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": [
    [
      0.0902350965979708,
      0.8587298792667244,
      0.26328837232186675
    ],
    [
      0.776651622431395,
      0.8526353972457055,
      0.8829989463739728
    ],
    [
      0.6094372101879096,
      0.9010921596429333,
      0.3227110944337114
    ],
    [
      0.14870037987343854,
      0.2720037891539161,
      0.1943816595072786
    ],
    [
      0.3383776571414806,
      0.2795369394522912,
      0.6561813549837233
    ]
  ]
}

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": [
      [
        0.8856146403186085
      ],
      [
        0.7474087112120849
      ],
      [
        0.22604111044819997
      ],
      [
        0.11227376157806124
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.6567724333626876
      ],
      [
        0.5062940867519186
      ],
      [
        0.2808374280718251
      ],
      [
        0.12432462310167369
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.7363118703189538
      ],
      [
        0.458812963056637
      ],
      [
        0.8302801018471271
      ],
      [
        0.18246584178939151
      ]
    ]
  }
]

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([[0.88561464],
       [0.74740871],
       [0.22604111],
       [0.11227376]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.65677243],
       [0.50629409],
       [0.28083743],
       [0.12432462]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.73631187],
       [0.45881296],
       [0.8302801 ],
       [0.18246584]]))]