NumPy logo in rotating voxels

numpyrotate.py

'''
matplotlib must be developer release for voxel support
  install instructions:
https://matplotlib.org/devdocs/users/installing.html
'''

import matplotlib.pyplot as plt
import numpy as np
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.animation as manimation

FFMpegWriter = manimation.writers['ffmpeg']
metadata = dict(title='Movie Test', artist='Matplotlib',
                comment='Movie support!')
writer = FFMpegWriter(fps=25, metadata=metadata)

def explode(data):
    size = np.array(data.shape)*2
    data_e = np.zeros(size - 1, dtype=data.dtype)
    data_e[::2, ::2, ::2] = data
    return data_e

# build up the numpy logo
n_voxels = np.zeros((5, 5, 5), dtype=bool)
#N
n_voxels[0, 0, :] = True
n_voxels[-1, 0, :] = True
n_voxels[1, 0, 3] = True
n_voxels[2, 0, 2] = True
n_voxels[3, 0, 1] = True
#U
n_voxels[0, :, 0] = True
n_voxels[-1, :, 0] = True
n_voxels[:, -1, 0] = True
#Y
n_voxels[0, 1, -1] = True
n_voxels[-1, 1, -1] = True
n_voxels[:, 2, -1] = True
n_voxels[2, 3, -1] = True
n_voxels[2, 4, -1] = True
#M
n_voxels[0, -1, :] = True
n_voxels[2, -1, :] = True
n_voxels[-1, -1, :] = True
#P (negative space)
n_voxels[-1, 2, 2] = True

facecolors = np.where(n_voxels, '#FFD65DC0', '#7A88CC90')
#these are rgba values, the last 2 hex digits are opacity, ff=opaque, 00=clear
edgecolors = np.where(n_voxels, '#BFAB6E', '#7D84A6')
filled = np.ones(n_voxels.shape)

# upscale the above voxel image, leaving gaps
filled_2 = explode(filled)
fcolors_2 = explode(facecolors)
ecolors_2 = explode(edgecolors)

# Shrink the gaps
x, y, z = np.indices(np.array(filled_2.shape) + 1).astype(float) // 2
x[0::2, :, :] += 0.05
y[:, 0::2, :] += 0.05
z[:, :, 0::2] += 0.05
x[1::2, :, :] += 0.95
y[:, 1::2, :] += 0.95
z[:, :, 1::2] += 0.95

fig = plt.figure()
ax = fig.gca(projection='3d')
ax.axis("off")
ax.voxels(x, y, z, filled_2, facecolors=fcolors_2, edgecolors=ecolors_2)

view_elev = [-90, -90, -90, -180, 90, -90]
view_azim = [0, -90, 180, 180, 90, 0]

with writer.saving(fig, "npLogoRotate.mp4", 100):
    for i in range(1,len(view_elev)):

        de = (view_elev[i] - view_elev[i-1])
        da = (view_azim[i] - view_azim[i-1])

        if abs(da) > 180 :
            if da < 0 :
                da = da + 360
            else :
                da = da - 360
        if abs(de) > 180 :
            if de < 0 :
                de = de + 360
            else :
                de = de - 360

        da = int(da / 90)
        de = int(de / 90)

        for j in range(90):
            ce = view_elev[i-1] + j*de
            ca = view_azim[i-1] + j*da
            ax.view_init(ca, ce)
            plt.draw()
            writer.grab_frame()

Output