LaTeX — document preparation system

The base program of LaTeX is TeX and was developed by Donald E. Knuth during his time as a computer science professor at Stanford University. Building on TeX, Leslie Lamport developed LaTeX in the early 1980s, a collection of TeX macros that simplified and enhanced its use for the average user compared to TeX. The name LaTeX is an abbreviation for Lamport TeX.

Lamport's development of LaTeX ended around 1990 with version 2.09. The current version LaTeX 2ε was developed from 1989 onwards by a larger number of authors around Frank Mittelbach, Chris Rowley and Rainer Schöpf. Major enhancements of Lamport's versions consisted of a "four-dimensional" mechanism for switching between character sets ("New Font Selection Scheme", "NFSS"), a more complex mechanism for reading in supplementary packages, and a corresponding "package writer interface" for creating and documenting macro packages based on LaTeX. The two development levels of LaTeX are not compatible.

LaTeX 2ε has been the most widely used method of using TeX since the mid-1990s.

No WYSIWYG

In contrast to other word processors, which work according to the what-you-see-is-what-you-get principle, the author works with text files in which he textually marks out passages or headings to be formatted differently within a text with commands. The example below shows the source code of a simple LaTeX document. Before the LaTeX system can set the text accordingly, it must process the source code. The layout generated by LaTeX is considered to be very clean, its formula set very sophisticated. In addition, output to PDF, HTML and PostScript is possible. LaTeX is particularly suitable for extensive works such as theses and dissertations, which often have to meet strict typographical requirements. Especially in mathematics and the natural sciences LaTeX facilitates the preparation of documents by its comfortable possibilities of formula setting compared to usual word processing systems. The process of LaTeX is also paraphrased with WYSIWYAF (What you see is what you asked for. ).

Compared to conventional word processors, working step by step requires a longer training period on the one hand, but on the other hand the appearance of the result can be precisely defined. However, the longer training period can be worthwhile, especially for subsequent projects with a comparable scope or similar requirements. In the meantime, there are also graphical editors that can work with LaTeX and offer WYSIWYG or WYSIWYM (What you see is what you mean. ), which can make it much easier for inexperienced users to get started. Examples of LaTeX development environments are listed in the section Development Environments.

Logical markup

When using LaTeX, a so-called logical markup is used. For example, if a heading is to be created in a document, the text is not highlighted purely visually as in TeX (for example, by using bold with a larger font, thus: \font\meinfont=cmb10 at 24pt \meinfont introduction), but the heading is marked as such (for example, using \section{introduction}). In the class or sty files, it is globally specified how such a section heading is to be designed: "put the whole thing in bold; precede it with a number to be incremented; prepare the entry in the table of contents", etc. This will give all such passages of text a uniform formatting. It also makes it possible to automatically generate a table of contents from all the headings in the document using the \tableofcontents command.

Computer independence

Like TeX itself, LaTeX is largely computer-independent. This means that, analogous to TeX, there are also productive LaTeX installations for most operating systems. These operating systems include Microsoft Windows from version 3.x up to the current version 10, Apple macOS as well as various Linux distributions. Provided that all used additional packages (see below) are installed in suitable versions, the advantage of using LaTeX is that the result is always exactly the same in the two output formats DVI and PDF with regard to fonts and sizes as well as line and page breaks in print, independent of the computer platform and printer used. LaTeX does not depend on the fonts of the respective operating system. Those operating system fonts are often optimized for monitor display. LaTeX contains a number of its own fonts, which are themselves optimized for printing.

Technology, alternatives, development, license

LaTeX forms a "format" in a TeX-specific sense. It consists at its core of a latex.ltx file of macro definitions, which is converted to a memory image latex.fmt after the definitions have been executed. This file is first read by the "engine" (a binary program such as TeX or pdfTeX) for each document generation run. Other important formats are plain TeX and ConTeXt. Compared to these, there are many additional packages for LaTeX - further macro collections - which are based on the macros in latex.ltx and considerably extend the presentation possibilities initially given by the engine and the macros in latex.ltx. Most of them were developed by LaTeX users for their own special needs (publications, teaching material, theses) and then made available to the general public under a mostly free license. Especially for this purpose the LaTeX Project Public License was developed, which also applies to latex.ltx and other packages of the main LaTeX developers. Many such additional packages have also been developed on behalf of publishers, journals, professional societies and universities (for theses) for the implementation of their design guidelines.