Struct ViewportWidget 

pub struct ViewportWidget { /* private fields */ }

The retained widget for a CustomScrollView: the children’s pods and what the last layout decided for each, the scroll position, and the shared scroll core (the module docs).

Implementations

impl ViewportWidget

pub fn offset(&self) -> f64

The current scroll position (in range unless a drag, settle or simulation holds it past an edge).

pub fn max_offset(&self) -> f64

The largest in-range scroll position: the children’s summed scroll extent less the viewport extent, never negative.

pub fn axis(&self) -> ScrollAxis

The axis this viewport scrolls along.

pub fn sliver_count(&self) -> usize

How many children the viewport holds.

pub fn sliver_geometry(&self, index: usize) -> Option<SliverGeometry>

The geometry child index reported from the last layout — the box adapter’s geometry for a child laid out as a box — or None past the last child.

pub fn is_flinging(&self) -> bool

Whether post-release motion is in flight (a fling or a simulation).

Trait Implementations

impl Widget for ViewportWidget

fn layout(&mut self, ctx: &mut LayoutCtx<'_>, bc: &BoxConstraints) -> Size

Choose a size within bc and return it. The chosen size must satisfy bc (callers may additionally clamp via BoxConstraints::constrain).

fn paint(&mut self, ctx: &mut PaintCtx<'_>, scene: &mut dyn PaintScene)

Emit draw commands for this widget into scene.

fn event(&mut self, ctx: &mut EventCtx<'_>, event: &InputEvent) -> EventResult

Handle an input event, optionally mutating application state through ctx and reporting whether it was consumed.

fn semantics(&self, ctx: &mut SemanticsCtx)

Contribute this widget’s accessibility node(s) into ctx.

fn visit_children(&self, visitor: &mut dyn FnMut(&ChildPod))

Visit this widget’s owned ChildPods, in declaration (paint) order — the read-only seam that makes the retained hierarchy enumerable.

fn type_name(&self) -> &'static str

This widget’s concrete type name, for read-only tooling.

fn as_sliver(&mut self) -> Option<&mut (dyn SliverWidget + 'static)>

This widget as a sliver, if it speaks the sliver protocol — the opt-in seam a scrolling viewport lays its children out through (see crate::sliver and ChildPod::layout_sliver_child).