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Item Property

Summary

Item to render

Syntax
C#
C++/CLI
public ImageViewerItem Item { get; } 
public:  
   property ImageViewerItem^ Item 
   { 
      ImageViewerItem^ get() 
   } 

Property Value

The item to render or null if this event is for rendering the view.

Remarks

If the value of Item is not null, then Part will contain the specific part of the item to render.

Example
C#
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"; 
} 
Requirements

Target Platforms

Help Version 22.0.2023.1.24
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© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.

Leadtools.Controls Assembly

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© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.