Kerning – How to Allow Line Breaking Without Affecting Kerning

ellipsiskerningline-breaking

I'm trying to get LaTeX to allow a line break after an ellipsis. The problem is that, when I type \allowbreak after \ldots, the kerning between the ellipsis and the next immediate character is messed up. In the MWE below, I have shown many pairs of the kerning between an ellipsis and the next immediate character with and without a line break after the ellipsis. As you can see, adding \allowbreak results in unkerned letterspacing. I want to automatically allow line breaking after an ellipsis without affecting the kerning.

Edit: The kerning is also messed up with the follwing fonts, which I just tested: Verdana Pro, Noto Serif, Roboto Serif, Source Serif Pro

\documentclass{article}
\raggedright
\usepackage{fontspec}
\setmainfont{Source Serif 4}[%Available for free on Google Fonts.
    Kerning=On%
]
\begin{document}
text\ldots{}apple\\
text\ldots{}\allowbreak{}apple\\

text\ldots{}candy\\
text\ldots{}\allowbreak{}candy\\

text\ldots{}banana\\
text\ldots{}\allowbreak{}banana\\

text\ldots{}doughnut\\
text\ldots{}\allowbreak{}doughnut\\

text\ldots{}eggplant\\
text\ldots{}\allowbreak{}eggplant\\

text\ldots{}fish\\
text\ldots{}\allowbreak{}fish\\

text\ldots{}grape\\
text\ldots{}\allowbreak{}grape\\

text\ldots{}henry\\
text\ldots{}\allowbreak{}henry\\

text\ldots{}salmon\\
text\ldots{}\allowbreak{}salmon\\

text\ldots{}tenth\\
text\ldots{}\allowbreak{}tenth\\

text\ldots{}ultra\\
text\ldots{}\allowbreak{}ultra\\

text\ldots{}violet\\
text\ldots{}\allowbreak{}violet\\

text\ldots{}water\\
text\ldots{}\allowbreak{}water\\

text\ldots{}xbox\\
text\ldots{}\allowbreak{}xbox\\

text\ldots{}yellow\\
text\ldots{}\allowbreak{}yellow\\

text\ldots{}zodiac\\
text\ldots{}\allowbreak{}zodiac\\
\end{document}

Best Answer

I don't think that I ever used the ellipsis before a word without a space, but if you really have that you can try \discretionary (I compiled with lualatex):

\documentclass{article}
\raggedright
\usepackage{fontspec}
\setmainfont{Noto Serif}[% replaced
    Kerning=On%
]

\begin{document}
text\ldots{}yellow\\
text\ldots{}\allowbreak{}yellow\\
text\ldots{}\discretionary{}{}{}yellow

\bigskip
\parbox{2mm}
{%
text\ldots{}yellow\\
text\ldots{}\allowbreak{}yellow\\
text\ldots{}\discretionary{}{}{}yellow
}
\end{document}

Related Solutions

Math Mode – Prevent Line Breaking in Inline Math with Flexible Spacing

I would say

\newcommand{\x}[1]{%
  {}$% get out of math
  \kern-2\mathsurround % in case it's non zero
  $% reenter math
  \binoppenalty10000 \relpenalty10000 #1% typeset the subformula
  {}$% get out of math
  \kern-2\mathsurround % in case it's non zero
  $% reenter math for the rest of the formula
}

TeX breaks formulas only after binary operators or relation symbols, the desirability of such breaks is measured by the two mentioned parameters. However the values used the penalties are those valid at the end of the formula, so simply enclosing #1 in \begingroup...\endgroup and setting the values wouldn't do anything.

Of course this can work only if used in suitable places of the formula, for example $a+\x{b+c}$ would have the right spacing after the first + (because of the empty subformula); the last empty subformula does nothing.

My opinion is still that bad breaks must be solved with suitably placed \nobreak commands.

Some examples:

\documentclass[a4paper,draft]{book}

\newcommand{\x}[1]{{}$\kern-2\mathsurround${}
  \binoppenalty10000 \relpenalty10000 #1{}$\kern-2\mathsurround${}}
\begin{document}
\parbox{5cm}{

A formula \(a+\x{c+d}\)\break showing that spaces are right

A new formula \(a+\x{c+d}\) showing that spaces are right

A brand new formula x \(a+\x{c+d}\) showing that spaces are right

A brand new formula xx \(a+\x{c+d}\) showing that spaces are right

A brand new formula xxx \(a+\x{c+d}\) showing that spaces are right

A brand new formula xxxx \(a+\x{c+d}\) showing that spaces are right

Another brand new formula \(a+\x{c+d}\) showing that spaces are right

Right: $\sin(\x{a+b})$

Wrong: $\sin\x{(a+b)}$


\mathsurround=30pt
A formula xxxxxxx \(a+\x{c+d}\) showing mathsurround

A formula xxxxxxx \(a+c+d\) showing mathsurround
}
\end{document}

Addition about usage
The \x macro (possibly with a more descriptive name) should be used in specific places. Its contents must

(1) start with an ordinary symbol or be preceded by an ordinary symbol;
(2) end with an ordinary symbol or be followed by one.

It doesn't support the style declarations \displaystyle, \textstyle, \scriptstyle, or \scriptscriptstyle; it may make sense to carry a \displaystyle declaration, this might be done with a *-variant.

It doesn't support \left or \right: it's not allowed something like

$...\left(\x{a+b}\right)...$

but this is not a problem, as no formula can be split at relation or operation symbols between \left and \right and the spaces around these symbols never participates to stretching or shrinking.

Line Breaking – Allow Line Break Without Inserting a Dash in LaTeX

You could insert \allowbreak whereever a break without hyphen shall be allowed, such as

long\allowbreak word

Best Answer

Related Solutions

Math Mode – Prevent Line Breaking in Inline Math with Flexible Spacing

Line Breaking – Allow Line Break Without Inserting a Dash in LaTeX

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