dss/static/js/libs/point.js

/**
 * Adobe Docs: http://bit.ly/b2RieL
 *
 * // TODO: Reconstruct Point so we can inherit from it. Use .addProperties
 * for getters and setters
 *
 * @constructor
 * @param {number} x The x coordinate.
 * @param {number} y The y coordinate.
 */
Point = Point = function (x, y) {

    this.x = x || 0;
    this.y = y || 0;

};

/**
 * @this Point
 * @return The length from {0,0}.
 */
Point.prototype.getLength = function () {
    return Math.sqrt((this.x * this.x) + (this.y * this.y));
};

Point.prototype.add = function (v) {

    return new Point(this.x + v.x, this.y + v.y);

};

Point.prototype.clone = function () {

    return new Point(this.x, this.y);

};

Point.prototype.distance = function (pt1, pt2) {

    var a = Math.abs(pt2.x - pt1.x),
        b = Math.abs(pt2.y - pt1.y);

    return Math.sqrt((a * a) + b * b);

};

Point.prototype.equals = function (toCompare) {

    return (this.x === toCompare.x) && (this.y === toCompare.y);

};

/**
 * interpolate(pt1:Point, pt2:Point, f:Number):Point
 * [static] Determines a point between two specified points.
 *
 * @param {Point} pt1 Point to compare.
 * @param {Point} pt2 Point to compare.
 * @param {number} f position between points, from 0 to 1.
 *
 * @return {Point} A new point.
 */
Point.prototype.interpolate = function (pt1, pt2, f) {

    // http://en.wikipedia.org/wiki/Linear_interpolation

    var a = pt1.x + ((pt2.x - pt1.x) * f),
        b = pt1.y + (a - pt1.x) * ((pt2.y - pt1.y) / (pt2.x - pt1.x));

    return new Point(a, b);

};

/**
 * normalize(thickness:Number):void
 * Scales line segment, between (0,0) and current point, to a set length.
 */
Point.prototype.normalize = function (thickness) {

    var n = (this.getLength() - thickness) / this.getLength();

    //console.log('Thickness = ', thickness, ', length: ', this.getLength(), ', n: ', n);

    return new Point(this.x - (this.x * n), this.y - (this.y * n));

};

Point.prototype.offset = function (dx, dy) {

    this.x = this.x + dx;
    this.y = this.y + dy;

};

/**
 * Wikipedia article on converting between polar and cartesian:
 * http://bit.ly/cuZNzu
 *
 * polar(len:Number, angle:Number):Point
 * [static] Converts a pair of polar coordinates to a
 * Cartesian point coordinate.
 *
 * @param {number} len — The length coordinate of the polar pair.
 * @param {number} angle — The angle, in radians, of the polar pair.
 *
 * @return {Point} a new point.
 */
Point.prototype.polar = function (len, angle) {

    // Convert cartesian to polar
    /*
     var a = this.length,
     theta = Math.atan2(y, x);

     return new Point(a, theta);
     */

    var x = len * Math.cos(angle),
        y = len * Math.sin(angle);

    return new Point(x, y);

};

Point.prototype.subtract = function (v) {

    return new Point(this.x - v.x, this.y - v.y);

};

Point.prototype.toString = function () {

    return '{x:' + this.x +
        ', y:' + this.y +
        ', length:' + this.getLength() + '}';

};