# tikz array indexing to paint with custom palette

I have a custom palette which I want to paint with it by indexing.

Here is my attempt:

\documentclass{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}

\def\colorPallete{{0.00 0.00 0.52, 0.00 0.77 1.00, 1.00 0.98 0.00, 0.73 0.00 0.00}}

\foreach \x [count=\n] in {0,...,3}{%
\definecolor{currentColor}{rgb}{{\colorPallete[\x]}}
\fill [fill=currentColor] (\n,-2) circle[radius=.3];
}
\end{tikzpicture}
\end{document}


The problem is that the parser cannot deal with the rgb triplet, because if I use a similar array indexation to modify some other parameter like int the following example it works.

\documentclass{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}

\def\radiousCollection{{.1, .2, .3, .4}}
\foreach \x [count=\n] in {0,...,3}{%
}
\end{tikzpicture}
\end{document}


A possible workaround is to split the three planes of the color palette into three different arrays then the indexation works as in the case of the radious.

\documentclass{standalone}
\usepackage{tikz}
\begin{document}\tiny
\begin{tikzpicture}

\def\colorPalleteR{{0.00, 0.00, 1.00, 0.73}}
\def\colorPalleteG{{0.00,  0.77,  0.98,  0.00}}
\def\colorPalleteB{{1.0,  1.00,  0.00,0.00}}

\foreach \x [   count=\n,
evaluate=\x as \myRval using ({\colorPalleteR[\x]}),
evaluate=\x as \myGval using ({\colorPalleteG[\x]}),
evaluate=\x as \myBval using ({\colorPalleteB[\x]}) ] in {0,...,3}{%

\definecolor{MyColor}{rgb}{\myRval,\myGval,\myBval}
\fill [fill=MyColor] (\n,0) circle[radius=.3];
\draw   (\n,.8) node {R=\myRval}
(\n,.6) node {G=\myGval}
(\n,.4) node {B=\myBval};
}
\end{tikzpicture}
\end{document}


Can anyone explain how shall be used in order to parse vectors properly so that there is no need to split the palette by planes?

You can only use the array notation inside of tikz/pgf. definecolor isn't from this package. You may use \pgfmathparse to get around this problem:

\documentclass{standalone}
\usepackage{tikz}

\def\colorPallete{{"0.00 0.00 0.52", "0.00 0.77 1.00", "1.00 0.98 0.00", "0.73 0.00 0.00"}}

\begin{document}
\begin{tikzpicture}
\foreach \x [count=\n] in {0,...,3}{%
\pgfmathparse{\colorPallete[\x]};
\definecolor{currentColor}{rgb}{\pgfmathresult};
\fill [fill=currentColor] (\n,-2) circle[radius=.3];
}
\end{tikzpicture}

\end{document}


• well thats the problem, I can't do that. I have 2k+ shapes to color based on an identifier. – Sik Nov 23 '13 at 23:09
• @Sik Just read the manual again and updated my solution. Hope this is what you are looking for. – someonr Nov 24 '13 at 13:56
• You are asking me to parse all my data and instead of using a list of ids, I use a list of colors or something like a { id1/rval1 gval1 bval1, id2/rval2 rgval2 bval2, ... idn/rvalN gvalN bvalN} and yes it is definitlly a work around, but a bad one. Because you are forced to iterate over the colors itsef. If I want to change the palette I've to change the array I'm iterating. – Sik Nov 24 '13 at 18:17
• The only justification to do such a thing would be if the problem I'm posting is related to this tex.stackexchange.com/questions/43226/… – Sik Nov 24 '13 at 18:18
• @Sik Ok, I think that I now understand the question. Are you OK with "0.00 0.00 0.52"? I'm updating the answer. – someonr Nov 24 '13 at 19:03