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": [
    [
      0.5016554724171337,
      0.4416238786606088,
      0.47326702721774216
    ],
    [
      0.6524722460097683,
      0.6053770432208045,
      0.695026971010336
    ],
    [
      0.7070316286033038,
      0.5142548801152815,
      0.6724847941328402
    ],
    [
      0.37819506061997454,
      0.5616607913638806,
      0.49958695237608364
    ],
    [
      0.8575693930955125,
      0.11137196391037596,
      0.2556912503928378
    ]
  ]
}

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": [
      [
        0.031686973636141036
      ],
      [
        0.7250896209096424
      ],
      [
        0.7219699327486673
      ],
      [
        0.7516050255478786
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.5901515014187777
      ],
      [
        0.3668762902814704
      ],
      [
        0.36227291731273736
      ],
      [
        0.37737078500584276
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.7830228207359472
      ],
      [
        0.7605990520865326
      ],
      [
        0.8375530694167694
      ],
      [
        0.75948785047537
      ]
    ]
  }
]

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([[0.03168697],
       [0.72508962],
       [0.72196993],
       [0.75160503]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.5901515 ],
       [0.36687629],
       [0.36227292],
       [0.37737079]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.78302282],
       [0.76059905],
       [0.83755307],
       [0.75948785]]))]