Bug report

Bug summary

Clicking on the figure options button (only available in the Qt backend) when showing an image does not work anymore. The dialog does not open and the script throws a TypeError.

Code for reproduction

from matplotlib import use
use('Qt5Agg')

import numpy as np
import matplotlib.pyplot as plt

data = np.ones((10,10))

plt.figure()
plt.imshow(data)
plt.show()

Click on figure options button (the second one from the right).

Actual outcome

Figure options dialog is not shown, instead a TypeError is thrown:

Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/matplotlib/backends/backend_qt5.py", line 681, in edit_parameters
    figureoptions.figure_edit(axes, self)
  File "/usr/lib/python2.7/site-packages/matplotlib/backends/qt_editor/figureoptions.py", line 168, in figure_edit
    + [(name, name) for name in sorted(image.iterpnames)])]
TypeError: 'instancemethod' object is not iterable

Expected outcome

Figure options dialog is opened and the script does not throw the TypeError. Used to work in matplot 2.0.2.

Matplotlib version

Bug introduced in matplotlib 2.1.0, specifcally this commit:

6ee70cb

changes 'iterpnames' from a variable (which is iterable) into a function (which must be called). The callside (figureoptions.py) was not modified accordingly. I guess adding '()' after iterpnames in figureoptions.py line 168 fixes the problem (untested).