Dragging the slider produces a lot of events, and processing these makes
the UI lag behind because of the many helper calls. Let's update the
brightness level only after a small timeout.

Thanks to Simon for pointing out that a custom menu item would
accomplish what we need and for pointing out the ubuntu app
indicator code that this patch was based on. Additional thanks
need to go to Cody Russell for creating a custom menu slider
widget I could copy.

If this branch gets merged in the brightness plugin will no longer
be required so let's drop it now. The functionality is present in
the battery plugin.

This way it won't show as two different menu items.

This will consolidate the plugins which can then be renamed.
There's an issue where the mouse grab on the brightness slider
doesn't work, hopefully we can do that without making a custom
popup window. Scrolling on the plugin icon or over the brightness
slider does work.

Eric Koegel authored 10 years ago and Harald Judt committed 10 years ago

Signed-off-by: Harald Judt <h.judt@gmx.at>

While more complicated, this fixes the sliders having different length
and positions.

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Transifex (https://www.transifex.com/projects/p/xfce/).

206 translated messages.

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Transifex (https://www.transifex.com/projects/p/xfce/).

206 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).

206 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).

206 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).

205 translated messages, 1 untranslated message.

Transifex (https://www.transifex.com/projects/p/xfce/).

206 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).

206 translated messages.

Transifex (https://www.transifex.com/projects/p/xfce/).

On startup, save the kernel brightness switch setting and restore it
on exit. If xfce4-power-manager has crashed, restore it on the next
run.

On most machines, especially those using the video module backlight, the kernel
will already have hooked up the brightness keys. If the user wants to use
xfce4-power-manager to control the keys, then we need to disable this module
setting to avoid conflicts like brightness lowered or raised twice on key
presses.

Of course, it would be nice if the power manager restored the original setting
when it gives control back to the kernel or on exit. To be able to do this,
it needs to remember the value.

It is best to do this in a xfconf setting so it survives crashes. This way,
power manager has a chance of restoring the original setting even after a
crash, so that the user will not have to fix it manually.

There are three possible settings, read from
/sys/module/video/parameters/brightness_switch_enabled:

 1 = kernel brightness switch setting is enabled (value 'Y')
 0 = kernel brightness switch setting is disabled (value 'N')
-1 = kernel brightness switch unavailable or could not be read

Similar to xfpm-power we set this up in xfpm-backlight.