Matplotlib tight_layout() doesn't take into account figure suptitle

问题:

If I add a subtitle to my matplotlib figure it gets overlaid by the subplot's titles. Does anybody know how to easily take care of that? I tried the tight_layout() function, but it only makes things worse.

Example:

import numpy as np import matplotlib.pyplot as plt  f = np.random.random(100) g = np.random.random(100) fig = plt.figure() fig.suptitle('Long Suptitle', fontsize=24) plt.subplot(121) plt.plot(f) plt.title('Very Long Title 1', fontsize=20) plt.subplot(122) plt.plot(g) plt.title('Very Long Title 2', fontsize=20) plt.tight_layout() plt.show() 

回答1:

You can adjust the subplot geometry in the very tight_layout call as follows:

fig.tight_layout(rect=[0, 0.03, 1, 0.95]) 

As it's stated in the documentation (https://matplotlib.org/users/tight_layout_guide.html):

tight_layout() only considers ticklabels, axis labels, and titles. Thus, other artists may be clipped and also may overlap.

P.S. Community recommended me to post my comment as an answer.

回答2:

You could manually adjust the spacing using plt.subplots_adjust(top=0.85):

import numpy as np import matplotlib.pyplot as plt  f = np.random.random(100) g = np.random.random(100) fig = plt.figure() fig.suptitle('Long Suptitle', fontsize=24) plt.subplot(121) plt.plot(f) plt.title('Very Long Title 1', fontsize=20) plt.subplot(122) plt.plot(g) plt.title('Very Long Title 2', fontsize=20) plt.subplots_adjust(top=0.85) plt.show() 

回答3:

One thing you could change in your code very easily is the fontsize you are using for the titles. However, I am going to assume that you don't just want to do that!

Some alternatives to using fig.subplots_adjust(top=0.85):

Usually tight_layout() does a pretty good job at positioning everything in good locations so that they don't overlap. The reason tight_layout() doesn't help in this case is because tight_layout() does not take fig.suptitle() into account. There is an open issue about this on GitHub: https://github.com/matplotlib/matplotlib/issues/829 [closed in 2014 due to requiring a full geometry manager - shifted to https://github.com/matplotlib/matplotlib/issues/1109 ].

If you read the thread, there is a solution to your problem involving GridSpec. The key is to leave some space at the top of the figure when calling tight_layout, using the rect kwarg. For your problem, the code becomes:

Using GridSpec

import numpy as np import matplotlib.pyplot as plt import matplotlib.gridspec as gridspec  f = np.random.random(100) g = np.random.random(100)  fig = plt.figure(1) gs1 = gridspec.GridSpec(1, 2) ax_list = [fig.add_subplot(ss) for ss in gs1]  ax_list[0].plot(f) ax_list[0].set_title('Very Long Title 1', fontsize=20)  ax_list[1].plot(g) ax_list[1].set_title('Very Long Title 2', fontsize=20)  fig.suptitle('Long Suptitle', fontsize=24)      gs1.tight_layout(fig, rect=[0, 0.03, 1, 0.95])    plt.show() 

The result:

Maybe GridSpec is a bit overkill for you, or your real problem will involve many more subplots on a much larger canvas, or other complications. A simple hack is to just use annotate() and lock the coordinates to the 'figure fraction' to imitate a suptitle. You may need to make some finer adjustments once you take a look at the output, though. Note that this second solution does not use tight_layout().

Simpler solution (though may need to be fine-tuned)

fig = plt.figure(2)  ax1 = plt.subplot(121) ax1.plot(f) ax1.set_title('Very Long Title 1', fontsize=20)  ax2 = plt.subplot(122) ax2.plot(g) ax2.set_title('Very Long Title 2', fontsize=20)  # fig.suptitle('Long Suptitle', fontsize=24) # Instead, do a hack by annotating the first axes with the desired  # string and set the positioning to 'figure fraction'. fig.get_axes()[0].annotate('Long Suptitle', (0.5, 0.95),                              xycoords='figure fraction', ha='center',                              fontsize=24                             ) plt.show() 

The result:

[Using Python 2.7.3 (64-bit) and matplotlib 1.2.0]

回答4:

An alternative and simple to use solution is to adjust the coordinates of the suptitle text in the figure using the y argument in the call of suptitle (see the docs):

import numpy as np import matplotlib.pyplot as plt  f = np.random.random(100) g = np.random.random(100) fig = plt.figure() fig.suptitle('Long Suptitle', y=1.05, fontsize=24) plt.subplot(121) plt.plot(f) plt.title('Very Long Title 1', fontsize=20) plt.subplot(122) plt.plot(g) plt.title('Very Long Title 2', fontsize=20) plt.show() 

回答5:

I have struggled with the matplotlib trimming methods, so I've now just made a function to do this via a bash call to ImageMagick's mogrify command, which works well and gets all extra white space off the figure's edge. This requires that you are using UNIX/Linux, are using the bash shell, and have ImageMagick installed.

Just throw a call to this after your savefig() call.

def autocrop_img(filename):     '''Call ImageMagick mogrify from bash to autocrop image'''     import subprocess     import os      cwd, img_name = os.path.split(filename)      bashcmd = 'mogrify -trim %s' % img_name     process = subprocess.Popen(bashcmd.split(), stdout=subprocess.PIPE, cwd=cwd) 

文章来源: Matplotlib tight_layout() doesn't take into account figure suptitle