ChangeContrastCommand Class

Summary

Increases or decreases the contrast of the image.

Syntax

Objective-C

C++

Java

public class ChangeContrastCommand : RasterCommand

Public Class ChangeContrastCommand  
   Inherits RasterCommand

@interface LTChangeContrastCommand : LTRasterCommand

public class ChangeContrastCommand extends RasterCommand

public ref class ChangeContrastCommand : public 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.

Example

Runs the ChangeContrastCommand on an image and increases its contrast.

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:\Users\Public\Documents\LEADTOOLS Images"; 
}

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing.Color 
 
Public Sub ChangeContrastCommandExample() 
   Dim codecs As New RasterCodecs() 
   codecs.ThrowExceptionsOnInvalidImages = True 
 
   Dim leadImage As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "ImageProcessingDemo\\Image1.jpg")) 
 
   ' Prepare the command 
   Dim command As ChangeContrastCommand = New ChangeContrastCommand 
   'Increase the contrast  by 25 percent  of the possible range. 
   command.Contrast = 250 
 
   command.Run(leadImage) 
   codecs.Save(leadImage, Path.Combine(LEAD_VARS.ImagesDir, "Result.jpg"), RasterImageFormat.Jpeg, 24) 
 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images" 
End Class

c#[Silverlight C# Example] 
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Examples; 
 
public void ChangeContrastCommandExample(RasterImage image, Stream outStream) 
{ 
   // Prepare the command 
   ChangeContrastCommand command = new ChangeContrastCommand(); 
   //Increase the contrast  by 25 percent  of the possible range. 
   command.Contrast = 250; 
   command.Run(image); 
 
   // Save result image 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24); 
   image.Dispose(); 
} 
vb[Silverlight VB Example] 
Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing.Color 
 
Public Sub ChangeContrastCommandExample(ByVal image As RasterImage, ByVal outStream As Stream) 
   ' Prepare the command 
   Dim command As ChangeContrastCommand = New ChangeContrastCommand() 
   'Increase the contrast  by 25 percent  of the possible range. 
   command.Contrast = 250 
   command.Run(image) 
 
   ' Save result image 
   Dim codecs As RasterCodecs = New RasterCodecs() 
   codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24) 
   image.Dispose() 
End Sub