Updating the x-axis values using matplotlib animation

Question

I am trying to use matplotlib.ArtistAnimation to animate two subplots. I want the x-axis to increase in value as the animation progresses, such that the total l

Answer 1

If you are using blitting, you can call pyplot.draw() to redraw the entire figure, each time you change y/x axis.

This updates whole figure, so is relatively slow, but it's acceptable if you don't call it many items.

Answer 2

This moves your axis, but is very slow.

import matplotlib.pylab as plt
import matplotlib.animation as anim
import numpy as np


image = np.random.rand(100,10,10)
repeat_length = (np.shape(image)[0]+1)/4

fig = plt.figure()
ax1 = ax1=fig.add_subplot(1,2,1)
im = ax1.imshow(image[0,:,:])

ax2 = plt.subplot(122)
ax2.set_xlim([0,repeat_length])
ax2.set_ylim([np.amin(image[:,5,5]),np.amax(image[:,5,5])])
im2, = ax2.plot(image[0:0,5,5],color=(0,0,1))

canvas = ax2.figure.canvas

def init():
    im = ax1.imshow(image[0,:,:])
    im2.set_data([], [])
    return im,im2,

def animate(time):
    time = time%len(image)
    im = ax1.imshow(image[time,:,:])
    im2, = ax2.plot(image[0:time,5,5],color=(0,0,1))
    if time>repeat_length:
        print time
        im2.axes.set_xlim(time-repeat_length,time)
        plt.draw()
    return im,im2,

ax2.get_yaxis().set_animated(True)

# call the animator.  blit=True means only re-draw the parts that have changed.
animate = anim.FuncAnimation(fig, animate, init_func=init,
                               interval=0, blit=True, repeat=True)

plt.show()

Answer 3

If you don't need blitting

import matplotlib.pylab as plt
import matplotlib.animation as animation
import numpy as np

#create image with format (time,x,y)
image = np.random.rand(100,10,10)

#setup figure
fig = plt.figure()
ax1 = fig.add_subplot(1,2,1)
ax2 = fig.add_subplot(1,2,2)
#set up viewing window (in this case the 25 most recent values)
repeat_length = (np.shape(image)[0]+1)/4
ax2.set_xlim([0,repeat_length])
#ax2.autoscale_view()
ax2.set_ylim([np.amin(image[:,5,5]),np.amax(image[:,5,5])])

#set up list of images for animation


im = ax1.imshow(image[0,:,:])
im2, = ax2.plot([], [], color=(0,0,1))

def func(n):
    im.set_data(image[n,:,:])

    im2.set_xdata(np.arange(n))
    im2.set_ydata(image[0:n, 5, 5])
    if n>repeat_length:
        lim = ax2.set_xlim(n-repeat_length, n)
    else:
        # makes it look ok when the animation loops
        lim = ax2.set_xlim(0, repeat_length)
    return im, im2

ani = animation.FuncAnimation(fig, func, frames=image.shape[0], interval=30, blit=False)

plt.show()

will work.

If you need to run faster, you will need to play games with the bounding box used for blitting so that the axes labels are updated.