[metapost] wrong bounding box with pencircle

[Taco Hoekwater]

On Jun 23, 2013, at 1:01 AM, Stephan Hennig <mailing_list at arcor.de> wrote:

> Hi,
> 
> Am 22.06.2013 19:30, schrieb Boguslaw Jackowski:
> 
>> I believe that it is a long-standing issue.
>> [...]
>> Then, the problem several times "payed a visit" to the MF/MP discussion
>> list. In particular, the problem was disscussed in the thread
>> "some question about pens", triggered by Stephan Hennig 01 Apr 2008. :-)
> 
> Oh, I don't remember any more.  But I do remember MetaPost "recently"
> fixing some pen and bounding box related issue, which (the fix) even
> affected Knuth.  ...  OK, that must have been in 2007,
> <URL:http://tug.org/pipermail/tex-k/2007-November/001771.html>, so
> before the above mentioned discussion.

That problem was a much easier issue with filldraw not updating the boundingbox to 
reflect the pen, and it was not related to the envelope tracing at all. 

AFAIR, I fixed only one minor issue with the envelope code, and that was
a case where one of the original pen knots was accidentally removed because
part of the cleanup code believed it was a degenerate knot introduced by its 
own simplification routine earlier (and that is why there is now an 'originator' field 
in each knot).

I have not touched any of the really serious bugs with pen tracing at all. The
problems are just too hard for me (well, I would know how to use a temporary 
bitmap and apply re-vectorisation using curve fitting, but that is not what we want).

Best wishes,
Taco