Files of this format are produced by programs such as pixhist3d-plot3(1),
using the routines described in libplot3(3) and are interpreted for
various devices by standard programs described in plot(1G), as well as
additional programs such as plot3-fb(1). The format of output from
libplot3 differs from that of libplot only in the addition of
3-D primitives and color. A graphics file is a stream of plotting
instructions. Each instruction consists of an ASCII letter usually followed by
bytes of binary information. The instructions are executed in order. A point
is designated by four bytes representing the x and y values;
each value is a signed 16-bit integer. These integers are written with the
most significant byte first. Three-dimensional data have an additional
z value, which is assumed to be zero for two-dimensional instructions.
The last designated point in an l, m, n, p,
L, M, N, or P instruction becomes the
"current point" for the next instruction.
Each of the following descriptions begins with the name of the
corresponding routine in libplot3(3).
m
move: The next four bytes give a new current point.
n
cont: Draw a line from the current point to the point
given by the next four bytes. See plot(1G).
p
point: Plot the point given by the next four bytes.
l
line: Draw a line from the point given by the next four
bytes to the point given by the following four bytes.
t
label: Place the following ASCII string so that its first
character falls on the current point. The string is terminated by a
new-line.
a
arc: The first four bytes give the center, the next four
give the starting point, and the last four give the end point of a circular
arc. The least significant coordinate of the end point is used only to
determine the quadrant. The arc is drawn counter-clockwise.
c
circle: The first four bytes give the center of the
circle, the next two the radius. Circles and arcs are not supported on all
devices.
e
erase: Start another frame of output.
f
linmod: Take the following string, up to a new-line, as
the style for drawing further lines. The styles are "dotted",
"solid", "longdashed", "shortdashed", and
"dotdashed". Effective only for the -T4014 and -Tver
options of plot(1G) (TEKTRONIX 4014 terminal and Versatec
plotter).
s
space: The next four bytes give the lower left corner of
the plotting area; the following four give the upper right corner. The plot
will be magnified or reduced to fit the device as closely as possible.
The following were added at BRL. Three-dimensional primitives have
their z values ignored when displayed on two-dimensional devices.
C
color: The next three bytes give respectively the
intensities (0..255) of the three color components (additive colors red,
green, and blue if a terminal; subtractive colors cyan, magenta, and yellow if
hardcopy) to be used for subsequent plotting. The initial color is assumed to
be (255,255,255), which is white on a terminal and black on hardcopy. Color
specifications are ignored for black-and-white devices.
M
3move: The next six bytes give a new current point.
N
3cont: Draw a line from the current point to the point
given by the next six bytes. See plot(1G).
P
3point: Plot the point given by the next six bytes.
L
3line: Draw a line from the point given by the next six
bytes to the point given by the following six bytes.
S
3space: The next six bytes give the minimum corner of the
plotting area; the following six give the maximum corner. The plot will be
magnified or reduced to fit the device as closely as possible.
F
3flush:
x
double_point: The double-precision version of
point.
v
double_line: The double-precision version of line.
o
double_move: The double-precision version of move.
q
double_cont: The double-precision version of cont.
w
double_space: The double-precision version of
space.
i
double_circle: The double-precision version of
circle.
r
double_arc: The double-precision version of arc.
W
double_3space: The double-precision, 3_D version of
space.
X
double_3point: The double-precision, 3_D version of
point.
O
double_3move: The double-precision, 3_D version of
move.
Q
double_3cont: The double-precision, 3_D version of
cont.
V
double_3line: The double-precision, 3_D version of
line.
Space settings that exactly fill the plotting area with unity
scaling appear below for devices supported by the filters of
plot(1G). The upper limit is just outside the plotting area, except
for the Megatek which displays the entire range of possible coordinates. In
every case the plotting area is taken to be square; points outside may be
displayable on devices whose face is not square.
DASI 300
space(0, 0, 4096, 4096);
DASI 300s
space(0, 0, 4096, 4096);
DASI 450
space(0, 0, 4096, 4096);
TEKTRONIX 4014
space(0, 0, 3120, 3120);
Versatec plotter
space(0, 0, 2048, 2048);
Megatek display
space(-32768, -32768, 32767, 32767);
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