knight@henson.cc.wwu.edu (Matt J. Scott) (04/10/91)
Please Help! We, at Western Washington University, are now the proud owners of several new DESstation 5000/200. Two of which are expanded with 24-bit color capibility. The problem is that XAllocColorCell will always return FALSE (on the 24-bit machines). So to try and track down the problem I did some digging and testing and discovered that the 24-bit machines do support a DirectColor visual (read/writeable), however, it is NOT the default visual! Does XAllocColorCells only try the default visual? How can we change the default visual from a read only to the read/write visual? Any help would really make my day because many of the applications that run on the 8-bit machines we have will not run on our 24-bit machines, and I have been pulling my hair out trying to fix this!
klee@wsl.dec.com (Ken Lee) (04/10/91)
In article <1991Apr9.174106.2727@henson.cc.wwu.edu>, knight@henson.cc.wwu.edu (Matt J. Scott) writes: |> Does XAllocColorCells only try the default visual? XAllocColorCells() requires a colormap argument. Colormaps must be created for particular visuals. A robust client should make sure that its windows, colormaps, and graphics context fields all use the same visuals. -- Ken Lee DEC Western Software Laboratory, Palo Alto, Calif. Internet: klee@wsl.dec.com uucp: uunet!decwrl!klee
cflatter@zia.aoc.nrao.EDU (Chris Flatters) (04/10/91)
Matt Scott writes: > So to try and track down the problem I did some digging and testing > and discovered that the 24-bit machines do support a DirectColor visual > (read/writeable), however, it is NOT the default visual! Does > XAllocColorCells only try the default visual? XAllocColorCells will only try the colormap you specify as its second argument. If you want to use a non-default visual you must create a private colormap using XCreateColormap with a pointer to the visual you want to use. > How can we change the default visual from a read only to the > read/write visual? Some X servers will allow you to change the default visual at start-up. I don't know if DEC's is one of them: check the man page. Chris Flatters
mikey@sgi.com (Mike Yang) (04/10/91)
In article <9104100234.AA16796@zia.aoc.nrao.edu> cflatter@zia.aoc.nrao.EDU (Chris Flatters) writes: >XAllocColorCells will only try the colormap you specify as its second >argument. If you want to use a non-default visual you must create a >private colormap using XCreateColormap with a pointer to the visual >you want to use. For an example of this, get cpicker.tar.Z from export.lcs.mit.edu:~ftp/contrib. This is my colormap manipulation program, and it searches for a suitable PseduoColor visual to work with. ----------------------------------------------------------------------- Mike Yang Silicon Graphics, Inc. mikey@sgi.com 415/335-1786
mouse@lightning.mcrcim.mcgill.EDU (der Mouse) (04/11/91)
> The problem is that XAllocColorCell will always return FALSE (on the > 24-bit machines). So to try and track down the problem I did some > digging and testing and discovered that the 24-bit machines do > support a DirectColor visual (read/writeable), however, it is NOT the > default visual! Does XAllocColorCells only try the default visual? No; it tries only the visual of the colormap you give it. XAllocColorCells takes a colormap as an argument; that colormap implicitly specifies the visual. (Colormaps are visual-specific.) > How can we change the default visual from a read only to the > read/write visual? This may or may not be possible. Some servers support some way to specify which visual is the default (command-line switches, for example); others don't. I would suggest you not depend on this being possible, for even if it is with your servers, someday someone will want to run the program in question on some other server that doesn't support it. Instead, make sure you find the visual you want and use it when creating your windows and colormaps. der Mouse old: mcgill-vision!mouse new: mouse@larry.mcrcim.mcgill.edu