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Load(Stream,Int64,Int64) Method
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Leadtools.Codecs Namespace > RasterCodecs Class > Load Method : Load(Stream,Int64,Int64) Method




stream
A Stream containing the image data to load.
offset
Offset from the beginning of the stream at which loading should start.
count
Total size of the image file data.
Loads an image file, letting you specify the location of the image data within the stream.

Syntax

Visual Basic (Declaration) 
Overloads Public Function Load( _
   ByVal stream As Stream, _
   ByVal offset As Long, _
   ByVal count As Long _
) As RasterImage
Visual Basic (Usage)Copy Code
Dim instance As RasterCodecs
Dim stream As Stream
Dim offset As Long
Dim count As Long
Dim value As RasterImage
 
value = instance.Load(stream, offset, count)
C# 
public RasterImage Load( 
   Stream stream,
   long offset,
   long count
)
Managed Extensions for C++ 
public: RasterImage Load( 
   Stream* stream,
   long offset,
   long count
)
C++/CLI 
public:
RasterImage Load( 
   Stream^ stream,
   long offset,
   long count
)

Parameters

stream
A Stream containing the image data to load.
offset
Offset from the beginning of the stream at which loading should start.
count
Total size of the image file data.

Return Value

The RasterImage object that this method loads.

Example

Visual BasicCopy Code
RasterCodecs.Load(Stream, long, long)
      Public Sub LoadStreamOffset1Example()
         RasterCodecs.Startup()
         Dim codecs As RasterCodecs = New RasterCodecs()

         Dim srcFileName As String = "C:\Program Files\LEAD Technologies\LEADTOOLS 15\Images\Image1.cmp"
         Dim destFileName As String = "C:\Program Files\LEAD Technologies\LEADTOOLS 15\Images\Image1_LoadStreamOffset1.bmp"

         ' Create a memory stream, add a cutsom header then copy the content of the file
         ' into this stream. After that, load the image from the stream given the offset

         Dim ms As MemoryStream = New MemoryStream()

         ' Add some custom header to the stream (4 bytes)
         Dim headerSize As Integer = 4
         Dim i As Integer = 0
         Do While i < headerSize
            ms.WriteByte(0)
            i += 1
         Loop

         ' Now append the file into this stream
         Dim fs As FileStream = File.OpenRead(srcFileName)

         Const bufferSize As Integer = 1024
         Dim buffer As Byte() = New Byte(bufferSize - 1) {}
         Dim bytesRead As Integer
         Do
            bytesRead = fs.Read(buffer, 0, bufferSize)
            If bytesRead > 0 Then
               ms.Write(buffer, 0, bytesRead)
            End If
         Loop While bytesRead > 0

         fs.Close()

         ' Reset the memory stream position to the beginning
         ms.Position = 0

         ' Now load the image with the offset
         Dim offset As Long = headerSize
         Dim count As Long = ms.Length - headerSize
         Dim image As RasterImage = codecs.Load(ms, offset, count)

         ' Save this image back to disk
         codecs.Save(image, destFileName, RasterImageFormat.Bmp, 24)
         image.Dispose()

         ' Clean up
         codecs.Dispose()
         RasterCodecs.Shutdown()
      End Sub
C#Copy Code
RasterCodecs.Load(Stream, long, long) 
      public void LoadStreamOffset1Example() 
      { 
         RasterCodecs.Startup(); 
         RasterCodecs codecs = new RasterCodecs(); 
 
         string srcFileName = @"C:\Program Files\LEAD Technologies\LEADTOOLS 15\Images\Image1.cmp"; 
         string destFileName = @"C:\Program Files\LEAD Technologies\LEADTOOLS 15\Images\Image1_LoadStreamOffset1.bmp"; 
 
         // Create a memory stream, add a cutsom header then copy the content of the file 
         // into this stream.  After that, load the image from the stream given the offset 
 
         MemoryStream ms = new MemoryStream(); 
 
         // Add some custom header to the stream (4 bytes) 
         int headerSize = 4; 
         for(int i = 0; i < headerSize; i++) 
            ms.WriteByte(0); 
 
         // Now append the file into this stream 
         FileStream fs = File.OpenRead(srcFileName); 
 
         const int bufferSize = 1024; 
         byte[] buffer = new byte[bufferSize]; 
         int bytesRead; 
         do 
         { 
            bytesRead = fs.Read(buffer, 0, bufferSize); 
            if(bytesRead > 0) 
               ms.Write(buffer, 0, bytesRead); 
         } 
         while(bytesRead > 0); 
 
         fs.Close(); 
 
         // Reset the memory stream position to the beginning 
         ms.Position = 0; 
 
         // Now load the image with the offset 
         long offset = headerSize; 
         long count = ms.Length - headerSize; 
         RasterImage image = codecs.Load(ms, offset, count); 
 
         // Save this image back to disk 
         codecs.Save(image, destFileName, RasterImageFormat.Bmp, 24); 
         image.Dispose(); 
 
         // Clean up 
         codecs.Dispose(); 
         RasterCodecs.Shutdown(); 
      }

Remarks

This method can be used to load an image file that is embedded in another stream.

The location of the image is specified as shown in the following simple illustration:

LEADTOOLS will attempt to load corrupted files, so you can see at least a portion of the image. For these images, the load methods succeed, but LoadStatus will return an error code.

This method will load all the pages in a multipage file. The resulting image will have the same bits/pixel and color order value of the image as it was stored in the file.

LEADTOOLS will attempt to load corrupted files, so you can see at least a portion of the image. For these images, the load methods succeed, but LoadStatus will return an error code.

Use the CodecsLoadOptions class to set up other load options parameters before calling this method.

Support for 12 and 16-bit grayscale images is only available in the Document/Medical Imaging editions.

For supported formats, refer to Summary of All Supported Image File Formats.

LEADTOOLS loads all PDF files as Raster PDF uncompressed RasterImageFormat.RasPdf, regardless of the compression and color space used when saving the file.

Requirements

Target Platforms: Microsoft .NET Framework 2.0, Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also