HP GKS for OpenVMS

HP GKS for OpenVMS SPD 42.60.09
PEX Support
HP GKS supports output to the DIGITAL implementa-
tion of PEX Ver- sion 5.0 and PEX Version 5.1 servers.
For OpenVMS Alpha, the PEX server extension and the
PEXlib object library are available as part of the Open3D
for OpenVMS Alpha product.
Output Modes
With HP GKS, you can describe a graphical object us-
ing either segments or immediate mode. A segment is
a set of output primitives that are created, manipulated,
and deleted as a group, but are not modifiable. HP GKS
manages segments internally and automatically redraws
them if the display is damaged (for example, if the dis-
play window is obscured and then exposed).
In immediate mode, primitives are rendered directly to
the display surface without being stored internally in HP
GKS. This mode is useful when graphical data is tem-
porary, or will be refreshed by the application.
Output Primitives
HP GKS provides a variety of output primitives for creat-
ing basic two-dimensional and three-dimensional graph-
ics. These primitives are:
Cell Array A rectangular image specified by a two-
dimensional array of rectangular color
cells on a plane arbitrarily placed in
three-dimensional space.
Fill Area A polygonal area that can be hollow or
filled with a uniform color, a pattern, or a
hatch style. The edges of the area are
not defined and cannot be controlled.
Fill Area Set A set of polygonal areas with holes or
disjointed regions that are treated as a
single entity. These areas can be hollow
or filled with a uniform color, patterns, or
hatch styles. Control of edge attributes is
provided.
Generalized
Drawing Primi-
tive (GDP)
A primitive providing access to drawing
capabilities of graphics devices not used
by the other primitives listed here; circles
and arcs are two common GDPs.
Polyline A set of connected lines defined by a
series of points and having line type, line
width, and color attributes defined.
Polymarker One or more symbols that can mark
significant points in a display and have
type, size, scale, and color attributes
defined.
Text A character string at a given position in
world coordinates. This string can be in
8-bit or 16-bit format, and can be dis-
played in a variety of fonts, orientations,
sizes, and colors. Text size is affected by
transformations.
Attributes
Each output primitive has an associated set of attributes
that control the primitive’s appearance. Attributes can
be defined in groups (bundles) or individually. Some
examples of attributes are:
Line Type The style of a line, for example, dotted or
dashed.
Line Width The width of the line.
Color The color of a primitive. You can select
one of the predefined colors or specify
the red, green, and blue intensities
required to define a particular color on
color devices.
Character At-
tributes
Text attributes, including font, charac-
ter spacing, height, angle, path, and
alignment.
Viewing Operations
HP GKS allows you to specify views of three-
dimensional objects and define the "working" or world
coordinate system used in these views. World coordi-
nates can have any scale. For example, one application
might have a maximum range from 0 to 1000.0; another
application might limit the range from 0.01 to 0.1.
You can control multiple, simultaneous views of the
same objects on one or more display surfaces, as well
as the position and size of the image on the surface. For
example, one application program can display an image
of a cube in one window on a workstation, and at the
same time, the program can display a detail of the back
of the cube in another window (on another workstation,
if required).
Control Functions
Control functions are used to perform system man-
agement tasks related to the HP GKS environment,
the workstation environment, and the graphics display.
These tasks include turning HP GKS on and off when re-
quested by the application, directing the flow of graphics
data to logical output devices and managing the picture
process.
Inquiry Functions
HP GKS includes a complete set of inquiry functions.
These functions are used to obtain information about
the HP GKS state, segment storage, workstation capa-
bilities, or the workstation state. This information is es-
sential for developing modular, device-independent pro-
grams.
Escape Functions
Escape functions are included with HP GKS to enable
access to functionality not provided in the GKS stan-
dard. The HP GKS escape functions include:
• Double buffering control
• Background pixmap control
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