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@anntzer anntzer commented Apr 18, 2025

The next step after #29829 ("Rework mapping of dvi glyph indices to freetype indices.") in preparation for #29807 ("Support {lua,xe}tex as alternative usetex engine.").

luatex and xetex generate slightly different versions of dvi files (compared to plain tex and also between themselves) to give them the ability to refer to TrueType (OpenType) fonts installed system-wide. This patch implements parsing for these dialects, and adjusts the relevant classes in dvifont so that one can indeed represent these fonts and their metrics.


Minor API design point: The DviFont.path (cached) property can raise an exception if no type1 font is associated with the tex fontname. This should be rare (and not recoverable, i.e. we would fail to generate proper output in that case anyways), but it does feel a bit dirty to raise an exception in a property. I can switch that to a plain method, e.g. DviFont.get_path or DviFont.resolve_path, if desired (but then there would be a bit of asymmetry with the other (never-raising) properties DviFont.subfont and DviFont.effects). Not a very big deal, but just in case anyone has an opinion...

I decided in favor of resolve_path() (with manual caching), in particular because there is a future case (#20469 pk font support) where mapping the texname to an actual font file will even require on-the-fly generation of the font file (see mktex=pk option of kpsewhich, https://linux.die.net/man/1/kpsewhich).

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@anntzer anntzer force-pushed the luadviparse branch 2 times, most recently from af451c9 to 87e0ecf Compare April 18, 2025 09:28
@anntzer anntzer force-pushed the luadviparse branch 2 times, most recently from 149992b to 6a177bd Compare May 11, 2025 11:19
@QuLogic QuLogic moved this to Ready for Review in Font and text overhaul Jun 5, 2025
@anntzer anntzer added this to the v3.11.0 milestone Jul 10, 2025
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anntzer commented Jul 10, 2025

Milestoning to 3.11 because I think this is fairly self-contained, and is already something that mplcairo could benefit from, even before #29807 adds support in the builtin backends. But feel free to remilestone if it doesn't make it in the end.

@anntzer anntzer force-pushed the luadviparse branch 2 times, most recently from f8d6ee7 to b987e24 Compare July 31, 2025 08:07
A glyph in the dvi file.
The *x* and *y* attributes directly position the glyph. The *font*,
*glyph*, and *width* attributes are kept public for back-compatibility,
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What about the glyph and width fields? Are they used?

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I restored their documentation. There's not plan to deprecate them (they are useful anyways, and deprecating fields in a namedtuple is a bit annoying) so I removed the mention of backcompat.

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Not sure I see the docs back again?

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Oops, fixed now.

@timhoffm timhoffm merged commit 9b4233b into matplotlib:main Sep 3, 2025
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@github-project-automation github-project-automation bot moved this from Ready for Review to Done in Font and text overhaul Sep 3, 2025
@anntzer anntzer deleted the luadviparse branch September 4, 2025 06:54
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anntzer commented Sep 4, 2025

Thanks for the review :)

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