If a rule is not available on the system (eg geos too old):

- grey out the rule in the rules list - show an explanatory tooltip - don't allow users to create copies of that rule
qgis · Sep 10, 2024 · 569da98 · 569da98
1 parent 1c44fcd
commit 569da98
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Showing 14 changed files with 110 additions and 4 deletions.
diff --git a/python/PyQt6/core/auto_generated/labeling/rules/qgslabelingenginerule.sip.in b/python/PyQt6/core/auto_generated/labeling/rules/qgslabelingenginerule.sip.in
@@ -145,6 +145,16 @@ Returns a string uniquely identifying the rule subclass.
     virtual QString displayType() const = 0;
 %Docstring
 Returns a user-friendly, translated string representing the rule type.
+%End
+
+    virtual bool isAvailable() const;
+%Docstring
+Returns ``True`` if the rule is available for use within the current QGIS environment.
+
+The base class method returns ``True``.
+
+Rules can return ``False`` if required dependencies are not available, e.g. if a library version
+is too old for the rule.
 %End
 
     virtual QString description() const;

diff --git a/python/PyQt6/core/auto_generated/labeling/rules/qgslabelingenginerule_impl.sip.in b/python/PyQt6/core/auto_generated/labeling/rules/qgslabelingenginerule_impl.sip.in
@@ -32,6 +32,8 @@ Base class for labeling engine rules which prevents labels being placed too clos
 
     virtual void resolveReferences( const QgsProject *project );
 
+    virtual bool isAvailable() const;
+
 
     QgsMapLayer *labeledLayer() const;
 %Docstring
@@ -242,6 +244,8 @@ A labeling engine rule which prevents labels being placed too close to labels fr
 
     virtual QString description() const;
 
+    virtual bool isAvailable() const;
+
     virtual void writeXml( QDomDocument &doc, QDomElement &element, const QgsReadWriteContext &context ) const;
 
     virtual void readXml( const QDomElement &element, const QgsReadWriteContext &context );

diff --git a/python/PyQt6/core/auto_generated/labeling/rules/qgslabelingengineruleregistry.sip.in b/python/PyQt6/core/auto_generated/labeling/rules/qgslabelingengineruleregistry.sip.in
@@ -45,6 +45,14 @@ Returns a list of the rule IDs for rules present in the registry.
     QString displayType( const QString &id ) const;
 %Docstring
 Returns a user-friendly, translated string representing the rule type with matching ``id``.
+%End
+
+    bool isAvailable( const QString &id ) const;
+%Docstring
+Returns ``True`` if the rule is with matching ``id`` is available for use within the current QGIS environment.
+
+Rules can return ``False`` if required dependencies are not available, e.g. if a library version
+is too old for the rule.
 %End
 
     QgsAbstractLabelingEngineRule *create( const QString &id ) const /TransferBack/;

diff --git a/python/core/auto_generated/labeling/rules/qgslabelingenginerule.sip.in b/python/core/auto_generated/labeling/rules/qgslabelingenginerule.sip.in
@@ -145,6 +145,16 @@ Returns a string uniquely identifying the rule subclass.
     virtual QString displayType() const = 0;
 %Docstring
 Returns a user-friendly, translated string representing the rule type.
+%End
+
+    virtual bool isAvailable() const;
+%Docstring
+Returns ``True`` if the rule is available for use within the current QGIS environment.
+
+The base class method returns ``True``.
+
+Rules can return ``False`` if required dependencies are not available, e.g. if a library version
+is too old for the rule.
 %End
 
     virtual QString description() const;

diff --git a/python/core/auto_generated/labeling/rules/qgslabelingenginerule_impl.sip.in b/python/core/auto_generated/labeling/rules/qgslabelingenginerule_impl.sip.in
@@ -32,6 +32,8 @@ Base class for labeling engine rules which prevents labels being placed too clos
 
     virtual void resolveReferences( const QgsProject *project );
 
+    virtual bool isAvailable() const;
+
 
     QgsMapLayer *labeledLayer() const;
 %Docstring
@@ -242,6 +244,8 @@ A labeling engine rule which prevents labels being placed too close to labels fr
 
     virtual QString description() const;
 
+    virtual bool isAvailable() const;
+
     virtual void writeXml( QDomDocument &doc, QDomElement &element, const QgsReadWriteContext &context ) const;
 
     virtual void readXml( const QDomElement &element, const QgsReadWriteContext &context );

diff --git a/python/core/auto_generated/labeling/rules/qgslabelingengineruleregistry.sip.in b/python/core/auto_generated/labeling/rules/qgslabelingengineruleregistry.sip.in
@@ -45,6 +45,14 @@ Returns a list of the rule IDs for rules present in the registry.
     QString displayType( const QString &id ) const;
 %Docstring
 Returns a user-friendly, translated string representing the rule type with matching ``id``.
+%End
+
+    bool isAvailable( const QString &id ) const;
+%Docstring
+Returns ``True`` if the rule is with matching ``id`` is available for use within the current QGIS environment.
+
+Rules can return ``False`` if required dependencies are not available, e.g. if a library version
+is too old for the rule.
 %End
 
     QgsAbstractLabelingEngineRule *create( const QString &id ) const /TransferBack/;

diff --git a/src/core/labeling/qgslabelingengine.cpp b/src/core/labeling/qgslabelingengine.cpp
@@ -107,7 +107,7 @@ bool QgsLabelingEngine::prepare( QgsRenderContext &context )
   bool res = true;
   for ( const QgsAbstractLabelingEngineRule *rule : rules )
   {
-    if ( !rule->active() )
+    if ( !rule->active() || !rule->isAvailable() )
       continue;
 
     std::unique_ptr< QgsAbstractLabelingEngineRule > ruleClone( rule->clone() );

diff --git a/src/core/labeling/rules/qgslabelingenginerule.cpp b/src/core/labeling/rules/qgslabelingenginerule.cpp
@@ -83,6 +83,11 @@ void QgsAbstractLabelingEngineRule::copyCommonProperties( QgsAbstractLabelingEng
   other->mIsActive = mIsActive;
 }
 
+bool QgsAbstractLabelingEngineRule::isAvailable() const
+{
+  return true;
+}
+
 QString QgsAbstractLabelingEngineRule::description() const
 {
   return mName.isEmpty() ? displayType() : mName;

diff --git a/src/core/labeling/rules/qgslabelingenginerule.h b/src/core/labeling/rules/qgslabelingenginerule.h
@@ -178,6 +178,16 @@ class CORE_EXPORT QgsAbstractLabelingEngineRule
      */
     virtual QString displayType() const = 0;
 
+    /**
+     * Returns TRUE if the rule is available for use within the current QGIS environment.
+     *
+     * The base class method returns TRUE.
+     *
+     * Rules can return FALSE if required dependencies are not available, e.g. if a library version
+     * is too old for the rule.
+     */
+    virtual bool isAvailable() const;
+
     /**
      * Returns a user-friendly description of the rule.
      *

diff --git a/src/core/labeling/rules/qgslabelingenginerule_impl.cpp b/src/core/labeling/rules/qgslabelingenginerule_impl.cpp
@@ -136,6 +136,15 @@ void QgsAbstractLabelingEngineRuleDistanceFromFeature::alterCandidateCost( pal::
   }
 }
 
+bool QgsAbstractLabelingEngineRuleDistanceFromFeature::isAvailable() const
+{
+#if GEOS_VERSION_MAJOR>3 || ( GEOS_VERSION_MAJOR == 3 && GEOS_VERSION_MINOR>=10 )
+  return true;
+#else
+  return false;
+#endif
+}
+
 QgsMapLayer *QgsAbstractLabelingEngineRuleDistanceFromFeature::labeledLayer() const
 {
   return mLabeledLayer.get();
@@ -354,6 +363,15 @@ QString QgsLabelingEngineRuleMinimumDistanceLabelToLabel::description() const
   return res;
 }
 
+bool QgsLabelingEngineRuleMinimumDistanceLabelToLabel::isAvailable() const
+{
+#if GEOS_VERSION_MAJOR>3 || ( GEOS_VERSION_MAJOR == 3 && GEOS_VERSION_MINOR>=10 )
+  return true;
+#else
+  return false;
+#endif
+}
+
 void QgsLabelingEngineRuleMinimumDistanceLabelToLabel::writeXml( QDomDocument &, QDomElement &element, const QgsReadWriteContext & ) const
 {
   element.setAttribute( QStringLiteral( "distance" ), mDistance );

diff --git a/src/core/labeling/rules/qgslabelingenginerule_impl.h b/src/core/labeling/rules/qgslabelingenginerule_impl.h
@@ -43,6 +43,7 @@ class CORE_EXPORT QgsAbstractLabelingEngineRuleDistanceFromFeature : public QgsA
     void resolveReferences( const QgsProject *project ) override;
     bool candidateIsIllegal( const pal::LabelPosition *candidate, QgsLabelingEngineContext &context ) const override SIP_SKIP;
     void alterCandidateCost( pal::LabelPosition *candidate, QgsLabelingEngineContext &context ) const override SIP_SKIP;
+    bool isAvailable() const override;
 
     /**
      * Returns the layer providing the labels.
@@ -262,6 +263,7 @@ class CORE_EXPORT QgsLabelingEngineRuleMinimumDistanceLabelToLabel : public QgsA
     QString id() const override;
     QString displayType() const override;
     QString description() const override;
+    bool isAvailable() const override;
     void writeXml( QDomDocument &doc, QDomElement &element, const QgsReadWriteContext &context ) const override;
     void readXml( const QDomElement &element, const QgsReadWriteContext &context ) override;
     void resolveReferences( const QgsProject *project ) override;

diff --git a/src/core/labeling/rules/qgslabelingengineruleregistry.cpp b/src/core/labeling/rules/qgslabelingengineruleregistry.cpp
@@ -47,6 +47,15 @@ QString QgsLabelingEngineRuleRegistry::displayType( const QString &id ) const
   return it->second->displayType();
 }
 
+bool QgsLabelingEngineRuleRegistry::isAvailable( const QString &id ) const
+{
+  auto it = mRules.find( id );
+  if ( it == mRules.end() )
+    return false;
+
+  return it->second->isAvailable();
+}
+
 QgsAbstractLabelingEngineRule *QgsLabelingEngineRuleRegistry::create( const QString &id ) const
 {
   auto it = mRules.find( id );

diff --git a/src/core/labeling/rules/qgslabelingengineruleregistry.h b/src/core/labeling/rules/qgslabelingengineruleregistry.h
@@ -61,6 +61,14 @@ class CORE_EXPORT QgsLabelingEngineRuleRegistry
      */
     QString displayType( const QString &id ) const;
 
+    /**
+     * Returns TRUE if the rule is with matching \a id is available for use within the current QGIS environment.
+     *
+     * Rules can return FALSE if required dependencies are not available, e.g. if a library version
+     * is too old for the rule.
+     */
+    bool isAvailable( const QString &id ) const;
+
     /**
      * Creates a new rule from the type with matching \a id.
      *

diff --git a/src/gui/labeling/qgslabelingengineruleswidget.cpp b/src/gui/labeling/qgslabelingengineruleswidget.cpp
@@ -41,7 +41,12 @@ Qt::ItemFlags QgsLabelingEngineRulesModel::flags( const QModelIndex &index ) con
   if ( !rule )
     return Qt::ItemFlags();
 
-  Qt::ItemFlags res = Qt::ItemIsEnabled | Qt::ItemIsSelectable | Qt::ItemIsEditable;
+  Qt::ItemFlags res = Qt::ItemIsSelectable;
+  if ( rule->isAvailable() )
+  {
+    res |= Qt::ItemIsEnabled | Qt::ItemIsEditable;
+  }
+
   if ( index.column() == 0 )
   {
     res |= Qt::ItemIsUserCheckable;
@@ -87,6 +92,9 @@ QVariant QgsLabelingEngineRulesModel::data( const QModelIndex &index, int role )
 
     case Qt::ToolTipRole:
     {
+      if ( !rule->isAvailable() )
+        return tr( "This rule is not available for use on this system." );
+
       return rule->description();
     }
 
@@ -265,6 +273,9 @@ void QgsLabelingEngineRulesWidget::createTypesMenu()
   QList< QAction * > actions;
   for ( const QString &id : ruleIds )
   {
+    if ( ! QgsApplication::labelingEngineRuleRegistry()->isAvailable( id ) )
+      continue;
+
     QAction *action = new QAction( QgsApplication::labelingEngineRuleRegistry()->create( id )->displayType() );
     connect( action, &QAction::triggered, this, [this, id ]
     {
@@ -309,10 +320,9 @@ void QgsLabelingEngineRulesWidget::editSelectedRule()
 void QgsLabelingEngineRulesWidget::editRule( const QModelIndex &index )
 {
   const QgsAbstractLabelingEngineRule *rule = mModel->ruleAtIndex( index );
-  if ( !rule )
+  if ( !rule || !rule->isAvailable() )
     return;
 
-
   // TODO -- move to a registry when there's a need
   QgsLabelingEngineRuleWidget *widget = nullptr;
   if ( rule->id() == "minimumDistanceLabelToFeature" )