Graphics Options and Device Parameters Dictionary

GPROLOG

Sends a string to device or file before graphics commands are sent.

Used in:	GOPTIONS statement; GDEVICE procedure; GDEVICE Gprolog window
Restriction:	not supported by Java or ActiveX
See also:	PREGPROLOG, POSTGPROLOG

Syntax
Details

Syntax

GPROLOG='string' <...'string-n'>

'string'

can be either of the following:

	'hex-string'X
	'character-string'

In a GOPTIONS statement or in the GDEVICE procedure ADD or MODIFY statement, you can specify multiple strings with the GPROLOG= option. In this case, you can mix the formats, specifying some as ASCII hexadecimal strings and some as character strings. Multiple strings are concatenated automatically.

In the GPROLOG window, enter the hexadecimal string without either quotation marks or a trailing x. Note, however, that the string must be entered as a hexadecimal string.

PROC GOPTIONS always reports the value as a hexadecimal string.

Details

GPROLOG can be used in conjunction with the GEPILOG= graphics option or device parameter.

If you must specify the long and complicated initialization strings required by some devices (for example, PostScript printers), it is easier to use the GOPTIONS GPROLOG= option rather than the GDEVICE Gprolog window because it is easier to code the string as text with GPROLOG= than it is to convert the string to its ASCII representation, which is required to enter the string in the GDEVICE Gprolog window.

Note: On non-ASCII hosts, only ASCII hexadecimal strings produce consistent results in all instances because of the way the character strings are translated. In addition, the only way to specify a value for GEND that can be used by all hosts is to use an ASCII hexadecimal string; therefore, using an ASCII hexadecimal string to specify a value for GEND is the recommended method. [cautionend]

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