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": [
    [
      0.9968825081062371,
      0.03794235554933434,
      0.3192220425345669
    ],
    [
      0.39137010900821956,
      0.41328549358889843,
      0.7895119422658325
    ],
    [
      0.8868419791976561,
      0.15472032511365008,
      0.477087684545067
    ],
    [
      0.6819968988926697,
      0.6984765805326295,
      0.1570127727788574
    ],
    [
      0.5924394481308163,
      0.48173718872518334,
      0.2520381171841275
    ]
  ]
}

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": [
      [
        0.3025477615480596
      ],
      [
        0.7542100155185272
      ],
      [
        0.22041016749746345
      ],
      [
        0.30273800694331965
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.954899863687714
      ],
      [
        0.3152836480786152
      ],
      [
        0.15743166310401469
      ],
      [
        0.3454637849566269
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.21857872700631287
      ],
      [
        0.4435889346709041
      ],
      [
        0.2981979141658898
      ],
      [
        0.4026871330443029
      ]
    ]
  }
]

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([[0.30254776],
       [0.75421002],
       [0.22041017],
       [0.30273801]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.95489986],
       [0.31528365],
       [0.15743166],
       [0.34546378]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.21857873],
       [0.44358893],
       [0.29819791],
       [0.40268713]]))]