# define color in pgfplots

I want to plot funtions and data with own colors using \definecolor{<name>}{<model>}{<value(s)>}. If I use this command in \tikzpicture it works. But if I use this command in pgfplots all defined colors are black. Why?

My Example (not wondering about some calculations - I need that for more complex functions and data plotting):

\documentclass[rgb]{standalone}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=1.13}
\usepackage{pgffor}
\usepackage{calc}
\usepackage{xcolor}
\usepackage{amsmath}
\usepackage{sistyle}

\newcommand{\thetamin}{-90}
\newcommand{\thetamax}{90}
\newcommand{\thetaminplusstep}{-80}

%======================================================================================

\begin{document}

\begin{tikzpicture}
\begin{axis}[title={Title},title style={text width=8cm,font=\tiny},ylabel={y}, xlabel={x}, legend style={cells={anchor=west}, legend pos=north west, font=\tiny}, xmin=-1, xmax=1, ymin=-1, ymax=1]
\foreach \i in {\thetamin,\thetaminplusstep,...,\thetamax}{
\newcount\k
\pgfmathsetmacro{\k}{\i/\thetamax}
\newcount\j
\j=400
\ifnum\i<0
\pgfmathsetmacro{\j}{-400*\i/\thetamin+800}
\else
\pgfmathsetmacro{\j}{(-400/\thetamax*\i)+800}
\fi
\definecolor{tmpcolor}{wave}{\j}
\colorlet{mycolor}[rgb]{tmpcolor}
%\addlegendentry{$\ang{\i}$};
}
\end{axis}
\end{tikzpicture}

\begin{tikzpicture}
\foreach \i in {\thetamin,\thetaminplusstep,...,\thetamax}{
\newcount\k
\pgfmathsetmacro{\k}{\i/\thetamax*2}
\newcount\j
\j=400
\ifnum\i<0
\pgfmathsetmacro{\j}{-400*\i/\thetamin+800}
\else
\pgfmathsetmacro{\j}{(-400/\thetamax*\i)+800}
\fi
\definecolor{tmpcolor}{wave}{\j}
\colorlet{mycolor}[rgb]{tmpcolor}
\draw[fill=mycolor] (0,\k) rectangle (1,\k+0.25);
\draw[black] (2.5,\k+0.15) node {\tiny $\ang{\i}$, wave: \j};
}
\end{tikzpicture}

\end{document}


As result I get:

I look forward to a useful answer.

anne

• Have you looked at the color maps section of the pgfplots manual? It is relatively easy to define a new color map yourself and then use that in a plot. – Alexander Jun 8 '16 at 11:07
• By the way, a completely unrelated comment: You're plotting straight lines with 100 samples each. You can save some computation time if you set samples=2 instead, and it won't affect the result. – Torbjørn T. Jun 9 '16 at 12:51

the problem caused in \foreach, also look at \foreach not behaving in axis environment

to solve the problem I use (during using colormaps)

\edef\temp{\noexpand\addplot[color of colormap={\l}, solid, mark=none,domain=-1:1,samples=100]{\k*x};}
\temp


\addplot[color of colormap={\l}, solid, mark=none,domain=-1:1,samples=100]{\k*x};

also it should works without colormaps but with \definecolor?