RenderItemRegion Event

using Leadtools; 
using Leadtools.Controls; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
 
 
public void ImageViewerPostRender_Example() 
{ 
   // Clear all the images already the viewer 
   _imageViewer.Items.Clear(); 
   // Use vertical view layout 
   _imageViewer.ViewLayout = new ImageViewerVerticalViewLayout(); 
   // Make sure the item size is larger than the image size (thumbnails mode) 
   _imageViewer.ItemSize = LeadSize.Create(200, 200); 
   _imageViewer.ItemPadding = new Padding(8, 8, 8, 20); 
   _imageViewer.ImageBorderThickness = 1; 
 
   // Add 4 items to the viewer 
   using (var codecs = new RasterCodecs()) 
   { 
      for (var page = 1; page <= 4; page++) 
      { 
         var item = new ImageViewerItem(); 
         var fileName = Path.Combine(LEAD_VARS.ImagesDir, string.Format("ocr{0}.tif", page)); 
 
         // Create a thumbnail from the image 
         using (var image = codecs.Load(fileName, page)) 
         { 
            item.Image = image.CreateThumbnail(180, 180, 24, RasterViewPerspective.TopLeft, RasterSizeFlags.Resample); 
         } 
 
         item.Text = string.Format("Item {0}", page - 1); 
         _imageViewer.Items.Add(item); 
      } 
   } 
 
   // Render on the view 
   _imageViewer.PostRender += (sender, e) => 
   { 
      // Rendering the whole view 
      var graphics = e.PaintEventArgs.Graphics; 
 
      // Blue ellipse at fixed position. This will stay the same and will not scroll or zoom 
      using (var brush = new SolidBrush(Color.FromArgb(128, Color.Blue))) 
         graphics.FillEllipse(brush, new Rectangle(0, 0, 100, 100)); 
 
      // Red ellipse at relative position, this will scroll and zoom with the view 
      var gstate = graphics.Save(); 
 
      var transform = _imageViewer.ViewTransform; 
      using (var matrix = new System.Drawing.Drawing2D.Matrix( 
         (float)transform.M11, (float)transform.M12, (float)transform.M21, (float)transform.M22, 
         (float)transform.OffsetX, (float)transform.OffsetY)) 
         graphics.MultiplyTransform(matrix); 
 
      graphics.FillEllipse(Brushes.Red, new Rectangle(0, 0, 100, 100)); 
 
      graphics.Restore(gstate); 
   }; 
 
   // Render on each item 
   _imageViewer.PostRenderItem += (sender, e) => 
   { 
      var item = e.Item; 
 
      var graphics = e.PaintEventArgs.Graphics; 
 
      var gstate = graphics.Save(); 
 
      // Get the bounding rectangle for the image 
      var bounds = LeadRectD.Create(0, 0, item.Image.ImageWidth, item.Image.ImageHeight); 
 
      // Add the image transform to the graphics 
      var transform = _imageViewer.GetItemImageTransform(item); 
      using (var matrix = new System.Drawing.Drawing2D.Matrix( 
         (float)transform.M11, (float)transform.M12, (float)transform.M21, (float)transform.M22, 
         (float)transform.OffsetX, (float)transform.OffsetY)) 
         graphics.MultiplyTransform(matrix); 
 
      // Red hilight on top of each item image 
      using (var brush = new SolidBrush(Color.FromArgb(128, Color.Red))) 
         graphics.FillRectangle(brush, (float)bounds.X, (float)bounds.Y, (float)bounds.Width, (float)bounds.Height); 
 
      graphics.Restore(gstate); 
   }; 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images"; 
}