| 摘要 |
In a generalized clipping operation, both the objects being drawn and the clipping region are represented as generalized polygons with a non-zero winding number. An object may be entered and clipped by simply tracing its boundary and the clipping region boundary. This tracing may be done by stepping along the edge segments using a curve generation algorithm. Intersections are determined by simply noting whether both clipping boundary and object boundary lie on the same pixel. The time necessary to construct the clipped object is proportional to the length of the object boundary, plus the length of the clipping boundary.
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