Section: User Commands (1)
Updated: 30 July 1990
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.
- Output will be displayed in name (Default is to use ppmfile or "untitled" if standard input is read.):
- 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.):
- Output will be displayed on screen numbered display:
- Use run-length encoded format for display. (This will nearly always result in a quicker display, but may skew the colormap.):
To display a ppm file using the protocol:
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
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.
Copyright (C) 1990 by Kanthan Pillay ([email protected]), Princeton University Computing and Information Technology.