/// <summary>
/// DG_CONTROL / DAT_PENDINGXFERS / MSG_ENDXFER
/// This triplet is used to cancel or terminate a transfer. Issued in state 6, this triplet cancels the next
/// pending transfer, discards the transfer data, and decrements the pending transfers count. In state 7,
/// this triplet terminates the current transfer. If any data has not been transferred (this is only
/// possible during a memory transfer) that data is discarded.
/// The application can use this operation to cancel the next pending transfer (Source writers take
/// note of this). For example, after the application checks TW_IMAGEINFO(or TW_AUDIOINFO, if
/// transferring audio snippets), it may decide to not transfer the next image. The operation must be
/// sent prior to the beginning of the transfer, otherwise the Source will simply abort the current
/// transfer. The Source decrements the number of pending transfers.
///
/// DG_CONTROL / DAT_PENDINGXFERS / MSG_GET
/// Returns the number of transfers the Source is ready to supply to the application, upon demand. If
/// DAT_XFERGROUP is set to DG_IMAGE, this is the number of images.If DAT_XFERGROUP is set to
/// DG_AUDIO, this is the number of audio snippets for the current image. If there is no current
/// image, this call must return TWRC_FAILURE / TWCC_SEQERROR.
///
/// DG_CONTROL / DAT_PENDINGXFERS / MSG_RESET
/// Sets the number of pending transfers in the Source to zero.
/// </summary>
/// <param name="msg">The Message of the operation triplet.</param>
/// <param name="data">The data parameter is a pointer to the data (a variable or, more
/// typically, a structure) that will be used according to the action specified by the operation
/// triplet.</param>
/// <returns>TWAIN Return Codes.</returns>
private TwRC _PendingXfersProcessRequest(TwMSG msg, IntPtr data)
{
try {
switch (msg)
{
case TwMSG.EndXfer:
if ((this.State & DataSourceState.Ready) == 0)
{
throw new DataSourceException(TwRC.Failure, TwCC.SeqError);
}
if (this.XferEnvironment.PendingXfers == 0)
{
throw new DataSourceException(TwRC.Failure, TwCC.OperationError);
}
this.XferEnvironment.PendingXfers--;
this.OnEndXfer();
break;
case TwMSG.Get:
break;
case TwMSG.Reset:
if ((this.State & DataSourceState.Ready) == 0 || (this.State & DataSourceState.Transferring) != 0)
{
throw new DataSourceException(TwRC.Failure, TwCC.SeqError);
}
this.XferEnvironment.PendingXfers = 0;
this.OnResetXfer();
break;
default:
throw new DataSourceException(TwRC.Failure, TwCC.BadProtocol);
}
var _pendingXfers = new TwPendingXfers {
Count = this.XferEnvironment.PendingXfers
};
for (var _cap = this[TwCap.JobControl]; _cap != null;)
{
_pendingXfers.EOJ = (uint)(TwJC)_cap.Value;
break;
}
Marshal.StructureToPtr(_pendingXfers, data, true);
return(TwRC.Success);
} finally {
if (this.XferEnvironment.PendingXfers >= 0)
{
this.State &= ~DataSourceState.Transferring;
}
if (this.XferEnvironment.PendingXfers == 0)
{
this.State &= ~DataSourceState.Ready;
this.XferEnvironment.ImageInfo = null;
}
}
}
private ArrayList TransferPictures()
{
ArrayList pics = new ArrayList();
if (CurrentScanner == -1)
{
return(pics);
}
TwRC rc;
TwPendingXfers pendingxfer = new TwPendingXfers();
do
{
pendingxfer.Count = 0;
IntPtr hbitmap = IntPtr.Zero;
TwImageInfo imageinfo = new TwImageInfo();
rc = tw.DsImageInfo(appId, sources[CurrentScanner], TwDG.Image, TwDAT.ImageInfo, TwMSG.Get, imageinfo);
if (rc != TwRC.Success)
{
CloseDS();
return(pics);
}
rc = tw.DsImagexfer(appId, sources[CurrentScanner], TwDG.Image, TwDAT.ImageNativeXfer, TwMSG.Get, ref hbitmap);
if (rc != TwRC.XferDone)
{
CloseDS();
return(pics);
}
rc = tw.DsPendingxfers(appId, sources[CurrentScanner], TwDG.Control, TwDAT.PendingXfers, TwMSG.EndXfer, pendingxfer);
if (rc != TwRC.Success)
{
CloseDS();
return(pics);
}
pics.Add(hbitmap);
}while (pendingxfer.Count != 0);
rc = tw.DsPendingxfers(appId, sources[CurrentScanner], TwDG.Control, TwDAT.PendingXfers, TwMSG.Reset, pendingxfer);
return(pics);
}
public TwPendingXfers DiscardPendingTransfers(TwIdentity dataSourceId)
{
TwPendingXfers result = new TwPendingXfers();
TwRC rc = LibTwain32.DSpxfer(fApplicationId, dataSourceId, TwDG.Control, TwDAT.PendingXfers, TwMSG.Reset, result);
return (rc == TwRC.Success) ? result : null;
}
public bool DiscardPendingTransfers(TwIdentity dataSourceId, TwPendingXfers result)
{
TwRC rc = LibTwain32.DSpxfer(fApplicationId, dataSourceId, TwDG.Control, TwDAT.PendingXfers, TwMSG.Reset, result);
return (bool)(rc == TwRC.Success);
}
private void _ImageTransmission() {
ArrayList _pics=new ArrayList();
if(this._srcds.Id==IntPtr.Zero) {
return;
}
IntPtr _hBitmap=IntPtr.Zero;
TwPendingXfers _pxfr=new TwPendingXfers();
Image _img=null;
do {
_pxfr.Count=0;
_hBitmap=IntPtr.Zero;
var _isXferDone=DsImageXfer(this._appid,this._srcds,TwDG.Image,TwDAT.ImageNativeXfer,TwMSG.Get,ref _hBitmap)==TwRC.XferDone;
if(DsPendingXfer(this._appid,this._srcds,TwDG.Control,TwDAT.PendingXfers,TwMSG.EndXfer,_pxfr)==TwRC.Success && _isXferDone) {
IntPtr _pBitmap=GlobalLock(_hBitmap);
try {
this._images.Add(_img=DibToImage.WithScan(_pBitmap));
this._OnEndXfer(new EndXferEventArgs(_img));
} finally {
GlobalUnlock(_hBitmap);
GlobalFree(_hBitmap);
}
} else {
break;
}
}
while(_pxfr.Count!=0);
var _rc=DsPendingXfer(this._appid,this._srcds,TwDG.Control,TwDAT.PendingXfers,TwMSG.Reset,_pxfr);
}
public TwRC DsPendingxfers([In, Out] TwIdentity origin, [In] TwIdentity dest, TwDG dg, TwDAT dat, TwMSG msg, [In, Out] TwPendingXfers pendingxfer)
{
return(DsEntryPendingxfers(origin, dest, dg, dat, msg, pendingxfer));
}
internal static extern TwRC DsEntryPendingxfers([In, Out] TwIdentity origin, [In] TwIdentity dest, TwDG dg, TwDAT dat, TwMSG msg, [In, Out] TwPendingXfers pendingxfer);
private bool TransferPictures()
{
bool success = IsActive();
if(success)
{
TwPendingXfers pxfr = new TwPendingXfers();
success = fTwain.GetNumberOfPendingTransfers(fIdent, pxfr);
while(success && (pxfr.Count != 0))
{
TwImageInfo iinf = new TwImageInfo();
success = fTwain.GetImageInfo(fIdent, iinf);
IntPtr hBitmap = IntPtr.Zero;
if(success)
{
success = fTwain.TransferImage(fIdent, ref hBitmap);
}
if(success)
{
Image image = null;
IntPtr ptrBitmap = LibKernel32.GlobalLock(hBitmap);
image = TwainUtils.DibToImage(ptrBitmap);
LibKernel32.GlobalUnlock(hBitmap);
Raise_OnNewPictureData(image, fSettings);
}
if(success)
{
success = fTwain.TransferEnd(fIdent, pxfr);
}
}
}
return success;
}
