randomly color leaders

Question

After reading a bit on random coloring in LaTeX, I had the idea to use randomly colored leaders in a document. I came up with the following piece of code, which was stolen and modified from the \dotfill implementation.

\documentclass{article}

\usepackage{tikz}

\makeatletter
\pgfmathsetseed{1}
\def\qfill{
  \leavevmode \cleaders \hb@xt@ 1em{%
    \hss
    \pgfmathparse{rnd}
    \textcolor[hsb]{\pgfmathresult, 1.0, 1.0}{?}
  }\hfill 
  \kern \z@
}
\makeatother

\begin{document}

\qfill What will be the answer?\qfill

\end{document}

However, it seems that, for one call of qfill, all the question marks will have the same color, with a new color being randomly selected once per call of qfill, and not once for every ?-character (as intended).

What do I need to change in order to have randomly colored leaders?

Answer 1

\documentclass{article}

\usepackage{tikz}

\makeatletter
\pgfmathsetseed{1}
\def\qfill#1{{%
\sbox0{#1}%
\dimen0=1em
\count0=\numexpr\dimexpr(\textwidth-\wd0)/2\relax/\numexpr\dimen0\relax-1\relax
\showthe\count0
\noindent
{\loop
\ifnum\count0>0
\hfil
\hbox to 1em{%
    \hss
    \pgfmathparse{rnd}
    \textcolor[hsb]{\pgfmathresult, 1.0, 1.0}{?}
  }\hfil
\advance\count0 -1
\repeat}%
\box0
{\loop
\ifnum\count0>0
\hfil
\hbox to 1em{%
    \hss
    \pgfmathparse{rnd}
    \textcolor[hsb]{\pgfmathresult, 1.0, 1.0}{?}
  }\hfil
\advance\count0 -1
\repeat}%
\par}}
\makeatother

\begin{document}

\qfill{What will be the answer?}

\end{document}