a-sixel

A-Sixel library for encoding sixel images.

Basic Usage

use a_sixel::ADUSixelEncoder;
use image::RgbImage;

let img = RgbImage::new(100, 100);
println!("{}", <ADUSixelEncoder>::encode(&img));

Choosing an Encoder

• I want fast encoding with good quality:
  • Use [ADUSixelEncoder]
  • [BitSixelEncoder] can also produce pretty good results for 256 colors depending on the image while being over 10x faster.
• I'm time constrained:
  • Use [ADUSixelEncoder] or [BitSixelEncoder]. You can customize ADU by lowering the STEPS parameter to run faster if necessary while still getting good results.
• I'm really time constrained and can sacrifice a little quality:
  • Use [BitSixelEncoder<NoDither>].
• I want high quality encoding, and don't mind a bit more computation:

  • Use [FocalSixelEncoder].

  • This matters a lot less if you're not crunching the palette down below 256 colors.

  • Note that this an experimental encoder. It will likely produce better results than just [ADUSixelEncoder], but it may not always do so. On the test images, for my personal preferences, I think it's slightly better - particularly at small palette sizes.

    Under the hood, it is a modified version of the ADUSixelEncoder that uses a weighted selection algorithm for its sample pixels. These weights are determined based on saliency maps and measures of statistical noise in the image.

    In addition to the weighted selection, the distance metric used to determine which cluster to place a pixel into also incorporates the weight. Similar pixels with different weights will be nudged towards clusters with similar weights. This is a mild effect, but it seems to improve things over basic clustering when there are a lot of similar colors in an image.

License: MIT OR Apache-2.0