​

let img;

let bytearray = [];

function preload() {

  img = loadImage('full-width-test.bmp')

}

function setup() {

  createCanvas(img.width, img.height);

  image(img,0,0)

  print(img.width)

  print(img.height)

  img.loadPixels()

  let paper = img.height*6

  bytearray = [27,87,0,0,0,0,0,2,paper%256, floor(paper/256)];

  for(let y=0;y<img.height;y+=8){

    bytearray = bytearray.concat([ 27, 42, 0, img.width%256, floor(img.width/256) ])

    for(let x = 0;x<img.width;x++){

      let num=0;

      for(let i=0;i<8;i++){

       if(img.pixels[(y+i) *4*img.width + x*4] < 128){

         num += 2**(7-i);

       }

      }

      bytearray.push(num)

    }

    bytearray = bytearray.concat( [27,74,48])

  }

  print(bytearray)

  let file = new Uint8Array(bytearray.length);

  file.set(bytearray);

  // save with a blob object

  let blob = new Blob([file], { type: 'application/octet-stream' });

  let link = createA('', filename + '.rct');

  let url = URL.createObjectURL(blob);

  link.attribute('href', url);

  link.attribute('download', filename + '.rct');

  link.elt.click();

  URL.revokeObjectURL(url);

  link.remove()

}

​