PixiJS

Source: core/math/ObservablePoint.js

core/math/ObservablePoint.js

  1. /**
  2.  * The Point object represents a location in a two-dimensional coordinate system, where x represents
  3.  * the horizontal axis and y represents the vertical axis.
  4.  * An observable point is a point that triggers a callback when the point's position is changed.
  5.  *
  6.  * @class
  7.  * @memberof PIXI
  8.  */
  9. export default class ObservablePoint
  10. {
  11.     /**
  12.      * @param {Function} cb - callback when changed
  13.      * @param {object} scope - owner of callback
  14.      * @param {number} [x=0] - position of the point on the x axis
  15.      * @param {number} [y=0] - position of the point on the y axis
  16.      */
  17.     constructor(cb, scope, x = 0, y = 0)
  18.     {
  19.         this._x = x;
  20.         this._y = y;
  22.         this.cb = cb;
  23.         this.scope = scope;
  24.     }
  26.     /**
  27.      * Creates a clone of this point.
  28.      * The callback and scope params can be overidden otherwise they will default
  29.      * to the clone object's values.
  30.      *
  31.      * @override
  32.      * @param {Function} [cb=null] - callback when changed
  33.      * @param {object} [scope=null] - owner of callback
  34.      * @return {PIXI.ObservablePoint} a copy of the point
  35.      */
  36.     clone(cb = null, scope = null)
  37.     {
  38.         const _cb = cb || this.cb;
  39.         const _scope = scope || this.scope;
  41.         return new ObservablePoint(_cb, _scope, this._x, this._y);
  42.     }
  44.     /**
  45.      * Sets the point to a new x and y position.
  46.      * If y is omitted, both x and y will be set to x.
  47.      *
  48.      * @param {number} [x=0] - position of the point on the x axis
  49.      * @param {number} [y=0] - position of the point on the y axis
  50.      */
  51.     set(x, y)
  52.     {
  53.         const _x = x || 0;
  54.         const _y = y || ((y !== 0) ? _x : 0);
  56.         if (this._x !== _x || this._y !== _y)
  57.         {
  58.             this._x = _x;
  59.             this._y = _y;
  60.             this.cb.call(this.scope);
  61.         }
  62.     }
  64.     /**
  65.      * Copies the data from another point
  66.      *
  67.      * @param {PIXI.Point|PIXI.ObservablePoint} point - point to copy from
  68.      */
  69.     copy(point)
  70.     {
  71.         if (this._x !== point.x || this._y !== point.y)
  72.         {
  73.             this._x = point.x;
  74.             this._y = point.y;
  75.             this.cb.call(this.scope);
  76.         }
  77.     }
  79.     /**
  80.      * Returns true if the given point is equal to this point
  81.      *
  82.      * @param {PIXI.Point|PIXI.ObservablePoint} p - The point to check
  83.      * @returns {boolean} Whether the given point equal to this point
  84.      */
  85.     equals(p)
  86.     {
  87.         return (p.x === this._x) && (p.y === this._y);
  88.     }
  90.     /**
  91.      * The position of the displayObject on the x axis relative to the local coordinates of the parent.
  92.      *
  93.      * @member {number}
  94.      */
  95.     get x()
  96.     {
  97.         return this._x;
  98.     }
  100.     set x(value) // eslint-disable-line require-jsdoc
  101.     {
  102.         if (this._x !== value)
  103.         {
  104.             this._x = value;
  105.             this.cb.call(this.scope);
  106.         }
  107.     }
  109.     /**
  110.      * The position of the displayObject on the x axis relative to the local coordinates of the parent.
  111.      *
  112.      * @member {number}
  113.      */
  114.     get y()
  115.     {
  116.         return this._y;
  117.     }
  119.     set y(value) // eslint-disable-line require-jsdoc
  120.     {
  121.         if (this._y !== value)
  122.         {
  123.             this._y = value;
  124.             this.cb.call(this.scope);
  125.         }
  126.     }
  127. }