QMLDemo: improve OrientationToggleButton touch friendlyness

[Swiftb0y]

The previous implementation was hard to use on a touchscreen
because the surface where it was touching was very small.
The new version makes use of a slider internally which allows
the control to be changed more intiutively by swiping.

[Holzhaus]

Good idea, but this does not work. If I play deck 1, move the crossfader to the right and change the channel orientation, I still can't hear the deck. This is because you never actually set a value on the control proxy, just read it.

[Holzhaus]

Obviously, you can't add value: orientationSlider.value to the control proxy because that would create an endless binding loop.

Instead, you only want to update the CO value when the slider was moved by the user, not on every value change.

Try this:

Suggested change

	snapMode: Slider.SnapOnRelease
	snapMode: Slider.SnapOnRelease
	onMoved: control.value = value

Didn't test this, but it should work.

[Swiftb0y]

Thanks, I thought I had figured it out but it seems like I didn't. Not sure onMoved will work because it might fire before releasing the control, but I'll try to figure something out.

[Swiftb0y]

Turns out using onMoved causes some weird issues where the visualposition and the value of the slider get out of sync. I'll have to think of another workaround...

[Holzhaus]

I investigated a bit (using console.warn(value) 😉), and this should work.

Suggested change

	snapMode: Slider.SnapOnRelease
	snapMode: Slider.SnapOnRelease
	onMoved: {
	// The slider's `value` is not updated until after the move ended,
	// so we need to calculate the value position ourselves here.
	control.value = Math.round(visualPosition * (to - from));
	}

[Swiftb0y]

Thanks. I don't know when I'll be able to get back on this though.

[Swiftb0y]

Should work now.

[coveralls]

Pull Request Test Coverage Report for Build 1033210008

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.004%) to 28.63%

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Totals
Change from base Build 1025553951:	0.004%
Covered Lines:	20090
Relevant Lines:	70170

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💛 - Coveralls

[Holzhaus]

Thanks, it works. But IMHO util.js makes the much more complicated than it needs to be.

[Holzhaus]

Why is this a utility function? If I use this function for two unrelated values, the result is wrong, so it's not reusable.

[Swiftb0y]

Yes, it is very primitive, I'm aware. It's not supposed to be perfect but just generally make sure that code that gets called repeatedly can debounce a bit so to speak.

[Holzhaus]

Why not just val != control.value? This utility function makes it harder to understand what happens. It's also not reusable because it uses a global mutable variable (evil!).

[Swiftb0y]

Thats a good idea actually. How did I not think of that.

[Holzhaus]

LGTM, thank you!