線の種類

普通の円

<script type="text/tikz">
\begin{tikzpicture}
\draw (0,0) circle (3);
\end{tikzpicture}
</script>

点線の円

<script type="text/tikz">
\begin{tikzpicture}
\draw[dashed] (0,0) circle (3);
\end{tikzpicture}
</script>

赤線の円

<script type="text/tikz">
\begin{tikzpicture}
\draw[red] (0,0) circle (3);
\end{tikzpicture}
</script>

太線の円

<script type="text/tikz">
\begin{tikzpicture}
\draw[ultra thick] (0,0) circle (3);
\end{tikzpicture}
</script>

赤くて太い点線の円

<script type="text/tikz">
\begin{tikzpicture}
\draw[red,dashed, ultra thick] (0,0) circle (3);
\end{tikzpicture}
</script>