(function( $ ){

/**
 * A Point is really used as a 2-dimensional vector, equally useful for 
 * representing a point on a plane, or the height and width of a plane
 * not requiring any other frame of reference.
 * @class
 * @param {Number} [x] The vector component 'x'. Defaults to the origin at 0.
 * @param {Number} [y] The vector component 'y'. Defaults to the origin at 0.
 * @property {Number} [x] The vector component 'x'. 
 * @property {Number} [y] The vector component 'y'.
 */
$.Point = function( x, y ) {
    this.x = typeof ( x ) == "number" ? x : 0;
    this.y = typeof ( y ) == "number" ? y : 0;
};

$.Point.prototype = {

    /**
     * Add another Point to this point and return a new Point.
     * @function
     * @param {OpenSeadragon.Point} point The point to add vector components.
     * @returns {OpenSeadragon.Point} A new point representing the sum of the
     *  vector components
     */
    plus: function( point ) {
        return new $.Point(
            this.x + point.x, 
            this.y + point.y
        );
    },

    /**
     * Add another Point to this point and return a new Point.
     * @function
     * @param {OpenSeadragon.Point} point The point to add vector components.
     * @returns {OpenSeadragon.Point} A new point representing the sum of the
     *  vector components
     */
    minus: function( point ) {
        return new $.Point(
            this.x - point.x, 
            this.y - point.y
        );
    },

    /**
     * Add another Point to this point and return a new Point.
     * @function
     * @param {OpenSeadragon.Point} point The point to add vector components.
     * @returns {OpenSeadragon.Point} A new point representing the sum of the
     *  vector components
     */
    times: function( factor ) {
        return new $.Point(
            this.x * factor, 
            this.y * factor
        );
    },

    /**
     * Add another Point to this point and return a new Point.
     * @function
     * @param {OpenSeadragon.Point} point The point to add vector components.
     * @returns {OpenSeadragon.Point} A new point representing the sum of the
     *  vector components
     */
    divide: function( factor ) {
        return new $.Point(
            this.x / factor, 
            this.y / factor
        );
    },

    /**
     * Add another Point to this point and return a new Point.
     * @function
     * @param {OpenSeadragon.Point} point The point to add vector components.
     * @returns {OpenSeadragon.Point} A new point representing the sum of the
     *  vector components
     */
    negate: function() {
        return new $.Point( -this.x, -this.y );
    },

    /**
     * Add another Point to this point and return a new Point.
     * @function
     * @param {OpenSeadragon.Point} point The point to add vector components.
     * @returns {OpenSeadragon.Point} A new point representing the sum of the
     *  vector components
     */
    distanceTo: function( point ) {
        return Math.sqrt(
            Math.pow( this.x - point.x, 2 ) +
            Math.pow( this.y - point.y, 2 )
        );
    },

    /**
     * Add another Point to this point and return a new Point.
     * @function
     * @param {OpenSeadragon.Point} point The point to add vector components.
     * @returns {OpenSeadragon.Point} A new point representing the sum of the
     *  vector components
     */
    apply: function( func ) {
        return new $.Point( func( this.x ), func( this.y ) );
    },

    /**
     * Add another Point to this point and return a new Point.
     * @function
     * @param {OpenSeadragon.Point} point The point to add vector components.
     * @returns {OpenSeadragon.Point} A new point representing the sum of the
     *  vector components
     */
    equals: function( point ) {
        return ( 
            point instanceof $.Point 
        ) && ( 
            this.x === point.x 
        ) && ( 
            this.y === point.y 
        );
    },

    /**
     * Add another Point to this point and return a new Point.
     * @function
     * @param {OpenSeadragon.Point} point The point to add vector components.
     * @returns {OpenSeadragon.Point} A new point representing the sum of the
     *  vector components
     */
    toString: function() {
        return "(" + this.x + "," + this.y + ")";
    }
};

}( OpenSeadragon ));