[processing] Some more framework for dynamic (data defined) parameters

python/core/processing/qgsprocessingparameters.sip

@@ -376,6 +376,69 @@ class QgsProcessingParameterDefinition
  :rtype: str
 %End
 
+    bool isDynamic() const;
+%Docstring
+ Returns true if the parameter supports is dynamic, and can support data-defined values
+ (i.e. QgsProperty based values).
+.. seealso:: setIsDynamic()
+.. seealso:: dynamicPropertyDefinition()
+.. seealso:: dynamicLayerParameterName()
+ :rtype: bool
+%End
+
+    void setIsDynamic( bool dynamic );
+%Docstring
+ Sets whether the parameter is ``dynamic``, and can support data-defined values
+ (i.e. QgsProperty based values).
+.. seealso:: isDynamic()
+.. seealso:: setDynamicPropertyDefinition()
+.. seealso:: setDynamicLayerParameterName()
+%End
+
+    QgsPropertyDefinition dynamicPropertyDefinition() const;
+%Docstring
+ Returns the property definition for dynamic properties.
+.. seealso:: isDynamic()
+.. seealso:: setDynamicPropertyDefinition()
+.. seealso:: dynamicLayerParameterName()
+ :rtype: QgsPropertyDefinition
+%End
+
+    void setDynamicPropertyDefinition( const QgsPropertyDefinition &definition );
+%Docstring
+ Sets the property ``definition`` for dynamic properties.
+.. seealso:: isDynamic()
+.. seealso:: dynamicPropertyDefinition()
+.. seealso:: setDynamicLayerParameterName()
+%End
+
+    QString dynamicLayerParameterName() const;
+%Docstring
+ Returns the name of the parameter for a layer linked to a dynamic parameter, or an empty string if this is not set.
+
+ Dynamic parameters (see isDynamic()) can have an optional vector layer parameter linked to them,
+ which indicates which layer the fields and values will be available from when evaluating
+ the dynamic parameter.
+
+.. seealso:: setDynamicLayerParameterName()
+.. seealso:: isDynamic()
+.. seealso:: dynamicPropertyDefinition()
+ :rtype: str
+%End
+
+    void setDynamicLayerParameterName( const QString &name );
+%Docstring
+ Sets the ``name`` for the parameter for a layer linked to a dynamic parameter, or an empty string if this is not set.
+
+ Dynamic parameters (see isDynamic()) can have an optional vector layer parameter linked to them,
+ which indicates which layer the fields and values will be available from when evaluating
+ the dynamic parameter.
+
+.. seealso:: dynamicLayerParameterName()
+.. seealso:: isDynamic()
+.. seealso:: setDynamicPropertyDefinition()
+%End
+
   protected:
 
 
@@ -385,6 +448,9 @@ class QgsProcessingParameterDefinition
 
 
 
+
+
+
 };
 
 QFlags<QgsProcessingParameterDefinition::Flag> operator|(QgsProcessingParameterDefinition::Flag f1, QFlags<QgsProcessingParameterDefinition::Flag> f2);

src/core/processing/qgsprocessingparameters.h

@@ -412,6 +412,66 @@ class CORE_EXPORT QgsProcessingParameterDefinition
      */
     virtual QString toolTip() const;
 
+    /**
+     * Returns true if the parameter supports is dynamic, and can support data-defined values
+     * (i.e. QgsProperty based values).
+     * \see setIsDynamic()
+     * \see dynamicPropertyDefinition()
+     * \see dynamicLayerParameterName()
+     */
+    bool isDynamic() const { return mIsDynamic; }
+
+    /**
+     * Sets whether the parameter is \a dynamic, and can support data-defined values
+     * (i.e. QgsProperty based values).
+     * \see isDynamic()
+     * \see setDynamicPropertyDefinition()
+     * \see setDynamicLayerParameterName()
+     */
+    void setIsDynamic( bool dynamic ) { mIsDynamic = dynamic; }
+
+    /**
+     * Returns the property definition for dynamic properties.
+     * \see isDynamic()
+     * \see setDynamicPropertyDefinition()
+     * \see dynamicLayerParameterName()
+     */
+    QgsPropertyDefinition dynamicPropertyDefinition() const { return mPropertyDefinition; }
+
+    /**
+     * Sets the property \a definition for dynamic properties.
+     * \see isDynamic()
+     * \see dynamicPropertyDefinition()
+     * \see setDynamicLayerParameterName()
+     */
+    void setDynamicPropertyDefinition( const QgsPropertyDefinition &definition ) { mPropertyDefinition = definition; }
+
+    /**
+     * Returns the name of the parameter for a layer linked to a dynamic parameter, or an empty string if this is not set.
+     *
+     * Dynamic parameters (see isDynamic()) can have an optional vector layer parameter linked to them,
+     * which indicates which layer the fields and values will be available from when evaluating
+     * the dynamic parameter.
+     *
+     * \see setDynamicLayerParameterName()
+     * \see isDynamic()
+     * \see dynamicPropertyDefinition()
+     */
+    QString dynamicLayerParameterName() const { return mDynamicLayerParameterName; }
+
+    /**
+     * Sets the \a name for the parameter for a layer linked to a dynamic parameter, or an empty string if this is not set.
+     *
+     * Dynamic parameters (see isDynamic()) can have an optional vector layer parameter linked to them,
+     * which indicates which layer the fields and values will be available from when evaluating
+     * the dynamic parameter.
+     *
+     * \see dynamicLayerParameterName()
+     * \see isDynamic()
+     * \see setDynamicPropertyDefinition()
+     */
+    void setDynamicLayerParameterName( const QString &name ) { mDynamicLayerParameterName = name; }
+
   protected:
 
     //! Parameter name
@@ -432,6 +492,15 @@ class CORE_EXPORT QgsProcessingParameterDefinition
     //! Pointer to algorithm which owns this parameter
     QgsProcessingAlgorithm *mAlgorithm = nullptr;
 
+    //! True for dynamic parameters, which can have data-defined (QgsProperty) based values
+    bool mIsDynamic = false;
+
+    //! Data defined property definition
+    QgsPropertyDefinition mPropertyDefinition;
+
+    //! Linked vector layer parameter name for dynamic properties
+    QString mDynamicLayerParameterName;
+
     // To allow access to mAlgorithm. We don't want a public setter for this!
     friend class QgsProcessingAlgorithm;
 

tests/src/analysis/testqgsprocessing.cpp

@@ -1445,6 +1445,7 @@ void TestQgsProcessing::parameters()
   // test parameter utilities
 
   std::unique_ptr< QgsProcessingParameterDefinition > def;
+
   QVariantMap params;
   params.insert( QStringLiteral( "prop" ), QgsProperty::fromField( "a_field" ) );
   params.insert( QStringLiteral( "string" ), QStringLiteral( "a string" ) );
@@ -1471,6 +1472,13 @@ void TestQgsProcessing::parameters()
   def->setName( QStringLiteral( "bad" ) );
   QCOMPARE( QgsProcessingParameters::parameterAsString( def.get(), params, context ), QString() );
 
+  def->setIsDynamic( true );
+  QVERIFY( def->isDynamic() );
+  def->setDynamicPropertyDefinition( QgsPropertyDefinition( QStringLiteral( "Distance" ), QObject::tr( "Buffer distance" ), QgsPropertyDefinition::Double ) );
+  QCOMPARE( def->dynamicPropertyDefinition().name(), QStringLiteral( "Distance" ) );
+  def->setDynamicLayerParameterName( "parent" );
+  QCOMPARE( def->dynamicLayerParameterName(), QStringLiteral( "parent" ) );
+
   // string with dynamic property (feature not set)
   def->setName( QStringLiteral( "prop" ) );
   QCOMPARE( QgsProcessingParameters::parameterAsString( def.get(), params, context ), QString() );