[GRASS-dev] Scale display in GRASS Monitor

[Glynn Clements]

Markus Neteler wrote:

> the GRASS monitor does not show the approx. scale of the map.
> In the past I introduced that one or two times but it was
> reverted. Since every GIS shows a scale on screen, it is
> hard to explain why GRASS doesn't do it.
> 
> So I launch a new attempt to get the scale (back) on top
> of the GRASS monitor... I know about dpi and all this stuff
> but we really don't need centimeter precision :-)
> 
> Opinions?

The movement towards gis.m and the PNG driver only makes this even
less feasible now than it was in the past. What is the DPI of a
PNG/PPM file?

I'm willing to extend the driver protocol so that such a feature
becomes possible, if you can:

1. Persuade me that even at this late stage in its life, XDRIVER is
still worth extending.

2. Convince me that it really doesn't matter that the reported scale
will be *significantly* inaccurate for most users.

[For me, xdpyinfo reports 75x75dpi. Given that the screen resolution
is 1920x1440, that implies that I have a 32" monitor. In reality, the
monitor is (nominally) 22", so the actual resolution is more like
110dpi. IOW, the reported resolution has a relative error of ~50%.]

3. Tell me what resolution the PNG driver should report.

-- 
Glynn Clements <glynn at gclements.plus.com>