LEADTOOLS WPF and Silverlight (Leadtools.Windows.Controls assembly)

CenterAtPoint Method

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Example 





The point at which to center the image display, in client coordinates.
Centers the image display at the specified point.
Syntax
public virtual void CenterAtPoint( 
   Point pt
)
'Declaration
 
Public Overridable Sub CenterAtPoint( _
   ByVal pt As Point _
) 
'Usage
 
Dim instance As ImageViewer
Dim pt As Point
 
instance.CenterAtPoint(pt)

            

            
public:
virtual void CenterAtPoint( 
   Point pt
) 

Parameters

pt
The point at which to center the image display, in client coordinates.
Remarks

The control will position the scrollbars according to user cursor moves, therefore, this method is only functional if the control has visible scrollbars (SizeMode is SizeMode.Normal or SizeMode.FitWidth and the view port is less than the image size).

The control will call this method during InteractiveMode.Pan.

Example
Copy Code  
Imports Leadtools.Windows.Controls

  Private Sub ZoomAndCenter(ByVal viewer As ImageViewer, 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 Rect = Rect.Intersect(New Rect(0, 0, viewer.ActualWidth, viewer.ActualHeight), New Rect(viewer.PhysicalSize))

      ' Get the center of what you see in physical coordinates
      Dim center As Point = New Point(rc.Left + rc.Width / 2 * scaleFactor, rc.Top + rc.Height / 2 * scaleFactor)

      ' Set the new scale factor
      viewer.ScaleFactor = scaleFactor

      ' Bring the old center into the center of the view
      viewer.CenterAtPoint(center)
   End If
End Sub
using Leadtools.Help;
using Leadtools.Windows.Controls;

void ZoomAndCenter(ImageViewer 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
      Rect rc = Rect.Intersect(new Rect(0, 0, viewer.ActualWidth, viewer.ActualHeight), new Rect(viewer.PhysicalSize));

      // Get the center of what you see in physical coordinates
      Point center = new Point(rc.Left + rc.Width / 2 * scaleFactor, rc.Top + rc.Height / 2 * scaleFactor);

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

      // Bring the old center into the center of the view
      viewer.CenterAtPoint(center);
   }
}
using Leadtools.Help;
using Leadtools.Windows.Controls;

void ZoomAndCenter(ImageViewer 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
      LeadRect rc = LeadRect.Intersect(new LeadRect(0, 0, (int)viewer.ActualWidth, (int)viewer.ActualHeight), new LeadRect(0, 0, (int)viewer.PhysicalSize.Width, (int)viewer.PhysicalSize.Height));

      // Get the center of what you see in physical coordinates
      Point center = new Point(rc.Left + rc.Width / 2 * scaleFactor, rc.Top + rc.Height / 2 * scaleFactor);

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

      // Bring the old center into the center of the view
      viewer.CenterAtPoint(center);
   }
}
Imports Leadtools
Imports Leadtools.Windows.Controls

Private Sub ZoomAndCenter(ByVal viewer As ImageViewer, 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 LeadRect = LeadRect.Intersect(New LeadRect(0, 0, CInt(viewer.ActualWidth), CInt(viewer.ActualHeight)), New LeadRect(0, 0, CInt(viewer.PhysicalSize.Width), CInt(viewer.PhysicalSize.Height)))

      ' Get the center of what you see in physical coordinates
      Dim center As Point = New Point(rc.Left + rc.Width / 2 * scaleFactor, rc.Top + rc.Height / 2 * scaleFactor)

      ' Set the new scale factor
      viewer.ScaleFactor = scaleFactor

      ' Bring the old center into the center of the view
      viewer.CenterAtPoint(center)
   End If
End Sub
Requirements

Target Platforms

See Also

Reference

ImageViewer Class
ImageViewer Members

 

 


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