TwainDefs.cs

/* Этот файл является частью библиотеки Saraff.Twain.DS
 * © SARAFF SOFTWARE (Кирножицкий Андрей), 2015.
 * Saraff.Twain.DS - свободная программа: вы можете перераспространять ее и/или
 * изменять ее на условиях Меньшей Стандартной общественной лицензии GNU в том виде,
 * в каком она была опубликована Фондом свободного программного обеспечения;
 * либо версии 3 лицензии, либо (по вашему выбору) любой более поздней
 * версии.
 * Saraff.Twain.DS распространяется в надежде, что она будет полезной,
 * но БЕЗО ВСЯКИХ ГАРАНТИЙ; даже без неявной гарантии ТОВАРНОГО ВИДА
 * или ПРИГОДНОСТИ ДЛЯ ОПРЕДЕЛЕННЫХ ЦЕЛЕЙ. Подробнее см. в Меньшей Стандартной
 * общественной лицензии GNU.
 * Вы должны были получить копию Меньшей Стандартной общественной лицензии GNU
 * вместе с этой программой. Если это не так, см.
 * <http://www.gnu.org/licenses/>.)
 * 
 * This file is part of Saraff.Twain.DS.
 * © SARAFF SOFTWARE (Kirnazhytski Andrei), 2015.
 * Saraff.Twain.DS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * Saraff.Twain.DS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public License
 * along with Saraff.Twain.DS. If not, see <http://www.gnu.org/licenses/>.
 * 
 * PLEASE SEND EMAIL TO:  twain@saraff.ru.
 */
/* Этот файл является частью библиотеки Saraff.Twain.NET
 * © SARAFF SOFTWARE (Кирножицкий Андрей), 2011.
 * Saraff.Twain.NET - свободная программа: вы можете перераспространять ее и/или
 * изменять ее на условиях Меньшей Стандартной общественной лицензии GNU в том виде,
 * в каком она была опубликована Фондом свободного программного обеспечения;
 * либо версии 3 лицензии, либо (по вашему выбору) любой более поздней
 * версии.
 * Saraff.Twain.NET распространяется в надежде, что она будет полезной,
 * но БЕЗО ВСЯКИХ ГАРАНТИЙ; даже без неявной гарантии ТОВАРНОГО ВИДА
 * или ПРИГОДНОСТИ ДЛЯ ОПРЕДЕЛЕННЫХ ЦЕЛЕЙ. Подробнее см. в Меньшей Стандартной
 * общественной лицензии GNU.
 * Вы должны были получить копию Меньшей Стандартной общественной лицензии GNU
 * вместе с этой программой. Если это не так, см.
 * <http://www.gnu.org/licenses/>.)
 * 
 * This file is part of Saraff.Twain.NET.
 * © SARAFF SOFTWARE (Kirnazhytski Andrei), 2011.
 * Saraff.Twain.NET is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * Saraff.Twain.NET is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public License
 * along with Saraff.Twain.NET. If not, see <http://www.gnu.org/licenses/>.
 * 
 * PLEASE SEND EMAIL TO:  twain@saraff.ru.
 */
using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Diagnostics;
using System.Drawing;

namespace Saraff.Twain.DS {

    #region Generic Constants

    /// <summary>
    /// Data Groups.
    /// </summary>
    [Flags]
    public enum TwDG:uint {									// DG_.....

        /// <summary>
        /// Data pertaining to control.
        /// </summary>
        Control=0x0001,

        /// <summary>
        /// Data pertaining to raster images.
        /// </summary>
        Image=0x0002,

        /// <summary>
        /// Data pertaining to audio.
        /// </summary>
        Audio=0x0004,

        /// <summary>
        /// added to the identity by the DSM.
        /// </summary>
        DSM2=0x10000000,

        /// <summary>
        /// Set by the App to indicate it would prefer to use DSM2.
        /// </summary>
        APP2=0x20000000,

        /// <summary>
        /// Set by the DS to indicate it would prefer to use DSM2.
        /// </summary>
        DS2=0x40000000
    }

    /// <summary>
    /// Data codes.
    /// </summary>
    public enum TwDAT:ushort {									// DAT_....

        #region Data Argument Types for the DG_CONTROL Data Group.

        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,
        Callback=0x0010,   /* TW_CALLBACK        Added 2.0         */
        StatusUtf8=0x0011, /* TW_STATUSUTF8      Added 2.1         */
        Callback2=0x0012,

        #endregion

        #region Data Argument Types for the DG_IMAGE Data Group.

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

        #endregion

        #region misplaced

        IccProfile=0x0401,       /* TW_MEMORY        Added 1.91  This Data Argument is misplaced but belongs to the DG_IMAGE Data Group */
        ImageMemFileXfer=0x0402, /* TW_IMAGEMEMXFER  Added 1.91  This Data Argument is misplaced but belongs to the DG_IMAGE Data Group */
        EntryPoint=0x0403,       /* TW_ENTRYPOINT    Added 2.0   This Data Argument is misplaced but belongs to the DG_CONTROL Data Group */

        #endregion
    }

    /// <summary>
    /// Messages.
    /// </summary>
    public enum TwMSG:ushort {									// MSG_.....

        #region Generic messages may be used with any of several DATs.

        /// <summary>
        /// Used in TW_EVENT structure.
        /// </summary>
        Null=0x0000,

        /// <summary>
        /// Get one or more values.
        /// </summary>
        Get=0x0001,

        /// <summary>
        /// Get current value.
        /// </summary>
        GetCurrent=0x0002,

        /// <summary>
        /// Get default (e.g. power up) value.
        /// </summary>
        GetDefault=0x0003,

        /// <summary>
        /// Get first of a series of items, e.g. DSs.
        /// </summary>
        GetFirst=0x0004,

        /// <summary>
        /// Iterate through a series of items.
        /// </summary>
        GetNext=0x0005,

        /// <summary>
        /// Set one or more values.
        /// </summary>
        Set=0x0006,

        /// <summary>
        /// Set current value to default value.
        /// </summary>
        Reset=0x0007,

        /// <summary>
        /// Get supported operations on the cap.
        /// </summary>
        QuerySupport=0x0008,

        #endregion

        #region Messages used with DAT_NULL

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

        #endregion

        #region Messages used with a pointer to a DAT_STATUS structure

        /// <summary>
        /// Get status information
        /// </summary>
        CheckStatus=0x0201,

        #endregion

        #region Messages used with a pointer to DAT_PARENT entry

        /// <summary>
        /// Open the DSM
        /// </summary>
        OpenDSM=0x0301,

        /// <summary>
        /// Close the DSM
        /// </summary>
        CloseDSM=0x0302,

        #endregion

        #region Messages used with a pointer to a DAT_IDENTITY structure

        /// <summary>
        /// Open a entry source
        /// </summary>
        OpenDS=0x0401,

        /// <summary>
        /// Close a entry source
        /// </summary>
        CloseDS=0x0402,

        /// <summary>
        /// Put up a dialog of all DS
        /// </summary>
        UserSelect=0x0403,

        #endregion

        #region Messages used with a pointer to a DAT_USERINTERFACE structure

        /// <summary>
        /// Disable entry transfer in the DS
        /// </summary>
        DisableDS=0x0501,

        /// <summary>
        /// Enabled entry transfer in the DS
        /// </summary>
        EnableDS=0x0502,

        /// <summary>
        /// Enabled for saving DS state only.
        /// </summary>
        EnableDSUIOnly=0x0503,

        #endregion

        #region Messages used with a pointer to a DAT_EVENT structure

        ProcessEvent=0x0601,

        #endregion

        #region Messages used with a pointer to a DAT_PENDINGXFERS structure

        EndXfer=0x0701,
        StopFeeder=0x0702,

        #endregion

        #region Messages used with a pointer to a DAT_FILESYSTEM structure

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

        #endregion

        #region Messages used with a pointer to a DAT_PASSTHRU structure

        PassThru=0x0901,

        #endregion

        #region used with DAT_CALLBACK

        RegisterCallback=0x0902,

        #endregion

        #region used with DAT_CAPABILITY

        ResetAll=0x0A01

        #endregion
    }

    /// <summary>
    /// Return Codes
    /// </summary>
    public enum TwRC:ushort {									// TWRC_....
        Success=0x0000,
        Failure=0x0001,
        CheckStatus=0x0002,
        Cancel=0x0003,
        DSEvent=0x0004,
        NotDSEvent=0x0005,
        XferDone=0x0006,
        EndOfList=0x0007,
        InfoNotSupported=0x0008,
        DataNotAvailable=0x0009,
        Busy=10,
        ScannerLocked=11
    }

    /// <summary>
    /// Condition Codes
    /// </summary>
    public enum TwCC:ushort {									// 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,
        InterLock=24,
        DamagedCorner=25,
        FocusError=26,
        DocTooLight=27,
        DocTooDark=28,
        NoMedia=29,
    }

    /// <summary>
    /// Generic Constants
    /// </summary>
    public enum TwOn:ushort {									// TWON_....

        /// <summary>
        /// Indicates TW_ARRAY container
        /// </summary>
        Array=0x0003,

        /// <summary>
        /// Indicates TW_ENUMERATION container
        /// </summary>
        Enum=0x0004,

        /// <summary>
        /// Indicates TW_ONEVALUE container
        /// </summary>
        One=0x0005,

        /// <summary>
        /// Indicates TW_RANGE container
        /// </summary>
        Range=0x0006,
        DontCare=0xffff
    }

    /// <summary>
    /// Data Types
    /// </summary>
    public enum TwType:ushort {									// 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,
        Uni512=0x000e,
        Handle=0x000f
    }

    /// <summary>
    /// Вспомогательный класс для типов twain.
    /// </summary>
    internal sealed class TwTypeHelper {
        private static Dictionary<TwType, Type> _typeof=new Dictionary<TwType, Type> {
            {TwType.Int8,typeof(sbyte)},
            {TwType.Int16,typeof(short)},
            {TwType.Int32,typeof(int)},
            {TwType.UInt8,typeof(byte)},
            {TwType.UInt16,typeof(ushort)},
            {TwType.UInt32,typeof(uint)},
            {TwType.Bool,typeof(TwBool)},
            {TwType.Fix32,typeof(TwFix32)},
            {TwType.Frame,typeof(TwFrame)},
            {TwType.Str32,typeof(TwStr32)},
            {TwType.Str64,typeof(TwStr64)},
            {TwType.Str128,typeof(TwStr128)},
            {TwType.Str255,typeof(TwStr255)},
            {TwType.Str1024,typeof(TwStr1024)},
            {TwType.Uni512,typeof(TwUni512)},
            {TwType.Handle,typeof(IntPtr)}
        };
        private static Dictionary<int, TwType> _typeofAux=new Dictionary<int, TwType> { 
            {32,TwType.Str32},
            {64,TwType.Str64},
            {128,TwType.Str128},
            {255,TwType.Str255},
            {1024,TwType.Str1024},
            {512,TwType.Uni512}
        };

        /// <summary>
        /// Возвращает соответствующий twain-типу управляемый тип.
        /// </summary>
        /// <param name="type">Код типа данный twain.</param>
        /// <returns>Управляемый тип.</returns>
        internal static Type TypeOf(TwType type) {
            return TwTypeHelper._typeof[type];
        }

        /// <summary>
        /// Возвращает соответствующий управляемому типу twain-тип.
        /// </summary>
        /// <param name="type">Управляемый тип.</param>
        /// <returns>Код типа данный twain.</returns>
        internal static TwType TypeOf(Type type) {
            Type _type=type.IsEnum?Enum.GetUnderlyingType(type):type;
            foreach(var _item in TwTypeHelper._typeof) {
                if(_item.Value==_type) {
                    return _item.Key;
                }
            }
            if(type==typeof(bool)) {
                return TwType.Bool;
            }
            if(type==typeof(float)) {
                return TwType.Fix32;
            }
            if(type==typeof(RectangleF)) {
                return TwType.Frame;
            }
            throw new KeyNotFoundException();
        }

        /// <summary>
        /// Возвращает соответствующий объекту twain-тип.
        /// </summary>
        /// <param name="obj">Объект.</param>
        /// <returns>Код типа данный twain.</returns>
        internal static TwType TypeOf(object obj) {
            if(obj is string) {
                return TwTypeHelper._typeofAux[((string)obj).Length];
            }
            return TwTypeHelper.TypeOf(obj.GetType());
        }

        /// <summary>
        /// Возвращает размер twain-типа в неуправляемом блоке памяти.
        /// </summary>
        /// <param name="type">Код типа данный twain.</param>
        /// <returns>Размер в байтах.</returns>
        internal static int SizeOf(TwType type) {
            return Marshal.SizeOf(TwTypeHelper._typeof[type]);
        }

        /// <summary>
        /// Приводит внутренние типы компонента к общим типам среды.
        /// </summary>
        /// <param name="type">Код twain-типа.</param>
        /// <param name="value">Экземпляр объекта.</param>
        /// <returns>Экземпляр объекта.</returns>
        internal static object CastToCommon(TwType type, object value) {
            switch(type) {
                case TwType.Bool:
                    return (bool)(TwBool)value;
                case TwType.Fix32:
                    return (float)(TwFix32)value;
                case TwType.Frame:
                    return (RectangleF)(TwFrame)value;
                case TwType.Str128:
                case TwType.Str255:
                case TwType.Str32:
                case TwType.Str64:
                case TwType.Uni512:
                case TwType.Str1024:
                    return value.ToString();
            }
            return value;
        }

        /// <summary>
        /// Приводит общие типы среды к внутренним типам компонента.
        /// </summary>
        /// <param name="type">Код twain-типа.</param>
        /// <param name="value">Экземпляр объекта.</param>
        /// <returns>Экземпляр объекта.</returns>
        internal static object CastToTw(TwType type, object value) {
            switch(type) {
                case TwType.Bool:
                    return (TwBool)(bool)value;
                case TwType.Fix32:
                    return (TwFix32)(float)value;
                case TwType.Frame:
                    return (TwFrame)(RectangleF)value;
                case TwType.Str32:
                    return (TwStr32)value.ToString();
                case TwType.Str64:
                    return (TwStr64)value.ToString();
                case TwType.Str128:
                    return (TwStr128)value.ToString();
                case TwType.Str255:
                    return (TwStr255)value.ToString();
                case TwType.Uni512:
                    return (TwUni512)value.ToString();
                case TwType.Str1024:
                    return (TwStr1024)value.ToString();
            }

            Type _type=value.GetType();
            if(_type.IsEnum&&Enum.GetUnderlyingType(_type)==TwTypeHelper.TypeOf(type)) {
                return Convert.ChangeType(value, Enum.GetUnderlyingType(_type));
            }

            return value;
        }

        /// <summary>
        /// Выполняет преобразование значения в экземпляр внутреннего типа компонента.
        /// </summary>
        /// <typeparam name="T">Тип значения.</typeparam>
        /// <param name="type">Код twain-типа.</param>
        /// <param name="value">Значение.</param>
        /// <returns>Экземпляр объекта.</returns>
        internal static object ValueToTw<T>(TwType type, T value) {
            int _size=Marshal.SizeOf(typeof(T));
            IntPtr _mem=Marshal.AllocHGlobal(_size);
            DataSourceServices.Memory.ZeroMemory(_mem, (IntPtr)_size);
            try {
                Marshal.StructureToPtr(value, _mem, true);
                return Marshal.PtrToStructure(_mem, TwTypeHelper.TypeOf(type));
            } finally {
                Marshal.FreeHGlobal(_mem);
            }
        }

        /// <summary>
        /// Выполняет преобразование экземпляра внутреннего типа компонента в значение.
        /// </summary>
        /// <typeparam name="T">Тип значения.</typeparam>
        /// <param name="value">Экземпляр объекта.</param>
        /// <returns>Значение.</returns>
        internal static T ValueFromTw<T>(object value) {
            int _size=Math.Max(Marshal.SizeOf(typeof(T)), Marshal.SizeOf(value));
            IntPtr _mem=Marshal.AllocHGlobal(_size);
            DataSourceServices.Memory.ZeroMemory(_mem, (IntPtr)_size);
            try {
                Marshal.StructureToPtr(value, _mem, true);
                return (T)Marshal.PtrToStructure(_mem, typeof(T));
            } finally {
                Marshal.FreeHGlobal(_mem);
            }
        }
    }

    /// <summary>
    /// Capability Constants
    /// </summary>
    public enum TwCap:ushort {
        /* image entry sources MAY support these caps */
        XferCount=0x0001,			// all entry sources are REQUIRED to support these caps
        ICompression=0x0100,		// ICAP_...
        IPixelType=0x0101,
        IUnits=0x0102,              //default is TWUN_INCHES
        IXferMech=0x0103,
        AutoBright=0x1100,
        Brightness=0x1101,
        Contrast=0x1103,
        CustHalfTone=0x1104,
        ExposureTime=0x1105,
        Filter=0x1106,
        Flashused=0x1107,
        Gamma=0x1108,
        HalfTones=0x1109,
        Highlight=0x110a,
        ImageFileFormat=0x110c,
        LampState=0x110d,
        LightSource=0x110e,
        Orientation=0x1110,
        PhysicalWidth=0x1111,
        PhysicalHeight=0x1112,
        Shadow=0x1113,
        Frames=0x1114,
        XNativeResolution=0x1116,
        YNativeResolution=0x1117,
        XResolution=0x1118,
        YResolution=0x1119,
        MaxFrames=0x111a,
        Tiles=0x111b,
        BitOrder=0x111c,
        CCITTKFactor=0x111d,
        LightPath=0x111e,
        PixelFlavor=0x111f,
        PlanarChunky=0x1120,
        Rotation=0x1121,
        SupportedSizes=0x1122,
        Threshold=0x1123,
        XScaling=0x1124,
        YScaling=0x1125,
        BitOrderCodes=0x1126,
        PixelFlavorCodes=0x1127,
        JpegPixelType=0x1128,
        TimeFill=0x112a,
        BitDepth=0x112b,
        BitDepthReduction=0x112c,  /* Added 1.5 */
        UndefinedImageSize=0x112d,  /* Added 1.6 */
        ImageDataSet=0x112e,  /* Added 1.7 */
        ExtImageInfo=0x112f,  /* Added 1.7 */
        MinimumHeight=0x1130,  /* Added 1.7 */
        MinimumWidth=0x1131,  /* Added 1.7 */
        AutoDiscardBlankPages=0x1134,  /* Added 2.0 */
        FlipRotation=0x1136,  /* Added 1.8 */
        BarCodeDetectionEnabled=0x1137,  /* Added 1.8 */
        SupportedBarCodeTypes=0x1138,  /* Added 1.8 */
        BarCodeMaxSearchPriorities=0x1139,  /* Added 1.8 */
        BarCodeSearchPriorities=0x113a,  /* Added 1.8 */
        BarCodeSearchMode=0x113b,  /* Added 1.8 */
        BarCodeMaxRetries=0x113c,  /* Added 1.8 */
        BarCodeTimeout=0x113d,  /* Added 1.8 */
        ZoomFactor=0x113e,  /* Added 1.8 */
        PatchCodeDetectionEnabled=0x113f,  /* Added 1.8 */
        SupportedPatchCodeTypes=0x1140,  /* Added 1.8 */
        PatchCodeMaxSearchPriorities=0x1141,  /* Added 1.8 */
        PatchCodeSearchPriorities=0x1142,  /* Added 1.8 */
        PatchCodeSearchMode=0x1143,  /* Added 1.8 */
        PatchCodeMaxRetries=0x1144,  /* Added 1.8 */
        PatchCodeTimeout=0x1145,  /* Added 1.8 */
        FlashUsed2=0x1146,  /* Added 1.8 */
        ImageFilter=0x1147,  /* Added 1.8 */
        NoiseFilter=0x1148,  /* Added 1.8 */
        OverScan=0x1149,  /* Added 1.8 */
        AutomaticBorderDetection=0x1150,  /* Added 1.8 */
        AutomaticDeskew=0x1151,  /* Added 1.8 */
        AutomaticRotate=0x1152,  /* Added 1.8 */
        JpegQuality=0x1153,  /* Added 1.9 */
        FeederType=0x1154,
        IccProfile=0x1155,
        AutoSize=0x1156,
        AutomaticCropUsesFrame=0x1157,
        AutomaticLengthDetection=0x1158,
        AutomaticColorEnabled=0x1159,
        AutomaticColorNonColorPixelType=0x115a,
        ColorManagementEnabled=0x115b,
        ImageMerge=0x115c,
        ImageMergeHeightThreshold=0x115d,
        SupportedExtimageInfo=0x115e,
        FilmType=0x115f,
        Mirror=0x1160,
        JpegSubSampling=0x1161,

        /* all entry sources MAY support these caps */
        Author=0x1000,
        Caption=0x1001,
        FeederEnabled=0x1002,
        FeederLoaded=0x1003,
        TimeDate=0x1004,
        SupportedCaps=0x1005,
        ExtendedCaps=0x1006,
        AutoFeed=0x1007,
        ClearPage=0x1008,
        FeedPage=0x1009,
        RewindPage=0x100a,
        Indicators=0x100b,   /* Added 1.1 */
        SupportedCapsExt=0x100c,   /* Added 1.6 */
        PaperDetectable=0x100d,   /* Added 1.6 */
        UIControllable=0x100e,   /* Added 1.6 */
        DeviceOnline=0x100f,   /* Added 1.6 */
        AutoScan=0x1010,   /* Added 1.6 */
        ThumbnailsEnabled=0x1011,   /* Added 1.7 */
        Duplex=0x1012,   /* Added 1.7 */
        DuplexEnabled=0x1013,   /* Added 1.7 */
        EnableDSUIOnly=0x1014,   /* Added 1.7 */
        CustomDSData=0x1015,   /* Added 1.7 */
        Endorser=0x1016,   /* Added 1.7 */
        JobControl=0x1017,   /* Added 1.7 */
        Alarms=0x1018,   /* Added 1.8 */
        AlarmVolume=0x1019,   /* Added 1.8 */
        AutomaticCapture=0x101a,   /* Added 1.8 */
        TimeBeforeFirstCapture=0x101b,   /* Added 1.8 */
        TimeBetweenCaptures=0x101c,   /* Added 1.8 */
        ClearBuffers=0x101d,   /* Added 1.8 */
        MaxBatchBuffers=0x101e,   /* Added 1.8 */
        DeviceTimeDate=0x101f,   /* Added 1.8 */
        PowerSupply=0x1020,   /* Added 1.8 */
        CameraPreviewUI=0x1021,   /* Added 1.8 */
        DeviceEvent=0x1022,   /* Added 1.8 */
        SerialNumber=0x1024,   /* Added 1.8 */
        Printer=0x1026,   /* Added 1.8 */
        PrinterEnabled=0x1027,   /* Added 1.8 */
        PrinterIndex=0x1028,   /* Added 1.8 */
        PrinterMode=0x1029,   /* Added 1.8 */
        PrinterString=0x102a,   /* Added 1.8 */
        PrinterSuffix=0x102b,   /* Added 1.8 */
        Language=0x102c,   /* Added 1.8 */
        FeederAlignment=0x102d,   /* Added 1.8 */
        FeederOrder=0x102e,   /* Added 1.8 */
        ReacquireAllowed=0x1030,   /* Added 1.8 */
        BatteryMinutes=0x1032,   /* Added 1.8 */
        BatteryPercentage=0x1033,   /* Added 1.8 */
        CameraSide=0x1034,
        Segmented=0x1035,
        CameraEnabled=0x1036,
        CameraOrder=0x1037,
        MicrEnabled=0x1038,
        FeederPrep=0x1039,
        FeederPocket=0x103a,
        AutomaticSenseMedium=0x103b,
        CustomInterfaceGuid=0x103c,
        SupportedCapsSegmentUnique=0x103d,
        SupportedDats=0x103e,
        DoubleFeedDetection=0x103f,
        DoubleFeedDetectionLength=0x1040,
        DoubleFeedDetectionSensitivity=0x1041,
        DoubleFeedDetectionResponse=0x1042,
        PaperHandling=0x1043,
        IndicatorsMode=0x1044,
        PrinterVerticalOffset=0x1045,
        PowerSaveTime=0x1046,
        PrinterCharRotation=0x1047,
        PrinterFontStyle=0x1048,
        PrinterIndexLeadChar=0x1049,
        PrinterIndexMaxValue=0x104A,
        PrinterIndexNumDigits=0x104B,
        PrinterIndexStep=0x104C,
        PrinterIndexTrigger=0x104D,
        PrinterStringPreview=0x104E
    }

    /// <summary>
    /// Bit patterns: for query the operation that are supported by the entry source on a capability
    /// </summary>
    [Flags]
    public enum TwQC:ushort { //TWQC_...
        Get=0x0001,
        Set=0x0002,
        GetDefault=0x0004,
        GetCurrent=0x0008,
        Reset=0x0010,
        SetConstraint=0x0020,
        ConstrainAble=0x0040,
        GetHelp=0x0100,
        GetLabel=0x0200,
        GetLabelEnum=0x0400
    }

    /// <summary>
    /// Language Constants
    /// </summary>
    public enum TwLanguage:ushort {
        DANISH=0,             /* Danish                 */
        DUTCH=1,              /* Dutch                  */
        ENGLISH=2,            /* International English  */
        FRENCH_CANADIAN=3,    /* French Canadian        */
        FINNISH=4,            /* Finnish                */
        FRENCH=5,             /* French                 */
        GERMAN=6,             /* German                 */
        ICELANDIC=7,          /* Icelandic              */
        ITALIAN=8,            /* Italian                */
        NORWEGIAN=9,          /* Norwegian              */
        PORTUGUESE=10,        /* Portuguese             */
        SPANISH=11,           /* Spanish                */
        SWEDISH=12,           /* Swedish                */
        ENGLISH_USA=13,       /* U.S. English           */
        AFRIKAANS=14,
        ALBANIA=15,
        ARABIC=16,
        ARABIC_ALGERIA=17,
        ARABIC_BAHRAIN=18,
        ARABIC_EGYPT=19,
        ARABIC_IRAQ=20,
        ARABIC_JORDAN=21,
        ARABIC_KUWAIT=22,
        ARABIC_LEBANON=23,
        ARABIC_LIBYA=24,
        ARABIC_MOROCCO=25,
        ARABIC_OMAN=26,
        ARABIC_QATAR=27,
        ARABIC_SAUDIARABIA=28,
        ARABIC_SYRIA=29,
        ARABIC_TUNISIA=30,
        ARABIC_UAE=31, /* United Arabic Emirates */
        ARABIC_YEMEN=32,
        BASQUE=33,
        BYELORUSSIAN=34,
        BULGARIAN=35,
        CATALAN=36,
        CHINESE=37,
        CHINESE_HONGKONG=38,
        CHINESE_PRC=39, /* People's Republic of China */
        CHINESE_SINGAPORE=40,
        CHINESE_SIMPLIFIED=41,
        CHINESE_TAIWAN=42,
        CHINESE_TRADITIONAL=43,
        CROATIA=44,
        CZECH=45,
        DUTCH_BELGIAN=46,
        ENGLISH_AUSTRALIAN=47,
        ENGLISH_CANADIAN=48,
        ENGLISH_IRELAND=49,
        ENGLISH_NEWZEALAND=50,
        ENGLISH_SOUTHAFRICA=51,
        ENGLISH_UK=52,
        ESTONIAN=53,
        FAEROESE=54,
        FARSI=55,
        FRENCH_BELGIAN=56,
        FRENCH_LUXEMBOURG=57,
        FRENCH_SWISS=58,
        GERMAN_AUSTRIAN=59,
        GERMAN_LUXEMBOURG=60,
        GERMAN_LIECHTENSTEIN=61,
        GERMAN_SWISS=62,
        GREEK=63,
        HEBREW=64,
        HUNGARIAN=65,
        INDONESIAN=66,
        ITALIAN_SWISS=67,
        JAPANESE=68,
        KOREAN=69,
        KOREAN_JOHAB=70,
        LATVIAN=71,
        LITHUANIAN=72,
        NORWEGIAN_BOKMAL=73,
        NORWEGIAN_NYNORSK=74,
        POLISH=75,
        PORTUGUESE_BRAZIL=76,
        ROMANIAN=77,
        RUSSIAN=78,
        SERBIAN_LATIN=79,
        SLOVAK=80,
        SLOVENIAN=81,
        SPANISH_MEXICAN=82,
        SPANISH_MODERN=83,
        THAI=84,
        TURKISH=85,
        UKRANIAN=86,
        /* More stuff added for 1.8 */
        ASSAMESE=87,
        BENGALI=88,
        BIHARI=89,
        BODO=90,
        DOGRI=91,
        GUJARATI=92,
        HARYANVI=93,
        HINDI=94,
        KANNADA=95,
        KASHMIRI=96,
        MALAYALAM=97,
        MARATHI=98,
        MARWARI=99,
        MEGHALAYAN=100,
        MIZO=101,
        NAGA=102,
        ORISSI=103,
        PUNJABI=104,
        PUSHTU=105,
        SERBIAN_CYRILLIC=106,
        SIKKIMI=107,
        SWEDISH_FINLAND=108,
        TAMIL=109,
        TELUGU=110,
        TRIPURI=111,
        URDU=112,
        VIETNAMESE=113
    }

    /// <summary>
    /// Country Constantsz
    /// </summary>
    public enum TwCountry:ushort {
        AFGHANISTAN=1001,
        ALGERIA=213,
        AMERICANSAMOA=684,
        ANDORRA=033,
        ANGOLA=1002,
        ANGUILLA=8090,
        ANTIGUA=8091,
        ARGENTINA=54,
        ARUBA=297,
        ASCENSIONI=247,
        AUSTRALIA=61,
        AUSTRIA=43,
        BAHAMAS=8092,
        BAHRAIN=973,
        BANGLADESH=880,
        BARBADOS=8093,
        BELGIUM=32,
        BELIZE=501,
        BENIN=229,
        BERMUDA=8094,
        BHUTAN=1003,
        BOLIVIA=591,
        BOTSWANA=267,
        BRITAIN=6,
        BRITVIRGINIS=8095,
        BRAZIL=55,
        BRUNEI=673,
        BULGARIA=359,
        BURKINAFASO=1004,
        BURMA=1005,
        BURUNDI=1006,
        CAMAROON=237,
        CANADA=2,
        CAPEVERDEIS=238,
        CAYMANIS=8096,
        CENTRALAFREP=1007,
        CHAD=1008,
        CHILE=56,
        CHINA=86,
        CHRISTMASIS=1009,
        COCOSIS=1009,
        COLOMBIA=57,
        COMOROS=1010,
        CONGO=1011,
        COOKIS=1012,
        COSTARICA=506,
        CUBA=005,
        CYPRUS=357,
        CZECHOSLOVAKIA=42,
        DENMARK=45,
        DJIBOUTI=1013,
        DOMINICA=8097,
        DOMINCANREP=8098,
        EASTERIS=1014,
        ECUADOR=593,
        EGYPT=20,
        ELSALVADOR=503,
        EQGUINEA=1015,
        ETHIOPIA=251,
        FALKLANDIS=1016,
        FAEROEIS=298,
        FIJIISLANDS=679,
        FINLAND=358,
        FRANCE=33,
        FRANTILLES=596,
        FRGUIANA=594,
        FRPOLYNEISA=689,
        FUTANAIS=1043,
        GABON=241,
        GAMBIA=220,
        GERMANY=49,
        GHANA=233,
        GIBRALTER=350,
        GREECE=30,
        GREENLAND=299,
        GRENADA=8099,
        GRENEDINES=8015,
        GUADELOUPE=590,
        GUAM=671,
        GUANTANAMOBAY=5399,
        GUATEMALA=502,
        GUINEA=224,
        GUINEABISSAU=1017,
        GUYANA=592,
        HAITI=509,
        HONDURAS=504,
        HONGKONG=852,
        HUNGARY=36,
        ICELAND=354,
        INDIA=91,
        INDONESIA=62,
        IRAN=98,
        IRAQ=964,
        IRELAND=353,
        ISRAEL=972,
        ITALY=39,
        IVORYCOAST=225,
        JAMAICA=8010,
        JAPAN=81,
        JORDAN=962,
        KENYA=254,
        KIRIBATI=1018,
        KOREA=82,
        KUWAIT=965,
        LAOS=1019,
        LEBANON=1020,
        LIBERIA=231,
        LIBYA=218,
        LIECHTENSTEIN=41,
        LUXENBOURG=352,
        MACAO=853,
        MADAGASCAR=1021,
        MALAWI=265,
        MALAYSIA=60,
        MALDIVES=960,
        MALI=1022,
        MALTA=356,
        MARSHALLIS=692,
        MAURITANIA=1023,
        MAURITIUS=230,
        MEXICO=3,
        MICRONESIA=691,
        MIQUELON=508,
        MONACO=33,
        MONGOLIA=1024,
        MONTSERRAT=8011,
        MOROCCO=212,
        MOZAMBIQUE=1025,
        NAMIBIA=264,
        NAURU=1026,
        NEPAL=977,
        NETHERLANDS=31,
        NETHANTILLES=599,
        NEVIS=8012,
        NEWCALEDONIA=687,
        NEWZEALAND=64,
        NICARAGUA=505,
        NIGER=227,
        NIGERIA=234,
        NIUE=1027,
        NORFOLKI=1028,
        NORWAY=47,
        OMAN=968,
        PAKISTAN=92,
        PALAU=1029,
        PANAMA=507,
        PARAGUAY=595,
        PERU=51,
        PHILLIPPINES=63,
        PITCAIRNIS=1030,
        PNEWGUINEA=675,
        POLAND=48,
        PORTUGAL=351,
        QATAR=974,
        REUNIONI=1031,
        ROMANIA=40,
        RWANDA=250,
        SAIPAN=670,
        SANMARINO=39,
        SAOTOME=1033,
        SAUDIARABIA=966,
        SENEGAL=221,
        SEYCHELLESIS=1034,
        SIERRALEONE=1035,
        SINGAPORE=65,
        SOLOMONIS=1036,
        SOMALI=1037,
        SOUTHAFRICA=27,
        SPAIN=34,
        SRILANKA=94,
        STHELENA=1032,
        STKITTS=8013,
        STLUCIA=8014,
        STPIERRE=508,
        STVINCENT=8015,
        SUDAN=1038,
        SURINAME=597,
        SWAZILAND=268,
        SWEDEN=46,
        SWITZERLAND=41,
        SYRIA=1039,
        TAIWAN=886,
        TANZANIA=255,
        THAILAND=66,
        TOBAGO=8016,
        TOGO=228,
        TONGAIS=676,
        TRINIDAD=8016,
        TUNISIA=216,
        TURKEY=90,
        TURKSCAICOS=8017,
        TUVALU=1040,
        UGANDA=256,
        USSR=7,
        UAEMIRATES=971,
        UNITEDKINGDOM=44,
        USA=1,
        URUGUAY=598,
        VANUATU=1041,
        VATICANCITY=39,
        VENEZUELA=58,
        WAKE=1042,
        WALLISIS=1043,
        WESTERNSAHARA=1044,
        WESTERNSAMOA=1045,
        YEMEN=1046,
        YUGOSLAVIA=38,
        ZAIRE=243,
        ZAMBIA=260,
        ZIMBABWE=263,
        /* Added for 1.8 */
        ALBANIA=355,
        ARMENIA=374,
        AZERBAIJAN=994,
        BELARUS=375,
        BOSNIAHERZGO=387,
        CAMBODIA=855,
        CROATIA=385,
        CZECHREPUBLIC=420,
        DIEGOGARCIA=246,
        ERITREA=291,
        ESTONIA=372,
        GEORGIA=995,
        LATVIA=371,
        LESOTHO=266,
        LITHUANIA=370,
        MACEDONIA=389,
        MAYOTTEIS=269,
        MOLDOVA=373,
        MYANMAR=95,
        NORTHKOREA=850,
        PUERTORICO=787,
        RUSSIA=7,
        SERBIA=381,
        SLOVAKIA=421,
        SLOVENIA=386,
        SOUTHKOREA=82,
        UKRAINE=380,
        USVIRGINIS=340,
        VIETNAM=84
    }

    /// <summary>
    /// Unit of measure
    /// </summary>
    public enum TwUnits:ushort { //ICAP_UNITS values (UN_ means UNits)
        Inches=0,
        Centimeters=1,
        Picas=2,
        Points=3,
        Twips=4,
        Pixels=5,
        Millimeters=6
    }

    /// <summary>
    /// Pixel types
    /// </summary>
    public enum TwPixelType:ushort { //ICAP_PIXELTYPE values (PT_ means Pixel Type)

        /// <summary>
        /// Black and white
        /// </summary>
        BW=0, /* Black and White */
        Gray=1,
        RGB=2,
        Palette=3,
        CMY=4,
        CMYK=5,
        YUV=6,
        YUVK=7,
        CIEXYZ=8,
        LAB=9,
        SRGB=10,
        SCRGB=11,
        INFRARED=16
    }

    /// <summary>
    /// Compression values
    /// </summary>
    public enum TwCompression:ushort { //ICAP_COMPRESSION values (CP_ means ComPression )
        None=0,
        PackBits=1,

        /// <summary>
        /// Follows CCITT spec (no End Of Line)
        /// </summary>
        Group31D=2,

        /// <summary>
        /// Follows CCITT spec (has End Of Line)
        /// </summary>
        Group31Deol=3,

        /// <summary>
        /// Follows CCITT spec (use cap for K Factor)
        /// </summary>
        Group32D=4,

        /// <summary>
        /// Follows CCITT spec
        /// </summary>
        Group4=5,

        /// <summary>
        /// Use capability for more info
        /// </summary>
        Jpeg=6,

        /// <summary>
        /// Must license from Unisys and IBM to use
        /// </summary>
        Lzw=7,

        /// <summary>
        /// For Bitonal images  -- Added 1.7 KHL
        /// </summary>
        Jbig=8,

        /* Added 1.8 */
        Png=9,
        Rle4=10,
        Rle8=11,
        BitFields=12,
        Zip=13,
        Jpeg2000=14
    }

    /// <summary>
    /// Extended Image Info Attributes.
    /// </summary>
    public enum TwEI:ushort { //TWEI_xxxx
        BarCodeX=0x1200,
        BarCodeY=0x1201,
        BarCodeText=0x1202,
        BarCodeType=0x1203,
        DeshadeTop=0x1204,
        DeshadeLeft=0x1205,
        DeshadeHeight=0x1206,
        DeshadeWidth=0x1207,
        DeshadeSize=0x1208,
        SpecklesRemoved=0x1209,
        HorzLineXCoord=0x120A,
        HorzLineYCoord=0x120B,
        HorzLineLength=0x120C,
        HorzLineThickness=0x120D,
        VertLineXCoord=0x120E,
        VertLinEYCoord=0x120F,
        VertLineLength=0x1210,
        VertLineThickness=0x1211,
        PatchCode=0x1212,
        EndOrSedText=0x1213,
        FormConfidence=0x1214,
        FormTemplateMatch=0x1215,
        FormTemplatePageMatch=0x1216,
        FormHorzDocOffset=0x1217,
        FormVertDocOffset=0x1218,
        BarCodeCount=0x1219,
        BarCodeConfidence=0x121A,
        BarCodeRotation=0x121B,
        BarCodeTextLength=0x121C,
        DeshadeCount=0x121D,
        DeshadeBlackCountOld=0x121E,
        DeshadeBlackCountNew=0x121F,
        DeshadeBlackRLMin=0x1220,
        DeshadeBlackRLMax=0x1221,
        DeshadeWhiteCountOld=0x1222,
        DeshadeWhiteCountNew=0x1223,
        DeshadeWhiteRLMin=0x1224,
        DeshadeWhiteRLAve=0x1225,
        DeshadeWhiteRLMax=0x1226,
        BlackSpecklesRemoved=0x1227,
        WhiteSpecklesRemoved=0x1228,
        HorzLineCount=0x1229,
        VertLineCount=0x122A,
        DeskewStatus=0x122B,
        SkewOriginalAngle=0x122C,
        SkewFinalAngle=0x122D,
        SkewConfidence=0x122E,
        SkewWindowX1=0x122F,
        SkewWindowY1=0x1230,
        SkewWindowX2=0x1231,
        SkewWindowY2=0x1232,
        SkewWindowX3=0x1233,
        SkewWindowY3=0x1234,
        SkewWindowX4=0x1235,
        SkewWindowY4=0x1236,
        BookName=0x1238,  /* added 1.9 */
        ChapterNumber=0x1239,  /* added 1.9 */
        DocumentNumber=0x123A,  /* added 1.9 */
        PageNumber=0x123B,  /* added 1.9 */
        Camera=0x123C,  /* added 1.9 */
        FrameNumber=0x123D,  /* added 1.9 */
        Frame=0x123E,  /* added 1.9 */
        PixelFlavor=0x123F,  /* added 1.9 */
        IccProFile=0x1240,  /* added 1.91 */
        LastSegment=0x1241,  /* added 1.91 */
        SegmentNumber=0x1242,  /* added 1.91 */
        MagData=0x1243,  /* added 2.0 */
        MagType=0x1244,  /* added 2.0 */
        PageSide=0x1245,
        FileSystemSource=0x1246,
        ImageMerged=0x1247,
        MagDataLength=0x1248,
        PaperCount=0x1249,
        PrinterText=0x124A
    }

    /// <summary>
    /// ICAP_XFERMECH values (SX_ means Setup XFer)
    /// </summary>
    public enum TwSX:ushort {
        Native=0,
        File=1,
        Memory=2,
        MemFile=4    /* added 1.91 */
    }

    /// <summary>
    /// Flags used in TW_MEMORY structure.
    /// </summary>
    [Flags]
    internal enum TwMF:uint {
        AppOwns=0x1,
        DsmOwns=0x2,
        DSOwns=0x4,
        Pointer=0x8,
        Handle=0x10
    }

    /// <summary>
    /// ICAP_SUPPORTEDSIZES values (SS_ means Supported Sizes).
    /// </summary>
    public enum TwSS:ushort {
        None=0,
        A4Letter=1,
        B5Letter=2,
        USLetter=3,
        USLegal=4,
        /* Added 1.5 */
        A5=5,
        B4=6,
        B6=7,
        /* Added 1.7 */
        USLedger=9,
        USExecutive=10,
        A3=11,
        B3=12,
        A6=13,
        C4=14,
        C5=15,
        C6=16,
        /* Added 1.8 */
        _4A0=17,
        _2A0=18,
        A0=19,
        A1=20,
        A2=21,
        A4=A4Letter,
        A7=22,
        A8=23,
        A9=24,
        A10=25,
        ISOB0=26,
        ISOB1=27,
        ISOB2=28,
        ISOB3=B3,
        ISOB4=B4,
        ISOB5=29,
        ISOB6=B6,
        ISOB7=30,
        ISOB8=31,
        ISOB9=32,
        ISOB10=33,
        JISB0=34,
        JISB1=35,
        JISB2=36,
        JISB3=37,
        JISB4=38,
        JISB5=B5Letter,
        JISB6=39,
        JISB7=40,
        JISB8=41,
        JISB9=42,
        JISB10=43,
        C0=44,
        C1=45,
        C2=46,
        C3=47,
        C7=48,
        C8=49,
        C9=50,
        C10=51,
        USStatement=52,
        BusinessCard=53
    }

    /// <summary>
    /// ICAP_IMAGEFILEFORMAT values (FF_means File Format).
    /// </summary>
    public enum TwFF:ushort {

        /// <summary>
        /// Tagged Image File Format.
        /// </summary>
        Tiff=0,

        /// <summary>
        /// Macintosh PICT.
        /// </summary>
        Pict=1,

        /// <summary>
        /// Windows Bitmap.
        /// </summary>
        Bmp=2,

        /// <summary>
        /// X-Windows Bitmap.
        /// </summary>
        Xbm=3,

        /// <summary>
        /// Jpeg File Interchange Format.
        /// </summary>
        Jfif=4,

        /// <summary>
        /// Flash Pix.
        /// </summary>
        Fpx=5,

        /// <summary>
        /// Multi-page tiff file.
        /// </summary>
        TiffMulti=6,

        Png=7,
        Spiff=8,
        Exif=9,

        /// <summary>
        /// 1.91 NB: this is not PDF/A
        /// </summary>
        Pdf=10,

        /// <summary>
        /// 1.91
        /// </summary>
        Jp2=11,

        /// <summary>
        /// 1.91
        /// </summary>
        Jpx=13,

        /// <summary>
        /// 1.91
        /// </summary>
        Dejavu=14,

        /// <summary>
        /// 2.0 Adobe PDF/A, Version 1.
        /// </summary>
        PdfA=15,

        /// <summary>
        /// 2.1 Adobe PDF/A, Version.
        /// </summary>
        PdfA2=16
    }

    /// <summary>
    /// Palette types for TW_PALETTE8.
    /// </summary>
    public enum TwPA:ushort {
        RGB=0,
        Gray=1,
        CMY=2
    }

    /// <summary>
    /// CAP_DEVICEEVENT values (DE_ means device event).
    /// </summary>
    public enum TwDE:ushort {
        CustomEvents=0x8000,
        CheckAutomaticCapture=0,
        CheckBattery=1,
        CheckDeviceOnline=2,
        CheckFlash=3,
        CheckPowerSupply=4,
        CheckResolution=5,
        DeviceAdded=6,
        DeviceOffline=7,
        DeviceReady=8,
        DeviceRemoved=9,
        ImageCaptured=10,
        ImageDeleted=11,
        PaperDoubleFeed=12,
        PaperJam=13,
        LampFailure=14,
        PowerSave=15,
        PowerSaveNotify=16
    }

    /// <summary>
    /// ICAP_DUPLEX values.
    /// </summary>
    public enum TwDX:ushort {
        None=0,          // TWDX_NONE
        OnePassDuplex=1, // TWDX_1PASSDUPLEX
        TwoPassDuplex=2  // TWDX_2PASSDUPLEX
    }

    /// <summary>
    /// ICAP_AUTODISCARDBLANKPAGES values.
    /// </summary>
    public enum TwBP:int {
        Disable=-2, // TWBP_DISABLE
        Auto=-1  // TWBP_AUTO
    }

    /// <summary>
    /// ICAP_AUTOSIZE values.
    /// </summary>
    public enum TwAS:ushort {
        None=0,
        Auto=1,
        Current=2
    }

    /// <summary>
    /// ICAP_FLIPROTATION values (FR_ means flip rotation).
    /// </summary>
    public enum TwFR:ushort {
        Book=0,
        Fanfold=1
    }

    /// <summary>
    /// ICAP_IMAGEMERGE values.
    /// </summary>
    public enum TwIM:ushort {
        None=0,
        FrontOnTop=1,
        FrontOnBottom=2,
        FrontOnLeft=3,
        FrontOnRight=4
    }

    /// <summary>
    /// CAP_CAMERASIDE and TWEI_PAGESIDE values.
    /// </summary>
    public enum TwCS:ushort {
        Both=0,
        Top=1,
        Bottom=2
    }

    /// <summary>
    /// CAP_CLEARBUFFERS values.
    /// </summary>
    public enum TwCB:ushort {
        Auto=0,
        Clear=1,
        NoClear=2
    }

    /// <summary>
    /// ICAP_SUPPORTEDBARCODETYPES and TWEI_BARCODETYPE values.
    /// </summary>
    public enum TwBT:ushort {
        Code3Of9=0,
        Code2Of5Interleaved=1,
        Code2Of5NonInterleaved=2,
        Code93=3,
        Code128=4,
        Ucc128=5,
        CodaBar=6,
        Upca=7,
        Upce=8,
        Ean8=9,
        Ean13=10,
        PostNet=11,
        Pdf417=12,
        Code2Of5Industrial=13,
        Code2Of5Matrix=14,
        Code2Of5DataLogic=15,
        Code2Of5Iata=16,
        Code3Of9FullAscii=17,
        CodaBarWithStartStop=18,
        MaxiCode=19,
        QRCode=20
    }

    /// <summary>
    /// ICAP_BARCODESEARCHMODE values.
    /// </summary>
    public enum TwBD:ushort {
        Horz=0,
        Vert=1,
        HorzVert=2,
        VertHorz=3
    }

    /// <summary>
    /// ICAP_FILTER values.
    /// </summary>
    public enum TwFT:ushort {
        Red=0,
        Green=1,
        Blue=2,
        None=3,
        White=4,
        Cyan=5,
        Magenta=6,
        Yellow=7,
        Black=8
    }

    /// <summary>
    /// ICAP_ICCPROFILE values.
    /// </summary>
    public enum TwIC:ushort {
        None=0,
        Link=1,
        Embed=2
    }

    /// <summary>
    /// ICAP_PLANARCHUNKY values.
    /// </summary>
    public enum TwPC:ushort {
        Chunky=0,
        Planar=1
    }

    /// <summary>
    /// ICAP_BITORDER values.
    /// </summary>
    public enum TwBO:ushort {
        LsbFirst=0,
        MsbFirst=1
    }

    /// <summary>
    /// ICAP_JPEGQUALITY values.
    /// </summary>
    public enum TwJQ:short {
        Unknown=-4,
        Low=-3,
        Medium=-2,
        High=-1
    }

    /// <summary>
    /// ICAP_JPEGSUBSAMPLING values.
    /// </summary>
    public enum TwJS:ushort {
        _444Ycbcr=0,
        _444Rgb=1,
        _422=2,
        _421=3,
        _411=4,
        _420=5,
        _410=6,
        _311=7
    }

    /// <summary>
    /// ICAP_PIXELFLAVOR values.
    /// </summary>
    public enum TwPF:ushort {
        Chocolate=0,
        Vanilla=1
    }

    /// <summary>
    /// ICAP_FLASHUSED2 values.
    /// </summary>
    public enum TwFL:ushort {
        None=0,
        Off=1,
        On=2,
        Auto=3,
        RedEye=4
    }

    /// <summary>
    /// ICAP_IMAGEFILTER values.
    /// </summary>
    public enum TwIF:ushort {
        None=0,
        Auto=1,
        LowPass=2,
        BandPass=3,
        HighPass=4,
        Text=BandPass,
        FineLine=HighPass
    }

    /// <summary>
    /// ICAP_LIGHTPATH values.
    /// </summary>
    public enum TwLP:ushort {
        Reflective=0,
        Transmissive=1
    }

    /// <summary>
    /// ICAP_LIGHTSOURCE values.
    /// </summary>
    public enum TwLS:ushort {
        Red=0,
        Green=1,
        Blue=2,
        None=3,
        White=4,
        UV=5,
        IR=6
    }

    /// <summary>
    /// ICAP_NOISEFILTER values.
    /// </summary>
    public enum TwNF:ushort {
        None=0,
        Auto=1,
        LonePixel=2,
        MajorityRule=3
    }

    /// <summary>
    /// ICAP_OVERSCAN values.
    /// </summary>
    public enum TwOV:ushort {
        None=0,
        Auto=1,
        TopBottom=2,
        LeftRight=3,
        All=4
    }

    /// <summary>
    /// CAP_DOUBLEFEEDDETECTION.
    /// </summary>
    public enum TwDF:ushort {
        Ultrasonic=0,
        ByLength=1,
        Infrared=2
    }

    /// <summary>
    /// CAP_DOUBLEFEEDDETECTIONSENSITIVITY.
    /// </summary>
    public enum TwUS:ushort {
        Low=0,
        Medium=1,
        High=2
    }

    /// <summary>
    /// CAP_DOUBLEFEEDDETECTIONRESPONSE.
    /// </summary>
    public enum TwDP:ushort {
        Stop=0,
        StopAndWait=1,
        Sound=2,
        DoNotImprint=3
    }

    /// <summary>
    /// CAP_PRINTER values.
    /// </summary>
    public enum TwPR:ushort {
        ImprinterTopBefore=0,
        ImprinterTopAfter=1,
        ImprinterBottomBefore=2,
        ImprinterBottomAfter=3,
        EndorserTopBefore=4,
        EndorserTopAfter=5,
        EndorserBottomBefore=6,
        EndorserBottomAfter=7
    }

    /// <summary>
    /// CAP_PRINTERMODE values.
    /// </summary>
    public enum TwPM:ushort {
        SingleString=0,
        MultiString=1,
        CompoundString=2
    }

    /// <summary>
    /// ICAP_ORIENTATION values.
    /// </summary>
    public enum TwOR:ushort {
        Rot0=0,
        Rot90=1,
        Rot180=2,
        Rot270=3,
        Portrait=Rot0,
        Landscape=Rot270,
        Auto=4,
        AutoText=5,
        AutoPicture=6
    }

    /// <summary>
    /// ICAP_BITDEPTHREDUCTION values.
    /// </summary>
    public enum TwBR:ushort {
        Threshold=0,
        Halftone=1,
        CustHalftone=2,
        Diffusion=3,
        DynamicThreshold=4
    }

    /// <summary>
    /// CAP_SEGMENTED values.
    /// </summary>
    public enum TwSG:ushort {
        None=0,
        Auto=1,
        Manual=2
    }

    /// <summary>
    /// CAP_FEEDERALIGNMENT values.
    /// </summary>
    public enum TwFA:ushort {
        None=0,
        Left=1,
        Center=2,
        Right=3
    }

    /// <summary>
    /// CAP_FEEDERORDER values.
    /// </summary>
    public enum TwFO:ushort {
        FirstPageFirst=0,
        LastPageFirst=1
    }

    /// <summary>
    /// CAP_FEEDERPOCKET values.
    /// </summary>
    public enum TwFP:ushort {
        PocketError=0,
        Pocket1=1,
        Pocket2=2,
        Pocket3=3,
        Pocket4=4,
        Pocket5=5,
        Pocket6=6,
        Pocket7=7,
        Pocket8=8,
        Pocket9=9,
        Pocket10=10,
        Pocket11=11,
        Pocket12=12,
        Pocket13=13,
        Pocket14=14,
        Pocket15=15,
        Pocket16=16
    }

    /// <summary>
    /// CAP_PAPERHANDLING values.
    /// </summary>
    public enum TwPH:ushort {
        Normal=0,
        Fragile=1,
        Thick=2,
        Trifold=3,
        Photograph=4
    }

    /// <summary>
    /// ICAP_FEEDERTYPE values.
    /// </summary>
    public enum TwFE:ushort {
        General=0,
        Photo=1,
    }

    /// <summary>
    /// TWEI_PATCHCODE values.
    /// </summary>
    public enum TwPch:ushort {
        Patch1=0,
        Patch2=1,
        Patch3=2,
        Patch4=3,
        Patch6=4,
        PatchT=5
    }

    /// <summary>
    /// CAP_BATTERYMINUTES values.
    /// </summary>
    public enum TwBM1:int {
        Infinite=-2,
        CannotReport=-1
    }

    /// <summary>
    /// CAP_BATTERYPERCENTAGE values.
    /// </summary>
    public enum TwBM2:short {
        Infinite=-2,
        CannotReport=-1
    }

    /// <summary>
    /// CAP_POWERSUPPLY values.
    /// </summary>
    public enum TwPS:ushort {
        External=0,
        Battery=1
    }

    /// <summary>
    /// CAP_JOBCONTROL values.
    /// </summary>
    public enum TwJC:ushort {
        None=0,
        Jsic=1,
        Jsis=2,
        Jsxc=3,
        Jsxs=4
    }

    /// <summary>
    /// CAP_INDICATORSMODE values.
    /// </summary>
    public enum TwCI:ushort {
        Info=0,
        Warning=1,
        Error=2,
        WarmUp=3
    }

    /// <summary>
    /// CAP_ALARMS values.
    /// </summary>
    public enum TwAL:ushort {
        Alarm=0,
        FeederError=1,
        FeederWarning=2,
        BarCode=3,
        DoubleFeed=4,
        Jam=5,
        PatchCode=6,
        Power=7,
        Skew=8
    }

    #endregion

    #region Type Definitions

    /// <summary>
    /// Строка фиксированной длинны 32 символа.
    /// </summary>
    [DebuggerDisplay("{Value}")]
    [StructLayout(LayoutKind.Sequential, Pack=2, CharSet=CharSet.Ansi)]
    internal sealed class TwStr32 {

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst=34)]
        public string Value;

        public override string ToString() {
            return this.Value;
        }

        public static implicit operator string(TwStr32 value) {
            return value!=null?value.Value:null;
        }

        public static implicit operator TwStr32(string value) {
            return new TwStr32 {
                Value=value
            };
        }
    }

    /// <summary>
    /// Строка фиксированной длинны 64 символа.
    /// </summary>
    [DebuggerDisplay("{Value}")]
    [StructLayout(LayoutKind.Sequential, Pack=2, CharSet=CharSet.Ansi)]
    internal sealed class TwStr64 {

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst=66)]
        public string Value;

        public override string ToString() {
            return this.Value;
        }

        public static implicit operator string(TwStr64 value) {
            return value!=null?value.Value:null;
        }

        public static implicit operator TwStr64(string value) {
            return new TwStr64 {
                Value=value
            };
        }
    }

    /// <summary>
    /// Строка фиксированной длинны 128 символов.
    /// </summary>
    [DebuggerDisplay("{Value}")]
    [StructLayout(LayoutKind.Sequential, Pack=2, CharSet=CharSet.Ansi)]
    internal sealed class TwStr128 {

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst=130)]
        public string Value;

        public override string ToString() {
            return this.Value;
        }

        public static implicit operator string(TwStr128 value) {
            return value!=null?value.Value:null;
        }

        public static implicit operator TwStr128(string value) {
            return new TwStr128 {
                Value=value
            };
        }
    }

    /// <summary>
    /// Строка фиксированной длинны 255 символов.
    /// </summary>
    [DebuggerDisplay("{Value}")]
    [StructLayout(LayoutKind.Sequential, Pack=2, CharSet=CharSet.Ansi)]
    internal sealed class TwStr255 {

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst=256)]
        public string Value;

        public override string ToString() {
            return this.Value;
        }

        public static implicit operator string(TwStr255 value) {
            return value!=null?value.Value:null;
        }

        public static implicit operator TwStr255(string value) {
            return new TwStr255 {
                Value=value
            };
        }
    }

    /// <summary>
    /// Строка юникода фиксированной длинны 512 символов.
    /// </summary>
    [DebuggerDisplay("{Value}")]
    [StructLayout(LayoutKind.Sequential, Pack=2, CharSet=CharSet.Unicode)]
    internal sealed class TwUni512 {

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst=512)]
        public string Value;

        public override string ToString() {
            return this.Value;
        }

        public static implicit operator string(TwUni512 value) {
            return value!=null?value.Value:null;
        }

        public static implicit operator TwUni512(string value) {
            return new TwUni512 {
                Value=value
            };
        }
    }

    /// <summary>
    /// Строка фиксированной длинны 1024 символов.
    /// </summary>
    [DebuggerDisplay("{Value}")]
    [StructLayout(LayoutKind.Sequential, Pack=2, CharSet=CharSet.Ansi)]
    internal sealed class TwStr1024 {

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst=1026)]
        public string Value;

        public override string ToString() {
            return this.Value;
        }

        public static implicit operator string(TwStr1024 value) {
            return value!=null?value.Value:null;
        }

        public static implicit operator TwStr1024(string value) {
            return new TwStr1024 {
                Value=value
            };
        }
    }

    /// <summary>
    /// Boolean value.
    /// </summary>
    [DebuggerDisplay("{ToBool()}")]
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal struct TwBool {

        public ushort Value;

        private bool ToBool() {
            return this.Value!=0;
        }

        public static implicit operator bool(TwBool value) {
            return value.ToBool();
        }

        public static implicit operator TwBool(bool value) {
            return new TwBool {
                Value=(ushort)(value?1:0)
            };
        }
    }

    /// <summary>
    /// Fixed point structure type.
    /// </summary>
    [DebuggerDisplay("{ToFloat()}")]
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal struct TwFix32 {									// TW_FIX32

        /// <summary>
        /// Целая часть.
        /// </summary>
        public short Whole;

        /// <summary>
        /// Дробная часть.
        /// </summary>
        public ushort Frac;

        /// <summary>
        /// Приводит тип к числу с плавающей запятой.
        /// </summary>
        /// <returns>Число с плавающей точкой.</returns>
        private float ToFloat() {
            return (float)this.Whole+((float)this.Frac/65536.0f);
        }

        /// <summary>
        /// Создает экземпляр TwFix32 из числа с плавающей точкой.
        /// </summary>
        /// <param name="f">Число с плавающей точкой.</param>
        /// <returns>Экземпляр TwFix32.</returns>
        public static implicit operator TwFix32(float f) {
            int i=(int)((f*65536.0f)+0.5f);
            return new TwFix32() {
                Whole=(short)(i>>16),
                Frac=(ushort)(i&0x0000ffff)
            };
        }

        /// <summary>
        /// Создает экземпляр TwFix32 из целого числа.
        /// </summary>
        /// <param name="f">Целое число.</param>
        /// <returns>Экземпляр TwFix32.</returns>
        public static explicit operator TwFix32(uint value) {
            return new TwFix32() {
                Whole=(short)(value&0x0000ffff),
                Frac=(ushort)(value>>16)
            };
        }

        /// <summary>
        /// Приводит тип к числу с плавающей запятой.
        /// </summary>
        /// <param name="value">Экземпляр TwFix32.</param>
        /// <returns>Число с плавающей точкой.</returns>
        public static implicit operator float(TwFix32 value) {
            return value.ToFloat();
        }

        /// <summary>
        /// Приводит тип к целому числу.
        /// </summary>
        /// <param name="value">Экземпляр TwFix32.</param>
        /// <returns>Целое число.</returns>
        public static explicit operator uint(TwFix32 value) {
            return (uint)(ushort)value.Whole+((uint)value.Frac<<16);
        }
    }

    /// <summary>
    /// Defines a frame rectangle in ICAP_UNITS coordinates.
    /// </summary>
    [DebuggerDisplay("{ToRectangle()}")]
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal struct TwFrame {

        /// <summary>
        /// Gets or sets the x-coordinate of the left edge.
        /// </summary>
        public TwFix32 Left;

        /// <summary>
        /// Gets or sets the y-coordinate of the top edge.
        /// </summary>
        public TwFix32 Top;

        /// <summary>
        /// Gets or sets the x-coordinate that is the sum of TwFrame.Left and width of image.
        /// </summary>
        public TwFix32 Right;

        /// <summary>
        /// Gets or sets the y-coordinate that is the sum of TwFrame.Top and length of image.
        /// </summary>
        public TwFix32 Bottom;

        private RectangleF ToRectangle() {
            return new RectangleF(
                this.Left,
                this.Top,
                this.Right-this.Left,
                this.Bottom-this.Top);
        }

        public static implicit operator RectangleF(TwFrame value) {
            return value.ToRectangle();
        }

        public static implicit operator TwFrame(RectangleF value) {
            return new TwFrame() {
                Left=value.Left,
                Top=value.Top,
                Right=value.Right,
                Bottom=value.Bottom
            };
        }
    }

    #endregion

    #region Structure Definitions

    /// <summary>
    /// Identifies the program/library/code resource.
    /// </summary>
    [DebuggerDisplay("{ProductName}, Version = {Version.Info}")]
    [StructLayout(LayoutKind.Sequential, Pack=2, CharSet=CharSet.Ansi)]
    public sealed class TwIdentity {									// TW_IDENTITY
        private uint _id;
        private TwVersion _version;
        private ushort _protocolMajor;
        private ushort _protocolMinor;

        [MarshalAs(UnmanagedType.U4)]
        private TwDG _supportedGroups;
        private TwStr32 _manufacturer;
        private TwStr32 _productFamily;
        private TwStr32 _productName;

        private TwIdentity() {
        }

        internal TwIdentity(uint id, TwVersion version, ushort protocolMajor, ushort protocolMinor, TwDG supportedGroups, TwStr32 manufacturer, TwStr32 productFamily, TwStr32 productName) {
            this._id=id;
            this._version=version;
            this._protocolMajor=protocolMajor;
            this._protocolMinor=protocolMinor;
            this._supportedGroups=supportedGroups;
            this._manufacturer=manufacturer;
            this._productFamily=productFamily;
            this._productName=productName;
        }

        /// <summary>
        /// Unique number.  In Windows, appId hWnd.
        /// </summary>
        internal uint Id {
            get {
                return this._id;
            }
        }

        /// <summary>
        /// Identifies the piece of code
        /// </summary>
        internal TwVersion Version {
            get {
                return this._version;
            }
        }

        /// <summary>
        /// Application and DS must set to TWON_PROTOCOLMAJOR
        /// </summary>
        internal ushort ProtocolMajor {
            get {
                return this._protocolMajor;
            }
        }

        /// <summary>
        /// Application and DS must set to TWON_PROTOCOLMINOR
        /// </summary>
        internal ushort ProtocolMinor {
            get {
                return this._protocolMinor;
            }
        }

        /// <summary>
        /// Bit field OR combination of DG_ constants
        /// </summary>
        internal TwDG SupportedGroups {
            get {
                return this._supportedGroups;
            }
        }

        /// <summary>
        /// Manufacturer name, e.g. "Hewlett-Packard"
        /// </summary>
        internal TwStr32 Manufacturer {
            get {
                return this._manufacturer;
            }
        }

        /// <summary>
        /// Product family name, e.g. "ScanJet"
        /// </summary>
        internal TwStr32 ProductFamily {
            get {
                return this._productFamily;
            }
        }

        /// <summary>
        /// Product name, e.g. "ScanJet Plus"
        /// </summary>
        internal TwStr32 ProductName {
            get {
                return this._productName;
            }
        }

        public override bool Equals(object obj) {
            if(obj!=null&&obj is TwIdentity) {
                return ((TwIdentity)obj).Id==this.Id;
            }
            return false;
        }

        public override int GetHashCode() {
            return this.Id.GetHashCode();
        }
    }

    /// <summary>
    /// Describes version of software currently running.
    /// </summary>
    [DebuggerDisplay("{Info}")]
    [StructLayout(LayoutKind.Sequential, Pack=2, CharSet=CharSet.Ansi)]
    internal struct TwVersion {									// TW_VERSION
        private ushort _majorNum;
        private ushort _minorNum;

        [MarshalAs(UnmanagedType.U2)]
        private TwLanguage _language;

        [MarshalAs(UnmanagedType.U2)]
        private TwCountry _country;
        private TwStr32 _info;

        internal TwVersion(ushort majorNum, ushort minorNum, TwLanguage language, TwCountry country, TwStr32 info) {
            this._majorNum=majorNum;
            this._minorNum=minorNum;
            this._language=language;
            this._country=country;
            this._info=info;
        }

        /// <summary>
        /// Major revision number of the software.
        /// </summary>
        public ushort MajorNum {
            get {
                return this._majorNum;
            }
        }

        /// <summary>
        /// Incremental revision number of the software.
        /// </summary>
        public ushort MinorNum {
            get {
                return this._minorNum;
            }
        }

        /// <summary>
        /// e.g. TWLG_SWISSFRENCH
        /// </summary>
        public TwLanguage Language {
            get {
                return this._language;
            }
        }

        /// <summary>
        /// e.g. TWCY_SWITZERLAND
        /// </summary>
        public TwCountry Country {
            get {
                return this._country;
            }
        }

        /// <summary>
        /// e.g. "1.0b3 Beta release"
        /// </summary>
        public TwStr32 Info {
            get {
                return this._info;
            }
        }
    }

    /// <summary>
    /// Coordinates UI between appId and entry source.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwUserInterface {						    // TW_USERINTERFACE

        /// <summary>
        /// TRUE if DS should bring up its UI
        /// </summary>
        public TwBool ShowUI;				// bool is strictly 32 bit, so use short

        /// <summary>
        /// For Mac only - true if the DS's UI is modal
        /// </summary>
        public TwBool ModalUI;

        /// <summary>
        /// For windows only - Application window handle
        /// </summary>
        public IntPtr ParentHand;
    }

    /// <summary>
    /// Application gets detailed status info from a entry source with this.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwStatus {									// TW_STATUS

        /// <summary>
        /// Any TwCC constant
        /// </summary>
        [MarshalAs(UnmanagedType.U2)]
        public TwCC ConditionCode;		// TwCC

        /// <summary>
        /// Future expansion space
        /// </summary>
        public ushort Reserved;
    }

    /// <summary>
    /// For passing events down from the appId to the DS.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwEvent {									// TW_EVENT

        /// <summary>
        /// Windows pMSG or Mac pEvent.
        /// </summary>
        public IntPtr EventPtr;

        /// <summary>
        /// TwMSG from entry source, e.g. TwMSG.XFerReady
        /// </summary>
        [MarshalAs(UnmanagedType.U2)]
        public TwMSG Message;
    }

    /// <summary>
    /// Application gets detailed image info from DS with this.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwImageInfo {								// TW_IMAGEINFO

        /// <summary>
        /// Resolution in the horizontal
        /// </summary>
        public TwFix32 XResolution;

        /// <summary>
        /// Resolution in the vertical
        /// </summary>
        public TwFix32 YResolution;

        /// <summary>
        /// Columns in the image, -1 if unknown by DS
        /// </summary>
        public int ImageWidth;

        /// <summary>
        /// Rows in the image, -1 if unknown by DS
        /// </summary>
        public int ImageLength;

        /// <summary>
        /// Number of samples per pixel, 3 for RGB
        /// </summary>
        public short SamplesPerPixel;

        /// <summary>
        /// Number of bits for each sample
        /// </summary>
        [MarshalAs(UnmanagedType.ByValArray, SizeConst=8)]
        public short[] BitsPerSample;

        /// <summary>
        /// Number of bits for each padded pixel
        /// </summary>
        public short BitsPerPixel;

        /// <summary>
        /// True if Planar, False if chunky
        /// </summary>
        public TwBool Planar;

        /// <summary>
        /// How to interp entry; photo interp
        /// </summary>
        [MarshalAs(UnmanagedType.U2)]
        public TwPixelType PixelType;

        /// <summary>
        /// How the entry is compressed
        /// </summary>
        [MarshalAs(UnmanagedType.U2)]
        public TwCompression Compression;
    }

    /// <summary>
    /// This structure is used to pass specific information between the entry source and the appId.
    /// </summary>
    //[DebuggerDisplay("InfoId = {InfoId}, ItemType = {ItemType}, ReturnCode = {ReturnCode}")]
    //[StructLayout(LayoutKind.Sequential, Pack=2)]
    //internal class TwInfo:IDisposable {

    //    /// <summary>
    //    /// Tag identifying an information.
    //    /// </summary>
    //    [MarshalAs(UnmanagedType.U2)]
    //    public TwEI InfoId;

    //    /// <summary>
    //    /// Item entry type.
    //    /// </summary>
    //    [MarshalAs(UnmanagedType.U2)]
    //    public TwType ItemType;

    //    /// <summary>
    //    /// Number of items for this field.
    //    /// </summary>
    //    public ushort NumItems;

    //    /// <summary>
    //    /// This is the return code of availability of entry for extended image attribute requested.
    //    /// </summary>
    //    [MarshalAs(UnmanagedType.U2)]
    //    public TwRC ReturnCode;

    //    /// <summary>
    //    /// Contains either entry or a handle to entry.
    //    /// </summary>
    //    public IntPtr Item;

    //    /// <summary>
    //    /// Возвращает true, если значение элемента является дескриптором неуправляемой памяти; иначе, false.
    //    /// </summary>
    //    private bool _IsValue {
    //        get {
    //            return this.ItemType!=TwType.Handle&&TwTypeHelper.SizeOf(this.ItemType)*this.NumItems<=TwTypeHelper.SizeOf(TwType.Handle);
    //        }
    //    }

    //    /// <summary>
    //    /// Возвращает значение элемента.
    //    /// </summary>
    //    /// <returns>Значение элемента.</returns>
    //    public object Value() {
    //        var _result=new object[this.NumItems];
    //        if(this._IsValue) {
    //            for(long i=0, _data=this.Item.ToInt64(), _mask=((1L<<TwTypeHelper.SizeOf(this.ItemType)*7)<<TwTypeHelper.SizeOf(this.ItemType))-1; i<this.NumItems; i++, _data>>=TwTypeHelper.SizeOf(this.ItemType)*8) {
    //                _result[i]=TwTypeHelper.CastToCommon(this.ItemType, TwTypeHelper.ValueToTw<long>(this.ItemType, _data&_mask));
    //            }
    //        } else {
    //            IntPtr _data=Twain32._Memory.Lock(this.Item);
    //            try {
    //                for(int i=0; i<this.NumItems; i++) {
    //                    if(this.ItemType!=TwType.Handle) {
    //                        _result[i]=TwTypeHelper.CastToCommon(this.ItemType, Marshal.PtrToStructure((IntPtr)((long)_data+(TwTypeHelper.SizeOf(this.ItemType)*i)), TwTypeHelper.TypeOf(this.ItemType)));
    //                    } else {
    //                        _result[i]=Marshal.PtrToStringAnsi(_data);
    //                        _data=(IntPtr)((long)_data+_result[i].ToString().Length+1);
    //                    }
    //                }
    //            } finally {
    //                Twain32._Memory.Unlock(this.Item);
    //            }
    //        }
    //        return _result.Length==1?_result[0]:_result;
    //    }

    //    #region IDisposable

    //    public void Dispose() {
    //        if(this.Item!=IntPtr.Zero&&!this._IsValue) {
    //            Twain32._Memory.Free(this.Item);
    //            this.Item=IntPtr.Zero;
    //        }
    //    }

    //    #endregion
    //}

    /// <summary>
    /// This structure is used to pass extended image information from the Data Source to the Application at the end of State 7.
    /// </summary>
    //[StructLayout(LayoutKind.Sequential, Pack=2)]
    //internal class TwExtImageInfo {

    //    /// <summary>
    //    /// Количество элементов расширенного описания изображения.
    //    /// </summary>
    //    public uint NumInfos;

    //    //[MarshalAs(UnmanagedType.ByValArray,SizeConst=1)]
    //    //public TwInfo[] Info;

    //    /// <summary>
    //    /// Выполняет преображование в неуправляемый блок памяти.
    //    /// </summary>
    //    /// <param name="info">Набор элементов расширенного описания изображения.</param>
    //    /// <returns>Указатель на блок неуправляемой памяти.</returns>
    //    public static IntPtr ToPtr(TwInfo[] info) {
    //        var _twExtImageInfoSize=Marshal.SizeOf(typeof(TwExtImageInfo));
    //        var _twInfoSize=Marshal.SizeOf(typeof(TwInfo));
    //        var _data=Marshal.AllocHGlobal(_twExtImageInfoSize+(_twInfoSize*info.Length));
    //        Marshal.StructureToPtr(new TwExtImageInfo {
    //            NumInfos=(uint)info.Length
    //        }, _data, true);
    //        for(int i=0; i<info.Length; i++) {
    //            Marshal.StructureToPtr(info[i], (IntPtr)(_data.ToInt64()+_twExtImageInfoSize+(_twInfoSize*i)), true);
    //        }
    //        return _data;
    //    }
    //}

    /// <summary>
    /// Provides image layout information in current units.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwImageLayout {

        /// <summary>
        /// Frame coords within larger document.
        /// </summary>
        public TwFrame Frame;

        /// <summary>
        /// Номер документа.
        /// </summary>
        public uint DocumentNumber;

        /// <summary>
        /// Номер страницы.
        /// </summary>
        public uint PageNumber; //Reset when you go to next document

        /// <summary>
        /// Номер кадра.
        /// </summary>
        public uint FrameNumber; //Reset when you go to next page
    }

    /// <summary>
    /// Used with TwMSG.EndXfer to indicate additional entry.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwPendingXfers {								// TW_PENDINGXFERS
        public ushort Count;
        public uint EOJ;
    }

    /// <summary>
    /// Used by appId to get/set capability from/in a entry source.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwCapability:IDisposable {					// TW_CAPABILITY

        /// <summary>
        /// Id of capability to set or get, e.g. TwCap.Brightness
        /// </summary>
        [MarshalAs(UnmanagedType.U2)]
        public TwCap Cap;

        /// <summary>
        /// TwOn.One, TwOn.Range, TwOn.Array or TwOn.Enum
        /// </summary>
        [MarshalAs(UnmanagedType.U2)]
        public TwOn ConType;

        /// <summary>
        /// Handle to container of type Dat
        /// </summary>
        public IntPtr Handle;

        private TwCapability() {
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="TwCapability"/> class.
        /// </summary>
        /// <param name="cap">The cap.</param>
        public TwCapability(TwCap cap) {
            this.Cap=cap;
            this.ConType=TwOn.DontCare;
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="TwCapability"/> class.
        /// </summary>
        /// <param name="cap">The cap.</param>
        /// <param name="value">The value.</param>
        /// <param name="type">The type.</param>
        public TwCapability(TwCap cap, uint value, TwType type) {
            this.Cap=cap;
            this.ConType=TwOn.One;
            this._SetValue(new TwOneValue() {
                ItemType=type,
                Item=value
            });
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="TwCapability"/> class.
        /// </summary>
        /// <param name="cap">The cap.</param>
        /// <param name="value">The value.</param>
        /// <param name="type">The type.</param>
        public TwCapability(TwCap cap, string value, TwType type) {
            this.Cap=cap;
            this.ConType=TwOn.One;
            int _twOneCustumValueSize=Marshal.SizeOf(typeof(TwOneCustumValue));
            this.Handle=DataSourceServices.Memory.Alloc(_twOneCustumValueSize+Marshal.SizeOf(TwTypeHelper.TypeOf(type)));
            IntPtr _ptr=DataSourceServices.Memory.Lock(this.Handle);
            try {
                Marshal.StructureToPtr(new TwOneCustumValue {
                    ItemType=type
                }, _ptr, true);
                Marshal.StructureToPtr(TwTypeHelper.CastToTw(type, value), (IntPtr)(_ptr.ToInt64()+_twOneCustumValueSize), true);
            } finally {
                DataSourceServices.Memory.Unlock(this.Handle);
            }
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="TwCapability"/> class.
        /// </summary>
        /// <param name="cap">The cap.</param>
        /// <param name="range">The range.</param>
        public TwCapability(TwCap cap, TwRange range) {
            this.Cap=cap;
            this.ConType=TwOn.Range;
            this._SetValue(range);
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="TwCapability"/> class.
        /// </summary>
        /// <param name="cap">The cap.</param>
        /// <param name="array">The array.</param>
        /// <param name="arrayValue">The array value.</param>
        public TwCapability(TwCap cap, TwArray array, object[] arrayValue) {
            this.Cap=cap;
            this.ConType=TwOn.Array;
            int _twArraySize=Marshal.SizeOf(typeof(TwArray));
            int _twItemSize=Marshal.SizeOf(TwTypeHelper.TypeOf(array.ItemType));
            this.Handle=DataSourceServices.Memory.Alloc(_twArraySize+(_twItemSize*arrayValue.Length));
            IntPtr _pTwArray=DataSourceServices.Memory.Lock(this.Handle);
            try {
                Marshal.StructureToPtr(array, _pTwArray, true);
                for(long i=0, _ptr=_pTwArray.ToInt64()+_twArraySize; i<arrayValue.Length; i++, _ptr+=_twItemSize) {
                    Marshal.StructureToPtr(TwTypeHelper.CastToTw(array.ItemType, arrayValue[i]), (IntPtr)_ptr, true);
                }
            } finally {
                DataSourceServices.Memory.Unlock(this.Handle);
            }
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="TwCapability"/> class.
        /// </summary>
        /// <param name="cap">The cap.</param>
        /// <param name="enumeration">The enumeration.</param>
        /// <param name="enumerationValue">The enumeration value.</param>
        public TwCapability(TwCap cap, TwEnumeration enumeration, object[] enumerationValue) {
            this.Cap=cap;
            this.ConType=TwOn.Enum;
            int _twEnumerationSize=Marshal.SizeOf(typeof(TwEnumeration));
            int _twItemSize=Marshal.SizeOf(TwTypeHelper.TypeOf(enumeration.ItemType));
            this.Handle=DataSourceServices.Memory.Alloc(_twEnumerationSize+(_twItemSize*enumerationValue.Length));
            IntPtr _pTwEnumeration=DataSourceServices.Memory.Lock(this.Handle);
            try {
                Marshal.StructureToPtr(enumeration, _pTwEnumeration, true);
                for(long i=0, _ptr=_pTwEnumeration.ToInt64()+_twEnumerationSize; i<enumerationValue.Length; i++, _ptr+=_twItemSize) {
                    Marshal.StructureToPtr(TwTypeHelper.CastToTw(enumeration.ItemType, enumerationValue[i]), (IntPtr)_ptr, true);
                }
            } finally {
                DataSourceServices.Memory.Unlock(this.Handle);
            }
        }

        /// <summary>
        /// Возвращает результат для указаной возможности.
        /// </summary>
        /// <returns>Экземпляр TwArray, TwEnumeration, _TwRange или _TwOneValue.</returns>
        public object GetValue() {
            IntPtr _ptr=DataSourceServices.Memory.Lock(this.Handle);
            try {
                switch(this.ConType) {
                    case TwOn.Array:
                        return new __TwArray((TwArray)Marshal.PtrToStructure(_ptr, typeof(TwArray)), (IntPtr)(_ptr.ToInt64()+Marshal.SizeOf(typeof(TwArray))));
                    case TwOn.Enum:
                        return new __TwEnumeration((TwEnumeration)Marshal.PtrToStructure(_ptr, typeof(TwEnumeration)), (IntPtr)(_ptr.ToInt64()+Marshal.SizeOf(typeof(TwEnumeration))));
                    case TwOn.Range:
                        return Marshal.PtrToStructure(_ptr, typeof(TwRange));
                    case TwOn.One:
                        TwOneCustumValue _value=Marshal.PtrToStructure(_ptr, typeof(TwOneCustumValue)) as TwOneCustumValue;
                        switch(_value.ItemType) {
                            case TwType.Str32:
                            case TwType.Str64:
                            case TwType.Str128:
                            case TwType.Str255:
                            case TwType.Str1024:
                            case TwType.Uni512:
                                return Marshal.PtrToStructure((IntPtr)(_ptr.ToInt64()+Marshal.SizeOf(typeof(TwOneCustumValue))), TwTypeHelper.TypeOf(_value.ItemType));
                            default:
                                return Marshal.PtrToStructure(_ptr, typeof(TwOneValue));
                        }
                }
                return null;
            } finally {
                DataSourceServices.Memory.Unlock(this.Handle);
            }
        }

        #region IDisposable

        /// <summary>
        /// Performs appId-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
        /// </summary>
        public void Dispose() {
            if(this.Handle!=IntPtr.Zero) {
                DataSourceServices.Memory.Free(this.Handle);
                this.Handle=IntPtr.Zero;
            }
        }

        #endregion

        private void _SetValue<T>(T value) {
            this.Handle=DataSourceServices.Memory.Alloc(Marshal.SizeOf(typeof(T)));
            IntPtr _ptr=DataSourceServices.Memory.Lock(this.Handle);
            try {
                Marshal.StructureToPtr(value, _ptr, true);
            } finally {
                DataSourceServices.Memory.Unlock(this.Handle);
            }
        }
    }

    internal interface ITwArray {

        TwType ItemType {
            get;
            set;
        }

        uint NumItems {
            get;
            set;
        }
    }

    /// <summary>
    /// Container for array of values.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwArray:ITwArray {                                    //TWON_ARRAY. Container for array of values (a simplified TW_ENUMERATION)
        [MarshalAs(UnmanagedType.U2)]
        private TwType _itemType;
        private uint _numItems;    /* How many items in ItemList           */
        //[MarshalAs(UnmanagedType.ByValArray,SizeConst=1)]
        //public byte[] ItemList; /* Array of ItemType values starts here */

        public TwType ItemType {
            get {
                return this._itemType;
            }
            set {
                this._itemType=value;
            }
        }

        public uint NumItems {
            get {
                return this._numItems;
            }
            set {
                this._numItems=value;
            }
        }
    }

    /// <summary>
    /// Container for a collection of values.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwEnumeration:ITwArray {                              //TWON_ENUMERATION. Container for a collection of values.
        [MarshalAs(UnmanagedType.U2)]
        private TwType _ItemType;
        private uint _numItems;     /* How many items in ItemList                 */
        private uint _currentIndex; /* Current value is in ItemList[CurrentIndex] */
        private uint _defaultIndex; /* Powerup value is in ItemList[DefaultIndex] */
        //[MarshalAs(UnmanagedType.ByValArray,SizeConst=1)]
        //public byte[] ItemList;  /* Array of ItemType values starts here       */

        public TwType ItemType {
            get {
                return this._ItemType;
            }
            set {
                this._ItemType=value;
            }
        }

        public uint NumItems {
            get {
                return this._numItems;
            }
            set {
                this._numItems=value;
            }
        }

        public uint CurrentIndex {
            get {
                return this._currentIndex;
            }
            set {
                this._currentIndex=value;
            }
        }

        public uint DefaultIndex {
            get {
                return this._defaultIndex;
            }
            set {
                this._defaultIndex=value;
            }
        }
    }

    /// <summary>
    /// Container for one value.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwOneValue {                                 //TW_ONEVALUE. Container for one value.
        [MarshalAs(UnmanagedType.U2)]
        public TwType ItemType;
        public uint Item;
    }

    /// <summary>
    /// Container for one custom value.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwOneCustumValue {                                 //TW_ONEVALUE. Container for one value.
        [MarshalAs(UnmanagedType.U2)]
        public TwType ItemType;
    }

    /// <summary>
    /// Container for a range of values.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwRange {                                    //TWON_RANGE. Container for a range of values.
        [MarshalAs(UnmanagedType.U2)]
        public TwType ItemType;
        public uint MinValue;     /* Starting value in the range.           */
        public uint MaxValue;     /* Final value in the range.              */
        public uint StepSize;     /* Increment from MinValue to MaxValue.   */
        public uint DefaultValue; /* Power-up value.                        */
        public uint CurrentValue; /* The value that is currently in effect. */
    }

    /// <summary>
    /// Sets up DS to appId entry transfer via a memory buffer.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwSetupMemXfer {

        /// <summary>
        /// Minimum buffer size in bytes
        /// </summary>
        public uint MinBufSize;

        /// <summary>
        /// Maximum buffer size in bytes
        /// </summary>
        public uint MaxBufSize;

        /// <summary>
        /// Preferred buffer size in bytes
        /// </summary>
        public uint Preferred;
    }

    /// <summary>
    /// Used to pass image entry (e.g. in strips) from DS to appId.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwImageMemXfer {

        public TwImageMemXfer() {
            this.Compression=(TwCompression)ushort.MaxValue;
            this.BytesPerRow=this.BytesWritten=this.Columns=this.Rows=this.XOffset=this.YOffset=uint.MaxValue;
        }

        /// <summary>
        /// How the entry is compressed.
        /// </summary>
        [MarshalAs(UnmanagedType.U2)]
        public TwCompression Compression;

        /// <summary>
        /// Number of bytes in a row of entry.
        /// </summary>
        public uint BytesPerRow;

        /// <summary>
        /// How many columns.
        /// </summary>
        public uint Columns;

        /// <summary>
        /// How many rows.
        /// </summary>
        public uint Rows;

        /// <summary>
        /// How far from the side of the image.
        /// </summary>
        public uint XOffset;

        /// <summary>
        /// How far from the top of the image.
        /// </summary>
        public uint YOffset;

        /// <summary>
        /// How many bytes written in Memory.
        /// </summary>
        public uint BytesWritten;

        /// <summary>
        /// Mem struct used to pass actual image entry.
        /// </summary>
        public TwMemory Memory;
    }

    /// <summary>
    /// Used to manage memory buffers.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwMemory {

        /// <summary>
        /// Any combination of the TWMF_ constants.
        /// </summary>
        [MarshalAs(UnmanagedType.U4)]
        public TwMF Flags;

        /// <summary>
        /// Number of bytes stored in buffer TheMem.
        /// </summary>
        public uint Length;

        /// <summary>
        /// Pointer or handle to the allocated memory buffer.
        /// </summary>
        public IntPtr TheMem;
    }

    /// <summary>
    /// Sets up DS to appId entry transfer via a file.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwSetupFileXfer {

        /// <summary>
        /// File to contain entry.
        /// </summary>
        public TwStr255 FileName;

        /// <summary>
        /// A TWFF_xxxx constant.
        /// </summary>
        [MarshalAs(UnmanagedType.U2)]
        public TwFF Format;

        /// <summary>
        /// Used for Macintosh only.
        /// </summary>
        public IntPtr VrefNum;
    }

    /// <summary>
    /// DAT_PALETTE8. Color palette when TWPT_PALETTE pixels xfer'd in mem buf.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwPalette8 {

        /// <summary>
        /// Number of colors in the color table.
        /// </summary>
        public ushort NumColors;

        /// <summary>
        /// TWPA_xxxx, specifies type of palette.
        /// </summary>
        [MarshalAs(UnmanagedType.U2)]
        public TwPA PaletteType;

        /// <summary>
        /// Array of palette values starts here.
        /// </summary>
        [MarshalAs(UnmanagedType.ByValArray, SizeConst=256)]
        public TwElement8[] Colors;

        //public static implicit operator Twain32.ColorPalette(TwPalette8 palette) {
        //    return Twain32.ColorPalette.Create(palette);
        //}

        //public static implicit operator TwPalette8(Twain32.ColorPalette palette) {
        //    TwPalette8 _result=new TwPalette8 {
        //        PaletteType=palette.PaletteType,
        //        NumColors=(ushort)palette.Colors.Length,
        //        Colors=new TwElement8[256]
        //    };
        //    for(int i=0; i<palette.Colors.Length; i++) {
        //        _result.Colors[i]=palette.Colors[i];
        //    }
        //    return _result;
        //}
    }

    /// <summary>
    /// No DAT needed.
    /// </summary>
    [DebuggerDisplay("RGB=({Channel1},{Channel2},{Channel3}), Index={Index}")]
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal struct TwElement8 {

        /// <summary>
        /// Value used to index into the color table.
        /// </summary>
        public byte Index;

        /// <summary>
        /// First  tri-stimulus value (e.g Red).
        /// </summary>
        public byte Channel1;

        /// <summary>
        /// Second tri-stimulus value (e.g Green).
        /// </summary>
        public byte Channel2;

        /// <summary>
        /// Third  tri-stimulus value (e.g Blue).
        /// </summary>
        public byte Channel3;

        public static implicit operator Color(TwElement8 element) {
            return Color.FromArgb(element.Channel1, element.Channel2, element.Channel3);
        }

        public static implicit operator TwElement8(Color color) {
            return new TwElement8 {
                Channel1=color.R,
                Channel2=color.G,
                Channel3=color.B
            };
        }
    }

    /// <summary>
    /// DAT_DEVICEEVENT, information about events.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwDeviceEvent {

        /// <summary>
        /// One of the TWDE_xxxx values.
        /// </summary>
        [MarshalAs(UnmanagedType.U2)]
        public TwDE Event;

        private ushort reserved;

        /// <summary>
        /// The name of the device that generated the event.
        /// </summary>
        public TwStr255 DeviceName;

        /// <summary>
        /// Battery Minutes Remaining.
        /// </summary>
        public uint BatteryMinutes;

        /// <summary>
        /// Battery Percentage Remaining.
        /// </summary>
        public short BatteryPercentAge;

        /// <summary>
        /// Power Supply.
        /// </summary>
        public int PowerSupply;

        /// <summary>
        /// Resolution.
        /// </summary>
        public TwFix32 XResolution;

        /// <summary>
        /// Resolution.
        /// </summary>
        public TwFix32 YResolution;

        /// <summary>
        /// Flash Used2.
        /// </summary>
        public uint FlashUsed2;

        /// <summary>
        /// Automatic Capture.
        /// </summary>
        public uint AutomaticCapture;

        /// <summary>
        /// Automatic Capture.
        /// </summary>
        public uint TimeBeforeFirstCapture;

        /// <summary>
        /// Automatic Capture.
        /// </summary>
        public uint TimeBetweenCaptures;
    }

    /// <summary>
    /// Used to register callbacks.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwCallback {

        [MarshalAs(UnmanagedType.FunctionPtr)]
        public CallBackProc CallBackProc;

        public uint RefCon;

        public short Message;
    }

    /// <summary>
    /// Used to register callbacks.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwCallback2 {

        [MarshalAs(UnmanagedType.FunctionPtr)]
        public CallBackProc CallBackProc;

        public UIntPtr RefCon;

        public short Message;
    }

    [return: MarshalAs(UnmanagedType.U2)]
    internal delegate TwRC CallBackProc(TwIdentity appId, TwIdentity srcId, [MarshalAs(UnmanagedType.U4)]TwDG dg, [MarshalAs(UnmanagedType.U2)]TwDAT dat, [MarshalAs(UnmanagedType.U2)]TwMSG msg, IntPtr data);

    #endregion

    #region Internal Type Definitions

    internal interface __ITwArray {

        TwType ItemType {
            get;
        }

        uint NumItems {
            get;
        }

        object[] Items {
            get;
        }
    }

    internal interface __ITwEnumeration:__ITwArray {

        int CurrentIndex {
            get;
        }

        int DefaultIndex {
            get;
        }
    }

    /// <summary>
    /// Container for array of values.
    /// </summary>
    /// <typeparam name="T"></typeparam>
    internal class __TwArray:__ITwArray {
        private ITwArray _data;
        private object[] _items;

        internal __TwArray(ITwArray data, IntPtr items) {
            this._data=data;
            this._items=new object[this._data.NumItems];
            for(long i=0, _offset=0, _sizeof=TwTypeHelper.SizeOf(this._data.ItemType); i<this._data.NumItems; i++, _offset+=_sizeof) {
                this._items[i]=TwTypeHelper.CastToCommon(this._data.ItemType, Marshal.PtrToStructure((IntPtr)(items.ToInt64()+_offset), TwTypeHelper.TypeOf(this._data.ItemType)));
            }
        }

        public TwType ItemType {
            get {
                return this._data.ItemType;
            }
        }

        public uint NumItems {
            get {
                return this._data.NumItems;
            }
        }

        public object[] Items {
            get {
                return this._items;
            }
        }
    }

    /// <summary>
    /// Container for a collection of values.
    /// </summary>
    /// <typeparam name="T"></typeparam>
    internal class __TwEnumeration:__TwArray, __ITwEnumeration {
        private TwEnumeration _data;

        internal __TwEnumeration(TwEnumeration data, IntPtr items) : base(data, items) {
            this._data=data;
        }

        public int CurrentIndex {
            get {
                return (int)this._data.CurrentIndex;
            }
        }

        public int DefaultIndex {
            get {
                return (int)this._data.DefaultIndex;
            }
        }
    }

    #endregion

    #region Entry Points

    /// <summary>
    /// DAT_ENTRYPOINT. returns essential entry points.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack=2)]
    internal class TwEntryPoint {

        public TwEntryPoint() {
            this.Size=Marshal.SizeOf(this);
        }

        /// <summary>
        /// Size of the structure in bytes. 
        /// The appId must set this before calling MSG_GET. 
        /// The Source should examine this when processing a MSG_SET.
        /// </summary>
        public int Size;

        /// <summary>
        /// A pointer to the DSM_Entry function. 
        /// TWAIN 2.0 Sources must use this value instead of getting it themselves.
        /// </summary>
        public IntPtr DSM_Entry;

        /// <summary>
        /// A pointer to the memory allocation function, taking the form TW_HANDLE PASCAL DSM_MemAllocate (TW_UINT32).
        /// </summary>
        [MarshalAs(UnmanagedType.FunctionPtr)]
        public DSM_MemoryAllocate MemoryAllocate;

        /// <summary>
        /// A pointer to the memory free function, taking the form void PASCAL DSM_MemAllocate (TW_HANDLE).
        /// </summary>
        [MarshalAs(UnmanagedType.FunctionPtr)]
        public DSM_MemoryFree MemoryFree;

        /// <summary>
        /// A pointer to the memory lock function, taking the form TW_MEMREF PASCAL DSM_MemAllocate (TW_HANDLE).
        /// </summary>
        [MarshalAs(UnmanagedType.FunctionPtr)]
        public DSM_MemoryLock MemoryLock;

        /// <summary>
        /// A pointer to the memory unlock function, taking the form void PASCAL DSM_MemUnlock (TW_HANDLE).
        /// </summary>
        [MarshalAs(UnmanagedType.FunctionPtr)]
        public DSM_MemoryUnlock MemoryUnlock;
    }

    internal delegate IntPtr DSM_MemoryAllocate(int size);

    internal delegate void DSM_MemoryFree(IntPtr handle);

    internal delegate IntPtr DSM_MemoryLock(IntPtr handle);

    internal delegate void DSM_MemoryUnlock(IntPtr handle);

    //[return: MarshalAs(UnmanagedType.U2)]
    //public delegate TwRC DSEntry(TwIdentity appId, [MarshalAs(UnmanagedType.U4)]TwDG dg, [MarshalAs(UnmanagedType.U2)]TwDAT dat, [MarshalAs(UnmanagedType.U2)]TwMSG msg, IntPtr entry);

    #endregion
}