Struct Scrollbar 

pub struct Scrollbar { /* private fields */ }

A single-axis scrollbar interaction model.

Construct one per axis (Scrollbar::vertical / Scrollbar::horizontal), keep it alongside the owning widget’s offset, and drive it from the widget’s event handler:

// press
match bar.press(track, metrics, cursor) {
    PressOutcome::Thumb   => { /* dirty + capture */ }
    PressOutcome::Page(o) => { self.set_offset(o); }
    PressOutcome::Miss    => { /* fall through */ }
}
// move
if let Some(o) = bar.drag_to(track, metrics, cursor) { self.set_offset(o); }
// release
bar.release();

Implementations

impl Scrollbar

pub fn vertical() -> Scrollbar

A vertical bar (thumb travels along Y, lives on the right edge).

pub fn horizontal() -> Scrollbar

A horizontal bar (thumb travels along X, lives on the bottom edge).

pub fn with_min_thumb(self, px: f64) -> Scrollbar

Override the minimum thumb length (default MIN_THUMB_LEN).

pub fn is_vertical(&self) -> bool

pub fn is_dragging(&self) -> bool

Whether a thumb drag is currently in progress.

pub fn is_hovered(&self) -> bool

Whether the pointer is currently over the thumb.

pub fn is_active(&self) -> bool

Whether the thumb should render in its brightened state (hovered or dragging).

pub fn draw( &self, scene: &mut Scene, transform: Affine, track: Rect, metrics: ScrollMetrics, theme: &Theme, focused: bool, )

Paint the shared quiet thumb for hosts with a custom content viewport. Geometry is identical to pointer hit-testing and follows the host’s metrics.

pub fn track_in(&self, lane: Rect, theme: &Theme) -> Rect

The track this bar takes in lane, the strip a scroll owner keeps free on its trailing (or bottom) edge (metrics.scrollbar_gutter wide): the thumb thickness (metrics.scroll_thumb) centred across the lane, inset by the same margin at both ends. Painted hosts use it so their bars sit where a Scrollable’s do.

pub fn thumb_rect(&self, track: Rect, m: ScrollMetrics) -> Option<Rect>

The thumb rect within track for the given metrics, or None when there’s no meaningful content to represent. The owner is responsible for only supplying a track when the bar is actually shown (content overflows); this method does not re-check overflow so the thumb stays visible while a drag/clamp settles at an edge.

pub fn set_hover(&mut self, hovered: bool) -> bool

Set the hover state directly; returns true when it changed (so the owner can schedule a redraw only on an edge).

pub fn update_hover( &mut self, track: Rect, m: ScrollMetrics, cursor: Point, ) -> bool

Recompute hover from the cursor against the thumb; returns true when the hover state changed. A no-op while dragging (the thumb stays “hot”).

pub fn press( &mut self, track: Rect, m: ScrollMetrics, cursor: Point, ) -> PressOutcome

Hit-test a press against the bar and, if it lands on the thumb, begin a drag. See PressOutcome.

pub fn drag_to( &self, track: Rect, m: ScrollMetrics, cursor: Point, ) -> Option<f64>

Map the live cursor to an absolute offset for the active drag, or None when no drag is in progress. The thumb travels track_len - thumb_len px across the full content range, so that ratio converts a cursor delta into a content delta. The result is clamped to [0, max_scroll].

pub fn release(&mut self) -> bool

End any active drag; returns true when a drag was actually in progress (so the owner can mark itself dirty / release capture).

Trait Implementations

impl Clone for Scrollbar

fn clone(&self) -> Scrollbar

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Scrollbar

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

Formats the value using the given formatter.

impl Copy for Scrollbar