Volume non-orthogonal slicing animation

Perform non-orthogonal slicing of image volumes.

For an example with UI sliders see the “Volume modes” example.

/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pygfx/objects/_ruler.py:400: RuntimeWarning: divide by zero encountered in divide
  screen_full = (ndc_full[:, :2] / ndc_full[:, 3:4]) * half_canvas_size
/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pygfx/objects/_ruler.py:400: RuntimeWarning: invalid value encountered in divide
  screen_full = (ndc_full[:, :2] / ndc_full[:, 3:4]) * half_canvas_size
/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pygfx/objects/_ruler.py:412: RuntimeWarning: invalid value encountered in divide
  screen_sel = (ndc_sel[:, :2] / ndc_sel[:, 3:4]) * half_canvas_size

# test_example = false

import numpy as np
import fastplotlib as fpl
import imageio.v3 as iio


voldata = iio.imread("imageio:stent.npz").astype(np.float32)

figure = fpl.Figure(
    cameras="3d",
    controller_types="orbit",
    size=(700, 560)
)

vol = figure[0, 0].add_image_volume(voldata, mode="slice")

# a plane is defined by ax + by + cz + d = 0
# the plane property sets (a, b, c, d)
vol.plane = (0, 0.5, 0.5, -20)

# just a pre-saved camera state to view the plot area
state = {
    "position": np.array([-110.0,  160.0,  240.0]),
    "rotation": np.array([-0.25, -0.5, -0.15,  0.85]),
    "scale": np.array([1., 1., 1.]),
    "reference_up": np.array([0., 1., 0.]),
    "fov": 50.0,
    "width": 128.0,
    "height": 128.0,
    "depth": 315,
    "zoom": 0.75,
    "maintain_aspect": True,
    "depth_range": None
}

def update():
    # increase d by 1
    vol.plane = (0, 0.5, 0.5, vol.plane[-1] - 1)
    if vol.plane[-1] < -200:
        vol.plane = (0, 0.5, 0.5, -20)

figure[0, 0].add_animations(update)

figure.show()

figure[0, 0].camera.set_state(state)


# NOTE: fpl.loop.run() should not be used for interactive sessions
# See the "JupyterLab and IPython" section in the user guide
if __name__ == "__main__":
    print(__doc__)
    fpl.loop.run()