[Xastir] Compressed objects creep a little after creation?

[Tom Russo]

On Thu, Nov 09, 2006 at 10:39:35AM -0800, we recorded a bogon-computron collision of the <archer at eskimo.com> flavor, containing:
> On Thu, 9 Nov 2006, Tapio Sokura wrote:
> 
> > ...but the side effects are a bit more annoying to me. The station
> > info box, for example, gathers the previous positions on it, so it
> > looks like the object is moving when it in reality isn't moving.
> > Anyway it seems to be a cosmetic problem, mostly.
> 
> I'm pretty sure you're right that it's some sort of rounding error.
> Xastir creates the object string and transmits it, but also throws
> it back into its own decoding logic which is where it gets added to
> the station database and such.  Seems like a round-about way of
> doing it, but it was the simplest at the time.  You're certainly
> welcome to put in a bug report about it.

and has the extremely convenient side-effect that objects heard on the
server port claiming to be from xastir's own call-sign are accepted as if
they had been created in xastir itself --- making it possible for external
programs to generate objects.  See, for example, William McKeehan's
script for creating objects using a preset list of waypoints (e.g. creating 
objects for racers as they pass checkpoints).

If the fix for this rounding problem were to involve not feeding objects back
through the decoding logic, the cure would be worse than the disease.

-- 
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