TikZ multipart nodes: How to set text attributes (opacity) for some/all parts

Question

I am using TikZ with the rectangle split multipart node (detailed on pp 450ff in the PGF 2.1 documentation). I need to influence the text opacity of all parts, but whatever I try seems to work only on the text (=first) part of the multipart node:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{tikz}
\usetikzlibrary{shapes.multipart}

\begin{document}
  \begin{tikzpicture}
    \node[rectangle split, rectangle split parts=2, draw, text opacity=0.5]{%
      transparent :-)
      \nodepart{two}
      not transparent :-(
    };
  \end{tikzpicture}
\end{document}

results in:

I have also tried \nodepart[text opacity=0.5]{two} and even Heiko Oberdiek's transparent package to set the text transparency manually, which, however does not seem to play together with PGF. There also seem to be no every ... styles for the additional parts of the rectangle split node.

I must be overlooking something.

Answer 1

See the edit history for my confusion.

This can be used for changing the color etc. of the parts independently (for which there was a question recently but I couldn't spot it).

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes.multipart}

\begin{document}
  \begin{tikzpicture}
    \node[rectangle split, rectangle split parts=2, draw,thick,text opacity=0.2]{%
      transparent :-)
    \nodepart{two}
        \begin{pgfinterruptpicture}\pgfsetfillopacity{0.2}
        now transparent :-)
        \end{pgfinterruptpicture}
    };
  \end{tikzpicture}
\end{document}

A little bit more automated solution is to make a macro that reads the opacity from the first node part

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes.multipart}
\makeatletter
\newcommand{\tnpa}[1]{
        \begin{pgfinterruptpicture}\pgfsetfillopacity{\tikz@textopacity}
        #1
        \end{pgfinterruptpicture}
}
\makeatother

\begin{document}
  \begin{tikzpicture}
    \node[rectangle split, rectangle split parts=2, draw,thick,text opacity=0.1]{
      Transparent \nodepart{two}\tnpa{Together}
    };
  \end{tikzpicture}
\end{document}

Hence, it needs the second node content to be contained in a macro argument.

Answer 2

A pretty hacky workaround is to render the text inside a nested tikzpicture. In this case the fact that nesting tikzpictures leads to an (often unexpected) inheritance of settings even serves the actual purpose:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{tikz}
\usetikzlibrary{shapes.multipart}

\begin{document}
  \begin{tikzpicture}[every two node part/.style={text opacity=0.5}]
    \node[rectangle split, rectangle split parts=2, draw, text opacity=0.5]{%
      transparent :-)
      \nodepart{two}
      not transparent :-(
    };
  \end{tikzpicture}
  \begin{tikzpicture}[every two node part/.style={text opacity=0.5}]
    \node[rectangle split, rectangle split parts=2, draw, text opacity=0.5]{%
      transparent :-)
      \nodepart{two}
      \tikz[]\node[inner sep=0pt, outer sep=0pt, text depth=0pt]{not not transparent :-(};%
    };
  \end{tikzpicture}
\end{document}

Some more hacking would be necessary to get the size of the node correctly. Well, I certainly would prefer a cleaner solution anyway.

Answer 3

I submitted a bug report at the Sourceforge page.

A temporary workaround would be to put the following into your preamble:

\makeatletter
\def\tikz@nodepart@continue{%
  \global\let\tikz@fig@continue=\tikz@fig@continue@orig%
  % Now start new box:
   \expandafter\setbox\csname pgfnodepart\tikz@nodepart@name box\endcsname=\hbox%
      \bgroup%
        \tikzset{every \tikz@nodepart@name\space node part/.try}%
        \expandafter\tikzset\expandafter{\tikz@nodepart@options}%
        % ---- begin added lines
        \ifx\tikz@textopacity\pgfutil@empty%
        \else%
          \pgfsetfillopacity{\tikz@textopacity}%
          \pgfsetstrokeopacity{\tikz@textopacity}%
        \fi%
        % ---- end added lines
        \pgfinterruptpicture%
          \tikz@textfont%  
          \ifx\tikz@text@width\pgfutil@empty%
          \else%
            \begingroup%
                \pgfmathsetlength{\pgf@x}{\tikz@text@width}%
              \pgfutil@minipage[t]{\pgf@x}\leavevmode\hbox{}%
                \tikz@text@action%
          \fi%
          \bgroup%
            \aftergroup\unskip%
            \ifx\tikz@textcolor\pgfutil@empty%
            \else%
              \pgfutil@colorlet{.}{\tikz@textcolor}%
            \fi%
            \pgfsetcolor{.}%
            \setbox\tikz@figbox=\box\pgfutil@voidb@x%
            \tikz@uninstallcommands%
            \tikz@atbegin@node%
            \aftergroup\tikz@fig@collectresetcolor%
            \tikz@halign@check%
            \ignorespaces%
}
\makeatother

Everything except for the marked code is copied from tikz.code.tex (the marked code is also from that file, but taken from the definition of \tikz@do@fig).

With this your code produces