[metapost] problem with 'dvips mproof'

[Stephan Hennig]

Am 10.10.2010 02:52, schrieb Reinhard Kotucha:

> If you want to post-process the file with dvips, set prologues := 0
> (or not at all).  Then you'll see a comment line
>
> %*Font: cmr10 9.96265 9.96265 65:8003
>
> in the created PostScript file.  This line is evaluated by dvips and
> allows dvips to insert the fonts.  Its format is explained on page 29
> of the dvips manual.
>
> With prologues>  0 metapost creates (more or less) standalone
> PostScript files.  Standalone means that either the font is embedded
> or is included by the PS interpreter itself.
 >
 > [...]
>
> BTW, the prologues variable might be confusing because you have to
> remember what all the values are good for.  But it's probably helpful
> to know that Metapost was designed to support dvips in the first
> place,

Two questions to help me understand MetaPost-dvips interaction better:

1. Is my understanding correct, that the line

      %*Font: cmr10 9.96265 9.96265 65:8003

    is no standard PostScript (besides being a comment), but a
    convention MetaPost and dvips developers (Hobby & Rokicki)
    agreed upon for referring to TeX fonts back in time?


2. To quote from mpman as of MetaPost v0.641 (somehow that
    paragraph became deleted in mpman):

> Giving this internal variable a positive value causes causes output
> to be formatted as "structured PostScript" generated on the
> assumption that text comes from built-in PostScript fonts. This makes
> MetaPost output much more portable, but it has an important drawback:
> It generally does not work when you use TEX fonts, since programs
> that translate TEX output into PostScript need to make special
> provisions for TEX fonts in included 
gures and the standard
> PostScript structuring rules do not allow for this.

    The special provisions referred to is embedding encoding
    vectors into EPSF files (supported by setting prologues to 2
    since MetaPost v1.000).  True of false?

Best regards,
Stephan Hennig