Readable Radial Gradient

var size:Number = 400;
var halfSize:Number = size / 2;
var canvas:BitmapData = new BitmapData(size, size,false, 0x000000);
addChild(new Bitmap(canvas, PixelSnapping.AUTO, true));

var rings:Number = 40;
var color:uint, theta:Number, dx:Number, dy:Number;

for (var i:int = 0; i<canvas.width; i++){
	for (var j:int = 0; j<canvas.height; j++){
		// distance from center of canvas to current x, y coord 
		dx = i - halfSize;
		dy = j - halfSize;
		theta = Math.sqrt((dx * dx)+(dy * dy)) * rings;
		color = (100 + 100  * Math.sin(theta * Math.PI/180)) << 16;
		canvas.setPixel(i,  j, color);
	}
}

/*
WARNING: This code was written for fun. Use at your own risk.
*/

This is the previous post written in a readable way. Draws a radial gradient using pythagorean theorem and sine.