[FEATURE][layouts] Data defined table source for attribute table items

When an attribute table is set to a "Layer features" source, this
allows the underlying vector layer from which to source features
to be data defined.

(All existing table attributes (column settings) are left intact,
so setting a data defined table to a layer with different fields
will result in empty columns in the table.)

Sponsored by Kartoza/Inasafe

python/core/layout/qgslayoutitemattributetable.sip.in

@@ -295,6 +295,9 @@ be replaced by a line break.
     virtual void finalizeRestoreFromXml();
 
 
+    virtual void refreshDataDefinedProperty( const QgsLayoutObject::DataDefinedProperty property = QgsLayoutObject::AllProperties );
+
+
   protected:
 
     virtual bool writePropertiesToElement( QDomElement &elem, QDomDocument &doc, const QgsReadWriteContext &context ) const;

python/core/layout/qgslayoutobject.sip.in

@@ -71,6 +71,8 @@ A base class for objects which belong to a layout.
       ScalebarFillColor2,
       ScalebarLineColor,
       ScalebarLineWidth,
+      //table
+      AttributeTableSourceLayer,
     };
 
     enum PropertyValueType

src/app/layout/qgslayoutattributetablewidget.cpp

@@ -131,8 +131,12 @@ QgsLayoutAttributeTableWidget::QgsLayoutAttributeTableWidget( QgsLayoutFrame *fr
     {
       connect( atlas, &QgsLayoutAtlas::toggled, this, &QgsLayoutAttributeTableWidget::atlasToggled );
     }
+
+    mLayerSourceDDBtn->registerExpressionContextGenerator( mTable );
   }
 
+  registerDataDefinedButton( mLayerSourceDDBtn, QgsLayoutObject::AttributeTableSourceLayer );
+
   //embed widget for general options
   if ( mFrame )
   {
@@ -925,6 +929,7 @@ void QgsLayoutAttributeTableWidget::toggleSourceControls()
     case QgsLayoutItemAttributeTable::LayerAttributes:
       mLayerComboBox->setEnabled( true );
       mLayerComboBox->setVisible( true );
+      mLayerSourceDDBtn->setVisible( true );
       mLayerLabel->setVisible( true );
       mRelationsComboBox->setEnabled( false );
       mRelationsComboBox->setVisible( false );
@@ -938,6 +943,7 @@ void QgsLayoutAttributeTableWidget::toggleSourceControls()
     case QgsLayoutItemAttributeTable::AtlasFeature:
       mLayerComboBox->setEnabled( false );
       mLayerComboBox->setVisible( false );
+      mLayerSourceDDBtn->setVisible( false );
       mLayerLabel->setVisible( false );
       mRelationsComboBox->setEnabled( false );
       mRelationsComboBox->setVisible( false );
@@ -952,6 +958,7 @@ void QgsLayoutAttributeTableWidget::toggleSourceControls()
       mLayerComboBox->setEnabled( false );
       mLayerComboBox->setVisible( false );
       mLayerLabel->setVisible( false );
+      mLayerSourceDDBtn->setVisible( false );
       mRelationsComboBox->setEnabled( true );
       mRelationsComboBox->setVisible( true );
       mRelationLabel->setVisible( true );

src/core/layout/qgslayoutitemattributetable.cpp

@@ -552,6 +552,28 @@ void QgsLayoutItemAttributeTable::finalizeRestoreFromXml()
   }
 }
 
+void QgsLayoutItemAttributeTable::refreshDataDefinedProperty( const QgsLayoutObject::DataDefinedProperty property )
+{
+  QgsExpressionContext context = createExpressionContext();
+
+  if ( mSource == QgsLayoutItemAttributeTable::LayerAttributes &&
+       ( property == QgsLayoutObject::AttributeTableSourceLayer || property == QgsLayoutObject::AllProperties ) )
+  {
+    mDataDefinedVectorLayer = nullptr;
+
+    QString currentLayerIdentifier;
+    if ( QgsVectorLayer *currentLayer = mVectorLayer.get() )
+      currentLayerIdentifier = currentLayer->id();
+
+    const QString layerIdentifier = mDataDefinedProperties.valueAsString( QgsLayoutObject::AttributeTableSourceLayer, context, currentLayerIdentifier );
+    QgsVectorLayer *ddLayer = qobject_cast< QgsVectorLayer * >( QgsLayoutUtils::mapLayerFromString( layerIdentifier, mLayout->project() ) );
+    if ( ddLayer )
+      mDataDefinedVectorLayer = ddLayer;
+  }
+
+  QgsLayoutMultiFrame::refreshDataDefinedProperty( property );
+}
+
 QVariant QgsLayoutItemAttributeTable::replaceWrapChar( const QVariant &variant ) const
 {
   //avoid converting variants to string if not required (try to maintain original type for sorting)
@@ -570,7 +592,12 @@ QgsVectorLayer *QgsLayoutItemAttributeTable::sourceLayer() const
     case QgsLayoutItemAttributeTable::AtlasFeature:
       return mLayout->reportContext().layer();
     case QgsLayoutItemAttributeTable::LayerAttributes:
-      return mVectorLayer.get();
+    {
+      if ( mDataDefinedVectorLayer )
+        return mDataDefinedVectorLayer;
+      else
+        return mVectorLayer.get();
+    }
     case QgsLayoutItemAttributeTable::RelationChildren:
     {
       QgsRelation relation = mLayout->project()->relationManager()->relation( mRelationId );

src/core/layout/qgslayoutitemattributetable.h

@@ -292,6 +292,8 @@ class CORE_EXPORT QgsLayoutItemAttributeTable: public QgsLayoutTable
     QgsExpressionContext createExpressionContext() const override;
     void finalizeRestoreFromXml() override;
 
+    void refreshDataDefinedProperty( const QgsLayoutObject::DataDefinedProperty property = QgsLayoutObject::AllProperties ) override;
+
   protected:
 
     bool writePropertiesToElement( QDomElement &elem, QDomDocument &doc, const QgsReadWriteContext &context ) const override;
@@ -303,6 +305,10 @@ class CORE_EXPORT QgsLayoutItemAttributeTable: public QgsLayoutTable
     ContentSource mSource = LayerAttributes;
     //! Associated vector layer
     QgsVectorLayerRef mVectorLayer;
+
+    //! Data defined vector layer - only
+    QPointer< QgsVectorLayer > mDataDefinedVectorLayer;
+
     //! Relation id, if in relation children mode
     QString mRelationId;
 

src/core/layout/qgslayoutobject.cpp

@@ -76,6 +76,7 @@ void QgsLayoutObject::initPropertyDefinitions()
     { QgsLayoutObject::ScalebarFillColor2, QgsPropertyDefinition( "dataDefinedScalebarFill2", QObject::tr( "Secondary fill color" ), QgsPropertyDefinition::ColorWithAlpha ) },
     { QgsLayoutObject::ScalebarLineColor, QgsPropertyDefinition( "dataDefinedScalebarLineColor", QObject::tr( "Line color" ), QgsPropertyDefinition::ColorWithAlpha ) },
     { QgsLayoutObject::ScalebarLineWidth, QgsPropertyDefinition( "dataDefinedScalebarLineWidth", QObject::tr( "Line width" ), QgsPropertyDefinition::StrokeWidth ) },
+    { QgsLayoutObject::AttributeTableSourceLayer, QgsPropertyDefinition( "dataDefinedAttributeTableSourceLayer", QObject::tr( "Table source layer" ), QgsPropertyDefinition::String ) },
   };
 }
 

src/core/layout/qgslayoutobject.h

@@ -92,7 +92,9 @@ class CORE_EXPORT QgsLayoutObject: public QObject, public QgsExpressionContextGe
       ScalebarFillColor, //!< Scalebar fill color
       ScalebarFillColor2, //!< Scalebar secondary fill color
       ScalebarLineColor, //!< Scalebar line color
-      ScalebarLineWidth, //!< Scalebar line width
+      ScalebarLineWidth, //!< Scalebar line width,
+      //table item
+      AttributeTableSourceLayer, //!< Attribute table source layer
     };
 
     /**

src/ui/layout/qgslayoutattributetablewidgetbase.ui

@@ -55,8 +55,8 @@
        <rect>
         <x>0</x>
         <y>0</y>
-        <width>689</width>
-        <height>2574</height>
+        <width>394</width>
+        <height>1487</height>
        </rect>
       </property>
       <layout class="QVBoxLayout" name="mainLayout">
@@ -85,50 +85,61 @@
           <item row="0" column="1">
            <widget class="QComboBox" name="mSourceComboBox"/>
           </item>
-          <item row="1" column="0">
-           <widget class="QLabel" name="mLayerLabel">
-            <property name="text">
-             <string>Layer</string>
-            </property>
-            <property name="wordWrap">
-             <bool>true</bool>
-            </property>
-           </widget>
-          </item>
-          <item row="1" column="1">
-           <widget class="QgsMapLayerComboBox" name="mLayerComboBox">
-            <property name="sizePolicy">
-             <sizepolicy hsizetype="Expanding" vsizetype="Fixed">
-              <horstretch>0</horstretch>
-              <verstretch>0</verstretch>
-             </sizepolicy>
-            </property>
-           </widget>
-          </item>
-          <item row="2" column="0">
+          <item row="5" column="0">
            <widget class="QLabel" name="mRelationLabel">
             <property name="text">
              <string>Relation</string>
             </property>
            </widget>
           </item>
-          <item row="2" column="1">
+          <item row="5" column="1">
            <widget class="QComboBox" name="mRelationsComboBox"/>
           </item>
-          <item row="3" column="0" colspan="2">
+          <item row="6" column="0" colspan="2">
            <widget class="QPushButton" name="mRefreshPushButton">
             <property name="text">
              <string>Refresh table data</string>
             </property>
            </widget>
           </item>
-          <item row="4" column="0" colspan="2">
+          <item row="7" column="0" colspan="2">
            <widget class="QPushButton" name="mAttributesPushButton">
             <property name="text">
              <string>Attributes...</string>
             </property>
            </widget>
           </item>
+          <item row="1" column="0">
+           <widget class="QLabel" name="mLayerLabel">
+            <property name="text">
+             <string>Layer</string>
+            </property>
+            <property name="wordWrap">
+             <bool>true</bool>
+            </property>
+           </widget>
+          </item>
+          <item row="1" column="1">
+           <layout class="QHBoxLayout" name="horizontalLayout_6">
+            <item>
+             <widget class="QgsMapLayerComboBox" name="mLayerComboBox">
+              <property name="sizePolicy">
+               <sizepolicy hsizetype="Expanding" vsizetype="Fixed">
+                <horstretch>0</horstretch>
+                <verstretch>0</verstretch>
+               </sizepolicy>
+              </property>
+             </widget>
+            </item>
+            <item>
+             <widget class="QgsPropertyOverrideButton" name="mLayerSourceDDBtn">
+              <property name="text">
+               <string>…</string>
+              </property>
+             </widget>
+            </item>
+           </layout>
+          </item>
          </layout>
         </widget>
        </item>
@@ -832,12 +843,18 @@
    <extends>QComboBox</extends>
    <header>qgslayoutitemcombobox.h</header>
   </customwidget>
+  <customwidget>
+   <class>QgsPropertyOverrideButton</class>
+   <extends>QToolButton</extends>
+   <header>qgspropertyoverridebutton.h</header>
+  </customwidget>
  </customwidgets>
  <tabstops>
   <tabstop>scrollArea</tabstop>
   <tabstop>groupBox</tabstop>
   <tabstop>mSourceComboBox</tabstop>
   <tabstop>mLayerComboBox</tabstop>
+  <tabstop>mLayerSourceDDBtn</tabstop>
   <tabstop>mRelationsComboBox</tabstop>
   <tabstop>mRefreshPushButton</tabstop>
   <tabstop>mAttributesPushButton</tabstop>
@@ -905,6 +922,8 @@
   <include location="../../../images/images.qrc"/>
   <include location="../../../images/images.qrc"/>
   <include location="../../../images/images.qrc"/>
+  <include location="../../../images/images.qrc"/>
+  <include location="../../../images/images.qrc"/>
  </resources>
  <connections/>
 </ui>

tests/src/core/testqgslayouttable.cpp

@@ -70,6 +70,7 @@ class TestQgsLayoutTable : public QObject
     void autoWrap(); //test auto word wrap
     void cellStyles(); //test cell styles
     void cellStylesRender(); //test rendering cell styles
+    void dataDefinedSource();
 
   private:
     QgsVectorLayer *mVectorLayer = nullptr;
@@ -1323,5 +1324,69 @@ void TestQgsLayoutTable::cellStylesRender()
   QVERIFY( checker.testLayout( mReport, 0 ) );
 }
 
+void TestQgsLayoutTable::dataDefinedSource()
+{
+  // add a couple of layers
+  QgsVectorLayer *layer1 = new QgsVectorLayer( QStringLiteral( "Point?field=col1:integer&field=col2:integer&field=col3:integer" ), QStringLiteral( "l1" ), QStringLiteral( "memory" ) );
+  QVERIFY( layer1->isValid() );
+  QgsFeature f( layer1->fields() );
+  f.setAttributes( QgsAttributes() << 1 << 2 << 3 );
+  layer1->dataProvider()->addFeature( f );
+
+  // different field order
+  QgsVectorLayer *layer2 = new QgsVectorLayer( QStringLiteral( "Point?field=col1:integer&field=col3:integer&field=col2:integer" ), QStringLiteral( "l2" ), QStringLiteral( "memory" ) );
+  QVERIFY( layer2->isValid() );
+  QgsFeature f2( layer2->fields() );
+  f2.setAttributes( QgsAttributes() << 11 << 13 << 12 );
+  layer2->dataProvider()->addFeature( f2 );
+
+  // missing fields
+  QgsVectorLayer *layer3 = new QgsVectorLayer( QStringLiteral( "Point?field=col1:integer&field=col3:integer" ), QStringLiteral( "l3" ), QStringLiteral( "memory" ) );
+  QVERIFY( layer3->isValid() );
+  QgsFeature f3( layer3->fields() );
+  f3.setAttributes( QgsAttributes() << 21 << 23 );
+  layer3->dataProvider()->addFeature( f3 );
+
+  QgsProject p;
+  p.addMapLayer( layer1 );
+  p.addMapLayer( layer2 );
+  p.addMapLayer( layer3 );
+
+  QgsLayout l( &p );
+  l.initializeDefaults();
+  QgsLayoutItemAttributeTable *table = new QgsLayoutItemAttributeTable( &l );
+  table->setSource( QgsLayoutItemAttributeTable::LayerAttributes );
+  table->setVectorLayer( layer1 );
+  table->setMaximumNumberOfFeatures( 50 );
+  QCOMPARE( table->contents().length(), 1 );
+  QCOMPARE( table->contents().at( 0 ), QVector< QVariant >() << 1 << 2 << 3 );
+
+  // data defined table name, by layer id
+  table->dataDefinedProperties().setProperty( QgsLayoutObject::AttributeTableSourceLayer, layer1->id() );
+  table->refresh();
+  QCOMPARE( table->contents().length(), 1 );
+  QCOMPARE( table->contents().at( 0 ), QVector< QVariant >() << 1 << 2 << 3 );
+
+  // by layer name
+  table->dataDefinedProperties().setProperty( QgsLayoutObject::AttributeTableSourceLayer, QStringLiteral( "l2" ) );
+  table->refresh();
+  QCOMPARE( table->contents().length(), 1 );
+  QCOMPARE( table->contents().at( 0 ), QVector< QVariant >() << 11 << 12 << 13 );
+
+  // by layer name (case insensitive)
+  table->dataDefinedProperties().setProperty( QgsLayoutObject::AttributeTableSourceLayer, QStringLiteral( "L3" ) );
+  table->refresh();
+  QCOMPARE( table->contents().length(), 1 );
+  QCOMPARE( table->contents().at( 0 ), QVector< QVariant >() << 21 << QVariant() << 23 );
+
+  // delete current data defined layer match
+  p.removeMapLayer( layer3->id() );
+  QApplication::sendPostedEvents( nullptr, QEvent::DeferredDelete );
+  // expect table to return to preset layer
+  table->refreshAttributes();
+  QCOMPARE( table->contents().length(), 1 );
+  QCOMPARE( table->contents().at( 0 ), QVector< QVariant >() << 1 << 2 << 3 );
+}
+
 QGSTEST_MAIN( TestQgsLayoutTable )
 #include "testqgslayouttable.moc"