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ReadExtensions(String,Int32) Method
See Also  Example
Leadtools.Codecs Namespace > RasterCodecs Class > ReadExtensions Method : ReadExtensions(String,Int32) Method



fileName
The input file name.
pageNumber
1-based index of the page within the file that contains the extension.
Loads extensions from the specified Exif file.

Syntax

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

Parameters

fileName
The input file name.
pageNumber
1-based index of the page within the file that contains the extension.

Return Value

An CodecsExtensionList object that contains the extensions found in this file.

Example

This example will show detailed information on the streams present in the Exif file.

Visual BasicCopy Code
Private Sub ExtensionsExample(ByVal exifFileName As String)
   RasterCodecs.Startup()
   Dim codecs As RasterCodecs = New RasterCodecs()
   Dim stampFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "Extension.bmp"
   Dim audioFileNameTemplate As String = LeadtoolsExamples.Common.ImagesPath.Path + "Extension{0}.wav"

   ' Read the extensions from the file
   Console.WriteLine("Reading the extensions from the exif file")
   Dim extensionList As CodecsExtensionList = codecs.ReadExtensions(exifFileName, 1)
   If Not extensionList Is Nothing Then
      If (extensionList.Flags And CodecsExtensionListFlags.Stamp) = CodecsExtensionListFlags.Stamp Then
         Console.WriteLine("Stamp extension: Found, saving to {0}", stampFileName)
         Dim stampImage As RasterImage = extensionList.CreateStamp()
         codecs.Save(stampImage, stampFileName, RasterImageFormat.Bmp, 24)
         stampImage.Dispose()
      Else
         Console.WriteLine("Stamp extension: Not found")
      End If

      If (extensionList.Flags And CodecsExtensionListFlags.Audio) = CodecsExtensionListFlags.Audio Then
         Console.WriteLine("Audio extension: Found, saving ...")
         Dim audioData As RasterNativeBuffer
         Dim streamIndex As Integer = 0

         Do
            audioData = extensionList.GetAudioData(streamIndex)
            If audioData.Data <> IntPtr.Zero Then
               Dim audioFileName As String = String.Format(audioFileNameTemplate, streamIndex)
               Console.WriteLine("To {0}", audioFileName)
               Using fs As FileStream = File.Create(audioFileName)
                  Dim data As Byte() = New Byte(CInt(audioData.Length) - 1) {}
                  Marshal.Copy(audioData.Data, data, 0, CInt(audioData.Length))
                  fs.Write(data, 0, CInt(audioData.Length))
               End Using

               streamIndex += 1
            End If
         Loop While audioData.Data <> IntPtr.Zero

         Console.WriteLine("{0} total audio streams found", streamIndex)
      Else
         Console.WriteLine("Audio extension: Not found")
      End If

      Dim extensions As CodecsExtension() = extensionList.GetExtensions()
      Console.WriteLine("Total number of extensions found in the file: {0}", extensions.Length)

      Dim i As Integer = 0
      Do While i < extensions.Length
         Dim extension As CodecsExtension = extensions(i)
         Console.WriteLine(" {0}. Name: {1}, Clsid: {2}, UCDefault: {3}, DatLength: {4}", i, extension.Name, extension.Clsid, extension.UCDefault, extension.DataLength)
         i += 1
      Loop

      extensionList.Dispose()
   Else
      Console.WriteLine("No extensions were found in the file")
   End If

   codecs.Dispose()
   RasterCodecs.Shutdown()
End Sub
C#Copy Code
void ExtensionsExample(string exifFileName) 
{ 
   RasterCodecs.Startup(); 
   RasterCodecs codecs = new RasterCodecs(); 
   string stampFileName = LeadtoolsExamples.Common.ImagesPath.Path + "Extension.bmp"; 
   string audioFileNameTemplate = LeadtoolsExamples.Common.ImagesPath.Path + "Extension{0}.wav"; 
 
   // Read the extensions from the file 
   Console.WriteLine("Reading the extensions from the exif file"); 
   CodecsExtensionList extensionList = codecs.ReadExtensions(exifFileName, 1); 
   if(extensionList != null) 
   { 
      if((extensionList.Flags & CodecsExtensionListFlags.Stamp) == CodecsExtensionListFlags.Stamp) 
      { 
         Console.WriteLine("Stamp extension: Found, saving to {0}", stampFileName); 
         RasterImage stampImage = extensionList.CreateStamp(); 
         codecs.Save(stampImage, stampFileName, RasterImageFormat.Bmp, 24); 
         stampImage.Dispose(); 
      } 
      else 
         Console.WriteLine("Stamp extension: Not found"); 
 
      if((extensionList.Flags & CodecsExtensionListFlags.Audio) == CodecsExtensionListFlags.Audio) 
      { 
         Console.WriteLine("Audio extension: Found, saving ..."); 
         RasterNativeBuffer audioData; 
         int streamIndex = 0; 
 
         do 
         { 
            audioData = extensionList.GetAudioData(streamIndex); 
            if(audioData.Data != IntPtr.Zero) 
            { 
               string audioFileName = string.Format(audioFileNameTemplate, streamIndex); 
               Console.WriteLine("To {0}", audioFileName); 
               using(FileStream fs = File.Create(audioFileName)) 
               { 
                  byte[] data = new byte[audioData.Length]; 
                  Marshal.Copy(audioData.Data, data, 0, (int)audioData.Length); 
                  fs.Write(data, 0, (int)audioData.Length); 
               } 
 
               streamIndex++; 
            } 
         } 
         while(audioData.Data != IntPtr.Zero); 
 
         Console.WriteLine("{0} total audio streams found", streamIndex); 
      } 
      else 
         Console.WriteLine("Audio extension: Not found"); 
 
      CodecsExtension[] extensions = extensionList.GetExtensions(); 
      Console.WriteLine("Total number of extensions found in the file: {0}", extensions.Length); 
 
      for(int i = 0; i < extensions.Length; i++) 
      { 
         CodecsExtension extension = extensions[i]; 
         Console.WriteLine(" {0}. Name: {1}, Clsid: {2}, UCDefault: {3}, DatLength: {4}", 
            i, extension.Name, extension.Clsid, extension.UCDefault, extension.DataLength); 
      } 
 
      extensionList.Dispose(); 
   } 
   else 
      Console.WriteLine("No extensions were found in the file"); 
 
   codecs.Dispose(); 
   RasterCodecs.Shutdown(); 
}

Remarks

Please note that not all Exif files have extensions.

Currently, this method works only with Exif files. Exif files can contain extra data stored as "FlashPix extensions". This method can be used to access this extra data. Leadtools refers to this extra data as "extensions".

You must dispose the CodecsExtensionList returned from this method when you are done using it.

Requirements

Target Platforms: Microsoft .NET Framework 3.0, Windows XP, Windows Server 2003 family, Windows Server 2008 family

See Also