Enum PenBatching 

#[non_exhaustive]
pub enum PenBatching {
    PerPacket,
    Coalesce,
}

How a drained pen batch reaches the tree.

A digitizer runs at 200-360 Hz and a window’s message rate does not, so one poll_pen drain routinely holds several packets. Both answers to “what does the tree see?” are defensible and the trade is real, which is why this is a knob rather than a decision baked in:

• PerPacket spends a whole tree dispatch — hit test, arbitration turn, handler walk — on every packet. Nothing is lost and nothing is coalesced; it is what the pen path has always done.
• Coalesce spends one dispatch per drain and hands the intermediate positions over as PointerSample::coalesced, each keeping its own time and its own axes. A surface that reads EventContext::coalesced sees exactly the same positions; one that does not sees fewer moves.

Transitions are never folded. Down, Up, a button change and proximity enter/leave each keep their own sample under either mode, so no recognizer sees a different sequence — only the number of PointerMoves between two transitions changes.

Four of those five the fold can see for itself, because all it tests is the phase and the button: Down and Up are not Move, a button change reports a button, and proximity leave is a PointerPhase::Cancel, so it breaks a run for free. The fifth it cannot, and that one is handled by name rather than by luck: proximity enter has no phase of its own — it is carried as a move with nothing held — so poll_pen pins it, because folding it away would not cost a PointerMove but a PointerEnter: the tree derives the hover owner, the cursor and the tooltip dwell from a sample’s position and never from its batched list, and a tool that came into range over one widget and hovered onto another inside one drain would otherwise never enter the first.

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.

PerPacket

One PointerSample per packet. The default, and what the pen path did before this existed.

Coalesce

One sample per transition; the pure-motion packets between two transitions ride in PointerSample::coalesced.

Trait Implementations

impl Clone for PenBatching

fn clone(&self) -> PenBatching

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for PenBatching

impl Debug for PenBatching

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

Formats the value using the given formatter.

impl Default for PenBatching

fn default() -> PenBatching

Returns the “default value” for a type.

impl Eq for PenBatching

impl PartialEq for PenBatching

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for PenBatching