加速 Matplotlib

Question

Currently I am working on a real-time plot but the visualization is really slow. I would like to know what things in general you can do to speed up things in Matplotlib:

• How does the backend affect the performance? Are there backends that are better for real time plotting than others?
• Can I lower the resolution to increase FPS?
• Why does the FPS of my plot increase if I reduce the window size? Why does FPS drop dramatically if I switch to full screen mode?

I also tried to turn off everything I don't need:

ax.set_xticklabels(())
ax.set_yticklabels(())
ax.set_xticks([])
ax.set_yticks([])
ax.axis('off')
ax.get_xaxis().set_visible(False)
ax.get_yaxis().set_visible(False)

However, the effect is negligible. Are there more things I can turn off?

I would also like to know if it is possible to turn off the buttons (home button, etc.., see below) of the window that opens when creating a graph. May turning off these buttons increase the speed?

I also found that doing the following

fig.canvas.draw_idle()
fig.canvas.start_event_loop(1e-9)

is much slower for updating the plot than

fig.canvas.draw_idle()
self.fig.canvas.update()
self.fig.canvas.flush_events()

Are there even better ways to update the objects in a plot?

Answer 1

How does the backend affect the performance? Are there backends that are better for real time plotting than others?

The backend plays two roles: First, it renders everything, so the faster it renders, the faster the output. Second, the GUI toolkit used may play a role, because it may limit how fast an updated canvas is displayed. It seems "Qt5Agg" is faster than "TkAgg" for example.

Can I lower the resolution to increase FPS?

You can make the figure smaller, or use a smaller dpi. Both will decrease the amount of pixels that need to be drawn and hence speed up drawing.

Why does the FPS of my plot increase if I reduce the window size? Why does FPS drop dramatically if I switch to full screen mode?

As above, more pixels that need to be drawn on screen mean slower rendering.

Are there more things I can turn off?

We don't know what you have in your code, so we can't know what to turn off.

May turning off these buttons increase the speed?

No.

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Finally, fig.canvas.draw_idle() in itself should be sufficient to update the plot, because usually you would have the event loop running already. Restarting an event loop is not helpful.