showFromPNG.js

var LED = require("./cpp/build/Release/DrOcto");

var sending = false;

var fs = require('fs');
var PNG = require('pngjs').PNG;

console.time("load");
fs.createReadStream('images/active.png')
  .pipe(new PNG({
    filterType: 4
  }))
  .on('parsed', function(data) {
    console.timeEnd("load");
    console.time("process");

    var arr = Array(2400).fill(0x000000);

    for (var y = 0; y < this.height; y++) {
      for (var x = 0; x < this.width; x++) {
	var idx = (this.width * y + x) << 2;
	var pixel = this.data[idx] << 16 | this.data[idx+1] << 8 | this.data[idx+2];
	// console.log("pixel pos x:i ", x, " y: ", y, " [",this.data[idx].toString(16), this.data[idx+1].toString(16), this.data[idx+2].toString(16), "]", "->", pixel);
	// if(x == 0 && y < 6) pixel=0x000000;
	// pixel=0x000000;
	arr[getCoord(x,y)] = pixel;

      }
    }

    LED.calculate_results_async(60, 40, arr, function(err, result) {
      sending = false;
    });

    console.timeEnd("process");

    //this.pack().pipe(fs.createWriteStream('out.png'));
  });

sending = true;
function getCoord(x,y){
  return y * 60 + x;
}