Struct ScrollSample 

pub struct ScrollSample {
    pub delta: ScrollDelta,
    pub position: Option<Point>,
    pub phase: ScrollPhase,
    pub source: ScrollSource,
    pub pointer: PointerInfo,
    pub modifiers: Modifiers,
}

One scroll sample as it enters the tree.

The unit WidgetTree::dispatch_scroll consumes.

Fields

delta: ScrollDelta

How far to scroll, in lines or pixels.

position: Option<Point>

Where the pointer was, in window-logical coordinates, when the scroll happened.

Some routes the scroll by hit test; None falls back to the hovered (else focused) widget. A wheel event has historically been None and stays that way, so a mouse routes exactly as before; a synthesised touch pan must carry a position, because a contact never writes hover and would otherwise route nowhere.

phase: ScrollPhase

Where in a continuous gesture this sample sits.

source: ScrollSource

What produced it.

pointer: PointerInfo

Who is pointing.

modifiers: Modifiers

Modifier keys held when the sample was produced. Ctrl-wheel-to-zoom reads this.

Implementations

impl ScrollSample

pub fn wheel(delta: ScrollDelta, modifiers: Modifiers, time: EventTime) -> Self

A discrete wheel notch from the mouse, routed by hover — exactly what WidgetEvent::Scroll meant before the touch programme.

pub fn at(self, position: Point) -> Self

This sample routed at position rather than by hover.

Trait Implementations

impl Clone for ScrollSample

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ScrollSample

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

Formats the value using the given formatter.