Rounded corners only at one side of a TikZ node

Question

How can I make rounded corners at one side (only right, only left)?

\documentclass{minimal}
\usepackage{tikz}
\begin{document}
    \begin{tikzpicture}
        \node [fill=gray, rounded corners=10pt]{

        };
    \end{tikzpicture}
\end{document}

Answer 1

This is possible with the rounded rectangle shape type:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{positioning,shapes.misc}
\begin{document}

\begin{tikzpicture}[every node/.style={fill=gray, rounded rectangle, minimum width=2cm, minimum height=1cm}]
    \node [](A){};
    \node [rounded rectangle west arc=none, below=of A](B){};
    \node [rounded rectangle east arc=none, below=of B]{};
\end{tikzpicture}

\end{document}

See Section 48.8 of the TikZ Manual for further options.