ChangeContrastCommand Class

Summary

Increases or decreases the contrast of the image.

Syntax

Objective-C

C++/CLI

Java

Python

public class ChangeContrastCommand : RasterCommand

@interface LTChangeContrastCommand : LTRasterCommand

public class ChangeContrastCommand 
    extends RasterCommand

public ref class ChangeContrastCommand : public RasterCommand

class ChangeContrastCommand(RasterCommand):

Remarks

This command supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available only in the Document/Medical toolkits.
This command does not support 32-bit grayscale images.
This command supports signed/unsigned data images.

If the image has a LUT and you want to work on the image data, set RasterImage.UseLookupTable to false. Then, after calling the method, reset the UselookupTable property to true, as follows:

rasterImage.UseLookupTable = false; 
Method(rasterImage); 
rasterImage.UseLookupTable = true;

For more information, refer to Changing Brightness and Contrast.

Change Contrast Function - Before

Change Contrast Function - After

View additional platform support for this Change Contrast function.

Example

Runs the ChangeContrastCommand on an image and increases its contrast.

Java

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Color; 
 
 
public void ChangeContrastCommandExample() 
{ 
   // Load an image 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.ThrowExceptionsOnInvalidImages = true; 
 
   RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "ImageProcessingDemo\\Image1.jpg")); 
 
   // Prepare the command 
   ChangeContrastCommand command = new ChangeContrastCommand(); 
   //Increase the contrast  by 25 percent  of the possible range. 
   command.Contrast = 250; 
   command.Run(image); 
   codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "Result.jpg"), RasterImageFormat.Jpeg, 24); 
 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS23\Resources\Images"; 
}

 
import java.io.File; 
import java.io.IOException; 
 
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.imageprocessing.color.*; 
 
 
public void changeContrastCommandExample() { 
 
    final String LEAD_VARS_IMAGES_DIR = "C:\\LEADTOOLS23\\Resources\\Images"; 
    // Load an image 
    RasterCodecs codecs = new RasterCodecs(); 
    codecs.setThrowExceptionsOnInvalidImages(true); 
 
    RasterImage image = codecs.load(combine(LEAD_VARS_IMAGES_DIR, "Image1.jpg")); 
 
    // Prepare the command 
    ChangeContrastCommand command = new ChangeContrastCommand(); 
    // Increase the contrast by 25 percent of the possible range 
    command.setContrast(250); 
    command.run(image); 
    codecs.save(image, combine(LEAD_VARS_IMAGES_DIR, "Result.jpg"), RasterImageFormat.JPEG, 24); 
 
    System.out.println("Command run and image saved to " + combine(LEAD_VARS_IMAGES_DIR, "Result.jpg")); 
    assertTrue(new File(LEAD_VARS_IMAGES_DIR, "Result.jpg").exists()); 
 
}