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LaTeX: MathTeXEngine 0.5.0, Luxor version 3.5.0 #241

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cormullion opened this issue Jul 28, 2022 · 19 comments
Open

LaTeX: MathTeXEngine 0.5.0, Luxor version 3.5.0 #241

cormullion opened this issue Jul 28, 2022 · 19 comments

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@cormullion
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MathTeXEngine version 0.5 changed their LaTeX code, so please could Luxor-LaTeXers check and report any issues with Luxor 3.5.0? Thanks!

@cormullion cormullion changed the title LaTeX: MathTeXEngine 0.5.0 hello, Luxor version 3.5.0 LaTeX: MathTeXEngine 0.5.0, Luxor version 3.5.0 Jul 28, 2022
@davibarreira
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Ok, now I've found this issue. I'll try to check it during lunch. Have you already found any problems?

@cormullion
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I think the font selection code doesn’t find the NewComputerModern Italic easily, and defaults to Regular.

@Kolaru
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Kolaru commented Aug 1, 2022

Each TeXChar carry its own (FreeType) font, so it should be possible to add a binding in Cairo.jl that can access it direclty using https://www.cairographics.org/manual/cairo-FreeType-Fonts.html

Similarly, now that MathTeXEngine use glyph indices directly, you would need https://www.cairographics.org/manual/cairo-text.html#cairo-show-glyphs that doesn't seem to be exported by Cairo.jl either right now. CairoMakie call into the C library directly so it doesn't have those problems.

I could restore TeXChar.represented_char as a quick hotfix (i.e. a unicode char instead of a glyph index in a specific font), it would give the wrong glyph for greek letters, integral and sum, but should otherwise work nicely.

@cormullion
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Thanks. Ideally better font routines would be added to Cairo rather than to all the packages that depend on Cairo. I think more investigations are needed. Thanks for the excellent help, @Kolaru!

@cormullion
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Work that needs to be done to support MathTeXEngine v0.5.0 correctly might include:

  • integrating GeometryBasics.jl into Luxor *
  • integrating FreeType(Abstraction).jl into Luxor
  • adding call interfaces to Cairo.jl functions for showing glyphs, extents, fonts, etc.
  • writing code to read TeXChar glyph indices from fonts and draw glyphs

( Luxor.jl is showing its age - it predates GeometryBasics.jl by some years 😃; perhaps it should be rewritten to use JuliaGeometry packages...)

I think this is a lot of work, so for now LaTex text setting is less than perfect.

@davibarreira
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davibarreira commented Aug 4, 2022

Hey, @cormullion . Why does MathTeXEngine v0.5.0 requires such significant changes? I mean, more specifically, why GeometryBasics.jl?

@cormullion
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I was looking at Julius' work here - https://github.com/JuliaPlots/Makie.jl/pull/2139/files# - it seems to need stuff from FreeType and GeometryBasics. MTXE now references the font glyphs directly, by index, rather than by Unicode. I'm no expert here, though! :)

@davibarreira
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So, I took a look at the code to try to understand what was going on. Did the original fonts for the symbols change? In theory, the code I wrote for Luxor should work, as it get's the current font set by MathTeXEngine, and applies the fontface. Why doesn't it find the font anymore?

@cormullion
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The main thing I noticed (not being a Latex user) is that the italic fonts weren't found when the documentation job was run. I'm guessing that the use of FreeTypeAbstraction.jl finds/uses font names differently.

Version 0.4 of MTXE returned, for ^n:

(TeXChar 'n' [U+006E in cmmi10 - Regular], [10.481249809265137, 0.34492188692092896], 0.6)

Version 0.5 of MTXE returned, for ^n:

(TeXChar 'n' [index 79 in NewComputerModern - 10 Italic], [10.489200115203857, 0.3878999948501587], 0.6)

The Cairo Toy Api's text() function is happy to select a font with Luxor.fontface("cmmi10"), but I'm not sure if it's happy with "NewComputerModern - 10 Italic" - but it would probably work OK if it received Luxor.fontface("NewCM10-Italic") though.

Perhaps we could use Luxor.settext and Luxor.setfont for all glyphs (not just the few you added), and work out how to select the fonts via setfont given strings like "NewComputerModern - 10 Italic".

The other issue is the use of glyph indices rather than represented_char -> Unicode. Code for this is probably already written somewhere (in MTXE and/or Makie). I don't know how I would do it other than by adding dependencies for FreeType and scanning the fonts for the indices.

@Kolaru
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Kolaru commented Aug 8, 2022

Did the original fonts for the symbols change?

Yes, I switch from the Computer Modern family (non unicode, a bunch of fonts for math symbols, weird glyph info in the font) to the New Computer Modern family (unicode, all symbols in a single font, but alternate glyph for some math symbols, requiring the glyph index business).

I don't think that GeometryBasics should be needed. The point type used for the position are from there, but that a mere detail I believe.

The other issue is the use of glyph indices rather than represented_char -> Unicode. Code for this is probably already written somewhere (in MTXE and/or Makie)

https://github.com/JuliaPlots/Makie.jl/pull/2139/files#diff-4c2354928757044a6b2d42b25e45db4aa14412f8a0367d3c28db496d62f6b64dR458-R463

This is it in the compat PR in Makie. I think the simpler way is probably to add a similar function to Cairo.jl and then use it there. I am not familiar with ccall so I can't promise anything, but I'll have a look next week-end if no one beats me to it.

@cormullion
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cormullion commented Sep 19, 2022

If anyone has some spare time, please check the current master - I've tried to update it to find the fonts. Haven't yet addressed the glyph indices though...

I think it works on MacOS, but can't test it on other platforms...

@davibarreira
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I was not able to figure it out :(

@cormullion
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Thanks for looking anyway, @davibarreira ! It's difficult to get the right fonts on all platforms, and I'm seeing a strange vertical misalignment (eg i and π) which I can't currently explain. Also I broke the rotation... :(

Screenshot 2022-09-25 at 08 40 12

@Kolaru
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Kolaru commented Oct 2, 2022

Can you share the code snippet to produce the image ? That way I'll be able to do quicker tests :)

@cormullion
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cormullion commented Oct 2, 2022

it's at http://juliagraphics.github.io/Luxor.jl/dev/howto/text/#Writing-LaTeX - my last attempt is on Luxor master...

@Kolaru
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Kolaru commented Oct 3, 2022

I made some progress in #244, but some stuff are still unclear.

@cormullion
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That's great! Will follow the Cairo PR with great interest!

@RaulDurand
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Thanks for looking anyway, @davibarreira ! It's difficult to get the right fonts on all platforms, and I'm seeing a strange vertical misalignment (eg i and π) which I can't currently explain. Also I broke the rotation... :(

Screenshot 2022-09-25 at 08 40 12

How can I get variables written in italics as LaTeX? Currently the snipped produces non italics text.

@stale stale bot added the wontfix label Mar 17, 2024
@JuliaGraphics JuliaGraphics deleted a comment from stale bot Mar 18, 2024
@rben01
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rben01 commented Jul 31, 2024

How can I get variables written in italics as LaTeX? Currently the snipped produces non italics text.

Same, I get this:

plot_4

Are the font files swapped? Should math be non-math and vice versa?

707CFF14-94B5-43F1-AD87-A37503002D32

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