How do I set the figure title and axes labels font size in Matplotlib?
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?
Solution 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.
Solution 2:
You can also do this globally via a rcParams dictionary:
import matplotlib.pylab as pylab
params = {'legend.fontsize': 'x-large',
'figure.figsize': (15, 5),
'axes.labelsize': 'x-large',
'axes.titlesize':'x-large',
'xtick.labelsize':'x-large',
'ytick.labelsize':'x-large'}
pylab.rcParams.update(params)
Solution 3:
If you're more used to using ax
objects to do your plotting, you might find the ax.xaxis.label.set_size()
easier to remember, or at least easier to find using tab in an ipython terminal. It seems to need a redraw operation after to see the effect. For example:
import matplotlib.pyplot as plt
# set up a plot with dummy data
fig, ax = plt.subplots()
x = [0, 1, 2]
y = [0, 3, 9]
ax.plot(x,y)
# title and labels, setting initial sizes
fig.suptitle('test title', fontsize=12)
ax.set_xlabel('xlabel', fontsize=10)
ax.set_ylabel('ylabel', fontsize='medium') # relative to plt.rcParams['font.size']
# setting label sizes after creation
ax.xaxis.label.set_size(20)
plt.draw()
I don't know of a similar way to set the suptitle size after it's created.
Solution 4:
To only modify the title's font (and not the font of the axis) I used this:
import matplotlib.pyplot as plt
fig = plt.Figure()
ax = fig.add_subplot(111)
ax.set_title('My Title', fontdict={'fontsize': 8, 'fontweight': 'medium'})
The fontdict accepts all kwargs from matplotlib.text.Text.
Solution 5:
Per the official guide, use of
pylab
is no longer recommended.matplotlib.pyplot
should be used directly instead.
Globally setting font sizes via rcParams
should be done with
import matplotlib.pyplot as plt
plt.rcParams['axes.labelsize'] = 16
plt.rcParams['axes.titlesize'] = 16
# or
params = {'axes.labelsize': 16,
'axes.titlesize': 16}
plt.rcParams.update(params)
# or
import matplotlib as mpl
mpl.rc('axes', labelsize=16, titlesize=16)
# or
axes = {'labelsize': 16,
'titlesize': 16}
mpl.rc('axes', **axes)
The defaults can be restored using
plt.rcParams.update(plt.rcParamsDefault)
You can also do this by creating a style sheet in the stylelib
directory under the matplotlib configuration directory (you can get your configuration directory from matplotlib.get_configdir()
). The style sheet format is
axes.labelsize: 16
axes.titlesize: 16
If you have a style sheet at /path/to/mpl_configdir/stylelib/mystyle.mplstyle
then you can use it via
plt.style.use('mystyle')
# or, for a single section
with plt.style.context('mystyle'):
# ...
You can also create (or modify) a matplotlibrc file which shares the format
axes.labelsize = 16
axes.titlesize = 16
Depending on which matplotlibrc file you modify these changes will be used for only the current working directory, for all working directories which do not have a matplotlibrc file, or for all working directories which do not have a matplotlibrc file and where no other matplotlibrc file has been specified. See this section of the customizing matplotlib page for more details.
A complete list of the rcParams
keys can be retrieved via plt.rcParams.keys()
, but for adjusting font sizes you have (italics quoted from here)
-
axes.labelsize
- Fontsize of the x and y labels -
axes.titlesize
- Fontsize of the axes title -
figure.titlesize
- Size of the figure title (Figure.suptitle()
) -
xtick.labelsize
- Fontsize of the tick labels -
ytick.labelsize
- Fontsize of the tick labels -
legend.fontsize
- Fontsize for legends (plt.legend()
,fig.legend()
) -
legend.title_fontsize
- Fontsize for legend titles,None
sets to the same as the default axes. See this answer for usage example.
all of which accept string sizes {'xx-small', 'x-small', 'smaller', 'small', 'medium', 'large', 'larger', 'x-large', 'xxlarge'}
or a float
in pt
. The string sizes are defined relative to the default font size which is specified by
-
font.size
- the default font size for text, given in pts. 10 pt is the standard value
Additionally, the weight can be specified (though only for the default it appears) by
-
font.weight
- The default weight of the font used bytext.Text
. Accepts{100, 200, 300, 400, 500, 600, 700, 800, 900}
or'normal'
(400),'bold'
(700),'lighter'
, and'bolder'
(relative with respect to current weight).