Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!cmcl2!ccnysci!alexis From: alexis@ccnysci.UUCP (Alexis Rosen) Newsgroups: comp.sys.mac.programmer Subject: Re: Saving area under dialog boxes (Re: WingZ) Message-ID: <1888@ccnysci.UUCP> Date: 7 May 89 05:51:08 GMT References: <598@eutrc3.UUCP> <1774@ccnysci.UUCP> Reply-To: alexis@ccnysci.UUCP (Alexis Rosen) Organization: City College of New York Lines: 23 In article davidl@intelob.intel.com (David Levine) writes: >OK, I've been following this discussion for a while, and I don't >understand the problem. Yes, it would be a Bad Idea to CopyBits from >the SCREEN to a buffer and then restore after the dialog goes away. >But the original poster seems to have been talking about the >application copying the affected area of ITS OWN WINDOW to a buffer >and then restoring ITS OWN WINDOW. What could be wrong with that? Nothing at all, except that there's usually no cheap way to tell what part of your window is really visible and what's covered (and what needs updating already). Whatever's not current would need to be drawn the slow way anyway. So the best solution (for speed) is very close to that. You draw everything to an off-screen bitmap and then copybits (or copyPix) it to the screen. For example, FoxBase+/Mac does that. So do many other programs. As is often the case, it's really a tradeoff between memory and speed. --- Alexis Rosen alexis@ccnysci.{uucp,bitnet} alexis@rascal.ics.utexas.edu (last resort)