[Tex/LaTex] How to typeset a loudspeaker icon

symbols

I would like to include a loudspeaker icon, for instance by defining my own command \myloudspeaker:

I looked at Detexify and the Comprehensive LaTeX symbol list.

Best Answer

fontawesome provides a number of options:

\documentclass{article}

\usepackage{fontawesome}

\setlength{\parindent}{0pt}

\begin{document}

\faBullhorn \quad \verb|\faBullhorn| \\
\faVolumeOff \quad \verb|\faVolumeOff| \\
\faVolumeDown \quad \verb|\faVolumeDown| \\
\faVolumeUp \quad \verb|\faVolumeUp|

\end{document}

You're probably after \faVolumeUp.

Example for `siunitx` and pdfLaTeX

If lualatex or pdflatex cannot be used, then the symbol can be included as graphics. The graphics is generated by:

% franc.tex
\nofiles
\documentclass{article}
\usepackage{fontspec}
\begin{document}
\fontspec{FreeSerif.otf}
^^^^20a3
\end{document}

It is compiled via:

$ lualatex franc
$ pdfcrop franc

Then franc-crop.pdf can be used as image for pdfLaTeX:

\documentclass{article}
\usepackage{graphicx}
\usepackage{siunitx}
\DeclareRobustCommand*{\myfranc}{\includegraphics[scale=.1]{franc}}
\DeclareSIUnit{\franc}{\myfranc}

\begin{document}
\SI{123.45}{\franc}
\end{document}

If you are using lualatex or xelatex, then the font can be used directly, e.g.:

\DeclareRobustCommand*{\myfranc}{%
  \begingroup
    \fontspec{FreeSerif.otf}%
    ^^^^20a3%
  \endgroup
}

[Tex/LaTex] How to typeset the house of an algebraic number

There are some issues to consider:

Line width

The standard line width in TeX is 0.4pt, it is hardcoded in TeX as 26214sp.
\overline uses a different line width. It is taken from font parameter 8 of math font family 3 in TeX.

The standard math fonts (Computer Modern) are using 0.39998pt in all font sizes. But it is scalable in other fonts, e.g. package mathptmx with 10pt as class option:
- 0.3999pt in \textfont (\textstyle/\displaystyle)
- 0.29591pt in \scriptfont (\scriptstyle)
- 0.23993pt in \scriptscriptfont (\scriptscriptstyle)

`\overline`

TeX constructs a \overline{...} the following way with θ as line width (pseudo code):
```
\vbox{
  \kern θ
  \hrule height θ
  \kern 3*θ
  \hbox{$...$}
}
```
Especially there is white space above the rule. This is useful, if the overlined symbol is put in the denominator of a fraction, for instance.
TeX uses cramped math style for the math expression of \overline. This means, the superscripts are moved down a little, for a better visual appearance.

Thus \overline looks like a good choice for the "house" symbols. However, the vertical lines should use the same line width as used by \overline.

Spacings

TeX inserts 3 * θ (θ = line width of \overline) between the formula and the line in \overline. This cannot be easily changed without loosing cramped style. (AFAIK only LuaTeX can set cramped style explicitly.)
Extra space is added above the line in \overline, see above.
Usually symbols have side bearings, space at the left and right side of the symbol. The exact amount is usually not available in TeX. The example uses 2 * θ as horizontal space between the vertical lines and the formula. Also a horizontal space 1.5 * θ is put outside the vertical lines. Some kind of side bearings of the new symbol to avoid touching of housed math expressions.
Since the OP wants longer lines (see comment), the example adds 2 * θ as additional depth. (3 * θ seems too large, because there is not a underline that needs some distance from the formula.)

The full example also takes into account the different math styles, thus macro \house respects the current math sizes.

\documentclass{article}
\usepackage{mathptmx}

\makeatletter
\newcommand*{\house}[1]{%
  \mathord{%
    \mathpalette\@house{#1}%
  }%
}
\newcommand*{\@house}[2]{%
  % #1: math style
  % #2: expression that gets the "house"
  % get the line width of `\overline' in the current math font size
  \dimen@=\fontdimen8 %
      \ifx#1\scriptscriptstyle\scriptscriptfont
      \else\ifx#1\scriptstyle\scriptfont
      \else\textfont\fi\fi
      3 %
  \sbox0{%
    $#1%
      \vrule width\dimen@\relax
      \overline{%
        \kern2\dimen@
        \begingroup % to keep changes of \dimen@ in #2 local
          #2%
        \endgroup
        \kern2\dimen@
      }%
      \vrule width\dimen@\relax
      \mathsurround=1.5\dimen@ % outside margin
    $%
  }%
  % TeX adds an empty space above `\overline', it needs to be
  % removed to get the correct height for the `\vrule's
  \ht0=\dimexpr\ht0-\dimen@\relax
  \dp0=\dimexpr\dp0+2\dimen@\relax
  \vbox{%
    \kern\dimen@ % reinsert previously removed space
    \copy0 %
  }%
}

\begin{document}
\[
  \textstyle % same size as \displaystyle
  \house{\alpha + \beta}
  \stackrel{\mbox{\tiny T}}{=}
  \house{\alpha} + \house{\beta}^n
\]
\[
  \scriptstyle
  \house{\alpha + \beta}
  \stackrel{\mbox{\tiny S}}{=}
  \house{\alpha} + \house{\beta}^n
\]
\[
  \scriptscriptstyle
  \house{\alpha + \beta}
  \stackrel{\mbox{\tiny SS}}{=}
  \house{\alpha} + \house{\beta}^n
\]
\[
  \def\x{\frac{\house{\alpha + \beta}}{\house{\alpha} + \house{\beta}}}
  \x, \frac{\x}{\x} 
\]
\[
  \underbrace{\overline{\alpha^2}, \house{\alpha^2}}_{\mbox{\tiny cramped}} \ne
  \overline{\mbox{$\alpha^2$}}, \house{\mbox{$\alpha^2$}}
\]
\end{document}

Best Answer

Related Solutions

[Tex/LaTex] Currency symbol: French franc

Example for siunitx and pdfLaTeX

[Tex/LaTex] How to typeset the house of an algebraic number

Line width

\overline

Spacings

Related Question

Example for `siunitx` and pdfLaTeX

`\overline`