matplotlib - 在 Mayavi 体积可视化中使用感知均匀的色彩图

Question

据我所知 Mayavi 没有提供任何感知上统一的色彩图。我天真地试图通过它one of Matplotlib's colormaps但失败了:

from mayavi import mlab
import multiprocessing
import matplotlib.pyplot as plt

plasma = plt.get_cmap('plasma')

...
mlab.pipeline.volume(..., colormap=plasma)

TraitError: Cannot set the undefined 'colormap' attribute of a 'VolumeFactory' object.

---

编辑:我发现a guide将 Matplotlib 颜色图转换为 Mayavi 颜色图。但是，不幸的是，它不起作用，因为我尝试使用使用感知均匀颜色图的体积。

from matplotlib.cm import get_cmap
import numpy as np
from mayavi import mlab

values = np.linspace(0., 1., 256)
lut_dict = {}
lut_dict['plasma'] = get_cmap('plasma')(values.copy())

x, y, z = np.ogrid[-10:10:20j, -10:10:20j, -10:10:20j]
s = np.sin(x*y*z)/(x*y*z)

mlab.pipeline.volume(mlab.pipeline.scalar_field(s), vmin=0, vmax=0.8, colormap=lut_dict['plasma'])  # still getting the same error
mlab.axes()
mlab.show()

...

Answer 1

如果将其设置为体积的 ColorTransferFunction，而不是将其设置为 colormap 参数，则它会按预期工作。

import numpy as np
from mayavi import mlab
from tvtk.util import ctf
from matplotlib.pyplot import cm

values = np.linspace(0., 1., 256)
x, y, z = np.ogrid[-10:10:20j, -10:10:20j, -10:10:20j]
s = np.sin(x*y*z)/(x*y*z)

volume = mlab.pipeline.volume(mlab.pipeline.scalar_field(s), vmin=0, vmax=0.8)
# save the existing colormap
c = ctf.save_ctfs(volume._volume_property)
# change it with the colors of the new colormap
# in this case 'plasma'
c['rgb']=cm.get_cmap('plasma')(values.copy())
# load the color transfer function to the volume
ctf.load_ctfs(c, volume._volume_property)
# signal for update
volume.update_ctf = True

mlab.show()