Problem with sidecaption and memoir alignment

Question

I try to use sideCaption with memoir class, and i have two problems (red anotation in image 1) :

• sideCaption doesn't respect the margin at left ...
• how can i say to saidCaption to align the figure name to the top of my figure ?

The minimal code :

\documentclass[a4paper, 12pt,twoside, openright]{memoir}
\usepackage{polyglossia}
\setdefaultlanguage{french}
\usepackage{fontspec}
\usepackage[usenames,dvipsnames]{xcolor}
\usepackage[autostyle=true,french=guillemets,maxlevel=3]{csquotes}
\usepackage{xparse}
\usepackage{graphicx}
\usepackage[protrusion=true]{microtype}

\graphicspath{{FigureIntroduction/}}

\makeatletter
\renewcommand{\fnum@figure}[1]{\textbf{\figurename~\thefigure}}
\makeatother

\begin{document}

\chapterstyle{bringhurst}

\begin{figure}[!h]
\begin{sidecaption}[fortoc]{Le "champignon informationnel" proposé par Frédéric Kaplan est révélateur de l'augmentation du champs d'expérimentation rendu possible par la numérisation des données, puis la simulation numérique.}[fig:I_Champi]
 %\centering
 %\resizebox*{\textwidth}{!}{\includegraphics{champignonKaplan.png}}
 \includegraphics[width=\linewidth]{champignonKaplan.png}
  \end{sidecaption}
\end{figure}

\end{document}

The result :

Answer 1

I would think that you'd rather want the caption in the outer margin, so you could say

\sidecapmargin{outer}

The width of the sidecap is defined by the length \sidecapwidth, which by default is \marginparwidth, so to modify it use \setlength\sidecapwidth{<length of your choice>}. Personally I'd just use the outer margin though.

To fix the alignment, do

\setsidecappos{t}

This is described in section 10.10 Side captions in memoirs manual.

Complete code:

\documentclass[a4paper, 12pt,twoside, openright]{memoir}
\usepackage[demo]{graphicx}
\sidecapmargin{outer}
\setsidecappos{t}
\makeatletter
\renewcommand{\fnum@figure}[1]{\textbf{\figurename~\thefigure:} }
\makeatother
\begin{document}

\begin{figure}
\begin{sidecaption}{Le "champignon informationnel" proposé par Frédéric Kaplan est révélateur de l'augmentation du champs d'expérimentation rendu possible par la numérisation des données, puis la simulation numérique.}[fig:I_Champi]
 %\centering
 %\resizebox*{\textwidth}{!}{\includegraphics{champignonKaplan.png}}
 \includegraphics[width=\linewidth]{champignonKaplan.png}
  \end{sidecaption}
\end{figure}
\end{document}