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HasRegion Property
See Also  Example
Leadtools Namespace > RasterImage Class : HasRegion Property



Determines whether this RasterImage has a region.

Syntax

Visual Basic (Declaration) 
Public ReadOnly Property HasRegion As Boolean
Visual Basic (Usage)Copy Code
Dim instance As RasterImage
Dim value As Boolean
 
value = instance.HasRegion
C# 
public bool HasRegion {get;}
C++/CLI 
public:
property bool HasRegion {
   bool get();
}

Return Value

true if this RasterImage has a region, otherwise; false.

Example

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

   Dim srcFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "Image1.cmp"
   Dim destFileName1 As String = LeadtoolsExamples.Common.ImagesPath.Path + "Image1_InvertRegion.bmp"
   Dim destFileName2 As String = LeadtoolsExamples.Common.ImagesPath.Path + "Image1_InvertNoRegion.bmp"

   ' Load the image
   Dim image As RasterImage = codecs.Load(srcFileName)

   ' The image should have no region
   Console.WriteLine("After loading, HasRegion = {0}", image.HasRegion)
   Debug.Assert((Not image.HasRegion))

   ' Add a region to the image
   Dim rc As Rectangle = New Rectangle(0, 0, image.Width \ 4, image.Height \ 4)
   image.AddEllipseToRegion(Nothing, rc, RasterRegionCombineMode.Set)

   ' The image should have a region now
   Console.WriteLine("After AddEllipseToRegion, HasRegion = {0}", image.HasRegion)
   Debug.Assert(image.HasRegion)

   ' Invert this image and save it to a file
   Dim command As InvertCommand = New InvertCommand()
   command.Run(image)
   codecs.Save(image, destFileName1, RasterImageFormat.Bmp, 24)

   ' Get rid of the region
   image.MakeRegionEmpty()

   ' The image should not have a region now
   Console.WriteLine("After MakeRegionEmpty, HasRegion = {0}", image.HasRegion)
   Debug.Assert((Not image.HasRegion))

   ' Invert again and save it
   command.Run(image)
   codecs.Save(image, destFileName2, RasterImageFormat.Bmp, 24)

   image.Dispose()
   codecs.Dispose()
   RasterCodecs.Shutdown()
End Sub
C#Copy Code
public void RegionExample() 
{ 
   RasterCodecs.Startup(); 
   RasterCodecs codecs = new RasterCodecs(); 
 
   string srcFileName = LeadtoolsExamples.Common.ImagesPath.Path + "Image1.cmp"; 
   string destFileName1 = LeadtoolsExamples.Common.ImagesPath.Path + "Image1_InvertRegion.bmp"; 
   string destFileName2 = LeadtoolsExamples.Common.ImagesPath.Path + "Image1_InvertNoRegion.bmp"; 
 
   // Load the image 
   RasterImage image = codecs.Load(srcFileName); 
 
   // The image should have no region 
   Console.WriteLine("After loading, HasRegion = {0}", image.HasRegion); 
   Debug.Assert(!image.HasRegion); 
 
   // Add a region to the image 
   Rectangle rc = new Rectangle(0, 0, image.Width / 4, image.Height / 4); 
   image.AddEllipseToRegion(null, rc, RasterRegionCombineMode.Set); 
 
   // The image should have a region now 
   Console.WriteLine("After AddEllipseToRegion, HasRegion = {0}", image.HasRegion); 
   Debug.Assert(image.HasRegion); 
 
   // Invert this image and save it to a file 
   InvertCommand command = new InvertCommand(); 
   command.Run(image); 
   codecs.Save(image, destFileName1, RasterImageFormat.Bmp, 24); 
 
   // Get rid of the region 
   image.MakeRegionEmpty(); 
 
   // The image should not have a region now 
   Console.WriteLine("After MakeRegionEmpty, HasRegion = {0}", image.HasRegion); 
   Debug.Assert(!image.HasRegion); 
 
   // Invert again and save it 
   command.Run(image); 
   codecs.Save(image, destFileName2, RasterImageFormat.Bmp, 24); 
 
   image.Dispose(); 
   codecs.Dispose(); 
   RasterCodecs.Shutdown(); 
}

Remarks

When an image has a region, the LEADTOOLS methods that modify the pixel values (for example PosterizeCommand) act on the region, rather than the whole image. In addition, the LEADTOOLS methods that flip, reverse, rotate, shear, or resize an image also transform the region to match the image. For example, if you were to shear the image that had a rectangular region, the region would become a parallelogram.

To remove an image region, use MakeRegionEmpty.

For more information, refer to Working with the Existing Region.

Requirements

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

See Also