Guide to LaTeX (4th Edition) (Tools and Techniques

13
Drawing with LAT E X
The inclusion of graphical material from other programs is treated in
Chapter 6. Such ‘foreign’ files do add some complications (which are
greatly reduced today with L AT E X 2ε) and can cause portability problems.
What would be desirable is a means to do graphics with L AT E X itself so that
the source text file is fully self-contained.
Standard L AT E X does contain the means to make somewhat primitive
drawings on its own. The word ‘primitive’ should not be considered
derogatory, for simple building blocks are the basic units for constructing
very complicated, sophisticated structures. They are also useful for
superimposing imported graphics or for adding embellishments to them,
as demonstrated in Section 6.1.5.
This chapter describes the intrinsic L AT E X drawing capabilities, and then
explains some extensions that are available to enhance them.
Many more possibilities exist for adding specialized diagrams, from
chemistry, to music, to chess positions. These are described in detail in
The L AT E X Graphics Companion by Goossens et al. (1997).
13.1 The picture environment
13.1.1 Picture coordinates
The picture building blocks can only be put in place once a coordinate
system has been established for that picture. This consists of a reference
point or origin, and two mutually perpendicular coordinate axes, as well
as a length unit for the coordinates. The origin is the lower left corner
of the picture and the axes are its lower and left edges. These edges are
referred to as the x-axis (lower) and y-axis (left).
Once the unit of length (UL) has been specified, every point within the
picture area can be uniquely referred to with two decimal numbers: the
first is the number of length units along the x-axis, the second the number
along the y-axis.
287