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ChangeToDib Method

Summary

Changes a LEAD RasterImage object to a Windows Device Independent Bitmap (DIB).

Syntax

C++

public IntPtr ChangeToDib( 
   RasterConvertToDibType type 
)

Public Function ChangeToDib( _ 
   ByVal type As Leadtools.RasterConvertToDibType _ 
) As IntPtr

public: 
IntPtr ChangeToDib(  
   Leadtools.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:

a BITMAPFILEHEADER,
a BITMAPV4HEADER (introduced in Windows 95 and Windows NT 4.0),
or a BITMAPV5HEADER (introduced in Windows 2000 and Windows 98),

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

This example loads a RasterImage, changes it to a V5 DIB and writes out the DIB as a bitmap file.

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Core; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Dicom; 
using Leadtools.Drawing; 
using Leadtools.Controls; 
using LeadtoolsExamples.Common; 
using Leadtools.Svg; 
 
[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(ImagesPath.Path, "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(ImagesPath.Path, "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); 
}

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Core 
Imports Leadtools.ImageProcessing.Color 
Imports Leadtools.Controls 
Imports Leadtools.Dicom 
Imports Leadtools.Drawing 
Imports Leadtools.Svg 
 
<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