Crate uniform_cubic_splines

Source
Expand description

Uniform cubic spline interpolation & inversion.

This crate supports the following types of splines:

The crate uses generics to allow interpolation of any type for which certain traits are defined.

I.e. you can use this crate to interpolate splines in 1D, 2D, 3D, etc.

§Example

Using a combination of spline() and spline_inverse() it is possible to compute a full spline-with-non-uniform-abscissæ:

use uniform_cubic_splines::prelude::*;

// We want to evaluate the spline at knot value 0.3.
let x = 0.3;

// The first and last points are never interpolated.
let knot_spacing = [0.0, 0.0, 0.1, 0.3, 1.0, 1.0];
let knots = [0.0, 0.0, 1.3, 4.2, 3.2, 3.2];

let v = spline_inverse::<CatmullRom, _>(x, &knot_spacing).unwrap();
let y = spline::<CatmullRom, _, _>(v, &knots);

assert!(y - 4.2 < 1e-6);

§Background

The code is a Rust port of the resp. implementations found in the Open Shading Language C++ source.

If you come from a background of computer graphics/shading languages used in offline rendering this crate should feel like home.

§no-std

The crate does not depend on the standard library (i.e. is marked no_std).

§Cargo Features

  • monotonic_check — The spline_inverse()/spline_inverse_with() code will check if the knot vector is monotonic (enabled by default).

Modules§

basis
prelude

Macros§

len_check

Structs§

SplineInverseOptions
Options for spline_inverse_with() function.

Functions§

is_len_okDeprecated
Returns true if a knots slice you want to feed into spline() has the correct length for the choosen Basis.
spline
As x varies from 0 to 1, this function returns the value of a cubic interpolation of uniformly spaced knots.
spline_inverse
Computes the inverse of the spline() function.
spline_inverse_with
Computes the inverse of the spline() function with control over iterations & precision via resp. SplineInverseOptions.