<CategoryAttribute("Interactive Mode")>
<DescriptionAttribute("Occurs on interactive mode user rectangle operations.")>
Public Event InteractiveUserRectangle As EventHandler(Of RasterViewerRectangleEventArgs)

Dim instance As RasterImageViewer
Dim handler As EventHandler(Of RasterViewerRectangleEventArgs)
 
AddHandler instance.InteractiveUserRectangle, handler

[CategoryAttribute("Interactive Mode")]
[DescriptionAttribute("Occurs on interactive mode user rectangle operations.")]
public event EventHandler<RasterViewerRectangleEventArgs> InteractiveUserRectangle

[CategoryAttribute("Interactive Mode")]
[DescriptionAttribute("Occurs on interactive mode user rectangle operations.")]
public:
event EventHandler<RasterViewerRectangleEventArgs^>^ InteractiveUserRectangle

Public Sub InteractiveUserRectangleExample(ByVal viewer As RasterImageViewer)
   ' Set the interactive mode of the viewer to user-defined rectangle
   viewer.InteractiveMode = RasterViewerInteractiveMode.UserRectangle
   ' Subscribe to the InteractiveUserRectangle event to know when the user has finished drawing a new rectangle
   AddHandler viewer.InteractiveUserRectangle, AddressOf viewer_InteractiveUserRectangle
End Sub

Private Sub viewer_InteractiveUserRectangle(ByVal sender As Object, ByVal e As RasterViewerRectangleEventArgs)
   ' Check the status of the event
   If (e.Status = RasterViewerInteractiveStatus.End AndAlso Not e.Cancel) Then
      ' The user has finished drawing a new rectangle (and the operation has not been canceled)

      ' Get the rectangle and convert it to image coordinates (with view-perspective)
      Dim viewer As RasterImageViewer = CType(sender, RasterImageViewer)
      Dim rect As Rectangle = e.Rectangle

      ' The user rectangle might have negative width or height (if the user starts the drawing from
      ' bottom-left corner for example), check for that
      If (rect.Left > rect.Right) Then
         rect = Rectangle.FromLTRB(rect.Right, rect.Top, rect.Left, rect.Bottom)
      End If
      If (rect.Top > rect.Bottom) Then
         rect = Rectangle.FromLTRB(rect.Left, rect.Bottom, rect.Right, rect.Top)
      End If

      ' Account for the view perspective of the image
      rect = viewer.ViewerToImageRectangle(rect, True)

      ' Set this as the region and invert the colors
      Dim image As RasterImage = viewer.Image

      Dim lrect As LeadRect = New LeadRect(rect.Left, rect.Top, rect.Width, rect.Height)
      image.AddRectangleToRegion(Nothing, lrect, RasterRegionCombineMode.Set)
      Dim cmd As New InvertCommand()
      cmd.Run(image)

      ' Remove the region
      image.MakeRegionEmpty()
   End If
End Sub

public void InteractiveUserRectangleExample(RasterImageViewer viewer)
{
   // Set the interactive mode of the viewer to user-defined rectangle
   viewer.InteractiveMode = RasterViewerInteractiveMode.UserRectangle;
   // Subscribe to the InteractiveUserRectangle event to know when the user has finished drawing a new rectangle
   viewer.InteractiveUserRectangle += new EventHandler<RasterViewerRectangleEventArgs>(viewer_InteractiveUserRectangle);
}

private void viewer_InteractiveUserRectangle(object sender, RasterViewerRectangleEventArgs e)
{
   // Check the status of the event
   if(e.Status == RasterViewerInteractiveStatus.End && !e.Cancel)
   {
      // The user has finished drawing a new rectangle (and the operation has not been canceled)

      // Get the rectangle and convert it to image coordinates (with view-perspective)
      RasterImageViewer viewer = sender as RasterImageViewer;
      Rectangle rect = e.Rectangle;

      // The user rectangle might have negative width or height (if the user starts the drawing from
      // bottom-left corner for example), check for that
      if(rect.Left > rect.Right)
         rect = Rectangle.FromLTRB(rect.Right, rect.Top, rect.Left, rect.Bottom);
      if(rect.Top > rect.Bottom)
         rect = Rectangle.FromLTRB(rect.Left, rect.Bottom, rect.Right, rect.Top);

      // Account for the view perspective of the image
      rect = viewer.ViewerToImageRectangle(rect, true);

      // Set this as the region and invert the colors
      RasterImage image = viewer.Image;

      LeadRect ltRect = new LeadRect(rect.Left, rect.Top, rect.Width, rect.Height);
      image.AddRectangleToRegion(null, ltRect, RasterRegionCombineMode.Set);

      InvertCommand cmd = new InvertCommand();
      cmd.Run(image);

      // Remove the region
      image.MakeRegionEmpty();
   }
}