PLplot can draw graphs consisting of points with optional error bars,
line segments or histograms. Functions which perform each of these
actions may be called after setting up the plotting environment using
plenv
. All of the following functions draw within the box defined
by plenv
, and any lines crossing the boundary are clipped.
Functions are also provided for drawing surface and contour
representations of multidimensional functions. See Chapter 3 for discussion of finer control of plot
generation.
plpoin
and plsym
mark out n points
(x[i], y[i]) with the specified symbol. The
routines differ only in the interpretation of the symbol codes.
plpoin
uses an extended ASCII representation, with the printable
ASCII codes mapping to the respective characters in the current
font, and the codes from 0–31 mapping to various useful
symbols. In plsym
however, the code is a Hershey font code
number. Example programs are provided which display each of the
symbols available using these routines.

PLplot provides two functions for drawing line graphs. All lines are drawn in the currently selected color, style and width. See the Section called Setting Line Attributes in Chapter 3 for information about changing these parameters.
plline
draws a line or curve. The curve consists of
n1 line segments joining the n
points in the input arrays. For single line segments, pljoin
is
used to join two points.


plptex
allows text to be written within the limits set by plenv
.
The reference point of a text string may be located anywhere along an
imaginary horizontal line passing through the string at half the
height of a capital letter. The parameter
just
specifies where along this line the
reference point is located. The string is then rotated about the
reference point through an angle specified by the parameters
dx
and dy
, so that the
string becomes parallel to a line joining (x, y)
to (x+dx, y+dy).

Area fills are done in the currently selected color, line style, line width and pattern style.
plfill
fills a polygon. The polygon consists of
n vertices which define the polygon.

Functions plbin
and plhist
are provided for drawing histograms,
and functions plerrx
and plerry
draw error bars about specified
points. There are lots more too (see Chapter 19).