## Sunday, 15 February 2009

### Using the LaTeX letter document class

LaTeX offers a variety of built-in document classes. One of them is letter, which is designed for writing official letters, such as the one I just did to the (inept) agency that manages my flat. However, that standard document class is not very well liked: it's the ugly little duckling of the LaTeX document classes. But when you just have to get things done, better the devil you know than the one you don't. So here's a quick summary of easy tweaks I applied to my letter to bend the default document class to my needs.

#### Structure

The letter document class requires a specific structure. It is designed so that you can write several letters to several recipients while using the same return address. The basic structure of a letter document looks something like this:

Basic structure of a letter document
\documentclass{letter}

\begin{document}

\opening{The opening, such as: Dear Sir,}

The body of the letter

\closing{The closing, such as: Best regards,}

\end{letter}
\end{document}


The letter environment that is enclosed in the document environment looks superfluous at first. The idea is that you can have several letter environments when you want to produce more than a single letter: this can be very useful for mailings.

#### Top space

The document class introduces a lot of white space at the top. This is good for a multi-page letter but looks really awkward on a single page letter. So, I did what the TeX FAQ suggests and added the following in the preamble, just after the \documentclass command:

Preamble to remove the initial top space

\makeatletter
\let\@texttop\relax
\makeatother

\begin{document}


As my managing agent specified a reference in the letter they sent me, I wanted to include that reference in my letter, just after their address but with some small vertical space in between. There is no obvious way to do that so I just added it to the end of the recipient's address with a space of length \parskip:

\begin{letter}{The recipient's address\\[\parskip]


#### Adding some vertical space before the closing sentence

The closing sentence is printed very close to the last paragraph in the letter. I wanted a bit more space so added the following just before the \closing command:

\vspace{3\parskip}
\closing{The closing, such as: Best regards,}


#### Adding space between the closing and the signature

When writing a letter, I like leaving enough space between the closing sentence and the printed signature so that I can add a hand written signature once it's printed. The standard space is too small for this. However, considering both lines are printed by the \closing command, there is no obvious way to include any space in between. However, looking at the letter.cls code, it appears that the standard template adds 6 times the \medskipamount length in between the two lines so the simple way to change that space is to change the relevant length just before the \closing command:

Adding between the closing and signature
\vspace{3\parskip}
\closing{The closing, such as: Best regards,}


This will multiply the \medskipamount length by 3 and as result multiply the space between closing and signature by 3 as well. This works great for a single letter but will not have the intended result when you have multiple letters in the same document. The way to avoid this is to save the original length and restore it afterwards:

Adding between the closing and signature
\vspace{3\parskip}
\setlength{\oldmedskipamount}{\medskipamount}