A New Algorithm of Polygon Clipping Against Rectangular Window Based on the Endpoint and Intersection-Point Encoding

Encoding technique for the edges' endpoints of a polygon is proposed based on the essential characteristic of the polygon clipping against rectangular window.Primary and secondary encoding techniques can rapidly identify all of the polygon’s edges in the window and most of the polygon’s edges outside the window as well as classifying the inner vertices and external vertices.Correct clipping result can be obtained based on the line segments in the window and the encoding of intersection-points of polygon edges with those in the window.The special situation that rectangular window and polygon are one containing another is also taken into consideration.Experimental results show that the new algorithm is stable and fast.