Interface Usage                               Tektronix 4010 Interface

		       Tektronix 4010 Interface

This interface is suitable for most Tektronix graphics terminals and
emulators, including 4010, 4014, 4107 and 4208.

1. Initialisation of Plotting Device

   NAG uses the subroutine named XXXXXX in all examples programs and
   documentation to represent the initialisation of your chosen
   plotting device. In order to initialise the Tektronix 4010 NAG
   Graphical Interface you must call the supplied routine NAGTEK. If
   you wish this may be incorporated into a subroutine named XXXXXX.

   A template, omitting any initialisation of variables, for routine
   XXXXXX might be:

           SUBROUTINE XXXXXX 
     C
           LOGICAL          PAUSE
           CHARACTER        DEVICE
     C
           CALL NAGTEK(DEVICE,PAUSE)
     C
           RETURN
           END

   where:

   DEVICE - indicates which type of output is to be generated:

            DEVICE = 'T' - output suitable for Tektronix 4010 storage
                           screen device. 
            DEVICE = 'K' - output suitable for devices that accept the
                           non-standard extension provided in
                           MS/PC-Kermit to support colour. 
            DEVICE = 'P' - Output suitable for use with the UNIX
                           `plot' command. 

            If any other string is supplied, output will be generated
            that is suitable for Tektronix emulators such as NCS
            Telnet, xterm, or Rainbow. 

   PAUSE  - indicates whether a prompt should be issued at the end of
            a frame (PAUSE = .TRUE.) or not (PAUSE = .FALSE.).

   Note: the use of a prompt is relevant only in cases where the
   output is directed to the screen, rather than to a file for later
   processing.

   Note: the Tektronix 4010 NAG Graphical Interface directs output
   instructions to the command sequence channel defined by NAG
   Graphics Library utility routine J06VCF.

2. NAG Pens

   The four NAG pens are distinguished by line style and text font.
   They are distinguished by colour only if the target device permits,
   and DEVICE = 'K' was specified at initialisation.

   Default pen settings:

                      Pen 1   Pen 2   Pen 3   Pen 4
     Colour      -- device and initialisation dependent --
     Line Style        1       2       3       4
     Text Font         1       2       3       4

   By default the current pen is pen 1.

   Note: some sites may have chosen to revise the default settings of
   NAG pens; you are referred to local documentation for details.

   Colours

   The number of colours available depends upon your chosen output
   device, and the specification of DEVICE at initialisation:

     DEVICE   Minimum colour index   Maximum colour index
       'K'            0                      14
      other           1                       1

   Line style

   The Tektronix 4010 NAG Graphical Interface offers you a choice of
   eight different line styles.

   Text Fonts

   The Tektronix 4010 NAG Graphical Interface does not offer any
   Tektronix text fonts; Hershey quality text is used in all cases.

   Note: as only one quality of text is available, a call to NAG
   Graphical Interface routine J06XFF will not affect the text
   produced. 

   For details of the Hershey fonts, you are referred to the document
   `Available Hershey fonts'.

   Marker Styles

   Markers are generated directly by the NAG Graphical Interface. A
   choice of 9 marker styles is offered.

   Note: as only one quality of marker is available, a call to NAG
   Graphical Interface routine J06XFF will not affect the markers
   produced. 

   NAG Brushes

   The Tektronix 4010 NAG Graphical Interface offers only the NAG
   simulated area fill styles; calling palette 1 will have no effect.

   Default brush settings:

                                      Brush number
                        1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16
     Colour                -- device and initialisation dependent --
     Fill style             All brushes are defaulted to hatch fill
     Fill index         1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16

   By default the current brush is brush 1 and the current palette is
   NAG simulated fill.

4. Additional Comments

   (a) The Tektronix 4010 NAG Graphical Interface does not support grey
       shades.

   (b) Colours may not be redefined (NAG Graphical Interface routine
       J06XLF).

   (c) Often screen output devices are accessed by directing commands
       from an application using the standard output channel for the
       host machine. In this case you must ensure that you call NAG
       Graphics Library utility routine J06VCF to inform the NAG
       Graphics Library of the appropriate Fortran unit number to use.
       If the standard output channel is not used then any plotting
       commands generated will generally be directed to a file for
       subsequent processing.

       By default the NAG Graphics Library utilises the standard
       output channel to output error messages; as such you should
       ensure that a different unit number is assigned by calling NAG
       Graphics Library utility routine J06VAF. If subsequently you
       use a NAG example program you will need to modify the parameter
       statement NOUT = 6 to reflect the new error message unit
       number.

5. Interface Number

   The value of IFACE output by NAG Graphics Library routine J00AAF
   for the Tektronix 4010 NAG Graphical Interface is:

     IFACE = 31

6. Reference

   [1] 4010 and 4010-1 Users Manual.
       Tektronix Inc., 1972.

===================================================================
    Copyright The Numerical Algorithms Group Ltd, U.K., 1994
    Developed by D.J. Adams of the Computing Services,
                 University of Southampton.