/**
* The Point object represents a location in a two-dimensional coordinate system, where x represents the horizontal axis and y represents the vertical axis.
* An observable point is a point that triggers a callback when the point's position is changed.
*
* @class
* @memberof Tiny
*/
export default class ObservablePoint {
/**
* @param {function} cb - callback when changed
* @param {object} scope - owner of callback
* @param {number} [x=0] - position of the point on the x axis
* @param {number} [y=0] - position of the point on the y axis
*/
constructor(cb, scope, x = 0, y = 0) {
this._x = x;
this._y = y;
this.cb = cb;
this.scope = scope;
}
/**
* Creates a clone of this point.
* The callback and scope params can be overidden otherwise they will default to the clone object's values.
*
* @override
* @version 1.2.0
* @param {function} [cb=null] - callback when changed
* @param {object} [scope=null] - owner of callback
* @return {Tiny.ObservablePoint} a copy of the point
*/
clone(cb = null, scope = null) {
const _cb = cb || this.cb;
const _scope = scope || this.scope;
return new ObservablePoint(_cb, _scope, this._x, this._y);
}
/**
* Sets the point to a new x and y position.
* If y is omitted, both x and y will be set to x.
*
* @param {number} [x=0] - position of the point on the x axis
* @param {number} [y=0] - position of the point on the y axis
*/
set(x, y) {
const _x = x || 0;
const _y = y || ((y !== 0) ? _x : 0);
if (this._x !== _x || this._y !== _y) {
this._x = _x;
this._y = _y;
this.cb.call(this.scope);
}
}
/**
* Copies the data from another point
*
* @param {Tiny.Point|Tiny.ObservablePoint} point - point to copy from
*/
copy(point) {
if (this._x !== point.x || this._y !== point.y) {
this._x = point.x;
this._y = point.y;
this.cb.call(this.scope);
}
}
/**
* Returns true if the given point is equal to this point
*
* @version 1.2.0
* @param {Tiny.Point|Tiny.ObservablePoint} p - The point to check
* @return {boolean} Whether the given point equal to this point
*/
equals(p) {
return (p.x === this._x) && (p.y === this._y);
}
/**
* The position of the displayObject on the x axis relative to the local coordinates of the parent.
*
* @member {number}
*/
get x() {
return this._x;
}
set x(value) {
if (this._x !== value) {
this._x = value;
this.cb.call(this.scope);
}
}
/**
* The position of the displayObject on the x axis relative to the local coordinates of the parent.
*
* @member {number}
*/
get y() {
return this._y;
}
set y(value) {
if (this._y !== value) {
this._y = value;
this.cb.call(this.scope);
}
}
}