How to query whether event queue has been flushed

Question

Peter O'Connor 2011-2-11

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https://ww2.mathworks.cn/matlabcentral/answers/1217-how-to-query-whether-event-queue-has-been-flushed

I've got a callback function that's called Post-Set to the axes X-lim property. The Xlim is changed by everything, including title and xlabel, so I want this callback function only be active after everything is displayed (ie if the event queue has been flushed). Basically, I've got an if at the start of the callback function, and i need it to query whether matlab has displayed the plot and is just waiting, or is still running. It's just a boolean, and it should be somewhere, but I can't fine the damn thing!

Any ideas?

Thanks,

-Peter

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Jimy Shah 2011-2-12

DRAWNOW does not help? It should technically flush the event queue. If that's not helpful, can you send some example code demonstrating your issue?

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Answer 1

Peter O'Connor 2011-2-15

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https://ww2.mathworks.cn/matlabcentral/answers/1217-how-to-query-whether-event-queue-has-been-flushed#answer_2025

Hey-- idea was not to flush the event queue, but to check if it had been flushed.

It was for an axes-limits listener callback, which plotted a different amount of data depending on the axes limits. Problem was a ton of functions (xlabel, label, title, etc..) slightly reset the axes limits, causing the callback to execute and the data to be recomputed like 20 times before the plot was even shown.

Ended up using sort of a hack to get around it with dbstack, only letting it through if the parent function was pan or zoom.

So, still an open question, and possibly a feature addition- how do you check the event queue?