Scan-conversion process and processor for converting a graphic primitive

Abstract

A scan-conversion processor converts a graphic primitive defined by its outline to pixel data by storing edge data blocks containing the y-coordinates of the vertices of each edge, the x-coordinate of the lower vertex, and x-coordinate increment data. The edge blocks are linked in ascending order of teir minimum y-coordinate values into edge chains representing consecutive series of upward- or downward-inclined edges. Information indicating the edge inclination can also be stored in each edge data block, to support use of the non-zero-winding algorithm to discriminate between the interior and exterior of the graphic primitive. since it requires relatively little memory space, the scan-conversion processor, including its memory, can be implemented as a single integrated circuit on a semiconductor chip.