How to use matplotlib tight layout with Figure?
Just call fig.tight_layout() as you normally would. (pyplot is just a convenience wrapper. In most cases, you only use it to quickly generate figure and axes objects and then call their methods directly.)
There shouldn't be a difference between the QtAgg backend and the default backend (or if there is, it's a bug).
E.g.
import matplotlib.pyplot as plt#-- In your case, you'd do something more like:# from matplotlib.figure import Figure# fig = Figure()#-- ...but we want to use it interactive for a quick example, so #-- we'll do it this wayfig, axes = plt.subplots(nrows=4, ncols=4)for i, ax in enumerate(axes.flat, start=1): ax.set_title('Test Axes {}'.format(i)) ax.set_xlabel('X axis') ax.set_ylabel('Y axis')plt.show()Before Tight Layout
After Tight Layout
import matplotlib.pyplot as pltfig, axes = plt.subplots(nrows=4, ncols=4)for i, ax in enumerate(axes.flat, start=1): ax.set_title('Test Axes {}'.format(i)) ax.set_xlabel('X axis') ax.set_ylabel('Y axis')fig.tight_layout()plt.show()