Struct OngoingScroll 

pub struct OngoingScroll { /* private fields */ }

Keeps a scroll gesture on one axis, so a mostly vertical swipe does not drift sideways.

Keep one OngoingScroll per scroll container and pass each scroll event through OngoingScroll::filter before applying it. GPUI’s div element keeps one for each scrollable container.

Implementations

impl OngoingScroll

pub fn filter(&mut self, delta: &mut Point<Pixels>, touch_phase: TouchPhase)

Zeroes the component of delta off the gesture’s dominant axis.

The first event of a gesture picks the axis with the larger absolute movement. Later events keep that axis until the movement clearly favors the other axis, by at least 1.9 times and at least 6 pixels, and then the gesture is free on both axes again. A gesture starts again at a TouchPhase::Started event, or after 28 milliseconds without an event, which covers platforms that only send TouchPhase::Moved. A TouchPhase::Ended or TouchPhase::Cancelled event clears the gesture.

delta is in logical pixels and is changed in place. A zero delta on TouchPhase::Started clears the gesture, and other zero deltas are ignored.

Examples

use gpui::{OngoingScroll, Pixels, Point, TouchPhase, point, px};

let mut scroll = OngoingScroll::default();
let mut delta: Point<Pixels> = point(px(10.), px(2.));
scroll.filter(&mut delta, TouchPhase::Started);
// The horizontal movement dominates, so the vertical part is dropped.
assert_eq!(delta, point(px(10.), px(0.)));

Gestures are delimited by their touch phase when available, with a timeout fallback for platforms that only emit TouchPhase::Moved.

Trait Implementations

impl Clone for OngoingScroll

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for OngoingScroll

impl Debug for OngoingScroll

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for OngoingScroll

fn default() -> Self

Returns the “default value” for a type.