[Qt-interest] QSlider::setValue() causing delays in QTimer event delivery

[Josiah Bryan]

Frank Hemer wrote:
>>> ...
>>> If this really is due to the slider update increasing latency within the
>>> event queue then a possible, if not ideal solution would be to implement
>>> your own slider-like widget or other progress indicator and do everything
>>> you can to get it running quickly enough that it completes in less than
>>> the ~33ms or so required for 30fps video (on some minimum target hardware
>>> performance profile).
>> I'm crossing my fingers on that one - the last thing I want to do is
>> implement a custom slider from scratch! :-) But, I may have to when it's
>> all said and done. We'll see.
> 
> Hmm - just to eliminate the obvious: Make sure there are no slots connected to 
> the QAbstractSliders signals that might cause the delay ...
> 

Good point... there is a single slot from my code that I connect to the 
slider, for when the user drags the slider. However, that slot is locked 
with a boolean flag (e.g. if m_inPollingMethod - return), so the slot 
essentially does nothing. However, that slot shouldn't have been called 
during testing when blockSignals() was turned on - I didn't check it 
though.

-josiah

-- 

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Josiah Bryan
Productive Concepts, Inc.
jbryan at pciint.com
(765) 964-6009, ext. 224