Black and White monitors

Ken Sibley ksibley at
Fri Mar 18 10:00:25 EST 1994

> From grass-lists-owner at Fri Mar 18 08:48:35 1994
> Somebody please answer my request about Black and White terminls.
> d.mon fails to open up a monitor on Black and White monitors.
> Do we have to create a seperate driver for B&W terminals?
> Nalneesh Gaur, River Forecast Center, TULSA  
I did not respond before since I assumed someone else would know more about
this subject than I, but since they did not.  Here is what little I know.
The existing XDRIVER attempts to open a window while requesting 216
colors from the root colormap.  If 216 colors are not available then
it creates its own colormap filling 216 of the available 253 color cells.
This prevents it from running on B&W monitors.  I do beleive that you
can modify the existing XDRIVER to only request 2 colors (1 bit plane)
to work on a B&W monitor.  This will allow you to display a single 
vector map with no overlays.  It will not allow you to display
raster maps as any raster map with more than 2 catagories will require
more than 2 colors.

Ken Sibley
ksibley at

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