Struct RadiusLaw 

pub struct RadiusLaw { /* private fields */ }

A composable radius law over cumulative abscissa [0, total_length].

Construction validates every input (refuse-or-exact: non-positive radii, non-positive lengths, and non-monotone interpolation abscissas are named errors); a constructed law is deterministic and cheap to evaluate.

Implementations

impl RadiusLaw

pub fn constant(length: f64, radius: f64) -> Result<Self, String>

A constant law: radius everywhere on [0, length].

pub fn from_vertex_radii( edge_lengths: &[f64], vertex_radii: &[f64], ) -> Result<Self, String>

The per-vertex chain model: radius vertex_radii[i] at chain vertex i, smoothly interpolated along the chain. edge_lengths[k] is the arc length of chain edge k, so the abscissa breakpoints sit at the chain’s edge junctions; vertex_radii needs exactly one entry per vertex (edge_lengths.len() + 1). Interpolation is monotone C1 (PCHIP): every vertex radius is met exactly and the law never overshoots the given radii.

pub fn from_segments(segments: &[LawSegment]) -> Result<Self, String>

Compose a law from consecutive segments with smooth junction transitions (see the module docs for the transition model).

pub fn total_length(&self) -> f64

Total abscissa length of the law’s domain.

pub fn radius_at(&self, s: f64) -> f64

Evaluate the radius at abscissa s (clamped into [0, total_length]).

pub fn radius_at_fraction(&self, fraction: f64) -> f64

Evaluate at normalized abscissa fraction ∈ [0, 1] of the domain.

pub fn max_second_derivative(&self, s_a: f64, s_b: f64) -> f64

Upper bound of |d²radius/ds²| over [s_a, s_b], used by callers to derive a sampling density from the law’s curvature (piecewise-linear interpolation error of a C1, piecewise-C2 function over step h is at most h²·max|r''|/8). Per piece the bound is exact-family: the second derivative of a degree ≤ 5 piece is a cubic, and the maximum absolute value of a polynomial is bounded by the maximum absolute Bernstein coefficient (convex-hull property). Pieces partially overlapping the query span use their whole-piece bound (conservative).

Trait Implementations

impl Clone for RadiusLaw

fn clone(&self) -> RadiusLaw

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RadiusLaw

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

Formats the value using the given formatter.