GetItemViewBounds Method

Summary

Current physical (in control pixel coordinates) bounds of any part of an item.

Syntax

C++

public virtual LeadRectD GetItemViewBounds( 
   ImageViewerItem item, 
   ImageViewerItemPart part, 
   bool clipped 
)

Public Overridable Function GetItemViewBounds( 
   ByVal item As ImageViewerItem, 
   ByVal part As ImageViewerItemPart, 
   ByVal clipped As Boolean 
) As LeadRectD

public:  
   virtual LeadRectD^ GetItemViewBounds( 
      ImageViewerItem^ item, 
      ImageViewerItemPart^ part, 
      bool clipped 
   )

Parameters

item

The item. Must be a valid item inside this viewer.

part

The item part requested.

clipped

true to return the bounding rectangle intersected with the current viewer control area, otherwise; false.

Return Value

The bounding rectangle in pixels or LeadRectD.Empty if the item is not visible, does not have an image or outside the clipping area.

Remarks

Use ConvertBoundsToView to convert a bound from logical to physical coordinates.

For more information refer to Image Viewer Appearance, Image Viewer Transformation, and Image Viewer Bounds and Transform.

Example

This example will show how to use GetItemBounds to perform manual hit-testing on the item.

Start with the ImageViewer example, remove all the code inside the example function (search for the "// TODO: add example code here" comment) and insert the following code:

using Leadtools; 
using Leadtools.Controls; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
 
 
public void GetItemViewBounds_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); 
      } 
   } 
 
   // Hook to the viewer mouse click event 
   _imageViewer.MouseClick += (sender, e) => 
   { 
      // Loop through each item, get the view bounds of the image (the physical location and size on the viewer surface of the item) 
      // and perform hit-testing 
      foreach (var item in _imageViewer.Items) 
      { 
         // Pass part as image and clipped as true, we are only interested on what we are seeing 
         var bounds = _imageViewer.GetItemViewBounds(item, ImageViewerItemPart.Image, true); 
         // Hit-test. GetItemViewBounds returns the value in the control coordinates, same as the mouse click 
         if (bounds.Contains(e.X, e.Y)) 
         { 
            MessageBox.Show("Clicked the image of item at index " + _imageViewer.Items.IndexOf(item)); 
            return; 
         } 
      } 
   }; 
 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS21\Resources\Images"; 
}

Imports Leadtools 
Imports Leadtools.Controls 
Imports Leadtools.Codecs 
Imports Leadtools.Drawing 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Color 
Imports LeadtoolsControlsExamples.LeadtoolsExamples.Common 
 
Public Sub GetItemViewBounds_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 codecs As New RasterCodecs() 
      For page As Integer = 1 To 4 
         Dim item As New ImageViewerItem() 
         Dim fileName As String = Path.Combine(ImagesPath.Path, String.Format("ocr{0}.tif", page)) 
 
         ' Create a thumbnail from the image 
         Using image As RasterImage = codecs.Load(fileName, page) 
            item.Image = image.CreateThumbnail(180, 180, 24, RasterViewPerspective.TopLeft, RasterSizeFlags.Resample) 
         End Using 
 
         item.Text = String.Format("Item {0}", page - 1) 
         _imageViewer.Items.Add(item) 
      Next page 
   End Using 
 
   ' Hook to the viewer mouse click event 
   AddHandler _imageViewer.MouseClick, 
   Sub(sender, e) 
      ' Loop through each item, get the view bounds of the image (the physical location and size on the viewer surface of the item) 
      ' and perform hit-testing 
      For Each item As ImageViewerItem In _imageViewer.Items 
         ' Pass part as image and clipped as true, we are only interested on what we are seeing 
         Dim bounds As LeadRectD = _imageViewer.GetItemViewBounds(item, ImageViewerItemPart.Image, True) 
         ' Hit-test. GetItemViewBounds returns the value in the control coordinates, same as the mouse click 
         If bounds.Contains(e.X, e.Y) Then 
            MessageBox.Show("Clicked the image of item at index " & _imageViewer.Items.IndexOf(item)) 
            Return 
         End If 
      Next item 
   End Sub 
End Sub

Requirements

Target Platforms

Reference

ImageViewer Class

ImageViewer Members

Leadtools.Controls Namespace

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Leadtools.Controls Assembly

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