private Point2D getOffsetFromScreenCenter(int x, int y)
	{
		
		double xOffset = (x - canvas.getSize().x/2)/(double)(canvas.getSize().x)*2.0;
		double yOffset = (y - canvas.getSize().y/2)/(double)(canvas.getSize().y)*2.0;
		
		return new Point2D.Double(xOffset, yOffset);
	}