Geometry Package - Layoutoffset: Distinction Between Odd and Even Pages Possible?

Question

Currently I'm preparing a book for publishing. My printer wants a non-circumferential bleed around the pages, 0.125" at the top, bottom and outer side, but no bleed at the inner side. As far as I have seen until now, this is quite unusual, since a circumferential bleed is required normally.

Starting from this standard case, let us assume a book with a width of 7" and a height of 10". A circumferential bleed of 0.125" may easily be added using the geometry package and its papersize, layoutsize and layoutoffset option:

\geometry{papersize={7.25in,10.25in}, layoutsize={7in,10in}, layoutoffset={0.125in,0.125in}, ...}

For the case of a circumferential bleed this will work fine; in addition, no changes to the layout will happen, because the layoutsize is fixed to 7" × 10" (which is the later trim size). My intention is to preserve the later layout of the book, regardless of on what kind of paper size it is printed (paper size > layout size, of course). This is important to me because I need to generate a digital version of the book with exactly identical layout.

But this won't work for a non-circumferential bleed, since — as far as I know — layoutoffset is not able to distinguish between odd and even pages. For each odd (left) page, I would need

\geometry{papersize={7.125in,10.25in}, layoutsize={7in,10in}, layoutoffset={0.125in,0.125in}, ...}

and for every even page:

\geometry{papersize={7.125in,10.25in}, layoutsize={7in,10in}, layoutoffset={0in,0.125in}, ...}

Thus, I would appreciate any help regarding a possibility of modifying the original layoutoffset option of the geometry package to distinguish between odd and even pages — possibly by introducing two new package options layoutoffsetodd and layoutoffseteven to the geometry package (that would be the solution I'm most comfortable with; unfortunetely I'm not able by myself to do that).

Thank you for your help in advance!

Answer 1

Neither geometry nor crop can do what you want, without extensive patching of their inner workings. So I'm afraid that changing the layout parameter is the way to go, but with a negative binding offset, as you want the space in the outer margin:

\usepackage{geometry}
\geometry{
  papersize={7.125in,10.25in},
  layoutsize={6.875in,10in}, % compensate for the negative binding offset
  bindingoffset=-.125in,
  layoutoffset={.125in,0.125in},
}

After all, it's a one time computation and you can then forget about it.

Answer 2

Here's a fairly straightforward solution using memoir.

Note that to keep the answer focussed on the problem, I haven't tried to tune the size of the typeblock itself.

\documentclass[a5paper,showtrims]{memoir} % A5 quick-and-dirty
\usepackage{kantlipsum}      % Only to provide blind text
\setstocksize{10.25in}{7.125in}
\settrimmedsize{10in}{7in}{*}
\settrims{0.125in}{0.125in}
\checkandfixthelayout
\trimXmarks                  % Only to show the trimmings
% =================================================
\begin{document}
% =================================================
\kant[1-8]
% =================================================
\end{document}