tiny-png

A minimal, dependency-free TypeScript PNG encoder for indexed color images.

Usage

import { indexedPng } from '@levischuck/tiny-png';

// Create an indexed PNG from pixel data
// Input is a Uint8Array where each byte is a palette index
const width = 100;
const height = 100;
const pixels = new Uint8Array(width * height);
// ... fill pixels with palette indices (0, 1, 2, etc.)

// Define color palette: [R, G, B] tuples
const colors: [number, number, number][] = [
  [255, 255, 255], // Index 0: white
  [0, 0, 0],       // Index 1: black
  [255, 0, 0],     // Index 2: red
];

const pngBytes = await indexedPng(pixels, width, height, colors);

// Write to file
await Bun.write('output.png', pngBytes);

API

indexedPng(input: Uint8Array, width: number, height: number, colors: [number, number, number][]): Promise<Uint8Array>

Generates an indexed-color PNG image.

Parameters:

• input - Pixel data as a Uint8Array where each byte is a palette index
• width - Image width in pixels
• height - Image height in pixels
• colors - Color palette as an array of [R, G, B] tuples (0-255)

Returns: Promise resolving to PNG file bytes as a Uint8Array

Throws: Error if the color palette doesn't have enough colors for the highest index in the input data.

License

MIT Licensed.