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// Copyright (c) the JPEG XL Project Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include <jxl/cms.h>
#include <cstddef>
#include <utility>
#include "lib/jxl/base/compiler_specific.h"
#include "lib/jxl/base/matrix_ops.h"
#include "lib/jxl/cms/opsin_params.h"
#include "lib/jxl/dec_xyb.h"
#include "lib/jxl/enc_xyb.h"
#include "lib/jxl/image.h"
#include "lib/jxl/image_bundle.h"
#include "lib/jxl/image_metadata.h"
#include "lib/jxl/opsin_params.h"
#include "lib/jxl/testing.h"
namespace jxl {
namespace {
// Convert a single linear sRGB color to xyb, using the exact image conversion
// procedure that jpeg xl uses.
void LinearSrgbToOpsin(float rgb_r, float rgb_g, float rgb_b,
float* JXL_RESTRICT xyb_x, float* JXL_RESTRICT xyb_y,
float* JXL_RESTRICT xyb_b) {
JXL_ASSIGN_OR_DIE(Image3F linear, Image3F::Create(1, 1));
linear.PlaneRow(0, 0)[0] = rgb_r;
linear.PlaneRow(1, 0)[0] = rgb_g;
linear.PlaneRow(2, 0)[0] = rgb_b;
ImageMetadata metadata;
metadata.SetFloat32Samples();
metadata.color_encoding = ColorEncoding::LinearSRGB();
ImageBundle ib(&metadata);
ib.SetFromImage(std::move(linear), metadata.color_encoding);
JXL_ASSIGN_OR_DIE(Image3F opsin, Image3F::Create(1, 1));
(void)ToXYB(ib, /*pool=*/nullptr, &opsin, *JxlGetDefaultCms());
*xyb_x = opsin.PlaneRow(0, 0)[0];
*xyb_y = opsin.PlaneRow(1, 0)[0];
*xyb_b = opsin.PlaneRow(2, 0)[0];
}
// Convert a single XYB color to linear sRGB, using the exact image conversion
// procedure that jpeg xl uses.
void OpsinToLinearSrgb(float xyb_x, float xyb_y, float xyb_b,
float* JXL_RESTRICT rgb_r, float* JXL_RESTRICT rgb_g,
float* JXL_RESTRICT rgb_b) {
JXL_ASSIGN_OR_DIE(Image3F opsin, Image3F::Create(1, 1));
opsin.PlaneRow(0, 0)[0] = xyb_x;
opsin.PlaneRow(1, 0)[0] = xyb_y;
opsin.PlaneRow(2, 0)[0] = xyb_b;
JXL_ASSIGN_OR_DIE(Image3F linear, Image3F::Create(1, 1));
OpsinParams opsin_params;
opsin_params.Init(/*intensity_target=*/255.0f);
OpsinToLinear(opsin, Rect(opsin), nullptr, &linear, opsin_params);
*rgb_r = linear.PlaneRow(0, 0)[0];
*rgb_g = linear.PlaneRow(1, 0)[0];
*rgb_b = linear.PlaneRow(2, 0)[0];
}
void OpsinRoundtripTestRGB(float r, float g, float b) {
float xyb_x;
float xyb_y;
float xyb_b;
LinearSrgbToOpsin(r, g, b, &xyb_x, &xyb_y, &xyb_b);
float r2;
float g2;
float b2;
OpsinToLinearSrgb(xyb_x, xyb_y, xyb_b, &r2, &g2, &b2);
EXPECT_NEAR(r, r2, 1e-3);
EXPECT_NEAR(g, g2, 1e-3);
EXPECT_NEAR(b, b2, 1e-3);
}
TEST(OpsinImageTest, VerifyOpsinAbsorbanceInverseMatrix) {
Matrix3x3 matrix; // writable copy
matrix = GetOpsinAbsorbanceInverseMatrix();
EXPECT_TRUE(Inv3x3Matrix(matrix));
for (int j = 0; j < 3; j++) {
for (int i = 0; i < 3; i++) {
EXPECT_NEAR(matrix[j][i], jxl::cms::kOpsinAbsorbanceMatrix[j][i], 1e-6);
}
}
}
TEST(OpsinImageTest, OpsinRoundtrip) {
OpsinRoundtripTestRGB(0, 0, 0);
OpsinRoundtripTestRGB(1. / 255, 1. / 255, 1. / 255);
OpsinRoundtripTestRGB(128. / 255, 128. / 255, 128. / 255);
OpsinRoundtripTestRGB(1, 1, 1);
OpsinRoundtripTestRGB(0, 0, 1. / 255);
OpsinRoundtripTestRGB(0, 0, 128. / 255);
OpsinRoundtripTestRGB(0, 0, 1);
OpsinRoundtripTestRGB(0, 1. / 255, 0);
OpsinRoundtripTestRGB(0, 128. / 255, 0);
OpsinRoundtripTestRGB(0, 1, 0);
OpsinRoundtripTestRGB(1. / 255, 0, 0);
OpsinRoundtripTestRGB(128. / 255, 0, 0);
OpsinRoundtripTestRGB(1, 0, 0);
}
TEST(OpsinImageTest, VerifyZero) {
// Test that black color (zero energy) is 0,0,0 in xyb.
float x;
float y;
float b;
LinearSrgbToOpsin(0, 0, 0, &x, &y, &b);
EXPECT_NEAR(0, x, 1e-9);
EXPECT_NEAR(0, y, 1e-7);
EXPECT_NEAR(0, b, 1e-7);
}
TEST(OpsinImageTest, VerifyGray) {
// Test that grayscale colors have a fixed y/b ratio and x==0.
for (size_t i = 1; i < 255; i++) {
float x;
float y;
float b;
LinearSrgbToOpsin(i / 255., i / 255., i / 255., &x, &y, &b);
EXPECT_NEAR(0, x, 1e-6);
EXPECT_NEAR(jxl::cms::kYToBRatio, b / y, 3e-5);
}
}
} // namespace
} // namespace jxl
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