Question

I want to have labels with small size on a piechart in python to improve visibility
here is the code

import matplotlib.pyplot as plt

frac=[1.40 , 10.86 , 19.31 , 4.02 , 1.43 , 2.66 , 4.70 , 0.70 , 0.13 , 1.48, 32.96 , 1.11 , 13.30 , 5.86]
labels=['HO0900344', 'HO0900331', 'HO0900332', 'HO0900354', 
'HO0900358', 'HO0900374', 'HO0900372', 'HO0900373', 
'HO0900371', 'HO0900370', 'HO0900369', 'HO0900356', 
'HO0900353', 'HO0900343']

fig = plt.figure(1, figsize=(6,6))
ax = fig.add_subplot(111)
ax.axis('equal')
colors=('b', 'g', 'r', 'c', 'm', 'y', 'burlywood', 'w')
ax.pie(frac,colors=colors ,labels=labels, autopct='%1.1f%%')
plt.show()

Answer 1

There are a couple of ways you can change the font size of the labels.

You can dynamically changet the rc settings. Add the following at the top of your script:

import matplotlib as mpl
mpl.rcParams['font.size'] = 9.0

Or you can modify the labels after they have been created. When you call ax.pie it returns a tuple of (patches, texts, autotexts). As an example, modify your final few lines of code as follows:

patches, texts, autotexts = ax.pie(frac, colors=colors, labels=labels, autopct='%1.1f%%')
texts[0].set_fontsize(4)
plt.show()