Bug report

Bug summary

When using%matplotlib notebook in Jupyter Notebooks on a HiDPI screen (tested on multiple MacBooks of different generations), the plot stays half-sized until the cell is finished with all its computations.

Code for reproduction

%matplotlibnotebookimportmatplotlib.pyplotaspltimportnumpyasnpimporttimedefdraw(ax):"""Scatter some new data into an axis."""ax.cla()ax.scatter(*np.random.rand(2,1000))ax.get_figure().canvas.draw()_,ax=plt.subplots(1,1)for_inrange(10):# Draw some new datadraw(ax)# Do some intermediate computationstime.sleep(.1)# Plot wont upscale till this sleep is overtime.sleep(10)

Actual outcome

Plots stay small until lastsleep finishes.

Expected outcome

Plots should rescale to screen's DPI right after initial drawing.

Matplotlib version

• Operating system: Ubuntu 16.04 / macOS 10.13
• Matplotlib version:2.1.2
• Matplotlib backend:nbAgg
• Python version:3.6.4
• Jupyter version:4.4.0

Other Information

#5383 is probably relevant for when attempting to fix this problem.