Crate zenquant 

AQ-informed color quantization for indexed image formats.

zenquant reduces truecolor images to 256-color palettes using perceptual masking (butteraugli-inspired AQ weights), OKLab color space, and optional Viterbi DP for run-length–friendly index ordering.

Quick start

use zenquant::{QuantizeConfig, OutputFormat};

let config = QuantizeConfig::new(OutputFormat::Png);
let result = zenquant::quantize(&pixels, 8, 8, &config).unwrap();

let palette = result.palette();   // &[[u8; 3]]
let indices = result.indices();   // &[u8]

Features

• Perceptual masking: concentrates palette entries where human vision is most sensitive (smooth gradients, skin tones) rather than wasting entries on noisy textures.
• OKLab color space: all clustering happens in a perceptually uniform space, so “nearest color” actually looks nearest.
• Format-aware tuning: palette sorting and dither strength are optimized per output format (GIF, PNG, WebP lossless).
• Shared palettes: build_palette and build_palette_rgba build a single palette from multiple frames, then QuantizeResult::remap maps each frame against it.
• no_std + alloc: always no_std; works in WASM and embedded contexts.

Re-exports

pub use error::QuantizeError;

Modules

error

Structs

Img

Basic struct used for both owned (alias ImgVec) and borrowed (alias ImgRef) image fragments.

QuantizeConfig

Configuration for palette quantization.

QuantizeResult

Result of palette quantization.

RGB

A Red + Green + Blue pixel.

RGBA

A Red + Green + Blue + Alpha pixel.

Enums

OutputFormat

Target output format — controls palette sorting, dither strength, and compression tuning.

Quality

Quality preset — controls k-means iterations, AQ masking, and Viterbi optimization.

Functions

build_palette

Build a shared palette from multiple RGB frames.

build_palette_rgba

Build a shared palette from multiple RGBA frames.

quantize

Quantize an RGB image to an indexed palette.

quantize_rgba

Quantize an RGBA image to an indexed palette.

Type Aliases

ImgRef

Reference to pixels inside another image. Pass this structure by value (i.e. ImgRef, not &ImgRef).

ImgVec

Image owning its pixels.