There are two character sets included with PLplot. These are known as the standard and extended character sets respectively. The standard character set is a subset of the extended set. It contains 177 characters including the ascii characters in a normal style font, the Greek alphabet and several plotter symbols. The extended character set contains almost 1000 characters, including four font styles, and several math, musical and plotter symbols.
The standard character set is loaded into memory automatically when
plstar
or plstart
is called. The extended character set is
loaded by calling plfontld
. The extended character set requires
about 50 KBytes of memory, versus about 5 KBytes for the standard
set. plfontld
can be used to switch between the extended and
standard sets (one set is unloaded before the next is loaded).
plfontld
can be called before plstar
.
When the extended character set is loaded there are four different
font styles to choose from. In this case, the routine plfont
sets
up the default font for all character strings. It may be overridden
for any portion of a string by using an escape sequence within the
text, as described below. This routine has no effect when the
standard font set is loaded. The default font (1) is simple and
fastest to draw; the others are useful for presentation plots on a
high-resolution device.
The font codes are interpreted as follows:
font = 1: normal simple font
font = 2: roman font
font = 3: italic font
font = 4: script font
The routine plschr
is used to set up the size of subsequent
characters drawn. The actual height of a character is the product of
the default character size and a scaling factor. If no call is made
to plschr
, the default character size is set up depending on the
number of subpages defined in the call to plstar
or plstart
, and
the scale is set to 1.0. Under normal circumstances, it is
recommended that the user does not alter the default height, but
simply use the scale parameter. This can be done by calling plschr
with def = 0.0 and scale set to
the desired multiple of the default height. If the default height is
to be changed, def is set to the new default
height in millimeters, and the new character height is again set to
def multiplied by scale.
The routine plssym
sets up the size of all subsequent symbols drawn
by calls to plpoin
and plsym
. It operates analogously to
plschr
as described above.
The lengths of major and minor ticks on the axes are set up by the
routines plsmaj
and plsmin
.