ProSnippets Labeling

Language:              C#  
Subject:               Labeling  
Contributor:           ArcGIS Pro SDK Team <arcgisprosdk@esri.com>  
Organization:          esri, http://www.esri.com  
Date:                  10/22/2024  
ArcGIS Pro:            3.4  
Visual Studio:         2022  
.NET Target Framework: .Net 8  

Get the active map's labeling engine - Maplex or Standard labeling engine

//Note: call within QueuedTask.Run()

//Get the active map's definition - CIMMap.
var cimMap = MapView.Active.Map.GetDefinition();
//Get the labeling engine from the map definition
CIMGeneralPlacementProperties labelEngine = cimMap.GeneralPlacementProperties;

Change the active map's labeling engine from Standard to Maplex or vice versa

//Note: call within QueuedTask.Run()

//Get the active map's definition - CIMMap.
var cimMap = MapView.Active.Map.GetDefinition();
//Get the labeling engine from the map definition
var cimGeneralPlacement = cimMap.GeneralPlacementProperties;

if (cimGeneralPlacement is CIMMaplexGeneralPlacementProperties)
{
  //Current labeling engine is Maplex labeling engine
  //Create a new standard label engine properties
  var cimStandardPlacementProperties = new CIMStandardGeneralPlacementProperties();
  //Set the CIMMap's GeneralPlacementProperties to the new label engine
  cimMap.GeneralPlacementProperties = cimStandardPlacementProperties;
}
else
{
  //Current labeling engine is Standard labeling engine
  //Create a new Maplex label engine properties
  var cimMaplexGeneralPlacementProperties = new CIMMaplexGeneralPlacementProperties();
  //Set the CIMMap's GeneralPlacementProperties to the new label engine
  cimMap.GeneralPlacementProperties = cimMaplexGeneralPlacementProperties;
}
//Set the map's definition
MapView.Active.Map.SetDefinition(cimMap);

Apply text symbol to a feature layer

//Note: call within QueuedTask.Run()

//Get the layer's definition
var lyrDefn = featureLayer.GetDefinition() as CIMFeatureLayer;
//Get the label classes - we need the first one
var listLabelClasses = lyrDefn.LabelClasses.ToList();
var theLabelClass = listLabelClasses.FirstOrDefault();
//Set the label classes' symbol to the custom text symbol
//Refer to the ProSnippets-TextSymbols wiki page for help with creating custom text symbols.
//Example: var textSymbol = await CreateTextSymbolWithHaloAsync();
theLabelClass.TextSymbol.Symbol = textSymbol;
lyrDefn.LabelClasses = listLabelClasses.ToArray(); //Set the labelClasses back
featureLayer.SetDefinition(lyrDefn); //set the layer's definition
                                     //set the label's visiblity
featureLayer.SetLabelVisibility(true);

Enable labeling of a layer

//Note: call within QueuedTask.Run()

if (!featureLayer.IsLabelVisible)
  //set the label's visiblity
  featureLayer.SetLabelVisibility(true);

Modify the Placement/Position of labels - Point geometry

//Note: call within QueuedTask.Run()

//Get the layer's definition
var lyrDefn = featureLayer.GetDefinition() as CIMFeatureLayer;
//Get the label classes - we need the first one
var listLabelClasses = lyrDefn.LabelClasses.ToList();
var theLabelClass = listLabelClasses.FirstOrDefault();

//Modify label Placement 
//Check if the label engine is Maplex or standard.
CIMGeneralPlacementProperties labelEngine = 
   MapView.Active.Map.GetDefinition().GeneralPlacementProperties;
if (labelEngine is CIMStandardGeneralPlacementProperties) //Current labeling engine is Standard labeling engine               
  theLabelClass.StandardLabelPlacementProperties.PointPlacementMethod = 
           StandardPointPlacementMethod.OnTopPoint;
else    //Current labeling engine is Maplex labeling engine            
  theLabelClass.MaplexLabelPlacementProperties.PointPlacementMethod = 
          MaplexPointPlacementMethod.CenteredOnPoint;

lyrDefn.LabelClasses = listLabelClasses.ToArray(); //Set the labelClasses back
featureLayer.SetDefinition(lyrDefn); //set the layer's definition

Modify the Placement/Position of labels - Line geometry

//Note: call within QueuedTask.Run()

//Get the layer's definition
var lyrDefn = featureLayer.GetDefinition() as CIMFeatureLayer;
//Get the label classes - we need the first one
var listLabelClasses = lyrDefn.LabelClasses.ToList();
var theLabelClass = listLabelClasses.FirstOrDefault();
//Modify label Placement 
//Check if the label engine is Maplex or standard.
CIMGeneralPlacementProperties labelEngine = 
    MapView.Active.Map.GetDefinition().GeneralPlacementProperties;
if (labelEngine is CIMStandardGeneralPlacementProperties)
{
  //Current labeling engine is Standard labeling engine
  var lineLablePosition = new CIMStandardLineLabelPosition
  {
    Perpendicular = true,
    Parallel = false,
    ProduceCurvedLabels = false,
    Horizontal = false,
    OnTop = true
  };
  theLabelClass.StandardLabelPlacementProperties.LineLabelPosition = 
      lineLablePosition;
}
else //Current labeling engine is Maplex labeling engine
{
  theLabelClass.MaplexLabelPlacementProperties.LinePlacementMethod = 
                MaplexLinePlacementMethod.CenteredPerpendicularOnLine;
  theLabelClass.MaplexLabelPlacementProperties.LineFeatureType = 
                MaplexLineFeatureType.General;
}
//theLabelClass.MaplexLabelPlacementProperties.LinePlacementMethod = MaplexLinePlacementMethod.CenteredPerpendicularOnLine;
lyrDefn.LabelClasses = listLabelClasses.ToArray(); //Set the labelClasses back
featureLayer.SetDefinition(lyrDefn); //set the layer's definition

Modify the Placement/Position of labels - Polygon geometry

//Note: call within QueuedTask.Run()

//Get the layer's definition
var lyrDefn = featureLayer.GetDefinition() as CIMFeatureLayer;
//Get the label classes - we need the first one
var listLabelClasses = lyrDefn.LabelClasses.ToList();
var theLabelClass = listLabelClasses.FirstOrDefault();
//Modify label Placement 
//Check if the label engine is Maplex or standard.
CIMGeneralPlacementProperties labelEngine = MapView.Active.Map.GetDefinition().GeneralPlacementProperties;
if (labelEngine is CIMStandardGeneralPlacementProperties)
{
  //Current labeling engine is Standard Labeling engine
  theLabelClass.StandardLabelPlacementProperties.PolygonPlacementMethod = 
           StandardPolygonPlacementMethod.AlwaysHorizontal;
  theLabelClass.StandardLabelPlacementProperties.PlaceOnlyInsidePolygon = true;
}
else
{
  //Current labeling engine is Maplex labeling engine
  theLabelClass.MaplexLabelPlacementProperties.PolygonFeatureType = 
                           MaplexPolygonFeatureType.LandParcel;
  theLabelClass.MaplexLabelPlacementProperties.AvoidPolygonHoles = true;
  theLabelClass.MaplexLabelPlacementProperties.PolygonPlacementMethod = 
                      MaplexPolygonPlacementMethod.HorizontalInPolygon;
  theLabelClass.MaplexLabelPlacementProperties.CanPlaceLabelOutsidePolygon = true;
}

lyrDefn.LabelClasses = listLabelClasses.ToArray(); //Set the labelClasses back
featureLayer.SetDefinition(lyrDefn); //set the layer's definition
                                     //set the label's visiblity
featureLayer.SetLabelVisibility(true);

Modify Orientation of a label using the MaplexEngine - Points and Polygon geometry

//Note: call within QueuedTask.Run()

//Get the layer's definition
var lyrDefn = featureLayer.GetDefinition() as CIMFeatureLayer;
//Get the label classes - we need the first one
var listLabelClasses = lyrDefn.LabelClasses.ToList();
var theLabelClass = listLabelClasses.FirstOrDefault();
//Modify label Orientation                 
theLabelClass.MaplexLabelPlacementProperties.GraticuleAlignment = true;
theLabelClass.MaplexLabelPlacementProperties.GraticuleAlignmentType = MaplexGraticuleAlignmentType.Curved;

lyrDefn.LabelClasses = listLabelClasses.ToArray(); //Set the labelClasses back
featureLayer.SetDefinition(lyrDefn); //set the layer's definition

Modify Orientation of a label using the MaplexEngine - Line geometry

//Note: call within QueuedTask.Run()

//Get the layer's definition
var lyrDefn = featureLayer.GetDefinition() as CIMFeatureLayer;
//Get the label classes - we need the first one
var listLabelClasses = lyrDefn.LabelClasses.ToList();
var theLabelClass = listLabelClasses.FirstOrDefault();
//Modify label Orientation
theLabelClass.MaplexLabelPlacementProperties.AlignLabelToLineDirection = true;

lyrDefn.LabelClasses = listLabelClasses.ToArray(); //Set the labelClasses back
featureLayer.SetDefinition(lyrDefn); //set the layer's definition

Modify label Rotation - Point geometry

//Note: call within QueuedTask.Run()

//Get the layer's definition
var lyrDefn = featureLayer.GetDefinition() as CIMFeatureLayer;
//Get the label classes - we need the first one
var listLabelClasses = lyrDefn.LabelClasses.ToList();
var theLabelClass = listLabelClasses.FirstOrDefault();
//Modify label Rotation
CIMMaplexRotationProperties rotationProperties = new CIMMaplexRotationProperties
{
  Enable = true, //Enable rotation
  RotationField = "ELEVATION", //Field that is used to define rotation angle
  AdditionalAngle = 15, //Additional rotation 
  RotationType = MaplexLabelRotationType.Arithmetic,
  AlignmentType = MaplexRotationAlignmentType.Perpendicular,
  AlignLabelToAngle = true
};
theLabelClass.MaplexLabelPlacementProperties.RotationProperties = rotationProperties;
lyrDefn.LabelClasses = listLabelClasses.ToArray(); //Set the labelClasses back
featureLayer.SetDefinition(lyrDefn); //set the layer's definition

Spread labels across Polygon geometry

//Note: call within QueuedTask.Run()

//Get the layer's definition
var lyrDefn = featureLayer.GetDefinition() as CIMFeatureLayer;
//Get the label classes - we need the first one
var listLabelClasses = lyrDefn.LabelClasses.ToList();
var theLabelClass = listLabelClasses.FirstOrDefault();
//Spread Labels (words and characters to fill feature)
// Spread words to fill feature
theLabelClass.MaplexLabelPlacementProperties.SpreadWords = true;
//Spread Characters to a fixed limit of 50%
theLabelClass.MaplexLabelPlacementProperties.SpreadCharacters = true;
theLabelClass.MaplexLabelPlacementProperties.MaximumCharacterSpacing = 50.0;
lyrDefn.LabelClasses = listLabelClasses.ToArray(); //Set the labelClasses back
featureLayer.SetDefinition(lyrDefn); //set the layer's definition

Modify label's Leader Line Anchor point properties - Polygon geometry

//Note: call within QueuedTask.Run()

//Get the layer's definition
var lyrDefn = featureLayer.GetDefinition() as CIMFeatureLayer;
//Get the label classes - we need the first one
var listLabelClasses = lyrDefn.LabelClasses.ToList();
var theLabelClass = listLabelClasses.FirstOrDefault();
//If TextSymbol is a callout the leader line anachor point can be modified
theLabelClass.MaplexLabelPlacementProperties.PolygonAnchorPointType = MaplexAnchorPointType.Perimeter;
lyrDefn.LabelClasses = listLabelClasses.ToArray(); //Set the labelClasses back
featureLayer.SetDefinition(lyrDefn); //set the layer's definition