[NTG-context] Re: Working with layer sets with Metapost

[Mikael Sundqvist <mickep@gmail.com>]

Hi

On Thu, Feb 15, 2024 at 1:03 AM Emanuel Han via ntg-context
<ntg-context@ntg.nl> wrote:
>
> Dear list,
>
> the attached .tex file is the minimal working example we discussed today in the online meeting.
>
> I realized that the approach of looping through k of p[k] is not fitting my needs, because it's not flexible enough.
>
> I need another approach, one which works with layer sets.
>
> I would stop using p as an array, because with the layer sets approach we don't have a fixed order of the layers.
>
> So the definition of the layers would be something like
>
>     picture layerA;
>     layerA:=image(
>     label("Word 1", z1);
>     );
>
>     picture layerW;
>     layerW:=image(
>     label("Mot 2", z2);
>     );
>
>     picture layerM;
>     layerM:=image(
>     label("Parola 3", z3);
>     );
>
>     picture layerC;
>     layerC:=image(
>     label("Wort 4", z3+z1);
>     );
>
>     picture layerY;
>     layerY:=image(
>     label("Nummer 5", z2+z3);
>     );
>
>     picture layerU;
>     layerU:=image(
>     label("number 6", z2+z1);
>     );
>
> After that, I would define layer sets and layer subsets. This will be done manually for each layer set and each layer subset.
> I don't know the proper syntax to do that. Let's assume we could use a variable type called "myset".
>
> myset layersubsetGamma;
> layersubsetGamma:={layerU,layerM};
>
> In my logic, the layers will be drawn in the order of their appearance within the {}. In the example, drawn content of layerM might cover drawn content of layerU.
>
> Contrary to a layer subset, each layer set will result in a PDF page, and thus the layer sets are related to each other by an inner order. That's why I would use an array variable here with [].
>
> I don't know how to append a set. In the following example, I assumed there would be a function myappend(<initial set>, <the things what the initial set should be appended with>)
>
> myset layerset[];
> layerset1 := {layerW,layerA};
> layerset2 := myappend{layerset1, layerY};
> layerset3 := myappend{layerset2, layersubsetGamma};
> layerset4 := myappend{layerset2, layerU};
> layerset5 := myappend{layerset4, layersubsetGamma};
>
> Finally, I would need each layerset[k] typeset on its own pdf page. And of course on each page k, only the layers which appear in the definition of the layerset[k] should be drawn on top of each other in the order as they appear in that definition.
>
> I'm very curious to hear your suggestions.
>

Not beautiful, perhaps, but maybe something like this could work? I
think there is no way out of doing some manual work to tell what you
want included on each page.

\startuseMPgraphic{base}
z1 = origin ;
z2 = (10,50) ;
z3 = (40,30) ;

picture layerA;
layerA:=image(
label("Word 1", z1);
);

picture layerW;
layerW:=image(
label("Mot 2", z2);
);

picture layerM;
layerM:=image(
label("Parola 3", z3);
);

picture layerC;
layerC:=image(
label("Wort 4", z3+z1);
);

picture layerY;
layerY:=image(
label("Nummer 5", z2+z3);
);

picture layerU;
layerU:=image(
label("number 6", z2+z1);
);
\stopuseMPgraphic

\startuseMPgraphic{Gamma}
draw layerU ;
draw layerM ;
\stopuseMPgraphic

\startuseMPgraphic{layerset1}
\includeMPgraphic{base}
draw layerW ;
draw layerA ;
\stopuseMPgraphic

\startuseMPgraphic{layerset2}
\includeMPgraphic{layerset1} ;
draw layerY ;
\stopuseMPgraphic

\startuseMPgraphic{layerset3}
\includeMPgraphic{layerset2} ;
\includeMPgraphic{Gamma} ;
\stopuseMPgraphic


\startuseMPgraphic{layerset4}
\includeMPgraphic{layerset2} ;
draw layerU ;
\stopuseMPgraphic

\startuseMPgraphic{layerset5}
\includeMPgraphic{layerset4} ;
\includeMPgraphic{Gamma} ;
\stopuseMPgraphic

\starttext

\startTEXpage[offset=1DK]
\useMPgraphic{layerset1}
\stopTEXpage

\startTEXpage[offset=1DK]
\useMPgraphic{layerset2}
\stopTEXpage

\startTEXpage[offset=1DK]
\useMPgraphic{layerset3}
\stopTEXpage

\startTEXpage[offset=1DK]
\useMPgraphic{layerset4}
\stopTEXpage

\startTEXpage[offset=1DK]
\useMPgraphic{layerset5}
\stopTEXpage

\stoptext

/Mikael
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl
webpage  : https://www.pragma-ade.nl / https://context.aanhet.net (mirror)
archive  : https://github.com/contextgarden/context
wiki     : https://wiki.contextgarden.net
___________________________________________________________________________________