How to define a random number with xcolor and tikz/pgf

Question

I tried to get a random color with xcolor and tikz:

\documentclass{article}
\usepackage[xetex, rgb]{xcolor}
\usepackage{tikz}

\begin{document}

\pgfmathsetseed{1}
\begin{tikzpicture}
    \xdefinecolor{MyColor}{hsb}{rand, 1.0, 1.0}
    \node[fill=MyColor]{Hello};
\end{tikzpicture}
\end{document}

But this does not work, it reports the following error

Missing number, treated as zero

Does anybody know how to get random colors? thanks.

Answer 1

\begin{tikzpicture}
    \pgfmathparse{rnd}
    \xdefinecolor{MyColor}{hsb}{\pgfmathresult, 1.0, 1.0}
    \node[fill=MyColor]{Hello};
\end{tikzpicture}

Answer 2

The egre solution gives you a Pseudorandom color.

If you use pdftex or one of his son, I suggest you this solution, where for every compilation you will obtain a different color.

\documentclass{standalone}

\usepackage{tikz}


\begin{document}
\begin{tikzpicture}
    \pgfmathparse{rnd}
    \xdefinecolor{MyColor}{rgb}{\pgfmathresult, 1.0, 1.0}
    \node[fill=MyColor](A) at (0,0){Hello};

     \edef\R{\pdfuniformdeviate 255}
     \edef\G{\pdfuniformdeviate 255}
     \edef\B{\pdfuniformdeviate 255}
     \xdefinecolor{MyColor2}{RGB}{\R,\G,\B}
     \node[fill=MyColor2](A2) at (0,-.5){Hello};
\end{tikzpicture}
\end{document}