| 摘要 |
<p>A method of clipping images in the form of polygons falling outside an image window comprises the steps of assigning to each polygon vertex a Sutherland-Cohen or equivalent outcode so that a pair of outcodes for two vertices corresponds to a polygon edge; and executing a separate routing for each outcode pair to determine the vertices of any new polygon lying within the image window. The advantages are that redundant calculations are avoided, in particular, any window-edge intersections performed contribute to the clipped polygon (which is not the case for all polygon clipping methods). Intermediate values are stored and reused.</p> |
