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": [
    [
      0.5144201630727383,
      0.6837616758929493,
      0.37639459594499336
    ],
    [
      0.628020510946427,
      0.019957841398765885,
      0.8635382481704144
    ],
    [
      0.42195905847912507,
      0.8974321758328678,
      0.6346325161260943
    ],
    [
      0.7400365415483713,
      0.2624120256978184,
      0.6911393994980407
    ],
    [
      0.22352311073390785,
      0.698768384315137,
      0.5694585198357389
    ]
  ]
}

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": [
      [
        0.09628988553057571
      ],
      [
        0.2582941867684798
      ],
      [
        0.2547254311149839
      ],
      [
        0.2199104892862188
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.1278901570169949
      ],
      [
        0.6145707429150035
      ],
      [
        0.19691739565588706
      ],
      [
        0.8833503881032535
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.6449590718016677
      ],
      [
        0.8443034834196623
      ],
      [
        0.5898649561139061
      ],
      [
        0.5601493699786311
      ]
    ]
  }
]

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([[0.09628989],
       [0.25829419],
       [0.25472543],
       [0.21991049]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.12789016],
       [0.61457074],
       [0.1969174 ],
       [0.88335039]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.64495907],
       [0.84430348],
       [0.58986496],
       [0.56014937]]))]