Package catmullrom implements the centripetal Catmull-Rom spline and calculates points of a 2D spline curve given a series of control points.
Add it to a module as a dependency via:
go get github.com/fzipp/catmullrom
A single spline requires four control points (p0, p1, p2, p3). The resulting interpolated points of the spline curve are between the second and the third control point (p1 and p2).
package main
import (
"fmt"
"github.com/fzipp/catmullrom"
)
func main() {
p := []catmullrom.Point{
{X: 0, Y: 2.5},
{X: 2, Y: 4},
{X: 3, Y: 2},
{X: 4, Y: 1.5},
}
curve := catmullrom.Spline(p[0], p[1], p[2], p[3], 100, 0.5)
for _, point := range curve {
fmt.Printf("%v\t%v\n", point.X, point.Y)
}
}Output:
2 4
2.014365414796725 3.9961683757388826
2.0285086520907125 3.991519010789197
2.0424338917428546 3.986066863428536
[...]
2.9631689321190793 2.0405052334680907
2.9752654723162837 2.026380248925892
2.9875411016562947 2.012873518343997
3 2
A spline chain goes through an arbitrary number of control points, including the first and the last control point.
package main
import (
"fmt"
"github.com/fzipp/catmullrom"
)
func main() {
controlPoints := []catmullrom.Point{
{X: 0, Y: 2.5},
{X: 2, Y: 4},
{X: 3, Y: 2},
{X: 4, Y: 1.5},
{X: 5, Y: 6},
{X: 6, Y: 5},
{X: 7, Y: 3},
{X: 9, Y: 1},
{X: 10, Y: 2.5},
{X: 11, Y: 7},
{X: 9, Y: 5},
{X: 8, Y: 6},
{X: 7, Y: 5.5},
}
curve := catmullrom.SplineChain(controlPoints, 100, 0.5)
for _, point := range curve {
fmt.Printf("%v\t%v\n", point.X, point.Y)
}
}Output:
0 2.5
0.020250950290489646 2.5153391496514774
0.040597763611450566 2.531045909751864
0.06103744424317995 2.5471087924746265
[...]
7.030349491470336 5.5157336988112
7.0202228847077075 5.5103624536889235
7.01010628000193 5.505116539771162
7 5.5
Visualized curve:
This project is free and open source software licensed under the BSD 3-Clause License.