# How to modify the total width in a tufte-book using includemp?

I'am working on a tufte-book document class and I want to change the size of the page. As the page are smaller, I want to fix the total width of the text (including the marginal notes). The documentation of the document class specifies using the geometry package.

In the documentation of this package, the width parameter is explained as follows:

width|totalwidth

width of total body. width= or totalwidth=. This dimension defaults to textwidth, but if includemp is set to true, width ≥ textwidth because width includes the width of the marginal notes. If textwidth and width are specified at the same time, textwidth takes priority over width.

This is the text in my preamble :

\documentclass[symmetric,justified,marginals=raggedouter]{tufte-book}
\usepackage{microtype}
\usepackage{calc}
\usepackage{geometry,afterpage}
\geometry{papersize={16.8cm,23.7cm}}% <= it seems to be OK
\geometry{textheight=18.6cm}%text : 132 *186 mm <= it is OK
\geometry{width=13.2cm}% <= The code doesn't take into account the marginparwidth and the marginparsep

\begin{document}

\end{document]


I don't know how to specify that includemp is set to true.

The quotation from the geometry manual says "If textwidth and width are specified at the same time, textwidth takes priority over width".

In the source for tufte-book, specifically the file tufte-common.def, the following code is present:

\RequirePackage[letterpaper,left=1in,top=1in,headsep=2\baselineskip,textwidth=26pc,marginparsep=2pc,marginparwidth=12pc,textheight=44\baselineskip,headheight=\baselineskip]{geometry}


This means that textwidth is specified in the class, and therefore that any width specifications given later (for example in the .tex file) are ignored.

To change the width of the text therefore you need to specify textwidth and take the margin size into account manually. However, arithmetic expressions can be used in \geometry. Therefore the following code

\geometry{textwidth=13.2cm-\marginparwidth-\marginparsep}


specifies that the main text and the margin combined are 13.2cm.