Line width is ill-restored at the end of a pgfinterruptpath environment

[pgf-tikz-bot]

Migrated from SourceForge
Author: evan-aad
Timestamp: 2017-08-07 16:58:12.831000

Consider the following LaTeX manuscript featuring a TikZ picture that draws three parallel horizontal line segments. The second line segment is double-stroked. In the beginning of the picture, the line width is set to 2mm inside a pdfinterruptpath environment.

The expected behavior is that all three lines would have the same width. Instead, the 1st and 3rd lines have width 2mm, whereas the double-stroked line has width 0.4pt. See attached image file.

\documentclass{standalone}
\usepackage{tikz}
\begin{document}
    \begin{tikzpicture}
        \begin{pgfinterruptpath}
          \pgfsetlinewidth{2mm}
        \end{pgfinterruptpath}

        \draw (0,0) -- (1,0);
        \draw[double] (0,1) -- (1,1);
        \draw (0,2) -- (1,2);
    \end{tikzpicture}
\end{document}

This bug is due to the fact that the pgfinterruptpath environment attempts to restore the original line width at the end of the environment, but instead of doing it properly by calling \pgfsetlinewidth, it simply restores the macro \pgflinewidth. This causes a broken state: the effective line width is the one set inside the pgfinterruptpath environment, namely 2mm, but the \pgflinewidth macro expands to 0.4pt.

However, in my opinion, the way to fix this bug is not by using \pgfsetlinewidth at the end of the environment, but rather by not attempting to save-and-restore the line width to begin with, since no other path property (e.g. stroke color) gets this special treatment.

Specifically, in my opinion the bug should be fixed as follows.

1. In the definitions of \pgfinterruptpath delete the line \edef\pgfscope@linewidth{\the\pgflinewidth}%.
2. In the definition of \endpgfinterruptpath delete the line \global\pgflinewidth=\pgfscope@linewidth%.

[pgf-tikz-bot]

Migrated from SourceForge
Author: hmenke
Timestamp: 2018-12-27 22:05:18.836000

I'm not sure what should be the proper behaviour here. Both the current and your proposed behaviour seem broken to me.

[hmenke]

That is by design, pgfinterruptpath is not a scope. This works as expected.

\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
  \begin{scope}
    \begin{pgfinterruptpath}
      \pgfsetlinewidth{2mm}
      \draw (0,-1) -- (1,-1);
    \end{pgfinterruptpath}
  \end{scope}
  \draw (0,0) -- (1,0);
  \draw[double] (0,1) -- (1,1);
  \draw (0,2) -- (1,2);
\end{tikzpicture}
\end{document}

[hmenke]

@EvanAad Are you the same person as evan-aad on SourceForge?

[EvanAad]

I am the same person.

…

On Fri, Nov 29, 2019 at 1:02 AM Henri Menke ***@***.***> wrote: @EvanAad <https://github.com/EvanAad> Are you the same person as evan-aad on SourceForge? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#442?email_source=notifications&email_token=AFIRW75HMZPVPPSU4EW2E4DQWBEWNA5CNFSM4JSYQOE2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEFNRAZI#issuecomment-559616101>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AFIRW7ZB6QNT4IEHUCHW4STQWBEWNANCNFSM4JSYQOEQ> .

[hmenke]

@EvanAad Great! I've recently acted on some of the issues that you opened, but of course you weren't notified. Maybe you want to have a look and comment:
https://github.com/pgf-tikz/pgf/issues?q=is%3Aissue+sort%3Aupdated-desc+evan-aad

[EvanAad]

I'm afraid I haven't used PGF/TikZ since roughly the time I reported these issues. I'd be like a fish out of water going back to them at this point.

…

On Fri, Nov 29, 2019 at 9:52 AM Henri Menke ***@***.***> wrote: @EvanAad <https://github.com/EvanAad> Great! I've recently acted on some of the issues that you opened, but of course you weren't notified. Maybe you want to have a look and comment: https://github.com/pgf-tikz/pgf/issues?q=is%3Aissue+sort%3Aupdated-desc+evan-aad — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#442?email_source=notifications&email_token=AFIRW72T6QZ5M7JQSTOLI2TQWDC2TA5CNFSM4JSYQOE2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEFOEEZI#issuecomment-559694437>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AFIRW72POIPXFCNKUH6HC6DQWDC2TANCNFSM4JSYQOEQ> .