Enum AccessPattern 

#[non_exhaustive]
pub enum AccessPattern {
    Sequential,
    Spatial,
}

The tile shape an op wants its input delivered in.

The scheduler negotiates tile shapes from this declaration (ADR-0003): runs of Sequential ops move full-width strips, matching how codecs produce and consume rows, while Spatial segments switch to square tiles to bound redundant border work. A rolling line-cache is inserted at the seam between the two. Declaring Spatial when Sequential would do costs throughput; declaring Sequential when the op actually reads neighbours is a correctness bug.

Shape, not order

This says nothing about the order tiles are produced in. An op that mirrors vertically reads no neighbours and wants full-width strips, so it is Sequential — even though it consumes those strips bottom-up.

Order is not declared at all: the scheduler derives it from Op::input_regions and inserts a materialization buffer only where a non-forward demand sequence meets a forward-only source (ADR-0009). Keeping order out of this enum is deliberate — it is a property of the seam between an op and its upstream, not of the op, so the same op streams or buffers depending on what it is connected to.

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.

Sequential

Each output pixel depends on input pixels from a single row.

Wants full-width strips. Pointwise ops (modulate, flatten, channel extraction) and row-preserving geometry remaps (crop, flop, flip) are sequential — including flip, which reverses row order but still reads one input row per output row.

Spatial

Output pixels depend on a neighbourhood spanning multiple input rows.

Wants square tiles. Convolution and resize with filter support are spatial.

Trait Implementations

impl Clone for AccessPattern

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for AccessPattern

impl Debug for AccessPattern

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

Formats the value using the given formatter.

impl Eq for AccessPattern

impl Hash for AccessPattern

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

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 AccessPattern

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for AccessPattern