public Region() throws IllegalStateException {
if (canvas_width < 0 || canvas_height < 0) {
throw new IllegalStateException("The canvas size has not been set appropriately.");
}
// initialize position values
this.left = canvas_width + 1;
this.top = canvas_height + 1;
this.right = -1;
this.bottom = -1;
this.image = null;
this.color =
ColorConverter.RGB.rgb(
(int) (Math.random() * 255), (int) (Math.random() * 255), (int) (Math.random() * 255));
}
