# pgf gif explanation [closed]

I am pretty new to latex and pgfplots. I am trying to make a gif. Can anyone please explain what is the function of <\fr> in pgfonlayer section of the following code?

\documentclass[hyperref={pdfpagelabels=false}]{beamer}
\usepackage{lmodern}

\usepackage{tikz}
\usetikzlibrary{arrows,shapes}

\tikzstyle{selected edge} = [draw,line width=5pt,-,red!50]

\usetheme{Frankfurt}

\tikzset{
error_00/.style={color=blue,thin},
}
\begin{document}
\pgfdeclarelayer{background}
\pgfsetlayers{background,main}

\begin{frame}
\begin{figure}
\begin{tikzpicture}[scale=1]

\foreach \pos/\name in {{(-12.117,45.857)/a}, {(-12.117,45.857)/b}, {(-7.809,45.857)/c}}
\node (\name) at \pos {};

\draw[x=1 cm,y=1 cm,error_00] (-10.628,45.857) -- (-7.809,45.857);
\begin{pgfonlayer}{background}
\foreach \source / \dest / \fr in {a/b/1/, b/c/2/}
\path<\fr>[selected edge] (\source.center) edge (\dest.center);
\end{pgfonlayer}
\end{tikzpicture}
\end{figure}
\end{frame}
\end{document}


I compile the file from this link: https://martin-thoma.com/how-to-visualize-graph-algorithms-with-latex . Additionally, I do not want to make the red line blink. I just want it to appear. Any ideas to achieve it with minimal amount of change. Thanks in advance.

## closed as unclear what you're asking by user36296, Troy, Phelype Oleinik, Bobyandbob, gusbrsMay 4 '18 at 22:34

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

• \source / \dest / \fr / \pos are variables within the loop. They will be in {a/b/1/, b/c/2/}. So \fr will loop as 1 and 2 and so make sense to use it in <> overlay specification. – Sigur Jul 1 '17 at 15:29
• thanks for explaining. Is it possible to make it not blink. The red line would just appear and then stay there. – tt_pre Jul 1 '17 at 15:34
• Make it <\fr->. – TeXnician Jul 1 '17 at 15:51
• @Sigur I tried with <1->, it does not work. I just get one page. I want the red line to appear first and then stay there forever. removing <> leads to compilation error. Thanks. – tt_pre Jul 1 '17 at 15:59
• @tt you need to provide a MWE, otherwise it would be difficult to trace your code. I always found it useful to prepare a MWE, because it always help to understand the problem better, and sometimes, it solved the problem. – berkus Jul 1 '17 at 16:07