[metapost] problem with 'dvips mproof'

[Taco Hoekwater]

On 10/11/2010 02:36 PM, Stephan Hennig wrote:
> 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?

Yes.

> 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?

Partially. That whole paragraph refers to the old situation where only
0 and 1 existed. prologues=2 is good enough *assuming* the font is
already known to the postscript interpreter, otherwise 3 is needed.

Best wishes,
Taco