FromHBitmap(IntPtr,IntPtr) Method

Summary

Creates a new Leadtools.RasterImage from the specified Windows Device-Dependent Bitmap (DDB).

Syntax

C++

public static RasterImage FromHBitmap( 
   IntPtr hbitmap, 
   IntPtr hpalette 
)

Public Overloads Shared Function FromHBitmap( _ 
   ByVal hbitmap As IntPtr, _ 
   ByVal hpalette As IntPtr _ 
) As RasterImage

public: 
static RasterImage^ FromHBitmap(  
   IntPtr hbitmap, 
   IntPtr hpalette 
)

Parameters

hbitmap
Handle to the Windows DDB.

hpalette
Handle to the Windows palette. This value can be IntPtr.Zero if the DDB is dependent on a device that is greater than 8 bits, or if the image will use the system palette.

Return Value

The newly create Leadtools.RasterImage object.

Remarks

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

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

Example

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
 
 
[DllImport("gdi32")] 
private static extern IntPtr CreatePalette(LOGPALETTE256 lplgpl); 
[DllImport("gdi32")] 
private static extern bool DeleteObject(IntPtr hObject); 
 
[StructLayout(LayoutKind.Sequential, Pack = 1)] 
private class LOGPALETTE256 
{ 
   public short palVersion; 
   public short palNumEntries; 
   [MarshalAs(UnmanagedType.ByValArray, SizeConst = 1024)] 
   public byte[] palPalEntry; 
} 
 
public void FromHBitmapExample() 
{ 
   RasterCodecs codecs = new RasterCodecs(); 
 
   // load image as 8-bit 
   using (RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"), 8, CodecsLoadByteOrder.Rgb, 1, 1)) 
   { 
      IntPtr hbitmap = IntPtr.Zero; 
      hbitmap = RasterImageConverter.ToHBitmap(image); 
 
      RasterColor[] colors; 
 
      using (Bitmap btmp = new Bitmap(1, 1)) 
      { 
         using (Graphics g = Graphics.FromImage(btmp)) 
         { 
            colors = RasterImagePainter.GetPaintColors(image, g); 
         } 
      } 
 
      IntPtr hPalette = IntPtr.Zero; 
      if (colors != null && colors.Length <= 256) 
      { 
         LOGPALETTE256 log = new LOGPALETTE256(); 
         log.palVersion = 0x300; 
         log.palNumEntries = (short)colors.Length; 
         log.palPalEntry = new byte[1024]; 
 
         int index = 0; 
         for (int i = 0; i < colors.Length; i++) 
         { 
            log.palPalEntry[index++] = colors[i].R; 
            log.palPalEntry[index++] = colors[i].G; 
            log.palPalEntry[index++] = colors[i].B; 
            log.palPalEntry[index++] = 0; 
         } 
 
         hPalette = CreatePalette(log); 
      } 
 
      using (RasterImage destinationImage = RasterImageConverter.FromHBitmap(hbitmap, hPalette)) 
      { 
         codecs.Save(destinationImage, Path.Combine(LEAD_VARS.ImagesDir, "Image1_FromHBitmap.bmp"), RasterImageFormat.Bmp, 0); 
      } 
 
      if (hPalette != IntPtr.Zero) 
      { 
         DeleteObject(hPalette); 
      } 
 
      DeleteObject(hbitmap); 
   } 
 
   codecs.Dispose(); 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS21\Resources\Images"; 
}

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.Drawing 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Color 
 
<DllImport("gdi32")> 
Private Shared Function CreatePalette(ByVal lplgpl As LOGPALETTE256) As IntPtr 
End Function 
 
<DllImport("gdi32")> 
Private Shared Function DeleteObject(ByVal hObject As IntPtr) As Boolean 
End Function 
 
<StructLayout(LayoutKind.Sequential, Pack:=1)> 
Private Class LOGPALETTE256 
   Public palVersion As Short 
   Public palNumEntries As Short 
   <MarshalAs(UnmanagedType.ByValArray, SizeConst:=1024)> 
   Public palPalEntry() As Byte 
End Class 
 
Public Sub FromHBitmapExample() 
   Dim codecs As New RasterCodecs() 
 
   ' load image as 8-bit 
   Using image As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"), 8, CodecsLoadByteOrder.Rgb, 1, 1) 
      Dim hbitmap As IntPtr = IntPtr.Zero 
      hbitmap = RasterImageConverter.ToHBitmap(image) 
 
      Dim colors() As RasterColor 
 
      Using btmp As New Bitmap(1, 1) 
         Using g As Graphics = Graphics.FromImage(btmp) 
            colors = RasterImagePainter.GetPaintColors(image, g) 
         End Using 
      End Using 
 
      Dim hPalette As IntPtr = IntPtr.Zero 
      If Not IsNothing(colors) AndAlso colors.Length <= 256 Then 
         Dim log As New LOGPALETTE256() 
         log.palVersion = &H300 
         log.palNumEntries = CType(colors.Length, Short) 
         ReDim log.palPalEntry(1023) 
 
         Dim index As Integer = 0 
         For i As Integer = 0 To colors.Length - 1 
            log.palPalEntry(index + 0) = colors(i).R 
            log.palPalEntry(index + 1) = colors(i).G 
            log.palPalEntry(index + 2) = colors(i).B 
            log.palPalEntry(index + 3) = 0 
            index = index + 4 
         Next 
 
         hPalette = CreatePalette(log) 
      End If 
 
      Using destinationImage As RasterImage = RasterImageConverter.FromHBitmap(hbitmap, hPalette) 
         codecs.Save(destinationImage, Path.Combine(LEAD_VARS.ImagesDir, "Image1_FromHBitmap.bmp"), RasterImageFormat.Bmp, 0) 
      End Using 
 
      If hPalette <> IntPtr.Zero Then 
         DeleteObject(hPalette) 
      End If 
 
      DeleteObject(hbitmap) 
   End Using 
 
   codecs.Dispose() 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\LEADTOOLS21\Resources\Images" 
End Class