Onclick Function Button Change Canvas

I have the following code creating an animated series of lines in canvas. I would like to change the context being drawn in the canvas depending on certain DOM elements being click

Solution 1:

You just want a click-handler on #click to change your wave colors?

$('#click').on('click',function(){
  m = ceil(w/(10*u)) + Math.random()*10*8;
});

Example code and a Demo:

var c = document.querySelector('.c'), 
w, h,
ctx = c.getContext('2d'), 

x0, y0, x, y, 
t = 0, t_step = 1/200, 
u = 5, m, 
tmp, 


ceil = Math.ceil, 
exp = Math.exp, pow = Math.pow, sqrt = Math.sqrt, 
PI = Math.PI, sin = Math.sin, cos = Math.cos;

var rand = function(max, min) {
  var b = (max === 0 || max) ? max : 1, a = min || 0;

  return a + (b - a)*Math.random();
};

var trimUnit = function(input_str, unit) {
  returnparseInt(input_str.split(unit)[0], 10);
};

var initCanvas = function() {
  var s = getComputedStyle(c);

  w = c.width = trimUnit(s.width, 'px');
  h = c.height = trimUnit(s.height, 'px');

  m = ceil(w/(10*u)) + 25;
};

var wave = function () {
  ctx.clearRect(0, 0, w, h);
  ctx.lineWidth = 2;

  for(var i = 0; i < m; i++) {
    x0 = -20;
    y0 = i*2*u;

    ctx.beginPath();
    ctx.moveTo(x0, y0);

    for(x = 0; x < w; x++) {
      y =  u*sin(x/6/(16*i/m + 1) - w*(i/m + 1)*t/120) + i*2*u;

      ctx.lineTo(x, y);

      x0 = x;
      y0 = y;
    }
    ctx.strokeStyle = 'hsl(' + i*360/m + ', 100%, 70%)';
    ctx.stroke();
  }

 t += t_step;

  requestAnimationFrame(wave);
};

addEventListener('resize', initCanvas, false);

$('#click').on('click',function(){
  m = ceil(w/(10*u)) + Math.random()*10*8;
});

initCanvas();
wave();

<scriptsrc="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script><h4>Click on sun to <br>change wave colors.</h4><canvasclass='c'>waves</canvas><divstyle="width:100%; height:100%; position:absolute; top:0; left:0;"><center><imgid="click"style="margin:0 auto; position:relative; top:35%; width:100px; height:auto;"src="https://dl.dropboxusercontent.com/u/139992952/multple/sunny.png"alt="" ></center>