Graphics, Figures & Tables ⇒ predefining colors in TikZ

[Antoine C]

[This is my very first question, so please judge me charitably if I am not presenting it in the expected format!]

I am running into problem when using a color in TikZ which I have predefined using conditionals. The message I get is

Package pgfkeys Error: I do not know the key '/tikz/ green ' and I am going t
o ignore it. Perhaps you misspelled it.

In the minimal example below, the first call to TikZ works fine, but not the second. I tried using {...} but it doesn't seem to do anything.

Code: Select all

\documentclass{minimal}
\usepackage{tikz}
\usepackage{xcolor}
\begin{document}
\def\mycolor#1{\ifnum#1=0
green
\else
red
\fi
}
\def\somecolor{green}
\tikz \fill[\somecolor](0,0) rectangle (1,1);
\tikz \fill[\mycolor0](0,0) rectangle (1,1);
\end{document}

[rais]

Welcome aboard

Your definition of \mycolor introduces whitespace at the end of the color name.
Without this space it works for me:

Code: Select all

\documentclass{minimal}
\usepackage{tikz}
\def\mycolor#1{%
  \ifnum#1=0
    green%
  \else
    red%
  \fi
}
\begin{document}
\tikz \fill[\mycolor1](0,0) rectangle (1,1);
\tikz \fill[\mycolor0](0,0) rectangle (1,1);
\end{document} 

KR
Rainer