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DCL:GRPH1:SGPACK: User Interface:Explanation of Subroutines: Control

2.4.1 SGOPN

1.

Function

Opens a graphics workstation (output device). (Performs initialization).

2.

Call

CALL SGOPN(IWS)

3.

Explanation of Parameters

IWS	(I)	Specifies the workstation number.
		A landscape display when IWS>0,  and  the graphics is displayed as an erect image.
		A portrait display when IWS<0,  and the graphics is displayed as a 90 deg..- rotated image.

4.

Notes

(a)

This is to be called only once before any other GRPH1 subroutine.

(b)

The actual initialization is performed by SGINIT. The SGINIT uses the internal variable 'IWS' to determine the initialization procedure for each device. SGOPN sets the internal variable 'IWS' and executes SGINIT.

(c)

This routine initializes the layout subroutine package  (SLPACK), and sets the workstation viewport on level 1. (See Chapter 4). Therefore, all routines in SLPACK must be called after the SGOPN.

(d)

A list of numbers and names of workstations can be printed out with SGPWSN (See Section 2.4.5). In the standard library, 1: X (X server), 2: PS (postscript), and 3: Tek (Tektronix terminal).