# Symbol semi-circ, semi-bullet

I would like to create a LaTeX symbol that is mixing both \circ and \bullet. I want it to be a black circle, the size of \circ, with only the lower half filled in black, as on this image.

Do you have ideas about doing this in a not too complicated way?

• Welcome to tex.sx. This symbol doesn't seem to be in Unicode. Somebody (else) can probably tell you how to draw it with tikz. Jun 5 at 17:31

We can superimpose a \circ to a clipped \bullet; here \ooalign is our friend.

\documentclass{article}
\usepackage{amsmath,trimclip}

\makeatletter
\DeclareRobustCommand{\circbullet}{\mathbin{\vphantom{\circ}\text{\circbullet@}}}
\newcommand{\circbullet@}{%
\check@mathfonts
\m@th\ooalign{%
\clipbox{0 0 0 {\dimexpr\height-\fontdimen22\textfont2}}{$\bullet$}\cr
$\circ$\cr
}%
}
\DeclareRobustCommand{\bulletcirc}{\mathbin{\text{\bulletcirc@}}}
\newcommand{\bulletcirc@}{%
\check@mathfonts
\m@th\ooalign{%
\raisebox{\fontdimen22\textfont2}{\clipbox{0 {\fontdimen22\textfont2} 0 0}{$\bullet$}}\cr
$\circ$\cr
}%
}
\makeatother

\begin{document}

$a\circbullet b\bulletcirc c$

$\scriptstyle a\circbullet b\bulletcirc c$

$\scriptscriptstyle a\circbullet b\bulletcirc c$

\end{document}


I also provided the inverse form.

The fontaewome5 package offers the \faAdjust icon that, if rotated by 90 degrees, looks simliar to the image in your question:

\documentclass{article}
\usepackage{graphicx}
\usepackage{fontawesome5}
\begin{document}
\end{document}


The wasysym package has \LEFTcircle. Note that the capitalization of the command names is important. You can rotate this circle to get a bottom circle. They are a bit bigger than \circ and \bullet so you can scale them to match the size. They are also on the baseline so you can raise them a bit. Alternatively you can use wasysym also for the fully closed and open circles, then they match automatically. This may be a bit more consistent because the lines are a bit thinner in the wasysym circles as compared to \circ.

MWE:

\documentclass{article}
\usepackage{graphicx}
\usepackage{wasysym}
\begin{document}
Wasysym circles: \LEFTcircle\ \rotatebox[origin=c]{90}{\LEFTcircle} \Circle\ \CIRCLE

Scaled to match circ and bullet: \raisebox{1pt}{\scalebox{0.6}{\LEFTcircle}} \raisebox{1pt}{\scalebox{0.6}{\rotatebox[origin=c]{90}{\LEFTcircle}}} $\circ\ \bullet$

\def\downcirc{\raisebox{1pt}{\scalebox{0.6}{\rotatebox[origin=c]{90}{\LEFTcircle}}}}

As command: $\downcirc \circ \bullet$

\end{document}


Stix and oplotsymbl package define also the symbols "semi-circ, semi-bullet" that you can use also with \scriptstyle or with the option \scriptscriptstyle.

\documentclass[a4paper,12pt]{article}
\usepackage{stix}
\usepackage{oplotsymbl}

\begin{document}
$\circletophalfblack$, $\circlebottomhalfblack$

$\circletfillha$, $\circletfillhb$
\end{document}