LEADTOOLS Image File Support (Leadtools.Codecs assembly) Send comments on this topic. | Back to Introduction - All Topics | Help Version 17.0.3.29
ReadThumbnail(String,CodecsThumbnailOptions,Int32) Method
See Also 
Leadtools.Codecs Namespace > RasterCodecs Class > ReadThumbnail Method : ReadThumbnail(String,CodecsThumbnailOptions,Int32) Method



fileName
A System.String containing the name of the file from which the thumbnail image will be created.
options
Options for creating the thumbnail image.
pageNumber
1-based index of the page from which the thumbnail image should be created.
fileName
A System.String containing the name of the file from which the thumbnail image will be created.
options
Options for creating the thumbnail image.
pageNumber
1-based index of the page from which the thumbnail image should be created.
Creates a thumbnail from the specified image file.

Syntax

Visual Basic (Declaration) 
Overloads Public Function ReadThumbnail( _
   ByVal fileName As String, _
   ByVal options As CodecsThumbnailOptions, _
   ByVal pageNumber As Integer _
) As RasterImage
Visual Basic (Usage)Copy Code
Dim instance As RasterCodecs
Dim fileName As String
Dim options As CodecsThumbnailOptions
Dim pageNumber As Integer
Dim value As RasterImage
 
value = instance.ReadThumbnail(fileName, options, pageNumber)
C# 
public RasterImage ReadThumbnail( 
   string fileName,
   CodecsThumbnailOptions options,
   int pageNumber
)
C++/CLI 
public:
RasterImage^ ReadThumbnail( 
   String^ fileName,
   CodecsThumbnailOptions options,
   int pageNumber
) 

Parameters

fileName
A System.String containing the name of the file from which the thumbnail image will be created.
options
Options for creating the thumbnail image.
pageNumber
1-based index of the page from which the thumbnail image should be created.

Return Value

The Leadtools.RasterImage object that this method creates.

Example

This example will read a thumbnail from a CMP file

Visual BasicCopy Code
Public Sub ReadThumbnailExample()
      Dim codecs As RasterCodecs = New RasterCodecs()

      Dim srcFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp")

      ' Create a thumbnail with default options
      Dim options As CodecsThumbnailOptions = CodecsThumbnailOptions.Default
      options.LoadStamp = False
      Dim thumbnail As RasterImage = codecs.ReadThumbnail(srcFileName, options, 1)

      Console.WriteLine("Thumbnail with default option:")
      Console.WriteLine("  Size: {0} by {1} pixels. Bits/Pixel: {2}", thumbnail.Width, thumbnail.Height, thumbnail.BitsPerPixel)
      thumbnail.Dispose()

      ' Create a thumbnail with some options
      options.LoadStamp = False
      options.Width = 40
      options.Height = 80
      options.ForceSize = True
      options.MaintainAspectRatio = False
      options.BackColor = RasterColor.FromKnownColor(RasterKnownColor.LightBlue)
      options.BitsPerPixel = 8
      thumbnail = codecs.ReadThumbnail(srcFileName, options, 1)

      Console.WriteLine("Thumbnail with set option (size: {0} by {1}, Bits/Pixel: {2}, ForeSize: {3}", options.Width, options.Height, options.BitsPerPixel, options.ForceSize)
      Console.WriteLine("  Size: {0} by {1} pixels. Bits/Pixel: {2}", thumbnail.Width, thumbnail.Height, thumbnail.BitsPerPixel)
      thumbnail.Dispose()

      codecs.Dispose()
   End Sub

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class
C#Copy Code
public void ReadThumbnailExample()
   {
      RasterCodecs codecs = new RasterCodecs();

      string srcFileName = Path.Combine(LEAD_VARS.ImagesDir,"Image1.cmp");

      // Create a thumbnail with default options
      CodecsThumbnailOptions options = CodecsThumbnailOptions.Default;
      options.LoadStamp = false;
      RasterImage thumbnail = codecs.ReadThumbnail(srcFileName, options, 1);

      Console.WriteLine("Thumbnail with default option:");
      Console.WriteLine("  Size: {0} by {1} pixels. Bits/Pixel: {2}", thumbnail.Width, thumbnail.Height, thumbnail.BitsPerPixel);
      thumbnail.Dispose();

      // Create a thumbnail with some options
      options.LoadStamp = false;
      options.Width = 40;
      options.Height = 80;
      options.ForceSize = true;
      options.MaintainAspectRatio = false;
      options.BackColor = RasterColor.FromKnownColor(RasterKnownColor.LightBlue);
      options.BitsPerPixel = 8;
      thumbnail = codecs.ReadThumbnail(srcFileName, options, 1);

      Console.WriteLine("Thumbnail with set option (size: {0} by {1}, Bits/Pixel: {2}, ForeSize: {3}",
         options.Width, options.Height, options.BitsPerPixel, options.ForceSize);
      Console.WriteLine("  Size: {0} by {1} pixels. Bits/Pixel: {2}", thumbnail.Width, thumbnail.Height, thumbnail.BitsPerPixel);
      thumbnail.Dispose();

      codecs.Dispose();
   }

static class LEAD_VARS
{
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}
SilverlightCSharpCopy Code
public void ReadThumbnailExample(Stream inStreamCmp)
{
   RasterCodecs codecs = new RasterCodecs();
   // Create a thumbnail with default options
   CodecsThumbnailOptions options = CodecsThumbnailOptions.Default;
   options.LoadStamp = false;
   RasterImage thumbnail = codecs.ReadThumbnail(inStreamCmp, options, 1);

   Debug.WriteLine("Thumbnail with default option:");
   Debug.WriteLine("  Size: {0} by {1} pixels. Bits/Pixel: {2}", thumbnail.Width, thumbnail.Height, thumbnail.BitsPerPixel);
   thumbnail.Dispose();

   // Create a thumbnail with some options
   options.LoadStamp = false;
   options.Width = 40;
   options.Height = 80;
   options.ForceSize = true;
   options.MaintainAspectRatio = false;
   options.BackColor = new RasterColor(0x00, 0x00, 0x7F);
   options.BitsPerPixel = 8;
   thumbnail = codecs.ReadThumbnail(inStreamCmp, options, 1);

   Debug.WriteLine("Thumbnail with set option (size: {0} by {1}, Bits/Pixel: {2}, ForeSize: {3}",
      options.Width, options.Height, options.BitsPerPixel, options.ForceSize);
   Debug.WriteLine("  Size: {0} by {1} pixels. Bits/Pixel: {2}", thumbnail.Width, thumbnail.Height, thumbnail.BitsPerPixel);
   thumbnail.Dispose();
}
SilverlightVBCopy Code
Public Sub ReadThumbnailExample(ByVal inStreamCmp As Stream)
   Dim codecs As RasterCodecs = New RasterCodecs()
   ' Create a thumbnail with default options
   Dim options As CodecsThumbnailOptions = CodecsThumbnailOptions.Default
   options.LoadStamp = False
   Dim thumbnail As RasterImage = codecs.ReadThumbnail(inStreamCmp, options, 1)

   Debug.WriteLine("Thumbnail with default option:")
   Debug.WriteLine("  Size: {0} by {1} pixels. Bits/Pixel: {2}", thumbnail.Width, thumbnail.Height, thumbnail.BitsPerPixel)
   thumbnail.Dispose()

   ' Create a thumbnail with some options
   options.LoadStamp = False
   options.Width = 40
   options.Height = 80
   options.ForceSize = True
   options.MaintainAspectRatio = False
   options.BackColor = New RasterColor(&H00, &H00, &H7F)
   options.BitsPerPixel = 8
   thumbnail = codecs.ReadThumbnail(inStreamCmp, options, 1)

   Debug.WriteLine("Thumbnail with set option (size: {0} by {1}, Bits/Pixel: {2}, ForeSize: {3}", options.Width, options.Height, options.BitsPerPixel, options.ForceSize)
   Debug.WriteLine("  Size: {0} by {1} pixels. Bits/Pixel: {2}", thumbnail.Width, thumbnail.Height, thumbnail.BitsPerPixel)
   thumbnail.Dispose()
End Sub

Remarks

This method will always return a thumbnail image. Depending on the options passed, this method might read the stamp stored inside EXIF, CMP, JFIF and FlashPix files and return that. To read the file stamp only, use ReadStamp(String,Int32).

Requirements

Target Platforms: Silverlight, Windows XP, Windows Server 2003 family, Windows Server 2008 family, Windows Vista, Windows 7, MAC OS/X (Intel Only)

See Also