[Xastir] Resending maplayer problem

[Tom Russo]

On Tue, Nov 21, 2006 at 12:04:17PM -0600, we recorded a bogon-computron collision of the <jjolin at itol.com> flavor, containing:
> As long as we are on the subject of map layering, I am resending a 
> question I posed a few days ago :
> 
> "Somewhere in all the docs was some suggestions on what map layer to use 
> for radar and the base map (tiger).  I can't seem to find that info.  

You can give it any number between the level number of the map you want 
underneath it and any map you want plotted over it.

Tigermaps from the web server are basically only useful as base layers, so
are best given the layer 0.  That puts them at the bottom of the drawing,
since they'd cover up anything underneath anyway.

You want vector layers to have higher numbers, so they're drawn on to of the
Tiger maps.

The radar maps are transparent except where there's weather, so you want them
to have a higher level than the tiger maps so they're drawn on top.  But the
weather map is opaque wherever there are radar reflections; you might want
your vector layers to be drawn on top of both the radar and tiger maps, and 
if so you'd give vector maps a higher number than both.

> I 
> tried 99999 for the radar map, 
 
Meaning "draw the radar map on top of almost everything.

> but the screen was just black with no 
> tigermap and just the icons.  

There are a couple of things other than the map layer that could be at work 
here.

What version of xastir are you running?  What does the "TRANSPARENT" line
in /usr/local/share/xastir/maps/Online/WMSRadar.geo say?  Are you running a 
24-bit X visual?  (to answer that last one, look at the output of "xdpyinfo"
and see what it says for "depth of root window: ")

>From time to time, the radar map server has changed its transparent pixel value
without rhyme, reason, or warning (and apparently without Gerry being able to
explain!), and when it does then suddenly all the "no reflection" pixels 
become opaque black (actually, a 99.6% shade of gray if we're being precise).
If your WMSRadar.geo file has 0x000000 (as it would have in Release 1.8.1, I
think, but certainly in 1.8.0), then try changing it to 0x010101.  If you're
running a 24-bit X server, that might fix it.  If it says 0x010101, try changing
it to 0x000000 --- the background might have changed again.

The fact that this "99.6% gray"  vs. "100% black" transparent pixel thing
is invisible on 16-bit displays (because the pixel value is compared to the
expected transparent value after both values are converted to bit lengths
appropriate to the display), it's also nearly invisible to Gerry, who is the
one who could fix it when it happens.

If you're running a 16-bit display, I have no idea why you're seeing what
you're seeing, unless you're running an older version of xastir from the 
brief period between the time I fixed 24-bit displays (and broke 16-bit
displays) and the time when I fixed both.

> Someone please enlighten me.
> By the way, my festival server keeps dying.  Anyone else have that 
> problem? "
 
I do not.

-- 
Tom Russo    KM5VY   SAR502   DM64ux          http://www.swcp.com/~russo/
Tijeras, NM  QRPL#1592 K2#398  SOC#236 AHTB#1 http://kevan.org/brain.cgi?DDTNM
"And, isn't sanity really just a one-trick pony anyway? I mean all you get is
 one trick, rational thinking, but when you're good and crazy, oooh, oooh,
 oooh, the sky is the limit!"  --- The Tick