At first, "./autogen.sh -> ./configure -> make -> make install" hasn't worked fine yet so you need to install manually :( I'll fix it.
Anyway, it requires lxpanel and libXrandr development libraries. If you are using Fedora you need to install libXrandr-devel and lxpanel-devel packages. I tested it on Fedora 16.
$ make DESTDIR=/path/to/temporary install
Check where lxpanel applets and icons are installed. For example, Fedora(x86_64) installs plugins are in /usr/lib64/lxpanel/plugins/ and icons are in /usr/share/lxpanel/images/
Then copy files
# cp /path/to/temporary/usr/usr/lib/lxpanel/plugins/backlight.so /usr/lib64/lxpanel/plugins/.
# cp /path/to/source code directroy/data/bklight.png /usr/share/lxpanel/images/.
3. Add applet
Add "Backlight Control" to your lxde panel
It source code is in my github repogitory.
btw, quick look xbacklight. It is a simple tool but is useful. There is some options to change brightness. The "set" option to set brightness given percentage. The "inc" and "dec" options to increment/decrement given percentage from current setting.
[masami@rune]~% xbacklight -h usage: xbacklight [options] where options are: -display <display> or -d <display> -help -set <percentage> or = <percentage> -inc <percentage> or + <percentage> -dec <percentage> or - <percentage> -get -time <fade time in milliseconds> -steps <number of steps in fade>
Ok, let's see how it works. It's really easy, isn't it?
[masami@rune]~% xbacklight 100.000000 [masami@rune]~% xbacklight -set 50 [masami@rune]~% xbacklight -get 50.000000 [masami@rune]~% xbacklight +20 [masami@rune]~% xbacklight 62.500000 [masami@rune]~% xbacklight -dec 50 [masami@rune]~% xbacklight 12.500000 [masami@rune]~%