Qt-interest Archive, April 2008
performance of item widgets in QTreeView (4.3.4) is HORRIBLE
Message 1 in thread
I have a custom QTreeView that has some custom item widgets (such as
sliders) assigned to one of the columns. In Qt 4.2.2, performance of
this view was excellent.
Now am I using 4.3.4 and the performance of the view is horrible. It
must be redrawing the entire view (possibly multiple times) while I drag
the sliders, because what used to be real-time feels sluggish and it
seems to take half a second to update. It gets worse the more custom
widgets are in the view.
Before I start digging through my model and the view code to see what is
getting signaled when, has anyone come across this and have any
suggestions for speeding it up?
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Message 2 in thread
Paul Miller wrote:
> I have a custom QTreeView that has some custom item widgets (such as
> sliders) assigned to one of the columns. In Qt 4.2.2, performance of
> this view was excellent.
>
> Now am I using 4.3.4 and the performance of the view is horrible. It
> must be redrawing the entire view (possibly multiple times) while I drag
> the sliders, because what used to be real-time feels sluggish and it
> seems to take half a second to update. It gets worse the more custom
> widgets are in the view.
>
> Before I start digging through my model and the view code to see what is
> getting signaled when, has anyone come across this and have any
> suggestions for speeding it up?
Found it! I was refreshing my custom widgets too frequently. My bad!
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Message 3 in thread
Paul Miller wrote:
> Paul Miller wrote:
>> I have a custom QTreeView that has some custom item widgets (such as
>> sliders) assigned to one of the columns. In Qt 4.2.2, performance of
>> this view was excellent.
>>
>> Now am I using 4.3.4 and the performance of the view is horrible. It
>> must be redrawing the entire view (possibly multiple times) while I
>> drag the sliders, because what used to be real-time feels sluggish and
>> it seems to take half a second to update. It gets worse the more
>> custom widgets are in the view.
>>
>> Before I start digging through my model and the view code to see what
>> is getting signaled when, has anyone come across this and have any
>> suggestions for speeding it up?
>
> Found it! I was refreshing my custom widgets too frequently. My bad!
Ok, it's still very slow when scrolling the tree or expanding/collapsing
groups. In general, refreshing the entire tree seems to take about 50x
longer than in 4.2.2, with the same code on my end.
Anyone else seen this?
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