/**

 *  autor: foqc

 *  github: foqc

 */

// noprotect

var canvas = document.getElementById('myCanvas')

var ctx = canvas.getContext('2d')

ctx.canvas.width = window.innerWidth;

ctx.canvas.height = window.innerHeight;

​

const MAX_ITERATION = 80

const WIDTH = window.innerWidth

const HEIGHT = window.innerHeight

​

const REAL_SET = { start: -2, end: 1 }

const IMAGINARY_SET = { start: -1, end: 1 }

​

const colors = new Array(16).fill(0).map((_, i) => i === 0 ? '#000' : `#${((1 << 24) * Math.random() | 0).toString(16)}`)

​

function mandelbrot(c) {

    let z = { x: 0, y: 0 }, n = 0, p, d;

    do {

        p = {

            x: Math.pow(z.x, 2) - Math.pow(z.y, 2),

            y: 2 * z.x * z.y

        }

        z = {

            x: p.x + c.x,

            y: p.y + c.y

        }

        d = Math.sqrt(Math.pow(z.x, 2) + Math.pow(z.y, 2))

        n += 1

    } while (d <= 2 && n < MAX_ITERATION)

    return [n, d <= 2]

}

​

function draw() {

    for (let i = 0; i < WIDTH; i++) {

        for (let j = 0; j < HEIGHT; j++) {

            complex = {

                x: REAL_SET.start + (i / WIDTH) * (REAL_SET.end - REAL_SET.start),

                y: IMAGINARY_SET.start + (j / HEIGHT) * (IMAGINARY_SET.end - IMAGINARY_SET.start)

            }

​

            const [m, isMandelbrotSet] = mandelbrot(complex)

            ctx.fillStyle = colors[isMandelbrotSet ? 0 : (m % colors.length - 1) + 1]

            ctx.fillRect(i, j, 1, 1)

        }

    }

}

​

draw()

​