Horizontally aligning text or symbols in a fraction

Question

I am using the code from egreg (a new command, xabove) from my previous question to typeset a "fraction" without the fraction bar.

In the following MWE, would there be a straightforward way to horizontally align the colons (:) in "A: 3.14" and "B: 6.28"? Or would I need to use a different definition of xabove?

\documentclass[oneside,11pt]{book}
\usepackage[semibold,tt=false]{libertine}
\usepackage{libertinust1math}
\usepackage[T1]{fontenc}
\usepackage[
  expansion = false ,
  tracking = smallcaps ,
  letterspace = 40 ,
  final
]{microtype}
\usepackage{booktabs}
% egreg's answer (https://tex.stackexchange.com/a/590218/15622)
\makeatletter
\DeclareRobustCommand{\xabove}[2]{{%
  \mathpalette\fix@genfrac{{#1}{#2}}%
}}
\newcommand{\fix@genfrac}[2]{\fix@@genfrac#1#2}
\newcommand{\fix@@genfrac}[3]{%
  \genfrac{}{}{\fix@@@genfrac{#1}}{}{#2}{#3}%
}
\newcommand{\fix@@@genfrac}[1]{%
  \ifx#1\displaystyle 0pt\else
  \ifx#1\textstyle -\fontdimen8\textfont2 \else
  \ifx#1\scriptstyle -\fontdimen8\scriptfont2 \else
  0pt % but doesn't really work :-(
  \fi\fi\fi
}
\makeatother
\begin{document}
$\xabove{\textit{A}:;3.14}{\textit{B}:;6.28}$
\end{document}

@egreg Since I thought the same thing, but obviously you preceded me :-), here is another shameful but working solution: $\xabove{\textit{\makebox[3mm]{A:}}\;3.14}{\textit{\makebox[3mm]{B:}}\;6.28}$ — Ivan, Mar 29 '21 at 17:00

score 4 · Answer 1 · answered Mar 29 '21 at 17:14

An aligned TABstack can do the job. Here I choose a (user-selectable) 2.5pt gap between rows of the stack which I believe fits and does not force a larger interline gap in the text.

\documentclass[oneside,11pt]{book}
\usepackage[semibold,tt=false]{libertine}
\usepackage{libertinust1math}
\usepackage[T1]{fontenc}
\usepackage[
  expansion = false ,
  tracking = smallcaps ,
  letterspace = 40 ,
  final
]{microtype}
\usepackage{booktabs}
\usepackage{tabstackengine,lipsum}
\TABstackMath
\TABstackMathstyle{\scriptstyle}
\begin{document}
\lipsum[1]
\alignstackanchor[2.5pt]{A:&;3.14}{B:&;6.28} % FOR S \stacktype
\lipsum[2]
\end{document}

score 3 · Answer 2 · answered Mar 29 '21 at 17:32

You can do it, but you should think whether this is really what you want.

\documentclass[oneside,10pt]{book}
\usepackage{amsmath,mathtools}
\usepackage[semibold,tt=false]{libertine}
\usepackage{libertinust1math}
\usepackage[T1]{fontenc}
\makeatletter
\DeclareRobustCommand{\xabove}[2]{{%
  \mathpalette\fix@genfrac{{#1}{#2}}%
}}
\newcommand{\fix@genfrac}[2]{\fix@@genfrac#1#2}
\newcommand{\fix@@genfrac}[3]{%
  \genfrac{}{}{\fix@@@genfrac{#1}}{}{#2}{#3}%
}
\newcommand{\fix@@@genfrac}[1]{%
  \ifx#1\displaystyle 0pt\else
  \ifx#1\textstyle -\fontdimen8\textfont2 \else
  \ifx#1\scriptstyle -\fontdimen8\scriptfont2 \else
  0pt % but doesn't really work :-(
  \fi\fi\fi
}
\newcommand{\labeledabove}[4]{%
  \xabove{\above@label{#1}{#3}{:};\hfill#2}{\above@label{#3}{#1}{:};\hfill#4}%
}
\newcommand{\above@label}[2]{\mathpalette\above@@label{{#1}{#2}}}
\newcommand{\above@@label}[2]{\above@@@label#1#2}
\newcommand{\above@@@label}[3]{%
  {\sbox\z@{\vbox{\ialign{$\m@th#1##\mkern-2mu$\hfil\cr#2\cr#3\cr}}}\makebox[\wd\z@][l]{$\m@th#1#2$}}
}
\makeatother
\begin{document}
$\displaystyle\frac{1}{2}\xabove{1}{2}$
$\textstyle\frac{1}{2}\xabove{1}{2}$
$\scriptstyle\frac{1}{2}\xabove{1}{2}$
%$\scriptscriptstyle\frac{1}{2}\xabove{1}{2}$
\bigskip
$\displaystyle\labeledabove{A}{3.14}{B}{6.28}\quad\xabove{1}{2}$
\medskip
$\labeledabove{A}{3.14}{B}{6.28}\quad\xabove{1}{2}$
\end{document}

score 3 · Accepted Answer · answered Mar 29 '21 at 22:24

Here is a straight-forward way via \phantom:

\documentclass{article}
\usepackage[semibold,tt=false]{libertine}
\usepackage{libertinust1math}
\usepackage[T1]{fontenc}
\usepackage{mathtools}
% egreg's answer (https://tex.stackexchange.com/a/590218/5764)
\makeatletter
\DeclareRobustCommand{\xabove}[2]{{%
  \mathpalette\fix@genfrac{{#1}{#2}}%
}}
\newcommand{\fix@genfrac}[2]{\fix@@genfrac#1#2}
\newcommand{\fix@@genfrac}[3]{%
  \genfrac{}{}{\fix@@@genfrac{#1}}{}{#2}{#3}%
}
\newcommand{\fix@@@genfrac}[1]{%
  \ifx#1\displaystyle 0pt\else
  \ifx#1\textstyle -\fontdimen8\textfont2 \else
  \ifx#1\scriptstyle -\fontdimen8\scriptfont2 \else
  0pt % but doesn't really work :-(
  \fi\fi\fi
}
\makeatother
\begin{document}
$\xabove{\textit{A}:;3.14}{\phantom{\textit{A}}\mathllap{\textit{B}}:;6.28}$
\end{document}

This works because A and B are the only two things that have differing widths in the top/bottom. So we place the wider/larger inside a \phantom to achieve the desired placement/position and then insert the other (narrower/smaller) component in via \mathllap (from mathtools).

Horizontally aligning text or symbols in a fraction

3 Answers3