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TeX
_________________________________________________________________
o What Is TeX?
o Typesetting Versus Writing
o TeX
# Simple Text Formatting
# Fonts
# Controlling Spacing
# Page Layout
# Using Groups
# Mathematical Symbols
# Using Figures in Your Document
# Macros
o LaTeX An Enhancement of TeX
# Defining a LaTeX Document
# Packages
# Using Special Characters
# Putting Structure into a LaTeX Document
# Adding Other Structural Elements
# Working with Figures and Tables
o VirTeX and IniTeX
o Summary
_________________________________________________________________
19
TeX
This chapter looks at the following topics:
* What TeX is and why you would want to use it
* The differences between typesetting and writing
* The enhanced version of TeX called LaTeX
* What VirTeX and IniTeX are
What Is TeX?
TeX (pronounced tech) is a text formatting system invented by Donald
Knuth. It lets you produce professionally typeset documents by
embedding TeX commands within a normal ASCII text file. This text file
can then be converted to what is known as a DVI (device-independent
file), which can be either previewed on-screen using an X Window
program called xdvi or converted to a printer-specific file format,
such as PostScript, HP LaserJet, or for other popular printers.
TeX is a powerful program in that it enables you to define specific
typesetting commands (such as font size, page size, or space between
lines). It also works as a programming language that enables you to
create macros for defining more abstract units of text such as
documents, headings, and paragraphs. The benefit of these high-level
macros is that they enable you to concentrate on the authoring of a
document, not the typesetting. The key appeal of TeX for engineers and
scientists is that it supports the typesetting of complex mathematical
formulas.
Typesetting Versus Writing
The usefulness of a document can be limited by its appearance.
Consider two documents: one that is well-organized with clearly
defined units of text such as chapters, headings, and paragraphs, and
another that has no paragraph breaks and no space between lines. The
first document is much more appealing to the reader, whereas the
second document is downright painful to read. So, despite the best
efforts of an author to create a magnum opus, or even a recipe for
strawberry jam, the meaning behind the words may get lost in a
typographical abyss.
In book publishing, authors aren't usually responsible for anything
beyond the genius of their words. They usually leave the design and
crafting of the book to a book designer. This person then hands the
design template to page layout technicians. TeX performs this book
design and typesetting role for you, enabling you, the author, to be
your own publisher. It gives you control over the publication of your
own material while still permitting you to concentrate on what you're
supposed to be writing about!
TeX
A TeX file can be created with any Linux text editor such as vi or
Emacs. You can enter text into a file called arkana.tex like this:
Do you suppose that Alfred Hitchcock would have had as successful a directing
career if he did not have the considerable talents of actors Cary Grant and
James Stewart in his most popular films? That's a tough one to answer... \bye
After you have saved your file, use the TeX program to convert it to a
DVI file using this command:
$ tex arkana
The resulting arkana.dvi file that is created contains your text. This
file can be used by different output devices (hence the name) for
viewing or printing. For example, if you want to print your DVI file
to a PostScript printer, convert it to a ps format, and print it using
the dvi2ps utility:
$ dvi2ps arkana.ps | lp
This assumes that the default printer is PostScript-capable. If you
want to just preview how the text looks, use the X application xdvi:
$ xdvi arkana.dvi &
The TeX command also produces a log file entitled arkana.log,
containing any error and warning messages, and other information such
as the number of pages of output. The beauty of all this indirect
representation of TeX output is that the TeX source file and its
resulting DVI are very portable, particularly from Linux to its
ancestor UNIX.
Simple Text Formatting
Most of the work in creating a TeX document is putting in the words
that discuss whatever you're writing about. As shown earlier, it is
fairly simple to create an unadorned TeX file: The only special
command you used was \bye. This command tells the TeX program that it
has reached the end of the document. The \bye command uses one of
several characters that TeX treats with special interest, specifically
the backslash or escape character. Here is the set of special
characters that TeX recognizes: \, {, }, ~, #, $, %, ^, &, and the
space character. The meaning behind these characters will be discussed
as you progress.
One of the main conveniences of TeX is the intelligent way it deals
with text. Words are any sequence of characters separated by
whitespace characters. The number of whitespace characters between
words is immaterial because TeX treats them as one character.
Sentences are recognized by the last word preceding a ., ?, !, or :.
Paragraphs are distinguished by a blank line following a sentence.
Much like the spaces between words, TeX treats excess blank lines as
redundant and ignores them. Thus, the text
How do you compare
these two terrific leading men? James Stewart had that good-natured,
All-American charm mixed
with a surprising element of vulnerability, uncommon
among other major Hollywood actors.
Cary Grant, on the other
hand, was versatile enough to play the villain as well as the suave hero in man
y films.
is formatted by TeX as follows:
How do you compare these two terrific leading men? James Stewart had that good-
natured, All-American charm mixed with a surprising element of vulnerability, u
ncommon among other major Hollywood actors.
Cary Grant, on the other hand, was versatile enough to play the villain as well
as the suave hero in many films.
You can also insert comments into your TeX file using the % character.
Text following a % character is treated as a comment and not made part
of the TeX output. The text
From her% Nothing to do with Hitchcock
% ...nothing at all
e to there
is formatted as
From here to there
TeX has several commands for manipulating paragraphs. The \par command
starts a new paragraph, which has the same effect as inserting a blank
line.
From here \par to there
The preceding line is formatted as follows:
From here
to there
The \noindent command tells TeX not to indent the paragraph:
I grew up on Newcastle Street.
\noindent That was close to Hazlehurst.
This is output as follows:
I grew up on Newcastle Street.
That was close to Hazlehurst.
You can also use the escape character before a space in order to force
the insertion of an extra space:
I think that I need an extra\ \ \ space or two.
I'm sure of it.
This becomes
I think that I need an extra space or two.
I'm sure of it.
Fonts
Fonts are representations of characters that share similar size and
style. The default font that TeX uses is Roman. You can override this
by using the internal names that TeX associates with fonts that are
externally loaded. You can also add new font definitions. The
definitions that TeX knows about by default are: \rm (Roman), \tt
(typewriter), \bf (bold), \sl (slanted), and \it (italic). TeX
continues using whatever font was last specified (including the
default) until it is instructed to do otherwise. Therefore, the text
This is roman, but I think I will switch to \tt typewriter for a while; then ag
ain, maybe \it italic would be nice. Now back to \rm roman.
appears as follows:
This is roman, but I think I will switch to typewriter for a while;
then again, maybe italic would be nice. Now back to Roman.
You can add a font and change its size using a command like this:
\font \fontname=auxiliary font
To use a 12-point roman font, redefine the \rm definition to use the
cmr12 auxiliary font, like this:
\font\rm=cmr12
We are changing from this font \rm to that font.
This formats as follows:
We are changing from this font to that font.
Fonts have up to 256 different symbols including the standard numeric,
uppercase, and lowercase character symbols that you use most
frequently. Symbols that are not represented on a standard keyboard
can be accessed using the \char command. This command uses the integer
that follows it as a character code index into a font's character
table. For example, the text
TeX would interpret \char 37 as a comment symbol
but it would not
care about a \char 43 sign.
is processed by TeX as follows:
TeX would interpret % as a comment symbol but it would not
care about a + sign.
Controlling Spacing
You've seen how you can insert individual extra spaces in TeX files.
Now, let's examine how you can have more control over the spacing of
larger portions of text. TeX has a series of commands that recognize
the following units of measurement:
Unit Meaning
em Approximately the width of the character M, depending on the
font in use
in Inches
pt Points (1 inch equals 72 points)
mm Millimeters (1 inch equals 25.4 millimeters)
These units are used with decimal numbers to specify the amount of
spacing that you need. The \hskip command can insert a horizontal
space on a line, like this:
\tt From here \hskip 0.5in to there
This produces the following output:
From here to there
You can also supply a negative number, which moves the text following
the \hskip command to the left (the negative direction). The \hfil
command distributes horizontal space in a paragraph when space is
available. The interesting thing about the \hfil command is the fact
that TeX inserts one implicitly for each paragraph. Bearing this
detail in mind, you can use this command to flush text left or right,
or center it on a line, like this:
\noindent \hfil Some centered text. \par
This is output as follows:
Some centered text.
The \vskip command can insert a vertical space between paragraphs
using a given unit of measurement (much like \hskip). The command
\vskip 40mm
places a vertical space of 40 millimeters between its preceding and
succeeding paragraphs. TeX also provides vertical skipping commands in
convenient units: \smallskip, \medskip, and \bigskip.
The vertical equivalent of \hfil is the \vfill command, which can
distribute vertical spaces between paragraphs when extra space
(nontext) is available. TeX assumes an implicit \vfill command at the
end of a document.
You can also explicitly add line breaks and page breaks to your
document with the \break command. If this command appears within a
paragraph, TeX inserts a line break. If it appears between paragraphs,
a page break is inserted. Conversely, you can specify points in your
document where you want the text to be kept together and not broken
across lines or pages. This is done by using the \nobreak command.
Page Layout
A page is composed of a header, footer, and body. The header and
footer contain information such as chapter title, section heading, and
page number. The body is where the main information in your document
appears. By changing how this information is ordered in your TeX
document, you are actually designing the look of the finished product.
The \headline and \footline commands both take arguments that specify
their content. The format of these commands is as follows:
\headline={parameters}
The parameters could be a list of things such as a page number command
and an \hfil command:
\headline={\hfil \the\pageno}
\footline={\hfil}
This pair of commands creates a right-justified page number and a
blank footer on each page.
You can change the size of the text box that TeX uses for paragraphs
by using the \hsize command. For instance, the text
\hsize=2in
This text is 2 inches wide but we could choose to make it wider or thinner.
produces the following:
This text is 2 inches wide but we could choose to make it wider or thinner.
Margins can be adjusted inward or outward using the \leftskip and
\rightskip commands, respectively. By providing positive values to
these commands, they move the margin inward, depending on which side
you specify (left or right). As you may expect, negative values have
the opposite effect: They move the margins outward. Indentation is
controlled similarly using the \parindent command.
The \baselineskip and \parskip commands control the regular vertical
spacing between lines and paragraphs, as in the following:
\baselineskip=0.15in
\parskip=0.3in
Baseline refers to the distance between the bottoms of characters
(such as an i) on consecutive lines.
Using Groups
Normally, TeX continues using such things as fonts and text styles
until you explicitly change the format. The grouping features of TeX
enable you to define changes that are local to particular sections of
text. The formatting originally specified is then restored after the
group has been processed.
There are two ways to specify how text is grouped. One is to use the
\begingroup and \endgroup command pair. The other is to use the braces
{ and }. Although both of these perform grouping roles, braces are
also used to specify parameters to commands and, as such, must be used
with care.
As an illustration of the use of groups in TeX, the text
Let's see \begingroup \it how {\bf this grouping stuff} really
works \endgroup, shall we?
produces the following:
Let's see how this grouping stuff really
works, shall we?
You may have noted from the example that, in fact, groups can contain
other groups.
Mathematical Symbols
One of the most powerful features of TeX is its capability to generate
correct mathematical notation for formulas with convenient commands.
This is one of the key reasons behind TeX's popularity among engineers
and scientists.
TeX distinguishes between formulas that must appear within regular
text (inline formulas) and those that must appear on their own line
(displayed formulas). You must use the $ symbol to denote inline
formulas, as in
The equation $2+3=x$ must evaluate to $x=5$.
which is generated as the following:
The equation 2+3=x must evaluate to x=5.
However, displayed formulas are denoted using two consecutive $
symbols, as in
The equation $$2+3=x$$ must evaluate to $$x=5$$.
which produces the following:
The equation
2+3=x
must evaluate to
x=5.
Table 19.1 shows some of the math symbols that TeX can generate, their
associated commands, and their meaning.
Table 19.1. Some of the math symbols that TeX can generate.
Symbol TeX Command Meaning
P \pi Pi
� \sum Sum
{ \{ Open bracket
} \} Close bracket
� \int Integral
� \leq Less than or equal to
� \geq Greater than or equal to
� \neq Not equal to
� \bullet Bullet
_ \ldots Horizontal ellipsis
D \diamond Diamond
D \Delta Delta
TeX uses particular fonts for the formulas it produces. These can be
overridden in the usual fashion, but the changes are applicable only
to letters and digits.
Using Figures in Your Document
Figures that are drawn outside of TeX can be inserted into their own
space. This space "floats." In other words, TeX knows that it must
keep track of the figure space as the text around it is added or
deleted. This flexibility means that you, the writer, need not worry
about exactly where in the document your figures will appear.
To insert a figure that must appear at the top of a page, use the
following command:
\topinsert figure \endinsert
Here, figure can be an external reference or an internal definition.
TeX tries to place the figure at the top of the next page with
sufficient space.
You can also tell TeX that you want a figure to appear on its own page
by using this command:
\pageinsert figure \endinsert
Macros
Macros have made TeX a highly extendible system. They essentially
enable you to create new commands by associating existing commands and
text sequences to a macro name. After they are defined, these macros
can be used in other parts of your document to replace repetitive
pieces of text, or to encapsulate abstract operations.
A macro is defined once, using the following format:
\def macroname {new text}
In this case, macroname is a name or TeX command preceded by a
backslash character. Any reference to this macro name is replaced by
the new text throughout the document. For example, the macro
definition
\def\brg{burger}
Ham\brg, cheese\brg, lim\brg.
is output as follows:
Hamburger, cheeseburger, limburger.
Macros can refer to other macros, as in
\def\tig{a tigger }
\def\wond{a wonderful thing }
\def\pooh{\wond is \tig cause \tig is \wond}
\pooh\par
which produces the following:
a wonderful thing is a tigger cause a tigger is a wonderful thing
______________________________________________________________
NOTE: You must be careful of recursive macro
definitions—macros that refer to their own names within their
definition. Such macro definitions cause TeX to continuously (and
vainly) evaluate the macro, leading to an infinite loop. The
following is an example of this:
\def\itself{\itself}
\itself
______________________________________________________________
TeX macros have the added feature of being able to accept parameters
when expanded, if a list of formal parameters has been specified in
the macro definition. To create a macro using parameters, you would
use this format:
\def macroname (list of formal parameters) {new text}
Here, the list of parameters is specified as #1, #1#2, #1#2#3, and so
on. This is a powerful aspect of macros because it can change the
output of an expanded macro based on the parameter in use. For
example, the code
\def\parm#1{This is the #1 time I'll say this.}
\parm{first}
\parm{second}
\parm{last}
produces the following:
This is the first time I'll say this.
This is the second time I'll say this.
This is the last time I'll say this.
Each parameter that is used must be passed separately by enclosing it
in braces, as in
\def\family#1#2{My #1 is #2.}
\family{wife}{Cindy}
\family{sister}{Sheila}
\family{father}{Myles}
which makes the following output:
My wife is Cindy.
My sister is Sheila.
My father is Myles.
You must specify an appropriate match of parameters in your macro
definition. The macro definition
\def\mistake#1{This is wrong because of #2.}
is incorrect because it refers to a second parameter that is not
specified in the formal parameter list.
Macros can be redefined in your document, but you should be aware that
only the most recent definition will be applied. Also, macros defined
within groups are only valid within the scope of the group.
Macro definitions can be nested within each other, as in the
following:
\def\hey{Hey\def\hey{hey}}
\hey, \hey, \hey.
This has the following output:
Hey, hey, hey.
As with many topics within this book, we have examined only some of
the highlights of TeX. There is much more to learn but, having covered
the basics regarding macros, you can now look at the most popular
extension of TeX, which uses macros to enhance the creation of
documents. This extension is LaTeX.
LaTeX An Enhancement of TeX
LaTeX is a collection of macros that build on the capabilities of TeX
and provide a higher level of abstraction for the creation of
documents. It is essentially a style library that encourages uniform
formatting and typesetting across documents. LaTeX macros shift the
emphasis away from the details of things such as "set text to 8-point
slanted" to concepts that writers identify more readily with, such as
the emphasis of a word or phrase. Thus, LaTeX macros have names that
are more representative of the way writers think when they are
writing.
Because LaTeX is an extension of TeX, you'll find it easy to become
quickly productive in LaTeX, assuming that you have some experience in
TeX. White space and spacing between paragraphs are handled in the
same manner as in TeX. The special characters in TeX are the same in
LaTeX, and comments are denoted using the % character.
The key differences between TeX and LaTeX become apparent as you learn
more about the macros that define the layout of your document in a
convenient fashion.
Defining a LaTeX Document
Every LaTeX document begins with the \documentclass command. The
parameter passed to this command specifies what kind of document you
want to write. The basic document classes are described in Table 19.2.
Table 19.2. Document classes.
Document Class Description
article Used for short reports, reference cards, presentations,
scientific journals, and so on.
book Used for complete books.
report Used for reports having several chapters, theses, and so on.
To create a very basic LaTeX document, simply place some words between
the two commands \begin{document} and \end{document}. The text that
precedes the \begin{document} command is called the preamble, and the
text that comes after is known as the body. So, you can create a very
simple document such as the following:
\documentclass{article}
\begin{document}
What a small document this is.
\end{document}
To process this document (which you will edit in a file called
gloves.tex), use the following command:
% latex gloves
This produces a DVI file and a log file in the same manner used by
TeX. The DVI file can either be converted to PostScript, or viewed
directly using xdvi.
You can specify options with the type of document in the
\documentclass command using the following format:
\documentclass[option]{document class}
These options relate to the physical structure of the document. Some
of the more common ones are listed in Table 19.3.
Table 19.3. \documentclass options.
Option Description
10pt, 11pt, 12pt The default font for the document, which is 10pt if
not otherwise stated.
fleqn Displays formulas as left-justified instead of centered.
leqno Numbers formulas on the left side.
letterpaper, a4 paper The paper size, which is letterpaper by default.
openright, openany Starts the first page of a chapter on the right
side, or on the next available page.
titlepage, notitlepage Does or does not start a new page after the
title.
twocolumn Splits each page into two columns (useful for newsletters).
twoside, oneside Generates double- or single-sided output.
Some of the differences between document classes are encapsulated by
the defaults that they use for the options mentioned. For instance,
articles and reports are single-sided by default, whereas books are
not. Articles do not use the options for title pages and starting
right-sided chapters because they do not understand what a chapter is.
Thus, the document classes in LaTeX are smart enough to do the kind of
layout that you expect for the type of document you need.
Packages
LaTeX also has the \usepackage command, which enables you to extend
the capabilities of LaTeX even further by using an external package of
features. The format is as follows:
\usepackage{package name}
package name can be any of several available packages. For instance,
the doc package is used for the documentation of LaTeX programs, and
the makeidx package provides support for the production of indexes.
You can also control what page styles LaTeX applies to your document
by using the \pagestyle command. Table 19.4 describes the basic page
styles available.
Table 19.4. Page styles.
Style Description
empty Sets the header and footers to be empty.
headings Prints the current chapter heading and page number on each
page with an empty footer.
plain Prints the page number centered in the footer (the default page
style).
You can also vary page styles in your document using the
\thispagestyle command. This applies the supplied page style to the
current page only.
Using Special Characters
LaTeX supports the use of international characters, such as umlauts
(_) and circumflexes (^). These characters are generated using a
command variant on the letter itself. For example, the text
What a na\"\i ve ma^itre d' you are!
produces the following:
What a na飗e ma^itre d' you are!
International spacing can also be applied using the \frenchspacing
command. This command tells LaTeX not to insert the usual extra space
after a period.
Putting Structure into a LaTeX Document
LaTeX has commands that make it easy to enhance your document
structurally, thus making it easier for the reader to digest. For the
article document class, the commands are as follows: \section,
\subsection, \subsubsection, \paragraph, \subparagraph, and \appendix.
These commands, with the exception of \appendix, accept titles as
arguments, and are declared before the body of text that they
represent. LaTeX takes care of the rest; it sets the appropriate
spacing between sections, section numbering, and title font. The
\appendix command uses alphabetic increments in order to number
succeeding appendix sections.
For the report and book classes, there are two additional commands:
\part and \chapter. The \part command enables you to insert a section
without affecting the numbering sequence of the chapters. You can
suppress the appearance of a section in the table of contents by
inserting a * character in the section command, as in the following:
\section*{I don't want to know about it}
You probably want to add a title to your document. This is done by
specifying the arguments to the title commands and then calling the
\maketitle command:
...
\title{Confessions of a LaTeX Enthusiast}
\author{Me}
\date
\begin{document}
\maketitle
...
To insert a table of contents in your document, issue the
\tableofcontents command (big surprise) at the point where you want
the table to appear. When you process your document with LaTeX, it
needs two passes: one to make note of all the section numbers, and the
other to build the table of contents from the information it collected
in the first pass.
Adding Other Structural Elements
You can add cross-references to your document, which tie associated
elements such as text, figures, and tables to text in other parts of
your document. Use the \label command to set a point that you want to
refer to, and give it an argument that is any name you choose. This
name can then be referred to by the \ref and \pageref commands to
generate a cross-reference containing the section number and page
number that the section title appears on.
You can easily add footnotes using the \footnote command, which
accepts the text of the footnote as an argument.
Structure is also enhanced by controlling the presentation of the text
that appears between section titles. This can be easily managed by
using LaTeX environments. Environments are specified by bounding a
portion of text with \begin and \end commands, and passing an
environment name to each command, as in the following:
\begin{hostileenvironment}
Looks like we're surrounded, said Custer.
\end{hostileenvironment}
LaTeX has many predefined environments for practical applications, as
described in Table 19.5.
Table 19.5. Predefined environments.
Environment Description
center Centers text.
description Used to present descriptive paragraphs.
enumerate Used for numbered or bulleted lists.
flushleft Paragraphs are left-aligned.
flushright Paragraphs are right-aligned.
itemize Used for simple lists.
quote Used to quote single paragraphs.
quotation Used for longer quotes that span several paragraphs.
tabular Typesets tables with optional row and column separators.
verbatim Produces typed text. Useful for representing programming
code, for example.
verse Used to control the linebreaks in poems.
Working with Figures and Tables
LaTeX also supports the variable placement (or "floating") of figures
and tables in a document using the table and figure environments. A
figure could be specified as follows:
\begin{figure}[!hbp]
\makebox[\textwidth]{\framebox[2in]{\rule{Opt}{2in}}}
\end{figure}
The options passed to the \begin{figure} command are placement
specifiers that indicate your preferences for the location of the
figure. LaTeX has to juggle the placement of floating figures and
tables in a document by using these preferences, as well as internal
guidelines such as the maximum number of floats allowed per page. In
this example, you told LaTeX to keep the figure with its adjacent text
(h), at the bottom of the next applicable page , or, failing that, on
a special page with other floating figures (p). The ! character
overrides LaTeX's best intentions for placing the figure, which may
not necessarily jibe with what you are saying with the other placement
specifiers.
Tables and figures can be labeled using the \caption command, which
must be issued within the table or figure environment.
These are just some of the basics for using LaTeX, but hopefully they
are sufficient to give you a place to start on the road to making your
documents more visually appealing. You have probably noticed that
LaTeX is somewhat easier to work with than TeX itself, because it
hides much detail from you as an author.
VirTeX and IniTeX
Two other TeX-related programs work together but perform slightly
different roles. The IniTeX program is used to create a TeX format
(.fmt) file containing font definitions and macros. The VirTeX program
can then quickly load this precompiled format file, much more quickly
than TeX can. The command to use a format file is as follows:
$ virtex \&myformat sometexfile
The & character is necessary for VirTeX to recognize that it is
loading a format file first; the & must be escaped using the \
character so as not to confuse the shell. The difference between
VirTeX and IniTeX is that VirTeX can't be used to create TeX format
files, but it executes much faster.
Summary
TeX is a document-formatting system for Linux that enables authors to
produce their own high-quality publications. It produces documents
that are portable among output devices such as printers or displays.
TeX supports many typographical features and is particularly
well-suited to the formatting of correct mathematical notation. It has
macros that can be used to enhance the power of its basic command set.
LaTeX, one of the most popular extensions to TeX, uses sophisticated
macros to help you organize and typeset your documents based on its
contents.
--
Enjoy Linux!
-----It's FREE!-----
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