Struct Location 

pub struct Location { /* private fields */ }

A placement: a chain of (datum, power) pairs.

Applied left to right, so the first entry is the outermost transform. An empty chain is the identity.

Powers are integers, so a datum applied twice costs one entry rather than two, and its inverse is the same entry with the sign flipped. Equality and hashing are structural: two locations agree when their chains match entry for entry. Deliberately not a comparison of the composed transforms; that would be a tolerance question, and the answer would depend on rounding rather than on what the model says.

Implementations

impl Location

pub fn identity() -> Self

The identity placement.

pub fn of(datum: DatumId) -> Self

A placement of one datum, applied once.

pub fn powered(datum: DatumId, power: i32) -> Self

A placement of one datum, applied power times.

A power of zero gives the identity; a negative power gives the inverse.

pub fn is_identity(&self) -> bool

Whether this is the identity.

pub fn ends_with(&self, inner: &Self) -> bool

Whether this placement is inner with further placements outside it: inner’s chain is this chain’s tail.

pub fn chain(&self) -> &[(DatumId, i32)]

The chain, outermost entry first.

pub fn depth(&self) -> usize

Number of entries.

pub fn then(&self, inner: &Self) -> Self

This placement followed by inner.

outer.then(inner) applies inner first, then outer, the same order as transform composition, so a sub-shape’s placement composed with its parent’s reads the way the tree does.

Adjacent entries naming the same datum are merged by adding their powers, and an entry whose power reaches zero is dropped. That keeps a chain from growing without bound as a placement is composed and undone repeatedly, and it is what makes a.then(a.inverted()) come out exactly equal to the identity rather than merely close to it.

pub fn inverted(&self) -> Self

The inverse placement.

Exact: the chain reverses and every power negates. No matrix is inverted, so l.then(&l.inverted()) is the identity structurally, not approximately.

pub fn composed(&self, store: &DatumStore) -> OgeomResult<Transform>

The composed transform.

Errors

OgeomError::Dangling if the chain names a datum the store does not hold, and OgeomError::Numeric if a negative power requires inverting a degenerate transform.

pub fn preserves_handedness(&self, store: &DatumStore) -> OgeomResult<bool>

Whether the composed transform preserves handedness.

A shape placed by a handedness-reversing location has to have its orientation flipped to stay consistent, or a mirrored solid ends up inside out.

Errors

As Location::composed.

pub fn is_same_placement( &self, other: &Self, store: &DatumStore, tol: Tolerances, ) -> OgeomResult<bool>

Whether two placements put a shape in the same position.

Falls back to comparing the composed transforms, which costs more than PartialEq and answers a different question: two chains built by different routes can describe the same placement.

Errors

As Location::composed.

pub fn kind(&self, store: &DatumStore) -> OgeomResult<TransformKind>

The kind of the composed transform, for dispatch.

Errors

As Location::composed.

Trait Implementations

impl Clone for Location

fn clone(&self) -> Location

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Location

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

Formats the value using the given formatter.

impl Default for Location

fn default() -> Location

Returns the “default value” for a type.

impl Eq for Location

impl Hash for Location

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 Location

fn eq(&self, other: &Location) -> 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 StructuralPartialEq for Location