NAME
getx11 - get RLE images to an X11 display
SYNOPSIS
getx11 [ -= window_geometry ] [ -a ] [ -d display ] [ -D ] [ -f ] [ -g
display_gamma ] [ -{iI} image_gamma ] [ -j ] [ -m [ maxframes/sec ] ] [
-n levels ] [ -s ] [ -t title ] [ -v ] [ -{wW} ] [ -x visualtype ] [
infile ... ]
DESCRIPTION
This program displays an RLE(5) file on an
X11 display. It uses a dithering technique
to take a full-color or gray scale image into
the limited number of colors typically
available under X. Its default behavior is
to try to display the image in color with as
many brightness levels as possible (except on
a one bit deep display). Several getx11
processes running simultaneously with the
same color resolution will share color map
entries.
Getx11 uses the standard X window creation
procedure to create a window with a location
and size specified by the user, with the
restriction that the window must be at least
as large as the input image. If the window
is turned into an icon, a smaller version of
the image will be displayed in the icon.
If the input image has only a single channel,
and has a color map, then this color map will
be loaded directly (if possible) instead of
using the normal dithering process. Many
images will look better if pre-processed by
mcut(1) or rlequant(1), both of which produce
images reduced to a single channel with a
colormap. This is because the colors that
are used to display the image are chosen to
be a good set of colors for that particular
image, rather than a set of colors that are
mediocre for all images. The color map so
created will not be shared with other
windows. The picture comment colormap_length
specifies the exact number of useful entries
in the input color map. If this is
significantly less than 256, this can save
space in the shared X color map.
OPTIONS
9
-= window_geometry
Specify the geometry of the window in
which the image will be displayed. This
is useful mostly for giving the location
of the window, as the size of the window
will be at least as large as the size of
the image.
-a "As is", suppress dithering.
-d display
Give the name of the X display to
display the image on. Defaults to the
value of the environment variable
DISPLAY.
-D "Debug mode". The operations in the
input RLE(5) file will be printed as
they are read.
-f "No fork." Normally, getx11 will fork
itself after putting the image on the
screen, so that the parent process may
return the shell, leaving an "invisible"
child to keep the image refreshed. If
-f is specified, getx11 will not exit to
the shell until the image is removed.
-g display_gamma
Specify the gamma of the X display
monitor. The default value is 2.5,
suitable for most color TV monitors
(this is the gamma value assumed by the
NTSC video standard).
-i image_gamma
Specify the gamma (contrast) of the
image. A low contrast image, suited for
direct display without compensation on a
high contrast monitor (as most monitors
are) will have a gamma of less than one.
The default image gamma is 1.0. Image
gamma may also be specified by a picture
comment in the RLE (5) file of the form
image_gamma=gamma. The command line
argument will override the value in the
file if specified. The dithering
process assumes that the incoming image
has a gamma of 1.0 (i.e., a 200 in the
input represents an intensity twice that
of a 100.) If this is not the case, the
dithering.
-I image_gamma
An alternate method of specifying the
image gamma, the number following -I is
the gamma of the display for which the
image was originally computed (and is
therefore 1.0 divided by the actual
gamma of the image). Image display
gamma may also be specified by a picture
comment in the RLE (5) file of the form
display_gamma=gamma. The command line
argument will override the value in the
file if specified.
-j "Jump mode". When reading an image from
the standard input, each scan line is
normally displayed as soon as it is
read. This allows a user to monitor the
progress of an image generating program,
for example (common usage is "tail -f
image.rle | getx11"). Images read
directly from files are only updated
after every 10 lines are read to improve
the display speed. This behavior can be
forced for the standard input by
specifying jump mode.
-m [ maxframes/sec ]
"Movie mode." Optional argument is
maximum rate at which movies will play,
in frames per second.
-n levels
Specify the number of gray or color
levels to be used in the dithering
process. If not this many levels are
available, getx11 will try successively
fewer levels until it is able to
allocate enough color map entries.
-s "Stingy mode". Normally, getx11
allocates an X server pixmap for each
image to speed up the window refresh.
If many images are displayed, the server
may run out of memory to store these
pixmaps (or its virtual memory size may
get very large). Stingy mode suppresses
pixmap allocation (except in movie mode,
where the pixmaps are necessary for
-t title
The window name for an image window
normally comes from the input file name
or a image_title=title comment in the
RLE file. The window name can be forced
to a particular string with this option.
-v Verbose. (But less so than with -D.)
-w This flag forces getx11 to produce a
gray scale (black-and-white) dithered
image instead of a color image. Color
input will be transformed to black and
white via the NTSC Y transform. On a
low color resolution display (a display
with only 4 bits, for example), this
will produce a much smoother looking
image than color dithering. It may be
used in conjunction with -n to produce
an image with a specified number of gray
levels.
-W This flag forces getx11 to display the
image as a bitonal black and white
bitmap image. This is the only mode
available on monochrome (non gray scale)
displays (and is the default there).
Black pixels will be displayed using the
BlackPixel(3X) value and white with the
WhitePixel(3X) value (note that these
may not be black and white on certain
displays, or when they have been
modified by the user.)
-x visual_type
Specify X visual type to be used. The
value may be a string or a number. This
number is assumed to be an integer
between 0 and 5, denoting
staticgray(0),grayscale(1),
pseudocolor(2),staticcolor(3),
truecolor(4), or directcolor(5). The
string must match one of these visual
types (any capitalization is ignored).
infile ...
Name(s) of the RLE(5) file(s) to
display. If not specified, the image
will be read from the standard input.
9 - 4 Formatted: July 31, 1996
Mouse/key actions (normal mode)
Mouse 1 (left): Increase zoom factor by
1, center on this pixel.
Mouse 2 (middle): Recenter on this pixel.
Mouse 3 (right): Decrease zoom factor by
1, center on this pixel.
Shift mouse 1: Show value at this pixel.
In B&W, just shows
intensity.
Shift mouse 2: Toggle between zoomed and
unzoomed.
q,Q,^C: Quit.
1,2,3,4,5,6,7,8,9: Set zoom factor.
Arrow keys: Move image (when zoomed).
Shifted moves faster.
Mouse/key actions (movie mode)
Mouse 1: Run movie forward.
Shift Mouse 1: Run movie continuously in
current direction.
Mouse 2: Step movie one frame in
current direction.
Shift Mouse 2: Set movie speed by moving
mouse "up" and "down".
The speed chosen is
displayed in the upper
right corner of the
window.
Mouse 3: Run movie backward.
space: Flip one frame in current
direction.
b: "Bounce" image - run it
continuously forwards,
then backwards, then
9 - 5 Formatted: July 31, 1996
runs it backward. When
the movie reaches the
"end", it will
immediately restart from
the beginning. All
continuing movie action
can be halted by pressing
a key or mouse button.
SEE ALSO
urt(1), RLE(5).
AUTHOR
Spencer W. Thomas, University of Utah (X10
version)
Andrew F. Vesper, Digital Equipment Corp.
(X11 modifications)
Martin R. Friedmann, University of Michigan
(better X11, flipbook, magnification, info)
BUGS
Display to a 24-bit visual is somewhat
optimized, but could be faster.
Doesn't pay any attention to the X resource
database (i.e., cannot be customized via the
.Xdefaults file). The options, while
standard for the raster toolkit, are non-
standard for X.
9
- 6 Formatted: July 31, 1996