Symbol for encoding error: black diamond with white question mark �

Question

I would like to add this symbol: � to a beamer presentation. It is shown when something went wrong with the encoding.

Sadly, I can't simply include this symol:

[53]
! Package inputenc Error: Unicode char \u8:� not set up for use with LaTeX.
See the inputenc package documentation for explanation.

and I don't have any idea how to get it in LaTeX

(An image is not the solution I would like to use!)

Detexify didn't help either.

Description of the symbol (to make it easier to find):

• a black diamond with a white question mark within or
• a black sexagon with a white question mark
• seems to be "\xa0" in sed

How is this symbol � called? How can I print it with LaTeX?

Answer 1

Following David Carlisle's suggestion here's a TikZ solution:

\documentclass{standalone}

\usepackage{tikz}
% w/o following space!
\newcommand{\quem}{\tikz[baseline=(wi.base)]{\node[fill=black,rotate=45,inner sep=.1ex, text height=1.8ex, text width=1.8ex] {};%
\node[ font=\color{white}] (wi) {?};}}

\begin{document}

 Some  \quem Text

\end{document}

You may alter the size of the black triangle by playing with inner sep and keep in mind that there is no space an the end of the macro.

Answer 2

The symbol you actually pasted into this question is U+FFFD Thus is the Unicode replacement character that applications use as a substitute when they are otherwise confused. It doesn't have a default presentation as it is essentially a kind of control character. The font here is showing it in that form.

If you don't specifically need it as a single text character you could of course produce it in latex by including an image or by over-printing a white question mark over a black diamond.

So in pdflatex this works:

\documentclass{beamer} 

\usepackage[utf8]{inputenc}
\DeclareUnicodeCharacter{FFFD}{\colorbox{black}{\color{white}?}}

\usepackage{array}

\begin{document}      

% Methode 1                                             
\begin{frame}

This is U+FFFD (�)

\end{frame}
\end{document}

Obviously you can put more design into the white on black ? if needed, this just shows the basic idea.

Answer 3

and a solution without loading a bombastic package:

\documentclass{standalone}
\usepackage{graphicx,color}
\makeatletter
\newsavebox\Diam@nd \newlength\x@D\newlength\y@D
\newcommand\Quem{%
  \sbox\Diam@nd{\raisebox{-1ex}{\scalebox{1}[1.2]{\rotatebox{45}{\rule{1em}{1em}}}}}%
  \makebox[\wd\Diam@nd]{\makebox[0pt]{\usebox\Diam@nd}\makebox[0pt]{\textcolor{white}{?}}}}
\makeatother

\begin{document}

Some  \Quem\ Text \huge \Quem\ Text 

\end{document}

It also takes the fontsize into account

Answer 4

Over-printing a white question mark over a black diamond, as suggested by David Carlisle, could be accomplished by

\documentclass{article}

\usepackage{amssymb}
\usepackage{xcolor}
\usepackage{relsize}
\usepackage{xspace}

\newlength{\encerr}

\newcommand{\encodingerror}{%
  \hbox{%
    $\blacklozenge$%
    \settowidth{\encerr}{$\blacklozenge$}%
    \hspace{-0.77\encerr}%
    {\color{white}\textsmaller[2]{?}}%
   }%
  \xspace%
 }

\begin{document}

An \encodingerror occurred.

\end{document}

The xspace could also be used for bloodworks' answer, of course.