Public Overridable Sub CenterAtPoint( _
   ByVal pt As Point _
) 

Dim instance As RasterImageViewer
Dim pt As Point
 
instance.CenterAtPoint(pt)

public virtual void CenterAtPoint( 
   Point pt
)

public:
virtual void CenterAtPoint( 
   Point pt
) 

Sub ZoomAndCenter(ByVal viewer As RasterImageViewer, ByVal scaleFactor As Double)
   ' Minimum and maximum scale factors allowed (change if you have to)
   Const minimumScaleFactor As Double = 0.05
   Const maximumScaleFactor As Double = 11
   ' Normalize the scale factor based on min and max
   scaleFactor = Math.Max(minimumScaleFactor, Math.Min(maximumScaleFactor, scaleFactor))

   ' Check if we need to change the scale factor for the viewer
   If (viewer.ScaleFactor <> scaleFactor) Then
      ' Get the current center in logical units
      ' We will use this point later to re-center the viewer

      ' Get what you see in physical coordinates
      Dim rc As Rectangle = Rectangle.Intersect(viewer.PhysicalViewRectangle, viewer.ClientRectangle)
      ' Get the center of what you see in physical coordinates
      Dim center As New PointF(rc.Left + rc.Width \ 2, rc.Top + rc.Height \ 2)
      Dim t As New Transformer(viewer.Transform)
      ' Get the center of what you see in logical coordinates
      center = t.PointToLogical(center)

      ' Set the new scale factor
      viewer.ScaleFactor = scaleFactor

      ' Bring the original center into the view center

      t = New Transformer(viewer.Transform)
      ' Get the center of what you saw before the zoom in physical coordinates
      center = t.PointToPhysical(center)
      ' Bring the old center into the center of the view
      viewer.CenterAtPoint(Point.Round(center))
   End If
End Sub

void ZoomAndCenter(RasterImageViewer viewer, double scaleFactor)
{
   // Minimum and maximum scale factors allowed (change if you have to)
   const double minimumScaleFactor = 0.05;
   const double maximumScaleFactor = 11;
   // Normalize the scale factor based on min and max
   scaleFactor = Math.Max(minimumScaleFactor, Math.Min(maximumScaleFactor, scaleFactor));

   // Check if we need to change the scale factor for the viewer
   if(viewer.ScaleFactor != scaleFactor)
   {
      // Get the current center in logical units
      // We will use this point later to re-center the viewer

      // Get what you see in physical coordinates
      Rectangle rc = Rectangle.Intersect(viewer.PhysicalViewRectangle, viewer.ClientRectangle);
      // Get the center of what you see in physical coordinates
      PointF center = new PointF(rc.Left + rc.Width / 2, rc.Top + rc.Height / 2);
      Transformer t = new Transformer(viewer.Transform);
      // Get the center of what you see in logical coordinates
      center = t.PointToLogical(center);

      // Set the new scale factor
      viewer.ScaleFactor = scaleFactor;

      // Bring the original center into the view center

      t = new Transformer(viewer.Transform);
      // Get the center of what you saw before the zoom in physical coordinates
      center = t.PointToPhysical(center);
      // Bring the old center into the center of the view
      viewer.CenterAtPoint(Point.Round(center));
   }
}