Struct RubberBand 

pub struct RubberBand { /* private fields */ }

The iOS-style rubber-band scroll feel: a drag may pull the position past an edge, resisted by [OVERSCROLL_RESISTANCE], and nothing about a boundary is rejected. See the module docs for what the trait does not carry for this physics.

Implementations

impl RubberBand

pub fn new() -> RubberBand

A standalone rubber-band physics (no chained parent).

pub fn chain(self, parent: impl ScrollPhysics + 'static) -> RubberBand

Chain parent behind this physics, the module-wide composition convention (ScrollPhysics’ Chaining): every method this type does not override walks up to parent.

Trait Implementations

impl Debug for RubberBand

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

Formats the value using the given formatter.

impl Default for RubberBand

fn default() -> RubberBand

Returns the “default value” for a type.

impl ScrollPhysics for RubberBand

fn apply_physics_to_user_offset( &self, metrics: &ScrollMetrics, offset: f64, ) -> f64

The past-edge portion of the drag is scaled by [OVERSCROLL_RESISTANCE]; the portion that keeps the position inside [min, max] passes through untouched. A delta straddling an edge is split between the two rather than resisted whole.

fn apply_boundary_conditions( &self, _metrics: &ScrollMetrics, _value: f64, ) -> f64

Nothing is ever rejected: a rubber-band surface holds an out-of-range position for as long as the finger asks it to, and the release-settle (not a boundary rule) is what brings it back.

fn create_ballistic_simulation( &self, _metrics: &ScrollMetrics, _velocity: f64, ) -> Option<Box<dyn Simulation>>

No generic ballistic simulation — both scroll surfaces keep their own hand-rolled fling (fling_decay/fling_displacement) and release-settle for this physics, which is exactly what makes installing it a no-op on the shipped feel. A None here is the documented contract for “the widget’s legacy path owns post-release motion”, not a gap to fill in later by this type: a physics that does want the generic driver returns a Simulation, and the widget then drives that instead.

fn carried_momentum(&self, _existing_velocity: f64) -> f64

A re-fling during live motion starts cold, matching both widgets’ shipped behavior (a new Down kills the fling outright).

fn should_accept_user_offset(&self, _metrics: &ScrollMetrics) -> bool

Always true, deliberately overriding the trait’s has-scrollable-content default: a ScrollView/ListView whose content fits its viewport still rubber-bands under the finger today, and matching the shipped feel wins over the more principled default.

fn parent(&self) -> Option<&dyn ScrollPhysics>

The chained parent physics, if this one was built via chain(...). None for a physics built standalone (the chain’s root).

fn min_fling_velocity(&self) -> f64

The minimum release speed that starts a fling.

fn max_fling_velocity(&self) -> f64

The fastest fling speed this physics honors.

fn tolerance_for(&self, metrics: &ScrollMetrics) -> Tolerance

The velocity/distance tolerance a ballistic simulation settles within.

fn spring(&self) -> SpringDescription

The spring a bounce-back/snap simulation is built from.