Have "changing" and "changed" signals in Range controls

[Zylann]

Currently, there is only one value_changed signal in Sliders, which is called continuously as the user drags the thumb. This is fine to be able to see the change as we change the value, however when the change is heavy, having it to update continuously results in lag.

The idea is to have two signals then:
changing which is called when the value changes,
changed when the user finished to drag the slider, OR, has clicked once without dragging (having also changed the value).
Names aren't specially important, just pick some that make sense.

Note: I think it would also make UndoRedo easier to implement because we would know when editing finishes.

[timoschwarzer]

I would keep value_changed and add two new signals like drag_started and drag_stopped.
1st this would be backwards compatible and actually the value is being changed while you are dragging.

[EveAwesome]

personally, I'd prefer released() as suggested in closed issue 7056

[Favorlock]

Is this being addressed at all?

[Calinou]

@Favorlock It seems nobody is currently working on this feature. Pull requests are welcome 🙂

I'd go for adding new drag_started and drag_stopped signals so this can be backwards-compatible. This way, we could cherry-pick the change into 3.2.x.

[Zylann]

I slightly updated the first post as I had this use case again but had to clarify something. It's not just about dragging

[lupoDharkael]

For mouse detection I'd add slider_pressed and slider released.

Maybe we could approach this the Qt way and implement a tracking property, if tracking is false value_changed is only emitted when we change the value with keyboard or when we finish moving the slider with the mouse. With tracking set to true the signal would behave the same as the actual implementation.

They also define a signal called sliderMoved(value) which emits the value inconditionally and it serves to preview the changes even with tracking set to false as it would only notify a value at the end of the user interaction.

[Giwayume]

Can I request the slider documentation be updated with the list of signals as well? I have great difficulty finding which signals are available for controls.

https://docs.godotengine.org/en/3.2/classes/class_slider.html#class-slider

[akien-mga]

@Giwayume All signals are in the documentation. Slider doesn't have specific signals, all its signals are inherited from Range, Control, etc.

Click the classes in the "Inherits" line for the documentation of each parent class.

[vortex-captain]

I found a GDScript solution, which works fine with mouse dragging (not tested on a touchscreen though)

extends VSlider

signal drag_started
signal drag_stopped

func _input(event):
	if event is InputEventMouseButton:
		if event.is_pressed():
			emit_signal("drag_started")
		else:
			emit_signal("drag_stopped")	

reference: https://stackoverflow.com/a/51687109

[Zylann]

This is going to emit even when the value didn't change. Also I'm not sure it will work properly with spinboxes.