RFR: 8334874: Horizontal scroll events from touch pads should scroll the TabPane tabs

[Andy Goryachev]

On Mon, 24 Jun 2024 18:05:09 GMT, Jose Pereda <jpereda at openjdk.org> wrote:

> This PR considers the horizontal scroll events that can be generated on a trackpad, on an horizontally sided `TabPane` control (top or bottom), adding to the existing vertical scroll events from mouse wheel and trackpad, to scroll its tabs.
> 
> Therefore, scrolling a `TabPane` will behave in the same way that `ScrollBar` does regarding those same events and control orientation (vertical/horizontal).

modules/javafx.controls/src/main/java/javafx/scene/control/skin/TabPaneSkin.java line 947:

> 945:                     case BOTTOM:
> 946:                         // Consider vertical scroll events (dy > dx) from mouse wheel and trackpad,
> 947:                         // and horizontal scroll events from a trackpad (dx > dy)

Maybe we should explain why - to preserve the existing behavior with the mouse (scrolling up/down)?

The trackpad events can have both `dx` and `dy` of various magnitude, both non-zero, so the logic seems to me a bit contrived - like filtering some events, although at the end it still feels ok.

What do you think?

-------------

PR Review Comment: https://git.openjdk.org/jfx/pull/1486#discussion_r1651762899