Quite Okay Image (QOI) Library

Welcome to the Quite Okay Image (QOI) library! This is a simple and fast C implementation of the QOI image format — a cool lossless image compression format that’s easy to use and super quick to encode and decode.

This library was written by me as a fun challenge in around 4 hours -- Time well spent!

Overview

The magic happens in qoi.c and qoi.h. These files let you load and save QOI images with support for both RGB and RGBA pixel formats.

Features

• Lossless image compression and decompression with the QOI format.
• Works with images that have 3 channels (RGB) or 4 channels (RGBA).
• Simple and straightforward API for loading and saving images.
• Minimal dependencies — just plain old C.

API Reference

This header file defines the main data structures and functions:

• QOI_EResult: Enum for error and status codes you might get back.
• QOI_ImageStruct: Holds your image data, dimensions, channels, and colorspace info.
• Functions:
  • qoi_load_from_file(const char *path, QOI_ImageStruct *image): Loads a QOI image from a file.
  • qoi_store_to_file(const char *path, QOI_ImageStruct *image): Saves your image data to a QOI file.
  • qoi_image_free(QOI_ImageStruct image): Frees the memory used by the image pixels.

How to Use

1. Include qoi.h in your project.
2. Call qoi_load_from_file to load a QOI image.
3. Work with the raw pixel data via the pixels pointer in QOI_ImageStruct.
4. Modify or use the image data however you want.
5. Save your changes with qoi_store_to_file.
6. When you’re done, free the pixel data with qoi_image_free.

Example

#include "qoi.h"
#include <stdio.h>

int main() {
    QOI_ImageStruct image;
    if (qoi_load_from_file("input.qoi", &image) != QOI_OK) {
        printf("Oops! Couldn’t load the image.\n");
        return 1;
    }

    // Do your image magic here

    if (qoi_store_to_file("output.qoi", &image) != QOI_OK) {
        printf("Oops! Couldn’t save the image.\n");
    }

    qoi_image_free(image);
    return 0;
}

Plans for the Future

• Add load/store to memory functionality
• Add an ability to set custom callbacks for FS access

License

This project is under the MIT License. Software provided AS IS, without any warranties.

References

• Check out the QOI format spec here: https://qoiformat.org/