​

function preload() {

  catImage = loadImage("cat.jpg");

}

​

function setup() {

  createCanvas(catImage.width, catImage.height);

  pixelDensity(1);

​

  // loadPixels();

  catImage.loadPixels();

​

  // Making every other pixel green

  for (let y = 0; y < height; y += 2) {

    for (let x = 0; x < width; x += 2) {

      let index = (x + width * y) * 4;

      catImage.pixels[index + 0] = 0;

      catImage.pixels[index + 1] = 255;

      catImage.pixels[index + 2] = 0;

      catImage.pixels[index + 3] = 255;

    }

  }

​

  // Erasing line that is 10 pixels tall across middle

  for (let y = height/2 - 5; y < height/2 + 5; y++) {

    for (let x = 0; x < width; x++) {

      let index = (x + width * y) * 4;

      catImage.pixels[index + 0] = 0;

      catImage.pixels[index + 1] = 0;

      catImage.pixels[index + 2] = 0;

      catImage.pixels[index + 3] = 0;

    }

  }

  // Colored line blue that is 10 pixels wide down middle

  for (let y = 0; y < height; y++) {

    for (let x = width/2 - 5; x < width/2 + 5; x++) {

      let index = (x + width * y) * 4;

      catImage.pixels[index + 0] = 0;

      catImage.pixels[index + 1] = 0;

      catImage.pixels[index + 2] = 255;

      catImage.pixels[index + 3] = 255;

    }

  }

​

  catImage.updatePixels();

​

​

  image(catImage, 0, 0);

}

​

function draw() {

​

}