mplot3d animation with transparent background

Question

I want to generate some gifs with transparent background using matplotlib. I tried different options but I can\'t get my files with transparent background. With the current

Answer 1

I think it's really a bug. However, if you rather care about the result than the way to get there, the following would do the job. Instead of calling animation, you can save each image separately and then call imageMagick to convert them to an animated gif. See the code below and mind the arguments to convert.exe.

from __future__ import division
from numpy import pi, sin, cos, mgrid
from scipy.special import jn, jn_zeros
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt

from matplotlib import rcParams
import subprocess


# In Windows the next line should provide the full path to convert.exe
# since convert is a Windows command
path_to_convert =  "C:\Program Files\ImageMagick-6.9.3\convert.exe"
#rcParams['animation.convert_path'] = path_to_convert
rcParams['savefig.transparent'] = True
rcParams['savefig.dpi'] = 130
rcParams['savefig.pad_inches'] = 0
plot_args = {'rstride': 1, 'cstride': 1, 'cmap':"RdYlBu",
             'linewidth': 0.5, 'antialiased': True, 'color': '#1e1e1e',
             'shade': True, 'alpha': 1.0, 'vmin': -1, 'vmax':1}


def data_gen(num):
    ax.cla()
    ax.clear()
    m, n = 1, 2
    lam = jn_zeros(m, n)[-1]
    dt = 2*pi/(30*lam)
    z = cos(m*t)*jn(m, lam*r)*sin(lam*num*dt)
    surf = ax.plot_surface(x, y, z, **plot_args)
    ax.view_init(elev=30, azim=45)
    ax.set_xlim(-0.6, 0.6)
    ax.set_ylim(-0.6, 0.6)
    ax.set_zlim(-1, 1)
    ax.axis("off")
    fig.patch.set_visible(False)
    ax.patch.set_visible(False)
    ax.set_axis_off()
    ax._axis3don = False
    return surf


r, t = mgrid[0:1:20j, 0:2*pi:40j]
x, y = r*cos(t), r*sin(t)
fig = plt.figure(facecolor=None, frameon=False)
ax = fig.add_subplot(111, projection='3d')
for i in range(30):
    data_gen(i)
    plt.savefig("drum_{n:02d}.png".format(n=i), transparent=True,  frameon=False)
    print i, 

args = [path_to_convert, "-delay", "10", "-loop" , "0", "-dispose", "Background", "drum_*.png", "output.gif"]
subprocess.call(args, shell=True)
subprocess.call(["del", "/Q", "drum_*.png"], shell=True)
print "\ndone"

Mind that the calls to imageMagick and the delete command might be system dependend. This script has been tested with imageMagick 7.0.3 (Q16) under Windows 8.