Xiaolin Wu's line algorithm: Difference between revisions

Revision as of 09:08, 14 December 2012

Revision as of 02:15, 18 December 2012

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'''Xiaolin Wu's line algorithm''' is an [[algorithm]] for line [[Spatial anti-aliasing|antialiasing]], which was presented in the article ''An Efficient Antialiasing Technique'' in the July 1991 issue of ''[[Computer Graphics]]'', as well as in the article ''Fast Antialiasing'' in the June 1992 issue of ''[[Dr. Dobb's Journal]]''.

[[Bresenham's line algorithm|Bresenham's algorithm]] draws lines extremely quickly, but it does not perform anti-aliasing. In addition, it cannot handle theany casecases where the line endpoints do not lie exactly on integer points of the pixel grid. A naive approach to anti-aliasing the line would take an extremely long time, but. Wu's algorithm is quitecomparatively fast, (itbut is still slower than [[Bresenham's, though)line algorithm|Bresenham's algorithm]]. The basis of the algorithm isconsists toof drawdrawing pairs of pixels straddling the line, each coloured according to proximityit's distance from the line. Pixels at the line ends are handled separately. Lines less than one pixel long should beare handled as a special case.

An extension to the algorithm for circle drawing was presented by Xiaolin Wu in the book ''[[Graphics Gems]] II''. Just like the line drawing algorithm is a replacement for Bresenham's line drawing algorithm, the circle drawing algorithm is a replacement for Bresenham's circle drawing algorithm.