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": [
    [
      0.49053197557926065,
      0.10765603351018949,
      0.9647843304731141
    ],
    [
      0.21645602683801257,
      0.06716763273942628,
      0.22421048641878727
    ],
    [
      0.6436510045048892,
      0.3518983429697824,
      0.3722745635088399
    ],
    [
      0.025054069498858356,
      0.09957575005626185,
      0.9069446686347781
    ],
    [
      0.7394955121252277,
      0.5675679479051441,
      0.24983936222157566
    ]
  ]
}

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": [
      [
        0.7381678974519859
      ],
      [
        0.5394629555325402
      ],
      [
        0.27135898430030236
      ],
      [
        0.8485531627816226
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.7842041215336754
      ],
      [
        0.29202708138612876
      ],
      [
        0.029241591373653564
      ],
      [
        0.786772350266552
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.7198331117456962
      ],
      [
        0.26891928917412167
      ],
      [
        0.2710133187982756
      ],
      [
        0.5925872767436073
      ]
    ]
  }
]

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([[0.7381679 ],
       [0.53946296],
       [0.27135898],
       [0.84855316]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.78420412],
       [0.29202708],
       [0.02924159],
       [0.78677235]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.71983311],
       [0.26891929],
       [0.27101332],
       [0.59258728]]))]