allow to hide the menu bar with [Controls],show_menubar

[ronso0]

supersede #927
https://bugs.launchpad.net/mixxx/+bug/1703777

Allows to hide the main menubar with [Controls],show_menubar.
I added a toolbar button to all skins except Shade. State is not persistent across restarts.

All keyboard shortcuts work regardless of the show/hide state.
Menus can be opened as before (like Alt + F for File menu).

ToDo

• ifdef APPLE: what happens to macOS global menu when hiding?
• hide the skin pushbutton via stylesheet if hiding isn't allowed in OS

Nice to have

• toggle menubar by pressing Alt
• bind to fullscreen?

[ronso0]

Does it make sense to read this after initialization, or keep it here in case fonts or decoration or whatever is changed by OS measures while Mixxx runs?

[poelzi]

I would incoperate this changes into #3189 if this approach gets greenlight, since I need this here next

[ronso0]

I would incoperate this changes into #3189 if this approach gets greenlight, since I need this here next

We need testing on all supported OS first, especially macOS with the global menu.

[ronso0]

I'll address the comments.

On the scenario:
Do we want to make the menubar always optional or automatically hide it (and show the button) when in fullscreen mode?

[Holzhaus]

I would say always optional (maybe add a skin flag, so that old skins that don't have the button keep working).

[ronso0]

Thinking about it, always optional is better as the user has to toggle the button to hide the menu and therefore implicitely knows how to recall it.

[ronso0]

rebased with comments addressed, m_bShowMenuBar is now a parented pointer.

The button is alway in the same place, also close to where the menu items are be shown.
When switching to Shade the menubar is enforced.

[poelzi]

@ronso0 I'm for #3189 instead of adding a button to show/hide the menubar. There is only one bug left that toggeling fullsceen recreates the menubar and therefor destroys the old association.

[daschuer]

We now have two similar menu buttons in the skins one for the application menu and one for the skin menu.

That is OK looking at the legacy, but feels unintuitive. Do we have an idea to improve it?

We may fix the shrink issue that makes the "skin preview" during setting the skin option void in turn.

I have in mind to integrate the skin menu as pop up widget into the view menu of the menu bar.
This way we have two clicks more to reach it on the down side, but screen reader support and a "real" preview on the up side.

What do you think? What are alternatives?

[daschuer]

On Ubuntu Bionic + Gnome, the Menu button stops working in full-screen mode and does not work again after leaving it.

Some issues are logged:

Warning [Controller]: USB permissions problem (or device error.) Your account needs write access to USB HID controllers.
Critical [Main]: DEBUG ASSERT: "!pCreatorCO" in function static QSharedPointer<ControlDoublePrivate> ControlDoublePrivate::getControl(const ConfigKey&, ControlFlags, ControlObject*, bool, bool, bool, double) at /home/daniel/workspace/advanced_autodj_2/src/control/control.cpp:118
Warning [Main]: ControlObject "[Controls]" "show_menubar" already created
Critical [Main]: DEBUG ASSERT: "!pCreatorCO" in function static QSharedPointer<ControlDoublePrivate> ControlDoublePrivate::getControl(const ConfigKey&, ControlFlags, ControlObject*, bool, bool, bool, double) at /home/daniel/workspace/advanced_autodj_2/src/control/control.cpp:118
Warning [Main]: ControlObject "[Controls]" "show_menubar" already created
Warning [LibraryScanner 1]: QSqlDatabasePrivate::removeDatabase: connection 'MIXXX-2' is still in use, all queries will cease to work.

[daschuer]

All Gnome based desktops suffer the issue of the broken button after full screen.
Unity works as expected. The Menu button is always out of work.
We may consider to make it work in full screen and hid it in windowed mode, where the menu has been moved to the global menu like in Mac OS.

[ronso0]

We may consider to make it work in full screen and hid it in windowed mode, where the menu has been moved to the global menu like in Mac OS.

Okay, thanks for testing.
Do the shortcuts work there and can you access the menus (for example Ctr+F) when the menu is hidden?
That what be good to know for whether I continue following this route or not.

I'll try to hide it in fullscreen only, regardless of the skin. Maybe I also get an eventFilter working that catches single-pressing Alt to show it again.

[daschuer]

In Unity, I have the issue to have no Menu bar when starting if full screen the first time.
In windowed mode ALT+O and Crtl+P works.
In Full screen mode ALT+O does not work but Crtl+P still works.

[daschuer]

In Full screen mode ALT+O does not work but Crtl+P still works.
This is the case if there is no menu bar visible when starting if fullscreen mode and when the menu is visible.

[daschuer]

With Gnome, unlike Unity, I see a menu bar starting in full screen mode.
Unfortunately ALT+O is still broken, Ctrl+P works.

[ronso0]

Closing this. Happy to have it in my personal branch until #3189 is merged :)