PGF align plain TeX

Question

I don't get the excepted result with the following code

\input tikz
\tikzpicture
  \node[draw,align=center] {Hello \hfil\break World};
\endtikzpicture
\bye

There is no break after Hello. I don't want to use text width and specify the width manually.

Answer 1

PGF/TikZ has some troubles (at least at the time of this writing; version 2.10) when used with the plain-format, unfortunately.

Your example works as \tikz[draw,align=center] {Hello\\ World};, but there are situations where surprising things will happen with plain-format:

\tikz\node[draw,align=center,text width=1cm] {Hello World};

The above will introduce an interesting (and annoyingly persistent) \parindent. A \noindent at the start of the node will do nothing. Same with \parindent0pt. Same with a style with execute at begin node for both of the previous. The \parindent0pt needs to be set before the \node command for it to work.

Another surprising thing one can run into with plain-format:

\tikz\node[draw,align=right,text width=1cm] {Hello World};

where PGF/TikZ will try to execute \raggedleft, a command which does not exist in plain.

Now, I think I remember reading somewhere that PGF/TikZ issues with plain are being fixed (or have already been fixed?), so the current CVS version might not exhibit these issues.