Edit: Note that this issue is also still present with Qt5Agg and matplotlib 3.0.1
Showing a figure with Qt4Agg backend changes the figure size. This is observed with Windows 8.1, python 2.7, matplotlib 2.1.
import matplotlib
matplotlib.use("Qt4Agg")
import matplotlib.pyplot as plt
fig, ax = plt.subplots()
ax.plot([1,2,4])
def update(evt):
print(fig.get_size_inches())
cid = fig.canvas.mpl_connect("key_press_event", update)
print(fig.get_size_inches())
plt.show()
The original figure is [ 6.4 4.8]. After the figure is drawn (and in this case you press a key), it is only [ 6.4 4.78].
One could argue that this is only a small amount, but saving the figure from within the event loop now gives a different figure size of the saved figure. To make this more obvious, consider the following code which saves a new image after each press of space.
import matplotlib
matplotlib.use("Qt4Agg")
import matplotlib.pyplot as plt
import numpy as np
class NextPlotter(object):
def __init__(self, fig, func, n):
self.__dict__.update(locals())
self.i = 0
self.cid = self.fig.canvas.mpl_connect("key_press_event", self.adv)
def adv(self, evt):
if evt.key == " " and self.i < self.n:
self.func(self.i)
self.i+=1
elif self.i >= self.n:
plt.close("all")
# Create data
pos = range(8)
scatterdata = np.random.normal(0, 5, size=(50,len(pos)))
#Create plot
fig, ax = plt.subplots()
ax.axis([-10,10,-10,10])
scatter = ax.scatter([], [], c="crimson", s=60)
# define updating function
def update(i):
print("++ update " + str(i))
scatter.set_offsets(np.c_[pos,scatterdata[i,:]])
fig.canvas.draw()
print(fig.get_size_inches())
plt.savefig("plot_{i}.png".format(i=i))
print(fig.get_size_inches())
# instantiate NextPlotter; press <space> to advance to the next image
c = NextPlotter(fig, update, len(scatterdata))
plt.show()
resulting in
Is this a problem of PyQt4? Can anyone reproduce this outside of Windows 8?
Edit: Note that this issue is also still present with Qt5Agg and matplotlib 3.0.1
Showing a figure with Qt4Agg backend changes the figure size. This is observed with Windows 8.1, python 2.7, matplotlib 2.1.
The original figure is
[ 6.4 4.8]. After the figure is drawn (and in this case you press a key), it is only[ 6.4 4.78].One could argue that this is only a small amount, but saving the figure from within the event loop now gives a different figure size of the saved figure. To make this more obvious, consider the following code which saves a new image after each press of space.
resulting in
Is this a problem of PyQt4? Can anyone reproduce this outside of Windows 8?