* Genuary day #2

 * Dithering

 * ---

 * No real dithering, but simple halftone

 */

let img;

let threshold = 127;

​

function preload() {

  img = loadImage('kitten.png');

}

function setup() {

  createCanvas(852, 568);

  imageMode(CENTER);

  strokeWeight(0);

  imageMode(CENTER);

  background(255);

  //noStroke();

  fill(0);

​

  let lineLen = 10;

  threshold = map(mouseY, 0, img.height, 0, 500);

​

  displayByColor("K", 0, 7);

  //displayByColor("C", 1, 5);

  //displayByColor("M", 2, 4);

  //displayByColor("J", 3, 3);

}

​

function displayByColor(col, shifting, maxSize) {

  if (col == "K") fill(0);

  else if (col == "R") fill(255, 0, 0);

  else if (col == "G") fill(0, 255, 0);

  else if (col == "B") fill(0, 0, 255);

  else if (col == "C") fill(0, 255, 255);

  else if (col == "M") fill(255, 0, 255);

  else if (col == "J") fill(255, 255, 0);

  let c = 255;

  for (let i = shifting; i < img.width; i+=6) {

    for (let j = shifting; j < img.height; j+=6) {

      if (col == "K") c = brightness(img.get(i, j));

      else if (col == "R") c = red(img.get(i, j));

      else if (col == "G") c = green(img.get(i, j));

      else if (col == "B") c = blue(img.get(i, j));

      else if (col == "C") c = (blue(img.get(i, j)) + green(img.get(i, j)) ) /2;

      else if (col == "M") c = (blue(img.get(i, j)) + red(img.get(i, j)) ) /2;

      else if (col == "J") c = (red(img.get(i, j)) + green(img.get(i, j)) ) /2;

      let size = map(c, 0, 255, maxSize, 0);

      circle(i-size/2, j-size/2, size);

    }

  }

}

​

​