How do I set the figure title and axes labels font size in Matplotlib

Question

I am creating a figure in Matplotlib like this:

from matplotlib import pyplot as plt

fig = plt.figure()
plt.plot(data)
fig.suptitle('test title')
plt.xlabel('xlabel')
plt.ylabel('ylabel')
fig.savefig('test.jpg')

I want to specify font sizes for the figure title and the axis labels. I need all three to be different font sizes, so setting a global font size (mpl.rcParams['font.size']=x) is not what I want. How do I set font sizes for the figure title and the axis labels individually?

Answer 1

Functions dealing with text like label, title, etc. accept parameters same as matplotlib.text.Text. For the font size you can use size/fontsize:

from matplotlib import pyplot as plt    

fig = plt.figure()
plt.plot(data)
fig.suptitle('test title', fontsize=20)
plt.xlabel('xlabel', fontsize=18)
plt.ylabel('ylabel', fontsize=16)
fig.savefig('test.jpg')

For globally setting title and label sizes, mpl.rcParams contains axes.titlesize and axes.labelsize. (From the page):

axes.titlesize      : large   # fontsize of the axes title
axes.labelsize      : medium  # fontsize of the x any y labels

(As far as I can see, there is no way to set x and y label sizes separately.)

And I see that axes.titlesize does not affect suptitle. I guess, you need to set that manually.

Answer 2

Setting the font size of the figure title and axis labels in a Matplotlib graph specifies the size of the text in the graph's title and axis labels.

When defining the labels of the graph using matplotlib.pyplot.xlabel(xlabel), matplotlib.pyplot.ylabel(ylabel), and matplotlib.pyplot.suptitle(t), add the parameter fontsize=int to each function call with int as the desired font size.

plt.figure()

x = [1,2]

y = [1,2]

plt.plot(x,y)

plt.xlabel('x-axis', fontsize=20)

specify font sizes

plt.ylabel('y-axis', fontsize=20)

plt.suptitle('Graph Title', fontsize=30)