Crate uniform_cubic_splines[−][src]
Expand description
Uniform cubic spline interpolation & inversion.
This crate supports the following types of splines:
- B-spline
- Bezier
- Catmull-Rom
- Hermite
- Linear
- Power
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.
Cargo Features
The spline_inverse()
code will check if the knot vector is
monotonic in debug
builds. This only works in nightly
and is
behind a feature flag thus.
[dependencies]
uniform-cubic-splines = { version = "0.1.4", features = [ "unstable" ] }
The crate does not depend on the standard library (i.e. is marked
no_std
).
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::{
spline, spline_inverse, basis::CatmullRom
};
// 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.
Modules
Functions
As x
varies from 0
to 1
, this function returns the value
of a cubic interpolation of uniformly spaced knots
.
The input value x
will be clamped to the range [0, 1]
.
Computes the inverse of the spline()
function.
This returns the value x
for which spline(x)
would return y
.