[processing] Allow algorithms to provide additional configuration widgets

python/core/processing/qgsprocessingalgorithm.sip.in

@@ -10,12 +10,10 @@
 
 
 
-
 %ModuleHeaderCode
 #include <qgsprocessingmodelalgorithm.h>
 %End
 
-
 class QgsProcessingAlgorithm
 {
 %Docstring
@@ -351,6 +349,12 @@ If an algorithm subclass implements a custom parameters widget, a copy of this w
 should be constructed and returned by this method.
 The base class implementation returns None, which indicates that an autogenerated
 parameters widget should be used.
+%End
+
+    virtual QgsProcessingAlgorithmConfigurationWidget *createModelerWidget() const /Factory/;
+%Docstring
+If an algorithm subclass implements a configuration widget for the algorithm itself,
+a new instance of this widget should be returned by this method.
 %End
 
     QgsExpressionContext createExpressionContext( const QVariantMap &parameters,

python/plugins/processing/modeler/ModelerGraphicItem.py

@@ -208,7 +208,7 @@ class ModelerGraphicItem(QGraphicsItem):
                 self.scene.dialog.repaintModel()
         elif isinstance(self.element, QgsProcessingModelChildAlgorithm):
             elemAlg = self.element.algorithm()
-            dlg = ModelerParametersDialog(elemAlg, self.model, self.element.childId())
+            dlg = ModelerParametersDialog(elemAlg, self.model, self.element.childId(), self.element.configuration())
             if dlg.exec_():
                 alg = dlg.createAlgorithm()
                 alg.setChildId(self.element.childId())

python/plugins/processing/modeler/ModelerParametersDialog.py

@@ -63,13 +63,15 @@ from processing.gui.MultipleInputPanel import MultipleInputPanel
 
 
 class ModelerParametersDialog(QDialog):
-    def __init__(self, alg, model, algName=None):
+
+    def __init__(self, alg, model, algName=None, configuration=None):
         QDialog.__init__(self)
         self.setModal(True)
 
         self._alg = alg # The algorithm to define in this dialog. It is an instance of QgsProcessingAlgorithm
         self.model = model # The model this algorithm is going to be added to. It is an instance of QgsProcessingModelAlgorithm
         self.childId = algName # The name of the algorithm in the model, in case we are editing it and not defining it for the first time
+        self.configuration = configuration
 
         self.setupUi()
         self.params = None
@@ -87,6 +89,8 @@ class ModelerParametersDialog(QDialog):
         self.wrappers = {}
         self.valueItems = {}
         self.dependentItems = {}
+        self.algorithmItem = None
+
         self.resize(650, 450)
         self.buttonBox = QDialogButtonBox()
         self.buttonBox.setOrientation(Qt.Horizontal)
@@ -114,6 +118,10 @@ class ModelerParametersDialog(QDialog):
         line.setFrameShape(QFrame.HLine)
         line.setFrameShadow(QFrame.Sunken)
         self.verticalLayout.addWidget(line)
+        self.algorithmItem = self._alg.createModelerWidget()
+        if self.configuration:
+            self.algorithmItem.setConfiguration(self.configuration)
+        self.verticalLayout.addWidget(self.algorithmItem)
 
         for param in self._alg.parameterDefinitions():
             if param.flags() & QgsProcessingParameterDefinition.FlagAdvanced:
@@ -284,6 +292,8 @@ class ModelerParametersDialog(QDialog):
         else:
             alg.setChildId(self.childId)
         alg.setDescription(self.descriptionBox.text())
+        if self.algorithmItem:
+            alg.setConfiguration(self.algorithmItem.configuration())
         for param in self._alg.parameterDefinitions():
             if param.isDestination() or param.flags() & QgsProcessingParameterDefinition.FlagHidden:
                 continue

src/core/processing/qgsprocessingalgorithm.cpp

@@ -131,6 +131,11 @@ QWidget *QgsProcessingAlgorithm::createCustomParametersWidget( QWidget * ) const
   return nullptr;
 }
 
+QgsProcessingAlgorithmConfigurationWidget *QgsProcessingAlgorithm::createModelerWidget() const
+{
+  return nullptr;
+}
+
 QgsExpressionContext QgsProcessingAlgorithm::createExpressionContext( const QVariantMap &parameters,
     QgsProcessingContext &context, QgsProcessingFeatureSource *source ) const
 {

src/core/processing/qgsprocessingalgorithm.h

@@ -33,7 +33,8 @@ class QgsProcessingProvider;
 class QgsProcessingFeedback;
 class QgsFeatureSink;
 class QgsProcessingFeedback;
-
+class QgsProcessingModelAlgorithm;
+class QgsProcessingAlgorithmConfigurationWidget;
 
 #ifdef SIP_RUN
 % ModuleHeaderCode
@@ -41,7 +42,6 @@ class QgsProcessingFeedback;
 % End
 #endif
 
-
 /**
  * \class QgsProcessingAlgorithm
  * \ingroup core
@@ -356,6 +356,12 @@ class CORE_EXPORT QgsProcessingAlgorithm
      */
     virtual QWidget *createCustomParametersWidget( QWidget *parent = nullptr ) const SIP_FACTORY;
 
+    /**
+     * If an algorithm subclass implements a configuration widget for the algorithm itself,
+     * a new instance of this widget should be returned by this method.
+     */
+    virtual QgsProcessingAlgorithmConfigurationWidget *createModelerWidget() const SIP_FACTORY;
+
     /**
      * Creates an expression context relating to the algorithm. This can be called by algorithms
      * to create a new expression context ready for evaluating expressions within the algorithm.