[metapost] Prevent a pen from leaking
Philipp von Weitershausen
philipp at weitershausen.de
Mon Apr 27 21:19:11 CEST 2009
before I begin I should point out that I'm a MetaPost novice. I've tried
to find an answer for my problem in the numerous excellent tutorials out
there but have failed so far.
I'm trying to extend the excellent FeynMF package to allow vertex
decorations to be drawn with an optional user-specified width. For this
I've extended the following macro (my addition is the 'if' after the
vardef vdraw_vertex suffix v =
if known v.decor.shape:
% NEW: user-specified width
if known v.decor.wd:
pickup pencircle scaled v.decor.wd;
... % drawing of the actual vertex shape happens here
The problem I now have is that the scaled pen *sometimes* leaks to
outside this macro, thereby affecting the line width of other objects
that are drawn. Helpful people have already pointed me to "draw ...
withpen ...". This is not very useful here, however, because the
vdraw_vertex macro above doesn't actually do the drawing itself, it
calls upon other macros to do that.
To fully reproduce the problem, one may obtain my modifications to
FeynMF from my git repository:
git clone http://iktp.tu-dresden.de/~philipp/feynmf.git
Here's an example document that reproduces the problem I see in my
Any pointers would be much appreciated.
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