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Formatting information: Chapter 6 — Other document structures

Formatting information

A beginner's introduction to typesetting with LATEX

Chapter 6 — Other document structures

Peter Flynn

Silmaril Consultants
Textual Therapy Division


v. 3.6 (March 2005)

Contents

Introduction
Foreword
Preface
  1. Installing TEX and LATEX
  2. Using your editor to create documents
  3. Basic document structures
  4. Typesetting, viewing and printing
  5. CTAN, packages, and online help
  6. Other document structures
  7. Textual tools
  8. Fonts and layouts
  9. Programmability (macros)
  10. Compatibility with other systems
  1. Configuring TEX search paths
  2. TEX Users Group membership
  3. The ASCII character set
  4. GNU Free Documentation License
References
Index

This edition of Formatting Information was prompted by the generous help I have received from TEX users too numerous to mention individually. Shortly after TUGboat published the November 2003 edition, I was reminded by a spate of email of the fragility of documentation for a system like LATEX which is constantly under development. There have been revisions to packages; issues of new distributions, new tools, and new interfaces; new books and other new documents; corrections to my own errors; suggestions for rewording; and in one or two cases mild abuse for having omitted package X which the author felt to be indispensable to users. ¶ I am grateful as always to the people who sent me corrections and suggestions for improvement. Please keep them coming: only this way can this book reflect what people want to learn. The same limitation still applies, however: no mathematics, as there are already a dozen or more excellent books on the market — as well as other online documents — dealing with mathematical typesetting in TEX and LATEX in finer and better detail than I am capable of. ¶ The structure remains the same, but I have revised and rephrased a lot of material, especially in the earlier chapters where a new user cannot be expected yet to have acquired any depth of knowledge. Many of the screenshots have been updated, and most of the examples and code fragments have been retested. ¶ As I was finishing this edition, I was asked to review an article for The PracTEX Journal, which grew out of the Practical TEX Conference in 2004. The author specifically took the writers of documentation to task for failing to explain things more clearly, and as I read more, I found myself agreeing, and resolving to clear up some specific problems areas as far as possible. It is very difficult for people who write technical documentation to remember how they struggled to learn what has now become a familiar system. So much of what we do is second nature, and a lot of it actually has nothing to do with the software, but more with the way in which we view and approach information, and the general level of knowledge of computing. If I have obscured something by making unreasonable assumptions about your knowledge, please let me know so that I can correct it.

Peter Flynn is author of The HTML Handbook and Understanding SGML and XML Tools, and editor of The XML FAQ.

CHAPTER
6

 

Other document structures

 

  1. A little think about structure
  2. Lists
  3. Tables
  4. Figures
  5. Images
  6. Verbatim text
  7. Boxes, sidebars, and panels
ToC

It is perfectly possible to write whole documents using nothing but section headings and paragraphs. As mentioned in section 3.5, novels, for example, usually consist just of chapters divided into paragraphs. However, it's more common to need other features as well, especially if the document is technical in nature or complex in structure.

It's worth pointing out that ‘technical’ doesn't necessarily mean ‘computer technical’ or ‘engineering technical’: it just means it contains a lot of τηχνε (tekne), the specialist material or artistry of its field. A literary analysis such as La Textualisation de Madame Bovary (on the marginal notes in the manuscripts of Flaubert's novel) is every bit as technical in the literary or linguistic field as the maintenance manual for the Airbus 380 is in the aircraft engineering field.

This chapter covers the most common features needed in writing structured documents: lists, tables, figures (including images), sidebars like boxes and panels, and verbatim text (computer program listings). In Chapter 7 we will cover footnotes, cross-references, citations, and other textual tools.

ToC6.1 A little think about structure

It's very easy to sit down at a keyboard with a traditional wordprocessor and just start typing. If it's a very short document, or something transient or relatively unimportant, then you just want to type it in and make it look ‘right’ by highlighting with the mouse and clicking on font styles and sizes.

In doing so, you may achieve the effect you wanted, but your actions have left no trace behind of why you made these changes. This is usually unimportant for trivial or short-term documents, but if you write longer or more complex documents, or if you often write documents to a regular pattern, then making them consistent by manual methods becomes a nightmare. LATEX's facilities for automation are based on you providing this ‘why’ information.

If your documents have any of the features below, then you have probably already started thinking about structure.

If you've got that far, you're over half-way done. Using a structural editor — even a simple outliner — can make a huge difference to the quality of your thinking because you are consciously organising your thoughts before setting them down. And it can make just as big a difference to your formatting as well: more consistent, better presented, easier for the reader to navigate through, and more likely to be read and understood — which is presumably why you are writing the document in the first place.

ToC6.2 Lists

Lists are useful tools for arranging thoughts in a digestible format, usually a small piece of information at a time. There are four basic types of list, shown in Table 6.1.

Table 6.1Types of lists
Random or arbitrary lists
(sometimes called ‘itemized’ or ‘bulleted’ lists) where the order of items is unimportant. The items are often prefixed with a bullet or other symbol for clarity or decoration, but are sometimes simply left blank, looking like miniature paragraphs (when they are known as ‘simple’ or ‘trivial’ lists).
Enumerated or sequential lists
(sometimes called ‘numbered’ lists) where the order of items is critical, such as sequences of instructions or rankings of importance. The enumeration can be numeric (Arabic or Roman), or lettered (uppercase or lowercase), and can even be programmed to be hierarchical (1.a.viii, 2.3.6, etc.).
Descriptive or labelled lists
(sometimes called ‘discussion’ lists), which are composed of subheadings or topic labels (usually unnumbered but typographically distinct), each followed by one or more indented paragraphs of discussion or explanation.
Inline lists
which are sequential in nature, just like enumerated lists, but are a) formatted within their paragraph; and b) usually labelled with letters, like this example. The items are often mutually inclusive or exclusive, with the final item prefixed by ‘and’ or ‘or’ respectively.

There are actually two other types, segmented lists and reference lists, but these are much rarer, and outside the scope of this document.

The structure of lists in LATEX is identical for each type, but with a different environment name. Lists are another example of this LATEX technique (environments), where a pair of matched commands surrounds some text which needs special treatment.

Within a list environment, list items are always identified by the command \item (followed by an item label in [square brackets] in the case of labelled lists). You don't type the bullet or the number or the formatting, it's all automated.

ToC6.2.1 Itemized lists

To create an itemized list, use the the itemize environment:

\begin{itemize}

\item Itemized lists usually have a bullet;

\item Long items use `hanging indentation', 
whereby the text is wrapped with a margin 
which brings it clear of the bullet used in 
the first line of each item;

\item The bullet can be changed for any other 
symbol, for example from the \textsf{bbding} 
or \textsf{pifont} package.

\end{itemize}
          
  • Itemized lists usually have a bullet;

  • Long items use ‘hanging indentation’, whereby the text is wrapped with a margin which brings it clear of the bullet used in the first line of each item;

  • The bullet can be changed for any other symbol, for example from the bbding or pifont package.

The default list bullet is round and solid1 (舦) which is also available with the command \textbullet if you load the textcomp package. See section 9.6.1 for details of how to change the settings for list item bullets.

  1. If your browser font doesn't show it, don't worry: most don't. LATEX will.

ToC6.2.2 Enumerated lists

To create an enumerated list, use the enumerate environment:

\begin{enumerate}

\item Enumerated lists use numbering on each 
item (can also be letters or roman numerals);

\item Long items use `hanging indentation' 
just the same as for itemized lists;

\item The numbering system can be changed for 
any level.

\end{enumerate}
          
  1. Enumerated lists use numbering on each item (can also be letters or roman numerals);

  2. Long items use ‘hanging indentation’, just the same as for itemized lists;

  3. The numbering system can be changed for any level.

See section 6.2.6 for details of how to change the numbering schemes for each level.

In standard LATEX document classes, the vertical spacing between items, and above and below the lists as a whole, is more than between paragraphs. If you want tightly-packed lists, use the mdwlist package, which provides ‘starred’ versions (itemize*, enumerate*, etc).

ToC6.2.3 Description lists

To create a description list, use the description environment:

\begin{description}

\item[Identification:] description lists 
require a topic for each item given in 
square brackets;

\item[Hanging indentation:] Long items use 
this in the same way as all other lists;

\item[Reformatting:] Long topics can be 
reprogrammed to fold onto multiple lines.

\end{description}
          
Identification:

description lists require a topic for each item given in square brackets;

Hanging indentation:

Long items use this in the same way as all other lists;

Reformatting:

Long topics can be reprogrammed to fold onto multiple lines.

All three of these types of lists can have multiple paragraphs per item: just type the additional paragraphs in the normal way, with a blank line between each. So long as they are still contained within the enclosing environment, they will automatically be indented to follow underneath their item.

ToC6.2.4 Inline lists

Inline lists are a special case as they require the use of the paralist package which provides the inparaenum environment (with an optional formatting specification in square brackets):

\usepackage{paralist}
...
\textbf{\itshape Inline lists}, which are 
sequential in nature, just like enumerated 
lists, but are \begin{inparaenum}[\itshape 
a\upshape)]\item formatted within their 
paragraph; \item usually labelled with 
letters; and \item usually have the final
item prefixed with `and' or 
`or'\end{inparaenum}, like this example. 
          

Inline lists, which are sequential in nature, just like enumerated lists, but are a) formatted within their paragraph; b) usually labelled with letters; and c) usually have the final item prefixed with ‘and’ or ‘or’, like this example.

See Chapter 8 for details of the font-changing commands used in the optional argument to inparaenum.


  Exercise 15. List practice

Add some lists to your document. Pick any two of the ones described here to practice with.

If you successfully installed paralist in the example ‘Install a package’ in section 5.2.2 then you can use inline lists as described in section 6.2.4.


ToC6.2.5 Reference lists and segmented lists

Reference lists are visually indistinguishable from numbered or lettered lists, but the numbering or lettering does not imply a sequence. The numbers or letters are just used as labels so that the items can be referred to from elsewhere in the text (as in ‘see item 501(c)3’). In this sense they are really a kind of sub-sectional division, and LATEX's \paragraph or \subparagraph commands (with appropriate renumbering) would probably be a far better solution than using a list. Label them and refer to them with \label and \ref as for any other cross-reference (see section 7.4).

Segmented lists are a highly specialised structure and outside the scope of this document. For details of their usage, see the the chapter ‘Segmentation and Alignment’ in Guidelines for the Text Encoding Initiative.

ToC6.2.6 Lists within lists

You can start a new list environment within the item of an existing list, so you can embed one list inside another up to four deep. The lists can be of any type, so you can have a description list containing an item in which there is a numbered sub-list, within which there is an item containing a bulleted sub-sub-list.

  1. by default an outer enumerated list is numbered in Arabic numerals;

    1. an embedded enumerated list is lettered in lowercase;

      1. a third level is numbered in lowercase Roman numerals;

        1. the fourth level uses uppercase alphabetic letters.

Multiple embedded lists automatically change the bullet or numbering scheme so that the levels don't get confused, and the spacing between levels is adjusted to become fractionally tighter for more deeply nested levels.

These are only defaults and can easily be changed by redefining the relevant set of values. You could also add a fifth and further levels, although I suspect that would mean your document structure needed some careful analysis, as lists embedded five deep will probably confuse your readers.

The values for lists come in pairs: for each level there is a counter to count the items and a command to produce the label:2

Level Default Counter Label command
1 digit. enumi \theenumi
2 (letter) enumii \theenumii
3 roman. enumiii \theenumiii
4 LETTER. enumiv \theenumiv

Note that each counter and command ends with the Roman numeral value of its level (this is to overcome the rule that LATEX commands can only be made of letters — digits wouldn't work here). To change the format of a numbered list item counter, just renew the meaning of its label:

\renewcommand{\theenumi}{\Alph{enumi}}
\renewcommand{\theenumii}{\roman{enumii}}
\renewcommand{\theenumiii}{\arabic{enumiii}}
        

This would make the outermost list use uppercase letters, the second level use lowercase roman, and the third level use ordinary Arabic numerals. The fourth level would remain unaffected.


  Exercise 16. Nesting

Extend your use of lists by nesting one type inside a different one.


!!!   Lists: a caution to the unwary

Treat lists with care: people sometimes use tables for labelled information which is really a list and would be better handled as such. They often do this because their wordprocessor has no way to do what they want (usually to place the item label level with the description or explanation) except by using a table, hence they are misled into believing that their text is really a table when it's actually not.

  1. In fact, any time you define a counter in LATEX, you automatically get a command to reproduce its value. So if you defined a new counter example to use in a teaching book, by saying \newcounter{example}, that automatically makes available the command \theexample for use when you want to display the current value of example.

ToC6.3 Tables

Tabular typesetting is the most complex and time-consuming of all textual features to get right. This holds true whether you are typing in plain-text form, using a wordprocessor, using LATEX, using HTML or XML, using a DTP system, or some other text-handling package. Fortunately, LATEX provides a table model with a mixture of defaults and configurability to let it produce very high quality tables with a minimum of effort.

!!!   Terminology

LATEX, in common with standard typesetting practice, uses the word ‘Table’ to mean a formal textual feature, numbered and with a caption, referred to from the text (as in ‘See Table 5’). Sometimes you can get ‘informal’ tables, which simply occur between two paragraphs, without caption or number.

The arrangement of information in rows and columns within either of these structures is called a ‘tabulation’ or ‘tabular matter’.

It is important to keep this distinction firmly in mind for this section.

ToC6.3.1 Floats

Tables and Figures are what printers refer to as ‘floats’. This means they are not part of the normal stream of text, but separate entities, positioned in a part of the page to themselves (top, middle, bottom, left, right, or wherever the designer specifies). They always have a caption describing them and they are always numbered so they can be referred to from elsewhere in the text.

LATEX automatically floats Tables and Figures, depending on how much space is left on the page at the point that they are processed. If there is not enough room on the current page, the float is moved to the top of the next page. This can be changed by moving the Table or Figure definition to an earlier or later point in the text, or by adjusting some of the parameters which control automatic floating.

Authors sometimes have many floats occurring in rapid succession, which raises the problem of how they are supposed to fit on the page and still leave room for text. In this case, LATEX stacks them all up and prints them together if possible, or leaves them to the end of the chapter in protest. The skill is to space them out within your text so that they intrude neither on the thread of your argument or discussion, nor on the visual balance of the typeset pages. But this is a skill few authors have, and it's one point at which professional typographic advice or manual intervention may be needed.

There is a float package which lets you create new classes of floating object (perhaps Examples or Exercises).

ToC6.3.2 Formal tables

To create a LATEX Table, use the table environment containing a \caption command where you type the caption, and a \label command to give the Table a label by which you can refer to it.

\begin{table}
\caption{Project expenditure to year-end 2006}
\label{ye2006exp}
...
\end{table}
        

Numbering is automatic, but the \label command must follow the \caption command, not precede it. The numbering automatically includes the chapter number in document classes where this is appropriate (but this can of course be overridden). The \caption command has an optional argument to provide a short caption if the full caption would be too long for the List of Tables:

\caption[Something short]{Some very long caption that 
will only look reasonable in the full figure.}
        

ToC6.3.3 Tabular matter

Within a Table, you can either typeset the tabular matter using LATEX, or include a table captured as an image from elsewhere. We will see how to include images in section 6.4 on Figures, where they are more common.

To typeset tabular matter, use the tabular environment. The \begin{tabular} command must be followed by a compulsory second argument in curly braces giving the alignment of the columns. These are specified for each column using one of single letters l, c, and r for left-aligned, centered, or right-aligned text, or the letter p followed by a width argument if you want a long entry to wrap to several lines (a miniature paragraph as a single cell on each row).

TEX's original tabular settings were designed for classical numerical tabulations, where each cell contains a single value. The p specification allows a cell to be a miniature paragraph set to a specific width. These are p column specifications are not multi-row entries, they are single cells which contain multiple lines of typesetting: the distinction is very important. Auto-adjusting space between columns is possible with the tabularx package, but the auto-resizing column widths used in web pages are not available in LATEX.

The array package provides for many other typographic variations such as left-aligned, right-aligned, and centred multi-line columns, and other packages provide decimal-aligned columns, row-spanning and column-spanning, multi-page, and rotated (landscape format) tables.

Table 6.1Project expenditure to year-end 2006
Item € Amount
a) Salaries (2 research assistants) 28,000
Conference fees and travel expenses 14,228
Computer equipment (5 workstations) 17,493
Software 3,562
b) Rent, light, heat, etc. 1,500
Total 64,783

The Institute also contributes to (a) and (b).

As an example, a tabular setting with three columns, the first one centered, the second left-aligned, and the third one right-aligned, would therefore be specified as {clr}, as in the example below. Note the use of indentation to make the elements of the table clear for editing, and note also how the typeset formatting is unaffected by this (see Table 6.1).

\begin{table}
  \caption{Project expenditure to year-end 2006}
  \label{ye2006exp}
  \begin{center}
    \begin{tabular}{clr}
      &Item&\EUR\ Amount\\
    \hline
      a)&Salaries (2 research assistants)&28,000\\
      &Conference fees and travel expenses&14,228\\
      &Computer equipment (5 workstations)&17,493\\
      &Software&3,562\\
      b)&Rent, light, heat, etc.&1,500\\\cline{3-3}
      &Total&64,783
    \end{tabular}
    \par\medskip\footnotesize
The Institute also contributes to (a) and (b).
  \end{center}
\end{table}
          

You do not need to format the tabular data in your editor: LATEX does this for you when it typesets the table, using the column specifications you provided. Extra space is automatically added between columns, and can be adjusted by changing the \tabcolsep dimension. Takaaki Ota provides an excellent Tables mode for Emacs which provides a spreadsheet-like interface and can generate LATEX table source code (see Figure 6.1).


Figure 6.1Tables mode for Emacs

It is conventional to centre the tabular setting within the Table, using the center environment (note US spelling) or the \centering command. The entries for each cell are separated by an ampersand character (&) and the end of a row is marked by the double-backslash (\\).

The \hline command draws a rule across all columns and the \cline command draws a rule across a range of columns (here, under column three only — the argument needs a range). If used, these commands follow the \\ of the row they apply to. There are some extra formatting commands after the tabular material in the example. These are explained in Chapter 8.

If there is no data for a cell, just don't type anything — but you still need the & separating it from the next column's data. The astute reader will already have deduced that for a table of n columns, there must always be n−1 ampersands in each row. The exception to this is when the \multicolumn command is used to create cells which span multiple columns. There is also a package (multirow) to enable cells to span multiple rows, but both of these techniques are outside the scope of this document.

ToC6.3.4 Tabular techniques for alignment

As mentioned earlier, it's also perfectly possible to typeset tabular matter outside a formal Table, where you want to lay out an informal tabulation between paragraphs where a fully floating formal Table would be unnecessary (these are usually quite short: there are several of them in this document).

Tabular mode can also be used wherever you need to align material side by side, such as in designing letterheads, where you may want your company logo and address on one side and some other information on the other.

By default, LATEX typesets tabular environments inline to the surrounding text, so if you want your alignment displayed by itself, put it inside a positioning environment like center, flushright, or flushleft, or leave a blank line or \par before and after so it gets typeset separately.

There is much more to tabular setting: full details are in the manuals mentioned in the last paragraph in the Foreword. One final note to remind you of the automated crossreferencing features: because the example table is labelled, it can be referenced from anywhere in the document as Table 6.1 just by using \ref{ye2006exp}, regardless of how much the surrounding document or structure is moved or edited.


  Exercise 17. Create a tabulation

Create one of the following in your document:

  • a formal Table with a caption showing the number of people in your class broken down by age and sex;

  • an informal tabulation showing the price for three products;

  • the logo \setlength{\fboxsep}{-3pt}\setlength{\fboxrule}{.4pt} \fbox{\begin{tabular}{cc}\tiny YEAR\\[-.8em]\tiny 2 0 0 0\vrule depth1em width0pt\end{tabular}} (hint: section 6.7.2)


ToC6.4 Figures

As explained in section 6.3.1, Figures and Tables float to a vacant part of the page, as they are not part of the sequence of sentences making up your text, but illustrative objects that you refer to.

Figures can contain text, diagrams, pictures, or any other kind of illustration. To create a figure, use the figure environment: like Tables, they automatically get numbered, and must include a caption (with a label after the caption, if needed, exactly the same as for Tables)

\begin{figure}
\caption{Total variable overhead variance (after 
         \citeauthor[p.191]{bull}}
\label{workeff}
\begin{center}
\includegraphics[width=.75\columnwidth]{diagram}
\end{center}
\end{figure}
      

Figure 6.1Total variable overhead variance (after Bull (1972) p.191)

You can see that the structure is very similar to the table environment, but in this case we have a graphic included. Details of this command (\includegraphics) are in the next section. Details of the bibliographic citation mechanism are in section 7.4.2

The content of the Figure could of course also be textual, in the form of a list or a text diagram. LATEX has a simple drawing environment called picture, which lets you create a limited set of lines and curves, but for a diagram of any complexity, you should use a standard vector drawing program (see section 6.5.1).

ToC6.5 Images

Images (graphics) can be included anywhere in a LATEX document, although in most cases of formal documents they will occur in Figures (see preceding section). To use graphics, you need to use the graphicx package in your preamble: \usepackage{graphicx}3

This enables the command \includegraphics which is used to insert an image in the document. The command is followed by the name of your graphics file without the filetype, for example: \includegraphics{myhouse} (we'll see in a minute why you don't include the filetype).

In most cases you should just make sure the image file is in the same folder (directory) as the document you use it in. This avoids a lot of messing around remembering where you put the files. If you have images you want to use in several different documents in different places on your disk, there is a way to tell LATEX where to look (see section 6.5.2).

For standard LATEX with dvips, graphics files must be in Encapsulated PostScript (EPS) format: this has been the publishing industry standard for portable graphics for many years, and no other format will work portably in standard LATEX.4

All good graphics packages can save images as EPS, but be very careful because some packages, especially on Microsoft Windows platforms, use a very poor quality driver, which creates very poor quality EPS files. If in doubt, check with an expert. If you find an EPS graphic doesn't print, the chances are it's been badly made by the graphics software. Download Adobe's own PostScript driver from their Web site instead.

For pdfLATEX, graphics files can be in Portable Network Graphic (PNG), Joint Photographic Experts Group (JPG), or PDF format, not EPS. This means if you want to use both standard LATEX as well as pdfLATEX, you need to keep your graphics in two formats, EPS and one of the others. This is why you don't include the filetype in the filename you give with \includegraphics: LATEX will assume EPS and pdfLATEX will look for JPG, PNG or PDF files matching the name.

The \includegraphics command can take optional arguments within square brackets before the filename to specify either the height or width, and the other dimension will automatically change to scale. If you specify both, the image will be distorted to fit. You can scale an image by a factor instead of specifying height or width; clip it to specified coordinates; and rotate it in either direction. Multiple optional arguments are separated with commas.

\begin{center}
\includegraphics[width=3cm]{twithcat}
\end{center}
      

For details of all the arguments, see the documentation on the graphicx package or a copy of the The LATEX Companion. This package also includes commands to \raisebox{1ex}{\rotatebox{180}{rotate}}, \scalebox{-1}[1]{mirror}, and \scalebox{2}[1]{scale} text.

It is in fact possible to tell LATEX to generate the right file format by itself, but this requires an external command-line graphics converter, and as it gets done afresh each time, it slows things down rather a lot.

EPS files, especially bitmaps, can be very large indeed, because they are stored in ASCII format. Staszek Wawrykiewicz has drawn my attention to a useful MS-DOS program to overcome this, called cep (‘Compressed Encapsulated Postscript’) available from CTAN in the support/pstools directory, which can compress EPS files to a fraction of their original size. The original file can be replaced by the new smaller version and still used directly with \includegraphics.

  1. You may find a lot of old files which use a package called epsf. Don't use it. It's obsolete.
  1. Some distributions of TEX systems allow other formats to be used, such as PNG, Microsoft Bitmap (BMP) files, Hewlett-Packard's Printer Control Language (PCL) files, and others; but you cannot send such documents to other LATEX users and expect them to work if they don't have the same distribution installed as you have. Stick to EPS.

ToC6.5.1 Making images

There are two types of image: bitmaps and vectors.

Bitmaps

Bitmap images are made of coloured dots, so if you enlarge them, they go jagged at the edges, and if you shrink them, they go blurry. Bitmaps are fine for photographs, where every dot is a different colour, and no-one will notice if you don't shrink or enlarge too much. Bitmaps for diagrams and drawings, however, are almost always the wrong choice, and often disastrously bad.

Vectors

Vector drawings are made from instructions (eg ‘draw this from here to here, using a line this thick’). They can be enlarged or shrunk as much as you like, and never lose accuracy, because they get redrawn automatically at any size. You can't do photographs as vectors, but it's the only acceptable method for drawings or diagrams.

Vector graphic packages are also better suited for saving your image directly in EPS or PDF format (both of which use vectors internally). All the major graphics-generating packages in all disciplines output vector formats: AutoCAD, ChemDraw, MathCAD, Maple, Mathematica, ArcInfo, and so on. EPS is the universally-accepted format for creating vector graphics for publication, with PDF a close second. Most of the major graphics (drawing) packages can also save as EPS, such as PhotoShop, PaintShop Pro, Adobe Illustrator, Corel Draw, and GIMP. There are also some free vector plotting and diagramming packages available like tkPaint and GNUplot which do the same. Never, ever (except in the direst necessity) save any diagram as a bitmap.


Figure 6.1The diagram from Figure 6.1 shrunk and enlarged
 

Bitmap formats like JPG and PNG are ideal for photographs, as they are also able to compress the data substantially without too much loss of quality. However, compressed formats are bad for screenshots, if you are documenting computer tasks, because too much compression makes them blurry. The popular Graphics Interchange Format (GIF) is good for screenshots, but is not supported by TEX: use PNG instead, with the compression turned down to minimum. Avoid uncompressible formats like BMP as they produce enormous and unmanageable files. The Tagged Image File Format (TIFF), popular with graphic designers, should also be avoided because far too many companies have designed and implemented non-standard, conflicting, proprietary extensions to the format, making it virtually useless for transfer between different types of computers (except in faxes, where it's still used in a much stricter version).


  Exercise 18. Adding pictures

Add \usepackage{graphicx} to the preamble of your document, and copy or download an image you want to include. Make sure it is a JPG, PNG, or PDF image if you use pdfLATEX, or an EPS image if you use standard LATEX.

Add \includegraphics and the filename in curly braces (without the filetype), and process the document and preview or print it.

Make it into a figure following the example in section 6.4.

Be aware that some DVI previewers are not able to display all types of graphics, and some cannot display colour. For best results, use PDF or PostScript preview.


ToC6.5.2 Graphics storage

I mentioned earlier that there was a way to tell LATEX where to look if you had stored images centrally for use in many different documents. The answer is in a command \graphicspath which you supply with an argument giving the name of an additional directory path you want searched when a file uses the \includegraphics command, for example:

\graphicspath{c:\mypict~1\camera}
\graphicspath{/var/lib/images}
\graphicspath{HardDisk:Documents:Reports:Pictures}
	

I've used the ‘safe’ (MS-DOS) form of the Windows My Pictures folder because it's A Bad Idea to use directory names containing spaces (see the panel ‘Picking suitable filenames’ in chapter 4). Using \graphicspath does make your file less portable, though, because file paths tend to be specific both to an operating system and to your computer, like the examples above.

ToC6.6 Verbatim text

If you are documenting computer procedures, you probably need fixed-width type for examples of programming or data input or output. Even if you are writing about completely non-computer topics, you may often want to quote a URI or email address which needs to be typeset specially. It is particularly important in these two examples to avoid hyphenating them if they have to break over a line-end, because the hyphen might be taken by the user as a part of the address.

Standard LATEX includes two features for handling fixed-format text, and there are many more available in packages.

ToC6.6.1 Inline verbatim

To specify a word or phrase as verbatim text in typewriter type within a sentence, use the special command \verb, followed by your piece of text surrounded by any suitable character which does not occur in the text itself. This is a very rare exception to the rule that arguments go in curly braces. I often use the plus sign for this, for example to show a LATEX command, I type \verb+\includegraphics[width=3in]{myhouse}+ in order to display \includegraphics[width=3in]{myhouse}, but sometimes I use the grave accent (backtick or open-quote) or the vertical bar when the phrase already has a plus sign in it, like \verb|\(y=a+2x^2\)| when illustrating the LATEX equation \(y=a+x^2\).

This command has the advantage that it turns off all special characters (see section 2.5) except the one you use as the delimiter, so you can easily quote sequences of characters in any computer syntax without problems. However, LATEX will never break the argument of \verb at a line-end when formatting a paragraph, even if it contains spaces, so if it happens to be long, and falls towards the end of a line, it will stick out into the margin. See section 2.8.2 for more information on line-ends and hyphenation.

The url package avoids this by providing the command \url which works in the same way as \verb, with the argument enclosed in a pair of characters, but performs a hyphenless break at punctuation characters, as in http://www.ucc.ie:8080/cocoon/cc/
docs/siteowner.xml
. It was designed for Web URIs,5 so it understands their syntax and will never break mid-way through an unpunctuated word, only at slashes and full points. Bear in mind, however, that spaces are forbidden in URIs, so using spaces in \url arguments will fail, as will using other non-URI-valid characters.

  1. The original term Uniform Resource Locator (URL) is now strongly deprecated in the Web community in favour of the more accurate Uniform Resource Indicator (URI). For details see http://www.w3.org/Addressing/. Unfortunately the older term still persists, especially in LATEX and XML markup.

ToC6.6.2 Display verbatim

For longer (multiline) chunks of fixed-format text, use the verbatim environment:

\begin{verbatim}
\documentclass[11pt,a4paper,oneside]{report}
\begin{document}

\title{Practical Typesetting}
\author{Peter Flynn\\Silmaril Consultants}
\date{December 2004}
\maketitle

\end{document}
\end{verbatim}
        

Like \verb, this turns off all special characters, so you can include anything at all in the verbatim text except the exact line \end{verbatim}

For more control over formatting, however, I recommend the use of the fancyvrb package, which provides a Verbatim environment (note the capital letter) which lets you draw a rule round the verbatim text, change the font size, and even have typographic effects inside the Verbatim environment. It can also be used in conjunction with the fancybox package (see section 6.7.3), and it can add reference line numbers (useful for chunks of data or programming), and it can even include entire external files.


  Exercise 19. Try some fixed-format text

Add your email address and home page URI using the \verb and \url commands. You'll need to \usepackage{url} for the latter.

If you know some programming, try a few lines enclosed in verbatim and Verbatim environments.


ToC6.7 Boxes, sidebars, and panels

LATEX, like most typesetting systems, works by setting text into boxes. The default box is the width of the current page, and works like an old compositor's galley (tray) from the days of metal type: it accumulates typeset text until it's a bit longer than the specified page height. At this stage LATEX works out how much of it really will fit on a page, snips it off and ships it out to the DVI or PDF file, and puts the rest back into the galley to accumulate towards the following page.

ToC6.7.1 Boxes of text

Because of this ‘box’ model, LATEX can typeset any text into a box of any width wherever on the page you need it.

The simplest command for small amounts of text is \parbox. This command needs two arguments in curly braces: the first is the width you want the text set to, and the second is the text itself, for example:

\parbox{1in}{Please make sure you send in your 
             completed forms by January 1st 
             next year, or the penalty clause 
             2(a) will apply}
          
Please make sure you send in your completed forms by January 1st next year, or the penalty clause 2(a) will apply

The text is typeset to the required width, and the box is extended downwards for as long as is required to fit the text. Note that the baseline of a \parbox is set to the midpoint of the box; that is, if you include a \parbox in mid-sentence, the centre of the box will be lined up with the line of type currently being set. You can specify that it should be the top or bottom by adding an optional t or b in square brackets before the width. For example, \parbox[t]{1in}{...} will produce

Notice that when setting very narrow measures with type that is too large, the spacing may become uneven and there may be too much hyphenation. Either use \raggedright or reduce the type size, or (in extreme cases) reword the text or break each line by hand. It is rare for LATEX to need this: the example above was deliberately chosen to be obtuse as an illustration.

Where the contents is more extensive or more complicated, you can use the minipage environment.

Within this you can use virtually everything that occurs in normal text (e.g. lists, paragraphs, tabulations, etc.) with the exception of floats like tables and figures. The minipage environment has an argument just like \parbox does, and it means the same: the width you want the text set to.

Note that in minipages and \parboxes, the paragraph indentation (\parindent) is reset to zero. If you need to change it, set it inside the minipage or \parbox using the \setlength command (see section 3.6).

\begin{minipage}{3in}
Please make sure you send in your completed 
forms by January 1st next year, or the 
penalty clause 2(a) will apply.
\begin{itemize}
\item Incomplete forms will be returned to 
you unprocessed.
\item Forms must be accompanied by the 
correct fee.
\item There is no appeal. The adjudicators' 
decision is final.
\end{itemize}
\end{minipage}
          

Please make sure you send in your completed forms by January 1st next year, or the penalty clause 2(a) will apply.

  • Incomplete forms will be returned to you unprocessed.

  • Forms must be accompanied by the correct fee.

  • There is no appeal. The adjudicators' decision is final.

There are two other ways of typesetting text to widths other than the normal text width: you can use a one-row, one-cell tabular environment with the p column type specification, or you can use the \vbox command, which is raw TEX, and outside the scope of this document.

ToC6.7.2 Framed boxes

To put a frame round \fbox{some text}, use the \fbox command: \fbox{some text}. This works for a few words in mid-line, but the framed box and its contents won't break over the end of a line. To typeset multiline text in a box, put it in a \parbox, or use a minipage or tabular environment as described above, and enclose the whole thing in a \fbox.

\fbox{\begin{minipage}{3in}
This multiline text is more flexible than 
a tabular setting:
\begin{itemize}
\item it can contain any type of normal 
LATEX typesetting;
\item it can be any specified width;
\item it can even have its own 
footnotes\footnote{Like this}.
\end{itemize}
\end{minipage}}
          

This multiline text is more flexible than a tabular setting:

  • it can contain any type of normal LATEX typesetting;

  • it can be any specified width;

  • it can even have its own footnotes.6

The spacing between text and box is controlled by the value of \fboxsep, and the thickness of the line by \fboxrule. The following values were used above:

\setlength{\fboxsep}{1em}
\setlength{\fboxrule}{2pt}
        

As we saw before, setting justified text in narrow measures will produce poor spacing: either use the \raggedright command, or change the font size, or add explicit extra hyphenation points.

Note the \begin{tabular} and \begin{minipage} commands still need the width specifying: in the case of the \begin{tabular} by the use of the p column type with its width specification, and in the case of \begin{minipage} by the second argument.

\fbox{\begin{tabular}{p{1in}}
Multiline text in a box typeset using 
\textsf{tabular}
\end{tabular}}
          
Multiline text in a box typeset using tabular
  1. Like this.

ToC6.7.3 Sidebars and panels

The fancybox package lets you extend the principle of \fbox with commands to surround text in square, oval (round-cornered), and drop-shadow boxes (e.g. \ovalbox, \shadowbox, etc.: see the documentation for details).

You can create panels of any size with these borders by using the minipage environment to typeset the text inside a special Sbox environment which fancybox defines. The minipage formats the text but the Sbox ‘captures’ it, allowing you to put the frame round it as it prints.

The printed version of this document uses this extensively and there is a useful example shown in section 9.5.


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