Godot: Labelled Sliders

[KoBeWi]

Godot version:
3.1.1

Issue description:
Right now Sliders don't support displaying their value and you need to implement it yourself (unless I'm missing something). Would be nice if they had an option to display a label with current value with some customization, namely whether it should be above or below and whether it should always show, only when dragging the slider or not at all.

A small mockup:

[girng]

have a feeling this could be done with a label as a child, and its position gets updated based on the value of the slider and width. i don't know if it needs to be done in c++ (added to core, or could be done in gds)

[Zireael07]

It can be done with a label, but it's such an ubiquitous feature that it's kinda weird not to have it out of the box.

[Zylann]

Looking at your mockup, is that label to be shown only when hovering and sliding?
If you really want to show that value at all times (and can't use EditorSpinSlider?), there would be more possibilities, because having it shown on top takes vertical space, and would be better placed on the left or the right, and could also be potentially editable.

[volzhs]

it might need many properties if engine has this feature.
font, h/valign, offset, show all time or only when dragging, how many number shown after dot for floating number, how to show lager number like 100K, using comma for every 1000 or etc...

[Calinou]

Feature and improvement proposals for the Godot Engine are now being discussed and reviewed in a dedicated Godot Improvement Proposals (GIP) (godotengine/godot-proposals) issue tracker. The GIP tracker has a detailed issue template designed so that proposals include all the relevant information to start a productive discussion and help the community assess the validity of the proposal for the engine.

The main (godotengine/godot) tracker is now solely dedicated to bug reports and Pull Requests, enabling contributors to have a better focus on bug fixing work. Therefore, we are now closing all older feature proposals on the main issue tracker.

If you are interested in this feature proposal, please open a new proposal on the GIP tracker following the given issue template (after checking that it doesn't exist already). Be sure to reference this closed issue if it includes any relevant discussion (which you are also encouraged to summarize in the new proposal). Thanks in advance!