[metapost] Filling complex paths

[Hans Hagen]

On 10/17/2014 9:38 AM, Hans Hagen wrote:
> On 10/16/2014 11:44 PM, Tobias Columbus wrote:
>> Hi all,
>>
>> I am currently writing a piece of software that should spit out some
>> MetaPost
>> code. My input are the closed curves of a glyph and I want to produce
>> MetaPost
>> code that fills them according to Postscript rules. However, as
>> MetaPost cannot
>> handle non-contiguous closed paths, this task seems difficult at least.
>>
>> Note that the glyphs come from non-Postscript fonts, so that the MetaPost
>> "glyph" primitive does not work for me. I also tried "graphictext" as
>> described
>> in the Metafun manual but that turned out to be too inaccurate. I
>> traced the
>> inaccuracy back to "pstoedit", which is called for "graphictext".
>>
>> My attempt was to fiddle around with specials and
>> withprescript/withpostscript.  This attempt turned out to be nonsense as
>> addto always writes "stroke" or "fill" and my specials were ignored. I
>> could, of course, write the whole glyph with specials, but I would
>> prefer a cleaner solution.
>>
>> Has anybody some experience with this kind of problem? How difficult
>> would it be to add filling of non-contiguous paths to MetaPost?
>
> some of this unfilling is supported out of the box
>
> \startMPpage
>
> path p ; p := fullcircle scaled 10cm .. fullcircle scaled 5cm .. cycle ;
> fill p ; drawarrow p withcolor red ;
>
> currentpicture := currentpicture shifted (-11cm,0) ;
>
> path p ; p := fullcircle scaled 10cm .. reverse fullcircle scaled 5cm ..
> cycle ;
> fill p ; drawarrow p withcolor red ;
>
> \stopMPpage

btw, with -- it's a bit less fun

\startMPpage

path p ; p := fullcircle scaled 10cm -- fullcircle scaled 5cm -- cycle ;
fill p ; drawarrow p withcolor red ;

currentpicture := currentpicture shifted (-11cm,0) ;

path p ; p := fullcircle scaled 10cm -- reverse fullcircle scaled 5cm -- 
cycle ;
fill p ; drawarrow p withcolor red ;

\stopMPpage

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