Conference bulova::decw_jan-89_to_nov-90

    I think I remember reading about this somewhere else, maybe the DECterm
    conference.  Its a known problem.

    Something most likely tried displaying ReGIS or SIXEL stuff to your window.
    I find that in most cases (but not always) setting my terminal to /noregis
    and /nosixel will stop this from happening.  You can also restore the
    original color maps by choosing first the "Clear display" and then the
    "Reset terminal" options from the Commands pulldown menu.  I find that
    its sometimes hard to read the menu when this happens though.

              Dave

You undoubtedly have a 4-plane system.  VTX does some ReGIS magic to a terminal
when it believes that the term. supports ReGIS.  This causes DECterm to go into
its ReGIS mode, which creates a new colormap and tells the window manager to
install that colormap when the terminal is active (essentially when it has
focus).  This screws up the colors of everyone else on the screen.

BTW, this is really only a bug in the sense that the user is not warned.  There
is not much of any way to avoid doing it, since ReGIS requires there to be
16 colormap entries.

BTW2:  This problem does not show up so badly on 8-bit systems, but it is still
there.  On an 8-plane system, every emulator window that uses ReGIS eats up
16 colormap entries.

As mentioned in .1, the solution is to set your terminal to NoRegis.

..has anyone tried doing any ReGIS or sixel on a 24-plane system?

It doesn't work on my machine and I couldn't find any related QARs.

    
    ReGIS does *not* require 16 colors (a VT240 only uses 4).  This was
    a design decision by DECterm.
    
    And note that /NOSIXEL/NOREGIS works only with "conforming software",
    that is, software which checks the characteristics should not use
    the feature...
    

    This also occurs when using a program such as NMCC/DECnet monitor or
    LAN Traffic Monitor as soon as they change the terminal session
    background color.
    
    Also, the CPU time needed to handle regis based graphics applicatons is
    very high.  This results in very slow graphics updates on the DECterm
    window.  This may cause a problem with customers who want to run these
    types of applicatons under DECwindows. 

>BTW2:  This problem does not show up so badly on 8-bit systems, but it is still
>there.  On an 8-plane system, every emulator window that uses ReGIS eats up
>16 colormap entries.
    
    It is my sincere hope that DECwindows applications will make frugal use
    of scarse colormap resources. In our imaging software, we bend over
    backwards to share colormap entries and take absolutely no more colors
    than necessary to display images with "lots-o-colors" on pseudocolor
    workstations.
    
    This strategy will only pay off if others do the same.
    
    /John
    

    Re: .3 (true color systems).
    
    Here's a QAR I entered a while ago about REGIS and true-color systems.
    So, if you have a 24 plane Firefox system, you're out of luck.
    
    ------------------------------------------------------------------------

QAR # St Sev Pub Cat Maintainer   Component  T Entered-by   Date in     Answer
----- -- --- --- --- ------------ ---------- - ------------ ----------- ------
02001 DF  M  Yes DC  MESSENGER    DECWTERM   M THOMAS       10-NOV-1988  5-JAN
TERMINAL TURNS COMPLETELY BLACK ON TRUE-COLOR SYSTEMS

Site name:        VMS
Product/Version:  VAX/VMS    V5.1               CPU type:  VAX

QAR 02001  Version V5.1      10-NOV-1988 15:28:47.7

-- Submitted by --                      -- DIGITAL contact --
THOMAS
VMS
STAR::THOMAS
GALAXY


Attachments: NONE                      		Customer severity: M
Reproducible at will: Y

CPU        Memory     System device
VAX        lots       DEC

A number of applications will cause the terminal window on a true-color system
to turn completely black.  That is, black foreground on a black background. I
have not found a method to restore the terminal window - it has to be deleted.

I believe that these applications use REGIS.  I can reproduce this at will
simply by starting DECgraph.


Answer for QAR #02001:
------ --- ------- -------
DECterm doesn't include color map support for true color systems.  This
problem will have to be deferred to a future version of the emulator.

				Bob Messenger  5-Jan-1989

    

    
    The ReGIS model is flexible enough to cover all of these problems and
    according to the DECterm Phase 0 documents for V2.0 it should be fixed
    in that release of DECterm.