background framed box with newenvironment "encadre"

Question

I want to use a floating framed box that could be nicely placed in the text. \fbox needs to be placed by hand. I wrote this code which was exactly what I want to get...but with a floating object.

\documentclass[a4paper,12pt]{book}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[francais]{babel}
\usepackage{lipsum}
\usepackage{caption}
\usepackage[usenames,dvipsnames]{color} 
\usepackage{framed}
\usepackage{hyperref} 
\newcounter{encadre}
\newenvironment{encadre}
\refstepcounter{encadre}\vspace{0.2cm}\textsc{\bfseries encadré \theencadre\ :}}
{\par\vspace{0.2cm}}
\begin{document}
\lipsum
\fcolorbox{Black}{Gray}{
\begin{minipage}{\linewidth}
   \begin{encadre}\label{enc:metamere}
blabla
\end{encadre}
\lipsum[10]
\end{minipage}
}
\end{document}

So I use framed (impossible to install mdframed on my LaTeX version of 2009 on Ubuntu 12.04)

My question : Where must I define \defineshadecolor as it is said in the framed documentation?

framed doc p2 :"In fact, the “shaded” environment just redefines \FrameCommand to be \colorbox{shadecolor} (and you have to define the color “shadecolor”: \definecolor{shadecolor}...)."

I tried to put it as an option or to write it like directly in the preamble, but it does not work. Here is the framed code, but without background.

\documentclass[a4paper,12pt]{book}
\usepackage[utf8]{inputenc} \usepackage[T1]{fontenc}
\usepackage[francais]{babel}
\usepackage{lipsum}
\usepackage{caption}
\usepackage{xcolor}
\usepackage{framed}
\usepackage{hyperref}

\newcounter{encadre}
\newenvironment{encadre} {\refstepcounter{encadre}
\vspace{0.3cm}\textsc{\bfseries encadré \theencadre\ :}}
{\par\vspace{0.3cm}}

\begin{document} 
\lipsum [50]

\begin{framed}
 \begin{encadre} test
 \end{encadre}\label{enc}
\lipsum[15]
\end{framed}


l'encadré \ref{enc} est à la page \pageref{enc}

 \lipsum 
\end{document}

Answer 1

Here the solution, thanks a lot to Gonzalo

 \documentclass[a4paper,12pt]{book}
 \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc}
 \usepackage[francais]{babel}
 \usepackage{lipsum, caption, xcolor, framed}
 \definecolor{shadecolor}{RGB}{140,20,21}
 \newcounter{encadre}
 \newenvironment{encadre} {\refstepcounter{encadre}
 \vspace{0.3cm}\textsc{\bfseries encadré \theencadre\ :}}
 {\par\vspace{0.3cm}}

\begin{document} 
\lipsum [50]
\begin{framed}
   \begin{shaded}
      \begin{encadre} test     
      \end{encadre} 
    \lipsum[15]
   \end{shaded}
\end{framed}
\lipsum 
\end{document}

Answer 2

Here and example of "Encadré" box with package tcolorbox. I do not know why, but it needs the package to be in the same folder than the .tex file. It does not work if the tcolorbox.sty is the usual location (for me /usr/share/texmf/tex/latex)

documentclass[a4paper,12pt]{book}
\usepackage[utf8]{inputenc} \usepackage[T1]{fontenc}
\usepackage[francais]{babel}
\usepackage{lipsum, xcolor}
\usepackage{tcolorbox}
\newtcolorbox[auto counter,number within=chapter]{encbox}[2][]{%
colback=blue!5!white,colframe=blue!75!black,fonttitle=\bfseries,
title=Encadré.~\thetcbcounter: #2,#1}
\begin{document} 
\chapter{boite}
\begin{encbox}{Boite tbolorbox}
\lipsum[30]
\end{encbox}
\end{document}