The improvement allows immediate cancellation of raster rendering
in progress. Until now, even when map rendering got cancelled
(e.g. by zooming of panning canvas), the GUI got blocked while waiting
for raster layers to finish their rendering (only vector layers have
had support for cancellation). This should allow for much smoother
user experience while browsing maps including rasters.
The cancellation is supported currently by WMS/WMTS and WCS providers.
GDAL provider may also get support thanks to improvements in GDAL 2.
Funded by Land Information New Zealand.
Rationale:
- there was a lot of large objects passed by value, so potentially
there's a speed bump from this
- even for implicitly shared classes like QString/QList there's still
a (small) cost for copying the objects when there's no reason to
- it's the right thing to do!
- update methods of existing classes
- add comment to methods missing in the sip bindings
- split up collective sip files into single files and use
same directory structure in python/ as in src/
- add a lot of missing classes (some might not make sense because of
missing python methods in those classes)
- remove some non-existing methods from the header files
- add scripts/sipdiff
- replace some usages of std::vector and std::set with QVector/QSet
