Making a margin figure wider than the margin

Question

I'm using the Tufte class and I want to create a margin figure that is larger than the margin, making the text wrap around it. Any tips of how I might do that? I tried adapting the @tufte@margin@floatbox to get a third argument for the minipage width, but I'm failing miserably. Here's what I got so far:

\newsavebox{\myfloatboxwider}
\newenvironment{myfloatwider}[3][-1.2ex]%
  {\FloatBarrier% process all floats before this point so the figure/table numbers stay in order.
  \begin{lrbox}{\myfloatboxwider}%
  \hspace*{-\marginparwidth}%
  \begin{minipage}{#3}%
    \@tufte@caption@font%
    \def\@captype{#2}%
    \hbox{}\vspace*{#1}%
    \@tufte@caption@justification%
    \@tufte@margin@par%
    \noindent%
  }
  {\end{minipage}%
  \end{lrbox}%
  \marginpar{\usebox{\myfloatboxwider}}%
  }

\newenvironment{marginfigurewider}[2][-1.2ex]%
  {\begin{myfloatwider}[#1]{figure}{#2}}
  {\end{myfloatwider}}

To use like this

\begin{marginfigurewider}[1.2ex]{2.0\marginparwidth}%
  \includegraphics[width=\linewidth]{myimage.jpg}
  \caption{Some caption.}
  \label{fig:somefig}
\end{marginfigurewider}

However there are two problems left that I cannot solve:

1. The hspace should actually be #3-\marginparwidth, but I can't find a way to make this calculation.
2. The main text does not wrap around it. Do I need something like wrapfig for this?

Update

This achieves more or less what I want:

\setlength\columnsep{\marginparsep}
\begin{wrapfigure}{O}[\dimexpr \marginparwidth+\marginparsep]{2.0\marginparwidth}
  \FloatBarrier%
  \vspace{-0.7\baselineskip}
  \begin{minipage}[b]{2.0\marginparwidth}
    \includegraphics[width=\linewidth]{myimage.jpg}
    \caption{Some caption.}
    \label{fig:somefig}
  \end{minipage}
\end{wrapfigure}

There are still two problems:

1. Side notes, like cite, are overlaid over the image, not floated down below it.
2. I can't make it work as a \newenvironment. Nothing shows, and width=\linewidth is flagged as not a number. I can live by using the code manually, but it'd be nicer if it was an environment. Attempt is below:

---

\newenvironment{marginfigurewide}[1]%
  {\FloatBarrier%
  \setlength\columnsep{\marginparsep}%
  \begin{wrapfigure}{O}[\dimexpr \marginparwidth+\marginparsep]{2.0\marginparwidth}%
      \vspace{-0.7\baselineskip}%
      \begin{minipage}[b]{2.0\marginparwidth}
  }
  {\end{minipage}%
  \end{wrapfigure}
  }

Answer 1

I had the bright idea of reserving blank space in the margin using \marginpar. However, wrapfigure will still overlap any pre-existing margin material. I don't know of any way to delay the start of wrapfigure until the margin is empty (except manually).

Also, I don't know why \wrapfigure works and \begin{wrapfigure} doesn't, but it probably has something to do with local vs. global values.

\documentclass{tufte-book}
\usepackage{graphicx}
\usepackage{wrapfig}
\usepackage{marginfix}

\usepackage{lipsum}
\usepackage{showframe}

\newsavebox{\marginbox}

\makeatletter
\newenvironment{marginfigurewide}[1]% #1 = width
{\begin{lrbox}{\marginbox}%
  \def\@captype{figure}%
  \begin{minipage}{#1}}%
{\end{minipage}\end{lrbox}%
  %\setlength{\intextsep}{0pt}%
  \setlength{\columnsep}{\marginparsep}%
  \wrapfigure{r}[\dimexpr \marginparwidth+\marginparsep]{\wd\marginbox}
    \usebox\marginbox
  \endwrapfigure
  \marginpar{\rule{0pt}{\dimexpr \ht\marginbox+\dp\marginbox+2\intextsep}}}% reserve space in margin
\makeatother

\begin{document}

\begin{marginfigurewide}{2\marginparwidth}
  \includegraphics[width=\linewidth]{example-image}
  \caption{Some caption.}
  \label{fig:somefig}
\end{marginfigurewide}

test\sidenote{\LipsumPar{2}}

\LipsumPar{1}

\end{document}

---

The version will overlap the bottom of the page.

\documentclass[twoside]{tufte-book}
\usepackage{graphicx}
\usepackage{wrapfig}
\usepackage{marginfix}

\usepackage{lipsum}
\usepackage{showframe}

\newsavebox{\marginbox}

\makeatletter
\newenvironment{marginfigurewide}[1]% #1 = width
{\begin{lrbox}{\marginbox}%
  \def\@captype{figure}%
  \begin{minipage}{#1}}%
{\end{minipage}\end{lrbox}%
  \setlength{\columnsep}{\marginparsep}%
  \dimen0=\dimexpr \pagegoal-\pagetotal-\ht\strutbox\relax% remaining space on page
  \dimen1=\dimexpr \ht\marginbox+\dp\marginbox+\intextsep\relax% size of figure
  \ifdim\dimen1<\dimen0% fits page
    \wrapfigure{r}[\dimexpr \marginparwidth+\marginparsep]{\wd\marginbox}
      \usebox\marginbox
    \endwrapfigure
    \marginpar{\rule{0pt}{\dimexpr \ht\marginbox+\dp\marginbox+2\intextsep}}% reserve space in margin
  \else% overlaps bottom
    \wrapfigure{r}[\dimexpr \marginparwidth+\marginparsep]{\wd\marginbox}
      \raisebox{\dimexpr \dimen0-\intextsep-\ht\marginbox}[\dimexpr \dimen0-2\intextsep][0pt]{\usebox\marginbox}%
    \endwrapfigure
    \marginpar{\rule{0pt}{\dimen0}}%
  \fi}
\makeatother

\begin{document}

\begin{marginfigurewide}{2\marginparwidth}
  \includegraphics[width=\linewidth]{example-image}
  \caption{Some caption.}
  \label{fig:somefig}
\end{marginfigurewide}

Place note here.\sidenote{\LipsumPar{2}}

%\LipsumPar{1}
\lipsum[1-2]

\begin{marginfigurewide}{2\marginparwidth}
  \includegraphics[width=\linewidth]{example-image}
  \caption{Some caption.}
  \label{fig:somefig}
\end{marginfigurewide}

Place note here.\sidenote{\LipsumPar{2}}

\lipsum[3-4]

\end{document}