On Thu, 15 Jul 2021, Hans Hagen wrote:
> On 7/14/2021 4:43 PM, Gavin wrote:
> > Hello ConTeXters,
> >
> > I’d like to use the mp-geo Metapost package with ConTeXt to draw simple
> globes viewed from various directions. The package is here:
> >
> > https://melusine.eu.org/syracuse/poulecl/mp-geo/
> >
> > It looks like the last update was 2008 and I don’t read French, so I though
> my chances of getting anything to work were pretty small. However, I was
> pleasantly surprised that this MWE found the mp-geo package, the necessary
> Metapost files in the ConTeXt installation, and the data files.
> >
> > \starttext
> > \startMPcode
> > input mp-geo;
> > figure(-10u,-10u,10u,10u);
> > Mercator(3,48,30);
> > fin;
> > end
> > \stopMPcode
> > \stoptext
> >
> > While all of the files were found, it did not produce a globe. Instead I got
> an error complaining about an invalid character in the data files. This error
> is repeated for about 20 files (a small fraction of the total). I put the
> first error and its data file below. All the others are identical with
> different .dat files.
> >
> > Maybe it’s just an encoding mismatch or a hidden character I can easily
> delete or replace. On the other hand, maybe I shouldn't even be attempting
> this? 2008 is a long time ago in ConTeXt time. Feel free to tell me this
> project is crazy, but if you have an idea how I can make this work, I’d really
> appreciate it! It looks like a fun package.
> Looks interesting (I didn't know about it, also the surface stuff).
> Anyway, the message relates to scantokens not liking what gets read from
> a file, quite probably a missing file (I'll make it return a different
> message but still one needs to be aware of the fact that fiel reading in
> mp is kind of weird so it really expects a file).
Actually the data files are fairly simple:
no_of_points
<list of coordinates>
So, it would be much simpler to read and parse it via lua rather than
scantokens. Rest of the code simply determines a "view" of what to show. So, it
can be a good exercise in lua-MP interface.
Aditya
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