FeedLoad(byte[],int,int) Method

Summary

Supplies image data to the file-load process from a buffer that you provide.

Syntax

C++/CLI

Java

Python

public void FeedLoad( 
   byte[] data, 
   int offset, 
   int length 
)

public void feedLoad(byte data[], int offset, int length)

public: 
void FeedLoad(  
   array<byte>^ data, 
   int offset, 
   int length 
)

def FeedLoad(self,data,offset,length):

Parameters

data
The image file data.

offset
Offset from the beginning of the buffer to where the image data starts.

length
Total size (in bytes) of the image data.

Remarks

Use this method with the StartFeedLoad and StopFeedLoad methods.

For a description of how the methods relate to each other, refer to StartFeedLoad.

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.

Example

Java

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Svg; 
 
 
public void FeedLoadExample() 
{ 
   RasterCodecs codecs = new RasterCodecs(); 
 
   codecs.CancelFeedLoad(); 
 
   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); 
         Debug.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:\LEADTOOLS23\Resources\Images"; 
}

 
import java.io.*; 
import java.net.*; 
import java.nio.file.Paths; 
import java.util.*; 
import java.time.Instant; 
import java.time.Duration; 
 
import org.junit.*; 
import org.junit.runner.JUnitCore; 
import org.junit.runner.Result; 
import org.junit.runner.notification.Failure; 
import static org.junit.Assert.*; 
 
import leadtools.*; 
import leadtools.codecs.*; 
import leadtools.codecs.RasterCodecs.FeedCallbackThunk; 
import leadtools.drawing.internal.*; 
import leadtools.imageprocessing.*; 
import leadtools.imageprocessing.color.ChangeIntensityCommand; 
import leadtools.svg.*; 
 
 
public void feedLoadExample() throws IOException { 
   final String LEAD_VARS_IMAGES_DIR = "C:\\LEADTOOLS23\\Resources\\Images"; 
   RasterCodecs codecs = new RasterCodecs(); 
 
   URL url = new URL("https://www.leadtools.com/images/page_graphics/leadlogo.png"); 
   String destFileName = combine(LEAD_VARS_IMAGES_DIR, "FeedLoad.bmp"); 
 
   // Create a WebRequest for the URL 
   HttpURLConnection con = (HttpURLConnection) url.openConnection(); 
   con.setRequestMethod("GET"); 
   con.setDefaultUseCaches(true); 
   // reduce the timeout to 20sec 
   con.setConnectTimeout(20000); 
   con.setReadTimeout(20000); 
 
   con.getResponseCode(); 
   FeedCallbackThunk feedLoad; 
   try { 
      InputStream requestInput = con.getInputStream(); 
 
      // Read chunks from the stream and feed load to the image 
      feedLoad = codecs.startFeedLoad(0, CodecsLoadByteOrder.BGR_OR_GRAY); 
 
      final int bufferSize = 1024; 
      byte[] buffer = new byte[bufferSize]; 
 
      int read; 
      do { 
         read = requestInput.read(buffer, 0, bufferSize); 
         System.out.println("Downloading " + read + " bytes"); 
         if (read > 0) 
            feedLoad.feedLoad(buffer, 0, read); 
      } while (read > 0); 
      requestInput.close(); 
   } finally { 
      con.disconnect(); 
   } 
 
   RasterImage image = feedLoad.stopFeedLoad(); 
 
   // Save the image to disk 
   codecs.save(image, destFileName, RasterImageFormat.BMP, 24); 
   assertTrue("Image unsuccessfully saved", (new File(destFileName)).exists()); 
   System.out.println("Saved image at" + destFileName); 
 
   // Clean up 
   image.dispose(); 
   codecs.dispose(); 
}