Calligraphic math font in LibreOffice Math

walyso · August 21, 2025, 11:58pm

I use the Mathematical Alphanumeric Symbols block (U+1D400–U+1D7FF), but most of the important letters are in the Letterlike Symbols block (U+2100–U+214F). The two blocks look different on my system, except under weird scenarios. Also I think some of them look different on various systems.
Here are the important Letterlike Symbols characters under different scenarios. A preceding 𝒫 (U+1D4AB, from the Mathematical Alphanumeric Symbols block) seems to cause unexpected behavior in the third and fourth lines that ironically makes symbols look like the Mathematical Alphanumeric Symbols block, just as I want.

"X X" "X X ℇ ℊ ℋ ℌ ℍ ℎ ℏ ℐ ℒ ℓ ℔ ℕ ℘ ℙ ℚ ℛ ℜ ℝ ℤ ℬ ℭ ℰ ℱ ℳ ℴ ℵ ℶ ℷ ℼ ℽ ℾ ℿ ⅀ ⅅ ⅆ ⅇ ⅈ ⅉ X X"newline
"X X" "X X ℇ ℊ ℋ ℌ ℍ ℎ ℏ ℐ ℒ ℓ ℔ ℕ ℘ ℙ ℚ ℛ ℜ ℝ ℤ ℬ ℭ ℰ ℱ ℳ ℴ ℵ ℶ ℷ ℼ ℽ ℾ ℿ ⅀ ⅅ ⅆ ⅇ ⅈ ⅉ X 𝒫"newline
"X 𝒫" "X X ℇ ℊ ℋ ℌ ℍ ℎ ℏ ℐ ℒ ℓ ℔ ℕ ℘ ℙ ℚ ℛ ℜ ℝ ℤ ℬ ℭ ℰ ℱ ℳ ℴ ℵ ℶ ℷ ℼ ℽ ℾ ℿ ⅀ ⅅ ⅆ ⅇ ⅈ ⅉ X X"newline
"X X" "𝒫 X ℇ ℊ ℋ ℌ ℍ ℎ ℏ ℐ ℒ ℓ ℔ ℕ ℘ ℙ ℚ ℛ ℜ ℝ ℤ ℬ ℭ ℰ ℱ ℳ ℴ ℵ ℶ ℷ ℼ ℽ ℾ ℿ ⅀ ⅅ ⅆ ⅇ ⅈ ⅉ X X"newline

The look stays with the fourth line looking different when exiting the Math editor.
The third and fourth lines look different from the first and second lines here in the forum editor too. At least on my end.
Any recommendations? Maybe I should switch to using fonts, but I don’t know how.
OS Windows 7. LO 7.6.4.1 (x86). Save format odt
47.odt (20.1 KB)

ajlittoz · August 22, 2025, 10:06am

Here Fedora 42 with KDE Plasma desktop, LO 25.2.5.2

When I open your sample document, the frame displaying your “formula” contains a clipped version of it: though the frame has no overriding manual settings, its width is 17.32 cm which clips roughly after the double-struck lowercase pi. The As character frame should auto-size to the width of the rendered formula.

The fourth line appears to be displayed in another font face.

If I remove the double quotes, font face reverts from serif to sans variant. Similarly, when erasing U+1d4ab at start of line-4 string.

From experiment, it looks like the issue has a mix of problems, probably related to the lag in Math development:

first cause may be the absence of U+1d4ab from sans fonts (at least from Liberation Sans)
from the Wikipedia article, managing the block is a complicated task, subblock for the glyph requesting a specific variant (bold, outline, script, …)
It is probable that the glyph is allocated as a pointer (indirect access) to some shape already present in the font or another file (hence font substitution occurs)
if font face is forced through command font Sans "…", correct rendering occurs
you are using a long string which probably calls for a homogeneous rendering (the same face is used for all characters in the string)
Removing the quotes reverts to individual rendering of independent symbols.
the font renderer is possibly confused by the characters belonging in the SMP (Unicode plane 01) and badly interprets U+1d4ab in first position as a variation selector – which anyway does not work in LO (see tdf#150398)

I had not the patience to press Alt+X after all your characters to check which belong in the BMP, which in the SMP. You seem to hint you only inserted U+1d4ab from the SMP. And it seems to impact rendering in Writer only when it is in first position in a string (rendering in the Math sub-window at bottom is affected, no matter the position as is shown in lines 3 and 4).

I recommend you submit a bug but try to craft a simpler formula examplifying the issue. At this stage, I suspect bad management of Mathematical Alphanumeric Symbols block. So try to see if this happens with other glyphs in the block.

walyso · August 22, 2025, 5:41pm

I mostly didn’t understand you, but here is my try to see if this happens with other glyphs in the block. It turns out that it also happens in Writer. I’m going to stick with calligraphic uppercase latin for simplicity.

49.odt (20.1 KB)
I would like to be able to write the characters BEFHILMR in BMP like the characters ACDGJKNOPQSTUVWXYZ in SMP in Math. font Sans "..." didn’t affect BMP nor SMP characters on my system.

Regina · August 22, 2025, 1:53pm

The default font for text is set in Math module Format > Fonts. Click on Modify and select item Text. As Math equations are OLE-Objects, this is a per object setting. However, the settings are remembered to be used for new equations. But I think you do not want text but symbols.

When you work in the Math module directly, then you can customize a toolbar to contain the “Special character” dialog that you know already from Writer. You can use it to insert such symbols without being a text.

In case LibreOffice does not find a suitable font automatically, you can specify fonts explicitly in Custom Fonts in the lower part of the Fonts dialog and force its use with the tags font serif, font sans and font fixed, respectively.

For mathematical special characters you can use “STIX Two Text”. Download for example from https://fonts.google.com/specimen/STIX+Two+Text. Read more about STIX fonts in STIX Fonts project - Wikipedia and https://www.stixfonts.org/.

walyso · August 22, 2025, 6:11pm

Specifying fonts in Custom Fonts and forcing their use with those tags works, but then I don’t have any fonts that look like these symbols (preferably the black ones):

48.odt (18.5 KB)
When installed, does “STIX Two Text” appear in LO as a family of fonts like “STIX Mathematical Script”, “STIX Fraktur” and “STIX Double Struck” or something like that? I searched the links, but I don’t get how does it work.

Regina · August 22, 2025, 7:23pm

LibreOffice can only handle Regular, Italic, Bold and Bold Italic as one family. All other font styles will appear as own font in the drop-down lists in LibreOffice. For STIX Two Text that means, that the contained styles Medium and SemiBold will appear as “STIX Two Text Medium” and “STIX Two Text SemiBold”.

If you need all of such characters, not only those typically used, then install “STIX Two Math”. It covers the Unicode range “Mathematical Alphanumeric Symbols”. https://www.unicode.org/charts/PDF/U1D400.pdf. You can download the font from stixfonts/zipfiles at master · stipub/stixfonts · GitHub, take STIX2_13-all.zip, for example.