/* * 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); } }