Plots and chapterspecific colors

Question

I have a color switching function that looks like this

\definecolor{chap1}{RGB}{68, 114, 148}
\definecolor{chap2}{RGB}{10,130,124}
\definecolor{chap3}{RGB}{250,72,46}
\definecolor{chap4}{RGB}{244,163,46}

\usepackage{etoolbox}
\newcommand{\basecolor}{
    \ifcase\arabic{chapter} black\or chap1\or chap2\or chap3\or chap4\else black\fi%
}

\newcommand{\chaptercolor}{\basecolor}

This lets me use \chaptercolor anywhere to get the color that has been chosen for this chaper depending on its position in the document. Works great, except for one thing.

I cannot get it to work with plots.

Take this simple plot as an example:

\tikzset{>=stealth}
\begin{tikzpicture}
    \begin{axis}[
            domain=0:1, range=0:1,
            axis lines=none,
          ]   
          \addplot [->] plot coordinates {(0,0) (0,1)}; 
          \addplot [->, color=\chaptercolor, fill=\chaptercolor, draw=\chaptercolor] plot coordinates {(0,0) (1,0)};
        \end{axis}
\end{tikzpicture}

This gives me the error Package xcolor Error: Undefined color ` chap2'.

With all the odd symbols in it.

If I use the color chap2 directly instead it works fine. It would also be great to have the plots always use \chaptercolor maybe by using \tikzset{}, but so far that gives even worse error messages.

Any input on how to fix this, or perhaps even a different approach to cycling the colors?

Edit:
Adding an identical color with a space in front of its name solves the problem.

\definecolor{ chap1}{RGB}{68, 114, 148}
\definecolor{ chap2}{RGB}{10,130,124}
\definecolor{ chap3}{RGB}{250,72,46}
\definecolor{ chap4}{RGB}{244,163,46}
\definecolor{chap1}{RGB}{68, 114, 148}
\definecolor{chap2}{RGB}{10,130,124}
\definecolor{chap3}{RGB}{250,72,46}
\definecolor{chap4}{RGB}{244,163,46}

A little inelegant, but it's not too bad since it's only in the preamble.

Answer 1

I think the problem comes from \basecolor definition. It inserts an empty space before color names which is the reason why \definecolor{ chap1}... works.

\documentclass{book}
\usepackage{pgfplots}

\definecolor{chap1}{RGB}{68, 114, 148}
\definecolor{chap2}{RGB}{10,130,124}
\definecolor{chap3}{RGB}{250,72,46}
\definecolor{chap4}{RGB}{244,163,46}

\usepackage{etoolbox}
\newcommand{\basecolor}{%
    \ifcase\value{chapter}
    black%
    \or% 
    chap1%
    \or% 
    chap2%
    \or% 
    chap3%
    \or% 
    chap4%
    \else% 
    black%
    \fi%
}

\newcommand{\chaptercolor}{\basecolor}

\begin{document}

\foreach \i in {1,...,5}
{
    \chapter{\i}
    \tikzset{>=stealth}
    \begin{tikzpicture}
        \begin{axis}[
                domain=0:1, range=0:1,
                axis lines=none,
              ]   
              \addplot [->] plot coordinates {(0,0) (0,1)}; 
              \addplot [->, color=\chaptercolor, fill=\chaptercolor, draw=\chaptercolor] plot coordinates {(0,0) (1,0)};
            \end{axis}
    \end{tikzpicture}
}
\end{document}