Source: math-extras/rectangleExtras.ts

import { Rectangle } from '../maths/shapes/Rectangle';

export const rectangleExtraMixins: Partial<Rectangle> = {
    /**
     * Determines whether the `other` Rectangle is contained within `this` Rectangle object.
     * Rectangles that occupy the same space are considered to be containing each other.
     * Rectangles without area (width or height equal to zero) can't contain anything,
     * not even other arealess rectangles.
     *
     * _Note: Only available with **pixi.js/math-extras**._
     * @method containsRect
     * @memberof maths.Rectangle#
     * @param {Rectangle} other - The Rectangle to fit inside `this`.
     * @returns {boolean} A value of `true` if `this` Rectangle contains `other`; otherwise `false`.
     */
    containsRect(other: Rectangle): boolean
    {
        if (other.width <= 0 || other.height <= 0)
        {
            return other.x > this.x && other.y > this.y && other.right < this.right && other.bottom < this.bottom;
        }

        return other.x >= this.x && other.y >= this.y && other.right <= this.right && other.bottom <= this.bottom;
    },
    /**
     * Accepts `other` Rectangle and returns true if the given Rectangle is equal to `this` Rectangle.
     *
     * _Note: Only available with **pixi.js/math-extras**._
     * @method equals
     * @memberof maths.Rectangle#
     * @param {Rectangle} other - The Rectangle to compare with `this`
     * @returns {boolean} Returns true if all `x`, `y`, `width`, and `height` are equal.
     */
    equals(other: Rectangle): boolean
    {
        if (other === this)
        {
            return true;
        }

        return (
            other
            && this.x === other.x
            && this.y === other.y
            && this.width === other.width
            && this.height === other.height
        );
    },

    /**
     * If the area of the intersection between the Rectangles `other` and `this` is not zero,
     * returns the area of intersection as a Rectangle object. Otherwise, return an empty Rectangle
     * with its properties set to zero.
     * Rectangles without area (width or height equal to zero) can't intersect or be intersected
     * and will always return an empty rectangle with its properties set to zero.
     *
     * _Note: Only available with **pixi.js/math-extras**._
     * @method intersection
     * @memberof maths.Rectangle#
     * @param {Rectangle} other - The Rectangle to intersect with `this`.
     * @param {Rectangle} [outRect] - A Rectangle object in which to store the value,
     * optional (otherwise will create a new Rectangle).
     * @returns {Rectangle} The intersection of `this` and `other`.
     */
    intersection<T extends Rectangle>(other: Rectangle, outRect?: T): T
    {
        if (!outRect)
        {
            outRect = new Rectangle() as T;
        }

        const x0 = this.x < other.x ? other.x : this.x;
        const x1 = this.right > other.right ? other.right : this.right;

        if (x1 <= x0)
        {
            outRect.x = outRect.y = outRect.width = outRect.height = 0;

            return outRect;
        }

        const y0 = this.y < other.y ? other.y : this.y;
        const y1 = this.bottom > other.bottom ? other.bottom : this.bottom;

        if (y1 <= y0)
        {
            outRect.x = outRect.y = outRect.width = outRect.height = 0;

            return outRect;
        }

        outRect.x = x0;
        outRect.y = y0;
        outRect.width = x1 - x0;
        outRect.height = y1 - y0;

        return outRect;
    },

    /**
     * Adds `this` and `other` Rectangles together to create a new Rectangle object filling
     * the horizontal and vertical space between the two rectangles.
     *
     * _Note: Only available with **pixi.js/math-extras**._
     * @method union
     * @memberof maths.Rectangle#
     * @param {Rectangle} other - The Rectangle to unite with `this`.
     * @param {Rectangle} [outRect] - A Rectangle object in which to store the value,
     * optional (otherwise will create a new Rectangle).
     * @returns {Rectangle} The union of `this` and `other`.
     */
    union<T extends Rectangle>(other: Rectangle, outRect?: T): T
    {
        if (!outRect)
        {
            outRect = new Rectangle() as T;
        }

        const x1 = Math.min(this.x, other.x);
        const x2 = Math.max(this.x + this.width, other.x + other.width);
        const y1 = Math.min(this.y, other.y);
        const y2 = Math.max(this.y + this.height, other.y + other.height);

        outRect.x = x1;
        outRect.y = y1;
        outRect.width = x2 - x1;
        outRect.height = y2 - y1;

        return outRect;
    },
};