[Qgis-developer] Questions regarding new geometry engine

[Nyall Dawson]

Hi Marco (also cc-ing dev list)

I've been looking over the new geometry engine and it's really nice
stuff. It's fantastic to have this in QGIS and it's a huge improvement
over the old geometry class. Thank you!

I have a couple of questions regarding this which I'm hoping you can
clarify for me. Firstly, I *think* that there's an issue with the
inheritance of some of the classes. Specifically QgsMultiLineStringV2
and QgsMultiPolygonV2. Currently both of these derive from
QgsGeometryCollectionV2, but I think they should derive from
QgsMultiCurveV2 and QgsMultiSurfaceV2. This would seem logical to me
since QgsLineStringV2 derives from QgsCurveV2 and QgsPolygonV2 derives
from QgsCurvePolygonV2. It also would match with how I understand the
OGC simple features access specification describes (see 6.1.8.1 -
MultiCurve should be non-instantiable, 6.1.9 multiline is a
multicurve, and 6.1.13.1 and 6.1.14 for the corresponding
multisurface/multipolygon types). What's your thoughts?

Secondly, are you able to share your plans for bug fixing leading up
to 2.10? There's a number of serious regressions following this work,
and I'm wondering if I should be focusing on these during the
sponsored bug fixing or whether you plan to tackle them before
release? The biggest issues I see are:
- #12836 : layers fail to render
- unfiled: I get a lot of unknown exceptions when working with
geometries. I can reproduce this consistently by trying to use the
reshape tool on a polygon, or by rotating a map within the canvas or a
composer.
- #12843: simplify tool broken
- i noticed there's also a number of stubbed methods in geometry with
todo comments (eg QgsGeometry::buffer ).

If you can share your plans then I can plan my work accordingly.

Again, thanks again for this fantastic work!

Nyall