[PyFeyn] PyFeyn adjust fonts

[Georg von Hippel]

Hi Ian,

to draw on an existing canvas, you can initiate a FeynDiagram instance 
drawing to that canvas by passing the canvas to the FeynDiagram 
constructor as in

   fd = FeynDiagram(canvas=my_preexisting_canvas)

and then draw to that canvas using

   my_canvas_that_has_now_been_drawn_on = fd.drawToCanvas()

which is exactly what the draw method does internally before writing the 
resulting canvas to a file.

The interface to add text attributes to LineLabel objects isn't currently 
exposed, so unless you want to start fiddling with PyFeyn internals, you'd 
have to stick to using LaTeX commands; adding \color{green} to the TeX 
code in addLabel should work, as long as you call

   pyx.text.defaulttexrunner.preamble(r"\usepackage{xcolor}")

before any other commands. (You can also add lines defining your own 
custom colours to the preamble, and then use those).

Best,

    Georg



On Tue, 15 Nov 2016, Ian Brock wrote:

> Hi Georg,
>
> Thanks for the information. I am still finding my way around this stuff.
>
> Suppose I want a green electron line and the label to be also green. For now I do:
> fa2 = Fermion(vtx1, out1).addArrow().addLabel(r'$\Pe(k^{\prime})$')
> fa2.setStyles([FORESTGREEN])
> However, how can I get \Pe to also be green?
> I am not sure how to change the pyx.text.defaulttexrunner attributes or where I can find documentation on that.
>
> Another question: Can I draw the diagram on a canvas rather than directly into a file? I see there is a command drawToCanvas(), bit I am not sure if I have to initialise the canvas and if so how?
>
> Best Regards
> Ian
>
> Ian C. Brock | Physikalisches Institut, Universität Bonn | Nußallee 12 | D-53115 Bonn
> Tel. +49 228 733616 | Email: brock at physik.uni-bonn.de <mailto:brock at physik.uni-bonn.de>

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