Creating commands for frame grids

Question

From Jake's answer to Drawing on an image with TikZ , I learned how to display gridlines on my beamer slides during development. It has greatly helped me in precise positioning of tikz nodes and objects. The code that I slightly modified and am using now, is:

\begin{tikzpicture}[remember picture, overlay]
    \draw[help lines,xstep=.25,ystep=.25,gray!20] (current page.south west) grid (current page.north east);
    \draw[help lines,xstep=1,ystep=1,gray] (current page.south west) grid (current page.north east);
    \foreach \x in {-15,-14.5,...,15} {
        \node [anchor=north, gray] at (\x,0) {\tiny \x};
        \node [anchor=east,gray] at (0,\x) {\tiny \x};
    }
\end{tikzpicture}

which, on a slide, looks like this:

Now, I find myself repeatedly adding these lines manually for each slide and commenting them out when I'm done. It's getting cumbersome, and also causing my file to bloat. I would like to be able to toggle gridlines on and off with a single command. How can I:

• Convert the above snippet into a command that, if set in the preamble, turns gridlines on for all the slides (or frames) and
• If the command is called from inside a \begin{figure}...\end{figure}, turns it on only for that slide.

Needless to say, these shouldn't mess with any existing tikz figures on that slide.

---

For now, I've simplified a lot of the bloat by defining a new command:

\newcommand{\gridlines}{
    \begin{tikzpicture}[remember picture, overlay]
        \draw[help lines,xstep=.25,ystep=.25,gray!20] (current page.south west) grid (current page.north east);
        \draw[help lines,xstep=1,ystep=1,gray] (current page.south west) grid (current page.north east);
        \foreach \x in {-15,-14.5,...,15} {
            \node [anchor=north, gray] at (\x,0) {\tiny \x};
            \node [anchor=east,gray] at (0,\x) {\tiny \x};
        }
    \end{tikzpicture}
}

and just calling \gridlines before the \end{frame} in each slide. A big improvement over copying 4-5 lines of code each time, but still not as convenient as a global on/off option.

Ideally, I would like it to be applied last, so that it overlays on everything else on the slide. Would it be possible to hack/redefine \end{frame} so that it becomes \gridlines\end{frame} instead?

Answer 1

Well the remaining step is to put it in the background canvas.

\documentclass{beamer}
\usepackage{tikz}
\newcommand{\turntikzgridon}{
\setbeamertemplate{background canvas}{
    \begin{tikzpicture}[remember picture, overlay]
        \draw[help lines,xstep=.25,ystep=.25,gray!20] (current page.south west) grid (current page.north east);
        \draw[help lines,xstep=1,ystep=1,gray] (current page.south west) grid (current page.north east);
        \foreach \x in {-15,-14.5,...,15} {
            \node [anchor=north, gray] at (\x,0) {\tiny \x};
            \node [anchor=west,gray] at (0,\x) {\tiny \x};
        }
    \end{tikzpicture}
}
}
\newcommand{\turntikzgridoff}{\setbeamertemplate{background canvas}{}}
\begin{document}
\turntikzgridon %<--- Turn it on
\begin{frame}{Frame title}
    Some frame 1
\end{frame}

\begin{frame}{Frame title 2}
    Some frame 2
\end{frame}
\turntikzgridoff %<----- Turn it off
\begin{frame}{Frame title 3}
    Some frame 3
\end{frame}

\end{document}

If you want to apply different backgrounds,images etc. then you need to use \addtobeamertemplate which will also overwrite the grid.