$x_1<x_{min}$ AND $x_2<x_{min}$	(line is left to the clipping window)
$x_1>x_{max}$ AND $x_2>x_{max}$	(line is right to the clipping window)
$y_1<y_{min}$ AND $y_2<y_{min}$	(line is under the clipping window)
$y_1>y_{max}$ AND $y_2>y_{max}$	(line is over the clipping window)