TabContainer should use Tabs instead of reimplementing them

[akien-mga]

As discussed today on IRC [0], TabContainer scene/gui/tab_container.cpp should be modified to rely on Tabs scene/gui/tabs.cpp instead of reimplementing tabs itself.

The Tabs class has grown to be feature-rich (though it could still use some cleanup even after #4506), so it should stay as the sole implementation.

[0] http://godot.eska.me/irc-logs/devel/2016-05-01.log

[StraToN]

Tabs is the class describing only the tab buttons on top of the TabContainer. There is no Container in the Tabs class, simply each tab sends a signal when an action happens on it: tab_changed(int tab_clicked), tab_close(int tab_clicked) and right_button_pressed(int tab_clicked).

Thus, since Tabs buttons should only be used as such (ie. as "simple Button"s), Tabs class may itself have the container. I can take that one.

[akien-mga]

Well I think the idea would be to keep TabContainer, but replace its own tab "buttons" by an instance of Tabs.

[StraToN]

Alright. I'm in ;)

[Anutrix]

Any updates?

[YuriSizov]

From the recent discussions it's not clear if we want to keep both, delete one, or make them work together. There is a proposal for removal: godotengine/godot-proposals#2129 There are also several proposals for features in TabContainer that could be solved by a more unified solution.

At any rate, there needs to be a proper proposal now for any change like that. So, closing.

[akien-mga]

In the end, this was implemented for 4.0 by #58687.

For the record, this old issue was superseded by the proposal godotengine/godot-proposals#2514 which the above PR implemented.