FromHBitmap(IntPtr,IntPtr,IntPtr) Method

Summary

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

Syntax

C++/CLI

Python

public static RasterImage FromHBitmap( 
   IntPtr hdc, 
   IntPtr hbitmap, 
   IntPtr hpalette 
)

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

def FromHBitmap(self,hdc,hbitmap,hpalette):

Parameters

hdc
Handle to the Windows device context responsible for the conversion. The mapping mode of the device context must be MM_TEXT.

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 created Leadtools.RasterImage object.

Remarks

For more information on DDBs, DIBs, GDI, and GDI+ refer to Using DIBs, DDBs, and the Clipboard and 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:\LEADTOOLS22\Resources\Images"; 
}