ph@miro.Berkeley.EDU (Paul Heckbert) (09/11/88)
Does anybody know of any references to in-place zoom algorithms? That is, methods for zooming a picture up or down in resolution with overlapping source and destination windows, that doesn't step on itself (suffer from feedback). Doing it right, especially with filtering, is a fun problem. Has anybody seen or heard of algorithms like this before? I just wrote such a beastie and I'm curious how novel it is. Paul Heckbert, CS grad student 508-7 Evans Hall, UC Berkeley UUCP: ucbvax!miro.berkeley.edu!ph Berkeley, CA 94720 ARPA: ph@miro.berkeley.edu
david@epicb.UUCP (David P. Cook) (09/13/88)
In article <26040@ucbvax.BERKELEY.EDU> ph@miro.Berkeley.EDU (Paul Heckbert) writes: >Does anybody know of any references to in-place zoom algorithms? >That is, methods for zooming a picture up or down in resolution with >overlapping source and destination windows, that doesn't step on itself >(suffer from feedback). Doing it right, especially with filtering, is >a fun problem. Has anybody seen or heard of algorithms like this before? > >I just wrote such a beastie and I'm curious how novel it is. > >Paul Heckbert, CS grad student >508-7 Evans Hall, UC Berkeley UUCP: ucbvax!miro.berkeley.edu!ph >Berkeley, CA 94720 ARPA: ph@miro.berkeley.edu ... Probably not that novel, but your term BEASTIE is very accurate... The reason you do not see that many versions of in-place zooms being used in various software is that the time factor for performing the zoom is large. It (of course) can be accomplished by 'duplicating' your memory plane and performing the zoom from the backup plane to the visible plane. This is the most desirable (if you have the memory for it) because it requires the least amount of BEASTIEness. Otherwise, intelligent scanners with a couple of scan-line buffers work (intelligent scanners change their direction dynamically during the zoom, copy, move etc..). Just interested, however, as to how exactly you performed your BEASTIE code (ie.. did you use a cellular approach, scan line approach, intelligent scanner approach etc..)? -- | David P. Cook Net: uunet!epicb!david | | Truevision Inc. | "Specialization is for insects" | | Indianapolis, IN | -- Timothy Leary | -----------------------------------------------------------