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ExtractMessageCommand Class
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Leadtools.ImageProcessing.Effects Namespace : ExtractMessageCommand Class



Extracts a message (text or file) from the image, if the image has an embedded message. This command is available in the Document/Medical Toolkits.

Syntax

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

Example

Run the ExtractMessageCommand on an image by loading an image that has an embedded message and extracts the message from it.

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

   Dim leadImage As RasterImage = codecs.Load(LeadtoolsExamples.Common.ImagesPath.Path + "Master.jpg")

   Dim addmessagecommand As AddMessageCommand = New AddMessageCommand
   addmessagecommand.Message = "LEAD Technologies, Inc."
   ' Add the above message to image in the default position and with the default password.
   addmessagecommand.Run(leadImage)
   ' Prepare the command

   Dim command As ExtractMessageCommand = New ExtractMessageCommand

   ' set password and start properties values same as AddMessageCommand values.
   command.Password = Nothing
   command.Start = New Point(0, 0)
   command.Directory = LeadtoolsExamples.Common.ImagesPath.Path

   ' Extract the message from the image in the default position and with the default password.
   command.Run(leadImage)
   codecs.Save(leadImage, LeadtoolsExamples.Common.ImagesPath.Path + "Result.jpg", RasterImageFormat.Jpeg, 24)


   If (Not (IsNothing(command.Message))) Then
      MessageBox.Show(command.Message, "Extracted Message")
   ElseIf (Not (IsNothing(command.FileName))) Then
      MessageBox.Show(command.FileName, "Extracted File")
   End If

   RasterCodecs.Shutdown()
End Sub
C#Copy Code
public void ExtractMessageCommandExample() 
{ 
   // Load an image 
   RasterCodecs.Startup(); 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.ThrowExceptionsOnInvalidImages = true; 
 
   RasterImage image = codecs.Load(LeadtoolsExamples.Common.ImagesPath.Path + "Result.jpg"); 
 
   // Prepare the command 
   AddMessageCommand addmessageCommand = new AddMessageCommand(); 
   addmessageCommand.Password = null; 
   addmessageCommand.Start = new Point(0, 0); 
   addmessageCommand.Message = "LEAD Technologies, Inc."; 
   // Add the above message to image in the default position and with the default password. 
   addmessageCommand.Run(image); 
 
   // Prepare the command 
   ExtractMessageCommand command = new ExtractMessageCommand(); 
 
   // set password and start properties values same as AddMessageCommand values. 
   command.Password    = null; 
   command.Start       = new Point(0,0); 
   command.Directory   = LeadtoolsExamples.Common.ImagesPath.Path + ""; 
 
   // Extract the message from the image in the default position and with the default password. 
   command.Run(image); 
   codecs.Save(image, LeadtoolsExamples.Common.ImagesPath.Path + "Result.jpg", RasterImageFormat.Jpeg, 24); 
 
   if(command.Message != null && command.Message.Length != 0) 
      MessageBox.Show(command.Message, "Extracted Message"); 
   else  if (command.FileName != null && command.FileName.Length != 0) 
      MessageBox.Show(command.FileName, "Extracted File"); 
 
 
   RasterCodecs.Shutdown(); 
}

Remarks

  • This command is used to extract the message that was added to the image by the AddMessageCommand.
  • Before calling this command, set the password, the starting point, and the directory using the same information used for these when the message was added.
  • This command can extract a message from any type of lossless image format such as bmp, tiff, lossless jpeg, and so forth. If used with lossy format types the message may be corrupted or lost.
  • This method supports 24- and 48-bits images, and 8- and 16-bits grayscale images.
  • Support for 16-bit grayscale and 48-bit color images is available only in the Document/Medical toolkits.
  • This command does not support 32-bit grayscale images.

Inheritance Hierarchy

System.Object
   Leadtools.ImageProcessing.RasterCommand
      Leadtools.ImageProcessing.Effects.ExtractMessageCommand

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