png-img.js

// https://github.com/gemini-testing/png-img
'use strict;'
var PngImg = require('png-img');

function save(pixel_data, width, height, file_path) {
  // init with 1x1 PNG buffer.
  var tmp = new PngImg(new Buffer([137, 80, 78, 71, 13, 10, 26, 10, 0, 0, 0, 13, 73, 72, 68, 82, 0, 0, 0, 1, 0, 0, 0, 1, 8, 2, 0, 0, 0, 144, 119, 83, 222, 0, 0, 0, 1, 115, 82, 71, 66, 0, 174, 206, 28, 233, 0, 0, 0, 12, 73, 68, 65, 84, 8, 29, 99, 96, 96, 96, 0, 0, 0, 4, 0, 1, 100, 50, 83, 254, 0, 0, 0, 0, 73, 69, 78, 68, 174, 66, 96, 130]));
  tmp.setSize(width, height);
  var idx = 0;
  var color = {};
  for (var y = 0; y < height; y++) {
    for (var x = 0; x < width; x++) {
      color.r = pixel_data[idx++];
      color.g = pixel_data[idx++];
      color.b = pixel_data[idx++];
      color.a = pixel_data[idx++];
      tmp.set(x, y, color);
    }
  }
  tmp.save(file_path, null);
}

function load(file_path) {
  var data = fs.readFileSync(file_path);
  var tmp = new PngImg(data);
  var size = tmp.size();
  var width = size.width;
  var height = size.height;
  var pixel_data = new Buffer(width * height * 4);
  var idx = 0;
  for (var y = 0; y < height; y++) {
    for (var x = 0; x < width; x++) {
      var color = tmp.get(x, y);
      pixel_data[idx++] = color.r;
      pixel_data[idx++] = color.g;
      pixel_data[idx++] = color.b;
      pixel_data[idx++] = color.a;
    }
  }
  return {
    width: width,
    height: height,
    pixel_data: pixel_data
  };
}

png-light.js

// https://github.com/baslr/png-light
'use strict;'
var PNG = require('png-light'),
    fs = require('fs');

function save(pixel_data, width, height, file_path) {
  var tmp = new PNG({width: width, height: height});
  pixel_data.copy(tmp.data);
  var buffer = tmp.pack();
  fs.writeFileSync(file_path, buffer);
}

function load(file_path) {
  var buffer = fs.readFileSync(file_path);
  var tmp = new PNG({buffer: buffer});
  var pixel_data = new Buffer(tmp.width * tmp.height * 4);
  tmp.data.copy(pixel_data);
  return {
    width: tmp.width,
    height: tmp.height,
    pixel_data: pixel_data
  };
}

pngjs.js

// https://github.com/lukeapage/pngjs
'use strict;'
var png = require('pngjs'),
    fs = require('fs');

function save(pixel_data, width, height, file_path) {
  var tmp = new png.PNG({width: width, height: height});
  pixel_data.copy(tmp.data);
  var buffer = png.PNG.sync.write(tmp);
  fs.writeFileSync(file_path, buffer);
}

function load(file_path) {
  var data = fs.readFileSync(file_path);
  var tmp = png.PNG.sync.read(data);
  var pixel_data = new Buffer(tmp.width * tmp.height * 4);
  tmp.data.copy(pixel_data);
  return {
    width: tmp.width,
    height: tmp.height,
    pixel_data: pixel_data
  };
}

pnglib.js

// https://github.com/GeorgeChan/pnglib
'use strict;'
var pnglib = require('pnglib'),
    fs = require('fs');

function save(pixel_data, width, height, file_path) {
  var tmp = new pnglib(width, height, 24);
  var idx = 0;
  for (var y = 0; y < height; y++) {
    for (var x = 0; x < width; x++) {
      var r = pixel_data[idx++];
      var g = pixel_data[idx++];
      var b = pixel_data[idx++];
      var a = pixel_data[idx++];
      var index = tmp.index(x, y);
      tmp.buffer[index] = tmp.color(r, g, b, a);
    }
  }
  var b64 = tmp.getBase64();
  var buf = new Buffer(b64, 'base64');
  fs.writeFileSync(file_path, buf);
}