Class: QgsRenderedFeatureHandlerInterface¶
- class qgis.core.QgsRenderedFeatureHandlerInterface¶
Bases:
sip.wrapper
An interface for classes which provider custom handlers for features rendered as part of a map render job.
QgsRenderedFeatureHandlerInterface
objects are registered in theQgsMapSettings
objects used to construct map render jobs. During the rendering operation, thehandleRenderedFeature()
method will be called once for every rendered feature, allowing the handler to perform some custom task based on the provided information.They can be used for custom tasks which operate on a set of rendered features, such as creating spatial indexes of the location and rendered symbology bounding box of all features rendered on a map.
New in version 3.10:
Methods
Called whenever a
feature
is rendered during a map render job.Returns a list of attributes required by this handler, for the specified
layer
.- class RenderedFeatureContext(renderContext: QgsRenderContext)¶
Bases:
sip.wrapper
Constructor for RenderedFeatureContext.
- Parameters:
renderContext – The render context which was used while rendering feature.
QgsRenderedFeatureHandlerInterface.RenderedFeatureContext(QgsRenderedFeatureHandlerInterface.RenderedFeatureContext)
The render context which was used while rendering feature.
- renderContext¶
- handleRenderedFeature(self, feature: QgsFeature, renderedBounds: QgsGeometry, context: QgsRenderedFeatureHandlerInterface.RenderedFeatureContext)¶
Called whenever a
feature
is rendered during a map render job.The
renderedBounds
argument specifies the (approximate) bounds of the rendered feature’s symbology. E.g. for point geometry features, this will be the bounding box of the marker symbol used to symbolize the point.renderedBounds
geometries are specified in painter units (not map units).Warning
This method may be called from many different threads (for multi-threaded map render operations), and accordingly care must be taken to ensure that
handleRenderedFeature()
implementations are appropriately thread safe.The
context
argument is used to provide additional context relating to the rendering of a feature.- Parameters:
feature (QgsFeature) –
renderedBounds (QgsGeometry) –
context (QgsRenderedFeatureHandlerInterface.RenderedFeatureContext) –
- usedAttributes(self, layer: QgsVectorLayer, context: QgsRenderContext) Set[str] ¶
Returns a list of attributes required by this handler, for the specified
layer
. Attributes not listed in here may not be requested from the provider at rendering time.- Parameters:
layer (QgsVectorLayer) –
context (QgsRenderContext) –
- Return type:
Set[str]