by Trent A. Fisher and Werner Lemberg - The GNU Operating System

20 The GNU Troff Manual
3.2.2 Sections and Chapters
Most macro packages supply some form of section headers. The simplest
kind is simply the heading on a line by itself in bold type. Others supply
automatically numbered section heading or different heading styles at different
levels. Some, more sophisticated, macro packages supply macros for
starting chapters and appendices.
3.2.3 Headers and Footers
Every macro package gives some way to manipulate the headers and footers
(also called titles) on each page. This is text put at the top and bottom of
each page, respectively, which contain data like the current page number,
the current chapter title, and so on. Its appearance is not affected by the
running text. Some packages allow for different ones on the even and odd
pages (for material printed in a book form).
The titles are called three-part titles, that is, there is a left-justified
part, a centered part, and a right-justified part. An automatically generated
page number may be put in any of these fields with the ‘%’ character
(see Section 5.15 [Page Layout], page 104, for more details).
3.2.4 Page Layout
Most macro packages let the user specify top and bottom margins and other
details about the appearance of the printed pages.
3.2.5 Displays
Displays are sections of text to be set off from the body of the paper. Major
quotes, tables, and figures are types of displays, as are all the examples used
in this document.
Major quotes are quotes which are several lines long, and hence are set
in from the rest of the text without quote marks around them.
A list is an indented, single-spaced, unfilled display. Lists should be used
when the material to be printed should not be filled and justified like normal
text, such as columns of figures or the examples used in this paper.
A keep is a display of lines which are kept on a single page if possible.
An example for a keep might be a diagram. Keeps differ from lists in that
lists may be broken over a page boundary whereas keeps are not.
Floating keeps move relative to the text. Hence, they are good for things
which are referred to by name, such as “See figure 3”. A floating keep
appears at the bottom of the current page if it fits; otherwise, it appears at
the top of the next page. Meanwhile, the surrounding text ‘flows’ around
the keep, thus leaving no blank areas.
3.2.6 Footnotes and Annotations
There are a number of requests to save text for later printing.