StartFeedLoad(Int32,CodecsLoadByteOrder) Method

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public void StartFeedLoad( 
   int bitsPerPixel,
   CodecsLoadByteOrder order
)

'Declaration

Public Overloads Sub StartFeedLoad( _
   ByVal bitsPerPixel As Integer, _
   ByVal order As CodecsLoadByteOrder _
)

'Usage

Dim instance As RasterCodecs
Dim bitsPerPixel As Integer
Dim order As CodecsLoadByteOrder
 
instance.StartFeedLoad(bitsPerPixel, order)

public void StartFeedLoad( 
   int bitsPerPixel,
   CodecsLoadByteOrder order
)

- (BOOL)startFeedLoad:(NSInteger)bitsPerPixel order:(LTCodecsLoadByteOrder)order error:(NSError **)error

public FeedCallbackThunk startFeedLoad(int bitsPerPixel, CodecsLoadByteOrder order)

 function Leadtools.Codecs.RasterCodecs.StartFeedLoad(Int32,CodecsLoadByteOrder)( 
   bitsPerPixel ,
   order 
)

public:
void StartFeedLoad( 
   int bitsPerPixel,
   CodecsLoadByteOrder order
)

Parameters

bitsPerPixel

Resulting image pixel depth. Valid values are:

Value	Meaning
0	Keep the original file's pixel depth (Do not convert).
1 to 8	The specified bits per pixel in the resulting image.
12	12 bits per pixel in the resulting image.
16	16 bits per pixel in the resulting image.
24	24 bits per pixel in the resulting image.
32	32 bits per pixel in the resulting image.
48	48 bits per pixel in the resulting image.
64	64 bits per pixel in the resulting image.

order

The desired color order. Possible values are:

Value	Meaning
CodecsLoadByteOrder.Rgb	Red, green, and blue color order in memory
CodecsLoadByteOrder.Bgr	Blue, green, and red color order in memory
CodecsLoadByteOrder.Gray	12 or 16-bit grayscale image. 12 and 16-bit grayscale images are only supported in the Document/Medical Imaging editions.
CodecsLoadByteOrder.RgbOrGray	Load the image as red, green, blue OR as a 12 or 16-bit grayscale image. 12 and 16-bit grayscale images are supported in the Document/Medical Imaging editions
CodecsLoadByteOrder.BgrOrGray	Load the image as blue, green, red OR as a 12 or 16-bit grayscale image. 12 and 16-bit grayscale images are supported in the Document/Medical Imaging editions
CodecsLoadByteOrder.Romm	ROMM order. ROMM only supports 24 and 48-bit images
CodecsLoadByteOrder.BgrOrGrayOrRomm	Load the image as red, green, blue OR as a 12 or 16-bit grayscale image OR as ROMM. 12 and 16-bit grayscale images are supported in the Document/Medical Imaging editions only. ROMM only supports 24 and 48-bit color images.

You must call the FeedLoad method to supply buffered data, and you must call StopFeedLoad when the loading is complete.

This file-load process is useful when receiving transmitted images, such as those on the Internet. It works the same way as the Load or LoadAsync methods, except that your code supplies the image data. The file-load process works as follows:

You call the StartFeedLoad method to initialize the file-load process.
You create a buffer, and each time you fill it with information, you call the FeedLoad method, which sends the data to the file-load process just as if the data were being read from a file on disk.
Whenever it has enough data to do so, the file-load process behaves the same as in the Load or LoadAsync methods. It allocates and begins loading the image. It calls your LoadImage event handler, if one is specified, whenever it has enough data in its input buffer.

The file-load process updates information in the RasterImage when it has received enough information to do so. The file-load process will make the first call to your event handler whenever this information is available.
At any time after calling StartFeedLoad, you can call CancelFeedLoad to gracefully abort the feed load operation. This allows you to end the feed load process without throwing an exception.
To end the file-load process, you call the StopFeedLoad method, which cleans up the process, and returns the loaded RasterImage, if successful. If you call this method before supplying the complete file, it will successfully clean up the process, but will throw an exception. You should catch the exception if the load is canceled purposely.

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

This method cannot be used in combination with StartRedirecting.

The CodecsLoadOptions.AllPages property controls whether RasterCodecs will try to load all pages or just the first page if the image data contains multiple pages.

This example will use feed load to load an image from a url

C#
Visual Basic
WinRT C#
WinRT JavaScript
Silverlight C#
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Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.ImageProcessing
Imports Leadtools.ImageProcessing.Color
Imports Leadtools.Drawing
Imports Leadtools.Svg

      
Public Sub FeedLoadExample()
   Dim codecs As RasterCodecs = New RasterCodecs()
   Dim url As String = "https://www.leadtools.com/images/web-header.jpg"
   Dim destFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "FeedLoad.bmp")

   ' Create a WebRequest for the URL
   Dim request As WebRequest = WebRequest.Create(url)
   request.Proxy.Credentials = CredentialCache.DefaultCredentials

   ' reduce the timeout to 20sec
   request.Timeout = 20000

   Dim response As WebResponse = request.GetResponse()
   Try
      Dim strm As Stream = response.GetResponseStream()

      ' Read chunks from the stream and feed load to the image
      codecs.StartFeedLoad(0, CodecsLoadByteOrder.BgrOrGray)

      Const bufferSize As Integer = 1024
      Dim buffer(bufferSize - 1) As Byte

      Dim read As Integer

      Do
         System.Windows.Forms.Application.DoEvents()

         read = strm.Read(buffer, 0, bufferSize)
         Console.WriteLine("Downloading {0} bytes", read)
         If read > 0 Then
            codecs.FeedLoad(buffer, 0, read)
         End If
      Loop While read > 0
   Finally
      response.Close()
   End Try

   Dim image As RasterImage = codecs.StopFeedLoad()

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

   ' Clean up
   codecs.Dispose()
End Sub

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.ImageProcessing;
using Leadtools.ImageProcessing.Color;
using Leadtools.Svg;

      
public void FeedLoadExample()
{
   RasterCodecs codecs = new RasterCodecs();
   string url = @"https://www.leadtools.com/images/page_graphics/leadlogo.png";
   string destFileName = Path.Combine(LEAD_VARS.ImagesDir, "FeedLoad.bmp");

   // Create a WebRequest for the URL
   WebRequest request = WebRequest.Create(url);
   request.Proxy.Credentials = CredentialCache.DefaultCredentials;

   // reduce the timeout to 20sec
   request.Timeout = 20000;

   WebResponse response = request.GetResponse();
   try
   {
      Stream strm = response.GetResponseStream();

      // Read chunks from the stream and feed load to the image
      codecs.StartFeedLoad(0, CodecsLoadByteOrder.BgrOrGray);

      const int bufferSize = 1024;
      byte[] buffer = new byte[bufferSize];

      int read;

      do
      {
         System.Windows.Forms.Application.DoEvents();

         read = strm.Read(buffer, 0, bufferSize);
         Console.WriteLine("Downloading {0} bytes", read);
         if (read > 0)
            codecs.FeedLoad(buffer, 0, read);
      }
      while (read > 0);
   }
   finally
   {
      response.Close();
   }

   RasterImage image = codecs.StopFeedLoad();

   // Save the image to disk
   codecs.Save(image, destFileName, RasterImageFormat.Bmp, 24);
   image.Dispose();

   // Clean up
   codecs.Dispose();
}

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

//RasterCodecsExamples.prototype.FeedLoadExample = function ( ) 
//{
//   Tools.SetLicense ( ) ;
//   with ( Leadtools ) { with ( Leadtools.Codecs ) { 
//   var codecs = new RasterCodecs();

//   var url = "https://www.leadtools.com/images/page_graphics/leadlogo.png";
//   var destFileName = "FeedLoad.bmp";

//   // Create a WebRequest for the URL
//   WebRequest request = WebRequest.Create(url);
//   request.Proxy.Credentials = CredentialCache.DefaultCredentials;

//   WebResponse response = await request.GetResponseAsync();
//   try
//   {
//      Stream strm = response.GetResponseStream();

//      // Read chunks from the stream and feed load to the image
//      codecs.StartFeedLoad(0, CodecsLoadByteOrder.BgrOrGray);

//      const int bufferSize = 1024;
//      byte[] buffer = new byte[bufferSize];

//      int read;

//      do
//      {
//         read = strm.Read(buffer, 0, bufferSize);
//         console.info("Downloading {0} bytes", read);
//         if (read > 0)
//            codecs.FeedLoad(buffer, 0, read);
//      }
//      while (read > 0);
//   }
//   finally
//   {
//      response.Dispose();
//   }

//   RasterImage image = codecs.StopFeedLoad();

//   // Save the image to disk
//   StorageFile saveFile = await Tools.AppLocalFolder.CreateFileAsync(destFileName);
//   await codecs.SaveAsync(image, LeadStreamFactory.Create(saveFile), RasterImageFormat.Bmp, 24);
//   image.Dispose();

//   // Clean up
//   codecs.Dispose();
//}
//

using Leadtools;
using Leadtools.Codecs;
using Leadtools.ImageProcessing;
using Leadtools.ImageProcessing.Color;

      
public async Task FeedLoadExample()
{
   RasterCodecs codecs = new RasterCodecs();
   string url = @"https://www.leadtools.com/images/page_graphics/leadlogo.png";
   string destFileName = @"FeedLoad.bmp";

   // Create a WebRequest for the URL
   WebRequest request = WebRequest.Create(url);
   request.Proxy.Credentials = CredentialCache.DefaultCredentials;

   WebResponse response = await request.GetResponseAsync();
   try
   {
      Stream strm = response.GetResponseStream();

      // Read chunks from the stream and feed load to the image
      codecs.StartFeedLoad(0, CodecsLoadByteOrder.BgrOrGray);

      const int bufferSize = 1024;
      byte[] buffer = new byte[bufferSize];

      int read;

      do
      {
         read = strm.Read(buffer, 0, bufferSize);
         Debug.WriteLine("Downloading {0} bytes", read);
         if (read > 0)
            codecs.FeedLoad(buffer, 0, read);
      }
      while (read > 0);
   }
   finally
   {
      response.Dispose();
   }

   RasterImage image = codecs.StopFeedLoad();

   // Save the image to disk
   StorageFile saveFile = await Tools.AppLocalFolder.CreateFileAsync(destFileName);
   await codecs.SaveAsync(image, LeadStreamFactory.Create(saveFile), RasterImageFormat.Bmp, 24);
   image.Dispose();

   // Clean up
   codecs.Dispose();
}

Target Platforms

Reference

RasterCodecs Class
RasterCodecs Members
Overload List
Loading and Saving Images
Loading and Saving Large TIFF / BigTIFF Files
Speeding Up 1-Bit Documents
Fast File Info