[metapost] Metafont: editing CM source files (was: [OT]: Where to ask for help with metafont?)

[Rodolfo Medina]

Rodolfo Medina wrote:

> It seems that the old metafont mailing list: metafont at ens.fr is not active any
> more.


Karl Berry wrote:

>> That's a shame.  I guess I'll ask Michel, and maybe set one up on tug if
>> that seems like the way to go.


Rodolfo:

> Can anyone please suggest where to ask questions about metafont related
> matters?  Maybe the present one itself?


Karl:

>> Seems like the only alternative for now.  Or comp.text.tex.



Hans Hagen <pragma at wxs.nl> writes:

> just post questions to the metapost list; there is no need for a separate
> metafont list nowadays; if i knew how to unsubscribe the unmoderated mf list
> i'd already done it -)  



All right, thanks.

I wanted to edit cmr12.mf to see what happens.
So I copied the original file into a work directory, changed its name and ran
metafont on it:

 $ mf my-cmr12.mf
 $ gftopk my-cmr12.2602gf

. Then, in my-file.tex I put:

\font\myfont=my-cmr12

\myfont

Hallo

\vfill\eject\end

, and then I do:

 $ tex my-file

. Now, the changes I do in my-cmr12.mf seem to produce no effect at all in the
my-file.dvi output file.  For example, if I change the 12pt size into 50pt, in
dvi file the characters are always 12pt small.

Can anyone explain why?  What am I missing?
Please pardon the basicness of the question.

Thanks,
Rodolfo