace cs, bool rgb2yuv) {
- const char* names[] = {
- "JPEG", "Rec601", "Rec709",
- };
- const char* dirnames[] = {
- "yuv_to_rgb", "rgb_to_yuv",
- };
- SkDebugf("const float %s_%s[] = {\n", names[cs], dirnames[rgb2yuv]);
- for (int i = 0; i < 4; ++i) {
- SkDebugf(" ");
- for (int j = 0; j < 5; ++j) {
- SkDebugf(" %9.6ff,", m[i * 5 + j]);
- }
- SkDebugf("\n");
- }
- SkDebugf("};\n");
- }
- // Used to create the prebuilt tables for each colorspace.
- // Don't remove this function, in case we want to recompute those tables in the future.
- void SkColorMatrix_DumpYUVMatrixTables() {
- for (auto cs : {kRec709_SkYUVColorSpace, kRec601_SkYUVColorSpace, kJPEG_SkYUVColorSpace}) {
- float m[20];
- make_rgb_to_yuv_matrix(m, gCoeff[(unsigned)cs]);
- dump(m, cs, true);
- SkMatrix44 m44, im44;
- colormatrix_to_matrix44(m, &m44);
- float im[20];
- #ifdef SK_DEBUG
- // be sure our coversion between matrix44 and colormatrix is perfect
- matrix44_to_colormatrix(m44, im);
- SkASSERT(memcmp(m, im, sizeof(im)) == 0);
- #endif
- SkAssertResult(m44.invert(&im44));
- matrix44_to_colormatrix(im44, im);
- dump(im, cs, false);
- }
- }
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