看不懂,请高手指点.(我只知道这是负责扫描的类,请帮忙找出图像回传的代码段)

GdiPlusLib.cs

using System;
using System.IO;
using System.Collections;
using System.Runtime.InteropServices;
using System.Drawing;
using System.Drawing.Imaging;
using System.Windows.Forms;

namespace GdiPlusLib
{
public class Gdip
 {
 private static ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();

 private static bool GetCodecClsid( string filename, out Guid clsid )
  {
  clsid = Guid.Empty;
  string ext = Path.GetExtension( filename );
  if( ext == null )
   return false;
  ext = "*" + ext.ToUpper();
  foreach( ImageCodecInfo codec in codecs )
   {
   if( codec.FilenameExtension.IndexOf( ext ) >= 0 )
    {
    clsid = codec.Clsid;
    return true;
    }
   }
  return false;
  }

 public static bool SaveDIBAs( string picname, IntPtr bminfo, IntPtr pixdat )
  {
  SaveFileDialog sd = new SaveFileDialog();

  sd.FileName = picname;
  sd.Title = "Save bitmap as...";
  sd.Filter = "Bitmap file (*.bmp)|*.bmp|TIFF file (*.tif)|*.tif|JPEG file (*.jpg)|*.jpg|PNG file (*.png)|*.png|GIF file (*.gif)|*.gif|All

files (*.*)|*.*";
  sd.FilterIndex = 1;
  if( sd.ShowDialog() != DialogResult.OK )
   return false;

  Guid clsid;
  if( ! GetCodecClsid( sd.FileName, out clsid ) )
   {
   MessageBox.Show( "Unknown picture format for extension " + Path.GetExtension( sd.FileName ),
       "Image Codec", MessageBoxButtons.OK, MessageBoxIcon.Information );
   return false;
   }
  
  IntPtr img = IntPtr.Zero;
  int st = GdipCreateBitmapFromGdiDib( bminfo, pixdat, ref img );
  if( (st != 0) || (img == IntPtr.Zero) )
   return false;

  st = GdipSaveImageToFile( img, sd.FileName, ref clsid, IntPtr.Zero );
  GdipDisposeImage( img );
  return st == 0;
  }

  [DllImport("gdiplus.dll", ExactSpelling=true)]
 internal static extern int GdipCreateBitmapFromGdiDib( IntPtr bminfo, IntPtr pixdat, ref IntPtr image );

  [DllImport("gdiplus.dll", ExactSpelling=true, CharSet=CharSet.Unicode)]
 internal static extern int GdipSaveImageToFile( IntPtr image, string filename, [In] ref Guid clsid, IntPtr encparams );

  [DllImport("gdiplus.dll", ExactSpelling=true)]
 internal static extern int GdipDisposeImage( IntPtr image );

 }
 
} // namespace GdiPlusLib

TwainDefs.cs

using System;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace TwainLib
{

public class TwProtocol
 {         // TWON_PROTOCOL...
 public const short Major = 1;
 public const short Minor = 9;
 }

 [Flags]
internal enum TwDG : short
 {         // DG_.....
 Control   = 0x0001,
 Image   = 0x0002,
 Audio   = 0x0004
 }

internal enum TwDAT : short
 {         // DAT_....
 Null   = 0x0000,
 Capability  = 0x0001,
 Event   = 0x0002,
 Identity  = 0x0003,
 Parent   = 0x0004,
 PendingXfers = 0x0005,
 SetupMemXfer = 0x0006,
 SetupFileXfer = 0x0007,
 Status   = 0x0008,
 UserInterface = 0x0009,
 XferGroup  = 0x000a,
 TwunkIdentity = 0x000b,
 CustomDSData = 0x000c,
 DeviceEvent  = 0x000d,
 FileSystem  = 0x000e,
 PassThru  = 0x000f,

 ImageInfo  = 0x0101,
 ImageLayout  = 0x0102,
 ImageMemXfer = 0x0103,
 ImageNativeXfer = 0x0104,
 ImageFileXfer = 0x0105,
 CieColor  = 0x0106,
 GrayResponse = 0x0107,
 RGBResponse  = 0x0108,
 JpegCompression = 0x0109,
 Palette8  = 0x010a,
 ExtImageInfo = 0x010b,

 SetupFileXfer2 = 0x0301
 }

internal enum TwMSG : short
 {         // MSG_.....
 Null   = 0x0000,
 Get    = 0x0001,
 GetCurrent  = 0x0002,
 GetDefault  = 0x0003,
 GetFirst  = 0x0004,
 GetNext   = 0x0005,
 Set    = 0x0006,
 Reset   = 0x0007,
 QuerySupport = 0x0008,

 XFerReady  = 0x0101,
 CloseDSReq  = 0x0102,
 CloseDSOK  = 0x0103,
 DeviceEvent  = 0x0104,

 CheckStatus  = 0x0201,

 OpenDSM   = 0x0301,
 CloseDSM  = 0x0302,

 OpenDS   = 0x0401,
 CloseDS   = 0x0402,
 UserSelect  = 0x0403,

 DisableDS  = 0x0501,
 EnableDS  = 0x0502,
 EnableDSUIOnly = 0x0503,

 ProcessEvent = 0x0601,

 EndXfer   = 0x0701,
 StopFeeder  = 0x0702,

 ChangeDirectory = 0x0801,
 CreateDirectory = 0x0802,
 Delete   = 0x0803,
 FormatMedia  = 0x0804,
 GetClose  = 0x0805,
 GetFirstFile = 0x0806,
 GetInfo   = 0x0807,
 GetNextFile  = 0x0808,
 Rename   = 0x0809,
 Copy   = 0x080A,
 AutoCaptureDir = 0x080B,

 PassThru  = 0x0901
 }

internal enum TwRC : short
 {         // TWRC_....
 Success    = 0x0000,
 Failure    = 0x0001,
 CheckStatus   = 0x0002,
 Cancel    = 0x0003,
 DSEvent    = 0x0004,
 NotDSEvent   = 0x0005,
 XferDone   = 0x0006,
 EndOfList   = 0x0007,
 InfoNotSupported = 0x0008,
 DataNotAvailable = 0x0009
 }

internal enum TwCC : short
 {         // TWCC_....
 Success    = 0x0000,
 Bummer    = 0x0001,
 LowMemory   = 0x0002,
 NoDS    = 0x0003,
 MaxConnections  = 0x0004,
 OperationError  = 0x0005,
 BadCap    = 0x0006,
 BadProtocol   = 0x0009,
 BadValue   = 0x000a,
 SeqError   = 0x000b,
 BadDest    = 0x000c,
 CapUnsupported  = 0x000d,
 CapBadOperation  = 0x000e,
 CapSeqError   = 0x000f,
 Denied    = 0x0010,
 FileExists   = 0x0011,
 FileNotFound  = 0x0012,
 NotEmpty   = 0x0013,
 PaperJam   = 0x0014,
 PaperDoubleFeed  = 0x0015,
 FileWriteError  = 0x0016,
 CheckDeviceOnline = 0x0017
 }

internal enum TwOn : short
 {         // TWON_....
 Array   = 0x0003,
 Enum   = 0x0004,
 One    = 0x0005,
 Range   = 0x0006,
 DontCare  = -1
 }

internal enum TwType : short
 {         // TWTY_....
 Int8   = 0x0000,
 Int16   = 0x0001,
 Int32   = 0x0002,
 UInt8   = 0x0003,
 UInt16   = 0x0004,
 UInt32   = 0x0005,
 Bool   = 0x0006,
 Fix32   = 0x0007,
 Frame   = 0x0008,
 Str32   = 0x0009,
 Str64   = 0x000a,
 Str128   = 0x000b,
 Str255   = 0x000c,
 Str1024   = 0x000d,
 Str512   = 0x000e
 }

internal enum TwCap : short
 {
 XferCount  = 0x0001,   // CAP_XFERCOUNT
 ICompression = 0x0100,   // ICAP_...
 IPixelType  = 0x0101,
 IUnits   = 0x0102,
 IXferMech  = 0x0103
 }

// ------------------- STRUCTS --------------------------------------------

 [StructLayout(LayoutKind.Sequential, Pack=2, CharSet=CharSet.Ansi)]
internal class TwIdentity
 {         // TW_IDENTITY
 public IntPtr  Id;
 public TwVersion Version;
 public short  ProtocolMajor;
 public short  ProtocolMinor;
 public int   SupportedGroups;
  [MarshalAs(UnmanagedType.ByValTStr, SizeConst=34)]
 public string  Manufacturer;
  [MarshalAs(UnmanagedType.ByValTStr, SizeConst=34)]
 public string  ProductFamily;
  [MarshalAs(UnmanagedType.ByValTStr, SizeConst=34)]
 public string  ProductName;
 }

 [StructLayout(LayoutKind.Sequential, Pack=2, CharSet=CharSet.Ansi)]
internal struct TwVersion
 {         // TW_VERSION
 public short  MajorNum;
 public short  MinorNum;
 public short  Language;
 public short  Country;
  [MarshalAs(UnmanagedType.ByValTStr, SizeConst=34)]
 public string  Info;
 }

 [StructLayout(LayoutKind.Sequential, Pack=2)]
internal class TwUserInterface
 {         // TW_USERINTERFACE
 public short  ShowUI;    // bool is strictly 32 bit, so use short
 public short  ModalUI;
 public IntPtr  ParentHand;
 }

 [StructLayout(LayoutKind.Sequential, Pack=2)]
internal class TwStatus
 {         // TW_STATUS
 public short  ConditionCode;  // TwCC
 public short  Reserved;
 }

 [StructLayout(LayoutKind.Sequential, Pack=2)]
internal struct TwEvent
 {         // TW_EVENT
 public IntPtr  EventPtr;
 public short  Message;
 }

 [StructLayout(LayoutKind.Sequential, Pack=2)]
internal class TwImageInfo
 {         // TW_IMAGEINFO
 public int   XResolution;
 public int   YResolution;
 public int   ImageWidth;
 public int   ImageLength;
 public short  SamplesPerPixel;
 [MarshalAs( UnmanagedType.ByValArray, SizeConst=8)]
  public short[]  BitsPerSample;
 public short  BitsPerPixel;
 public short  Planar;
 public short  PixelType;
 public short  Compression;
 }

 [StructLayout(LayoutKind.Sequential, Pack=2)]
internal class TwPendingXfers
 {         // TW_PENDINGXFERS
 public short  Count;
 public int   EOJ;
 }

 [StructLayout(LayoutKind.Sequential, Pack=2)]
internal struct TwFix32
 {            // TW_FIX32
 public short  Whole;
 public ushort  Frac;
 
 public float ToFloat()
  {
  return (float) Whole + ( (float)Frac /65536.0f );
  }
 public void FromFloat( float f )
  {
  int i = (int)((f * 65536.0f) + 0.5f);
  Whole = (short) (i >> 16);
  Frac = (ushort) (i & 0x0000ffff);
  }
 }

 [StructLayout(LayoutKind.Sequential, Pack=2)]
internal class TwCapability
 {         // TW_CAPABILITY
 public TwCapability( TwCap cap )
  {
  Cap = (short) cap;
  ConType = -1;
  }
 public TwCapability( TwCap cap, short sval )
  {
  Cap = (short) cap;
  ConType = (short) TwOn.One;
  Handle = Twain.GlobalAlloc( 0x42, 6 );
  IntPtr pv = Twain.GlobalLock( Handle );
  Marshal.WriteInt16( pv, 0, (short) TwType.Int16 );
  Marshal.WriteInt32( pv, 2, (int) sval );
  Twain.GlobalUnlock( Handle );
  }
 ~TwCapability()
  {
  if( Handle != IntPtr.Zero )
   Twain.GlobalFree( Handle );
  }
 public short  Cap;
 public short  ConType;
 public IntPtr  Handle;
 }

} // namespace TwainLib

TwainLib.cs

using System;
using System.Collections;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace TwainLib
{
public enum TwainCommand
 {
 Not    = -1,
 Null   = 0,
 TransferReady = 1,
 CloseRequest = 2,
 CloseOk   = 3,
 DeviceEvent  = 4
 }

public class Twain
 {
 private const short CountryUSA  = 1;
 private const short LanguageUSA  = 13;

 public Twain()
  {
  appid = new TwIdentity();
  appid.Id    = IntPtr.Zero;
  appid.Version.MajorNum = 1;
  appid.Version.MinorNum = 1;
  appid.Version.Language = LanguageUSA;
  appid.Version.Country = CountryUSA;
  appid.Version.Info  = "Hack 1";
  appid.ProtocolMajor  = TwProtocol.Major;
  appid.ProtocolMinor  = TwProtocol.Minor;
  appid.SupportedGroups = (int)(TwDG.Image | TwDG.Control);
  appid.Manufacturer  = "NETMaster";
  appid.ProductFamily  = "Freeware";
  appid.ProductName  = "Hack";

  srcds = new TwIdentity();
  srcds.Id = IntPtr.Zero;

  evtmsg.EventPtr = Marshal.AllocHGlobal( Marshal.SizeOf( winmsg ) );
  }

 ~Twain()
  {
  Marshal.FreeHGlobal( evtmsg.EventPtr );
  }

 public void Init( IntPtr hwndp )
  {
  Finish();
  TwRC rc = DSMparent( appid, IntPtr.Zero, TwDG.Control, TwDAT.Parent, TwMSG.OpenDSM, ref hwndp );
  if( rc == TwRC.Success )
   {
   rc = DSMident( appid, IntPtr.Zero, TwDG.Control, TwDAT.Identity, TwMSG.GetDefault, srcds );
   if( rc == TwRC.Success )
    hwnd = hwndp;
   else
    rc = DSMparent( appid, IntPtr.Zero, TwDG.Control, TwDAT.Parent, TwMSG.CloseDSM, ref hwndp );
   }
  }

 public void Select()
  {
  TwRC rc;
  CloseSrc();
  if( appid.Id == IntPtr.Zero )
   {
   Init( hwnd );
   if( appid.Id == IntPtr.Zero )
    return;
   }
  rc = DSMident( appid, IntPtr.Zero, TwDG.Control, TwDAT.Identity, TwMSG.UserSelect, srcds );
  }

 public void Acquire()
  {
  TwRC rc;
  CloseSrc();
  if( appid.Id == IntPtr.Zero )
   {
   Init( hwnd );
   if( appid.Id == IntPtr.Zero )
    return;
   }
  rc = DSMident( appid, IntPtr.Zero, TwDG.Control, TwDAT.Identity, TwMSG.OpenDS, srcds );
  if( rc != TwRC.Success )
   return;

  TwCapability cap = new TwCapability( TwCap.XferCount, 1 );
  rc = DScap( appid, srcds, TwDG.Control, TwDAT.Capability, TwMSG.Set, cap );
  if( rc != TwRC.Success )
   {
   CloseSrc();
   return;
   }

  TwUserInterface guif = new TwUserInterface();
  guif.ShowUI = 1;
  guif.ModalUI = 1;
  guif.ParentHand = hwnd;
  rc = DSuserif( appid, srcds, TwDG.Control, TwDAT.UserInterface, TwMSG.EnableDS, guif );
  if( rc != TwRC.Success )
   {
   CloseSrc();
   return;
   }
  }

 public ArrayList TransferPictures()
  {
  ArrayList pics = new ArrayList();
  if( srcds.Id == IntPtr.Zero )
   return pics;

  TwRC rc;
  IntPtr hbitmap = IntPtr.Zero;
  TwPendingXfers pxfr = new TwPendingXfers();
  
  do
   {
   pxfr.Count = 0;
   hbitmap = IntPtr.Zero;

   TwImageInfo iinf = new TwImageInfo();
   rc = DSiinf( appid, srcds, TwDG.Image, TwDAT.ImageInfo, TwMSG.Get, iinf );
   if( rc != TwRC.Success )
    {
    CloseSrc();
    return pics;
    }

   rc = DSixfer( appid, srcds, TwDG.Image, TwDAT.ImageNativeXfer, TwMSG.Get, ref hbitmap );
   if( rc != TwRC.XferDone )
    {
    CloseSrc();
    return pics;
    }

   rc = DSpxfer( appid, srcds, TwDG.Control, TwDAT.PendingXfers, TwMSG.EndXfer, pxfr );
   if( rc != TwRC.Success )
    {
    CloseSrc();
    return pics;
    }

   pics.Add( hbitmap );
   }
  while( pxfr.Count != 0 );

  rc = DSpxfer( appid, srcds, TwDG.Control, TwDAT.PendingXfers, TwMSG.Reset, pxfr );
  return pics;
  }

 public TwainCommand PassMessage( ref Message m )
  {
  if( srcds.Id == IntPtr.Zero )
   return TwainCommand.Not;

  int pos = GetMessagePos();

  winmsg.hwnd  = m.HWnd;
  winmsg.message = m.Msg;
  winmsg.wParam = m.WParam;
  winmsg.lParam = m.LParam;
  winmsg.time  = GetMessageTime();
  winmsg.x  = (short) pos;
  winmsg.y  = (short) (pos >> 16);
  
  Marshal.StructureToPtr( winmsg, evtmsg.EventPtr, false );
  evtmsg.Message = 0;
  TwRC rc = DSevent( appid, srcds, TwDG.Control, TwDAT.Event, TwMSG.ProcessEvent, ref evtmsg );
  if( rc == TwRC.NotDSEvent )
   return TwainCommand.Not;
  if( evtmsg.Message == (short) TwMSG.XFerReady )
   return TwainCommand.TransferReady;
  if( evtmsg.Message == (short) TwMSG.CloseDSReq )
   return TwainCommand.CloseRequest;
  if( evtmsg.Message == (short) TwMSG.CloseDSOK )
   return TwainCommand.CloseOk;
  if( evtmsg.Message == (short) TwMSG.DeviceEvent )
   return TwainCommand.DeviceEvent;

  return TwainCommand.Null;
  }

 public void CloseSrc()
  {
  TwRC rc;
  if( srcds.Id != IntPtr.Zero )
   {
   TwUserInterface guif = new TwUserInterface();
   rc = DSuserif( appid, srcds, TwDG.Control, TwDAT.UserInterface, TwMSG.DisableDS, guif );
   rc = DSMident( appid, IntPtr.Zero, TwDG.Control, TwDAT.Identity, TwMSG.CloseDS, srcds );
   }
  }

 public void Finish()
  {
  TwRC rc;
  CloseSrc();
  if( appid.Id != IntPtr.Zero )
   rc = DSMparent( appid, IntPtr.Zero, TwDG.Control, TwDAT.Parent, TwMSG.CloseDSM, ref hwnd );
  appid.Id = IntPtr.Zero;
  }

 private IntPtr  hwnd;
 private TwIdentity appid;
 private TwIdentity srcds;
 private TwEvent  evtmsg;
 private WINMSG  winmsg;
 

 // ------ DSM entry point DAT_ variants:
  [DllImport("twain_32.dll", EntryPoint="#1")]
 private static extern TwRC DSMparent( [In, Out] TwIdentity origin, IntPtr zeroptr, TwDG dg, TwDAT dat, TwMSG msg, ref IntPtr refptr );

  [DllImport("twain_32.dll", EntryPoint="#1")]
 private static extern TwRC DSMident( [In, Out] TwIdentity origin, IntPtr zeroptr, TwDG dg, TwDAT dat, TwMSG msg, [In, Out] TwIdentity idds );

  [DllImport("twain_32.dll", EntryPoint="#1")]
 private static extern TwRC DSMstatus( [In, Out] TwIdentity origin, IntPtr zeroptr, TwDG dg, TwDAT dat, TwMSG msg, [In, Out] TwStatus dsmstat );

 // ------ DSM entry point DAT_ variants to DS:
  [DllImport("twain_32.dll", EntryPoint="#1")]
 private static extern TwRC DSuserif( [In, Out] TwIdentity origin, [In, Out] TwIdentity dest, TwDG dg, TwDAT dat, TwMSG msg, TwUserInterface guif );

  [DllImport("twain_32.dll", EntryPoint="#1")]
 private static extern TwRC DSevent( [In, Out] TwIdentity origin, [In, Out] TwIdentity dest, TwDG dg, TwDAT dat, TwMSG msg, ref TwEvent evt );

  [DllImport("twain_32.dll", EntryPoint="#1")]
 private static extern TwRC DSstatus( [In, Out] TwIdentity origin, [In] TwIdentity dest, TwDG dg, TwDAT dat, TwMSG msg, [In, Out] TwStatus dsmstat );

  [DllImport("twain_32.dll", EntryPoint="#1")]
 private static extern TwRC DScap( [In, Out] TwIdentity origin, [In] TwIdentity dest, TwDG dg, TwDAT dat, TwMSG msg, [In, Out] TwCapability capa );

  [DllImport("twain_32.dll", EntryPoint="#1")]
 private static extern TwRC DSiinf( [In, Out] TwIdentity origin, [In] TwIdentity dest, TwDG dg, TwDAT dat, TwMSG msg, [In, Out] TwImageInfo imginf );

  [DllImport("twain_32.dll", EntryPoint="#1")]
 private static extern TwRC DSixfer( [In, Out] TwIdentity origin, [In] TwIdentity dest, TwDG dg, TwDAT dat, TwMSG msg, ref IntPtr hbitmap );

  [DllImport("twain_32.dll", EntryPoint="#1")]
 private static extern TwRC DSpxfer( [In, Out] TwIdentity origin, [In] TwIdentity dest, TwDG dg, TwDAT dat, TwMSG msg, [In, Out] TwPendingXfers pxfr

);

  [DllImport("kernel32.dll", ExactSpelling=true)]
 internal static extern IntPtr GlobalAlloc( int flags, int size );
  [DllImport("kernel32.dll", ExactSpelling=true)]
 internal static extern IntPtr GlobalLock( IntPtr handle );
  [DllImport("kernel32.dll", ExactSpelling=true)]
 internal static extern bool GlobalUnlock( IntPtr handle );
  [DllImport("kernel32.dll", ExactSpelling=true)]
 internal static extern IntPtr GlobalFree( IntPtr handle );

  [DllImport("user32.dll", ExactSpelling=true)]
 private static extern int GetMessagePos();
  [DllImport("user32.dll", ExactSpelling=true)]
 private static extern int GetMessageTime();

  [DllImport("gdi32.dll", ExactSpelling=true)]
 private static extern int GetDeviceCaps( IntPtr hDC, int nIndex );

  [DllImport("gdi32.dll", CharSet=CharSet.Auto)]
 private static extern IntPtr CreateDC( string szdriver, string szdevice, string szoutput, IntPtr devmode );

  [DllImport("gdi32.dll", ExactSpelling=true)]
 private static extern bool DeleteDC( IntPtr hdc );

 public static int ScreenBitDepth {
  get {
   IntPtr screenDC = CreateDC( "DISPLAY", null, null, IntPtr.Zero );
   int bitDepth = GetDeviceCaps( screenDC, 12 );
   bitDepth *= GetDeviceCaps( screenDC, 14 );
   DeleteDC( screenDC );
   return bitDepth;
   }
  }

  [StructLayout(LayoutKind.Sequential, Pack=4)]
 internal struct WINMSG
  {
  public IntPtr  hwnd;
  public int   message;
  public IntPtr  wParam;
  public IntPtr  lParam;
  public int   time;
  public int   x;
  public int   y;
  }

 } // class Twain
}