HTML5 Canvas set z-index

Question

Is it possible to set the z-index of a drawn object in HTML5 canvas?

I am trying to get it so one object can be infront of a the \"player\" and another object is beh

Answer 1

Yes..kind of yes. You can use compositing to "draw behind" existing pixels.

ctx.globalCompositeOperation='destination-over';

Here's an example and a Demo:

var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");

var cx=100;

drawCircle()
cx+=20;

ctx.globalCompositeOperation='destination-over';

$("#test").click(function(){
  drawCircle();
  cx+=20;
});

function drawCircle(){
  ctx.beginPath();
  ctx.arc(cx,150,20,0,Math.PI*2);
  ctx.closePath();
  ctx.fillStyle=randomColor();
  ctx.fill();
}

function randomColor(){ 
  return('#'+Math.floor(Math.random()*16777215).toString(16));
}

body{ background-color: ivory; }
canvas{border:1px solid red;}

Draw new circle behind.