Path: utzoo!yunexus!stpl!yunccn!nccnat!root From: root@nccnat.UUCP (Paul Shields) Newsgroups: comp.graphics Subject: Re: FAST flood fill Summary: far faster fills found -- References Message-ID: <289@nccnat.UUCP> Date: 5 May 88 01:40:47 GMT Article-I.D.: nccnat.289 Posted: Wed May 4 21:40:47 1988 References: <1210@sbcs.sunysb.edu> <23807@ucbvax.BERKELEY.EDU> <288@nccnat.UUCP> Organization: York University, Toronto Canada Lines: 34 In article <288@nccnat.UUCP>, I write: > There's a paper kicking around somewhere by someone at Berkeley, circa 1986, > analyzing all previously known fill algorithms and presenting a new one. Fishkin, Kenneth P., and Barsky, Brian A. 1985. "An Analysis and Algorithm for Filling Progagation", Graphics Interface '85. The algorithm takes care of U, S, and W turns. > A friend of mine at IBM has optimized this alogorithm, achieving high- > performance fills for multiply-connected regions: > - worst case 1.5 visits per pel; > - best case 1.0 vists per pel; > - avg = 1.05. > > For simply-connected regions, it's 1.0 visits per pel always. He is, Ian Ameline, Development Analyst, IAD, IBM Canada Lab, TOROLAB2(AMELINE). I have a drop-box here for him, ian@nccnat.UUCP. I believe his optimizations include improved handling of some types of regions and use of memory management routines to reduce thrashing, since Fishkin and Barsky also report avg 1.05 visits per pel, 1.5 worst case, but admit that for simply-connected regions it's not always optimimal. Unfortunately, the (optimized) code is proprietary. But I _may_ be able to convince him to hint at what hasn't been taken care of in the other algorithm. In any case, you can see it at work in the IBM ImagEdit software if you're interested. Disclaimer: I have no connection with IBM or any of its products. Please do not take the above paragraph as an advertisment. -- Paul Shields, shields@yunccn.UUCP If you think you have a subconscious, or yunccn!nccnat!root you have a software integration problem.