KO | EN

GitLite

Minimalist Open Source Repository Search Engine

gitlite — search

#dsh #dsh-plugin #codex #typescript #developer-tools #ai-agents #deepseek-harness #claude-code #ai-agent #cli #react #mcp

color-util

★ 108 Open GitHub ↗

A header-only C++11 library for colors; color space converters for RGB, HSL, XYZ, Lab, etc. and perceptual color difference calculators such as CIEDE2000

// repository documentation

Was this content helpful?

★ 0 (0 ratings)

# color-util

![macOS](https://github.com/yuki-koyama/color-util/workflows/macOS/badge.svg)
![Ubuntu](https://github.com/yuki-koyama/color-util/workflows/Ubuntu/badge.svg)

A header-only C++11 library for handling colors, including color space converters between RGB, XYZ, Lab, etc. and color difference calculators such as CIEDE2000.

## Color Space Convertors

- Conversion between RGB and HSL
  - `color-util/RGB_to_HSL.hpp`
  - `color-util/HSL_to_RGB.hpp`
- Conversion between sRGB and CIEXYZ (D65)
  - `color-util/RGB_to_XYZ.hpp`
  - `color-util/XYZ_to_RGB.hpp`
- Conversion between CIEXYZ (D65) and CIELAB (a.k.a. CIE L\*a\*b\*) (D65)
  - `color-util/XYZ_to_Lab.hpp`
  - `color-util/Lab_to_XYZ.hpp`

## Color Difference Calculators

### CIE76

Given two CIELAB colors, `calculate_CIE76` calculates a *perceptual* difference between these two colors based on a metric called CIE76. This function is defined in `color-util/CIE76.hpp`.

It is known that this metric is not perceptually uniform especially with saturated colors. In general, CIEDE2000 is considered as a better choice.

### CIEDE2000

Given two CIELAB colors, `calculate_CIEDE2000` calculates a *perceptual* difference between these two colors based on a metric called CIEDE2000. This function is defined in `color-util/CIEDE2000.hpp`.

The correctness of the implementation is verified through the test dataset provided by Gaurav Sharma <https://hajim.rochester.edu/ece/sites/gsharma/ciede2000/>.

## Dependency

- Eigen <http://eigen.tuxfamily.org/>

## Installation

color-util is a *header-only* library, so it can be used by just copying the directory named `color-util` to the `include` directory of the target project. No need to build it in advance.

For CMake <https://cmake.org/> users, this repository includes `CMakeLists.txt`; it can be installed by
```bash
cmake [PATH_TO_THIS_REPOSITORY] -DCMAKE_INSTALL_PREFIX=[PATH_TO_INSTALL_DIRECTORY]
make install
```
Alternatively, if the target project is also managed by CMake, the `ExternalProject_Add` command is also useful.

## Example

Here is an example code for calculating a perceptual distance of two sRGB colors. First, include necessary headers:
```cpp
#include <color-util/RGB_to_XYZ.hpp>
#include <color-util/XYZ_to_Lab.hpp>
#include <color-util/CIEDE2000.hpp>
```
Define the target colors in sRGB:
```cpp
colorutil::RGB rgb_color_1(200.0 / 255.0, 100.0 / 255.0, 20.0 / 200.0);
colorutil::RGB rgb_color_2(100.0 / 255.0, 200.0 / 255.0, 50.0 / 200.0);
```
CIEDE2000 requires CIELAB colors as input, so convert them to CIELAB via CIEXYZ:
```cpp
colorutil::XYZ xyz_color_1 = colorutil::convert_RGB_to_XYZ(rgb_color_1);
colorutil::XYZ xyz_color_2 = colorutil::convert_RGB_to_XYZ(rgb_color_2);
colorutil::Lab lab_color_1 = colorutil::convert_XYZ_to_Lab(xyz_color_1);
colorutil::Lab lab_color_2 = colorutil::convert_XYZ_to_Lab(xyz_color_2);
```
Finally, calculate the perceptual distance of the two colors:
```cpp
double difference = colorutil::calculate_CIEDE2000(lab_color_1, lab_color_2);
```
In this case, it returns `53.8646` as the perceptual distance between the two colors.

## License

MIT License.

## Contribute

Pull requests are welcome.

color-util

Explore Similar Repositories

Was this content helpful?

Recent Feedback

Download README