Another bit in the project refactoring work to get rid of dependencies
on QgsProject singleton.
Reading of layer trees from XML is now split into two phases:
1. read XML and keep layer IDs
2. resolve layer IDs to QgsMapLayer instances (using QgsProject)
There are convenience methods to do both phases in one go.
See https://github.com/qgis/QGIS-Enhancement-Proposals/issues/86
- Checking/unchecking a group doesn't change the check state of its children.
A node is visible if and only if it is checked and all its parents too.
- There is no more a semi-checked state for a group
- Ctrl-clic on a unchecked group will check the group and all its descendants.
- Ctrl-clic on a unchecked layer will check the lager and all its parents.
- Ctrl-clic on a checked group will uncheck the group and all its descendants.
- Ctrl-clic on a checked layer will uncheck the layer and all its parents.
- Those actions are available in contextual menu items in the tree view.
- Invisible layers because they or their parent(s) is unchecked are greyed out.
- rename methods with XML to Xml, CRS to Crs, WMS to Wms, ID to Id
- rename methods with SRS to Crs
- rename methods with abbreviations like "dest" to "destination"
- rename methods with abbreviations like "src" to "source"
Now all classes and members are either exposed to bindings or marked
as "not available in Python bindings" in the docs.
Drop test thresholds to 0. Now it should be much easier to determine
what missing members have been added which are causing test
failures.
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!
