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Conference bulova::decw_jan-89_to_nov-90

Title:DECWINDOWS 26-JAN-89 to 29-NOV-90
Notice:See 1639.0 for VMS V5.3 kit; 2043.0 for 5.4 IFT kit
Moderator:STAR::VATNE
Created:Mon Oct 30 1989
Last Modified:Mon Dec 31 1990
Last Successful Update:Fri Jun 06 1997
Number of topics:3726
Total number of notes:19516

981.0. "XAllocColorCells of ALL CELLS?" by KASINO::TALLETT (Window mangler...) Tue Jun 20 1989 06:32

    Hi folks!
    
    	Why can't I allocate all the planes of a workstation in
    	one XAllocColorCells call if I am using a private colormap?
    	More specifically, the following code barfs on a 4-plane
    	server (it is supposed to allocate 16 colours):
    
        colormap = DefaultColormap(dpy, screen);
    
        if(XAllocColorCells(dpy, colormap, False, planes, 4, &pixel, 1)==0){
            if((colormap = XCreateColormap(dpy, root, visual, AllocNone))==0){
                printf("Failed to create private colormap\n");
                exit(1);
                }
            if(XAllocColorCells(dpy, colormap, False, planes, 4, &pixel, 1)==0){
            printf("Couldnt alloc color cells\n");
            exit(1);
    	    }
    	}
    
    	I also tried changing the "4"s above to "8"s and running on an
    	eight plane workstation (GPX) with the same problem. I can
    	grab 3 or 7 planes respectively, but not all the planes. Note
    	AllocAll works in the XCreateColormap, but then I have to hard
    	code the plane masks - yuk!
    
    	Did I do something wrong? Does XAllocColorCells not want to give
    	me the cursor entries? (If so, why does XCreateColormap(AllocAll))
    	Is this supposed to work?
    
    Thanks in advance!
    Regards,
    Paul Tallett
    CEC Karlsruhe
    West Germany
T.RTitleUserPersonal
Name		DateLines
981.1Bug in common server? (Works on MIT servers)KASINO::TALLETTWindow mangler...Tue Jun 20 1989 12:2210
    What is more, the 8-plane version of .0 WORKS on an 8-plane
    colour-PMAX! I can allocate all 8 planes of the PMAX in one
    XAllocColorCells call.
    
    The plot thickens. I just checked the size of the colormap.
    On a VMS GPX it is 256, but on an Ultrix GPX it is 254 !!
    
    C'est une burg n'est ce pas?
    Paul
981.2A few answersDECWIN::FISHERBurns Fisher 381-1466, ZKO3-4/W23Wed Jun 21 1989 11:3620
Q'est que ce une burg?

In any case, I can answer the last question easily enough.  Remember that
a GPX uses the last two colormap entries for the cursor color.  Ultrix and
VMS chose to deal with that problem differently.  We pre-allocate 254 and
255 in the default colormap so you don't normally overwrite them.  However
if you create a cmap of your own, you are free to use all 256 colors.  However,
you will trash the cursor with 254 and 255.  Ultrix chose to just say that
there are only 254 entries so the last two never get written.  If you think
the VMS decision is wrong, mea culpa.  I had just gotten told so often that
image people need  all 256 that I chose to do it that way.

As to the allocation, I would not be too surprised if the pixel value is
being allocated first, and maybe from the top.  Then there are not enough
planes to give you.  QAR it if you think it is a bug.

Of coures doing AllocAll would accomplish the same thing.

Burns
981.3Up to 7 planes.NYMPH::ZACHWIEJAIt's 85% or bustThu Jun 22 1989 12:2413
    
    I have the same problem on an 8-plane VS2000 running VMS 5.1.
    
    I try and allocate 256 colors from the default colormap asking for
    8 planes and 1 pixel,  I don't expect it  too  work  because,  the
    default colormap probably already has some cells allocated.
    
    I then fall back to creating my own colormap,  and making the same
    request,  x$alloc_color_cells, 8 planes, 1 pixel.  It  also  fails.
    I can get up to 7 planes.
    
    I'll submit a QAR.  _sjz.