[metapost] format.mp and mptopdf

[Stephan Hennig]

Taco Hoekwater schrieb:

> I think you misinterpreted the mptopdf command. It does not
> (normally) run mpost for you, you have to do that before you
> call mptopdf.^

Yes, I read this before somewhere, but I have to admit I've never
understood the mechanism with mptopdf in detail. Is there some
documentation about which files are generated at which intermediate
step, where and why? I've seen some .mpx, .mpo, mptrace.tmp or texput
files and I know some more temporary files are stored somewhere else.
But who is who?


> mptopdf then converts the output file (formaterr.1) into
> formaterr-1.pdf

Isn't the name misleading? Anyway, the example was derived from a
MetaPlot file that compiles fine with mpost but then mptopdf refuses to
generate a pdf file from the output. It only complains about the
equations from format.mp and doing the changes described above solves
the problem. I'll try to prepare a new example later.


>> PS: Shouldn't the output of the example below show a dot? Adding
>> 'withpen pencircle scaled 2bp' does so.
>
> So does using drawdot instead of draw, or a 'pickup pen' command
> before the draw.

I did check mpman.pdf for all occurrences of "dot" before asking this.
Drawdot isn't documented in the manual.


> You are essentially drawin a one-node path without
> a pen, so nothing is output (well, officially, one device pixel should
> be drawn if you would have used a PostSCript interpreter, but that
> is nearly invisible). There is no default pen in MetaPost.

Thanks for the explanation! But why does

beginfig(1);
  draw origin--(100,100);
endfig;
end

draw a line when there is no default pen? Sorry for asking basic
questions here, but I am a bit irritated.

Regards,
Stephan Hennig