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": [
    [
      0.7518855799812371,
      0.14624305379137237,
      0.5227480488120114
    ],
    [
      0.76731021458696,
      0.29074678440683366,
      0.187150524052905
    ],
    [
      0.2432162331242278,
      0.3810103639216561,
      0.2601062418481568
    ],
    [
      0.21700541754778768,
      0.15259706884422186,
      0.05744503757972086
    ],
    [
      0.5441443577750936,
      0.5807235949788219,
      0.013093073103979669
    ]
  ]
}

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": [
      [
        0.5168885403932835
      ],
      [
        0.4757337842724021
      ],
      [
        0.4399155615237992
      ],
      [
        0.7302655593505906
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.23005540688789583
      ],
      [
        0.19432031594688104
      ],
      [
        0.589946188688903
      ],
      [
        0.2769184885987399
      ]
    ]
  },
  {
    "version": 1,
    "M": 4,
    "basis_function": "B3",
    "closed": true,
    "control_points": [
      [
        0.5385217691646141
      ],
      [
        0.8103622788420788
      ],
      [
        0.4609927718961655
      ],
      [
        0.6475933135192288
      ]
    ]
  }
]

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([[0.51688854],
       [0.47573378],
       [0.43991556],
       [0.73026556]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.23005541],
       [0.19432032],
       [0.58994619],
       [0.27691849]])), splinebox.spline_curves.Spline(M=4, basis_function=splinebox.basis_functions.B3(), closed=True, control_points=np.array([[0.53852177],
       [0.81036228],
       [0.46099277],
       [0.64759331]]))]