Does some one know how to create a specific kind of block on Beamer?

Question

I would like to create a block in Beamer exactly as the one illustrated below. Does someone know how to do it?

Answer 1

I don't know which fonts do you use and I made the example for pdflatex so, you'll have to adapt to xetex. But the box is quite similar to the one you want. It's made with tcolorbox.

\documentclass{beamer}
\usetheme{Madrid}
\usepackage{tcolorbox}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[french]{babel}
\usepackage{lmodern}
\tcbuselibrary{skins}

\newtcolorbox{myblock}[1]{
    enhanced,
    frame hidden, interior hidden, segmentation hidden,
    coltitle=black,
    fonttitle=\bfseries\rmfamily,
    fontupper=\tiny,
    title={#1},
    overlay unbroken={\draw[gray,line width=1pt] (frame.north west) rectangle (frame.south east);
    \draw[gray,line width=1pt] ([xshift=5mm]interior.north west)--([xshift=-5mm]interior.north east);
    \shade (frame.south west)--++(0,-1mm)--(frame.south)--cycle;
    \shade (frame.south east)--++(0,-1mm)--(frame.south)--cycle;}
    }

\begin{document}
\begin{frame}{A nice box for beamer}

\begin{myblock}{Oups, nous avons rencontré une erreur.}
Note partagée non trouvée

L'URL fornie ne correspond pas à une note partagée valide. Cela a pu être causé par une erreur typographique dans le lien, ou le propiétaire l'a privaisée.
\end{myblock}
\end{frame}
\end{document}

2nd version

tcolorboxes width is textwidth by default, you can change its size, but if you want to use boxes adjusted to their contents, you need tcboxes.

tcbox width is determined by its text width, if title is longer than text then it's automatically wrapped. \newtcbox creates a command, while \newtcolorbox defines a new environment.

Next code shows how to adapt previous box to be used as tcbox. Previous box is slightly modified, now it uses 2 parameters being the first one optional. It can be used to modify some of default style parameters, like margins. And because margins can change, also middle line is drawn according default or changed margins.

\documentclass{beamer}
\usetheme{Madrid}
\usepackage{tcolorbox}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[french]{babel}
\usepackage{lmodern}
\tcbuselibrary{skins}

\makeatletter
\newtcolorbox{myblock}[2][]{
    enhanced,
    frame hidden, interior hidden, segmentation hidden,
    coltitle=black,
    fonttitle=\bfseries\rmfamily,
    fontupper=\tiny,
    title={#2},
    overlay unbroken={\draw[gray,line width=1pt] (frame.north west) rectangle (frame.south east);
    \draw[gray,line width=1pt] ([xshift=\kvtcb@lefttitle+\kvtcb@boxsep]interior.north west)--([xshift=-(\kvtcb@righttitle+\kvtcb@boxsep)]interior.north east);
    \shade (frame.south west)--++(0,-1mm)--(frame.south)--cycle;
    \shade (frame.south east)--++(0,-1mm)--(frame.south)--cycle;},
    #1
    }

\newtcbox{mybox}[2][]{
      enhanced,
      frame hidden, interior hidden, segmentation hidden,
    coltitle=black,
    fonttitle=\bfseries\rmfamily,
    fontupper=\tiny,
    title={#2},
    overlay unbroken={\draw[gray,line width=1pt] (frame.north west) rectangle (frame.south east);
    \draw[gray,line width=1pt] ([xshift=\kvtcb@lefttitle+\kvtcb@boxsep]interior.north west)--([xshift=-(\kvtcb@righttitle+\kvtcb@boxsep)]interior.north east);
    \shade (frame.south west)--++(0,-1mm)--(frame.south)--cycle;
    \shade (frame.south east)--++(0,-1mm)--(frame.south)--cycle;},
    #1
    }
\makeatother

\begin{document}
\begin{frame}{A nice box for beamer}

\begin{myblock}{Oups, nous avons rencontré une erreur.}
Note partagée non trouvée

L'URL fornie ne correspond pas à une note partagée valide. Cela a pu être causé par une erreur typographique dans le lien, ou le propiétaire l'a privaisée.
\end{myblock}

\mybox{Oups, this is a long title}{Note partagée non trouvée}
\mybox[left=0mm,right=1cm]{Oups}{Note partagée non trouvée}
\end{frame}
\end{document}

Note Since tcolorbox 3.05 lifted shadows are possible as a tcolorbox option. Some examples are shown in Lifted or curved drop shadow