[PyFeyn] [cedar] Bug report: Cannot draw straight gluino lines

[Andy Buckley]

Sue Ann Koay wrote:
> Thanks for the speedy response. I was actually hunting for a
> python-to-diagram interface because I wanted to write python script
> that converts a feynman diagram specification given some dot-like
> textual input, into a diagram. I could only think of an algorithm for
> tree-level diagrams, but thanks to pyfeyn it works nicely and I'm
> happy.

That sounds very neat! What's it for? :) If you're doing a lot of these
conversions you might want to run it in draft mode (or just disable the
3D gluons/gluinos) for speed - it takes a lot of CPU time to calculate
the crossing points of gluon-type lines.

When we get round to making a next version, I think profiling and
optimising this will be one of the major issues - if you can help or
have any requests I'd be very grateful.

> One feature that would really be nice would be for the text to be
> rotatable (I tried the angle specification but it doesn't seem to have
> an effect). In fact it would be lovely for long text lines to know how
> to align themselves to the lines they are attached to (of course I can
> also calculate tangents and set them by hand), because otherwise they
> overlap with the lines themselves.

I can't remember offhand what the angle attribute does - I have a
feeling that it controls the angle of the text offset rather than the
angle of the text baseline itself. We can think about adding this: if
you can send me an example graphic (or code) with such long lines then
I'll have a better idea of what you want.

Andy