function computeOutCode (x, y, xmin, ymin, xmax, ymax) {
		var code = 0;
		if (y > ymax)
		    code |= TOP;
		else if (y < ymin)
		    code |= BOTTOM;
		if (x > xmax)
		    code |= RIGHT;
		else if (x < xmin)
		    code |= LEFT;
		return code;
	}
Implementation of the cohen-sutherland algorithm