Class: QgsAbstractFeatureIteratorFromSourceQgsVectorLayerFeatureSourceBase

class qgis.core.QgsAbstractFeatureIteratorFromSourceQgsVectorLayerFeatureSourceBase

Bases: QgsAbstractFeatureIterator

Helper template that cares of two things: 1. automatic deletion of source if owned by iterator, 2. notification of open/closed iterator.

Note

not available in Python bindings (although present in SIP file)

Methods

deref

Remove reference, delete if refs == 0

fetchFeature

If you write a feature iterator for your provider, this is the method you need to implement!!

filterRectToSourceCrs

Returns a rectangle representing the original request’s QgsFeatureRequest.filterRect().

geometryToDestinationCrs

Transforms feature’s geometry according to the specified coordinate transform.

iteratorClosed

to be called by from subclass in close()

nextFeatureFilterExpression

By default, the iterator will fetch all features and check if the feature matches the expression.

nextFeatureFilterFids

By default, the iterator will fetch all features and check if the id is in the request.

prepareSimplification

Setup the simplification of geometries to fetch using the specified simplify method

ref

Add reference

deref(self)

Remove reference, delete if refs == 0

fetchFeature(self, f: QgsFeature) bool

If you write a feature iterator for your provider, this is the method you need to implement!!

Parameters

f – The feature to write to

Returns

True if a feature was written to f

filterRectToSourceCrs(self, transform: QgsCoordinateTransform) QgsRectangle

Returns a rectangle representing the original request’s QgsFeatureRequest.filterRect(). If transform is a valid coordinate transform, the return rectangle will represent the requested filterRect() transformed to the source’s coordinate reference system. Iterators should call this method and use the returned rectangle for filtering features to ensure that any QgsFeatureRequest.destinationCrs() set on the request is respected. Will throw a QgsCsException if the rect cannot be transformed from the destination CRS.

New in version 3.0.

geometryToDestinationCrs(self, feature: QgsFeature, transform: QgsCoordinateTransform)

Transforms feature’s geometry according to the specified coordinate transform. If feature has no geometry or transform is invalid then calling this method has no effect and will be shortcut. Iterators should call this method before returning features to ensure that any QgsFeatureRequest.destinationCrs() set on the request is respected.

New in version 3.0.

iteratorClosed(self)

to be called by from subclass in close()

nextFeatureFilterExpression(self, f: QgsFeature) bool

By default, the iterator will fetch all features and check if the feature matches the expression. If you have a more sophisticated metodology (SQL request for the features…) and you check for the expression in your fetchFeature method, you can just redirect this call to fetchFeature so the default check will be omitted.

Parameters

f – The feature to write to

Returns

True if a feature was written to f

nextFeatureFilterFids(self, f: QgsFeature) bool

By default, the iterator will fetch all features and check if the id is in the request. If you have a more sophisticated metodology (SQL request for the features…) and you are sure, that any feature you return from fetchFeature will match if the request was FilterFids you can just redirect this call to fetchFeature so the default check will be omitted.

Parameters

f – The feature to write to

Returns

True if a feature was written to f

prepareSimplification(self, simplifyMethod: QgsSimplifyMethod) bool

Setup the simplification of geometries to fetch using the specified simplify method

ref(self)

Add reference