Adds new methods overloads to QgsVectorLayer
getFeatures( expression )
getFeatures( ids )
getFeature( id )
These three methods to query features are by far the most used ones
and with this patch it is much easier to write and read code.
- add selectByRect( QgsRectangle&, SelectBehaviour) and
selectByIds( QgsFeatureIds, SelectBehaviour) for selecting
by rect and ids respectively, with options to add to selection/
remove from selection/intersect with current selection
- deprecate select( QgsRectangle ) and setSelectedFeatures in
favour of new methods
- add unit tests
Makes it simple for scripts to select by expression. The method
also accepts a parameter which dictates whether matching features
are added to an existing selection, removed from the selection
or intersected with the current selection.
The existing code from the select by expression dialog has been
moved to QgsVectorLayer, and optimised for maximum possible speed.
Also added unit tests.
This commit adds a number of different forms of aggregates to
the expression engine.
1. Aggregates within the current layer, eg sum("passengers")
Supports sub expressions (ie sum("passengers"/2) ), group by
( sum("passengers", group_by:="line_segment") ), and optional
filters ( sum("passengers", filter:= "station_class" > 3 ) )
2. Relational aggregates, which calculate an aggregate over
all matching child features from a relation, eg
relation_aggregate( 'my_relation', 'mean', "some_child_field" )
3. A summary aggregate function, for calculating aggregates
on other layers. Eg aggregate('rail_station_layer','sum',"passengers")
The summary aggregate function supports an optional filter,
making it possible to calculate things like:
aggregate('rail_stations','sum',"passengers",
intersects(@atlas_geometry, $geometry ) )
for calculating the total number of passengers for the stations
inside the current atlas feature
In all cases the calculations are cached inside the expression
context, so they only need to be calculated once for each
set of expression evaluations.
Sponsored by Kanton of Zug, Switzerland
The original name was not representative for the scope of the class
and misleading at best.
The class manages actions for a given layer and it's not a single action
like the former name suggested.
There is a typedef introduced to keep it in the API until we can remove
it with QGIS 3.
The current approach of testing !vl || vl->geometryType() != NoGeometry
is not intuitive and has been the source of 2 recent bugs.
Replacing these tests with the new isSpatial() function makes it
immediately obvious what is being tested. It also allows for
non-spatial plugin layers to be correctly handled by overriding
this method.
This check tests that if a function has been declared deprecated
with either Q_DECL_DEPRECATED or has a @deprecated Doxygen note
then it MUST have both the Q_DECL_DEPRECATD and @deprecated note.
It's important that both are used, as Q_DECL_DEPRECATED allows
throwing a warning if that method is used in code, while the
@deprecated doxygen note gives an indication to devs/PyQGIS users
of why it's deprecated and what should be used instead.
Ideally we'd also test for SIP /Deprecated/ tags, but I can't
find any reliable way to do this.
* make sip coverage test aware that there are less classes where QSci sip
headers are not available
* exclude properties from members
* fix QgsFeatureIds typedef (fixes missing signal
QgsVectorLayer.featuresDeleted and others)
* add missing notes for PyNames
* include some missing new methods in bindings
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!
- call reserve on container classes where applicable
- make sure Q_FOREACH uses references
- remove dynamic casts to base classes
- fix some implicit bool conversions
