ReadThumbnail(string,CodecsThumbnailOptions,int) Method

Summary

Creates a thumbnail from the specified image file.

Syntax

Objective-C

C++/CLI

Python

public RasterImage ReadThumbnail( 
   string fileName, 
   CodecsThumbnailOptions options, 
   int pageNumber 
)

- (nullable LTRasterImage *)readThumbnailFromFile:(NSString *)file  
                                          options:(LTCodecsThumbnailOptions *)thumbnailOptions  
                                       pageNumber:(NSInteger)pageNumber  
                                            error:(NSError **)error

public: 
RasterImage^ ReadThumbnail(  
   String^ fileName, 
   CodecsThumbnailOptions options, 
   int pageNumber 
)

def ReadThumbnail(self,fileName,options,pageNumber):

Parameters

fileName
A String containing the name of the file from which the thumbnail image will be created.

options
Options for creating the thumbnail image.

pageNumber
1-based index of the page from which the thumbnail image should be created.

Return Value

The RasterImage object that this method creates.

Remarks

This method will always return a thumbnail image. Depending on the options passed, this method might read the stamp stored inside EXIF, CMP, JFIF and FlashPix files and return that. To read the file stamp only, use ReadStamp.

Example

This example will read a thumbnail from a CMP file

Java

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Svg; 
 
 
public void ReadThumbnailExample() 
{ 
   RasterCodecs codecs = new RasterCodecs(); 
 
   string srcFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"); 
 
   // Create a thumbnail with default options 
   CodecsThumbnailOptions options = CodecsThumbnailOptions.Default; 
   options.LoadStamp = false; 
   RasterImage thumbnail = codecs.ReadThumbnail(srcFileName, options, 1); 
 
   Debug.WriteLine("Thumbnail with default option:"); 
   Debug.WriteLine("  Size: {0} by {1} pixels. Bits/Pixel: {2}", thumbnail.Width, thumbnail.Height, thumbnail.BitsPerPixel); 
   thumbnail.Dispose(); 
 
   // Create a thumbnail with some options 
   options.LoadStamp = false; 
   options.Width = 40; 
   options.Height = 80; 
   options.ForceSize = true; 
   options.MaintainAspectRatio = false; 
   options.BackColor = RasterColor.FromKnownColor(RasterKnownColor.LightBlue); 
   options.BitsPerPixel = 8; 
   options.DitheringMethod = RasterDitheringMethod.None; 
   options.Order = RasterByteOrder.Rgb; 
   options.PaletteFlags = ColorResolutionCommandPaletteFlags.None; 
   options.Resample = false; 
   thumbnail = codecs.ReadThumbnail(srcFileName, options, 1); 
 
   Debug.WriteLine("Thumbnail with set option (size: {0} by {1}, Bits/Pixel: {2}, ForeSize: {3}", 
      options.Width, options.Height, options.BitsPerPixel, options.ForceSize); 
   Debug.WriteLine("  Size: {0} by {1} pixels. Bits/Pixel: {2}", thumbnail.Width, thumbnail.Height, thumbnail.BitsPerPixel); 
   thumbnail.Dispose(); 
 
   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 readThumbnailExample() throws IOException { 
   final String LEAD_VARS_IMAGES_DIR = "C:\\LEADTOOLS23\\Resources\\Images"; 
   RasterCodecs codecs = new RasterCodecs(); 
 
   String srcFileName = combine(LEAD_VARS_IMAGES_DIR, "Image1.cmp"); 
 
   // Create a thumbnail with default options 
   CodecsThumbnailOptions options = CodecsThumbnailOptions.getDefault(); 
   options.setLoadStamp(false); 
   ILeadStream srcFileStream = LeadStreamFactory.create(srcFileName); 
   RasterImage thumbnail = codecs.readThumbnail(srcFileStream, options, 1); 
 
   System.out.println("Thumbnail with default option:"); 
   System.out.println("  Size: " + thumbnail.getWidth() + " by " + thumbnail.getHeight() + " pixels. Bits/Pixel: " 
         + thumbnail.getBitsPerPixel()); 
   thumbnail.dispose(); 
 
   // Create a thumbnail with some options 
   options.setLoadStamp(false); 
   options.setWidth(40); 
   options.setHeight(80); 
   options.setForceSize(true); 
   options.setMaintainAspectRatio(false); 
   options.setBackColor(RasterColor.fromKnownColor(RasterKnownColor.LIGHT_BLUE)); 
   options.setBitsPerPixel(8); 
   options.setDitheringMethod(RasterDitheringMethod.NONE); 
   options.setOrder(RasterByteOrder.RGB); 
   options.setPaletteFlags(ColorResolutionCommandPaletteFlags.NONE); 
   options.setResample(false); 
   thumbnail = codecs.readThumbnail(srcFileStream, options, 1); 
 
   assertTrue("Incorrect dithering method", options.getDitheringMethod().equals(RasterDitheringMethod.NONE)); 
   System.out.println("Correct dithering method was used"); 
 
   System.out.printf("Thumbnail with set option (size: %s by %s, Bits/Pixel: %s, ForeSize: %s%n", 
         options.getWidth(), options.getHeight(), options.getBitsPerPixel(), options.getForceSize()); 
   System.out.printf("  Size: %s by %s pixels. Bits/Pixel: %s%n", thumbnail.getWidth(), thumbnail.getHeight(), 
         thumbnail.getBitsPerPixel()); 
   thumbnail.dispose(); 
 
   srcFileStream.close(); 
   codecs.dispose(); 
}

Requirements

Target Platforms

Reference

Download our FREE evaluation

Help Version 23.0.2024.2.29