Load(Stream,int) Method

Summary

Loads the specified page from an image stream using default options.

Syntax

Objective-C

C++/CLI

Java

Python

public RasterImage Load( 
   Stream stream, 
   int pageNumber 
)

- (nullable LTRasterImage *)loadStream:(LTLeadStream *)stream  
                            pageNumber:(NSInteger)pageNumber  
                                 error:(NSError **)error

public RasterImage load(ILeadStream stream, int PageNumber)

public: 
RasterImage^ Load(  
   Stream^ stream, 
   int pageNumber 
)

def Load(self,stream,pageNumber):

Parameters

stream
A Stream containing the image data to load.

pageNumber
1-based index to the page number to load.

Return Value

The RasterImage object that this method loads.

Remarks

The stream can point to any supported image file format and bits per pixel, whether compressed or uncompressed.

This method will load a single page from 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 stream.

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 option parameters before calling this method.

Support for 12 and 16-bit grayscale, and 48 and 64-bit color images is only available in the Document/Medical Imaging editions.

For supported formats, refer to Summary of All Supported 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.

Use StartOptimizedLoad to speed up loading or converting multiple pages from the same source file.

Example

This example will query the number of pages from a URI and then load them.

Java

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Svg; 
 
 
public void LoadPagesFromStreamTest() 
{ 
 
   // Create a new RasterCodecs instance 
   using (RasterCodecs rasterCodecs = new RasterCodecs()) 
   { 
      Stream stream = File.OpenRead(Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp")); 
      RasterImageFormat rasterImageFormat = rasterCodecs.GetFormat(stream); 
      int totalPages = rasterCodecs.GetTotalPages(stream); 
 
      // Using extensions in RasterCodecsExtensions 
      // GetInformationAsync is used to get CodecsImageInfo 
      using (ILeadStream outputLeadStream = LeadStream.Factory.FromStream(stream)) 
      { 
 
         //Using GetInformationAsync to obtain the format data as CodecsImageInfo, instead of the internal GetFormatAsync 
         Task<CodecsImageInfo> task = rasterCodecs.GetInformationAsync(outputLeadStream, true); 
         CodecsImageInfo codecsImageInfo = task.Result; 
 
         //Get task data 
         Debug.WriteLine($"Task ID: {task.Id}"); 
         Debug.WriteLine($"Is a Document File: {task.Result.Document.IsDocumentFile}"); 
         Debug.WriteLine($"codecsImageInfo Palette: {codecsImageInfo.GetPalette()}"); 
 
         // Get total pages using TotalPages instead of GetTotalPagesAsync 
         Debug.WriteLine($"Total Pages: {task.Result.TotalPages}"); 
 
      } 
 
      // Get the number of pages 
      int pageCount = rasterCodecs.GetTotalPages(stream); 
      Debug.WriteLine("Number of pages in the file is {0}", pageCount); 
 
      // Load all pages 
      for (int pageNumber = 1; pageNumber <= pageCount; pageNumber++) 
      { 
         using (RasterImage rasterImage = rasterCodecs.Load(stream, pageNumber)) 
         { 
            Debug.WriteLine("Page {0} loaded", pageNumber); 
         } 
      } 
   } 
} 
 
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.*; 
 
 
RasterCodecs rasterCodecs; 
ILeadStream inputStream; 
 
public void loadPagesFromStreamExample() throws IOException { 
   final String LEAD_VARS_IMAGES_DIR = "C:\\LEADTOOLS23\\Resources\\Images"; 
   rasterCodecs = new RasterCodecs(); 
 
   inputStream = LeadStreamFactory.create(combine(LEAD_VARS_IMAGES_DIR, "Image1.cmp")); 
   rasterCodecs.getFormat(inputStream); 
   rasterCodecs.getTotalPages(inputStream); 
 
   // GetInformationAsync is used to get CodecsImageInfo 
   // Using GetInformationAsync to obtain the format data as CodecsImageInfo, 
   // instead of the internal GetFormatAsync 
   rasterCodecs.getInformationAsync(inputStream, true, 1, null); 
} 
 
CodecsGetInformationAsyncCompletedListener codecsGetInformationAsyncCompleted = new CodecsGetInformationAsyncCompletedListener() { 
 
   @Override 
   public void onGetInformationAsyncCompleted(CodecsGetInformationAsyncCompletedEvent e) { 
      CodecsImageInfo task = e.getInfo(); 
      // Get task data 
      System.out.println("Task Name: " + task.getName()); 
      System.out.println("Is a Document File: " + task.getDocument().isDocumentFile()); 
      System.out.println("codecsImageInfo Palette: " + task.getPalette()); 
      // Get total pages using TotalPages instead of GetTotalPagesAsync 
      System.out.println("Total Pages: " + task.getTotalPages()); 
      // Get the number of pages 
      int pageCount = rasterCodecs.getTotalPages(inputStream); 
      System.out.printf("Number of pages in the file is %s%n", pageCount); 
      // Load all pages 
      int i = 0; 
      for (int pageNumber = 1; pageNumber <= pageCount; pageNumber++) { 
         i++; 
         rasterCodecs.load(inputStream, pageNumber); 
         System.out.printf("Page %s loaded%n", pageNumber); 
      } 
      assertTrue("All pages are accounted for", i == pageCount); 
      System.out.println("All pages have been loaded"); 
   } 
 
};

Requirements

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

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Help Version 23.0.2024.2.29