bug#50269: 27.2; Request: use GTK continuous scroll events for smooth touchpad scrolling

[Alexander Huntley <huntley.alexander@gmail.com>]

> We are probably having communication difficulties due to terminology
> you are using.  pixel-scroll-mode doesn't work on line granularity, it
> actually shifts the display one pixel at a time.  If you scroll by
> enough pixels so that the sum total of those pixels amounts to one
> line, pixel-scroll-mode resets the display shift offset to zero and
> scrolls the display by one full line, then it keeps shifting one pixel
> at a time.
>
> Given this description of how pixel-scroll-mode works, what exactly
> would you like to change?
>
> Or maybe looking at this from a different angle: how does the behavior
> you'd like to see differ from what pixel-scroll-mode produces?
pixel-scroll-mode may shift the display one pixel at a time, but it
also "snaps" the display to certain larger intervals, (integer numbers
of lines).

This snapping makes the scrolling jerkier than it needs to be on
touchpads.

If we could use the more precise/frequent data actually coming from
the touchpad, then the user could control the scrolling more precisely:
instead of scrolling by n lines, the user could scroll by as little
as a single pixel at a time.