I've got an animation with lines and now I want to label the points.
I tried plt.annotate()
and I tried plt.text()
but the labes don't move.
This is my example code:
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
def update_line(num, data, line):
newData = np.array([[1+num,2+num/2,3,4-num/4,5+num],[7,4,9+num/3,2,3]])
line.set_data(newData)
plt.annotate('A0', xy=(newData[0][0],newData[1][0]))
return line,
fig1 = plt.figure()
data = np.array([[1,2,3,4,5],[7,4,9,2,3]])
l, = plt.plot([], [], 'r-')
plt.xlim(0, 20)
plt.ylim(0, 20)
plt.annotate('A0', xy=(data[0][0], data[1][0]))
# plt.text( data[0][0], data[1][0], 'A0')
line_ani = animation.FuncAnimation(fig1, update_line, 25, fargs=(data, l),
interval=200, blit=True)
plt.show()
Can you help me please?
My next step is: I have vectors with origin in these Points. These vectors change their length and their direction in each animation step. How can I animate these?
Without animation this works:
soa =np.array( [ [data[0][0],data[1][0],F_A0[i][0][0],F_A0[i][1][0]],
[data[0][1],data[1][1],F_B0[i][0][0],F_B0[i][1][0]],
[data[0][2],data[1][2],F_D[i][0][0],F_D[i][1][0]] ])
X,Y,U,V = zip(*soa)
ax = plt.gca()
ax.quiver(X,Y,U,V,angles='xy',scale_units='xy',scale=1)
First thanks a lot for your fast and very helpful answer!
My Vector animation problem I have solved with this:
annotation = ax.annotate("C0", xy=(data[0][2], data[1][2]), xycoords='data',
xytext=(data[0][2]+1, data[1][2]+1), textcoords='data',
arrowprops=dict(arrowstyle="->"))
and in the 'update-function' I write:
annotation.xytext = (newData[0][2], newData[1][2])
annotation.xy = (data[0][2]+num, data[1][2]+num)
to change the start and end position of the vectors (arrows).
But what is, wehn I have 100 vectors or more? It is not practicable to write:
annotation1 = ...
annotation2 = ...
.
:
annotation100 = ...
I tried with a list:
...
annotation = [annotation1, annotation2, ... , annotation100]
...
def update(num):
...
return line, annotation
and got this error: AttributeError: 'list' object has no attribute 'axes'
What can I do? Have you any idea?
You have the return all objects that changed from your update function. So since your annotation changed it's position you should return it also:
You can read more about
matplotlib
animations in this tutorialYou should also specify the
init
function so that theFuncAnimation
knows which elements to remove from the plot when redrawing on the first update. So the full example would be: