node-png-metadata

PNG metadata read and write

install

$ npm install png-metadata

require

var png = require('png-metadata');

how to use

// load from file
var s = png.readFileSync('aaa.png');
// split
var list = png.splitChunk(s);
// append
var iend = list.pop(); // remove IEND
var newchunk = png.createChunk("aaAa","test data");
list.push(newchunk);
list.push(iend);
// join
var newpng = png.joinChunk(list);
// save to file
fs.writeFileSync(outfile, newpng, 'binary');