[GRASSLIST:3161] Re: [GRASS5] Re: Grass GUI

[Glynn Clements]

Roger Miller wrote:

> It includes changes to a small number of library functions that allows more 
> flexibility.  It arranges for G_get_window and other window functions to 
> always provide information about the window settings of the currently 
> selected monitor, not from the database WIND files.

How does it handle the case where no monitors are running?

Also, I'm not sure what this change would enable. You still can't have
multiple sessions using the same mapset directory due to the lack of
any finer-grained locking.

If the locking issue were solved, the simplest way to support multiple
sessions on a single mapset would be to merge the data in the WIND
files with most of the data in $GISRC into a "session" file.

However, note that there is an inherent tension between having
multiple sessions on a single mapset and remembering a mapset's region
between sessions.

> The final capability I 
> intended to add before I presented the program allows each monitor to be 
> associated with an entirely different GIS environment.  That allows a user to 
> display and work with data from more than one mapset and more than one 
> database location at the same time.

AFAICT, the only thing that imposes a "one session per user" limit is
the way that $GISRC is managed. You can have multiple sessions,
provided that you create a new $GISRC file for each one.

And the only thing which ties a monitor to a specific location is
XDRIVER's redraw code, and I'll remove this if it ever gets in the way
of anything.

-- 
Glynn Clements <glynn.clements at virgin.net>