XV
(http://olympic.atmos.colostate.edu/xvman.html)
6. xv:
The following is a brief excerpt of the man page for xv.
See the actual man page for more details or just type
xv and then hit your right mouse button in the xv window to
get started...it is very easy to use. xv is useful to capture
GIF images off of RDSS/editor for color plotting.
NAME
xv - interactive image display for the X Window System
SYNTAX
xv [options] [filename [filename...]]
DESCRIPTION
xv is an X11 program that displays images in the GIF, JPEG,
TIFF, PBM, PGM, PPM, X11 bitmap, Utah Raster Toolkit RLE,
PDS/VICAR, Sun Rasterfile, and PM formats on 1-, 2-, 4-, 6-,
8-, 16-, 24-, and 32-bit X displays. xv will also read
compress-ed versions of these files.
SECTION 1: OVERVIEW
xv version 2.10 lets you do a large number of things (many
of them actually useful), including, but not limited to, the
following:
o display an image in a window on the screen
o display an image on the root window, in a variety of
styles
o grab any rectangular portion of the screen and turn it
into an image
o arbitrarily stretch or compress the image
o rotate the image in 90-degree steps
o flip the image around the horizontal or vertical axes
o crop a rectangular portion of the image
o magnify any portion of the image by any amount, up to
the size of the screen
o determine pixel values and x,y coordinates in the image
o adjust image brightness and contrast with a gamma
correction function
o apply different gamma functions to the Red, Green, and
Blue color components, to correct for non-linear color
response
o adjust global image saturation
o perform global hue remapping
o perform histogram equalization
o edit an image's colormap
o reduce the number of colors in an image
o dither in color and b&w
o smooth an image
o crop off solid borders automatically
o convert image formats
o generate Encapsulated PostScript