Matplotlib Figuresize被rcParams忽略

Question

I have previously used the following to ensure my figure-size in my plots is a consistent size:

import matplotlib as mpl
rc_fonts = {'figure.figsize': (15, 9.3)}
mpl.rcParams.update(rc_fonts)
import matplotlib.pylab as plt

However, I am now finding that for my usual default values (15, 9.3) this is being ignored. The following demonstrates this:

import matplotlib as mpl
rc_fonts = {'figure.figsize': (15, 9.3)}
mpl.rcParams.update(rc_fonts)
import matplotlib.pylab as plt
# I draw some boring plot. 
plt.clf()
plt.plot(*[range(10)]*2)
print plt.gcf().get_size_inches()
print mpl.rcParams['figure.figsize']
plt.gcf().set_size_inches(15, 9.3, forward=True)
print plt.gcf().get_size_inches()

The initial plot size is [10.35, 9.3] and after it is [15, 9.3] as desired. If however I make the default very much large or smaller, eg (32, 19.3) then the figure window is correctly sized. I would like to keep my desired route of changing rcParams to set the default, rather than trying to set it twice by making an interim dummy plot. Is this a bug, or am I going about this the wrong way?

Details:

• Python 2.7.12 (inside a virtual environment, a must).
• Backend TkAgg (I want this kept as it is).
• Matplotlib version 2.1.0. (This bug/feature persists in version 2.1.2 also).

PS - I prefer avoiding having to make matplotlib fig and ax objects and instead use the plt interface directly. If possible I would like to keep it this way with any solutions.

Possible known issue:

I have found the following issue 2716 on github which I think is causing this, but there don't appear any fixes suitable for the rcParam settings route. So any help or suggestions are still welcome.

Current output:

Following the comments below is some example output (done using Python 3 to allow me to install the latest version of matplotlib):

Python 3.5.2 (default, Nov 23 2017, 16:37:01) 
[GCC 5.4.0 20160609] on linux
>>> 
... import matplotlib as mpl
... print(mpl.__version__)
... rc_fonts = {'figure.figsize': (15, 9.3)}
... mpl.rcParams.update(rc_fonts)
... import matplotlib.pylab as plt
... plt.plot(*[range(10)]*2)
... 
Backend Qt4Agg is interactive backend. Turning interactive mode on.
2.2.0rc1+124.gf1f83f6
>>> 
... print(plt.gcf().get_size_inches())
... print(mpl.rcParams['figure.figsize'])
... plt.gcf().set_size_inches(15, 9.3, forward=True)
... print(plt.gcf().get_size_inches())
... 
[ 10.35   9.3 ]
[15.0, 9.3]
[ 15.    9.3]

DEMONSTRATION

Root of the problem

As explained in the accepted answer, the issue is that I am using more than one display, and Matplotlib cannot produce a window that is larger than the primary display. Unfortunately changing what Ubuntu considers to be the primary display is currently an unresolved bug. Hence the problem does not lie with Matplotlib, but with Ubuntu. I was able to resolve this issue by setting the display to the top left monitor in my setup.

Answer 1

The problem occurs because there are several screens in use and the one the figure is shown in is not the primary one.

There is currently no way to automatically show the figure larger than a maximized window on the primary screen would allow for. If the figure is larger than that, it is still shrunk to fit the plotting window.

After the window is initiated, one may indeed resize the figure to any other size, as is being done in the question using

plt.gcf().set_size_inches(15, 9.3, forward=True)