[Therion] Custom map connections

[Tarquin Wilton-Jones]

Hi folks,

I have a challenge, presented to me by some users of one of our surveys.

We have a cave with layers horribly stacked above each other (10
passages all crossing the same point!). Simple solution; use map offsets
to put them all side by side. Use map connection arrows to show what
connects to what.

That's all good, but they find the default connection arrow hard to see.
I can redefine l_mapconnection to create my own arrows. Great!

But here's the challenge; they want us to show the difference between an
unimportant connection, and a major "follow this route" connection. Eg.
minor ones in grey, major route in red.

I have tried everything I can think of with the mapconnection point: id,
scale, rotation, -attr etc., but Therion is not creating a
p_mapconnection. it creates a l_mapconnection, and passes it a path to
create the line. The attributes are all completely ignored.

Normally, I would use "-attr type major", but that cannot work here,
because Therion just ignores it. In my opinion, this is a limitation
that should be fixed.

The only solution I can think of, is to put *two* mapconnection points.
The l_mapconnection code can then see if the current path matches the
previous path, and if so, draw it in red. But this is such a horrible
hack, and prone to failure in future if someone does not realise why
there are two points, and why they have to follow on from each other.

Can anyone think of a better workaround?

Cheers,

Tarquin