Enum zng::scroll::ScrollFrom

pub enum ScrollFrom {
    Var(Px),
    VarTarget(Px),
    Rendered(Px),
}

Defines a scroll delta and to what value source it is applied.

Scrolling can get out of sync depending on what moment and source the current scroll is read, the offset vars can be multiple frames ahead as update cycles have higher priority than render, some scrolling operations also target the value the smooth scrolling animation is animating too, this enum lets you specify from what scroll offset a delta must be computed.

Variants

Var(Px)

Scroll amount added to the offset var current value, if smooth scrolling is enabled this can be a partial value different from VarTarget.

Operations that compute a scroll delta from the offset var must use this variant otherwise they will overshoot.

VarTarget(Px)

Scroll amount added to the value the offset var is animating too.

Operations that accumulate a delta (line-up/down) must use this variant otherwise they will undershoot.

This is the same as Var if smooth scrolling is disabled.

Rendered(Px)

Scroll amount added to the offset already rendered, this can be different from the offset var as multiple events and updates can happen before a pending render is applied.

Operations that compute a scroll offset from widget bounds info must use this variant otherwise they will overshoot.

Trait Implementations

impl Clone for ScrollFrom

fn clone(&self) -> ScrollFrom

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ScrollFrom

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ScrollFrom

fn deserialize<__D>( __deserializer: __D, ) -> Result<ScrollFrom, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Hash for ScrollFrom

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for ScrollFrom

fn eq(&self, other: &ScrollFrom) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for ScrollFrom

fn serialize<__S>( &self, __serializer: __S, ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for ScrollFrom

impl StructuralPartialEq for ScrollFrom