Switch monochrome systray icon color depending on systray brightness

[svkurowski]

I am working on issue #2215 in this branch.

As of version 10.10 Yosemite, Mac OS X offers the user the option to use a dark version of the dock and menu bar. The systray icon was black even on the dark menu bar , thus rendering it nearly impossible to spot.

This patch checks the NSUserDefaults to check whether the user has chosen the black dock and if so, will use the white monochrome versions for the systray icons.
White icon on dark menu bar:

Right now, the systray icon will not change "live", that is it will stay in the old color when the user changes the dock/menu bar brightness during execution of the app until either the icon image changes (because of state change) or the app is restarted.

The patch needs to be tested on Unix and Windows systems, unfortunately I don't have a development machine setup for those operating systems at the moment. The systray icon behaviour should be unchanged for those operating systems and for earlier versions of OS X.

[dragotin]

I like the patch, thanks for caring!
Questions:

• Do we have the black icons already?
• The implementations of hasDarkSystray_private() for Linux and Windows are never really used, right?

Overall 👍

[svkurowski]

Previous Behaviour:

• Mac Systems always used the black icons, because the menu bar was always in a light color (usually a light gray). So yes, the black icons were already included
• Windows and Unix Systems always used the white icons

New Behaviour:

• Mac Systems will use black icons, unless the user is on OS X 10.10 Yosemite and has selected the dark dock / menu bar in general settings (System Preferences.app, not in owncloud.app), in which case the white icons will be used
  
• Windows and Unix Systems will use the white icons

Regarding the use of hasDarkSystray_private():
Obviously those functions will also get called on windows and unix respectively, however because they always return true; any decent compiler will optimize them (and probably also the calling of the ternary conditional operator) away when compiling for production. However, this implementation allows for easy switching of monochrome colors on other systems too. Imagine Gnome implementing an option to have a white menu bar - it will be very easy to adjust to that (as long as we're able to differ a systems running Gnome from one running, say, KDE).

[karlitschek]

@dragotin Got the contributor agreement

[wagnerand]

Would you mind backporting this to the 1.7 branch, please?

[svkurowski]

Sorry for the delay. I cherry-picked the commit into the 1.7 branch in 01a7212

[danimo]

Why? there will be no 1.7 release, and 1.8 is pending.

[svkurowski]

I was not aware of that. It doesn't hurt though I guess. If you want me to, however, I can revert it.