[Qgis-developer] Bringing diagrams into labeling-ng

[Martin Dobias]

Hi Marco

On Tue, Feb 15, 2011 at 10:16 AM, Marco Hugentobler
<marco.hugentobler at sourcepole.ch> wrote:
> Hi devs
>
> One thing that I wanted to do already some time ago was to bring the diagrams
> together with the pal instance that does the labeling (ng). Currently, the
> diagrams use a different pal instance and the conflict resolution does not
> detect overlaps between diagrams and labels. Also, it would be cool to use the
> label move tools for diagrams and labels.

Yes this is surely a good idea. It would simplify the whole thing.


> Therefore I'm proposing a change to QgsPalLabeling. To make the system more
> extensible, it would be good to have QgsPalGeometry as an abstract base class
> and derive QgsPalLabelGeometry from it (and diagram specific classes later
> too). Each QgsPalGeometry would implement size calculation and drawing in its
> specific way.
>
> Any objections or better ideas?

I'm not really sure I understand the concept. Could you please explain
the implications of that transition?
- what will happen to the vector overlays? will that be deprecated or
kept? (AFAIK the vector overlay stuff is used just by the diagrams
plugin, so it might be a good idea to integrate diagrams directly to
PAL so simplify the whole post-rendering routine).
- what would be the impact on the labeling itself?

Regards
Martin