Collision detection

Code

var rtop = new Point(100, 100);
var rbot = new Point(300, 300);

var rect = new Rectangle(rtop, rbot);
var prect = new Path.Rectangle(rect, 5);

prect.fillColor = 'red';
prect.strokeWidth = 2;
prect.applyMatrix = false
prect.onMouseDrag = function(event){
    this.position += event.delta

    if (prect.intersects(qrect) == true){
        this.opacity = 0.2
    } else{
        this.opacity = 1
    }
}

rtop = new Point(200, 200);
rbot = new Point(400, 400);
rect = new Rectangle(rtop, rbot);
var qrect = new Path.Rectangle(rect, 5);
qrect.strokeColor = 'black';
qrect.strokeWidth = 2

rtop = new Point(500, 500);
rbot = new Point(600, 600);
rect = new Rectangle(rtop, rbot);