Laime

A simple ditherer written in C, using stb.

What can it do?

Laime currently supports the following dithering algorithms:

• Atkinson
• Ordered with an 8x8 Bayer matrix
• Floyd-Steinberg

Building

In order to build Laime, you will need a C compiler, and the stb_image.h, stb_image_write.h, and stb_image_resize2.h single header libraries from stb.

On Arch Linux, the entire set of stb libraries is packaged as stb.

# pacman -S stb

Finally, to build Laime, simply run ./build.sh which will call your default C compiler (cc in $PATH).

$ ./build.sh

Usage

^{Here be dragons}

Basic usage:

$ laime --input <path/to/image> --output <path/to/image.png> [OPTIONS]... [--<ditherer>]

Required flags:

• --input <path/to/image>
  • Specifies the input file.
  • Supported formats: JPG, PNG, TGA, BMP, PSD, GIF, HDR, PIC.
• --output <path/to/image.png>
  • specifies the output file
  • the output is always PNG

Optional flags:

• --shades <2-256>
  • Specifies the number of values allowed for each channel between and including 0 and 255
• --channels <0-4>
  • specifies the colour format of the output image as a number of channels
    • 0 - keep the format of the original image
    • 1 - grayscale
    • 2 - grayscale + alpha
    • 3 - RGB
    • 4 - RGBA
• --downsize <factor>
  • specifies a factor by which to downscale the image before dithering
  • the image gets upscaled back by the same factor after dithering
  • this may be desirable to accentuate the dither pattern for some algorithms

Note: when any of the above flags is declared multiple times, only the last instance of each takes effect.

The ditherer may also be specified using one of the following flags:

• --atkinson
• --bayer
• --floyd-steinberg (default if none is specified)

In addition to the above ditherers, you may also choose to use the --no-ditherer flag to only limit the colour space without dithering the image.

Note: if multiple flags to choose a ditherer are used, only the last one to be specified takes effect.