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6.1 NCSA Telnet
Tektronix 4014 Graphics 6.1
National Center for Supercomputing Applications
June 1991
6.1 NCSA Telnet
Tektronix 4014 Graphics 6.1
National Center for Supercomputing Applications
June 1991
6/30/91
Chapter 6 Tektronix 4014 Graphics
Chapter Overview
Emulating a Tektronix 4014 Graphics Terminal
Initializing A Plotter
Setting the Configuration File
Switching to and from Graphics Mode
Graphics Mode
Text Mode
Using the Graphics Menu (ALT-G)
Writing Graphics Files to Disk
Renaming Graphics Output Files
Setting the Viewing Region (Zoom Factor)
Redrawing Last Image
Plotting a Stored File
Chapter Overview
NCSA Telnet can emulate the Tektronix 4014 graphics terminal.
This emulation includes text modes, Tek 4014 text sizing, zoom,
pan, and multiple output devices. It supports CGA, EGA, Hercules,
and the Number Nine Revolution 512 x 8 video systems, with the
capability to write out images in PostScript, HPGL, or Tek
drawing commands. The use of Tektronix graphics with NCSA
Telnet depends upon host programs that can produce graphic
images. When these programs run and produce Tektronix 4014
graphics commands, NCSA Telnet automatically switches into
graphics mode and does the drawing.
This chapter describes steps in preparing to emulate the Tektronix
4014 and how to use the Graphics menu.
Emulating a Tektronix 4014 Graphics Terminal
Initializing a Plotter
If you will be plotting directly to a plotter, the communications port
for the plotter must be initialized before you run NCSA Telnet. To
do so, use the DOS mode command. See the DOS manual and the
plotter manual for examples.
Setting the Configuration
File
You'll use NCSA Telnet's configuration file to install the
hardware and software configuration for Tektronix graphics.
There are several settings you should insert in the configuration
file, detailed in Chapter 7, "Installation and Configuration,"
before you use Tektronix emulation.
1. Include tek=yes in the configuration file to enable graphics
operation.
2. Specify the video type with the video parameter in the
configuration file. This is the only step required for selecting
the video display because all of the screen drivers are included
in NCSA Telnet.
3. Install specific filenames to be used when writing each of the
three different kinds of drawing commands. The hpfile
parameter selects the file to receive HPGL commands, the
psfile option selects the file to receive PostScript drawing
commands, and the tekfile option selects the file to receive
Tektronix drawing commands. If you do not make any settings
here, the default files are hp.out, ps.out, and tek.out.
If you want HPGL output to go directly to a plotter that is connected
to COM1 rather than to a disk file:
4. Add hpfile=com1 to your configuration file. Note that you use
COM1 without a colon.
Switching to and from Graphics Mode
Graphics Mode
When host programs produce Tektronix 4014 graphics commands,
NCSA Telnet automatically switches into graphics mode and does
the drawing. The exact command sequence which causes the
switch to graphics mode is the Tektronix clear screen command,
ESC-FF, which is sometimes written as ESC-CTRL-L. A copy of
your text screen is saved while you are in graphics mode.
The second way to enter graphics mode is to press CTRL-HOME.
This key switches from text mode to graphics mode and clears the
graphics screen. Host programs that produce Tektronix 4014
graphics commands cause the screen to automatically go to
graphics mode, so you will not usually need to use CTRL-HOME to
switch to graphics manually.
The third method of starting graphics mode is to re-display the last
graphics image. The re-display option is from the Graphics menu,
described later in this chapter. At the completion of the re-display
command, the screen remains in graphics mode.
Text Mode
To return to text mode, press HOME. When you are in graphics
mode, HOME will set your display back to text mode and redraw
the text screen which was visible before the graphics mode began.
No host command exists which automatically returns to text mode.
When you are in text mode, HOME has a different function.
Using the Graphics Menu (ALT-G)
You display the Graphics menu by pressing ALT-G. Figure 6.1
shows the Graphics menu, as it appears with the default filenames.
You can change the fields in bold.
Figure 6.1 Graphics Menu
ALT-G Graphics menu
< Press the appropriate function key or ESC to
resume >
F1 - Write postscript to a file called: ps.out
F2 - Change postscript output file name
F3 - Write HPGL code to a file called: hp.out
F4 - Change HPGL output file name
F5 - Write Tektronix 4014 codes to a file called: tek.out
F6 - Change Tektronix output file name
View region is currently: 0,0,4095,3119
F7 - Set a new view region (Zoom, Pan)
RETURN - draw picture on screen in current zoom factor
Enter choice:
From this menu, you press the appropriate function key, or
RETURN to redraw the most recently displayed graphics picture.
Writing Graphics Files to
Disk
To write out graphics images, use the Graphics menu. First, you
should display the image on the screen using host software that
generates Tektronix images. NCSA Telnet always keeps the last
graphic image in memory. Select one of the options which writes
this image to disk. The program writes images using the current
view region.
If you select Tektronix 4014 format, NCSA Telnet writes the image
directly to disk and then returns you to your current session. After
selecting the HPGL or the PostScript option from the Graphics
menu, you are returned to your session while the file is written to
disk in the background. After this image has been completely
copied from memory to disk, a message on the console screen tells
you that the process has completed.
Renaming Graphics Output
Files
If you did not set up alternate files to use in the configuration file
and you do not want to use the default filenames hp.out, ps.out, or
tek.out, you can change the names before or after writing the file.
Use the Graphics menu options to change one of the current file
names before writing the image to disk. If you want a name
changed after writing out the file, use ALT-E to escape to DOS, then
use the DOS rename command. Use exit to leave DOS and return
to NCSA Telnet.
A special feature allows you to append the current image to an
existing disk file instead of overwriting. Enter any of the three file
names as you would normally, adding a plus (+) to the beginning
of the name. NCSA Telnet takes the plus (+) to indicate that you
want to open that file for "append", adding another image to the
file. A filename which does not begin with a plus (+), causes NCSA
Telnet to overwrite the file when saving each image.
Setting the Viewing Region
(Zoom Factor)
Another Graphics menu choice lets you set the viewing region, or
zoom factor. Any portion of the image can be enlarged and made to
fill the screen. Tektronix drawing commands are resolved to a
4096 x 3120 pixel resolution. Values start with 0,0 in the lower left,
and go to 4095, 3119 in the upper right.
The default view region for NCSA Telnet is (0, 0, 4095, 3119), which
is the full image. Figure 6.1 has examples of possible viewing
regions that you can use.
Figure 6.2 Sample Viewing
Regions
Redrawing Last Image
Use the Graphics menu option, Redraw Last Image, is used when
you want to review the image that is currently in memory. This
option always zooms and enlarges the image according to the view
region that is visible. The selected view region always fills the
screen so you can see more detail.
This command leaves you in graphics mode, so press HOME if you
want to return to text mode.
Plotting a Stored File
If you have used the Graphics menu to store a file of HPGL drawing
commands, the DOS copy command can send those commands to
an attached plotter (which is connected to COM1 in this example).
C:> copy filename.out com1