ConvertToRegionHandle Method

Visual Basic
C#
WinRT C#
WinRT JavaScript
C++

public static IntPtr ConvertToRegionHandle( 
   RasterRegion region,
   RasterRegionXForm xform
)

'Declaration
 
Public Shared Function ConvertToRegionHandle( _
   ByVal region As RasterRegion, _
   ByVal xform As RasterRegionXForm _
) As IntPtr

'Usage
 
Dim region As RasterRegion
Dim xform As RasterRegionXForm
Dim value As IntPtr
 
value = RasterRegionConverter.ConvertToRegionHandle(region, xform)

public static IntPtr ConvertToRegionHandle( 
   RasterRegion region,
   RasterRegionXForm xform
)

 function Leadtools.Drawing.RasterRegionConverter.ConvertToRegionHandle( 
   region ,
   xform 
)

public:
static IntPtr ConvertToRegionHandle( 
   RasterRegion^ region,
   RasterRegionXForm^ xform
)

Parameters

region: The source LEADTOOLS region. This parameter cannot be null (Nothing in Visual Basic).
xform: Leadtools.RasterRegionXForm object that LEADTOOLS uses to translate between display coordinates and image coordinates.

Return Value

The GDI HRGN object this method creates. You must delete this object after using it using the Windows DeleteObject API.

The LEADTOOLS Leadtools.RasterRegion class provides a platform independent representation of an area of interest in a Leadtools.RasterImage that can be used in any platform supported by LEADTOOLS such as GDI, GDI+, WPF and Silverlight. Use this class To convert a LEADTOOLS Leadtools.RasterRegion object to/from a GDI HRGN and System.Drawing (GDI+) System.Drawing.Region object.

For more information refer to RasterImage and GDI/GDI+.

Visual Basic
C#
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

' Windows API to use in this example
<DllImport("Gdi32")> _
Private Shared Function CreateEllipticRgn(ByVal nLeftRect As Integer, ByVal nTopRect As Integer, ByVal nRightRect As Integer, ByVal nBottomRect As Integer) As IntPtr
End Function
<DllImport("Gdi32")> _
Private Shared Function DeleteObject(ByVal hObject As IntPtr) As Integer
End Function
<DllImport("Gdi32")> _
Private Shared Function OffsetRgn(ByVal hrgn As IntPtr, ByVal nXOffset As Integer, ByVal nYOffset As Integer) As Integer
End Function

Public Sub RasterRegionHandleExample()
   ' Load an image 
   Dim srcFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "Image1.cmp"
   Dim dstFileName1 As String = LeadtoolsExamples.Common.ImagesPath.Path + "Image1_Ellipse.jpg"
   Dim dstFileName2 As String = LeadtoolsExamples.Common.ImagesPath.Path + "Image1_EllipseTranslated.jpg"

   Dim codecs As New RasterCodecs()

   Dim image As RasterImage = codecs.Load(srcFileName)

   ' We will add an ellipse region to the image

   ' Using GDI, create an elliptical region
   Dim gdiRegion As IntPtr = CreateEllipticRgn(100, 200, 100 + 400, 200 + 300)

   ' Create a RasterRegion from this region
   Using region As RasterRegion = RasterRegionConverter.ConvertFromRegionHandle(gdiRegion)
      ' Add this region to the image
      image.SetRegion(Nothing, region, RasterRegionCombineMode.Set)
   End Using

   DeleteObject(gdiRegion)

   ' Fill the image with a color
   Dim cmd As New FillCommand(RasterColor.FromKnownColor(RasterKnownColor.Red))
   cmd.Run(image)

   ' Save it
   codecs.Save(image, dstFileName1, RasterImageFormat.Jpeg, 24)

   ' Now get the GDI+ region from the image
   Using region As RasterRegion = image.GetRegion(Nothing)
      ' Convert it to GDI+
      gdiRegion = RasterRegionConverter.ConvertToRegionHandle(region, Nothing)
   End Using

   ' Move the region 100 pixels to the right and bottom
   OffsetRgn(gdiRegion, 100, 100)

   ' Re-set it into the image, fill again and save
   ' Create a RasterRegion from this region
   Using region As RasterRegion = RasterRegionConverter.ConvertFromRegionHandle(gdiRegion)
      ' Add this region to the image
      image.SetRegion(Nothing, region, RasterRegionCombineMode.Set)
   End Using

   DeleteObject(gdiRegion)

   ' Fill the image with a color
   cmd = New FillCommand(RasterColor.FromKnownColor(RasterKnownColor.Yellow))
   cmd.Run(image)

   ' Save it
   codecs.Save(image, dstFileName2, RasterImageFormat.Jpeg, 24)

   image.Dispose()

   codecs.Dispose()
End Sub

// Windows API to use in this example
   [DllImport("Gdi32")]
   private static extern IntPtr CreateEllipticRgn(int nLeftRect, int nTopRect, int nRightRect, int nBottomRect);
   [DllImport("Gdi32")]
   private static extern int DeleteObject(IntPtr hObject);
   [DllImport("Gdi32")]
   private static extern int OffsetRgn(IntPtr hrgn, int nXOffset, int nYOffset);

   public void RasterRegionHandleExample()
   {
      // Load an image 
      string srcFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp");
      string dstFileName1 = Path.Combine(LEAD_VARS.ImagesDir, "Image1_Ellipse.jpg");
      string dstFileName2 = Path.Combine(LEAD_VARS.ImagesDir, "Image1_EllipseTranslated.jpg");

      RasterCodecs codecs = new RasterCodecs();

      RasterImage image = codecs.Load(srcFileName);

      // We will add an ellipse region to the image

      // Using GDI, create an elliptical region
      IntPtr gdiRegion = CreateEllipticRgn(100, 200, 100 + 400, 200 + 300);

      // Create a RasterRegion from this region
      using(RasterRegion region = RasterRegionConverter.ConvertFromRegionHandle(gdiRegion))
      {
         // Add this region to the image
         image.SetRegion(null, region, RasterRegionCombineMode.Set);
      }

      DeleteObject(gdiRegion);

      // Fill the image with a color
      FillCommand cmd = new FillCommand(RasterColor.FromKnownColor(RasterKnownColor.Red));
      cmd.Run(image);

      // Save it
      codecs.Save(image, dstFileName1, RasterImageFormat.Jpeg, 24);

      // Now get the GDI+ region from the image
      using(RasterRegion region = image.GetRegion(null))
      {
         // Convert it to GDI+
         gdiRegion = RasterRegionConverter.ConvertToRegionHandle(region, null);
      }

      // Move the region 100 pixels to the right and bottom
      OffsetRgn(gdiRegion, 100, 100);

      // Re-set it into the image, fill again and save
      // Create a RasterRegion from this region
      using(RasterRegion region = RasterRegionConverter.ConvertFromRegionHandle(gdiRegion))
      {
         // Add this region to the image
         image.SetRegion(null, region, RasterRegionCombineMode.Set);
      }

      DeleteObject(gdiRegion);

      // Fill the image with a color
      cmd = new FillCommand(RasterColor.FromKnownColor(RasterKnownColor.Yellow));
      cmd.Run(image);

      // Save it
      codecs.Save(image, dstFileName2, RasterImageFormat.Jpeg, 24);

      image.Dispose();

      codecs.Dispose();
   }

static class LEAD_VARS
{
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

RasterRegionConverter Class
RasterRegionConverter Members