ExtractFramesNativeMemory(Stream,List<Int32>) Method

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

Syntax

public RasterNativeBuffer ExtractFramesNativeMemory( 
   Stream stream,
   List<int> frames
)

public:
RasterNativeBuffer ExtractFramesNativeMemory( 
   Stream^ stream,
   List<int>^ frames
)

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

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

Parameters

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

Return Value

A Leadtools.RasterNativeBuffer object that contains a JPEG 2000 file with only the extracted frames.

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#

Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.Jpeg2000

Private Function ExtractFramesNativeMemoryStreamExample(ByVal frames As List(Of Integer)) As RasterNativeBuffer
   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 RasterNativeBuffer.Empty
      End If
   Next i
   Dim buffer As RasterNativeBuffer = engine.ExtractFramesNativeMemory(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

using Leadtools;
using Leadtools.Codecs;
using Leadtools.Jpeg2000;

public RasterNativeBuffer ExtractFramesNativeMemoryStreamExample(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 RasterNativeBuffer.Empty;
   RasterNativeBuffer buffer = engine.ExtractFramesNativeMemory(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

Reference

Jpeg2000Engine Class
Jpeg2000Engine Members
Overload List
AppendFrames
AppendGmlData
ExtractFrames Method
ExtractFramesMemory
ExtractFramesNativeMemory(String, List)
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