Saving and loading splines

import sys

import numpy as np
import splinebox.basis_functions
import splinebox.spline_curves

We start by creating a random spline.

spline = splinebox.spline_curves.Spline(
    M=5, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.random.rand(5, 3)
)

Let’s save the spline:

spline.to_json("spline.json")

Here is what the json file looks like:

with open("spline.json") as f:
    sys.stdout.write(f.read())

{
  "version": 1,
  "M": 5,
  "basis_function": "B3",
  "closed": true,
  "control_points": [
    [
      0.6482332700676897,
      0.6219790425278798,
      0.6402812948349823
    ],
    [
      0.3474754414536124,
      0.8873718303900037,
      0.758105176439606
    ],
    [
      0.7638183052289742,
      0.14387029477108992,
      0.08608177147253715
    ],
    [
      0.15435784797203222,
      0.9770239843520149,
      0.6392729372020461
    ],
    [
      0.4550373627182125,
      0.7373554517392681,
      0.023833299095512794
    ]
  ]
}

Next, we will create a new spline based on the json file.

loaded_spline = splinebox.spline_curves.Spline.from_json("spline.json")

You can also save multiple splines in a single json file.

splines = []
for _ in range(3):
    spline = splinebox.spline_curves.Spline(
        M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.random.rand(4, 1)
    )
    splines.append(spline)

splinebox.spline_curves.splines_to_json("splines.json", splines)

Here is what a json file with multiple splines looks like:

with open("splines.json") as f:
    sys.stdout.write(f.read())

[
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.8830180891072925
      ],
      [
        0.5073507813658725
      ],
      [
        0.04069425045657815
      ],
      [
        0.16518186963706172
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.8661653835014783
      ],
      [
        0.48644274926755404
      ],
      [
        0.7979819406923181
      ],
      [
        0.35395702090370795
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.17272652503663666
      ],
      [
        0.1953362691364916
      ],
      [
        0.07310620008138724
      ],
      [
        0.19270424813793552
      ]
    ]
  }
]

Lastly, we load multiple splines from a single json file.

splines = splinebox.spline_curves.splines_from_json("splines.json")
print(splines)

[splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.88301809],
       [0.50735078],
       [0.04069425],
       [0.16518187]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.86616538],
       [0.48644275],
       [0.79798194],
       [0.35395702]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.17272653],
       [0.19533627],
       [0.0731062 ],
       [0.19270425]]))]