Re: Fallback fonts in LuaTeX via 'luaotfload.add_fallback' (was "Fontsets")
On 12/07/2022 22:26, Juan Manuel Macías wrote:
Today I discovered that luaotfload included in v. 3.12 a new
experimental function, luaotfload.add_fallback, to be able to add a list
of fallback fonts to a LuaTeX document, at a low level.
...
\documentclass{article}
\usepackage{fontspec}
\directlua{
luaotfload.add_fallback ("fallbacktest",{
"oldstandard:mode=harf;script=grek;color=FF;",
"oldstandard:mode=harf;script=cyrl;color=FF;",
"freeserif:mode=harf;script=arab;color=FF;",
"freeserif:mode=harf;script=dev2;color=FF;",
})}
\setmainfont{latinmodernroman}[RawFeature={fallback=fallbacktest}]
...
The main drawback I've found to this (at least I don't know how to solve
it at the moment) is that the fallback feature cannot be added via
\defaultfontfeatures. That would avoid having to (re)define all the
main/sans/mono/math families.
I agree that defining fallbacks for each font family is inconvenient.
Defining font per script resembles specifying fonts per language in
babel configuration, however fallback should work without explicit
switching of language. I have seen that babel may determine language
from character code points, but I have not tried if it works reliable
and if it affects performance (as it does for fallback fonts).
Maybe I did not read the manual with enough attention, maybe I tried it
with too old version of LuaTeX, but I had a problem with Emoji.
Depending on font such symbols either broke compilation or did not
appear in PDF (accordingly to pdffonts font was embedded, text may be
copied, but PDF viewers displayed blank space).
https://list.orgmode.org/orgmode/scuirf$m7o$1...@ciao.gmane.io/
Maxim Nikulin. Re: org-mode export to (latex) PDF. Sat, 17 Jul 2021
19:35:57 +0700
Fallback fonts in LuaTeX via 'luaotfload.add_fallback' (was "Fontsets")
Today I discovered that luaotfload included in v. 3.12 a new
experimental function, luaotfload.add_fallback, to be able to add a list
of fallback fonts to a LuaTeX document, at a low level.
(More info on page 18 of the luaotfload manual, with some examples).
I've been experimenting a bit with this function. For example:
#+begin_src latex
\documentclass{article}
\usepackage{fontspec}
\directlua{
luaotfload.add_fallback ("fallbacktest",
{
"oldstandard:mode=harf;script=grek;color=FF;",
"oldstandard:mode=harf;script=cyrl;color=FF;",
"freeserif:mode=harf;script=arab;color=FF;",
"freeserif:mode=harf;script=dev2;color=FF;",
}
)
}
\setmainfont{latinmodernroman}[RawFeature={fallback=fallbacktest}]
\begin{document}
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Donec
hendrerit tempor tellus. Donec pretium posuere tellus.
Δαρείου καὶ Παρυσάτιδος γίγνονται παῖδες δύο, πρεσβύτερος μὲν
Ἀρταξέρξης, νεώτερος δὲ Κῦρος· ἐπεὶ δὲ ἠσθένει Δαρεῖος καὶ ὑπώπτευε
τελευτὴν τοῦ βίου, ἐβούλετο τὼ παῖδε ἀμφοτέρω παρεῖναι. ὁ μὲν οὖν
πρεσβύτερος παρὼν ἐτύγχανε· Κῦρον δὲ μεταπέμπεται ἀπὸ τῆς ἀρχῆς ἧς
αὐτὸν σατράπην ἐποίησε, καὶ στρατηγὸν δὲ αὐτὸν ἀπέδειξε πάντων ὅσοι ἐς
Καστωλοῦ πεδίον ἁθροίζονται.
Emacs написан на двух языках: C и Emacs Lisp (Elisp, диалект Лиспа).
При этом сам редактор является интерпретатором Elisp. По сути дела,
большая часть Emacs написана на языке Elisp, и её можно рассматривать
как расширение к основной программе. Пользователи могут сами создавать
части Emacs, от отдельных функций до новых основных режимов. При этом
можно переопределять любые Elisp-функции, в том числе и те, что
являются частью самого редактора, и модифицировать функциональность
Emacs, изменив соответствующим образом некоторые функции.
Native speakers of Arabic generally do not distinguish between Modern
Standard Arabic and Classical Arabic as separate languages; they refer
to both as al-ʻArabīyah al-Fuṣḥá (العربية الفصحى) meaning the pure
Arabic. They consider the two forms to be two registers of one
language. When the distinction is made, they are referred to as فصحى
العصر Fuṣḥá al-ʻAṣr (MSA) and فصحى التراث Fuṣḥá al-Turāth (CA)
respectively.
उदु ज्योतिरमृतं विश्वजन्यं विश्वानरः सविता देवो अश्रेत् ।\\
क्रत्वा देवानामजनिष्ट चक्षुराविरकर्भुवनं विश्वमुषाः ॥ १ ॥\\
प्र मे पन्था देवयाना अदृश्रन्नमर्धन्तो वसुभिरिष्कृतासः ।\\
अभूदु केतुरुषसः पुरस्तात्प्रतीच्यागादधि हर्म्येभ्यः ॥ २ ॥
\end{document}
#+end_src
The main drawback I've found to this (at least I don't know how to solve
it at the moment) is that the fallback feature cannot be added via
\defaultfontfeatures. That would avoid having to (re)define all the
main/sans/mono/math families.
Best regards,
Juan Manuel
Re: fontsets
Stefan Nobis writes:
> Hmmm... maybe add optional extra config/output option to the fontset,
> like so:
>
> ┌
> │ ;; Fonts
> │ ((myfonta . ((pdflatex . "etc.") (lualatex ...) (html ...) ...))
> │ (myfontb ...)
> │ ...)
> │ ;; Fontsets
> │ ((myfontset .
> │ ((sans . myfonta)
> │(serif . myfontb)
> │(mono . myfontc)
> │(extra . ((lualatex . "\\defaultfontfeatures{Scale=MatchLowercase}")
> │ (html "some CSS...")...))
> │...))
> │ ...)
> └
>
> This way it may be possible to build a fontset library of fonts that
> blend well together, including some necessary fine-tuning.
I think it's a good idea. And I definitely like Timothy's idea of
fontsets, but I still think that LuaLaTeX and XelaTeX should be unified
in some way.
Perhaps one or two default fontsets could be added.
It was commented in some previous message about the possibility of
checking if a font is present in the system. To add some extra
information, TeX live 2022 includes a lua script, luafindfont, which
runs luaotfload in the background. It is very useful because, in
addition to system fonts, it also returns results from TeX live fonts. I
use this script via helm, and I wrote this to extract a list of
candidates:
#+begin_src emacs-lisp
(defun build-luafindfont-candidates-list (candidate)
(interactive)
(let* ((query (shell-command-to-string (concat "luafindfont " candidate)))
(str (with-temp-buffer
(insert query)
(goto-char (point-min))
(let ((from
(save-excursion
(re-search-forward "1\\." nil t)
(beginning-of-line)
(point)))
(to
(save-excursion
(goto-char (point-max))
(point
(save-restriction
(narrow-to-region from to)
(buffer-string)
(str-clean (split-string
(with-temp-buffer
(insert str)
(replace "[[:digit:]]+\\.\s+" "")
(replace "\\(.+\\)\\(\\.otf\\|\\.ttf\\)\s+" "")
(replace "\s+" " -- ")
(buffer-string)) "\n" t)))
(setq luafindfont-list (mapcar 'identity
str-clean
#+end_src
On the other hand, fontspec includes the \IfFontExistsTF command.
According to the fontspec documentation:
--
\IfFontExistsTF{⟨font name⟩}{⟨true branch⟩}{⟨false branch⟩}
The conditional \IfFontExistsTF is provided to test whether the ⟨font name⟩
exists or
is loadable. If it is, the ⟨true branch⟩ code is executed; otherwise, the
⟨false branch⟩ code is.
This command can be slow since the engine may resort to scanning the filesystem
for a
missing font. Nonetheless, it has been a popular request for users who wish to
define ‘fallback
fonts’ for their documents for greater portability.
In this command, the syntax for the ⟨font name⟩ is a restricted/simplified
version of the
font loading syntax used for \fontspec and so on. Fonts to be loaded by
filename are detected
by the presence of an appropriate extension (.otf, etc.), and paths should be
included inline.
E.g.:
\IfFontExistsTF{cmr10}{T}{F}
\IfFontExistsTF{Times New Roman}{T}{F}
\IfFontExistsTF{texgyrepagella-regular.otf}{T}{F}
\IfFontExistsTF{/Users/will/Library/Fonts/CODE2000.TTF}{T}{F}
---
Best regards,
Juan Manuel
Re: fontsets
Juan Manuel Macías writes:
> [1] I have to add, by the way, that MatchLowercase is not always a
> panacea.
Hmmm... maybe add optional extra config/output option to the fontset,
like so:
┌
│ ;; Fonts
│ ((myfonta . ((pdflatex . "etc.") (lualatex ...) (html ...) ...))
│ (myfontb ...)
│ ...)
│ ;; Fontsets
│ ((myfontset .
│ ((sans . myfonta)
│(serif . myfontb)
│(mono . myfontc)
│(extra . ((lualatex . "\\defaultfontfeatures{Scale=MatchLowercase}")
│ (html "some CSS...")...))
│...))
│ ...)
└
This way it may be possible to build a fontset library of fonts that
blend well together, including some necessary fine-tuning.
--
Until the next mail...,
Stefan.
Re: fontsets
Hi, Timothy,
Timothy writes:
> Yep, so in my config’s implementation I have an alist of fontset names and
> individual fonts. For something part of org-mode itself, we’d probably want to
> add a format level to this, something like:
>
> ┌
> │ ((fontset-name .
> │ ((serif .
> │ ((pdflatex . "\\usepackage{myserif}")
> │ (lualatex . "etc.")
> │ (html . "and so on")))
> │(sans ...) ... ))
> │ (another-fontset ...) ...)
> └
>
> Actually, now that I think of it maybe it would be better to seperate out the
> fontsets and fots, e.g.
>
> ┌
> │ ;; Fonts
> │ ((myfonta . ((pdflatex . "etc.") (lualatex ...) (html ...) ...))
> │ (myfontb ...)
> │ ...)
> │ ;; Fontsets
> │ ((myfontset .
> │ ((sans . myfonta)
> │(serif . myfontb)
> │(mono . myfontc)
> │...))
> │ ...)
> └
>
>> In any case, I think it would also be nice if the user could add only
>> one family for roman, sans, mono or math, if he/she prefers it that way.
>> Something like:
>>
>> #+options: rmfont:Minion Pro
>
> Sure. There’s another bit of functionality in my config which I think is worth
> noting, you can add a -sans/-serif/-mono suffix to the fontset name to
> override
> the default body text font.
I see. I like your approach. And the idea of fontsets also seems very
productive. I suppose that a minimum configuration in fontspec
(Scale=MatchLowercase) should be ensured, in order to balance the
x-height when using fonts from different families in a single document[1].
The fact that all of this can also be "reusable" for other outputs such as
html, is a not insignificant plus! I definitely really like all of these
ideas and I don't think there is any contradiction with a balance
between those users who are content with minimal out-of-the-box font
configuration to be able to read non-latin characters, and those who
want more control over fontspec (font features, etc). And there are also
the users (me among them) who leave little or almost no space for Org to
write the preamble for us :-)
On the other hand, maybe (I think) it would be nice not to differentiate
between xelatex and lualatex, since at least at this level both engines
support the same fontspec settings.
[1] I have to add, by the way, that MatchLowercase is not always a
panacea. In many cases, and depending on the fonts, it may be better to
allow some contrast between families. Maybe it would be nice to add to
the documentation or to worg (at least for users who may be interested
in these topics) some basic recommendations for combining families (for
example, combining a bodoni with a bembo is usually a catastrophic
marriage :-).
Best regards,
Juan Manuel
Re: fontsets (was: [possible patch] Basic fontspec code for LuaLaTeX and XelaTeX (was "LaTeX export: when is it more useful..."))
Hi Juan,
> When you talk about fontset, I understand that you mean lists of
> families with their options that you have previously defined, is that
> right?
Yep, so in my config’s implementation I have an alist of fontset names and
individual fonts. For something part of org-mode itself, we’d probably want to
add a format level to this, something like:
┌
│ ((fontset-name .
│ ((serif .
│ ((pdflatex . "\\usepackage{myserif}")
│ (lualatex . "etc.")
│ (html . "and so on")))
│(sans ...) ... ))
│ (another-fontset ...) ...)
└
Actually, now that I think of it maybe it would be better to seperate out the
fontsets and fots, e.g.
┌
│ ;; Fonts
│ ((myfonta . ((pdflatex . "etc.") (lualatex ...) (html ...) ...))
│ (myfontb ...)
│ ...)
│ ;; Fontsets
│ ((myfontset .
│ ((sans . myfonta)
│(serif . myfontb)
│(mono . myfontc)
│...))
│ ...)
└
> In any case, I think it would also be nice if the user could add only
> one family for roman, sans, mono or math, if he/she prefers it that way.
> Something like:
>
> #+options: rmfont:Minion Pro
Sure. There’s another bit of functionality in my config which I think is worth
noting, you can add a -sans/-serif/-mono suffix to the fontset name to override
the default body text font.
All the best,
Timothy
