Enable battery widget in Deere skin

[rrrapha]

Having the widget enabled in skins make testing the feature easier..
The icons are a modified version of those posted here by user "jus":
https://bugs.launchpad.net/mixxx/+bug/1662336

Of course, someone more competent should adjust the style of the widget, this is just a placeholder.

[rrrapha]

I don't really understand this change, it seems to be needed to make the scaling work..

[daschuer]

The original version draws a into a rect taken from the prixamp placed at 0,0 of the widget.
The new version takes the whole widget rect as desired.

[ronso0]

Of course, someone more competent should adjust the style of the widget, this is just a placeholder.

for now you can use the icons in
https://github.com/mixxxdj/mixxx/tree/master/res/skins/Tango/graphics/batt
you can also rotate them ccw if that fits better

[rrrapha]

@ronso0 Thanks, I think it doesn't matter much for now..
(unless the icons from Tango are considered 'final' for Deere)

[daschuer]

Thank you. Unfortunately this PR mixes a finished bugfix with an unfinished skin change.
Can you do a separate PR only containing the scaling fix?

[rrrapha]

Can you do a separate PR only containing the scaling fix?

Sure, #2163

[daschuer]

What is the status of this PR?

[rrrapha]

I wouldn't mind if it gets merged as is, the icons can still be changed later if desired..

[ronso0]

on my ubuntu studio 18.04 machine the battery status in xfce4 works, but not the widgetin Mixxx:
"Battery status unknown"

upower / libupower are up to date AFAICT 0.99.7-2ubuntu0.18.04.1

same result with locally build master and mixxx-2.3.0-alpha-pre-master-git6883-release-bionic-amd64.deb from http://downloads.mixxx.org/builds/master/release/ , both built with battery=1

[rrrapha]

@ronso0 Do you have the dbus daemon running?
You can use the command line binary to check if upower works:
$ upower --dump

[ronso0]

dbus is running and $ upower --dump gives me adequate output, also the OS indicator is always running reliably

[rrrapha]

Strange, it works for me on OpenBSD (with upower 0.99.9).

[daschuer]

I can confirm the battery status unknown issue with Ubuntu Xenial.
$ upower --dump works.

[rrrapha]

My guess is that no devices are found with upower <= 0.99.7.
The following code in src/util/battery/batterylinux.cpp looks suspicious:

#if UP_CHECK_VERSION(0, 99, 8)
    GPtrArray* devices = up_client_get_devices2(client);
    VERIFY_OR_DEBUG_ASSERT(devices) {
      return;
    }
#else
    // This deprecated function doesn't set the free function for
    // the array elements so we need to do it!
    // https://bugs.freedesktop.org/show_bug.cgi?id=106740
    // https://gitlab.freedesktop.org/upower/upower/issues/14
    GPtrArray* devices = up_client_get_devices(client);
    VERIFY_OR_DEBUG_ASSERT(devices) {
      return;
    }
    devices = g_ptr_array_new_with_free_func((GDestroyNotify) g_object_unref);
#endif

    for (guint i = 0; i < devices->len; ++i) {
      ...

[ronso0]

As first implementation this is ready to merge IMO.

The lower the battery charge drops the more warning the icons should be colored:
yellow > orange > pink/red
Yes, this will happen in another PR.

[daschuer]

Cool. Thank you. LGTM.

[Be-ing]

This is a nice change. Could you add the battery widget to the other skins too?