LEADTOOLS (Leadtools assembly)
LEAD Technologies, Inc

ChangeToDib Method

Example 





Leadtools Namespace > RasterImage Class : ChangeToDib Method
Type of DIB to create. Possible values are:
Value Meaning
RasterConvertToDibType.BitmapInfoHeader DIB that uses a BITMAPINFOHEADER
RasterConvertToDibType.BitmapV4Header DIB that uses a BITMAPV4HEADER. (Introduced in Windows 95 and Windows NT 4.0)
RasterConvertToDibType.BitmapV5Header DIB that uses a BITMAPV5HEADER (Introduced in Windows 2000 and Windows 98)
Changes a LEAD RasterImage object to a Windows Device Independent Bitmap (DIB). .NET support
Syntax
public IntPtr ChangeToDib( 
   RasterConvertToDibType type
)
'Declaration
 
Public Function ChangeToDib( _
   ByVal type As RasterConvertToDibType _
) As IntPtr
'Usage
 
Dim instance As RasterImage
Dim type As RasterConvertToDibType
Dim value As IntPtr
 
value = instance.ChangeToDib(type)
public IntPtr ChangeToDib( 
   RasterConvertToDibType type
)
 function Leadtools.RasterImage.ChangeToDib( 
   type 
)

public:
IntPtr ChangeToDib( 
   RasterConvertToDibType type
)

Parameters

type
Type of DIB to create. Possible values are:
Value Meaning
RasterConvertToDibType.BitmapInfoHeader DIB that uses a BITMAPINFOHEADER
RasterConvertToDibType.BitmapV4Header DIB that uses a BITMAPV4HEADER. (Introduced in Windows 95 and Windows NT 4.0)
RasterConvertToDibType.BitmapV5Header DIB that uses a BITMAPV5HEADER (Introduced in Windows 2000 and Windows 98)

Return Value

A handle to the device independent bitmap (DIB) this method creates.
Remarks

A DIB consists of one of the following:

followed by a color table and then the bitmap data. The resulting DIB type is determined by the value of the type parameter.

The orientation of the image and color order will depend on how the image was loaded into the RasterImage.

When you no longer need the DIB, you can free it using the Windows GlobalFree function.

This method does not support signed data images. It will throw an exception of type RasterException with code value RasterExceptionCode.SignedDataNotSupported if this RasterImage has a signed data image.

For more information on DDBs and DIBs, refer to Using DIBs, DDBs, and the Clipboard.

Example
  
<DllImport("Kernel32", CharSet:=CharSet.Auto)> _
   Shared Function GlobalSize(ByVal hMem As IntPtr) As IntPtr
   End Function
   <DllImport("Kernel32", CharSet:=CharSet.Auto)> _
   Shared Function GlobalLock(ByVal hMem As IntPtr) As IntPtr
   End Function

   <DllImport("Kernel32", CharSet:=CharSet.Auto)> _
   Shared Function GlobalUnlock(ByVal hMem As IntPtr) As Integer
   End Function

   <DllImport("Kernel32", CharSet:=CharSet.Auto)> _
   Shared Function GlobalFree(ByVal hMem As IntPtr) As IntPtr
   End Function

   <StructLayout(LayoutKind.Sequential, Pack:=1)> _
   Class BITMAPFILEHEADER
      Public bfType As UShort
      Public bfSize As UInteger
      Public bfReserved1 As UShort
      Public bfReserved2 As UShort
      Public bfOffBits As UInteger
   End Class

   <StructLayout(LayoutKind.Sequential, Pack:=1)> _
   Class BITMAPINFOHEADER
      Public biSize As UInteger
      Public biWidth As Integer
      Public biHeight As Integer
      Public biPlanes As UShort
      Public biBitCount As UShort
      Public biCompression As UInteger
      Public biSizeImage As UInteger
      Public biXPelsPerMeter As Integer
      Public biYPelsPerMeter As Integer
      Public biClrUsed As UInteger
      Public biClrImportant As UInteger
   End Class

   <StructLayout(LayoutKind.Sequential, Pack:=1)> _
   Class RGBQUAD
      Public rgbBlue As Byte
      Public rgbGreen As Byte
      Public rgbRed As Byte
      Public rgbReserved As Byte
   End Class


   Public Sub ChangeToDibExample()
      Dim codecs As New RasterCodecs()

      ' Load an image
      Dim image As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"), 24, CodecsLoadByteOrder.BgrOrGray, 1, 1)

      ' Change to DIB
      Dim hdib As IntPtr = image.ChangeToDib(RasterConvertToDibType.BitmapInfoHeader)

      ' Dispose the image since it is unusable now
      image.Dispose()

      ' Clean up
      codecs.Dispose()

      ' Save this DIB to disk as a BMP file

      Dim dibSize As Integer = GlobalSize(hdib).ToInt32()

      Dim bmfh As New BITMAPFILEHEADER()
      bmfh.bfType = &H4D42  ' "BM"
      bmfh.bfSize = CUInt(Marshal.SizeOf(GetType(BITMAPFILEHEADER)) + dibSize)
      bmfh.bfReserved1 = 0
      bmfh.bfReserved2 = 0

      Dim pdib As IntPtr = GlobalLock(hdib)

      Dim bmih As New BITMAPINFOHEADER()
      Marshal.PtrToStructure(pdib, bmih)

      bmfh.bfOffBits = CUInt(Marshal.SizeOf(GetType(BITMAPFILEHEADER)) + bmih.biSize + bmih.biClrUsed * Marshal.SizeOf(GetType(RGBQUAD)))

      Using fs As FileStream = File.Create(Path.Combine(LEAD_VARS.ImagesDir, "Image1_ToDib.bmp"))
         Dim writer As New BinaryWriter(fs)
         writer.Write(bmfh.bfType)
         writer.Write(bmfh.bfSize)
         writer.Write(bmfh.bfReserved1)
         writer.Write(bmfh.bfReserved2)
         writer.Write(bmfh.bfOffBits)

         Dim buffer(1023) As Byte
         Dim offset As Integer = 0
         While (offset < dibSize)
            Dim bytes As Integer = Math.Min(dibSize - offset, buffer.Length)
            Marshal.Copy(New IntPtr(pdib.ToInt64() + offset), buffer, 0, bytes)
            fs.Write(buffer, 0, bytes)

            offset = offset + bytes
         End While
      End Using

      GlobalUnlock(hdib)
      GlobalFree(hdib)
   End Sub

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class
[DllImport("Kernel32", CharSet = CharSet.Auto)]
   static extern IntPtr GlobalSize(IntPtr hMem);
   [DllImport("Kernel32", CharSet = CharSet.Auto)]
   static extern IntPtr GlobalLock(IntPtr hMem);

   [DllImport("Kernel32", CharSet = CharSet.Auto)]
   static extern int GlobalUnlock(IntPtr hMem);

   [DllImport("Kernel32", CharSet = CharSet.Auto)]
   static extern IntPtr GlobalFree(IntPtr hMem);

   [StructLayout(LayoutKind.Sequential, Pack = 1)]
   class BITMAPFILEHEADER
   {
      public ushort bfType;
      public uint bfSize;
      public ushort bfReserved1;
      public ushort bfReserved2;
      public uint bfOffBits;
   }

   [StructLayout(LayoutKind.Sequential, Pack = 1)]
   class BITMAPINFOHEADER
   {
      public uint biSize;
      public int biWidth;
      public int biHeight;
      public ushort biPlanes;
      public ushort biBitCount;
      public uint biCompression;
      public uint biSizeImage;
      public int biXPelsPerMeter;
      public int biYPelsPerMeter;
      public uint biClrUsed;
      public uint biClrImportant;
   }

   [StructLayout(LayoutKind.Sequential, Pack = 1)]
   class RGBQUAD
   {
      public byte rgbBlue;
      public byte rgbGreen;
      public byte rgbRed;
      public byte rgbReserved;
   }


   public void ChangeToDibExample()
   {
      RasterCodecs codecs = new RasterCodecs();

      // Load an image
      RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"), 24, CodecsLoadByteOrder.BgrOrGray, 1, 1);

      // Change to DIB
      IntPtr hdib = image.ChangeToDib(RasterConvertToDibType.BitmapInfoHeader);

      // Dispose the image since it is unusable now
      image.Dispose();

      // Clean up
      codecs.Dispose();

      // Save this DIB to disk as a BMP file

      int dibSize = GlobalSize(hdib).ToInt32();

      BITMAPFILEHEADER bmfh = new BITMAPFILEHEADER();
      bmfh.bfType = 0x4d42; // "BM"
      bmfh.bfSize = (uint)(Marshal.SizeOf(typeof(BITMAPFILEHEADER)) + dibSize);
      bmfh.bfReserved1 = 0;
      bmfh.bfReserved2 = 0;

      IntPtr pdib = GlobalLock(hdib);

      BITMAPINFOHEADER bmih = new BITMAPINFOHEADER();
      Marshal.PtrToStructure(pdib, bmih);

      bmfh.bfOffBits = (uint)(Marshal.SizeOf(typeof(BITMAPFILEHEADER)) + bmih.biSize + bmih.biClrUsed * Marshal.SizeOf(typeof(RGBQUAD)));

      using(FileStream fs = File.Create(Path.Combine(LEAD_VARS.ImagesDir, "Image1_ToDib.bmp")))
      {
         BinaryWriter writer = new BinaryWriter(fs);
         writer.Write(bmfh.bfType);
         writer.Write(bmfh.bfSize);
         writer.Write(bmfh.bfReserved1);
         writer.Write(bmfh.bfReserved2);
         writer.Write(bmfh.bfOffBits);

         byte[] buffer = new byte[1024];
         int offset = 0;
         while(offset < dibSize)
         {
            int bytes = Math.Min(dibSize - offset, buffer.Length);
            Marshal.Copy(new IntPtr(pdib.ToInt64() + offset), buffer, 0, bytes);
            fs.Write(buffer, 0, bytes);

            offset += bytes;
         }
      }

      GlobalUnlock(hdib);
      GlobalFree(hdib);
   }

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

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

See Also

Reference

RasterImage Class
RasterImage Members
FromDib(IntPtr) Method
FromDibArray Method
ToDibArray Method
RasterImageConverter.FromHBitmap
ToDib Method
RasterImageConverter.ToHBitmap
ChangeFromDib Method
RasterImageConverter.ChangeFromHBitmap
RasterImageConverter.ChangeToHBitmap

 

 

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