[Tex/LaTex] Insert a TikZ picture from an external file

graphicstikz-pgf

I tried to search a bit, but i guess my poor English prevented me from finding the answer.

I made a few tikz pictures that i want to use in my report. I made the tikz pictures in separate tex files so i don't have to compile my whole report just to check the image.

But now, when copy pasting the tikz code into my report the image looks different. Some stuff moved or is not in the right position.

I was hoping this could be fixed by instead of putting the tikz code in my report, inserting the tikz.tex file similar to \include or \insert.

This way i hope my picture will look like it does in the separate file and i will not have to compile it when i compile my report.

I guess this is possible, but i just don't know how and i could not find it. Does anyone know_

Best Answer

Your problem of different results is most likely due to different font sizes or other settings in the picture and main file. This is especially true if you are using em or ex as placing units. I can't tell more about it without knowing your code.

However, you can avoid this by ensuring identical settings in both files. Should this not be possible you can still compile the external picture to a PDF an include it using \includegraphics. There is a small size overhead coming with it, but it should not be an issue. It has actually a nice speed benefit with larger TikZ pictures.

For external TikZ pictures I recommend the following procedure: Use the standalone class for the TikZ picture file and then use the standalone package in the main file. This way you can use \input to read the external file while its preamble is ignored or even copied to the main preamble automatically. When the external picture is compiled by its own standalone makes sure it is placed on a tight page using the preview package. The resulting PDF pictures are very suitable to be included into the main document. I'm currently working on a new version of standalone which gives you an \includestandalone with an option if the .tex or .pdf should be included!

Update Apr 2012:

The v1.0 of the standalone package now provides \includestandalone which works like \includegraphics, but with standalone files (and similar). The package has a mode=<mode> option which controls if the standalone source file is compiled with the main document (mode=tex) or a PDF version is included as image (mode=image). The PDF can also be build if required (mode=build, mode=buildnew or mode=buildmissing).

An important option for this question is obeyclassoptions, which will try to obey all class option used in the standalone file even if this file is compiled as part of the main document and therefore the standalone preamble is ignored. This means if the external files use \documentclass[12pt]{standalone} then a 12pt font size is also used when this file is included (as source code) in the main document.

edit:

I believe the TikZ key external/mode=graphics if exists does exactly what you want. (See the TikZ/PGF Manual v2.10 Section 32.4.4, page 349.) Try the following for your example:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{external}
\tikzexternalize
\tikzset{external/mode=graphics if exists}
\begin{document}

\def\mypic#1{
  \begin{tikzpicture}\clip (-1,-1) rectangle (1,2);
    \draw[red] plot (\x,{#1});
\end{tikzpicture}
}

\mypic{(\x)^2}
\begin{tikzpicture}\clip (-1,-1) rectangle (1,2);
\draw[red] plot (\x,{\x*\x*\x});
\end{tikzpicture}

\end{document}

original answer:

If you know that the external graphics has a particular extension (as seems to be given in your case) you can use \IfFileExists{<file>}{}{}, e.g.

\documentclass{article}

\usepackage{tikz}

\begin{document}

\IfFileExists{./logo.pdf}{%
  \includegraphics{logo}
}{%
  \begin{tikzpicture}
    \draw (0,0) rectangle (1,1);
  \end{tikzpicture}
}

\end{document}

[Tex/LaTex] Saving tikz figures in external file

Simple answer, you can do both. However, in a very closer inspection, each has its own advantages and disadvantages.

Method 1

%&pdflatex
% !TeX TXS-program:compile = txs:///pdflatex/[--shell-escape]
\documentclass{scrreprt}
\usepackage{tikz}
\usepackage{lipsum}
\tikzset{every picture/.style={line width=0.75pt}} %set default line width to 0.75pt        
\usetikzlibrary{external}
\tikzexternalize[prefix=tikzexfig/]
\usepackage{standalone}
\begin{document}
\chapter{Foo}
\lipsum[1]
\begin{figure*}[h]
    \centering{
        \input{ex.tex}
        \caption{This is just a part of the total picture.}
        \label{f1}
    }
\end{figure*}
\lipsum[2]
\end{document}

Note: tikzexfig is a folder within your master directory.

Update 1: You must escape the shell to compile the document.

ex.tex

 \begin{tikzpicture}[x=0.75pt,y=0.75pt,yscale=-1,xscale=1]
    %Shape: Rectangle [id:dp6874714272670446] 
    \draw   (600.5,167) -- (608.5,167) -- (608.5,181.5) -- (600.5,181.5) -- cycle ;
    \end{tikzpicture}

Advantages:

Easier in-line compilation due to smart caching of figures in pdf.

Disadvantages:

When using for publications, you most certainly have to use standalone package to compile them separately.
Memory limit would be reached (pdftex/LaTeX).
When editing, you must delete the already generated pdf's manually. (I am not yet aware of a better alternative to automate it, yet). I had a good discussion with @DavidCarlisle on putting a wrapper around it, as similar to psfrag. However, the result was a terrible failure ;-).
First compilation with all the figues will take a hell-a-lot of time. Subsequent compilations are much faster.

Method 2

I am not going to discuss it, as it is the standard standalone package implementation.

\documentclass{standalone}
\usepackage{tikz}
\begin{document}
 \begin{tikzpicture}[x=0.75pt,y=0.75pt,yscale=-1,xscale=1]
    %Shape: Rectangle [id:dp6874714272670446] 
    \draw   (600.5,167) -- (608.5,167) -- (608.5,181.5) -- (600.5,181.5) -- cycle ;
    \end{tikzpicture}
\end{document}

Advantages:

Easier file-like externalisation.
Gives your output in different formats. For more info, visit the package documentation.
We can take the output and compile in shorter time.

Disadvantages:

Different sub-files. Atleast, I am not yet aware to include it as in Method 1.

Disclaimer 1: I remember seeing somewhere that tikzexternal and standalone should not be used together. But I don't remember why and not sure of its impacts.

Disclaimer 2: With pdftex/LaTeX, memory limit is a common problem for both the methods per se.