let maxVal = 2.5;

​

let minSlider;

let maxSlider;

​

function setup() {

  createCanvas(200, 200);

  pixelDensity(1);

  minSlider = createSlider(-2.5, 0, -2.5, 0.01);

  maxSlider = createSlider(0, 2.5, 2.5, 0.01);

​

}

​

function draw() {

  let maxiterations = 100;

  loadPixels();

  for (let x=0; x<width; x++){

    for (let y=0; y<height; y++){

      let a = map(x, 0, width, minSlider.value(), maxSlider.value());

      let b = map(y, 0, height, minSlider.value(), maxSlider.value());

      let ca = a;

      let cb = b;

      let n = 0;

      while (n < maxiterations){

        let aa = a*a - b*b;

        let bb = 2 * a * b;

        a = aa + ca;

        b = bb + cb;

        if (a + b > 16) {

          break;

        }

        n++;

      }

      let bright = map(n, 0, maxiterations, 0, 1);

      bright = map(sqrt(bright), 0, 1, 0, 255);

      if (n == maxiterations) {

        bright = 0;

      } 

      let pix = (x + y * width) * 4;

      pixels[pix + 0] = bright;

      pixels[pix + 1] = bright;

      pixels[pix + 2] = bright;

      pixels[pix + 3] = 255;

    }

  }

  updatePixels();

}

​