[Proposal] center elements for scrollTo

[RobbieTheWagner]

Currently, we use https://developer.mozilla.org/en-US/docs/Web/API/Element/scrollIntoView with the default options, which scrolls until the element is aligned with the top of the viewport. This is configurable, and there appears to be an option where the element is centered instead. Perhaps centered would be a more sane default, and not so extreme? We could also make this configurable and allow the user to pass top, bottom, center etc. or possible let them pass options directly to the call to scrollIntoView.

@chuckcarpenter thoughts?

cc @hheexx

[hheexx]

I have checked the APIs.
Passing scrollIntoViewOptions from tour would be very easy for you to implement and it would be much better then now. But not perfect.
I recommend you implement this first.

tour.addStep('step5', {
			title: 'Tutorial',
			text: 'some text...',
			attachTo: '#element',
			scrollTo: {behavior: "smooth", block: "center"},
			buttons: [
				{ text: 'Off', action: tour.cancel },
				{ text: 'Next', action: tour.next }
			]
		});

Perfect solution you can add later is scrolling element to bottom 1/3 of the screen and then showing tooltip in the top 2/3 of the screen.
The most sexy would be to scroll element to the center (you can use code above to do it), then wait like 100ms, then scroll element a little bit more down to bottom part of screen, and then tooltip faces in in the top part of the screen.

What do you think?

[RobbieTheWagner]

@hheexx

Passing scrollIntoViewOptions from tour would be very easy for you to implement and it would be much better then now.

If it is easy to implement, would you like to submit a PR for it? I think having scrollTo accept true to keep the behavior the same as now or allowing passing options like {behavior: "smooth", block: "center"}, would be a good API.

[hheexx]

Here: #401

I just finished but now I found out that scrollIntoViewOptions is not very vell supported. Safari still does not support it.
https://caniuse.com/#feat=scrollintoview

btw there is polyfill http://iamdustan.com/smoothscroll/

not sure what to do.

[RobbieTheWagner]

We can use the polyfill. I will work on this implementation.