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

13.2. Extended pictures 305
The default values for the optional stretch argument in \dashline and
\drawline are initially 0, but may be changed at any time by redefining
(with \renewcommand) \dashlinestretch and \drawlinestretch, respectively.
This makes it possible to revise a whole set of curves with one
command, rather than manually changing each one.
13.2.2 The eepic package
Package: The epic commands are still subject to many of the limitations of the
eepic picture environment: limited number of slopes for lines, limited line
thicknesses, restrictions on circle sizes. This is because the picture
environment uses LAT EX fonts to ‘draw’ inclined lines and circles, making
the results portable to all output devices.
The eepic package, by Conrad Kwok repairs these problems by employing
graphic commands executed by the DVI driver itself. They are
transmitted to the .dvi file by \special commands, which are driverspecific.
Thus greater flexibility is achieved, but at the price of loss
of portability. The package is therefore most suitable for use with the
PostScript dvips driver, as well as with the previewers xdvi and windvi.
It does not work with pdfTEX, unfortunately; on the other hand, it has no
problems with dvipdfm.
However, eepic not only recodes the features of epic, it also adds
some additional functionality. If one wishes to invoke these extra features
with a driver that does not recognize the graphics \specials, one can use
the emulation package eepicemu instead. A comparison of the results
with these two packages is shown in Figure 13.1 on the next page.
In either case, one must load epic with one of eepic or eepicemu:
\usepackage{epic,eepic} or \usepackage{epic,eepicemu}
The following standard picture elements are modified by the eepic
package:
\line(∆x,∆y){length} (page 293) where ∆x and ∆y may take on any
positive or negative integer values, and not just those between ±6.
\circle{diameter} (page 295) may have any value for diameter; the
same for \circle*.
\oval (page 296) may have the maximum diameter of the corners set to
any value; this is stored in the length \maxovaldiam which the user
may change; the default value is 40 pt.
Similarly, all the extra commands from epic package are also revised
internally. The restrictions on slopes never apply directly to them, but
lines of arbitrary slope are drawn with little segments at the nearest
available slope, or as series of dots, requiring much computer time and