I managed to add in the TOC the string Chapter x before each chapter title (following this post).
The chapter titles format was :
A Nice Title
They are now :
Chapter 1 A Nice Title
Everything works great.
But, in a second step, how do I proceed to add it in the bookmarks displayed by the PDF viewers ? Even more, how do I add it only for those include in the \mainmatter part ?
Info : I use xelatex.
[EDIT]
Here is a MWE :
\documentclass[a4paper,oneside]{book}
\usepackage{lipsum}
\usepackage{hyperref}
\usepackage{titletoc}
\titlecontents*{chapter}
[0pt]% <left>
{}
{\chaptername\ \thecontentslabel\quad}
{}
{\bfseries\hfill\contentspage}
\title{My document}
\begin{document}
\frontmatter
\chapter{Introduction} \lipsum[1]
\section{First section} \lipsum[2-3]
\section{Second section} \lipsum[4-5]
\section{Last section} \lipsum[6-7]
\mainmatter
\chapter{Second chapter} \lipsum[1]
\section{First section} \lipsum[2-3]
\section{Second section} \lipsum[4-5]
\section{Last section} \lipsum[6-7]
\chapter{Last chapter} \lipsum[1]
\section{First section} \lipsum[2-3]
\section{Second section} \lipsum[4-5]
\section{Last section} \lipsum[6-7]
\backmatter
\chapter{Conclusion}
\lipsum[8]
\tableofcontents
\end{document}
What gives :
I'd like the same format for the chapters titles in the PDF bookmarks. It seems that a solution could be found with the bookmark package... but it's a mystery to me.


hyperrefoptionbookmarknumbered. I would not add the prefixChapter. Mostly the bookmarks are displayed in a narrow side bar. A long non-informative prefix just removes the informative title beyond the right margin. – Heiko Oberdiek Mar 07 '18 at 19:25