JulienB: creation

2008-06-06T20:24:11Z

creation

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==Introduction==
FBGrab is a framebuffer screenshot program, capturing the Linux framebuffer and converting it to a png-picture.

==Installation==
[host] $ make menuconfig
* then choose '''fbgrab''' in:
[[Image:Menuconfig_package.png]]<br><br>
[[Image:Menuconfig_package_graphics.png]]

==Usage==
* Just do:
# fbgrab toto.png
* Here is the full man page:
NAME
fbgrab - takes screenshots using the framebuffer device

SYNOPSIS
fbgrab [options] filename

DESCRIPTION
fbgrab reads the framebuffer device (/dev/fb*) or a dump thereof and saves a PNG image file. You can use it for making screen‐
shots of of virtually any application, from traditional test applications to your X-windows desktop, as well as framebuffer
applications.

OPTIONS
-? print usage information.

-b bitdepth
the number of bits per pixel used, optional when reading from device.

-c console
specifies which console (or virtual terminal - like other people call this feature) to grab. Sometimes this changing is
faster then the framebuffer is refreshed (especially when grabbing framebuffer apps). If so, you should use -C console
... This waits some time before grabbing. You can’t use -s in this case.

-d device
specifies which framebuffer device you want to read. If you do not use this option, it takes the value from the FRAME‐
BUFFER environment variable. If no FRAMEBUFFER environment variable is given or if its value is NULL, then DEFAULT_FB is
taken. (see source code), which usually is /dev/fb0.

-f filename
Read from from file instead of device, requires that -w (width), -h (height) and -b (bitdepth) are specified.

-h height
the height of the frambeuffer in pixels, optional when reading from device.

-i turns off interlacing. If you do not want ADAM7 interlacing, you should use the -i option.

-s seconds
specifies how many seconds to wait before grabbing. fbgrab does not lock console switching, so you can switch it while
waiting, if you cannot use -c requires normally that fbgrab is run as root.

-w width
the width of the frambeuffer in pixels, optional when reading from device.

TODO
* Low-end bit depths, eg 1, 2, 4 & 8 bits.

* Grab just part of framebuffer/file.

* Companion program fbput that would display a picture in the frambuffer.

* Better utilization of the PNG-lib, all formats are first converted to 32 bitdepth and then stored as PNG - hardly the right
approach.

BUGS
Some framebuffer seams to store the data for one fixed resolution even if the resolution is set to something lower. In these
cases the fixed size has to be specified and the picture has to be cut in a separate program afterwards.

EXAMPLES
fbgrab fb.png

will take a framebuffer snapshot, or if you don’t have fbgrab at your machine, you can do

cat /dev/fb0 > framebuffer.dump

and then

fbgrab -w 1024 -h 768 -b 16 -f framebuffer.dump fb.png

to convert it to a picture.

AUTHOR
Written by Gunnar Monell <gmo@linux.nu>. Basically a rewrite of fbshot by Stephan Beyer <fbshot@s-beyer.de>

COPYRIGHT (C)
(C) 2002 Gunnar Monell <gmo@linux.nu>

(C) 2000 Stephan Beyer <fbshot@s-beyer.de>

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

==Links==
* [http://hem.bredband.net/gmogmo/fbgrab/ FBGrab HomePage]

[[Category:Framebuffer]]

FBGrab - Revision history

JulienB: creation