[Qgis-user] View freezing and style

[Nyall Dawson]

On 14 February 2018 at 23:38, Enrico Fiore <enricofiore at libero.it> wrote:
>
>> Il 14 febbraio 2018 alle 12.43 Nyall Dawson <nyall.dawson at gmail.com> ha scritto:
>> >
>>
>> Let me guess - it's a point layer?
>
> yes, it is
>
>> >
>> > Can be a bug?
>>
>> Yes, it is.
>
> I have to open a ticket?

I think there's already an open ticket. I looked into this a while
ago. The culprit is this line (added in 2.16, or 2.18. I can't
recall):

https://github.com/qgis/QGIS/blob/master/src/core/layertree/qgslayertreemodel.cpp#L1524

Which is very slow to calculate, and is called for every symbol in
your layer (so 2381 times) at every map pan/zoom operation.

I only had a brief opportunity to look into it and could not find a
quick fix for this.

Nyall