One of the earliest issues with Libertinus Math was its original lack of support for calligraphic letters (#8). This was addressed in 5a5c7e0ecb930cbab8e9d39b13891f372d6f8be6 by copying the needed letters from XITS. This solved the original issue, but one problem remained open:
In mathematics, there are typically two styles of calligraphic letters in use: chancery and roundhand (aka \mathcal and \mathsfr). Unicode does currently not distinguish between these two styles, and Libertinus chose to use roundhand style. However, it was already mentioned in the original issue (https://github.com/alerque/libertinus/issues/8#issuecomment-295230287) that Unicode should make it possible to distinguish between the two styles at some point in the future.
This future will arrive with the upcoming Unicode 14. The exact date is still some time off,² but I’d already like to draw some attention to this issue. I think it would be nice if Libertinus Math were to provide both chancery letters and roundhand letters. I suspect that it makes the most sense to search for a suitable set of chancery letters in another (math) fonts (as was done with the roundhand letters).
One of the earliest issues with Libertinus Math was its original lack of support for calligraphic letters (#8). This was addressed in 5a5c7e0ecb930cbab8e9d39b13891f372d6f8be6 by copying the needed letters from XITS. This solved the original issue, but one problem remained open:
In mathematics, there are typically two styles of calligraphic letters in use: chancery and roundhand (aka
\mathcaland\mathsfr). Unicode does currently not distinguish between these two styles, and Libertinus chose to use roundhand style. However, it was already mentioned in the original issue (https://github.com/alerque/libertinus/issues/8#issuecomment-295230287) that Unicode should make it possible to distinguish between the two styles at some point in the future.This future will arrive with the upcoming Unicode 14. The exact date is still some time off,² but I’d already like to draw some attention to this issue. I think it would be nice if Libertinus Math were to provide both chancery letters and roundhand letters. I suspect that it makes the most sense to search for a suitable set of chancery letters in another (math) fonts (as was done with the roundhand letters).
¹ More details can be found at https://devblogs.microsoft.com/math-in-office/unicode-math-calligraphic-alphabets/ and https://www.unicode.org/L2/L2020/20275r-math-calligraphic.pdf. ² September 14