[Xastir] New code testing

[Curt Mills, WE7U]

On Wed, 23 Jul 2003, Stephen West-Fisher wrote:

> HSP all the time into a DJ580, magmount antenna on the roof.
> Yes, the laptop is reliable, but slow.
>
> I'll be testing again in my truck later this week on the same routes.

If you could try it with just the GPS plugged in instead of the
radio, perhaps creating a Serial GPS interface for the task, that
might tell us whether the HSP code is at fault.


> I still think it is the combination of slow laptop/map redraw/low zoom
> level since a longer trip at higher zoom had no faults. My thoughts are
> that the map needs redrawn, so a redraw is started. By the time the map
> redraw is finished, I'm off the edge again. Due to screen aspect ratio
> this happens more on north/south routes. This really only happens at
> higher speeds, when I'm on streets at less than about 50mph, it doesn't
> seem to happen.

Ok.  It's possible that the TrackMe code needs to initiate a map
interrupt in this case, so that Xastir can try to keep up.  In that
case you might not get a complete redraw before you get a map
interrupt (depending on speed/zoom level/number & type of maps
selected), so the maps drawn into memory won't even show up on the
display.  Xastir might appear to be doing nothing, but in fact would
be frantically drawing maps into a pixmap, then getting interrupted
before you get to the copy-to-the-display stage, then starting the
process all over again.  It might alleviate the segfaults you're
seeing though, so it's probably a step in the right direction.

There's not a lot we can do about that except suggest running on a
laptop capable of redrawing in the time allotted.  It seems to me
that we should do the map draw interrupt in this case though, so
that Xastir doesn't get bogged down trying to draw maps that you're
already past, queuing up more maps to load as it goes.

Another thing we _could_ do is to copy the maps up to the display as
each map is loaded into memory.  This would slow things down
slightly overall, but would at least give you partial maps as you
were going along.  Problem is, if we interrupt the map drawing when
you get to the edge, you'd never get the weather alerts/ symbols/
tracks drawn on top of the maps either, so you wouldn't even get to
see where you were on the map.

Ideas anyone?

-- 
Curt Mills, WE7U                    hacker_NO_SPAM_ at tc.fluke.com
Senior Methods Engineer/SysAdmin
"Lotto:    A tax on people who are bad at math!"
"Windows:  Microsoft's tax on computer illiterates!" -- WE7U
"The world DOES revolve around me:  I picked the coordinate system!"