[GRASS5] Window Extents and region settings in X...

Eric G. Miller egm2 at jps.net
Wed Feb 28 21:15:36 EST 2001

On Wed, Feb 28, 2001 at 06:09:49PM +0100, Radim Blazek wrote:
> I think that region handling should be changed somehow. But that's task 
> for g51. My suggestion (not thought over deeply yet) is to distinguish region
> used by:
> 1) modules creating new data  
>     which would use current region saved in WIND
> and
> 2) monitor + display/query modules
>     which would use region stored in memory of monitor.
>     Each monitor would have it's own region.
> Monitor region would always cover whole area of monitor.
                                    (or frame ...)

> New functions could be used for manipulating currend WIND, for example
> display WIND on monitor (by rectangle), set WIND to region of selected
> monitor, create WIND interactively on monitor, ...
> Some problems with one shared region as is used now:
> - user cannot rely on current state of monitor, if region was changed for
>    a while, d.erase must be run even if region was reset to original size.
> - it is impossible to run some script on data and at the same time
>    explore maps on monitor (I forgot several times about it and I was very
>    surprised why created data are incomplete)
> - write access to database is always required even if user want only
>    read/explore data.
> - (more?)
> I'm waiting for your criticism.

More or less sounds like a decent idea.  There's the tricky issue of
resolution.  Would we calculate resolution based on a scaling from
screen resolution, window extents and mapunit extents?  A little tricky
with things like polar wrap around...  Anyways, your right to say it
should be later.  I work on a little clipping code for d.area so it's
output is "conforming"...

Eric G. Miller <egm2 at jps.net>

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