Unresponsive plotWidget after many updates

[Brandon du Toit]

Hi,

I have two 2x3 QGridlayouts containing plotWidgets, each on a QTabWidget tab. I plot to and clear these plotWidgets frequently and after a few plot/clear sequences a random few of them lose their interactiveness. I can no longer interactively drag to pan them or scroll to zoom in/out on them. If I drag to pan or scroll to zoom, I have to switch to the other tab and back for the change to show on the plot.

I use plotWidget.clear() to clear the plots and plotWidget.plot() to plot traces. Using pyqtgraph v0.12.3, python3.8 64 bit PyQt5 v5.15.6

Thanks

[Martin Chase]

Hey,

If it's possible, modifying the data in place and calling `PlotWidget.update()` is much more performant, rather than clearing and re-plotting each time. I started investigating the plot/clear behavior, and indeed see occasional lockups and possibly even a leak of some sort, but the modify-in-place architecture doesn't seem to suffer from the same.

Here's an example of what I mean:

x = np.linspace(0, 0.8, numpts)
y = np.random.random(size=numpts) * 0.8
plot.plot(x=x, y=y)
# ... later, we modify in place
y[:] = np.random.random(size=numpts) * 0.8
plot.update()