ExtractFramesMemory(Stream,List<Int32>) Method

Extracts the specified frames from the input stream, and saves them to a new JPEG 2000 file in a byte array. This method is available in the Document/Medical Toolkits.

Syntax

Visual Basic
C#
WinRT C#
WinRT JavaScript
C++/CLI

public byte[] ExtractFramesMemory( 
   Stream stream,
   List<int> frames
)

'Declaration
 
Public Overloads Function ExtractFramesMemory( _
   ByVal stream As Stream, _
   ByVal frames As List(Of Integer) _
) As Byte()

'Usage
 
Dim instance As Jpeg2000Engine
Dim stream As Stream
Dim frames As List(Of Integer)
Dim value() As Byte
 
value = instance.ExtractFramesMemory(stream, frames)

public byte[] ExtractFramesMemory( 
   Stream stream,
   List<int> frames
)

 function Leadtools.Jpeg2000.Jpeg2000Engine.ExtractFramesMemory(Stream,List{Int32})( 
   stream ,
   frames 
)

public:
array<byte>^ ExtractFramesMemory( 
   Stream^ stream,
   List<int>^ frames
)

Parameters

stream: A System.IO.Stream containing the JPEG 2000 file data from which the frames are being extracted.
frames: Frame indices. A list of integers specifying the indices of the frames to be extracted from the input file. All indices should be 0-based.

Return Value

A byte array that contains a JPEG 2000 file with extracted frames only.

Remarks

This file contains only the extracted frame headers/code streams (not any obtained through the decompressing/recompressing process) so it saves processor time and memory.

This method is very suitable for server applications where multiple clients request specific frames of a JPEG 2000 file. Instead of decompressing and then recompressing the frames this method copies only the needed frame data, saving the data to a new JPEG 2000 file.

Example

Visual Basic
C#
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Private Function ExtractFramesMemoryStreamExample(ByVal frames As List(Of Integer)) As Byte()
      Dim fs As FileStream = File.OpenRead(Path.Combine(LEAD_VARS.ImagesDir, "image1.jpx"))

      Dim engine As New Jpeg2000Engine()
      Dim fileInfo As Jpeg2000FileInformation = engine.GetFileInformation(fs)

      For i As Integer = 0 To frames.Count - 1
         If (frames(i) >= fileInfo.Frame.GetLength(0)) Then
            Return Nothing
         End If
      Next i

      Dim buffer() As Byte = engine.ExtractFramesMemory(fs, frames)

      '  Clean up
      fs.Close()
      Return buffer
   End Function

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class

public byte[] ExtractFramesMemoryStreamExample(List<int> frames)
   {
      FileStream fs = File.OpenRead(Path.Combine(LEAD_VARS.ImagesDir, "image1.jpx"));

      Jpeg2000Engine engine = new Jpeg2000Engine();
      Jpeg2000FileInformation fileInfo = engine.GetFileInformation(fs);

      for (int i = 0; i < frames.Count; i++)
         if (frames[i] >= fileInfo.Frame.GetLength(0))
            return null;
      byte[] buffer = engine.ExtractFramesMemory(fs, frames);
      // Clean up
      fs.Close();
      return buffer;
   }

static class LEAD_VARS
{
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

Jpeg2000Engine Class
Jpeg2000Engine Members
Overload List
ExtractFramesMemory(String, List)
ExtractFramesMemory
ExtractFramesNativeMemory
AppendFrames
AppendGmlData
FragmentJpxFile Method
ReadBox
ReadFrames
ReadGmlData
Compression Using LEAD and JPEG Formats
File Formats - JPEG And LEAD Compressed
Bitmaps In Memory And In Files
JPEG2000 File Comments
JPEG And LEAD File Comments
Programming with JPEG 2000 Features
JPEG 2000 Boxes