Improve dox

python/core/processing/qgsprocessingalgorithm.sip

@@ -777,6 +777,8 @@ class QgsProcessingFeatureBasedAlgorithm : QgsProcessingAlgorithm
  Maps the input WKB geometry type (``inputWkbType``) to the corresponding
  output WKB type generated by the algorithm. The default behavior is that the algorithm maintains
  the same WKB type.
+ This is called once by the base class when creating the output sink for the algorithm (i.e. it is
+ not called once per feature processed).
  :rtype: QgsWkbTypes.Type
 %End
 
@@ -787,6 +789,9 @@ class QgsProcessingFeatureBasedAlgorithm : QgsProcessingAlgorithm
  the same fields as are input.
  Algorithms which add, remove or modify existing fields should override this method and
  implement logic here to indicate which fields are output by the algorithm.
+
+ This is called once by the base class when creating the output sink for the algorithm (i.e. it is
+ not called once per feature processed).
  :rtype: QgsFields
 %End
 
@@ -795,6 +800,9 @@ class QgsProcessingFeatureBasedAlgorithm : QgsProcessingAlgorithm
  Maps the input source coordinate reference system (``inputCrs``) to a corresponding
  output CRS generated by the algorithm. The default behavior is that the algorithm maintains
  the same CRS as the input source.
+
+ This is called once by the base class when creating the output sink for the algorithm (i.e. it is
+ not called once per feature processed).
  :rtype: QgsCoordinateReferenceSystem
 %End
 

src/core/processing/qgsprocessingalgorithm.h

@@ -752,6 +752,8 @@ class CORE_EXPORT QgsProcessingFeatureBasedAlgorithm : public QgsProcessingAlgor
      * Maps the input WKB geometry type (\a inputWkbType) to the corresponding
      * output WKB type generated by the algorithm. The default behavior is that the algorithm maintains
      * the same WKB type.
+     * This is called once by the base class when creating the output sink for the algorithm (i.e. it is
+     * not called once per feature processed).
      */
     virtual QgsWkbTypes::Type outputWkbType( QgsWkbTypes::Type inputWkbType ) const { return inputWkbType; }
 
@@ -761,13 +763,19 @@ class CORE_EXPORT QgsProcessingFeatureBasedAlgorithm : public QgsProcessingAlgor
      * the same fields as are input.
      * Algorithms which add, remove or modify existing fields should override this method and
      * implement logic here to indicate which fields are output by the algorithm.
+     *
+     * This is called once by the base class when creating the output sink for the algorithm (i.e. it is
+     * not called once per feature processed).
      */
     virtual QgsFields outputFields( const QgsFields &inputFields ) const { return inputFields; }
 
     /**
      * Maps the input source coordinate reference system (\a inputCrs) to a corresponding
      * output CRS generated by the algorithm. The default behavior is that the algorithm maintains
      * the same CRS as the input source.
+     *
+     * This is called once by the base class when creating the output sink for the algorithm (i.e. it is
+     * not called once per feature processed).
      */
     virtual QgsCoordinateReferenceSystem outputCrs( const QgsCoordinateReferenceSystem &inputCrs ) const { return inputCrs; }