[metapost] bizarre interactions...

[Dan Luecking]

At 02:13 AM 4/7/2012, Karel wrote:
>Walt Burkhard napsal(a):
>>Hello.
>>I am trying to use the \mpattern  (my google mail program wants me 
>>to type only pattern!!)  in a very simple metapost program.   There 
>>seems to be strange things going on.  I have attached the metapost 
>>and tex programs here.
>>  The presence of the pattern seems to spoil metapost's ability to 
>> use tex properly.
>>Any ideas what is going on? or even better how to avoid this issue?
>
>I have compiled your metapost file and donot see any problem (mpost 1.212).
>Karel Horak

In my set-up (TeX Live, Windows 7, metapost 1.504) the
first and third figures show Courier text instead of
cmssdc10 and some characters misplaced. One assumes that
this is because mpattern redefines /fshow (a standard trick
for introducing PS commands for which Metapost doesn't have
an interface). The use of Courier is a Ghostscript default
for an unknown font. If I ask GSview to show me Ghostscript's
messages, I see many complaints of unknown fonts.

I also get error messages from "pdftex mpsproof ttt.1",
presumably because this command ultimately calls on
supp-pdf.tex to parse the file ttt.1 directly and that file
no longer contains standard metapost postscript.

It seems to me that I remember ConTeXt having a way to
permit patterns in metapost output, and that supp-pdf
was written to recognize those methods, but I don't know
any details.

I have often created pattern fills, but I do it by
writing a loop that draws some basic figure shifted to
enough places to cover the boundingbox of a closed curve,
then clipping the resulting picture to that curve.

Dan

Daniel H. Luecking
Department of Mathematical Sciences
Fayetteville, Arkansas
http://www-cs-faculty.stanford.edu/~knuth/iaq.html