File:Ellipse.js

/**
 * @module Native Display
 * @namespace springroll.native
 * @requires Core
 */
(function()
{
	/**
	 * The Ellipse object can be used to specify a hit area for displayobjects
	 *
	 * @class Ellipse
	 * @constructor
	 * @param x {Number} The X coord of the upper-left corner of the framing rectangle of this ellipse
	 * @param y {Number} The Y coord of the upper-left corner of the framing rectangle of this ellipse
	 * @param width {Number} The overall width of this ellipse
	 * @param height {Number} The overall height of this ellipse
	 */
	var Ellipse = function(x, y, width, height)
	{
		/**
		 * @property x
		 * @type Number
		 * @default 0
		 */
		this.x = x || 0;

		/**
		 * @property y
		 * @type Number
		 * @default 0
		 */
		this.y = y || 0;

		/**
		 * @property width
		 * @type Number
		 * @default 0
		 */
		this.width = width || 0;

		/**
		 * @property height
		 * @type Number
		 * @default 0
		 */
		this.height = height || 0;
	};

	var p = extend(Ellipse);

	/**
	 * Creates a clone of this Ellipse instance
	 *
	 * @method clone
	 * @return {Ellipse} a copy of the ellipse
	 */
	p.clone = function()
	{
		return new Ellipse(this.x, this.y, this.width, this.height);
	};

	/**
	 * Checks if the x, and y coords passed to this function are contained within this ellipse
	 *
	 * @method contains
	 * @param x {Number} The X coord of the point to test
	 * @param y {Number} The Y coord of the point to test
	 * @return {Boolean} if the x/y coords are within this ellipse
	 */
	p.contains = function(x, y)
	{
		if (this.width <= 0 || this.height <= 0)
			return false;

		//normalize the coords to an ellipse with center 0,0
		//and a radius of 0.5
		var normx = ((x - this.x) / this.width) - 0.5,
			normy = ((y - this.y) / this.height) - 0.5;

		normx *= normx;
		normy *= normy;

		return (normx + normy < 0.25);
	};

	Ellipse.getBounds = function()
	{
		return new Rectangle(this.x, this.y, this.width, this.height);
	};

	// constructor
	p.constructor = Ellipse;

	// Assign to namespace
	namespace('springroll.native').Ellipse = Ellipse;

}());