Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!wuarchive!zaphod.mps.ohio-state.edu!mips!sgi!shinobu!odin!sgihub!dragon!eukanuba.wpd.sgi.com!mikey From: mikey@eukanuba.wpd.sgi.com (Mike Yang) Newsgroups: comp.sys.sgi Subject: Re: SGI's migration to X Message-ID: <1990Aug31.162941.6984@relay.wpd.sgi.com> Date: 31 Aug 90 16:29:41 GMT References: <208@voodoo.UUCP> Sender: news@relay.wpd.sgi.com ( CNews Account ) Reply-To: mikey@sgi.com Organization: Silicon Graphics, Inc. Lines: 54 There is no question that the X window system model is quite different from that of SGI. To address some of your points: 1. Colormaps The colormap mechanism is general enough to support colormaps of various depths. Therefore, RGB values are specified as [0,65535] rather than [0,255]. And this makes sense. Remember, the Xlib routines that you use (e.g. XStoreColors) are based on the protocol, which has remained consistent for all revisions of X11. It would have been silly for the X designers to limit this and assume that no hardware vendor would come up with a colormap visual with fewer than 8 planes. The other advantage to this model is that if you then compile your program and run it on a machine with a different size colormap (e.g. a 4 plane DEC system), it will run the same. Remember, X programs are suppose to be portable and work generally the same way on different hardware situations. 2. Local image storage and sending the result to the server Because X is based on a client/server model, your image processing client can build its own data but then needs to send it to the server for display. This is different from GL, where your client application can write directly to the screen hardware. X requires this indirection because X clients can run on remote hosts. As for your specific problem, images can be sent to the server in quantities greater than one pixel. If you use XCreateImage to create a local image data structure, XPutImage will send any region (including the whole thing) to the server. 3. Window placement The X model is that there is a window manager which governs the handling of windows. Its policy varies from window manager to window manager. Apparently, the one you're using is configured for "user positioning," meaning that windows are interactively placed by the user when they are mapped. Clearly, people who are used to the GL model and who have had prior GL experience will find X to be quite different and initially, difficult. But this is true when learning anything new. Personally, I found the GL model different and difficult because I was used to X. There is going to be a learning curve for people migrating to X. The best way to reduce this is to find people knowledgable about X and ask them questions. Believe it or not, this set of people is much greater than the X Consortium. ----------------------------------------------------------------------- Mike Yang Silicon Graphics, Inc. mikey@sgi.com 415/335-1786