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ClearNegativePixelsCommand Class
See Also  Members   Example 
Leadtools.ImageProcessing Namespace : ClearNegativePixelsCommand Class



Sets all pixels with negative color values to 0.

Syntax

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

Example

This example sets the Signed flag in the load options, loads a tif file and clears the negative pixels.

Visual BasicCopy Code
Public Sub ClearNegativePixelsCommandExample()
 RasterCodecs.Startup()
 Dim codecs As RasterCodecs = New RasterCodecs()

 Dim srcFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "Image1.cmp"
 Dim destFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "CleanNegativePixelsCommand.tif"

 ' Load the CMP file and convert it to TIF
 Dim image As RasterImage = codecs.Load(srcFileName)
 image.Signed = True
 codecs.Save(image, destFileName, RasterImageFormat.Tif, 24)
 image.Dispose()

 ' Load this image as signed
 codecs.Options.Load.Signed = True

 ' Load the source image from disk
 image = codecs.Load(destFileName)
 Debug.Assert(image.Signed)

 ' Clear the negative pixels and save it it back
 Dim command As ClearNegativePixelsCommand = New ClearNegativePixelsCommand()
 command.Run(image)
 Debug.Assert((Not image.Signed))

 codecs.Save(image, destFileName, RasterImageFormat.Tif, 24)

 ' Clean up
 image.Dispose()
 RasterCodecs.Shutdown()
      End Sub
C#Copy Code
public void ClearNegativePixelsCommandExample() 
{ 
   RasterCodecs.Startup(); 
   RasterCodecs codecs = new RasterCodecs(); 
 
   string srcFileName = LeadtoolsExamples.Common.ImagesPath.Path + "Image1.cmp"; 
   string destFileName = LeadtoolsExamples.Common.ImagesPath.Path + "CleanNegativePixelsCommand.tif"; 
 
   // Load the CMP file and convert it to TIF 
   RasterImage image = codecs.Load(srcFileName); 
   image.Signed = true; 
   codecs.Save(image, destFileName, RasterImageFormat.Tif, 24); 
   image.Dispose(); 
 
   // Load this image as signed 
   codecs.Options.Load.Signed = true; 
 
   // Load the source image from disk 
   image = codecs.Load(destFileName); 
   Debug.Assert(image.Signed); 
 
   // Clear the negative pixels and save it it back 
   ClearNegativePixelsCommand command = new ClearNegativePixelsCommand(); 
   command.Run(image); 
   Debug.Assert(!image.Signed); 
 
   codecs.Save(image, destFileName, RasterImageFormat.Tif, 24); 
 
   // Clean up 
   image.Dispose(); 
   RasterCodecs.Shutdown(); 
}

Remarks

If CodecsLoadOptions.Signed is true when a file is loaded, the image may contain negative pixel values and LEADTOOLS will paint/process the image incorrectly. In order to use this image correctly, you must user ClearNegativePixelsCommand. If the CodecsLoadOptions.Signed property is false, all negative pixels are cleared internally, during the load process.

Since some TIFF files are saved with negative values for pixel colors, you should use ClearNegativePixelsCommand if, after loading an image, RasterImage.Signed is true. ClearNegativePixelsCommand does nothing if RasterImage.IsSigned is false.

Programming tip: use ClearNegativePixelsCommand right after loading the image from file.

For more information, refer to Introduction to Image Processing With LEADTOOLS.

Inheritance Hierarchy

System.Object
   Leadtools.ImageProcessing.RasterCommand
      Leadtools.ImageProcessing.ClearNegativePixelsCommand

Requirements

Target Platforms: Microsoft .NET Framework 3.0, Windows XP, Windows Server 2003 family, Windows Server 2008 family

See Also