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GammaCorrectExtendedCommand Class
See Also  Members   Example 



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.

Syntax

Visual Basic (Declaration) 
Public Class GammaCorrectExtendedCommand 
   Inherits RasterCommand
   Implements IRasterCommand 
Visual Basic (Usage)Copy Code
Dim instance As GammaCorrectExtendedCommand
C# 
public class GammaCorrectExtendedCommand : RasterCommand, IRasterCommand 
C++/CLI 
public ref class GammaCorrectExtendedCommand : public RasterCommand, IRasterCommand 

Example

Run the GammaCorrectExtendedCommand on an image.

Visual BasicCopy Code
Public Sub GammaCorrectExtendedCommandExample()
   RasterCodecs.Startup()
   Dim codecs As New RasterCodecs()
   codecs.ThrowExceptionsOnInvalidImages = True

   Dim leadImage As RasterImage = codecs.Load(LeadtoolsExamples.Common.ImagesPath.Path + "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, LeadtoolsExamples.Common.ImagesPath.Path + "Result.jpg", RasterImageFormat.Jpeg, 24)

   RasterCodecs.Shutdown()
End Sub
C#Copy Code
public void GammaCorrectExtendedCommandExample() 
{ 
   // Load an image 
   RasterCodecs.Startup(); 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.ThrowExceptionsOnInvalidImages = true; 
 
   RasterImage image = codecs.Load(LeadtoolsExamples.Common.ImagesPath.Path + "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, LeadtoolsExamples.Common.ImagesPath.Path + "Result.jpg", RasterImageFormat.Jpeg, 24); 
 
   RasterCodecs.Shutdown(); 
}

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;

Inheritance Hierarchy

System.Object
   Leadtools.ImageProcessing.RasterCommand
      Leadtools.ImageProcessing.Color.GammaCorrectExtendedCommand

Requirements

Target Platforms: Microsoft .NET Framework 2.0, Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also