In
SAS/GRAPH software, translation tables
are most commonly used on an IBM operating environment where tables
are necessary because graphics commands must leave IBM operating environments
in EBCDIC representation but must reach asynchronous graphics devices
in ASCII representation. Specifically,
SAS/GRAPH software builds
the command stream for these devices internally in ASCII representation
but must convert the commands to EBCDIC representation before they
can be given to the communications software for transmission to the
device.
SAS/GRAPH software uses a translation table internally to
make the initial conversion from ASCII to EBCDIC. The communications
software then translates the command stream back to ASCII representation
before it reaches the graphics device.
Translation tables are
operating environment-specific. In most cases, you can simply use
the default translation table, SASGTAB0, or one of the SAS supplied
graphics translation tables. However, if these tables are not able
to do all of the translation correctly, you can create your own translation
table with PROC TRANTAB. The SASGTAB0 table might fail to do the
translation correctly when it encounters characters from languages
other than U.S. English.
To specify an alternative
translation table for
SAS/GRAPH software, you can either use the TRANTAB=
option in a GOPTIONS statement or modify the TRANTAB device parameter
in the device entry. For example, the following GOPTIONS statement
specifies the GTABTCAM graphics translation table:
goptions trantab=gtabtcam;
Translation tables used
in
SAS/GRAPH software perform both device-to-operating
environment translation
and operating environment-to-device
translation. Therefore, a translation table consists of 512 bytes,
with the first 256 bytes used to perform device-to-operating environment
translation (ASCII to EBCDIC on IBM mainframes) and the second 256
bytes used to perform operating environment-to-device translation
(EBCDIC to ASCII on IBM mainframes). For PROC TRANTAB, the area of
a translation table for device-to-operating environment translation
is considered to be table
one, and the area for
operating environment-to-device translation is considered to be table
two. See
Viewing a Translation Table for a listing of the ASCII translation table (a SAS provided
translation table), which shows both areas of the table.
On operating environments
other than IBM mainframes, translation tables can be used to translate
specific characters in the data stream that are created by the driver.
For example, if the driver normally generates a vertical bar in the
data stream, but you want another character to be generated in place
of the vertical bar, you can create a translation table that translates
the vertical bar to an alternate character.
For details about how
to specify translation tables with the TRANTAB= option in
SAS/GRAPH
software, see
SAS/GRAPH
Software: Reference, Version 6, First Edition, Volume 1
and Volume 2.
SAS/GRAPH software also
uses key maps and device maps to map codes generated by the keyboard
to specified characters and to map character codes to codes required
by the graphics output device. These maps are specific to
SAS/GRAPH
software. For more information, contact SAS Institute’s Technical
Support Division.