vivaxy/png

🖼A full-featured PNG decoder and encoder.

png

🖼A full-featured PNG decoder and encoder.

Supports

• Environments: Browsers and Node.js
• Chunks: IHDR, PLTE, IDAT, IEND, tRNS, cHRM, gAMA, iCCP, sBIT, sRGB, tEXt, zTXt, iTXt, bKGD, hIST, pHYs, sPLT, tIME
• Color Types: Greyscale, Truecolour, Indexed-colour (Palette), Greyscale with alpha, Truecolour with alpha
• Bit Depths: 1, 2, 4, 8, 16
• Filters: None, Sub, Up, Average, Paeth

Install

yarn add @vivaxy/png or npm i @vivaxy/png

Usage

import * as png from '@vivaxy/png';

const metadata = png.decode(imageBuffer);
const imageBuffer = png.encode(metadata);

See metadata type definition in metadata.ts.

Articles

• Decoding A PNG Image with JavaScript Step by Step 中文版：一步一步解码 PNG 图片

Prior Art

• PngSuite - the official set of PNG test images
• upng-js
• PNGjs-Image
• fast-png
• pngparse-sync
• pngjs3
• pngjs
• png-js

Project created by create-n.

png's Issues

Add support to enforcing filter.

decode(): ImageData should match input format

First of all, thanks for this fantastic little library! I'm using it for reading 16 bit rgb images and noticed that the decoded data always contains 4 channels (rgba). This makes it very difficult to continue processing the image data in my workflow.

I therefore suggest that the decoded data format matches that specified by the colorType. So for colorType = 1, the format should be [b0, b1, b2...], for colorType = 2 it should be [r0, g0, b0, r1, g1, b1...], etc.

This could also be made a parameter to the decode() function.

Add support to pako options.

• level
• strategy
• chunkSize