Function union

docs/app/js/sanddance-app.js:121950–121956

(b5)

        ];
    },
    union (b5) {
        if (b5.x1 < this.x1) this.x1 = b5.x1;
        if (b5.y1 < this.y1) this.y1 = b5.y1;
        if (b5.x2 > this.x2) this.x2 = b5.x2;
        if (b5.y2 > this.y2) this.y2 = b5.y2;
        return this;
    },
    intersect (b6) {
        if (b6.x1 > this.x1) this.x1 = b6.x1;
        if (b6.y1 > this.y1) this.y1 = b6.y1;