Enum CancelReason 

#[non_exhaustive]
pub enum CancelReason {
    Platform,
    WindowDeactivated,
    Occluded,
    ModalOpened,
    SubtreeParked,
    WidgetDestroyed,
    CaptureOrphaned,
    OsDragStarted,
    ExternalDndTakeover,
    PeerClaimed,
    OverlayDismissed,
    MultiContactIgnored,
    ContactCapExceeded,
    PalmRejected,
    Deactivated,
}

Why a pointer interaction was revoked.

Declared in full here so the taxonomy is one enumeration rather than a growing set of booleans, and so a consumer can match on it exhaustively. Every variant reaches a widget through the one funnel, WidgetTree::cancel_pointer, and is delivered as a WidgetEvent::PointerCancel. A handful name a producer whose own package has not landed and are marked as such below; docs/touch-and-pen.md §3.3 carries the full table of who raises each, who receives it, and what the widget must do about it.

#[non_exhaustive]: the taxonomy is expected to grow as backends reveal revocation paths Teksilo has not met.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Platform

The OS itself revoked the pointer (a PointerCaptureLost, a wl_touch.cancel, a compositor grab).

WindowDeactivated

The window lost focus mid-interaction.

Occluded

The window became fully occluded mid-interaction. Reserved for the platform layer’s occlusion path.

ModalOpened

A modal surface opened over the interaction.

SubtreeParked

The interacting subtree went dormant (a Switcher branch was parked, a tab was switched away from).

WidgetDestroyed

The interacting widget was destroyed.

CaptureOrphaned

The widget holding the pointer capture went away, leaving the capture with no owner.

OsDragStarted

A native OS drag started from this press, so the in-app interaction ends.

ExternalDndTakeover

An external (OS) drag-and-drop session took the pointer over. Reserved for the inbound external-DnD path.

PeerClaimed

Another member of the gesture sequence won arbitration, so this one is revoked.

OverlayDismissed

The overlay the interaction lived in was dismissed under it.

MultiContactIgnored

A second contact arrived on a surface that handles only one, so the interaction is abandoned rather than misread. Reserved for MultiContact::First.

ContactCapExceeded

More simultaneous contacts arrived than the pointer table holds. Refused at PointerTable::begin, before any event exists, so no widget is told.

PalmRejected

The contact was classified as a palm rather than a deliberate touch. Refused at PointerTable::begin, before any event exists, so no widget is told.

Deactivated

A catch-all for a deactivation that fits none of the above. Prefer a specific variant; this one exists so a caller is never forced to lie.

Trait Implementations

impl Clone for CancelReason

fn clone(&self) -> CancelReason

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for CancelReason

impl Debug for CancelReason

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

Formats the value using the given formatter.

impl Eq for CancelReason

impl PartialEq for CancelReason

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for CancelReason