Abstract: This paper proposed a new method for line clipping with a polygon．The method gets the intersection points of a polygon and a line by matrix multiplication．For a set of line segments,the algorithm of this paper tests it by a bounding box that included the polygon to discard the line segments which do not intersect the box,then the algorithm introduces homogeneous coordinates,and makes a group of matrixes and applies the matrixes multiplication to the polygonal window and the straight line to make the continuous affine transformations,and gets the intersection points of the window and straight line from the matrix．Having sorted and matched the points of intersection,the algorithm of this paper obtains the result of the polygon clipping the line segment．The experiment shows that the new method is effective,and the speed is improved.

Key words: Clipping,Affine transformation,Matrix,Polygon,Window