| 摘要 |
The method 600 renders a self-overlapping polygon, wherein the polygon is a set of one or more closed curves each comprising line segments. The method performs, for a currently scanned pixel that overlaps both sides of a line segment of the self-overlapping polygon within a currently scanned scanline, the following steps. The method 600 decomposes 618 that portion of the polygon that lies within the currently scanned pixel into a number of closed loops comprising at least those portions of those line segments that lie within the currently scanned pixel, the closed loops are such that when they are combined the combination is substantially equivalent to that portion of the polygon that lies within the currently scanned pixel. The method 600 combines 623 incrementally the closed loops and determines one or more one winding count values representative of respective weighted averages of winding counts of the combined closed loops. The method 600 then determines 622 a real opacity of the currently scanned pixel according to a predetermined fill rule utilising an intrinsic opacity of said polygon and the one or more winding count values. The method 600 finally renders 624 the currently scanned pixel with the determined real opacity.
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