Closed
Description
Bug report
While reviewing #10187 it was noted the cv.flush_events does not work the same with the osx backend as the other GUI backends.
I suspect that if someone knows how to work with the OSX GUI code this will be straight forward to implement.
Bug summary
The issue is likely the flush_events function in the objective-c code does not appear to process any of the pending UI events
Lines 391 to 402 in 77f23da
The
Code for reproduction
Run the exampls in #10187
import matplotlib.pyplot as plt
import numpy as np
x = np.linspace(0, 2 * np.pi, 100)
fig, ax = plt.subplots()
# animated=True tells matplotlib to only draw the artist when we
# explicitly request it
(ln,) = ax.plot(x, np.sin(x), animated=True)
# make sure the window is raised, but the script keeps going
plt.show(block=False)
# stop to admire our empty window axes and ensure it is rendered at
# least once.
#
# We need to fully draw the figure at its final size on the screen
# before we continue on so that :
# a) we have the correctly sized and drawn background to grab
# b) we have a cached renderer so that ``ax.draw_artist`` works
# so we spin the event loop to let the backend process any pending operations
plt.pause(0.1)
# get copy of entire figure (everything inside fig.bbox) sans animated artist
bg = fig.canvas.copy_from_bbox(fig.bbox)
# draw the animated artist, this uses a cached renderer
ax.draw_artist(ln)
# show the result to the screen, this pushes the updated RGBA buffer from the
# renderer to the GUI framework so you can see it
fig.canvas.blit(fig.bbox)
for j in range(100):
# reset the background back in the canvas state, screen unchanged
fig.canvas.restore_region(bg)
# update the artist, neither the canvas state nor the screen have changed
ln.set_ydata(np.sin(x + (j / 100) * np.pi))
# re-render the artist, updating the canvas state, but not the screen
ax.draw_artist(ln)
# copy the image to the GUI state, but screen might not changed yet
fig.canvas.blit(fig.bbox)
# flush any pending GUI events, re-painting the screen if needed
fig.canvas.flush_events()
# you can put a pause in if you want to slow things down
# plt.pause(.1)Actual outcome
The window does not update during the loop
Expected outcome
It behaves as when plt.pause(.1) is un-commented
Matplotlib version
- Operating system: OSX
- Matplotlib version: 3.2+
- Matplotlib backend (
print(matplotlib.get_backend())): OSX - Python version: ?