esengine/source/src/Math/Rectangle.ts

class Rectangle extends egret.Rectangle {
    /**
     * 获取矩形的最大点，即右下角
     */
    public get max() {
        return new Vector2(this.right, this.bottom);
    }

    /** 中心点坐标 */
    public get center() {
        return new Vector2(this.x + (this.width / 2), this.y + (this.height / 2));
    }

    /** 左上角的坐标 */
    public get location() {
        return new Vector2(this.x, this.y);
    }
    /** 左上角的坐标 */
    public set location(value: Vector2) {
        this.x = value.x;
        this.y = value.y;
    }

    public get size() {
        return new Vector2(this.width, this.height);
    }

    public set size(value: Vector2) {
        this.width = value.x;
        this.height = value.y;
    }

    /**
     * 是否与另一个矩形相交
     * @param value 
     */
    public intersects(value: egret.Rectangle) {
        return value.left < this.right &&
            this.left < value.right &&
            value.top < this.bottom &&
            this.top < value.bottom;
    }

    /**
     * 获取所提供的矩形是否在此矩形的边界内
     * @param value 
     */
    public containsRect(value: Rectangle) {
        return ((((this.x <= value.x) && (value.x < (this.x + this.width))) &&
            (this.y <= value.y)) &&
            (value.y < (this.y + this.height)));
    }

    public getHalfSize() {
        return new Vector2(this.width * 0.5, this.height * 0.5);
    }

    /**
     * 创建一个矩形的最小/最大点(左上角，右下角的点)
     * @param minX 
     * @param minY 
     * @param maxX 
     * @param maxY 
     */
    public static fromMinMax(minX: number, minY: number, maxX: number, maxY: number) {
        return new Rectangle(minX, minY, maxX - minX, maxY - minY);
    }

    /**
     * 获取矩形边界上与给定点最近的点
     * @param point 
     */
    public getClosestPointOnRectangleBorderToPoint(point: Vector2): { res: Vector2, edgeNormal: Vector2 } {
        let edgeNormal = Vector2.zero;

        // 对于每个轴，如果点在盒子外面
        let res = new Vector2();
        res.x = MathHelper.clamp(point.x, this.left, this.right);
        res.y = MathHelper.clamp(point.y, this.top, this.bottom);

        // 如果点在矩形内，我们需要推res到边界，因为它将在矩形内
        if (this.contains(res.x, res.y)) {
            let dl = res.x - this.left;
            let dr = this.right - res.x;
            let dt = res.y - this.top;
            let db = this.bottom - res.y;

            let min = Math.min(dl, dr, dt, db);
            if (min == dt) {
                res.y = this.top;
                edgeNormal.y = -1;
            } else if (min == db) {
                res.y = this.bottom;
                edgeNormal.y = 1;
            } else if (min == dl) {
                res.x = this.left;
                edgeNormal.x = -1;
            } else {
                res.x = this.right;
                edgeNormal.x = 1;
            }
        } else {
            if (res.x == this.left) edgeNormal.x = -1;
            if (res.x == this.right) edgeNormal.x = 1;
            if (res.y == this.top) edgeNormal.y = -1;
            if (res.y == this.bottom) edgeNormal.y = 1;
        }

        return { res: res, edgeNormal: edgeNormal };
    }

    /**
     * 
     */
    public getClosestPointOnBoundsToOrigin() {
        let max = this.max;
        let minDist = Math.abs(this.location.x);
        let boundsPoint = new Vector2(this.location.x, 0);

        if (Math.abs(max.x) < minDist) {
            minDist = Math.abs(max.x);
            boundsPoint.x = max.x;
            boundsPoint.y = 0;
        }

        if (Math.abs(max.y) < minDist) {
            minDist = Math.abs(max.y);
            boundsPoint.x = 0;
            boundsPoint.y = max.y;
        }

        if (Math.abs(this.location.y) < minDist) {
            minDist = Math.abs(this.location.y);
            boundsPoint.x = 0;
            boundsPoint.y = this.location.y;
        }

        return boundsPoint;
    }

    /**
     * 将egret矩形转化为Rectangle
     * @param rect 
     */
    public setEgretRect(rect: egret.Rectangle): Rectangle{
        this.x = rect.x;
        this.y = rect.y;
        this.width = rect.width;
        this.height = rect.height;
        return this;
    }
   
    /**
     * 给定多边形的点，计算边界
     * @param points 
     */
    public static rectEncompassingPoints(points: Vector2[]) {
        // 我们需要求出x/y的最小值/最大值
        let minX = Number.POSITIVE_INFINITY;
        let minY = Number.POSITIVE_INFINITY;
        let maxX = Number.NEGATIVE_INFINITY;
        let maxY = Number.NEGATIVE_INFINITY;

        for (let i = 0; i < points.length; i++) {
            let pt = points[i];

            if (pt.x < minX) minX = pt.x;
            if (pt.x > maxX) maxX = pt.x;

            if (pt.y < minY) minY = pt.y;
            if (pt.y > maxY) maxY = pt.y;
        }

        return this.fromMinMax(minX, minY, maxX, maxY);
    }
}