Merge pull request #4825

Various new expression functions and possibilities
qgis · Jul 8, 2017 · ada9ce4 · ada9ce4
2 parents 6b6a52b + 89a06f6
commit ada9ce4
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Showing 26 changed files with 402 additions and 75 deletions.
diff --git a/python/core/expression/qgsexpressionfunction.sip b/python/core/expression/qgsexpressionfunction.sip
@@ -249,6 +249,11 @@ The help text for the function.
  :rtype: QVariant
 %End
 
+    virtual QVariant run( QgsExpressionNode::NodeList *args, const QgsExpressionContext *context, QgsExpression *parent );
+%Docstring
+ :rtype: QVariant
+%End
+
     bool operator==( const QgsExpressionFunction &other ) const;
 
     virtual bool handlesNull() const;

diff --git a/python/core/geometry/qgscompoundcurve.sip b/python/core/geometry/qgscompoundcurve.sip
@@ -77,7 +77,7 @@ class QgsCompoundCurve: QgsCurve
 
     void addCurve( QgsCurve *c /Transfer/ );
 %Docstring
- Adds a curve to the geometr (takes ownership)
+ Adds a curve to the geometry (takes ownership)
 %End
 
     void removeCurve( int i );

diff --git a/python/core/qgsexpressioncontext.sip b/python/core/qgsexpressioncontext.sip
@@ -809,6 +809,15 @@ class QgsExpressionContextUtils
  :rtype: QgsExpressionContextScope
 %End
 
+    static QgsExpressionContextScope *mapToolCaptureScope( const QList<QgsPointLocator::Match> &matches ) /Factory/;
+%Docstring
+ Sets the expression context variables which are available for expressions triggered by
+ a map tool capture like add feature.
+
+.. versionadded:: 3.0
+ :rtype: QgsExpressionContextScope
+%End
+
     static QgsExpressionContextScope *updateSymbolScope( const QgsSymbol *symbol, QgsExpressionContextScope *symbolScope = 0 );
 %Docstring
  Updates a symbol scope related to a QgsSymbol to an expression context.

diff --git a/python/gui/qgsmaptoolcapture.sip b/python/gui/qgsmaptoolcapture.sip
@@ -42,6 +42,14 @@ Adds a whole curve (e.g. circularstring) to the captured geometry. Curve must be
  :rtype: QgsCompoundCurve
 %End
 
+    QList<QgsPointLocator::Match> snappingMatches() const;
+%Docstring
+ Return a list of matches for each point on the captureCurve.
+
+.. versionadded:: 3.0
+ :rtype: list of QgsPointLocator.Match
+%End
+
     virtual void cadCanvasMoveEvent( QgsMapMouseEvent *e );
 
     virtual void keyPressEvent( QKeyEvent *e );

diff --git a/resources/function_help/json/array_first b/resources/function_help/json/array_first
@@ -0,0 +1,7 @@
+{
+  "name": "array_first",
+  "type": "function",
+  "description": "Returns the first value of an array.",
+  "arguments": [ {"arg":"array","description":"an array"} ],
+  "examples": [ { "expression":"array_first(array('a','b','c'))", "returns":"'a'"}]
+}
diff --git a/resources/function_help/json/array_last b/resources/function_help/json/array_last
@@ -0,0 +1,7 @@
+{
+  "name": "array_last",
+  "type": "function",
+  "description": "Returns the last value of an array.",
+  "arguments": [ {"arg":"array","description":"an array"} ],
+  "examples": [ { "expression":"array_last(array('a','b','c'))", "returns":"'c'"}]
+}
diff --git a/resources/function_help/json/get_feature_by_id b/resources/function_help/json/get_feature_by_id
@@ -0,0 +1,8 @@
+{
+  "name": "get_feature_by_id",
+  "type": "function",
+  "description": "Returns the feature with an id on a layer.",
+  "arguments": [ {"arg":"layer","description":"layer, layer name or layer id"},
+                 {"arg":"feature_id","description":"the id of the feature which should be returned"}],
+  "examples": [ { "expression":"get_feature('streets', 1)", "returns":"the feature with the id 1 on the layer \"streets\""}]
+}
diff --git a/resources/function_help/json/with_variable b/resources/function_help/json/with_variable
@@ -0,0 +1,11 @@
+{
+  "name": "with_variable",
+  "type": "function",
+  "description": "This function sets a variable for any expression code that will be provided as 3rd argument. This is only useful for complicated expressions, where the same calculated value needs to be used in different places.",
+  "arguments": [
+                 {"arg":"name","description":"the name of the variable to set"},
+                 {"arg":"value","description":"the value to set"},
+                 {"arg":"node","description":"the expression for which the variable will be available"}
+               ],
+  "examples": [ { "expression":"with_variable('my_sum', 1 + 2 + 3, @my_sum * 2 + @my_sum * 5)", "returns":"42"}]
+}
diff --git a/src/app/qgsattributetypedialog.cpp b/src/app/qgsattributetypedialog.cpp
@@ -71,6 +71,8 @@ QgsAttributeTypeDialog::QgsAttributeTypeDialog( QgsVectorLayer *vl, int fieldIdx
     isFieldEditableCheckBox->setEnabled( false );
   }
 
+  mExpressionWidget->registerExpressionContextGenerator( this );
+
   connect( mExpressionWidget, &QgsExpressionLineEdit::expressionChanged, this, &QgsAttributeTypeDialog::defaultExpressionChanged );
   connect( mUniqueCheckBox, &QCheckBox::toggled, this, [ = ]( bool checked )
   {
@@ -293,6 +295,18 @@ void QgsAttributeTypeDialog::setDefaultValueExpression( const QString &expressio
   mExpressionWidget->setExpression( expression );
 }
 
+QgsExpressionContext QgsAttributeTypeDialog::createExpressionContext() const
+{
+  QgsExpressionContext context;
+  context
+      << QgsExpressionContextUtils::globalScope()
+      << QgsExpressionContextUtils::projectScope( QgsProject::instance() )
+      << QgsExpressionContextUtils::layerScope( mLayer )
+      << QgsExpressionContextUtils::mapToolCaptureScope( QList<QgsPointLocator::Match>() );
+
+  return context;
+}
+
 QString QgsAttributeTypeDialog::constraintExpression() const
 {
   return constraintExpressionWidget->asExpression();

diff --git a/src/app/qgsattributetypedialog.h b/src/app/qgsattributetypedialog.h
@@ -26,7 +26,7 @@
 
 class QDialog;
 
-class APP_EXPORT QgsAttributeTypeDialog: public QDialog, private Ui::QgsAttributeTypeDialog
+class APP_EXPORT QgsAttributeTypeDialog: public QDialog, private Ui::QgsAttributeTypeDialog, QgsExpressionContextGenerator
 {
     Q_OBJECT
 
@@ -163,6 +163,8 @@ class APP_EXPORT QgsAttributeTypeDialog: public QDialog, private Ui::QgsAttribut
      */
     void setDefaultValueExpression( const QString &expression );
 
+    QgsExpressionContext createExpressionContext() const override;
+
   private slots:
 
     /**

diff --git a/src/app/qgsfeatureaction.cpp b/src/app/qgsfeatureaction.cpp
@@ -161,7 +161,7 @@ bool QgsFeatureAction::editFeature( bool showModal )
   return true;
 }
 
-bool QgsFeatureAction::addFeature( const QgsAttributeMap &defaultAttributes, bool showModal )
+bool QgsFeatureAction::addFeature( const QgsAttributeMap &defaultAttributes, bool showModal, QgsExpressionContextScope *scope SIP_TRANSFER )
 {
   if ( !mLayer || !mLayer->isEditable() )
     return false;
@@ -188,6 +188,9 @@ bool QgsFeatureAction::addFeature( const QgsAttributeMap &defaultAttributes, boo
   // create new feature template - this will initialize the attributes to valid values, handling default
   // values and field constraints
   QgsExpressionContext context = mLayer->createExpressionContext();
+  if ( scope )
+    context.appendScope( scope );
+
   QgsFeature newFeature = QgsVectorLayerUtils::createFeature( mLayer, mFeature->geometry(), initialAttributeValues,
                           &context );
   *mFeature = newFeature;

diff --git a/src/app/qgsfeatureaction.h b/src/app/qgsfeatureaction.h
@@ -29,6 +29,7 @@ class QgsIdentifyResultsDialog;
 class QgsVectorLayer;
 class QgsHighlight;
 class QgsAttributeDialog;
+class QgsExpressionContextScope;
 
 class APP_EXPORT QgsFeatureAction : public QAction
 {
@@ -51,7 +52,7 @@ class APP_EXPORT QgsFeatureAction : public QAction
      *
      * \returns true if feature was added if showModal is true. If showModal is false, returns true in every case
      */
-    bool addFeature( const QgsAttributeMap &defaultAttributes = QgsAttributeMap(), bool showModal = true );
+    bool addFeature( const QgsAttributeMap &defaultAttributes = QgsAttributeMap(), bool showModal = true, QgsExpressionContextScope *scope = nullptr );
 
   private slots:
     void onFeatureSaved( const QgsFeature &feature );

diff --git a/src/app/qgsmaptooladdfeature.cpp b/src/app/qgsmaptooladdfeature.cpp
@@ -48,8 +48,9 @@ QgsMapToolAddFeature::~QgsMapToolAddFeature()
 
 bool QgsMapToolAddFeature::addFeature( QgsVectorLayer *vlayer, QgsFeature *f, bool showModal )
 {
+  QgsExpressionContextScope *scope = QgsExpressionContextUtils::mapToolCaptureScope( snappingMatches() );
   QgsFeatureAction *action = new QgsFeatureAction( tr( "add feature" ), *f, vlayer, QString(), -1, this );
-  bool res = action->addFeature( QgsAttributeMap(), showModal );
+  bool res = action->addFeature( QgsAttributeMap(), showModal, scope );
   if ( showModal )
     delete action;
   return res;
@@ -250,6 +251,7 @@ void QgsMapToolAddFeature::cadCanvasReleaseEvent( QgsMapMouseEvent *e )
       bool hasCurvedSegments = captureCurve()->hasCurvedSegments();
       bool providerSupportsCurvedSegments = vlayer->dataProvider()->capabilities() & QgsVectorDataProvider::CircularGeometries;
 
+      QList<QgsPointLocator::Match> snappingMatchesList;
       QgsCurve *curveToAdd = nullptr;
       if ( hasCurvedSegments && providerSupportsCurvedSegments )
       {
@@ -258,13 +260,13 @@ void QgsMapToolAddFeature::cadCanvasReleaseEvent( QgsMapMouseEvent *e )
       else
       {
         curveToAdd = captureCurve()->curveToLine();
+        snappingMatchesList = snappingMatches();
       }
 
       if ( mode() == CaptureLine )
       {
-        QgsGeometry *g = new QgsGeometry( curveToAdd );
-        f->setGeometry( *g );
-        delete g;
+        QgsGeometry g( curveToAdd );
+        f->setGeometry( g );
       }
       else
       {
@@ -278,9 +280,8 @@ void QgsMapToolAddFeature::cadCanvasReleaseEvent( QgsMapMouseEvent *e )
           poly = new QgsPolygonV2();
         }
         poly->setExteriorRing( curveToAdd );
-        QgsGeometry *g = new QgsGeometry( poly );
-        f->setGeometry( *g );
-        delete g;
+        QgsGeometry g( poly );
+        f->setGeometry( g );
 
         QgsGeometry featGeom = f->geometry();
         int avoidIntersectionsReturn = featGeom.avoidIntersections( QgsProject::instance()->avoidIntersectionsLayers() );

diff --git a/src/app/qgsmaptooladdfeature.h b/src/app/qgsmaptooladdfeature.h
@@ -44,7 +44,6 @@ class APP_EXPORT QgsMapToolAddFeature : public QgsMapToolCapture
     void setCheckGeometryType( bool checkGeometryType );
 
   private:
-    QVariant snappingMatchesAsVariable() const;
 
     /** Check if CaptureMode matches layer type. Default is true.
      * \since QGIS 2.12 */

diff --git a/src/core/expression/qgsexpression.cpp b/src/core/expression/qgsexpression.cpp
@@ -673,6 +673,19 @@ void QgsExpression::initVariableHelp()
   sVariableHelpTexts.insert( QStringLiteral( "grid_number" ), QCoreApplication::translate( "variable_help", "Current grid annotation value." ) );
   sVariableHelpTexts.insert( QStringLiteral( "grid_axis" ), QCoreApplication::translate( "variable_help", "Current grid annotation axis (e.g., 'x' for longitude, 'y' for latitude)." ) );
 
+  // map tool capture variables
+  sVariableHelpTexts.insert( QStringLiteral( "snapping_results" ), QCoreApplication::translate( "variable_help",
+                             "<p>An array with an item for each snapped point.</p>"
+                             "<p>Each item is a map with the following keys:</p>"
+                             "<dl>"
+                             "<dt>valid</dt><dd>Boolean that indicates if the snapping result is valid</dd>"
+                             "<dt>layer</dt><dd>The layer on which the snapped feature is</dd>"
+                             "<dt>feature_id</dt><dd>The feature id of the snapped feature</dd>"
+                             "<dt>vertex_index</dt><dd>The index of the snapped vertex</dd>"
+                             "<dt>distance</dt><dd>The distance between the mouse cursor and the snapped point at the time of snapping</dd>"
+                             "</dl>" ) );
+
+
   //symbol variables
   sVariableHelpTexts.insert( QStringLiteral( "geometry_part_count" ), QCoreApplication::translate( "variable_help", "Number of parts in rendered feature's geometry." ) );
   sVariableHelpTexts.insert( QStringLiteral( "geometry_part_num" ), QCoreApplication::translate( "variable_help", "Current geometry part number for feature being rendered." ) );