ArcGIS Pro 3.3 API Reference Guide
ArcGIS.Core.CIM Namespace / CIMLabelClass Class / MaplexLabelPlacementProperties Property
Example

In This Topic
    MaplexLabelPlacementProperties Property
    In This Topic
    Gets or sets the Maplex placement properties which are used when the map uses the Maplex label engine.
    Syntax
    public CIMMaplexLabelPlacementProperties MaplexLabelPlacementProperties {get; set;}
    Public Property MaplexLabelPlacementProperties As CIMMaplexLabelPlacementProperties
    Example
    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 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
    Requirements

    Target Platforms: Windows 11, Windows 10

    ArcGIS Pro version: 3 or higher.
    See Also