GPS(5G) COMMAND REFERENCE GPS(5G)
NAME
gps - graphical primitive string, format of graphical files
DESCRIPTION
GPS is a format used to store graphical data. Several
routines have been developed to edit and display GPS files
on various devices. Also, higher level graphics programs
such as plot(1g) and vtoc(1g) produce GPS format output
files.
A GPS is composed of five types of graphical data or
primitives.
GPS PRIMITIVES
lines The lines primitive has a variable number of
points from which zero or more connected line
segments are produced. The first point given
produces a move to that location. (A move is a
relocation of the graphic cursor without drawing.)
Successive points produce line segments from the
previous point. Parameters are available to set
color, weight, and style (see below).
arc The arc primitive has a variable number of points
to which a curve is fit. The first point produces
a move to that point. If only two points are
included, a line connecting the points will
result; if three points a circular arc through the
points is drawn; and if more than three, lines
connect the points. (In the future, a spline will
be fit to the points if they number greater than
three.) Parameters are available to set color,
weight, and style.
text The text primitive draws characters. It requires
a single point which locates the center of the
first character to be drawn. Parameters are
color, font, textsize, and textangle.
hardware The hardware primitive draws hardware characters
or gives control commands to a hardware device. A
single point locates the beginning location of the
hardware string.
comment A comment is an integer string that is included in
a GPS file but causes nothing to be displayed.
All GPS files begin with a comment of zero length.
GPS PARAMETERS
color Color is an integer value set for arc, lines, and
Printed 10/17/86 1
GPS(5G) COMMAND REFERENCE GPS(5G)
text primitives.
weight Weight is an integer value set for arc and lines
primitives to indicate line thickness. The value
0 is narrow weight, 1 is bold, and 2 is medium
weight.
style Style is an integer value set for lines and arc
primitives to give one of the five different line
styles that can be drawn on TEKTRONIX 4010 series
storage tubes. They are:
0 solid
1 dotted
2 dot dashed
3 dashed
4 long dashed
font An integer value set for text primitives to
designate the text font to be used in drawing a
character string. (Currently font is expressed as
a four-bit weight value followed by a four-bit
style value.)
textsize Textsize is an integer value used in text
primitives to express the size of the characters
to be drawn. Textsize represents the height of
characters in absolute universe-units and is
stored at one-fifth this value in the size-
orientation (so) word (see below).
textangle Textangle is a signed integer value used in text
primitives to express rotation of the character
string around the beginning point. Textangle is
expressed in degrees from the positive x-axis and
can be a positive or negative value. It is stored
in the size-orientation (so) word as a value
256/360 of it's absolute value.
ORGANIZATION
GPS primitives are organized internally as follows:
lines cw points sw
arc cw points sw
text cw point sw so [string]
hardware cw point [string]
comment cw [string]
cw Cw is the control word and begins all primitives.
It consists of four bits that contain a
primitive-type code and twelve bits that contain
the word-count for that primitive.
Printed 10/17/86 2
GPS(5G) COMMAND REFERENCE GPS(5G)
point(s) Point(s) is one or more pairs of integer
coordinates. Text and hardware primitives only
require a single point. Point(s) are values
within a Cartesian plane or universe having 64K
(-32K to +32K) points on each axis.
sw Sw is the style-word and is used in lines, arc,
and text primitives. For all three, eight bits
contain color information. In arc and lines eight
bits are divided as four bits weight and four bits
style. In the text primitive eight bits of sw
contain the font.
so So is the size-orientation word used in text
primitives. Eight bits contain text size and
eight bits contain text rotation.
string String is a null-terminated character string. If
the string does not end on a word boundary, an
additional null is added to the GPS file to insure
word-boundary alignment.
SEE ALSO
abs(1g), af(1g), bar(1g), bel(1g), bucket(1g), ceil(1g),
cor(1g), cusum(1g), cvrtopt(1g), dtoc(1g), erase(1g),
exp(1g), floor(1g), gamma(1g), gas(1g), gd(1g), ged(1g),
graphics(1g), gtop(1g), hardcopy(1g), hilo(1g), hist(1g),
hpd(1g), intro(1g), label(1g), list(1g), log(1g), lreg(1g),
mean(1g), mod(1g), pair(1g), pd(1g), pie(1g), plot(1g),
point(1g), power(1g), prime(1g), prod(1g), ptog(1g),
qsort(1g), quit(1g), rand(1g), rank(1g), remcom(1g),
root(1g), round(1g), siline(1g), sin(1g), subset(1g),
td(1g), tekset(1g), title(1g), total(1g), ttoc(1g), var(1g),
vtoc(1g), whatis(1g), and yoo(1g).
Printed 10/17/86 3
%%index%%
na:72,95;
de:167,2894;3205,3048;6397,1343;
se:7740,1446;
%%index%%000000000090