Take the 2-minute tour ×
TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. It's 100% free, no registration required.

Say I wanted to define a function in TiKz for drawing an eye:

\begin{tikzpicture}

%eye
\pgfmathsetmacro{\eyeSize}{1}
\pgfmathsetmacro{\ex}{0}
\pgfmathsetmacro{\ey}{1}
\pgfmathsetmacro{\eRot}{-10}
\pgfmathsetmacro{\eAp}{-55}
\draw[rotate around={\eRot:(\ex,\ey)}] (\ex,\ey) -- ++(-.5*\eAp:\eyeSize)
     (\ex,\ey) -- ++(.5*\eAp:\eyeSize);
\draw (\ex,\ey) ++(\eRot+\eAp:.75*\eyeSize) arc (\eRot+\eAp:\eRot-\eAp:.75*\eyeSize);

% IRIS
\draw[fill=gray] (\ex,\ey) ++(\eRot+\eAp/3:.75*\eyeSize) % start point
  arc (\eRot+180-\eAp:\eRot+180+\eAp:.28*\eyeSize);

%PUPIL, a filled arc 
\draw[fill=black] (\ex,\ey) ++(\eRot+\eAp/3:.75*\eyeSize) % start point
  arc (\eRot+\eAp/3:\eRot-\eAp/3:.75*\eyeSize);

\end{tikzpicture}

This is too long! How would I define a "function" in TiKz, so that I can call something \eye( \ex, \ey, \rotation, \eyeAperture ) to produce an eye?

share|improve this question
add comment

2 Answers

up vote 11 down vote accepted

Like this?

\documentclass[parskip]{scrartcl}
\usepackage[margin=15mm]{geometry}
\usepackage{tikz}

\begin{document}

\newcommand{\eye}[4]% size, x, y, rotation
{   \draw[rotate around={#4:(#2,#3)}] (#2,#3) -- ++(-.5*55:#1) (#2,#3) -- ++(.5*55:#1);
    \draw (#2,#3) ++(#4+55:.75*#1) arc (#4+55:#4-55:.75*#1);
    % IRIS
    \draw[fill=gray] (#2,#3) ++(#4+55/3:.75*#1) arc (#4+180-55:#4+180+55:.28*#1);
    %PUPIL, a filled arc 
    \draw[fill=black] (#2,#3) ++(#4+55/3:.75*#1) arc (#4+55/3:#4-55/3:.75*#1);
}

\begin{tikzpicture}
    \eye{1}{0}{1}{-10}
    \eye{2}{4}{0}{30}
    \eye{0.5}{0}{-3}{135}
    \eye{3}{4}{-4}{260}
\end{tikzpicture}

\end{document}

enter image description here

share|improve this answer
    
So "variables" can't have better names than #1, #2 etc? –  bobobobo Aug 10 '12 at 18:48
    
You can use pgfkeys of xkeyval. There you predefine keys (and probably default values), then you can use specify them by e.g. \eye[radius=4,x=2,y=3,rotation=135] –  Tom Bombadil Aug 10 '12 at 19:29
    
You could also do as a first thing in your command definition \pgfmathsetmacro{\radius}{#1}. That way you can use \radius instead of #1, the readability would definitively improve. –  Tom Bombadil Aug 24 '12 at 0:14
add comment

A complement to Tom's answer. I added pgfkeys stuff

\documentclass[parskip]{scrartcl}
\usepackage[margin=15mm]{geometry}
\usepackage{tikz}

  \makeatletter
\pgfkeys{/eye/.cd,
  x/.code           = {\def\eye@x{#1}},
  y/.code           = {\def\eye@y{#1}},
  rotation/.code    = {\def\eye@rot{#1}},
  radius/.code      = {\def\eye@rad{#1}}
  }

\newcommand{\eye}[1][]{% size, x, y, rotation  
\pgfkeys{/eye/.cd,
  x         = 0,
  y         = 0,
  rotation  = 0,
  radius    = 1
  } 
\pgfqkeys{/eye}{#1}   
   \draw[rotate around={\eye@rot:(\eye@x,\eye@y)}] 
         (\eye@x,\eye@y) -- ++(-.5*55:\eye@rad) 
         (\eye@x,\eye@y) -- ++(.5*55:\eye@rad);
   \draw (\eye@x,\eye@y) ++(\eye@rot+55:.75*\eye@rad) arc (\eye@rot+55:\eye@rot-55:.75*\eye@rad);
  % IRIS
   \draw[fill=gray] (\eye@x,\eye@y) ++(\eye@rot+55/3:.75*\eye@rad) arc (\eye@rot+180-55:\eye@rot+180+55:.28*\eye@rad);
  %PUPIL, a filled arc 
   \draw[fill=black] (\eye@x,\eye@y) ++(\eye@rot+55/3:.75*\eye@rad) arc (\eye@rot+55/3:\eye@rot-55/3:.75*\eye@rad);
}
\makeatother   

\begin{document}

\begin{tikzpicture}
    \eye[radius=1,y=1,rotation=-10]
    \eye[radius=2,x=4,rotation=30] 
\end{tikzpicture}

\end{document} 

enter image description here

share|improve this answer
    
You could use the .store in handler for those keys. Same effect, of course. –  Andrew Stacey Aug 11 '12 at 8:14
    
Thanks for the idea, I always use the same technics but it's interesting to know other methods ! –  Alain Matthes Aug 11 '12 at 8:53
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.