Knob: hide cursor on wheel event for .8s

[ronso0]

While working on #11041 I got bothered by the mouse pointer covering the effect parameter value when using the mouse wheel to turn the knob.

This hides the pointer like for mouse move (drag) events. Atm it's useful only for effect parameter knobs, but for consistency it's applied to all knobs.
Timeout is .8 seconds, the same time the parameter value is shown

[daschuer]

Good idea.

This kind of confirms my concerns of changing the mouspointer to a hand.

[daschuer]

Is only the pointer hidden or is the mouse kind of catched like when turning the knob klick+move
For my understanding we want the later?

[ronso0]

This kind of confirms my concerns of changing the mouspointer to a hand.

Your comment confirms my impression you've been mixing things up ; )
This is about the knob, the hand cursor is for the parameter label only.

Is only the pointer hidden or is the mouse kind of catched like when turning the knob klick+move
For my understanding we want the later?

Why would we want to lock the cursor position when scrolling? If you move the cursor while scrolling, that's okay, as soon as the cursor leaves the widget, the regular cursor is restored so it can always be located (unlike hiding it during drag events).
(this reminds me to unset the cursor in LeaveEvent so it can't be hidden by hovering the knob during the timeout (when not scrolling))

[daschuer]

Your comment confirms my impression you've been mixing things up ; )

Yes, you are right unfortunately.
I think I need to test it tonight.

I still do not understand how this solves the problem. When you move the mouse during scrolling and hit another widget it is hovered.
That is distracting.

But before hovering another widget you leave the knob widget which bypassed the solution here.
Is this an issue?

[ronso0]

(this reminds me to unset the cursor in LeaveEvent so it can't be hidden by hovering the knob during the timeout (when not scrolling))

done.

I think I'll also may implement lazy timer creation like for ControlPushButtonBehavior since the same reasoning applies to knobs, too.

mixxx/src/control/controlbehavior.h

Lines 149 to 156 in 28e8b3f

	// We create many hundreds of push buttons at Mixxx startup and most of them
	// never use their timer. Delay creation of the timer until it's needed.
	QTimer* getTimer() {
	if (m_pushTimer.isNull()) {
	m_pushTimer.reset(new QTimer());
	}
	return m_pushTimer.data();
	}

[ronso0]

When you move the mouse during scrolling and hit another widget it is hovered.
That is distracting.

I don't understand, please describe the distraction in that case.
Do you think users move the mouse wider than a knob widget while scrolling like mad?

Btw I think move events could of course be ignored while scrolling, though not while the cursor is still hidden some time after scrolling, because then I'd expect the cursor move again (like instant release after a drag event).

[daschuer]

I have just tested this PR and it works like described. Now I also understand the issue and how it is solved.

[ronso0]

ping @daschuer

[daschuer]

Sorry for the delay. A few more findings.

[daschuer]

Thank you. Looks and works good.