RubberBandStarted Event

using Leadtools; 
using Leadtools.Controls; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
 
public ImageViewerForm _form = new ImageViewerForm(); 
public ComboBox _rubberBandShapesComboBox = new ComboBox(); 
public ImageViewer _imageViewer; 
 
public void ImageViewerRubberBandInteractiveModeExample() 
{ 
   // Get the ImageViewer control from the form 
   _imageViewer = _form.ImageViewer; 
 
   // Load an image 
   using (var codecs = new RasterCodecs()) 
      _imageViewer.Image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "image1.cmp")); 
 
   // Add rubber band shape ComboBox to the form 
   _form.Controls.Add(_rubberBandShapesComboBox); 
   _rubberBandShapesComboBox.BringToFront(); 
 
   // Add the shapes to the ComboBox 
   foreach (ImageViewerRubberBandShape shape in Enum.GetValues(typeof(ImageViewerRubberBandShape))) 
      _rubberBandShapesComboBox.Items.Add(shape); 
 
   // Create the interactive mode  
   ImageViewerRubberBandInteractiveMode rubberBandMode = new ImageViewerRubberBandInteractiveMode(); 
   rubberBandMode.BackgroundBrush = null; 
   rubberBandMode.BorderPen = new Pen(Color.FromArgb(0xEF, 128, 128, 0)) { DashStyle = DashStyle.Dash }; 
 
   // Set the default shape as selected in the ComboBox 
   _rubberBandShapesComboBox.SelectedItem = rubberBandMode.Shape; 
 
   // Set the selected ComboBox item as the shape for the interactive mode 
   _rubberBandShapesComboBox.SelectedIndexChanged += (sender, e) => rubberBandMode.Shape = (ImageViewerRubberBandShape)_rubberBandShapesComboBox.SelectedItem; 
 
   //  
   rubberBandMode.RubberBandStarted += (object sender, ImageViewerRubberBandEventArgs e) => 
   { 
      Debug.WriteLine("Rubber-Band started at " + e.Points[0].X + ", " + e.Points[0].Y); 
   }; 
 
   rubberBandMode.RubberBandDelta += (object sender, ImageViewerRubberBandEventArgs e) => 
   { 
      int left = e.Points[0].X; 
      int top = e.Points[0].Y; 
      LeadPoint lastPoint = e.Points[e.Points.Count - 1]; 
      int width = lastPoint.X > left ? lastPoint.X - left : left - lastPoint.X; 
      int height = lastPoint.Y > top ? lastPoint.Y - top : top - lastPoint.Y; 
 
      _form.Text = "Rubber-Band Region: " + left + ", " + top + ", " + width + ", " + height; 
   }; 
 
   // Handle drawing the shape when rubber band selection is complete 
   rubberBandMode.RubberBandCompleted += (object sender, ImageViewerRubberBandEventArgs e) => 
   { 
      if (e.IsCanceled) 
         return; 
 
      if (rubberBandMode.Item == null) 
         return; 
 
      LeadPoint[] points = new LeadPoint[e.Points.Count]; 
      for (var i = 0; i < points.Length; i++) 
         points[i] = LeadPoint.Create(e.Points[i].X, e.Points[i].Y); 
 
      LeadPoint min = LeadPoint.Empty; 
      LeadPoint max = LeadPoint.Empty; 
 
      for (int i = 0; i < points.Length; i++) 
      { 
         points[i] = _imageViewer.ConvertPoint(rubberBandMode.Item, ImageViewerCoordinateType.Control, ImageViewerCoordinateType.Image, points[i]); 
         if (i == 0) 
         { 
            min = points[i]; 
            max = points[i]; 
         } 
         else 
         { 
            min.X = Math.Min(min.X, points[i].X); 
            min.Y = Math.Min(min.Y, points[i].Y); 
            max.X = Math.Max(max.X, points[i].X); 
            max.Y = Math.Max(max.Y, points[i].Y); 
         } 
      } 
 
      LeadPoint center = LeadPoint.Create(min.X + (max.X - min.X) / 2, min.Y + (max.Y - min.Y) / 2); 
 
      ImageViewerItem rasterItem = rubberBandMode.Item; 
      RasterImage image = rasterItem.Image; 
      IntPtr hdc = RasterImagePainter.CreateLeadDC(image); 
      using (Graphics graphics = Graphics.FromHdc(hdc)) 
      { 
         using (GraphicsPath path = new GraphicsPath()) 
         { 
            switch (rubberBandMode.Shape) 
            { 
               case ImageViewerRubberBandShape.Rectangle: 
               case ImageViewerRubberBandShape.Ellipse: 
                  { 
                     LeadRect rect = LeadRect.Normalize(LeadRect.FromLTRB(points[0].X, points[0].Y, points[1].X, points[1].Y)); 
                     Rectangle rc = new Rectangle(rect.X, rect.Y, rect.Width, rect.Height); 
                     if (rubberBandMode.Shape == ImageViewerRubberBandShape.Rectangle) 
                        path.AddRectangle(rc); 
                     else 
                        path.AddEllipse(rc); 
                  } 
                  break; 
 
               case ImageViewerRubberBandShape.RoundRectangle: 
                  { 
                     LeadSize radius = rubberBandMode.RoundRectangleRadius; 
                     LeadRect rect = LeadRect.Normalize(LeadRect.FromLTRB(points[0].X, points[0].Y, points[1].X, points[1].Y)); 
                     AddRoundRect(path, rect, radius.Width, radius.Height); 
                  } 
                  break; 
 
               case ImageViewerRubberBandShape.Freehand: 
                  { 
                     bool firstPoint = true; 
                     LeadPoint lastPoint = LeadPoint.Empty; 
 
                     foreach (LeadPoint pt in points) 
                     { 
                        if (!firstPoint) 
                           path.AddLine(lastPoint.X, lastPoint.Y, pt.X, pt.Y); 
                        else 
                           firstPoint = false; 
 
                        lastPoint = pt; 
                     } 
                  } 
                  break; 
 
               default: 
                  break; 
            } 
 
            path.CloseFigure(); 
 
            if (image.Width > 1000 || image.Height > 1000) 
            { 
               using (Pen pen = new Pen(Color.Yellow, 8)) 
                  graphics.DrawPath(pen, path); 
            } 
            else 
            { 
               graphics.DrawPath(Pens.Yellow, path); 
            } 
         } 
      } 
 
      RasterImagePainter.DeleteLeadDC(hdc); 
      _imageViewer.Invalidate(); 
   }; 
 
   rubberBandMode.AutoItemMode = ImageViewerAutoItemMode.AutoSet; 
   rubberBandMode.ItemPart = ImageViewerItemPart.Image; 
   _imageViewer.InteractiveModes.BeginUpdate(); 
   _imageViewer.InteractiveModes.Add(rubberBandMode); 
   ImageViewerAutoPanInteractiveMode autopan = new ImageViewerAutoPanInteractiveMode(); 
   autopan.PanDelay = 100; 
   _imageViewer.InteractiveModes.Add(autopan); 
   _imageViewer.InteractiveModes.EndUpdate(); 
} 
 
// Draw a round rectangle 
public static bool AddRoundRect(GraphicsPath path, LeadRect bounds, int xRadius, int yRadius) 
{ 
   if (bounds.Width < 1 || bounds.Height < 1) 
      return false; 
 
   if (xRadius < 1 || yRadius < 1) 
   { 
      // Add a rectangle 
      path.AddRectangle(new Rectangle(bounds.X, bounds.Y, bounds.Width, bounds.Height)); 
      return true; 
   } 
 
   int x = bounds.X; 
   int y = bounds.Y; 
   int width = bounds.Width; 
   int height = bounds.Height; 
 
   // adapt horizontal and vertical diameter if the rectangle is too little 
   int xDiameter = xRadius * 2; 
   int yDiameter = yRadius * 2; 
   if (width < (xDiameter)) 
      xDiameter = width; 
   if (height < (yDiameter)) 
      yDiameter = height; 
   xRadius = xDiameter / 2; 
   yRadius = yDiameter / 2; 
 
   int xw = x + width; 
   int yh = y + height; 
   int xwr = xw - xRadius; 
   int yhr = yh - yRadius; 
   int xr = x + xRadius; 
   int yr = y + yRadius; 
   int xwr2 = xw - xDiameter; 
   int yhr2 = yh - yDiameter; 
 
   path.StartFigure(); 
 
   path.AddArc(x, y, xDiameter, yDiameter, 180, 90); 
   path.AddLine(xr, y, xwr, y); 
   path.AddArc(xwr2, y, xDiameter, yDiameter, 270, 90); 
   path.AddLine(xw, yr, xw, yhr); 
   path.AddArc(xwr2, yhr2, xDiameter, yDiameter, 0, 90); 
   path.AddLine(xwr, yh, xr, yh); 
   path.AddArc(x, yhr2, xDiameter, yDiameter, 90, 90); 
   path.AddLine(x, yhr, x, yr); 
   path.CloseFigure(); 
 
   return true; 
} 
 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS23\Resources\Images"; 
}