NAME¶
ppmtoicr - convert a portable pixmap into NCSA ICR format
SYNOPSIS¶
ppmtoicr [
-windowname name] [
-expand expand]
[
-display display] [
-rle] [
ppmfile]
DESCRIPTION¶
Reads a portable pixmap file as input. Produces an NCSA Telnet Interactive Color
Raster graphic file as output. If
ppmfile is not supplied,
ppmtoicr 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.
ppmtoicr 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.
OPTIONS¶
- -windownamename
- Output will be displayed in name (Default is to use
ppmfile or "untitled" if standard input is read.)
- -expandexpand
- Output will be expanded on display by factor expand
(For example, a value of 2 will cause four pixels to be displayed for
every input pixel.)
- -displaydisplay
- Output will be displayed on screen numbered
display
- -rle
- Use run-length encoded format for display. (This will
nearly always result in a quicker display, but may skew the
colormap.)
EXAMPLES¶
To display a
ppm file using the protocol:
ppmtoicr ppmfile
This will create a window named
ppmfile on the display with the correct
dimensions for
ppmfile, 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
cat 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
BUGS¶
The protocol uses frequent
fflush calls to speed up display. If the
output is saved to a file for later display via
cat, drawing will be
much slower. In either case, increasing the Blocksize limit on the display
will speed up transmission substantially.
SEE ALSO¶
ppm(5)
NCSA Telnet for the Macintosh, University of Illinois at Urbana-Champaign
(1989)
AUTHOR¶
Copyright (C) 1990 by Kanthan Pillay (svpillay@Princeton.EDU), Princeton
University Computing and Information Technology.