# Getting the right paper geometry from (La)TeX

If your output is the wrong size, and you’ve checked that it’s not due to the ministrations of Adobe Reader, the problem is probably that your (La)TeX system is producing output that specifies the wrong paper size. Paper sizes can be a pain: they’re a forgotten backwater — Knuth seems not to have considered paper size as something the TeX engine needs to know about. As a result, there is no DVI command to specify the paper on which the document should be printed, which has led a dichotomy where macros shape the text according to the needs of the author’s chosen paper size, and device drivers’ choice happens independently of the macros’ ideas.

In practice, one usually finds that macro packages (such as Plain TeX and LaTeX) assume American “letter” paper size, by default; and since most distributions nowadays originate in Europe, the drivers usually default to ISO “A4” paper size.

This is (of course) pretty unsatisfactory. Users may select a different paper size for their document (current LaTeX offers a range of sizes as options in the standard classes), pretty easily. Nevertheless, the user also has to be sure that each time xdvi, dvips (or whatever) runs, it uses the paper size the document was designed for.

The default paper size for DVI drivers may be changed by a distribution management command (texconfig for texlive, the Options application for MiKTeX), but this still doesn’t provide for people using the “wrong” sort of paper for some reason.

A different issue arises for users of PDFTeX — the PDF format does have the means of expressing paper size and PDFTeX has system variables `\pdfpagewidth` and `\pdfpageheight`, that are written into the output PDF file. Unfortunately, most of the core software predates PDFTeX, so not even PDFLaTeX sets the correct values into those variables, to match the paper size specified in a `\documentclass` option.

The DVI drivers dvips, dvipdfm and its extensions (dvipdfmx and xdvipdfmx) define `\special` commands for the document to specify its own paper size; so in those cases, as when PDFTeX is being used, the paper size can be programmed by the document. Users who wish to, may of course consult the manuals of the various programs to write the necessary code.

The geometry and zwpagelayout packages (whose main business includes defining typeset page areas), also takes notice the size of the paper that the document is going to be printed on, and can issue the commands necessary to ensure the correct size of paper is used. If geometry is used when a document is being processed by PDFLaTeX, it can set the necessary dimensions “in the output”. If the document is being processed by LaTeX on a TeX or e-TeX engine, there are package options which instruct geometry which `\special` commands to use. (Note that the options are ignored if you are using PDFLaTeX.)

So, one resolution of the problem, when you are using LaTeX, is to add

```\usepackage[processor-option,...]{geometry}
```
Where `processor-option` tells the package what will produce your (PostScript or PDF output — geometry knows about `dvips` and `dvipdfm` (`dvipdfm` also serves for the extension dvipdfmx and xdvipdfmx).

If you’re using PDFLaTeX or XeTeX, load with

```\usepackage[program-option,...]{geometry}
```
where `program-option` is `pdftex`, `xetex`.

The alternative, zwpagelayout requires a `driver` option:

```\usepackage[driver=value,...]{zwpagelayout}
```
(permissible ‹values› are `pdftex`, `xetex` and `dvips`; the default value is `unknown`).

Needless to say, both the “big” classes (koma-script and memoir) provide their own ways to get the paper size “right”.

The typearea package is the Koma-script distribution’s way of providing page layout functionality. Load it with the `pagesize` option and it will ensure the correct paper is selected, for PDF output from PDFLaTeX, and for PostScript output from LaTeX via dvips.

Memoir has the standard classes’ paper-size selections (`a4paper`, `letterpaper` and so on), but also permits the user to choose an arbitrary paper size, by setting the length registers `\stockheight` and `\stockwidth`. The commands `\fixdvipslayout` (for LaTeX processing), and `\fixpdflayout` (for PDFLaTeX processing) then instruct the processor to produce output that specifies the necessary paper size.

geometry.sty
geometry
memoir.cls
memoir
typearea.sty
Distributed as part of koma-script
zwpagelayout.sty
zwpagelayout