# How can I save the bounding box of a TikZpicture and use in other TikZpicture

I need 2 different TikZpictures with the same bounding box (the one of the first TikZpicture) because I need a perfect vertical alignment of the subfigures side by side.

Please, how can I handle this?

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Note that it is unusual around here to sign your questions (as there is already a box with your username below it) or to have any greeting. – lockstep Mar 2 '11 at 15:48
– Martin Scharrer May 6 '11 at 11:11

You can use the \useasboundingbox command in the second picture to set the bounding box. Should be the first command in the picture.

\useasboundingbox (0,0) rectangle (<width of first picture>,<height of first picture>);


If you don't know the dimensions of the first picture you can get them from the current bounding box node. Using remember picture you can then access this information in the second node.

The code below will set the accept same bounding box for the second picture.

\documentclass{article}
\usepackage{tikz}
\begin{document}
\fbox{%
\begin{tikzpicture}
\draw (-1,-1) -- (5,5);
% more drawing commands ...
\coordinate (FIRST NE) at (current bounding box.north east);
\coordinate (FIRST SW) at (current bounding box.south west);
\end{tikzpicture}
}
\fbox{%
\begin{tikzpicture}
\useasboundingbox (FIRST SW) rectangle (FIRST NE);
\draw (0,0) -- (1,1);
\end{tikzpicture}
}
\end{document}


This works if both pictures use only positive coordinates. Adjustment must be made if this isn't the case.

The \fbox commands are only to display the bounding box and are not really required.

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Now I know how to use pgf to avoid \newbox :) but you need to compile twice. – Alain Matthes Mar 2 '11 at 16:05
@Martin: The result is incorrect for me, the second line is out of the second box ? – Alain Matthes Mar 2 '11 at 16:11
@Altermundus: You don't need to compile it twice. It works fine in the first run. Maybe you are confusing remember picture with overlay? – Martin Scharrer Mar 2 '11 at 16:15
@Altermundus (and Martin): It seems this solution only works correctly on the first compile. Compiling it again moves the short line down. Removing [remember picture] makes it work, though. Funny... – Jake Mar 2 '11 at 16:15
@Jake,Altermundus: I updated my example to the simple version I had before. It only works for positive coordinates, but shows that the principle works. – Martin Scharrer Mar 2 '11 at 16:18

Another way to do it is to use a single tikzpicture environment and one scope environment:

\begin{tikzpicture}
% TikZ code for first picture
\begin{scope}[xshift=5cm]
% TikZ code for second picture
\end{scope}
\end{tikzpicture}


Then the points plotted at (x,y) in each scope will be exactly 5cm apart.

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The code of Martin is correct but if you want to know the width and the height of the picture, you can use

\newbox\mybox
\setbox\mybox=\hbox{\begin{tikzpicture}
...
\end{tikzpicture}}


Now you get the width and the height of picture with

\wd\mybox
\ht\mybox
\dp\mybox


The height is \dp + \ht. I don't know if pgf/TikZ gives the height and the width directly.

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