Section: User Commands (1)
Updated: 30 July 1990Index
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ppmtoicr - convert a portable pixmap into NCSA ICR format
Reads a portable pixmap file as input.
Produces an NCSA Telnet Interactive Color Raster graphic file as output.
is not supplied,
will read from standard input.
Interactive Color Raster (ICR) is a protocol for displaying raster
graphics on workstation screens. The protocol is implemented in NCSA
Telnet for the Macintosh version 2.3.
The ICR protocol shares
characteristics of the Tektronix graphics terminal emulation protocol.
For example, escape sequences are used to control the display.
will output the appropriate sequences to create a window of the
dimensions of the input pixmap,
create a colormap of up to 256
colors on the display, then load the picture data into the window.
Note that there is no icrtoppm tool - this transformation is one way.
Output will be displayed in
(Default is to use
or "untitled" if standard input is read.)
Output will be expanded on display by factor
(For example, a value of 2 will cause four pixels to be displayed for
every input pixel.)
Output will be displayed on screen numbered
Use run-length encoded format for display. (This will nearly always
result in a quicker display, but may skew the colormap.)
To display a
file using the protocol:
This will create a window named
on the display with the correct dimensions for
create and download a colormap of up
to 256 colors, and download the picture into the window. The same effect
may be achieved by the following sequence:
ppmtoicr ppmfile > filename
To display a GIF
file using the protocol in a window titled after the input file, zoom
the displayed image by a factor of 2, and
run-length encode the data:
giftopnm giffile | ppmtoicr -w giffile -r -e 2
The protocol uses frequent
calls to speed up display. If the
output is saved to a file for later display via
drawing will be
much slower. In either case, increasing the Blocksize limit on the
display will speed up transmission substantially.
NCSA Telnet for the Macintosh,
University of Illinois at Urbana-Champaign (1989)
Copyright (C) 1990 by Kanthan Pillay (svpillay@Princeton.EDU
Princeton University Computing and Information Technology.
- SEE ALSO