XGRABSC(1X)XGRABSC(1X)NAMExgrabsc - grab rectangular screen images and store in files
SYNOPSISxgrabsc [-d display] [-id windowId] [-colorwin windowId] [-o output‐
File] [-s seconds] [-post seconds] [-b percent] [-and andBits]
[-or orBits] [-page widthxheight-hmarg-vmarg] [-bell-grab
-verbose -borders -frame -key -stretch -root -click-coords
widthxheight+x+y -offset widthxheight+x+y
-reverse -bw -mdither -dither -halftone
-ps -cps -simple -xwd -ppm -xwdxy -bm -bm2 -bm3 -puzzle
-bin -comp -eps -l -limit -preview -prev -previewonly -colproc]
DESCRIPTIONxgrabsc lets you grab arbitrary rectangular images from an X server and
writes them to standard output in a variety of formats.
Command line options also allow reduction of colormaps, halftoning and
dithering of color images, and direct mapping of color images to mono‐
chrome.
Options must be seperated with spaces or tabs. They may be preceded
with a dash, but this optional and provided for Un*x addicts. Many may
also be prefixed with 'no', or an additional dash, to turn them off.
The default output format is gray-scale non-encapsulated Postscript,
with image compression (if image compression significantly reduces the
amount of output).
If you desire an output format not produced by xgrabsc, try using the
PBM package by Jef Poskanzer to convert xgrabsc to that format. PBM
can read xgrabsc's PPM and XWD output formats and convert them to a lot
of different formats.
GENERAL OPTIONS-d displayName or -display displayName
Use an alternate display. If no display is specified on the
command line, xgrabsc looks for the environment variable DIS‐
PLAY for the name of the display and screen to grab from. Note
that you must have permission to access the display on another
computer.
-bell The display's bell is normally rung while the screen is being
accessed. This turns the bell on or off (-nobell will turn it
off).
-grab Enable server grabs. Normally xgrabsc will "grab" the server
so that the screen is frozen while a rectangle is selected and
the image is extracted. If the screen is not frozen, rubber-
banding may cause video droppings on portions of the screen
that are changing. Use -nograb to turn off server grabs.
Server grabs are automatically disabled if verbose output is
requested to avoid freezing up the system.
-o output-file or -output output-file
Write output to output-file instead of standard output. The
output-file name, minus directory and extension, is used as the
internal name for the image in formats supporting image names.
Postscript, xwd, pixmap and bitmap formats all support image
names.
-s seconds or -sleep seconds
Sleep for seconds seconds before commencing operation. This
should be used if you need some time to get the target image
ready.
-post seconds
Sleep for seconds seconds after window/rectangle selection.
This is commonly used to pop up menus after a window has been
selected but before xgrabsc takes its snapshot.
-verbose
Display processing information on standard error output
(stderr).
SELECTION OPTIONS-id window ID
Dump the window with the given ID. ID numbers can be in deci‐
mal, or hexidecimal (prefixed with "0x"). The name of a window
can be given instead of an ID number, and xgrabsc will look for
the first window with that name.
-key Select the window under the mouse when the Control key is
pressed. This option is normally used in getting images of
menus. Pop up the menu, optionally move the pointer to the win‐
dow containing the menu, and strike the Control key to begin the
dump.
-root Dump the entire screen (root window).
-stretch
Use rubber-band rectangle to select region to grab. This is the
default.
-click Wait for a click on a window and dump the selected window.
-coords widthxheight+x+y
Selects the given area of the screen, without mouse or keyboard
interaction. Use this if you need to grab the same area of the
screen over and over again. Standard X coordinate notation can
be used, but a width and height must be given.
-coords widthxheight+x+y
Offsets the area to be grabbed by x@y and changes the area's
width and height to widthxheight. Using this you can grab a
sub-area of the source area, or even grab an area adjacent to
the source area.
IMAGE PROCESSING OPTIONS-nobdrs or -noborders
Remove window borders from window images. This option applies
only to selection by ID (-id) or xwd-style selection (-click).
Note that Motif-style window frames are not window borders. To
remove these you should use the -noframe option. The xgrab win‐
dow interface's Include Borders option removes both frames and
borders.
-bdrs or -borders
Include window-manager borders in window images. This option
applies only to selection by ID (-id) or xwd-style selection
(-click). Use -nobdrs or -noborders to turn it off.
-b percent or -brighten percent
brighten or darken the image by percent. Percentages are given
as integers. 100 is the base and a larger number will brighten
the image while a smaller number will darken the image.
-and andBits
Clear all colormap bits up to the given plane. This has the
effect of darkening the image somewhat and shrinking the appar‐
ent depth of the image (and, consequently, the size of the color
table). AndBits should be in the range [1-8] inclusive.
-or orBits
Set all colormap bits up to the given plane. This brightens the
image somewhat and also shrinks the apparent depth of the image.
When both -A and -O are specified, ANDing will occur before
ORing.
-reverse
Reverse the colors in the image. The bits of each color used in
the image are inverted.
-bw Convert the source color image to a monochrome bitmap. All col‐
ors falling below the average color intensity are mapped to
black. Others are mapped to white.
-halftone
Convert the source color image to a halftoned monchrome bitmap.
Resolution is maintained by increasing the size of the image by
a factor of four on both axes.
-mdither
Convert the source color image to a dithered monochrome bitmap.
This is like halftoning, but resolution is sacrificed to keep
the resulting image the same size as the original. The matrix
dithering algorithm used with this option is most suitable for
line-drawings and text. For more complex graphics the -dither
option is recommended.
-dither
Convert the source color image to a dithered monochrome bitmap
with the Floyd-Steinberg algorithm.
-nodither
Turns off any dithering. Use this if your XGRABSC environment
variable specifies dithering and you want to override it to pro‐
duce an undithered image.
-colorWin windowId
Specifies a window id (in hex) whose colormap should be used for
the grabbed image. Generally xgrabsc will find the correct col‐
ormap for your image. If you have lots of private colormaps
around you may need to use this option to ensure that xgrabsc
selects the proper one.
ID numbers can be in decimal, or hexidecimal (prefixed with
"0x"). The name of a window can be given instead of an ID num‐
ber, and xgrabsc will look for the first window with that name.
OUTPUT FORMAT OPTIONS-cps Write output in Postscript format using the colorimage operator
for color printers. Color to grayscale conversion is bundled
into the output so you can actually use either color or cheaper
grayscale printers. For monochrome displays, the -ps option
will give more compact output.
-ps Write output in Postscript format for greyscale printers. The
number of bits per Postscript sample is determined by the depth
of the image.
-ppm Write output in Portable Bitmap format. Unix image viewers such
as xv and ImageMagick can accept this format, and the Portable
Bitmap package can convert this to many other image formats.
-xwd Write output in xwd format. Use this if you want to convert to
another output format with Pbm+.
Write output in xwd -xy format. This is like xwd, but allows black and
white images to be written with eight pixels per byte instead of
the default one pixel per byte. While xwud and xpr will handle
this format, some programs will not.
-bm Write the output in X Bitmap format if the image is black and
white, or X Pixmap format if the image is gray or color.
-bm2 Write the output in X Bitmap format if the image is black and
white, or X Pixmap format 2 if the image is gray or color. -bm3
Write the output in X Bitmap format if the image is black and
white, or X Pixmap format 3 if the image is gray or color.
-puzzle
Write output in a format suitable for loading into the puzzle
program (see example below).
POSTSCRIPT OPTIONS-compress
Enable or suppress Postscript image run-length encoding. Post‐
script output is normally compressed to minimize the size of
output. If your printer can't handle compressed output, you
should use -nocompress to turn off compression.
-eps Create Encapsulated Postscript output, rather than normal stand-
alone Postscript. This adds EPSF header comments and removes
all scaling and translation of the image.
-l or -landscape
Use landscape layout (with page width and height exchanged) for
Postscript output. This option is ignored if Encapsulated Post‐
script output is requested. Width and height may be specified
with the -page option.
-bin Write Postscript output in binary rather than using hexidecimal
encoding. This causes the image portion of the output to use
half as much space, decreasing transmission time to the printer.
Note that not all print spoolers can handle 8 bit binary data,
so this may not work on your system!
-limit For Postscript output, check printer memory availability before
attempting to print an image (the code to perform the checks is
integrated into the output of xgrabsc). This is turned off if
Encapsulated Postscript output is requested, and may be disabled
completely when building the xgrabsc program. On the command
line it may be turned off with -nolimit.
-preview or -prev
Selects Encapsulated Postscript output with an EPSI preview
image in its header. The preview image, if necessary, is
dithered to black and white either with a default dithering
algorithm or one you specify on the command line (e.g.,
-mdither). Programs such as Frame use preview images to display
the postscript image during editing sessions. If you don't have
a preview image, Frame will display a blank rectangle. The
image will print OK but you won't see it while editing.
-previewonly
Like -preview but writes only the preview portion, not the post‐
script image. This may be used to add the preview to an exist‐
ing EPS file after having displayed it using a PostScript inter‐
preter.
-page widthxheight-marginWidth-marginHeight
Sets the size of the paper and the borders you desire around the
edge of the paper. Xgrabsc will reduce the image if necessary
to keep it within the borders you specify. The default page
size and margins are set when xgrabsc is built. Measurements
are in inches (e.g., 8.5x11.0-0.5-0.5)
PROCESSING ORDER
It is helpful to know the order of processing when multiple processing
options are given on the command line.
Processing is done in five phases: 1) set up, 2) obtain image, 3)
process colors, 4) poly->monochrome conversions, and 5) output conver‐
sion.
The set-up phase includes processing command-line options, sleeping,
connecting to X-Windows, freezing the screen, and grabbing the mouse if
necessary.
If the mouse is grabbed for rubber-banding, an upper-left-corner cursor
is displayed until the left mouse button is pressed. A lower-left-cor‐
ner cursor is then displayed while drawing rubber-rectangles until the
mouse button is released.
If the mouse is grabbed for xwd-style window selection, an xwd-style
cursor is displayed until the left mouse button is pressed.
The mouse is then released.
The bell is then run and the image is pulled from the screen.
Following the image-grab, the bell is run twice and the screen is
released.
If the image is not monochrome, the color manipulation functions are
then applied in this order: brighten, AND, and OR, reverse.
Only one polychrome to monochrome conversion is allowed. If none of
these is chosen, the color table of a polychrome image is compressed in
preparation for output conversion.
The output stream is then opened and the image is written in the
selected output format.
ENVIRONMENT
XGRABSC - specifies command line arguments to be processed before those
actually entered on the command line.
DISPLAY - specifies the name of the display that xgrabsc should grab
from.
EXAMPLES
The simplest form of use, giving Postscript output, is
xgrabsc >outfile.ps
To write output in Postscript format and send to the printer, use
xgrabsc | lpr
It is sometimes helpful to brighten an image somewhat before it is for‐
matted for Postscript output. E.g., to brighten by 30%
xgrabsc-b 130 | lpr
If your printer supports color, and your display is color, you can have
xgrabsc generate color output instead of gray scale:
xgrabsc-cps | lpr
The default Postscript output attempts to scale the image so that it
will all fit on one page, and is centered on the page. If you are
grabbing images to include in documents, such as with FrameMaker, you
should ask for Encapsulated Postscript output with the -eps switch.
For example:
xgrabsc-eps -o image1.eps
To select an entire window, write output in puzzle format and read into
the puzzle program, use the commands
xgrabsc-click -puzzle >outfile.pzl
puzzle -picture outfile.pzl
To have xgrabsc sleep for three seconds before rubber-banding, display
processing information, and have the result displayed with xwud,
xgrabsc-xwd -verbose -s 3 | xwud
To grab an image from another server and then reduce the colormap to
three bits by ANDing, use
xgrabsc-d other:0.0 -and 5 -bm >outfile.xpm
You will, of course, have to go to the other machine to select the
image with that machine's mouse.
If you know the name or ID number of the window you want to snapshot
you can direct xgrabsc to that window on the command line. Utilities
like xlswins or xwininfo can be used to find the names and ID numbers
of windows.
To grab an mpegplay image and display it in xwud, use
xgrabsc-xwd -id "MPEG Play" | xwud
You can also specify a sub-region to grab, as in
xgrabsc-xwd -id "MPEG Play" -offset 100x100+10+10 | xwud
Grabbing an area with the /fI-coords/fP option will use the root win‐
dow's colormap unless you specify an alternate window to use for color
processing. If your display allows more than one colormap to be
installed at once and you are displaying an mpeg video that uses a pri‐
vate colormap, your output using the /fI-coords/fP command would be
technicolor without a /fI-colorwin/fP option specifying the mpeg win‐
dow. E.g.,
xgrabsc-xwd -coords 300x300+10+10 -colorwin "MPEG Play" | xwud
LIMITATIONS
Colormaps larger than 256 entries are not currently supported. This
means that it won't work with your fancy 24-bit display.
The default screen visual is used as the visual for the image. Visuals
are associated with particular windows, and xgrabsc pretends ignorance
about any windows but the root.
This software has been tested with StaticGray and 8-plane PseudoColor
on DECStations (using both UWS 2.2 and X11 Release 4). It has also
been tested with 8-plane PseudoColor on Sun SparcStations and various
other platforms using X11 Release 4 and Release 5.
X11 Pixmap format is rather verbose. You may want to run large images
through the compress utility before storing them in a file. E.g.,
xgrabsc-bm | compress >outfile.xpm.Z
AUTHOR
Bruce Schuchardt
GemStone Systems, Inc.
bruce@slc.com
ACKNOWLEGEMENTS
Some of the source code for xgrabsc came from the xloadimage project by
Jim Frost (jimf@saber.com) and others. Jim's copyright has been
included both here and in the source code.
The idea for using run-length encoding for Postscript output came from
the xwd2ps project by Robert Tatar and Craig A. McGowan.
The ad2c.sed script that makes it possible to let you run xgrab without
installing XGrab.ad everywhere is part of the ad2c package developed by
George Ferguson.
CONTRIBUTORS
Yves Arrouye wrote the EPS Preview and page-configuration enhancements.
COPYRIGHT
Copyright (c) 1990-93 Bruce Schuchardt
Xgrabsc is copywritten material with a very loose copyright allowing
unlimited modification and distribution if the copyright notices are
left intact. Various portions are copywritten by various people, but
all use a modification of the MIT copyright notice. Please check the
cpyright.h for complete copyright information. The intent is to keep
the source free, not to stifle its distribution, so please write to me
if you have any questions.
THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSE‐
QUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PER‐
FORMANCE OF THIS SOFTWARE.
SEE ALSOX(1X), xhost(1), xwd(1X), xwud(1X), xwd2ps(1X), xloadimage(1X),
xpm(1X), xpr(1X), puzzle(1X), compress(1), uncompress(1), xv(1X)XGRABSC(1X)
