[Qgis-developer] Symbol levels

[Martin Dobias]

Hi Hugo

On Tue, Apr 15, 2014 at 3:07 PM, Hugo Mercier <hugo.mercier at oslandia.com> wrote:
>
> The UI asks for numeric levels, but, if I am correct, only relative
> orders between two symbol layers are important.
> Was there something else originally planned ? Something like a global
> level to be able to order symbol layers of different vector layers ?

No, it was meant just for levels within one layer.


> Another point : apart from performance issue, I cannot see any reason
> why *not* to enable symbol levels. Are there situations were users do
> want different symbol layers to overlap ?

I think there are such situations, from the top of my head:
- with symbol levels you cannot see the rendering progress (everything
is rendered at the end) - this makes quite a difference with big
layers
- you don't always want the symbol layers to be blended (different appearance)
- not all renderers need to support symbol levels

I don't think we should go with symbol levels always on.

Regards
Martin