Example 1: Basic Circle

refresh(dc, width, height) // Sample code by Jim Bumgardner
{
  dc.clearRect(0,0,width,height);
  
  dc.fillStyle='#000';
  dc.beginPath();
  var cx = width/2;
  var cy = height/2;
  var rad = width*.45;
  
  dc.arc(cx, cy, rad, 0,2*Math.PI, false);
  dc.fill();
  
}