[metapost] bullet placement: document mpgraph.pdf

[Dan Luecking]

At 05:53 AM 6/9/2012, you wrote:
>Hi,
>     I am looking at the document mpgraph.pdf:
>
>http://www.tug.org/docs/metapost/mpgraph.pdf
>
>and on page 3 it is shown how to just have bullets instead of lines 
>in a graph. In particular, for proper placement of the bullets at 
>the coordinates centre the following command is given:
>
>def MPbullet =
>btex \lower\fontdimen22\cmsy \hbox to 0pt{\hss\cmsy\char15\hss} etex
>enddef;

This is an error in mpgraph.pdf. Replace \cmsy with \tensy
in both occurances. Make sure plain tex is used to make the
labels. For smaller bullets, you can use \sevensy or \fivesy.

>However this is not working. I have the lates TexLive and Metapost 
>1.504. Here is the error message:

Mpost by default does not provide much information on problems
with TeX labels. You might want to give it the --debug option:
   mpost --debug  plot.mp
This leaves behind the temporary tex-related files and you
can find (as I did) from the .log file, that \cmsy is undefined.

Note: When reporting problems, you should include in your email
a short (but complete) file that gives you the problem. The file
that works for me is:
% plot.mp
input graph;
def MPbullet =
   btex \lower\fontdimen22\tensy \hbox to 0pt{\hss\tensy\char15\hss} etex
enddef;
beginfig(1);
   draw begingraph(3in,2in);
     gdraw "agepop91.d" plot MPbullet;
   endgraph;
endfig;
end
% end of plot.mp

You also need to run mpost in a directory that contains the
data file agepop91.d. Oddly enough, I didn't get any complaints
from mpost about the missing file before I did that.

>... If you don't know why I had trouble,
>try running it manually through MPtoTeX, TeX, and DVItoMP

This part of mpost's help message has been somewhat misleading
for a while now. There is no program MPtoTeX anymore (at least
not in either TeX Live 2011 or 2012). The --debug option,
followed by an examination of the .log files, is the only way
I know of to see where the trouble lies.

Also DVItoMP does not exist as a separate program (again, at
least not in TeX Live).

Dan


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