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": [
    [
      0.22866620252612857,
      0.4262301500912308,
      0.7174008985325085
    ],
    [
      0.3205657811855481,
      0.6650795852313316,
      0.45388648459309455
    ],
    [
      0.49380268195361454,
      0.7198426340516233,
      0.03931323178435275
    ],
    [
      0.1934855389364072,
      0.6352434520200382,
      0.14537730514805758
    ],
    [
      0.31920255869302017,
      0.7761925273284254,
      0.36339136074660905
    ]
  ]
}

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": [
      [
        0.918947140035338
      ],
      [
        0.7296639905822224
      ],
      [
        0.862184728858717
      ],
      [
        0.843876486608424
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.7122548529277632
      ],
      [
        0.34767408245380094
      ],
      [
        0.017013081107529193
      ],
      [
        0.46120985234722733
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.30557377210246217
      ],
      [
        0.21884594146066183
      ],
      [
        0.20825208356072
      ],
      [
        0.5699187156427699
      ]
    ]
  }
]

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([[0.91894714],
       [0.72966399],
       [0.86218473],
       [0.84387649]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.71225485],
       [0.34767408],
       [0.01701308],
       [0.46120985]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.30557377],
       [0.21884594],
       [0.20825208],
       [0.56991872]]))]