\begin{tikzpicture}[x=1ex,y=1ex,baseline={([yshift=-.5ex]current bounding box.center)}]
    \coordinate (v);
    \coordinate[left=2 of v] (v1);
    \coordinate[right=2 of v] (v3);

    \draw (v1) to (v3);
    \filldraw (v1) circle(1pt);
    \filldraw (v3) circle(1pt);
    \filldraw (v) circle(1pt);

\end{tikzpicture}%