GammaCorrectExtendedCommand Class

Adjusts the intensity of colors in an image by changing the gamma constant that is used to map the intensity values. Either of two different color spaces can be specified.

Object Model

Syntax

Visual Basic
C#
WinRT C#
WinRT JavaScript
C++

public class GammaCorrectExtendedCommand : Leadtools.ImageProcessing.RasterCommand, Leadtools.ImageProcessing.IRasterCommand

'Declaration
 
Public Class GammaCorrectExtendedCommand 
   Inherits Leadtools.ImageProcessing.RasterCommand
   Implements Leadtools.ImageProcessing.IRasterCommand

'Usage
 
Dim instance As GammaCorrectExtendedCommand

public sealed class GammaCorrectExtendedCommand : Leadtools.ImageProcessing.IRasterCommand

function Leadtools.ImageProcessing.Color.GammaCorrectExtendedCommand()

public ref class GammaCorrectExtendedCommand : public Leadtools.ImageProcessing.RasterCommand, Leadtools.ImageProcessing.IRasterCommand

Remarks

This command is like the GammaCorrectCommand method, but has been extended to allow the specification of the colorspace to be used.
Intensity values ideally follow a logarithmic progression, because the eye perceives changes in intensity as being equal when the ratio of change is equal. For example, we would see a change from 0.1 to 0.2 as being equal to a change from 0.2 to 0.4.
Gamma is a standard constant that is used to calculate the progression. For most CRTs the gamma constant is in the range of 2.2 to 2.5.
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.

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;

Example

Visual Basic
C#
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Public Sub GammaCorrectExtendedCommandExample()
   Dim codecs As New RasterCodecs()
   codecs.ThrowExceptionsOnInvalidImages = True

   Dim leadImage As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Master.jpg"))

   ' Prepare the command
   Dim command As New GammaCorrectExtendedCommand

   ' Apply gamma effect on image using the YUV color space and gamma value of 2.50
   command.Gamma = 250
   command.Type = GammaCorrectExtendedCommandType.YuvSpace
   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

public void GammaCorrectExtendedCommandExample()
   {
      // Load an image
      RasterCodecs codecs = new RasterCodecs();
      codecs.ThrowExceptionsOnInvalidImages = true;

      RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Master.jpg"));

      // Prepare the command
      GammaCorrectExtendedCommand command = new GammaCorrectExtendedCommand();

      // Apply gamma effect on image using the YUV color space and gamma value of 2.50
      command.Gamma = 250;
      command.Type = GammaCorrectExtendedCommandType.YuvSpace;
      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";
}

[TestMethod]
public async Task GammaCorrectExtendedCommandExample()
{
   // Load an image
   RasterCodecs codecs = new RasterCodecs();
   codecs.ThrowExceptionsOnInvalidImages = true;
   // Load the image
   string srcFileName = @"Assets\Image1.cmp";
   StorageFile loadFile = await Tools.AppInstallFolder.GetFileAsync(srcFileName);
   RasterImage image = await codecs.LoadAsync(LeadStreamFactory.Create(loadFile));

   // Prepare the command
   GammaCorrectExtendedCommand command = new GammaCorrectExtendedCommand();

   // Apply gamma effect on image using the YUV color space and gamma value of 2.50
   command.Gamma = 250;
   command.Type = GammaCorrectExtendedCommandType.YuvSpace;
   command.Run(image);

   string destFileName = @"result.jpg";
   StorageFile saveFile = await Tools.AppLocalFolder.CreateFileAsync(destFileName);
   await codecs.SaveAsync(image, LeadStreamFactory.Create(saveFile), RasterImageFormat.Jpeg, 0);
}

public void GammaCorrectExtendedCommandExample(RasterImage image, Stream outStream)
{
   // Prepare the command
   GammaCorrectExtendedCommand command = new GammaCorrectExtendedCommand();
   // Apply gamma effect on image using the YUV color space and gamma value of 2.50
   command.Gamma = 250;
   command.Type = GammaCorrectExtendedCommandType.YuvSpace;
   command.Run(image);

   // Save result image
   RasterCodecs codecs = new RasterCodecs();
   codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24);
   image.Dispose();
}

Public Sub GammaCorrectExtendedCommandExample(ByVal image As RasterImage, ByVal outStream As Stream)
   ' Prepare the command
   Dim command As GammaCorrectExtendedCommand = New GammaCorrectExtendedCommand()
   ' Apply gamma effect on image using the YUV color space and gamma value of 2.50
   command.Gamma = 250
   command.Type = GammaCorrectExtendedCommandType.YuvSpace
   command.Run(image)

   ' Save result image
   Dim codecs As RasterCodecs = New RasterCodecs()
   codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24)
   image.Dispose()
End Sub

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference