HP GKS for OpenVMS
HP GKS for OpenVMS SPD 42.60.09
• Screen dumps
Logical Input Devices
HP GKS supports synchronous and asynchronous input
from the following logical input devices:
Locator Allows the user to select a point on the
display.
Stroke Allows the user to input a series of points
on the display.
Valuator Allows the user to select a real number
from a range of numbers, for example, by
sliding a pointer to a position on a radio
dial.
Choice Allows the user to make a selection, for
example, from a list of choices in a menu.
String Allows the user to input a character
string, for example, as input to a prompt.
Pick Allows the user to select an object that
is visible on the display. The information
returned consists of a segment name, a
pick identifier, and the segment status.
Primitives outside segments cannot be
picked.
Character Fonts and Sets
HP GKS includes a series of stroke-precision character
fonts. These character fonts were digitized by Dr. Allen
V. Hershey of the Naval Surface Weapons Laboratory,
and supplied to Digital Equipment Corporation by the
National Bureau of Standards.
HP GKS also provides text support for the native char-
acter sets of the supported graphical devices.
Language Bindings
HP GKS functions can be accessed by four sets of sub-
routine calls or "bindings," as they are referred to by the
GKS standards. These bindings are:
• A FORTRAN binding that conforms to the ISO (DIS
8806/1) FORTRAN binding to GKS-3D.
• A C binding that conforms to a three-dimensional ex-
tension of theISO (DP 8651/4) C language binding to
GKS.
• GKS3D$, a language-independent, three-dimensional
binding that follows the standard calling conventions
and is callable by many different languages.
• GKS$, a language-independent, two-dimensional
binding that follows the standard calling conventions
and is callable by many different languages.
GKS-3D Metafile
HP GKS provides the capability of reading and writing
sequential files in two formats: the ISO 8805 suggested
GKS-3D Metafile format and the ISO 7942 suggested
two-dimensional GKSM Metafile format. The metafiles
can be used to:
• Save and restore graphical information between ses-
sions in a deviceindependent format
• Transfer graphical information between systems with
compatible versions of HP GKS
• Transfer graphical information between two DIGITAL
GKS applications
• Transfer graphical information from a DEC GKS-3D
application to an HP GKS application
• Store accompanying nongraphical information
HP Document Interchange Format (DDIF) Output
HP GKS provides support for storing two-dimensional
views of three-dimensional objects encoded in DIGITAL
Document Interchange Format (DDIF). Views stored in
DDIF can be processed by applications that conform to
the DIGITAL Compound Document Architecture (CDA).
Computer Graphics Metafile (CGM) Output
HP GKS provides support for storing information using
the Computer Graphics Metafile (CGM), an approved
ANSI standard format (ANSI X3.122-1986). HP GKS
supports CGM output for the following formats:
• Clear Text Encoding - Graphical output data stored
in this format is easily created, viewed, and modi-
fied using a common text editor. This format is also
suitable for transferring graphical output data through
networks that support the transfer of text files only.
• Character Encoding - Graphical output data is typi-
cally stored in this format to reduce the file size. This
format is especially suited to transfers through net-
works that do not support binary transfers.
• Binary Encoding - Graphical output data stored in this
format is very compact and the fastest to read and
write. This format is the least suitable for transmis-
sion over communication lines because all 8 bits in
each byte are meaningful.
Graphics Handlers
HP GKS includes support for a wide variety of graphics
devices provided by HP and other vendors. For devices
that are not supported by HP, users can develop their
own graphics device handlers using the HP GKS device
handler interface.
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