On Tue, Feb 1, 2000 10:34 AM, Lex Spoon lex@cc.gatech.edu wrote:
It's doable on Unix as well. So the big three are covered. We just need a primitive to specify where the shape bitmap is.
Lex
Has anyone looked at implementing the QuickDraw region algorithm in Squeak?
The patent has *certainly* run out since it has been more than 15 years since the Mac was introduced. I'm willing to bet that QD regions are STILL the most efficient and fastest way to describe an irregular region, and it would likely speed up Squeak graphics by a good bit to use the algorithm as a primitive, which is no longer covered by any patent, AFAIK.
------------------------------------------------------------------------- Lawson English. Squeak, snore, etc. Check out http://www.squeak.org -------------------------------------------------------------------------
Lawson English writes:
Has anyone looked at implementing the QuickDraw region algorithm in Squeak?
The patent has *certainly* run out since it has been more than 15 years since the Mac was introduced. I'm willing to bet that QD regions are STILL the most efficient and fastest way to describe an irregular region, and it would likely speed up Squeak graphics by a good bit to use the algorithm as a primitive, which is no longer covered by any patent, AFAIK.
The Atkinson patent is:
US4622545: Method and apparatus for image compression and manipulation
It was granted November 11, 1986, so it hasn't yet been 15 years. It doesn't matter, though, since patents issued prior to 1995 have a lifetime of 17 years. Bottom line - still not available, won't be until almost 2004.
The Apple method is a little rough in its rawest implementation due to the use of scanline buffers - making it really efficient would probably require the kind of time and brainpower Apple has applied to it over the years. It's also notable that QD regions did not carry forward to QDGX, likely because of the inherent resolution-dependence.
There are unencumbered alternatives to QD regions that are still pretty efficient, including the shape algebra documented in GGII/1.9 by Steinhart. I have a cleaned-up C implementation that can be readily converted to Smalltalk - if someone else wants to hack BitBlt to use it. It would certainly be nicer to use a region as mask rather than a bitmap for many things, and it would also be helpful to support region algebra.
-- Duane
=================================================== Duane Maxwell dmaxwell (at) entrypoint.com CTO http://www.entrypoint.com EntryPoint, Inc. (858)348-3040 FAX(858)348-3100
Information contained herein is my personal opinion and not necessarily that of EntryPoint. ===================================================
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