1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79
use core::ops::{Mul, Sub}; use cast_trait::Cast; use num_traits::{FromPrimitive, One, Zero}; use cubic::cubic; use linear::linear; use quadratic::quadratic; #[inline] pub fn n<T, F>(points: &[T], t: &F) -> T where T: Clone + Cast<F> + Zero, F: Clone + One + Zero + FromPrimitive + PartialOrd + Cast<T> + Sub<F, Output = F> + Mul<F, Output = F>, for<'a, 'b> &'a F: Sub<&'b F, Output = F> + Mul<&'b F, Output = F>, { if t <= &F::zero() { match points.len() { 0 => T::zero(), _ => points[0].clone(), } } else if t >= &F::one() { match points.len() { 0 => T::zero(), n => points[n - 1].clone(), } } else { match points.len() { 0 => T::zero(), 1 => points[0].clone(), 2 => linear(&points[0], &points[1], t), 3 => cubic(&points[0], &points[1], &points[2], t), 4 => quadratic(&points[0], &points[1], &points[2], &points[3], t), n => casteljau(points, n - 1, 0, t), } } } #[inline] fn casteljau<T, F>(points: &[T], i: usize, j: usize, t: &F) -> T where T: Clone + Cast<F>, F: Clone + One + Zero + PartialOrd + Cast<T> + Sub<F, Output = F> + Mul<F, Output = F>, for<'a, 'b> &'a F: Sub<&'b F, Output = F> + Mul<&'b F, Output = F>, { if i == 0_usize { points[j].clone() } else { let p0 = casteljau(points, i - 1, j, t); let p1 = casteljau(points, i - 1, j + 1, t); let x0 = p0.clone().cast(); let x1 = p1.clone().cast(); ((F::one() - t.clone()) * x0 + t.clone() * x1).cast() } } #[test] fn test_n() { assert_eq!(n::<isize, f32>(&[], &0.0), 0); assert_eq!(n::<isize, f32>(&[], &0.5), 0); assert_eq!(n::<isize, f32>(&[], &1.0), 0); assert_eq!(n(&[0, 150, 200, 0], &0.25), 91); assert_eq!(n(&[0, 150, 200, 0], &0.5), 131); assert_eq!(n(&[0, 150, 200, 0], &0.75), 105); assert_eq!(n(&[0, 150, 200, 50, 0], &0.25), 106); assert_eq!(n(&[0, 150, 200, 50, 0], &0.5), 124); assert_eq!(n(&[0, 150, 200, 50, 0], &0.75), 69); }