[Tex/LaTex] How to create new commands in TikZ

tikz-pgf

I am new to the use of TikZ. I have been evaluating the TikZ-KTikZ combination, over the last 2 days, as an alternative to Xfig, which I have used for 17 years. I have managed to create a grid structure using the following code:

\begin{tikzpicture}
\newcommand{\GL}{5};
\draw [step=0.1, help lines,red!20] (-\GL,-\GL) grid (\GL,\GL);
\draw [step=1.0, help lines,red!40] (-\GL,-\GL) grid (\GL,\GL);
\draw [step=\GL.0, help lines,red!100] (-\GL,-\GL) grid (\GL,\GL);
\foreach \x in {-\GL,...,\GL} { \draw node at (\x,-\GL) [label=below:{\tiny $\x.0$}]{}; };
\foreach \x in {-\GL,...,\GL} { \draw node at (\x,\GL) [label=above:{\tiny $\x.0$}] {}; };
\foreach \y in {-\GL,...,\GL} { \draw node at (-\GL,\y) [label=left:{\tiny $\y.0$}]  {}; };
\foreach \y in {-\GL,...,\GL} { \draw node at (\GL,\y) [label=right:{\tiny $\y.0$}]  {}; };
\end{tikzpicture}

I like using the grid structure because it enables me to place my picture elements in the {tikzpicture} environment quickly. However, I have to comment it out after drawing my picture. I would like to package the above code into a single flexible command which I can insert into the {tikzpicture} and comment out quickly when I am done.

Could someone with a lot of experience in TikZ advise me on how I could package the above code into a single command which could accept optional parameters such as Xmin, Xmax, Ymin, Ymax and grid color, with default values.

Any help would be greatly appreciated.

Best Answer

Here is a solution via pgfkeys.

First, I create the new family mygrid, I define some keys with their initial values in this family and I define the new command \mygridset to use this family: 

\pgfkeys{
  mygrid/.is family,
  mygrid,
  min x/.initial=-5,
  max x/.initial=5,
  min y/.initial=-5,
  max y/.initial=5,
  small step/.initial=.1,
  step/.initial=1,
  big step/.initial=5,
  color/.initial=red,
}
\newcommand\mygridset[1]{\pgfkeys{mygrid,#1}}

Then I define the new command \mygrid with an empty optional parameter. The first lines of this command (the call to \mygridset) changes the values of the keys via #1 then store the value of each key in a macro. The last lines draw the grid with these values.

\newcommand\mygrid[1][]{
  \mygridset{#1,
    min x/.get=\gridminx,
    max x/.get=\gridmaxx,
    min y/.get=\gridminy,
    max y/.get=\gridmaxy,
    small step/.get=\gridsmallstep,
    step/.get=\gridstep,
    big step/.get=\gridbigstep,
    color/.get=\gridcolor
  }

  \draw [step=\gridsmallstep, help lines,\gridcolor!20]
  (\gridminx,\gridminy) grid (\gridmaxx,\gridmaxy);
  \draw [step=\gridstep, help lines,\gridcolor!40]
  (\gridminx,\gridminy) grid (\gridmaxx,\gridmaxy);
  \draw [step=\gridbigstep, help lines,\gridcolor!100]
  (\gridminx,\gridminy) grid (\gridmaxx,\gridmaxy);
  \foreach \x in {\gridminx,...,\gridmaxx} {
    \node[below,font=\tiny] at (\x,\gridminy) {$\x$};
    \node[above,font=\tiny] at (\x,\gridmaxy) {$\x$};
  };
  \foreach \y in {\gridminy,...,\gridmaxy} {
    \node[left,font=\tiny] at (\gridminx,\y) {$\y$};
    \node[right,font=\tiny] at (\gridmaxx,\y) {$\y$};
  };
}

Here is a complete example (3 pages) to illustrate the usage:

enter image description here

enter image description here

enter image description here

And the complete code:

\documentclass[tikz]{standalone}

\pgfkeys{
  mygrid/.is family,
  mygrid,
  min x/.initial=-5,
  max x/.initial=5,
  min y/.initial=-5,
  max y/.initial=5,
  small step/.initial=.1,
  step/.initial=1,
  big step/.initial=5,
  color/.initial=red,
}
\newcommand\mygridset[1]{\pgfkeys{mygrid,#1}}
\newcommand\mygrid[1][]{
  \mygridset{#1,
    min x/.get=\gridminx,
    max x/.get=\gridmaxx,
    min y/.get=\gridminy,
    max y/.get=\gridmaxy,
    small step/.get=\gridsmallstep,
    step/.get=\gridstep,
    big step/.get=\gridbigstep,
    color/.get=\gridcolor
  }

  \draw [step=\gridsmallstep, help lines,\gridcolor!20]
  (\gridminx,\gridminy) grid (\gridmaxx,\gridmaxy);
  \draw [step=\gridstep, help lines,\gridcolor!40]
  (\gridminx,\gridminy) grid (\gridmaxx,\gridmaxy);
  \draw [step=\gridbigstep, help lines,\gridcolor!100]
  (\gridminx,\gridminy) grid (\gridmaxx,\gridmaxy);
  \foreach \x in {\gridminx,...,\gridmaxx} {
    \node[below,font=\tiny] at (\x,\gridminy) {$\x$};
    \node[above,font=\tiny] at (\x,\gridmaxy) {$\x$};
  };
  \foreach \y in {\gridminy,...,\gridmaxy} {
    \node[left,font=\tiny] at (\gridminx,\y) {$\y$};
    \node[right,font=\tiny] at (\gridmaxx,\y) {$\y$};
  };
}

% a style to memorize some change to the default values
\mygridset{
  a grid/.style={
    min x=-3,
    max x=3,
    min y=-3,
    max y=3,
    small step=.2,
    step=1,
    big step=2,
    color=orange,
  }
}

\begin{document}
\begin{tikzpicture}
  % a grid with default values
  \mygrid
\end{tikzpicture}
\begin{tikzpicture}
  % a grid with specific values 
  \mygrid[min x=-3, max x=2,min y=-2,max y=1,color=blue]
\end{tikzpicture}
\begin{tikzpicture}
  % a grid using the `a grid` style
  \mygrid[a grid]
\end{tikzpicture}
\end{document}
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