[GRASS5] v.digit zooming

[Hamish]

Hi,


I was looking to fix the -v.digit zooming leaving the region settings in
a mess- bug..

It's pretty easy to keep a old_region in memory and then restore upon
clean exit, but I thought it might be best to address the underlying
problem before doing that.

The issue is digitizing with a raster backdrop at somewhat coarse
resolution. If the region settings no longer line up with the raster
grid either in space or in resolution then the cells can display in the
wrong place (up to half a cell at the same res).. You then digitize off
of a raster which isn't displaying where you thought it should....
??? Will oddly numbered fractional region settings and resolution mean
that redrawing the raster will take a lot of resampling and slow things
down?

d.zoom deals with it this way:   grass6/display/d.zoom/set.c

It preserves resolution setting over boundary settings. I guess that is
the approach we should use here too? or is this a
G_adjust_Cell_head(,0,0) bug?


After the above problems are sorted we can begin fixing the special
lat/lon cases.



Hamish