TikZ: "Inline" pgfonlayer?

Question

Possible Duplicate:
“Z-level” in TikZ

When using layers in tikz I usually do the following:

\begin{pgfonlayer}{background}
    \draw[red] (0,0)--(1,0);
\end{pgfonlayer}

Is there a way of using the layers inline? e.g.:

\draw[layer=background, red] (0,0) -- (1,0);

Answer 1

I don’t know a way for this. My workaround is creating new commands for layers:

\documentclass{minimal}

\usepackage{tikz}
    \pgfdeclarelayer{background}
    \pgfsetlayers{main,foreground}
    \newcommand{\onlayer}[2]{%
        \begin{pgfonlayer}{#1}%
        #2%
        \end{pgfonlayer}%
    }
    \newcommand{\bglayer}[1]{%
        \begin{pgfonlayer}{background}%
        #1%
        \end{pgfonlayer}%
    }

\begin{document}
\begin{tikzpicture}
    \fill (0,0) rectangle (2,2);
    \bglayer{\fill [gray] (1,1) rectangle (3,3);}
\end{tikzpicture}
\end{document}

It’s not as comfortable as your inline version but better (shorter) than using the pgfonlayer environment …

Edit Another way is shown in "Z-level" in TikZ