Small library to help working with palette based PNGs.
npm install png-palettepng-palette)Small library to help working with palette based PNGs. It provides low-level control over the PLTE (Palette) and tRNS (Transparency) chunks, making it ideal for creating indexed-color images directly.
- Palette Control: Easily set and get RGB colors in the palette.
- Transparency Support: Set alpha values for individual palette indices via the tRNS chunk.
- Efficient Encoding/Decoding: Fast round-trip between raw bytes and a manipulatable image object.
- Minimal Dependencies: Lightweight with only pako for compression and crc-32 for integrity checks.
``bash`
npm install png-paletteor
pnpm add png-palette
`typescript
import { PNGPaletteImage } from "png-palette";
import * as fs from "fs";
// 1. Create a new 10x10 image
const img = new PNGPaletteImage(10, 10);
// 2. Define colors in the palette
img.setPaletteColor(0, 255, 255, 255); // Index 0: White
img.setPaletteColor(1, 255, 0, 0); // Index 1: Red
img.setPaletteColor(2, 0, 0, 255); // Index 2: Blue
// 3. Set transparency (optional)
img.setTransparency(0, 0); // Index 0 is fully transparent
// 4. Draw pixels using palette indices
for (let y = 0; y < 10; y++) {
for (let x = 0; x < 10; x++) {
img.setPixelPaletteIndex(x, y, (x + y) % 2 === 0 ? 1 : 2);
}
}
// 5. Encode to PNG bytes
const pngBytes = img.encodeToPngBytes();
// 6. Save to a file
fs.writeFileSync("output.png", pngBytes);
// 7. Load from existing bytes
const loadedImg = PNGPaletteImage.fromPngBytes(pngBytes);
console.log(Loaded image size: ${loadedImg.width}x${loadedImg.height});`
bash
npm run build
`$3
bash
npm test
``