Screen Dump.

[David M. Laur]

In article <8905030950.aa10952 at SMOKE.BRL.MIL>, swenson at NUSC-WPN.ARPA writes:

>        I would like to perform a screen dump from a 4D-60T to a file in
>PostScript format to be sent to an Apple (alias Sun) LaserWriter printer.
>I would like at least 16 (probably dithered) grey levels and the option to
>select seperate windows or the entire screen to be dumped.  Am I in the
>land of fantasy?  I would appreciate any suggestions on this subject.
>Thanks.
>                                Steve Swenson
>                                SWENSON at NUSC-WPN.ARPA


If you get the  "Laser Printer Software Option" and the Transcript
package (from AT&T via SGI), then you can print IRIS/4D screendumps
directly to a PostScript printer using "lp".

Use the program "/usr/sbin/scrsave" to capture some or all of the
current screen into an SGI-format image file, the simply "lp"
the file.  The print spooling software converts the image to
PostScript commands and sends them to the printer.  If you want to
capture the intermediate PS code, you can run the converter manually,
it's called "/usr/lib/print/pprint".

The Laser Printer Option + Transcript is a very useful collection
of tools to have around anyway, for converting Troff source to PS etc.

Be prepared, however, to wait a while for full screen dumps to print.
The PostScript code generated by "pprint" uses the native PS operator
"image" which converts grey level values in the range 0-255 into
dithered/scaled/translated bitmaps (0/1) **in the printer**.  This
compute intensive operation combined with the data transfer time
for a 1280x1024 image can result in print times of 20-50 minutes!
(on an Apple LaserWriter Plus).


+---------------+   David Laur
| "a bizarre    |   Princeton University
|  underwater   |   Interactive Computer Graphics Lab
|  scenerio..." |   Internet: dmlaur at magritte.princeton.edu
+---------------+   Bitnet: dmlaur at pucc