TikZ: How to avoid white space when using "seam allowance"?

Question

Assumed we have this very simple Minimum Working Example (MWE) to draw a straight line:

\documentclass[tikz]{standalone}
\usetikzlibrary{intersections,decorations.pathmorphing}

\begin{document}
    \begin{tikzpicture}
        \draw[draw=red, line width=5pt]   (-10,6) -- (50,6);
    \end{tikzpicture}
\end{document}

Screenshot of the result:

As you can see, the line reaches the left and right page borders of the TikZ-layout as desired.

However, if I edit the upper MWE and add a seam allowance to create a second (parallel) line, the left and right page borders will suddenly increase:

\documentclass[tikz]{standalone}
\usetikzlibrary{intersections,decorations.pathmorphing}

\begin{document}

    \tikzset{%
      seam/.style={double distance=\seamallowance,draw},%
      seam allowance/.store in=\seamallowance,%
      seam allowance=5cm,%
    }

    \begin{tikzpicture}
        \draw[seam, draw=red, line width=5pt]   (-10,6) -- (50,6);
    \end{tikzpicture}

\end{document}

Screenshot of the result:

As you can see, those ugly white spaces on the left and right side have appeared.

Question:

How can I avoid this behavior, so the new line won't create any additional white space on the sides anymore?

You have whitespace in the first example as well, but just a little bit. I think this has to do with the line caps. If you set line cap=rect you won't get the whitespace, but you will also get a red rectangle, not just red lines on the top and bottom, so that doesn't really help. — Torbjørn T., Jul 20 '19 at 07:29
See https://tex.stackexchange.com/questions/130456/tikz-double-lines-are-shifted — Ulrike Fischer, Jul 20 '19 at 08:20

score 6 · Accepted Answer · answered Jul 20 '19 at 08:58

The background of the bounding box calculation is described in tikz: double lines are shifted.

The solution from Loop Space works here too, but you need to add a piece of the line as a path to avoid that standalone gets confused when the tikzpicture has suddenly no height anymore:

\documentclass[tikz]{standalone}
\usepackage{tikz}
\usetikzlibrary{intersections,decorations.pathmorphing}
\makeatletter
\tikzset{
  only coordinates are relevant/.is choice,
  only coordinates are relevant/.default=true,
  only coordinates are relevant/true/.code={%
    \tikz@addmode{\pgf@relevantforpicturesizefalse}},
  only coordinates are relevant/false/.code={%
    \tikz@addmode{\pgf@relevantforpicturesizetrue}}
}
\makeatother
\begin{document}

    \tikzset{%
      seam/.style={double distance=\seamallowance,draw,},%
      seam allowance/.store in=\seamallowance,%
      seam allowance=5cm,%
    }

    \begin{tikzpicture}
        \path[seam,line width=5pt]   (10,6); %so that the picture has the correct height ...
        \draw[seam, draw=red, line width=5pt,only coordinates are relevant]   (-10,6) -- (50,6);
    \end{tikzpicture}

\end{document}

TikZ: How to avoid white space when using "seam allowance"?

1 Answers1