public void zoom(int amount) {
		int direction = amount / Math.abs(amount);
		
		for (int i=1; i<=Math.abs(amount); i++) {
			if (radius > originalRadius || direction > 0) {
				radius = radius + 30*direction;
			}
		}
		
		this.windowCoordsUpdated = false;
		updateCenterCoordinates();
	}