containsPoint(p) {
        return p.x >= this.x &&
            p.x < this.x + this.w &&
            p.y >= this.y &&
            p.y < this.y + this.h;
    }
Determines if the given point is in the receiving rect or not.

Note that the top and left of the rectangle are inclusive, but the bottom and right are exclusive.

@param {!Point} p The query point.
@returns {!boolean}