Run the ColorThresholdCommand on an image.

Visual Basic

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Public Sub ColorThresholdCommandExample()    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 components() As ColorThresholdCommandComponent    ReDim components(2)    components(0) = New ColorThresholdCommandComponent    components(1) = New ColorThresholdCommandComponent    components(2) = New ColorThresholdCommandComponent    components(0).MinimumRange = 128    components(0).MaximumRange = 255    components(0).Flags = 0    components(1).MinimumRange = 128    components(1).MaximumRange = 255    components(1).Flags = 0    components(2).MinimumRange = 128    components(2).MaximumRange = 255    components(2).Flags = 0    Dim command As ColorThresholdCommand = New ColorThresholdCommand(ColorThresholdCommandType.Rgb, components)    'Apply color Threshold effect on the image.    command.Run(leadImage)    codecs.Save(leadImage, LeadtoolsExamples.Common.ImagesPath.Path + "Result.jpg", RasterImageFormat.Jpeg, 24)    RasterCodecs.Shutdown() End Sub

C#

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public void ColorThresholdCommandExample()  {     // 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     ColorThresholdCommandComponent[] Components = new ColorThresholdCommandComponent[3];       Components[0] = new ColorThresholdCommandComponent();     Components[0].MinimumRange = 128;     Components[0].MaximumRange = 255;     Components[0].Flags        = 0;     Components[1] = new ColorThresholdCommandComponent();     Components[1].MinimumRange = 128;     Components[1].MaximumRange = 255;     Components[1].Flags        = 0;     Components[2] = new ColorThresholdCommandComponent();     Components[2].MinimumRange = 128;     Components[2].MaximumRange = 255;     Components[2].Flags        = 0;       ColorThresholdCommand command = new ColorThresholdCommand(ColorThresholdCommandType.Rgb, Components);     //Apply color Threshold effect on the image.     command.Run(image);     codecs.Save(image, LeadtoolsExamples.Common.ImagesPath.Path + "Result.jpg", RasterImageFormat.Jpeg, 24);       RasterCodecs.Shutdown();  }

1. The image is converted to the required color space.
2. For every pixel, the following operations are performed: Each component is compared with the MinimumRange and MaximumRange values of the appropriate ColorThresholdCommandComponent class.
   
   • If it is inside the range, the component is considered to have "passed" the test.
   • If it is outside the range, the component has been rejected". The ColorThresholdCommandFlags.BandReject flag inverts this by making "rejected" components "passed" and viceversa.
3. If ColorThresholdCommandFlags.EffectChannel is set, the components are modified independently. If ColorThresholdCommandFlags.EffectAll has been set, the pixel is rejected by the test if any component is rejected. If the pixel/component is rejected, then:
   
   • If ColorThresholdCommandFlags.SetToMinimum is set, the rejected pixel/component is set to 0.
   • If ColorThresholdCommandFlags.SetToMaximum is set, the rejected pixel/component is set to 255.
   • If ColorThresholdCommandFlags.SetToClamp is set, components less that MinimumRange go to 0 and components greater than MaximumRange go to 255. This would work only with the ColorThresholdCommandFlags.EffectChannel and ColorThresholdCommandFlags.BandBass flags.

• This class works for 1, 2, 3, _ 8,16, 24, 32, 48 and 64-bit color images and can support regions for 24 and 48-bit images. If a 24 or 48-bit image has a region the effect will be applied on the region only.
• One class is used for each color component. The order is considered to be the same as in the xxx Space name. For example, for Rgb Space:
  
  • Components[0] class is used for the Red component.
  • Components[1] class is used for the Green component.
  • Components[2] class is used for the Blue component.
• This command does not support 32-bit grayscale images.
• This command does not support signed images.

System.Object
   Leadtools.ImageProcessing.RasterCommand
      Leadtools.ImageProcessing.Color.ColorThresholdCommand

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

Reference