How specify by Unicode number a particular character from another font (XeLaTeX)?

Question

The following defines commands \cmark and \xmarkto produce the Unicode characters with codes U+2718 and U+2714, respectively.

Question:

Is there some simpler, or alternative, way that the following to specify an individual character, from a different font than the main one in use — when only one or two characters from that font are going to be used?

% !TeX program =xelatexmk
\documentclass{article}
\usepackage{fontspec}
\usepackage{unicode-math}
\setmainfont{TeX Gyre Termes}
\setmathfont{TeX Gyre Termes Math}

% How  create command for character that has Unicode U+2718?
\newfontfamily{\xmarkfont}{LibertinusMath-Regular.otf}
\newcommand{\xmark}{\xmarkfont\char"2718}
\newfontfamily{\cmarkfont}{TeX Gyre Pagella Math}
\newcommand{\cmark}{\xmarkfont\char"2714}

\begin{document}
\begin{tabular}{lc}
Wrong & \xmark\\
Right & \cmark
\end{tabular}

\end{document}

Related: How find out name of ballot x mark in a unicode font with XeLaTeX?

Answer 1

You would really want to change the font inside a group, so the font change doesn’t bleed through to the text after it. So,

\newcommand{\xmark}{{\xmarkfont\char"2718}}

You would define \xmarkfont as you did in your MWE, to a font that has it, probably scaled with Scale=MatchUppercase.

In math mode with unicode-math, you can set the font for a specific math character with the range= option of \setmathfont.

You can use newunicodechar to set a character active, which allows you to paste it into your source, e.g.

\usepackage{newunicodechar}
\newunicodechar{^^^^2718}{\xmark}

This lets you type either \xmark, ઞ, or ^^^^2718 and have it just work.

In XeLaTeX, you can theoretically use ucharclasses to set the font for all dingbats, or any other Unicode block. As of July 2020, however, this package is broken and apparently unmaintained.

If you want to use the character from the current font if and only if the font has it, and fall back if and only if it does not, you would define the \xmark command as a conditional with \iffontchar.

In XeTEX, it is possible, but complicated, to insert commands (such as \begingroup\symbolfont and \endgroup) around a particular group of characters with \XeTeXinterchartoks. This lets you type them in and select the font correctly without explicit markup, and is what ucharclasses is supposed to be doing.