How to create a scrollbar

[franko]

I was working on a simple application and I would really need to have a scrollbar to move around inside big file and display some file-based content on and uiArea.

The uiScollingArea is not an option because it required to draw the whole image and it will be too inefficient, I really need a scrollbar.

I understood that currently there are no scrollbars in libui but they exists in GTK+ with some simple APIs. As for windows I don't know exactly but I guess they should exists.

As a last resort I may implement scrollbars in libui by myself but I would like to have some advice.
Any specific reason they are not already in libui ?
Some idea about how to implement them in Windows ?

If other people are interested too I would like to collaborate to make a good implementation.

[NoraCodes]

I think this is the same as #178

[rubyFeedback]

Super-hard to find documentation about this.

Perhaps a standalone example that shows how scrolling areas work could
help. The ruby examples in libui currently (August 2021) also don't have
a working example.

[rubyFeedback]

I should also explain my use case.

I am porting ruby-gtk3 widgets. One widget had 600 buttons - one
button for each local song. On click action I simply use mpv to
play it.

In the ruby-gtk3 widget I put this into a scrollbar-widget. I assume
this is a common use case for long areas or wrapped areas.