GPS(5,F) AIX Technical Reference GPS(5,F)
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gps
PURPOSE
Used as the format for storing graphics file data as graphic primitive strings.
DESCRIPTION
A graphic primitive string (GPS) is used to store graphical data in a
particular format. The plot and vtoc commands produce GPS output files.
Several commands edit and display GPS files on various devices. A GPS file is
composed of as many as five types of graphical data or primitives:
comment A comment primitive is an integer string included within a GPS file
that does not cause anything to be displayed. All GPS files begin
with a comment of zero length.
lines A 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, relocating the graphics cursor
without drawing. Successive points produce line segments from the
previous point.
arc An 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 given, a line connecting the points is the result. If
three points are given, a circular arc through the points is drawn.
If more than three points are given, splines are fitted to connect
the points.
text The text primitive draws characters beginning at a given point, with
the first character centered on that point.
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.
Graphic primitive strings are given as 16-bit units called command words. The
first command word determines the primitive type and sets the length of the
string. Subsequent command words contain information in multiples of four bits
of data. The following are the types of GPS and their parameters:
comment cw [string]
cw is the control word. The first four bits identify the comment
primitive and have the value 0xF. The following bits give the
command word count for the primitive.
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GPS(5,F) AIX Technical Reference GPS(5,F)
[string] is a string of characters terminated by a null character.
If the string does not end on a command word boundary, another null
character is added to align the string with the command word
boundary.
lines cw points sw
cw is the control word. The first four bits identify the lines
primitive and have the value 0x0. The remaining bits give the
command word count for the primitive.
points is one or more pairs of integer coordinates having values
within a Cartesian plane or universe of 65,536 points on each axis
(-32,768 to +32,767).
sw is the style command word. The first eight bits hold an integer
value for color information. The next four bits contain an integer
value for weight to indicate line thickness:
0 Narrow
1 Bold
2 Medium.
The last four bits of sw specify an integer value giving line style
information:
0 Solid
1 Dotted
2 Dot-dashed
3 Dashed
4 Long dashed.
arc cw points sw
cw is the control word. The first four bits identify the arc
primitive and have the value 0x3. The next twelve bits contain the
command word count for the primitive.
points is one or more pairs of integer coordinates having values
within a Cartesian plane or universe of 65,536 points on each axis
(-32,768 to +32,767).
sw is the style command word. The first eight bits are an integer
value for color. The next four bits contain an integer value for
weight to indicate line thickness:
0 Narrow
1 Bold
2 Medium.
The last four bits contain an integer value setting line style:
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GPS(5,F) AIX Technical Reference GPS(5,F)
0 Solid
1 Dotted
2 Dot-dashed
3 Dashed
4 Long dashed.
text cw point fw so [string]
cw is the control word. The first four bits identify the text
primitive and have the value 0x2. The remaining twelve bits contain
the command word count for the primitive.
point is a pair of integer coordinates that are a value within a
Cartesian plane or universe of 65,536 points per axis (-32,768 to
+32,767).
fw is a font command word. The first eight bits contain an integer
value for color information. The next eight bits contain an integer
value for font information, with four bits giving the weight
(density) value for the font, and four bits giving the style
(typeface) value for the font.
so is a size/orientation command word. Eight bits specify textsize
as an integer value to indicate the size of characters drawn.
textsize represents character height in absolute universe units. The
actual character height is five times the textsize value. The next
eight bits are a signed integer value for textangle, and express the
angle and direction of rotation of the character string around the
beginning point. textangle is expressed in degrees from the positive
x axis. The textangle value is 256/360 of its absolute value.
hardware cw point [string]
cw is the control word. The first four bits identify the hardware
primitive and have the value 0x4. The next twelve bits indicate the
command word count for the primitive.
point is a pair of integer coordinates that are values within a
Cartesian plane or universe of 65,536 points on each axis (-32,768 to
+32,767). This point is the starting point for the string, which is
a string of hardware characters or control commands to a hardware
device.
RELATED INFORMATION
In this book: "stat.h."
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