Image processing and computer vision library in pure C.

• Color images are a flat array of 8-bit per channel RGBA row-major top-to-bottom
• Grayscale images are a flat array of 8-bit GRAY row-major top-to-bottom
• All operations are done on the raw sRGB pixel values
• Minimal usage of macros and preprocessor
• Available as an amalgamation where all code is combined into one file. (Each release includes a flatcv.h and flatcv.c file.)
• No fusing of image transformations
• No multithreading
  You're more likely to process one file per core than one file over multiple cores anyways. Yet, it's still often faster than GraphicsMagick with multiple threads. (Check out the benchmark.)
• No GPU acceleration
• Only uses functions from the C standard library.

FlatCV can either be used as a C library or via its CLI.

The CLI supports edit pipelines which sequentially apply all transformations.

flatcv <input> <comma-separated-edit-pipeline> <output>

As commas aren't special characters in shells, you can write the edit pipeline without quotes. Both variants yield the same result:

flatcv i.jpg 'grayscale, blur 9' o.jpg
flatcv i.jpg grayscale, blur 9 o.jpg

Check out the documentation website for more examples and usage instructions.

Command	Input	Output
flatcv i.jpg grayscale o.jpg
flatcv i.jpg grayscale, blur 9 o.jpg
flatcv i.jpg bw_smooth o.jpg
flatcv i.jpg watershed 0x0 300x200 599x0 o.jpg

#include "flatcv.h"

// Resize an image to half size
unsigned char const * half_size = resize(
    input_width, input_height,
    0.5, 0.5,
    &out_width, &out_height,
    input_data
);

// Do something with the resized image

// Free the allocated memory
free(half_size);