Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cwjcc!tut.cis.ohio-state.edu!ucbvax!hoptoad!tim From: tim@hoptoad.uucp (Tim Maroney) Newsgroups: comp.sys.mac.programmer Subject: Re: Help: Using CopyBits for Update Message-ID: <7287@hoptoad.uucp> Date: 13 May 89 17:49:42 GMT References: <1617@neoucom.UUCP> <7254@hoptoad.uucp> <21931@santra.UUCP> <1203@speedy.mcnc.org> Reply-To: tim@hoptoad.UUCP (Tim Maroney) Organization: Eclectic Software, San Francisco Lines: 16 In article <1203@speedy.mcnc.org> kk@mcnc.org.UUCP (Krzysztof Kozminski) writes: >How about this: sometimes the visible and/or clipping regions on the >screen are not rectangular => drawing to the screen is slower than >drawing to an offscreen *rectangular* PixMap due to the extra effort >necessary for the proper clipping of each object drawn. I'm pretty sure the opposite is true. If part of your window is covered, then the reduced Font Manager overhead from not drawing the clipped-out characters makes drawing much faster. Clipping resolution seems to be more than fast enough to make this a win. I have observed this empirically with TOPS Terminal. However, with an offscreen bitmap, every character must be drawn. -- Tim Maroney, Consultant, Eclectic Software, sun!hoptoad!tim "The government of the United States is not, in any sense, founded on the Christian religion." -- George Washington