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pixi.js / lib / core / math / shapes / Polygon.js
@Matt Karl Matt Karl on 22 Feb 2017 3 KB 4.4.0
'use strict';

exports.__esModule = true;

var _Point = require('../Point');

var _Point2 = _interopRequireDefault(_Point);

var _const = require('../../const');

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

/**
 * @class
 * @memberof PIXI
 */
var Polygon = function () {
    /**
     * @param {PIXI.Point[]|number[]} points - This can be an array of Points
     *  that form the polygon, a flat array of numbers that will be interpreted as [x,y, x,y, ...], or
     *  the arguments passed can be all the points of the polygon e.g.
     *  `new PIXI.Polygon(new PIXI.Point(), new PIXI.Point(), ...)`, or the arguments passed can be flat
     *  x,y values e.g. `new Polygon(x,y, x,y, x,y, ...)` where `x` and `y` are Numbers.
     */
    function Polygon() {
        for (var _len = arguments.length, points = Array(_len), _key = 0; _key < _len; _key++) {
            points[_key] = arguments[_key];
        }

        _classCallCheck(this, Polygon);

        if (Array.isArray(points[0])) {
            points = points[0];
        }

        // if this is an array of points, convert it to a flat array of numbers
        if (points[0] instanceof _Point2.default) {
            var p = [];

            for (var i = 0, il = points.length; i < il; i++) {
                p.push(points[i].x, points[i].y);
            }

            points = p;
        }

        this.closed = true;

        /**
         * An array of the points of this polygon
         *
         * @member {number[]}
         */
        this.points = points;

        /**
         * The type of the object, mainly used to avoid `instanceof` checks
         *
         * @member {number}
         * @readOnly
         * @default PIXI.SHAPES.POLY
         * @see PIXI.SHAPES
         */
        this.type = _const.SHAPES.POLY;
    }

    /**
     * Creates a clone of this polygon
     *
     * @return {PIXI.Polygon} a copy of the polygon
     */


    Polygon.prototype.clone = function clone() {
        return new Polygon(this.points.slice());
    };

    /**
     * Closes the polygon, adding points if necessary.
     *
     */


    Polygon.prototype.close = function close() {
        var points = this.points;

        // close the poly if the value is true!
        if (points[0] !== points[points.length - 2] || points[1] !== points[points.length - 1]) {
            points.push(points[0], points[1]);
        }
    };

    /**
     * Checks whether the x and y coordinates passed to this function are contained within this polygon
     *
     * @param {number} x - The X coordinate of the point to test
     * @param {number} y - The Y coordinate of the point to test
     * @return {boolean} Whether the x/y coordinates are within this polygon
     */


    Polygon.prototype.contains = function contains(x, y) {
        var inside = false;

        // use some raycasting to test hits
        // https://github.com/substack/point-in-polygon/blob/master/index.js
        var length = this.points.length / 2;

        for (var i = 0, j = length - 1; i < length; j = i++) {
            var xi = this.points[i * 2];
            var yi = this.points[i * 2 + 1];
            var xj = this.points[j * 2];
            var yj = this.points[j * 2 + 1];
            var intersect = yi > y !== yj > y && x < (xj - xi) * ((y - yi) / (yj - yi)) + xi;

            if (intersect) {
                inside = !inside;
            }
        }

        return inside;
    };

    return Polygon;
}();

exports.default = Polygon;
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