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Diffstat (limited to 'lib/src/icc.cpp')
-rw-r--r-- | lib/src/icc.cpp | 680 |
1 files changed, 680 insertions, 0 deletions
diff --git a/lib/src/icc.cpp b/lib/src/icc.cpp new file mode 100644 index 0000000..b838660 --- /dev/null +++ b/lib/src/icc.cpp @@ -0,0 +1,680 @@ +/* + * Copyright 2022 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include <cstring> + +#include "ultrahdr/ultrahdrcommon.h" +#include "ultrahdr/icc.h" + +namespace ultrahdr { + +static void Matrix3x3_apply(const Matrix3x3* m, float* x) { + float y0 = x[0] * m->vals[0][0] + x[1] * m->vals[0][1] + x[2] * m->vals[0][2]; + float y1 = x[0] * m->vals[1][0] + x[1] * m->vals[1][1] + x[2] * m->vals[1][2]; + float y2 = x[0] * m->vals[2][0] + x[1] * m->vals[2][1] + x[2] * m->vals[2][2]; + x[0] = y0; + x[1] = y1; + x[2] = y2; +} + +bool Matrix3x3_invert(const Matrix3x3* src, Matrix3x3* dst) { + double a00 = src->vals[0][0]; + double a01 = src->vals[1][0]; + double a02 = src->vals[2][0]; + double a10 = src->vals[0][1]; + double a11 = src->vals[1][1]; + double a12 = src->vals[2][1]; + double a20 = src->vals[0][2]; + double a21 = src->vals[1][2]; + double a22 = src->vals[2][2]; + + double b0 = a00 * a11 - a01 * a10; + double b1 = a00 * a12 - a02 * a10; + double b2 = a01 * a12 - a02 * a11; + double b3 = a20; + double b4 = a21; + double b5 = a22; + + double determinant = b0 * b5 - b1 * b4 + b2 * b3; + + if (determinant == 0) { + return false; + } + + double invdet = 1.0 / determinant; + if (invdet > +FLT_MAX || invdet < -FLT_MAX || !isfinitef_((float)invdet)) { + return false; + } + + b0 *= invdet; + b1 *= invdet; + b2 *= invdet; + b3 *= invdet; + b4 *= invdet; + b5 *= invdet; + + dst->vals[0][0] = (float)(a11 * b5 - a12 * b4); + dst->vals[1][0] = (float)(a02 * b4 - a01 * b5); + dst->vals[2][0] = (float)(+b2); + dst->vals[0][1] = (float)(a12 * b3 - a10 * b5); + dst->vals[1][1] = (float)(a00 * b5 - a02 * b3); + dst->vals[2][1] = (float)(-b1); + dst->vals[0][2] = (float)(a10 * b4 - a11 * b3); + dst->vals[1][2] = (float)(a01 * b3 - a00 * b4); + dst->vals[2][2] = (float)(+b0); + + for (int r = 0; r < 3; ++r) + for (int c = 0; c < 3; ++c) { + if (!isfinitef_(dst->vals[r][c])) { + return false; + } + } + return true; +} + +static Matrix3x3 Matrix3x3_concat(const Matrix3x3* A, const Matrix3x3* B) { + Matrix3x3 m = {{{0, 0, 0}, {0, 0, 0}, {0, 0, 0}}}; + for (int r = 0; r < 3; r++) + for (int c = 0; c < 3; c++) { + m.vals[r][c] = A->vals[r][0] * B->vals[0][c] + A->vals[r][1] * B->vals[1][c] + + A->vals[r][2] * B->vals[2][c]; + } + return m; +} + +static void float_XYZD50_to_grid16_lab(const float* xyz_float, uint8_t* grid16_lab) { + float v[3] = { + xyz_float[0] / kD50_x, + xyz_float[1] / kD50_y, + xyz_float[2] / kD50_z, + }; + for (size_t i = 0; i < 3; ++i) { + v[i] = v[i] > 0.008856f ? cbrtf(v[i]) : v[i] * 7.787f + (16 / 116.0f); + } + const float L = v[1] * 116.0f - 16.0f; + const float a = (v[0] - v[1]) * 500.0f; + const float b = (v[1] - v[2]) * 200.0f; + const float Lab_unorm[3] = { + L * (1 / 100.f), + (a + 128.0f) * (1 / 255.0f), + (b + 128.0f) * (1 / 255.0f), + }; + // This will encode L=1 as 0xFFFF. This matches how skcms will interpret the + // table, but the spec appears to indicate that the value should be 0xFF00. + // https://crbug.com/skia/13807 + for (size_t i = 0; i < 3; ++i) { + reinterpret_cast<uint16_t*>(grid16_lab)[i] = + Endian_SwapBE16(float_round_to_unorm16(Lab_unorm[i])); + } +} + +std::string IccHelper::get_desc_string(const ultrahdr_transfer_function tf, + const ultrahdr_color_gamut gamut) { + std::string result; + switch (gamut) { + case ULTRAHDR_COLORGAMUT_BT709: + result += "sRGB"; + break; + case ULTRAHDR_COLORGAMUT_P3: + result += "Display P3"; + break; + case ULTRAHDR_COLORGAMUT_BT2100: + result += "Rec2020"; + break; + default: + result += "Unknown"; + break; + } + result += " Gamut with "; + switch (tf) { + case ULTRAHDR_TF_SRGB: + result += "sRGB"; + break; + case ULTRAHDR_TF_LINEAR: + result += "Linear"; + break; + case ULTRAHDR_TF_PQ: + result += "PQ"; + break; + case ULTRAHDR_TF_HLG: + result += "HLG"; + break; + default: + result += "Unknown"; + break; + } + result += " Transfer"; + return result; +} + +std::shared_ptr<DataStruct> IccHelper::write_text_tag(const char* text) { + uint32_t text_length = strlen(text); + uint32_t header[] = { + Endian_SwapBE32(kTAG_TextType), // Type signature + 0, // Reserved + Endian_SwapBE32(1), // Number of records + Endian_SwapBE32(12), // Record size (must be 12) + Endian_SwapBE32(SetFourByteTag('e', 'n', 'U', 'S')), // English USA + Endian_SwapBE32(2 * text_length), // Length of string in bytes + Endian_SwapBE32(28), // Offset of string + }; + + uint32_t total_length = text_length * 2 + sizeof(header); + total_length = (((total_length + 2) >> 2) << 2); // 4 aligned + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); + + if (!dataStruct->write(header, sizeof(header))) { + ALOGE("write_text_tag(): error in writing data"); + return dataStruct; + } + + for (size_t i = 0; i < text_length; i++) { + // Convert ASCII to big-endian UTF-16. + dataStruct->write8(0); + dataStruct->write8(text[i]); + } + + return dataStruct; +} + +std::shared_ptr<DataStruct> IccHelper::write_xyz_tag(float x, float y, float z) { + uint32_t data[] = { + Endian_SwapBE32(kXYZ_PCSSpace), + 0, + static_cast<uint32_t>(Endian_SwapBE32(float_round_to_fixed(x))), + static_cast<uint32_t>(Endian_SwapBE32(float_round_to_fixed(y))), + static_cast<uint32_t>(Endian_SwapBE32(float_round_to_fixed(z))), + }; + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(sizeof(data)); + dataStruct->write(&data, sizeof(data)); + return dataStruct; +} + +std::shared_ptr<DataStruct> IccHelper::write_trc_tag(const int table_entries, + const void* table_16) { + int total_length = 4 + 4 + 4 + table_entries * 2; + total_length = (((total_length + 2) >> 2) << 2); // 4 aligned + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); + dataStruct->write32(Endian_SwapBE32(kTAG_CurveType)); // Type + dataStruct->write32(0); // Reserved + dataStruct->write32(Endian_SwapBE32(table_entries)); // Value count + for (int i = 0; i < table_entries; ++i) { + uint16_t value = reinterpret_cast<const uint16_t*>(table_16)[i]; + dataStruct->write16(value); + } + return dataStruct; +} + +std::shared_ptr<DataStruct> IccHelper::write_trc_tag(const TransferFunction& fn) { + if (fn.a == 1.f && fn.b == 0.f && fn.c == 0.f && fn.d == 0.f && fn.e == 0.f && fn.f == 0.f) { + int total_length = 16; + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); + dataStruct->write32(Endian_SwapBE32(kTAG_ParaCurveType)); // Type + dataStruct->write32(0); // Reserved + dataStruct->write32(Endian_SwapBE16(kExponential_ParaCurveType)); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.g))); + return dataStruct; + } + + int total_length = 40; + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); + dataStruct->write32(Endian_SwapBE32(kTAG_ParaCurveType)); // Type + dataStruct->write32(0); // Reserved + dataStruct->write32(Endian_SwapBE16(kGABCDEF_ParaCurveType)); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.g))); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.a))); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.b))); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.c))); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.d))); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.e))); + dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.f))); + return dataStruct; +} + +float IccHelper::compute_tone_map_gain(const ultrahdr_transfer_function tf, float L) { + if (L <= 0.f) { + return 1.f; + } + if (tf == ULTRAHDR_TF_PQ) { + // The PQ transfer function will map to the range [0, 1]. Linearly scale + // it up to the range [0, 10,000/203]. We will then tone map that back + // down to [0, 1]. + constexpr float kInputMaxLuminance = 10000 / 203.f; + constexpr float kOutputMaxLuminance = 1.0; + L *= kInputMaxLuminance; + + // Compute the tone map gain which will tone map from 10,000/203 to 1.0. + constexpr float kToneMapA = kOutputMaxLuminance / (kInputMaxLuminance * kInputMaxLuminance); + constexpr float kToneMapB = 1.f / kOutputMaxLuminance; + return kInputMaxLuminance * (1.f + kToneMapA * L) / (1.f + kToneMapB * L); + } + if (tf == ULTRAHDR_TF_HLG) { + // Let Lw be the brightness of the display in nits. + constexpr float Lw = 203.f; + const float gamma = 1.2f + 0.42f * std::log(Lw / 1000.f) / std::log(10.f); + return std::pow(L, gamma - 1.f); + } + return 1.f; +} + +std::shared_ptr<DataStruct> IccHelper::write_cicp_tag(uint32_t color_primaries, + uint32_t transfer_characteristics) { + int total_length = 12; // 4 + 4 + 1 + 1 + 1 + 1 + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); + dataStruct->write32(Endian_SwapBE32(kTAG_cicp)); // Type signature + dataStruct->write32(0); // Reserved + dataStruct->write8(color_primaries); // Color primaries + dataStruct->write8(transfer_characteristics); // Transfer characteristics + dataStruct->write8(0); // RGB matrix + dataStruct->write8(1); // Full range + return dataStruct; +} + +void IccHelper::compute_lut_entry(const Matrix3x3& src_to_XYZD50, float rgb[3]) { + // Compute the matrices to convert from source to Rec2020, and from Rec2020 to XYZD50. + Matrix3x3 src_to_rec2020; + const Matrix3x3 rec2020_to_XYZD50 = kRec2020; + { + Matrix3x3 XYZD50_to_rec2020; + Matrix3x3_invert(&rec2020_to_XYZD50, &XYZD50_to_rec2020); + src_to_rec2020 = Matrix3x3_concat(&XYZD50_to_rec2020, &src_to_XYZD50); + } + + // Convert the source signal to linear. + for (size_t i = 0; i < kNumChannels; ++i) { + rgb[i] = pqOetf(rgb[i]); + } + + // Convert source gamut to Rec2020. + Matrix3x3_apply(&src_to_rec2020, rgb); + + // Compute the luminance of the signal. + float L = bt2100Luminance({{{rgb[0], rgb[1], rgb[2]}}}); + + // Compute the tone map gain based on the luminance. + float tone_map_gain = compute_tone_map_gain(ULTRAHDR_TF_PQ, L); + + // Apply the tone map gain. + for (size_t i = 0; i < kNumChannels; ++i) { + rgb[i] *= tone_map_gain; + } + + // Convert from Rec2020-linear to XYZD50. + Matrix3x3_apply(&rec2020_to_XYZD50, rgb); +} + +std::shared_ptr<DataStruct> IccHelper::write_clut(const uint8_t* grid_points, + const uint8_t* grid_16) { + uint32_t value_count = kNumChannels; + for (uint32_t i = 0; i < kNumChannels; ++i) { + value_count *= grid_points[i]; + } + + int total_length = 20 + 2 * value_count; + total_length = (((total_length + 2) >> 2) << 2); // 4 aligned + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); + + for (size_t i = 0; i < 16; ++i) { + dataStruct->write8(i < kNumChannels ? grid_points[i] : 0); // Grid size + } + dataStruct->write8(2); // Grid byte width (always 16-bit) + dataStruct->write8(0); // Reserved + dataStruct->write8(0); // Reserved + dataStruct->write8(0); // Reserved + + for (uint32_t i = 0; i < value_count; ++i) { + uint16_t value = reinterpret_cast<const uint16_t*>(grid_16)[i]; + dataStruct->write16(value); + } + + return dataStruct; +} + +std::shared_ptr<DataStruct> IccHelper::write_mAB_or_mBA_tag(uint32_t type, bool has_a_curves, + const uint8_t* grid_points, + const uint8_t* grid_16) { + const size_t b_curves_offset = 32; + std::shared_ptr<DataStruct> b_curves_data[kNumChannels]; + std::shared_ptr<DataStruct> a_curves_data[kNumChannels]; + size_t clut_offset = 0; + std::shared_ptr<DataStruct> clut; + size_t a_curves_offset = 0; + + // The "B" curve is required. + for (size_t i = 0; i < kNumChannels; ++i) { + b_curves_data[i] = write_trc_tag(kLinear_TransFun); + } + + // The "A" curve and CLUT are optional. + if (has_a_curves) { + clut_offset = b_curves_offset; + for (size_t i = 0; i < kNumChannels; ++i) { + clut_offset += b_curves_data[i]->getLength(); + } + clut = write_clut(grid_points, grid_16); + + a_curves_offset = clut_offset + clut->getLength(); + for (size_t i = 0; i < kNumChannels; ++i) { + a_curves_data[i] = write_trc_tag(kLinear_TransFun); + } + } + + int total_length = b_curves_offset; + for (size_t i = 0; i < kNumChannels; ++i) { + total_length += b_curves_data[i]->getLength(); + } + if (has_a_curves) { + total_length += clut->getLength(); + for (size_t i = 0; i < kNumChannels; ++i) { + total_length += a_curves_data[i]->getLength(); + } + } + std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(total_length); + dataStruct->write32(Endian_SwapBE32(type)); // Type signature + dataStruct->write32(0); // Reserved + dataStruct->write8(kNumChannels); // Input channels + dataStruct->write8(kNumChannels); // Output channels + dataStruct->write16(0); // Reserved + dataStruct->write32(Endian_SwapBE32(b_curves_offset)); // B curve offset + dataStruct->write32(Endian_SwapBE32(0)); // Matrix offset (ignored) + dataStruct->write32(Endian_SwapBE32(0)); // M curve offset (ignored) + dataStruct->write32(Endian_SwapBE32(clut_offset)); // CLUT offset + dataStruct->write32(Endian_SwapBE32(a_curves_offset)); // A curve offset + for (size_t i = 0; i < kNumChannels; ++i) { + if (dataStruct->write(b_curves_data[i]->getData(), b_curves_data[i]->getLength())) { + return dataStruct; + } + } + if (has_a_curves) { + dataStruct->write(clut->getData(), clut->getLength()); + for (size_t i = 0; i < kNumChannels; ++i) { + dataStruct->write(a_curves_data[i]->getData(), a_curves_data[i]->getLength()); + } + } + return dataStruct; +} + +std::shared_ptr<DataStruct> IccHelper::writeIccProfile(ultrahdr_transfer_function tf, + ultrahdr_color_gamut gamut) { + ICCHeader header; + + std::vector<std::pair<uint32_t, std::shared_ptr<DataStruct>>> tags; + + // Compute profile description tag + std::string desc = get_desc_string(tf, gamut); + + tags.emplace_back(kTAG_desc, write_text_tag(desc.c_str())); + + Matrix3x3 toXYZD50; + switch (gamut) { + case ULTRAHDR_COLORGAMUT_BT709: + toXYZD50 = kSRGB; + break; + case ULTRAHDR_COLORGAMUT_P3: + toXYZD50 = kDisplayP3; + break; + case ULTRAHDR_COLORGAMUT_BT2100: + toXYZD50 = kRec2020; + break; + default: + // Should not fall here. + return nullptr; + } + + // Compute primaries. + { + tags.emplace_back(kTAG_rXYZ, + write_xyz_tag(toXYZD50.vals[0][0], toXYZD50.vals[1][0], toXYZD50.vals[2][0])); + tags.emplace_back(kTAG_gXYZ, + write_xyz_tag(toXYZD50.vals[0][1], toXYZD50.vals[1][1], toXYZD50.vals[2][1])); + tags.emplace_back(kTAG_bXYZ, + write_xyz_tag(toXYZD50.vals[0][2], toXYZD50.vals[1][2], toXYZD50.vals[2][2])); + } + + // Compute white point tag (must be D50) + tags.emplace_back(kTAG_wtpt, write_xyz_tag(kD50_x, kD50_y, kD50_z)); + + // Compute transfer curves. + if (tf != ULTRAHDR_TF_PQ) { + if (tf == ULTRAHDR_TF_HLG) { + std::vector<uint8_t> trc_table; + trc_table.resize(kTrcTableSize * 2); + for (uint32_t i = 0; i < kTrcTableSize; ++i) { + float x = i / (kTrcTableSize - 1.f); + float y = hlgOetf(x); + y *= compute_tone_map_gain(tf, y); + float_to_table16(y, &trc_table[2 * i]); + } + + tags.emplace_back(kTAG_rTRC, + write_trc_tag(kTrcTableSize, reinterpret_cast<uint8_t*>(trc_table.data()))); + tags.emplace_back(kTAG_gTRC, + write_trc_tag(kTrcTableSize, reinterpret_cast<uint8_t*>(trc_table.data()))); + tags.emplace_back(kTAG_bTRC, + write_trc_tag(kTrcTableSize, reinterpret_cast<uint8_t*>(trc_table.data()))); + } else { + tags.emplace_back(kTAG_rTRC, write_trc_tag(kSRGB_TransFun)); + tags.emplace_back(kTAG_gTRC, write_trc_tag(kSRGB_TransFun)); + tags.emplace_back(kTAG_bTRC, write_trc_tag(kSRGB_TransFun)); + } + } + + // Compute CICP. + if (tf == ULTRAHDR_TF_HLG || tf == ULTRAHDR_TF_PQ) { + // The CICP tag is present in ICC 4.4, so update the header's version. + header.version = Endian_SwapBE32(0x04400000); + + uint32_t color_primaries = 0; + if (gamut == ULTRAHDR_COLORGAMUT_BT709) { + color_primaries = kCICPPrimariesSRGB; + } else if (gamut == ULTRAHDR_COLORGAMUT_P3) { + color_primaries = kCICPPrimariesP3; + } + + uint32_t transfer_characteristics = 0; + if (tf == ULTRAHDR_TF_SRGB) { + transfer_characteristics = kCICPTrfnSRGB; + } else if (tf == ULTRAHDR_TF_LINEAR) { + transfer_characteristics = kCICPTrfnLinear; + } else if (tf == ULTRAHDR_TF_PQ) { + transfer_characteristics = kCICPTrfnPQ; + } else if (tf == ULTRAHDR_TF_HLG) { + transfer_characteristics = kCICPTrfnHLG; + } + tags.emplace_back(kTAG_cicp, write_cicp_tag(color_primaries, transfer_characteristics)); + } + + // Compute A2B0. + if (tf == ULTRAHDR_TF_PQ) { + std::vector<uint8_t> a2b_grid; + a2b_grid.resize(kGridSize * kGridSize * kGridSize * kNumChannels * 2); + size_t a2b_grid_index = 0; + for (uint32_t r_index = 0; r_index < kGridSize; ++r_index) { + for (uint32_t g_index = 0; g_index < kGridSize; ++g_index) { + for (uint32_t b_index = 0; b_index < kGridSize; ++b_index) { + float rgb[3] = { + r_index / (kGridSize - 1.f), + g_index / (kGridSize - 1.f), + b_index / (kGridSize - 1.f), + }; + compute_lut_entry(toXYZD50, rgb); + float_XYZD50_to_grid16_lab(rgb, &a2b_grid[a2b_grid_index]); + a2b_grid_index += 6; + } + } + } + const uint8_t* grid_16 = reinterpret_cast<const uint8_t*>(a2b_grid.data()); + + uint8_t grid_points[kNumChannels]; + for (size_t i = 0; i < kNumChannels; ++i) { + grid_points[i] = kGridSize; + } + + auto a2b_data = write_mAB_or_mBA_tag(kTAG_mABType, + /* has_a_curves */ true, grid_points, grid_16); + tags.emplace_back(kTAG_A2B0, std::move(a2b_data)); + } + + // Compute B2A0. + if (tf == ULTRAHDR_TF_PQ) { + auto b2a_data = write_mAB_or_mBA_tag(kTAG_mBAType, + /* has_a_curves */ false, + /* grid_points */ nullptr, + /* grid_16 */ nullptr); + tags.emplace_back(kTAG_B2A0, std::move(b2a_data)); + } + + // Compute copyright tag + tags.emplace_back(kTAG_cprt, write_text_tag("Google Inc. 2022")); + + // Compute the size of the profile. + size_t tag_data_size = 0; + for (const auto& tag : tags) { + tag_data_size += tag.second->getLength(); + } + size_t tag_table_size = kICCTagTableEntrySize * tags.size(); + size_t profile_size = kICCHeaderSize + tag_table_size + tag_data_size; + + std::shared_ptr<DataStruct> dataStruct = + std::make_shared<DataStruct>(profile_size + kICCIdentifierSize); + + // Write identifier, chunk count, and chunk ID + if (!dataStruct->write(kICCIdentifier, sizeof(kICCIdentifier)) || !dataStruct->write8(1) || + !dataStruct->write8(1)) { + ALOGE("writeIccProfile(): error in identifier"); + return dataStruct; + } + + // Write the header. + header.data_color_space = Endian_SwapBE32(Signature_RGB); + header.pcs = Endian_SwapBE32(tf == ULTRAHDR_TF_PQ ? Signature_Lab : Signature_XYZ); + header.size = Endian_SwapBE32(profile_size); + header.tag_count = Endian_SwapBE32(tags.size()); + + if (!dataStruct->write(&header, sizeof(header))) { + ALOGE("writeIccProfile(): error in header"); + return dataStruct; + } + + // Write the tag table. Track the offset and size of the previous tag to + // compute each tag's offset. An empty SkData indicates that the previous + // tag is to be reused. + uint32_t last_tag_offset = sizeof(header) + tag_table_size; + uint32_t last_tag_size = 0; + for (const auto& tag : tags) { + last_tag_offset = last_tag_offset + last_tag_size; + last_tag_size = tag.second->getLength(); + uint32_t tag_table_entry[3] = { + Endian_SwapBE32(tag.first), + Endian_SwapBE32(last_tag_offset), + Endian_SwapBE32(last_tag_size), + }; + if (!dataStruct->write(tag_table_entry, sizeof(tag_table_entry))) { + ALOGE("writeIccProfile(): error in writing tag table"); + return dataStruct; + } + } + + // Write the tags. + for (const auto& tag : tags) { + if (!dataStruct->write(tag.second->getData(), tag.second->getLength())) { + ALOGE("writeIccProfile(): error in writing tags"); + return dataStruct; + } + } + + return dataStruct; +} + +bool IccHelper::tagsEqualToMatrix(const Matrix3x3& matrix, const uint8_t* red_tag, + const uint8_t* green_tag, const uint8_t* blue_tag) { + std::shared_ptr<DataStruct> red_tag_test = + write_xyz_tag(matrix.vals[0][0], matrix.vals[1][0], matrix.vals[2][0]); + std::shared_ptr<DataStruct> green_tag_test = + write_xyz_tag(matrix.vals[0][1], matrix.vals[1][1], matrix.vals[2][1]); + std::shared_ptr<DataStruct> blue_tag_test = + write_xyz_tag(matrix.vals[0][2], matrix.vals[1][2], matrix.vals[2][2]); + return memcmp(red_tag, red_tag_test->getData(), kColorantTagSize) == 0 && + memcmp(green_tag, green_tag_test->getData(), kColorantTagSize) == 0 && + memcmp(blue_tag, blue_tag_test->getData(), kColorantTagSize) == 0; +} + +ultrahdr_color_gamut IccHelper::readIccColorGamut(void* icc_data, size_t icc_size) { + // Each tag table entry consists of 3 fields of 4 bytes each. + static const size_t kTagTableEntrySize = 12; + + if (icc_data == nullptr || icc_size < sizeof(ICCHeader) + kICCIdentifierSize) { + return ULTRAHDR_COLORGAMUT_UNSPECIFIED; + } + + if (memcmp(icc_data, kICCIdentifier, sizeof(kICCIdentifier)) != 0) { + return ULTRAHDR_COLORGAMUT_UNSPECIFIED; + } + + uint8_t* icc_bytes = reinterpret_cast<uint8_t*>(icc_data) + kICCIdentifierSize; + + ICCHeader* header = reinterpret_cast<ICCHeader*>(icc_bytes); + + // Use 0 to indicate not found, since offsets are always relative to start + // of ICC data and therefore a tag offset of zero would never be valid. + size_t red_primary_offset = 0, green_primary_offset = 0, blue_primary_offset = 0; + size_t red_primary_size = 0, green_primary_size = 0, blue_primary_size = 0; + for (size_t tag_idx = 0; tag_idx < Endian_SwapBE32(header->tag_count); ++tag_idx) { + uint32_t* tag_entry_start = + reinterpret_cast<uint32_t*>(icc_bytes + sizeof(ICCHeader) + tag_idx * kTagTableEntrySize); + // first 4 bytes are the tag signature, next 4 bytes are the tag offset, + // last 4 bytes are the tag length in bytes. + if (red_primary_offset == 0 && *tag_entry_start == Endian_SwapBE32(kTAG_rXYZ)) { + red_primary_offset = Endian_SwapBE32(*(tag_entry_start + 1)); + red_primary_size = Endian_SwapBE32(*(tag_entry_start + 2)); + } else if (green_primary_offset == 0 && *tag_entry_start == Endian_SwapBE32(kTAG_gXYZ)) { + green_primary_offset = Endian_SwapBE32(*(tag_entry_start + 1)); + green_primary_size = Endian_SwapBE32(*(tag_entry_start + 2)); + } else if (blue_primary_offset == 0 && *tag_entry_start == Endian_SwapBE32(kTAG_bXYZ)) { + blue_primary_offset = Endian_SwapBE32(*(tag_entry_start + 1)); + blue_primary_size = Endian_SwapBE32(*(tag_entry_start + 2)); + } + } + + if (red_primary_offset == 0 || red_primary_size != kColorantTagSize || + kICCIdentifierSize + red_primary_offset + red_primary_size > icc_size || + green_primary_offset == 0 || green_primary_size != kColorantTagSize || + kICCIdentifierSize + green_primary_offset + green_primary_size > icc_size || + blue_primary_offset == 0 || blue_primary_size != kColorantTagSize || + kICCIdentifierSize + blue_primary_offset + blue_primary_size > icc_size) { + return ULTRAHDR_COLORGAMUT_UNSPECIFIED; + } + + uint8_t* red_tag = icc_bytes + red_primary_offset; + uint8_t* green_tag = icc_bytes + green_primary_offset; + uint8_t* blue_tag = icc_bytes + blue_primary_offset; + + // Serialize tags as we do on encode and compare what we find to that to + // determine the gamut (since we don't have a need yet for full deserialize). + if (tagsEqualToMatrix(kSRGB, red_tag, green_tag, blue_tag)) { + return ULTRAHDR_COLORGAMUT_BT709; + } else if (tagsEqualToMatrix(kDisplayP3, red_tag, green_tag, blue_tag)) { + return ULTRAHDR_COLORGAMUT_P3; + } else if (tagsEqualToMatrix(kRec2020, red_tag, green_tag, blue_tag)) { + return ULTRAHDR_COLORGAMUT_BT2100; + } + + // Didn't find a match to one of the profiles we write; indicate the gamut + // is unspecified since we don't understand it. + return ULTRAHDR_COLORGAMUT_UNSPECIFIED; +} + +} // namespace ultrahdr |