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getx11 - get RLE images to an X11 display
- 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 ... ]
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.
- -= 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 input values must be adjusted before 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 reasonable performance).
- -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. In movie mode, you get one window,
and zooming is disabled. In normal mode, you get one window per image.
- 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 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 forwards, ...
- c,C:
- Run
move continuously. "c" runs it forward, "C" 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.
urt(1)
, RLE(5)
.
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)
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.
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