Updated readme and added some more ctors.

LICENSE.txt

@@ -1,8 +1,32 @@
 The MIT License (MIT)
 
-Copyright (c) 2012 - 2021 Eugene Wang
+Copyright (c) 2012 - 2023 Eugene Wang
-
+
-Copyright(C) 2013 - 2020 Kodak Alaris Inc.
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+
+
+
+
+# for twaincs
+
+
+Copyright(C) 2013 - 2021 Kodak Alaris Inc.
 
 Permission is hereby granted, free of charge, to any person obtaining a
 copy of this software and associated documentation files (the "Software"),

README.md

@@ -1,19 +1,18 @@
 # TWAIN dotnet library
 
-NOTE: This is a rewrite test that's based off twaincs from
+NOTE: This is a rewrite test that internally uses 
-the TWAIN Working Group and doesn't fully work yet.
+[twaincs](https://github.com/twain/twain-cs) from
-Use V3 branch for current version.
+the TWAIN Working Group. It doesn't fully work yet.
+Use V3 branch for the current version.
 
 ## Info
 
 This is a dotnet library created to make working with 
-[TWAIN](http://twain.org/) easier. 
+[TWAIN](http://twain.org/) devices easier in dotnet. 
 V4 of this lib has these goals:
 
-* Targets latest TWAIN version (2.4 as of this writing).
+* Targets latest TWAIN version (2.5).
-* Supports all the TWAIN functions in the spec (directly or through dotnet wrapper).
+* Supports full framework and netcore apps (if the framework is still supported).
-* Works with both 32 or 64 bit data sources as appropriate for the 32 or 64 bit apps.
-* Supports full framework (4.5+) and netcore apps.
 
 ## Using the lib
 

src/NTwain/Extensions/TWAINH_EXTRAS.cs

@@ -0,0 +1,459 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Globalization;
+using static TWAINWorkingGroup.TWAIN;
+
+namespace TWAINWorkingGroup
+{
+  // this contains my additions under the TWAINWorkingGroup namespace
+  // that makes some twain types easier to work with.
+
+  /// <summary>
+  /// TWAIN's boolean values.
+  /// </summary>
+  public enum BoolType : ushort
+  {
+    /// <summary>
+    /// The false value (0).
+    /// </summary>
+    False = 0,
+    /// <summary>
+    /// The true value (1).
+    /// </summary>
+    True = 1
+  }
+
+  /// <summary>
+  /// A more dotnet-friendly representation of <see cref="TW_METRICS"/>.
+  /// </summary>
+  public struct Metrics
+  {
+    /// <summary>
+    /// Return code of querying the metrics.
+    /// </summary>
+    public STS ReturnCode;
+
+    /// <summary>
+    /// The number of sheets of paper processed by the scanner.
+    /// </summary>
+    public int Sheets;
+
+    /// <summary>
+    /// The number of images made available for transfer by the driver. This is not
+    /// necessarily the same as the number of images actually transferred, since the
+    /// application may opt to skip transfers or to end without transferring all images.
+    /// </summary>
+    public int Images;
+  }
+
+  public struct TwainDirectTaskResult
+  {
+    /// <summary>
+    /// Return code of task.
+    /// </summary>
+    public STS ReturnCode;
+
+    /// <summary>
+    /// The response of the task in JSON if successful.
+    /// </summary>
+    public string ResponseJson;
+  }
+
+  /// <summary>
+  /// A more dotnet-friendly representation of <see cref="TW_ENUMERATION"/>.
+  /// </summary>
+  /// <typeparam name="TValue"></typeparam>
+  public class Enumeration<TValue> where TValue : struct
+  {
+    public int CurrentIndex;
+
+    public int DefaultIndex;
+
+    public TValue[] Items;
+  }
+
+  /// <summary>
+  /// A more dotnet-friendly representation of <see cref="TW_RANGE"/>.
+  /// </summary>
+  /// <typeparam name="TValue"></typeparam>
+  public partial class Range<TValue> : IEnumerable<TValue> where TValue : struct
+  {
+    public TValue MinValue;
+    public TValue MaxValue;
+    public TValue StepSize;
+    public TValue DefaultValue;
+    public TValue CurrentValue;
+
+    IEnumerator<TValue> IEnumerable<TValue>.GetEnumerator()
+    {
+      if (!(MinValue is IConvertible))
+        throw new NotSupportedException($"The value type {typeof(TValue).Name} is not supported for range enumeration.");
+
+      return new DynamicEnumerator(MinValue, MaxValue, StepSize);
+    }
+
+    IEnumerator IEnumerable.GetEnumerator()
+    {
+      return ((IEnumerable<TValue>)this).GetEnumerator();
+    }
+
+    // dynamic is a cheap hack to sidestep the compiler restrictions if I know TValue is numeric
+    class DynamicEnumerator : IEnumerator<TValue>
+    {
+      private readonly TValue _min;
+      private readonly TValue _max;
+      private readonly TValue _step;
+      private TValue _cur;
+      bool started = false;
+
+      public DynamicEnumerator(TValue min, TValue max, TValue step)
+      {
+        _min = min;
+        _max = max;
+        _step = step;
+        _cur = min;
+      }
+
+      public TValue Current => _cur;
+
+      object IEnumerator.Current => this.Current;
+
+      public void Dispose() { }
+
+      public bool MoveNext()
+      {
+        if (!started)
+        {
+          started = true;
+          return true;
+        }
+
+        var next = _cur + (dynamic)_step;
+        if (next == _cur || next < _min || next > _max) return false;
+
+        _cur = next;
+        return true;
+      }
+
+      public void Reset()
+      {
+        _cur = _min;
+        started = false;
+      }
+    }
+  }
+
+  partial class TWAIN
+  {
+    partial struct TW_FIX32 : IEquatable<TW_FIX32>, IConvertible
+    {
+      // the conversion logic is found in the spec.
+
+      float ToFloat()
+      {
+        return Whole + Frac / 65536f;
+      }
+      double ToDouble()
+      {
+        return Whole + Frac / 65536.0;
+      }
+      public TW_FIX32(double value)
+      {
+        Whole = (short)value;
+        Frac = (ushort)((value - Whole) * 65536.0);
+      }
+      public TW_FIX32(float value)
+      {
+        //int temp = (int)(value * 65536.0 + 0.5);
+        //Whole = (short)(temp >> 16);
+        //Fraction = (ushort)(temp & 0x0000ffff);
+
+        // different version from twain faq
+        bool sign = value < 0;
+        int temp = (int)(value * 65536.0 + (sign ? (-0.5) : 0.5));
+        Whole = (short)(temp >> 16);
+        Frac = (ushort)(temp & 0x0000ffff);
+      }
+
+      public override string ToString()
+      {
+        return ToFloat().ToString();
+      }
+
+      public bool Equals(TW_FIX32 other)
+      {
+        return Whole == other.Whole && Frac == other.Frac;
+      }
+      public override bool Equals(object obj)
+      {
+        if (obj is TW_FIX32 other)
+        {
+          return Equals(other);
+        }
+        return false;
+      }
+      public override int GetHashCode()
+      {
+        return Whole ^ Frac;
+      }
+
+
+      #region IConvertable
+
+      TypeCode IConvertible.GetTypeCode()
+      {
+        return TypeCode.Single;
+      }
+
+      bool IConvertible.ToBoolean(IFormatProvider provider)
+      {
+        return this != 0;
+      }
+
+      byte IConvertible.ToByte(IFormatProvider provider)
+      {
+        return Convert.ToByte((float)this);
+      }
+
+      char IConvertible.ToChar(IFormatProvider provider)
+      {
+        return Convert.ToChar((float)this);
+      }
+
+      DateTime IConvertible.ToDateTime(IFormatProvider provider)
+      {
+        return Convert.ToDateTime((float)this);
+      }
+
+      decimal IConvertible.ToDecimal(IFormatProvider provider)
+      {
+        return Convert.ToDecimal((float)this);
+      }
+
+      double IConvertible.ToDouble(IFormatProvider provider)
+      {
+        return Convert.ToDouble((float)this);
+      }
+
+      short IConvertible.ToInt16(IFormatProvider provider)
+      {
+        return Convert.ToInt16((float)this);
+      }
+
+      int IConvertible.ToInt32(IFormatProvider provider)
+      {
+        return Convert.ToInt32((float)this);
+      }
+
+      long IConvertible.ToInt64(IFormatProvider provider)
+      {
+        return Convert.ToInt64((float)this);
+      }
+
+      sbyte IConvertible.ToSByte(IFormatProvider provider)
+      {
+        return Convert.ToSByte((float)this);
+      }
+
+      float IConvertible.ToSingle(IFormatProvider provider)
+      {
+        return Convert.ToSingle((float)this);
+      }
+
+      string IConvertible.ToString(IFormatProvider provider)
+      {
+        return this.ToString();
+      }
+
+      object IConvertible.ToType(Type conversionType, IFormatProvider provider)
+      {
+        return Convert.ChangeType((float)this, conversionType, CultureInfo.InvariantCulture);
+      }
+
+      ushort IConvertible.ToUInt16(IFormatProvider provider)
+      {
+        return Convert.ToUInt16((float)this);
+      }
+
+      uint IConvertible.ToUInt32(IFormatProvider provider)
+      {
+        return Convert.ToUInt32((float)this);
+      }
+
+      ulong IConvertible.ToUInt64(IFormatProvider provider)
+      {
+        return Convert.ToUInt64((float)this);
+      }
+
+      #endregion
+
+      public static implicit operator float(TW_FIX32 value) => value.ToFloat();
+      public static implicit operator TW_FIX32(float value) => new TW_FIX32(value);
+
+      public static implicit operator double(TW_FIX32 value) => value.ToDouble();
+      public static implicit operator TW_FIX32(double value) => new TW_FIX32((float)value);
+
+      public static bool operator ==(TW_FIX32 value1, TW_FIX32 value2) => value1.Equals(value2);
+      public static bool operator !=(TW_FIX32 value1, TW_FIX32 value2) => !value1.Equals(value2);
+    }
+
+    partial struct TW_FRAME : IEquatable<TW_FRAME>
+    {
+      /// <summary>
+      /// Creates <see cref="TW_FRAME"/> from a string representation of it.
+      /// </summary>
+      /// <param name="value"></param>
+      public TW_FRAME(string value) : this()
+      {
+        var parts = value.Split(',');
+        if (parts.Length == 4)
+        {
+          Left = float.Parse(parts[0]);
+          Top = float.Parse(parts[1]);
+          Right = float.Parse(parts[2]);
+          Bottom = float.Parse(parts[3]);
+        }
+        else
+        {
+          throw new ArgumentException($"Cannot create frame from \"{value}\".");
+        }
+      }
+
+      /// <summary>
+      /// String representation of Left,Top,Right,Bottom.
+      /// </summary>
+      /// <returns></returns>
+      public override string ToString()
+      {
+        return $"{Left},{Top},{Right},{Bottom}";
+      }
+
+      public bool Equals(TW_FRAME other)
+      {
+        return Left == other.Left && Top == other.Top &&
+            Right == other.Right && Bottom == other.Bottom;
+      }
+
+      public override bool Equals(object obj)
+      {
+        if (obj is TW_FRAME other)
+        {
+          return Equals(other);
+        }
+        return false;
+      }
+
+      public override int GetHashCode()
+      {
+        return Left.GetHashCode() ^ Top.GetHashCode() ^
+            Right.GetHashCode() ^ Bottom.GetHashCode();
+      }
+
+
+      public static bool operator ==(TW_FRAME value1, TW_FRAME value2)
+      {
+        return value1.Equals(value2);
+      }
+      public static bool operator !=(TW_FRAME value1, TW_FRAME value2)
+      {
+        return !value1.Equals(value2);
+      }
+    }
+
+    partial struct TW_STR32
+    {
+      public const int Size = 34;
+
+      public TW_STR32(string value) : this()
+      {
+        Set(value);
+      }
+
+      public override string ToString()
+      {
+        return Get();
+      }
+
+      public static implicit operator string(TW_STR32 value) => value.ToString();
+      public static explicit operator TW_STR32(string value) => new TW_STR32(value);
+
+    }
+
+    partial struct TW_STR64
+    {
+      public const int Size = 66;
+
+      public TW_STR64(string value) : this()
+      {
+        Set(value);
+      }
+
+      public override string ToString()
+      {
+        return Get();
+      }
+
+      public static implicit operator string(TW_STR64 value) => value.ToString();
+      public static explicit operator TW_STR64(string value) => new TW_STR64(value);
+    }
+
+    partial struct TW_STR128
+    {
+      public const int Size = 130;
+
+      public TW_STR128(string value) : this()
+      {
+        Set(value);
+      }
+
+      public override string ToString()
+      {
+        return Get();
+      }
+
+      public static implicit operator string(TW_STR128 value) => value.ToString();
+      public static explicit operator TW_STR128(string value) => new TW_STR128(value);
+    }
+
+    partial struct TW_STR255
+    {
+      public const int Size = 256;
+
+      public TW_STR255(string value) : this()
+      {
+        Set(value);
+      }
+
+      public override string ToString()
+      {
+        return Get();
+      }
+
+      public static implicit operator string(TW_STR255 value) => value.ToString();
+      public static explicit operator TW_STR255(string value) => new TW_STR255(value);
+    }
+
+    partial struct TW_IDENTITY
+    {
+      public override string ToString()
+      {
+        return $"{Manufacturer} - {ProductName} {Version} (TWAIN {ProtocolMajor}.{ProtocolMinor})";
+      }
+    }
+
+    partial struct TW_VERSION
+    {
+      public override string ToString()
+      {
+        return $"{MajorNum}.{MinorNum}";
+      }
+    }
+
+    //partial struct TW_DEVICEEVENT
+    //{
+    //    public TWDE Event { get { return (TWDE)_event; } }
+    //    public TWFL FlashUsed2 { get { return (TWFL)_flashUsed2; } }
+    //}
+  }
+}

src/NTwain/NTwain.csproj

@@ -3,9 +3,9 @@
 	<PropertyGroup>
 		<PackageId>NTwain</PackageId>
 		<Description>Library containing the TWAIN API for dotnet.</Description>
-		<TargetFrameworks>net462;netcoreapp3.1;net5.0;net6.0</TargetFrameworks>
+		<TargetFrameworks>net462;netcoreapp3.1;net5.0;net6.0;net7.0;netstandard2.0</TargetFrameworks>
 		<AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-		<LangVersion>10.0</LangVersion>
+		<LangVersion>11</LangVersion>
 	</PropertyGroup>
 
 	<ItemGroup>

src/NTwain/TWAINH_EXTRAS.cs

@@ -1,462 +0,0 @@
-using NTwain;
-using System;
-using System.Collections;
-using System.Collections.Generic;
-using System.Globalization;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-using static TWAINWorkingGroup.TWAIN;
-
-namespace TWAINWorkingGroup
-{
-    // contains my additions that makes twain types easier to work with.
-
-    /// <summary>
-    /// TWAIN's boolean values.
-    /// </summary>
-    public enum BoolType : ushort
-    {
-        /// <summary>
-        /// The false value (0).
-        /// </summary>
-        False = 0,
-        /// <summary>
-        /// The true value (1).
-        /// </summary>
-        True = 1
-    }
-
-    /// <summary>
-    /// A more dotnet-friendly representation of <see cref="TW_METRICS"/>.
-    /// </summary>
-    public struct Metrics
-    {
-        /// <summary>
-        /// Return code of querying the metrics.
-        /// </summary>
-        public STS ReturnCode;
-
-        /// <summary>
-        /// The number of sheets of paper processed by the scanner.
-        /// </summary>
-        public int Sheets;
-
-        /// <summary>
-        /// The number of images made available for transfer by the driver. This is not
-        /// necessarily the same as the number of images actually transferred, since the
-        /// application may opt to skip transfers or to end without transferring all images.
-        /// </summary>
-        public int Images;
-    }
-
-    public struct TwainDirectTaskResult
-    {
-        /// <summary>
-        /// Return code of task.
-        /// </summary>
-        public STS ReturnCode;
-
-        /// <summary>
-        /// The response of the task in JSON if successful.
-        /// </summary>
-        public string ResponseJson;
-    }
-
-    /// <summary>
-    /// A more dotnet-friendly representation of <see cref="TW_ENUMERATION"/>.
-    /// </summary>
-    /// <typeparam name="TValue"></typeparam>
-    public class Enumeration<TValue> where TValue : struct
-    {
-        public int CurrentIndex;
-
-        public int DefaultIndex;
-
-        public TValue[] Items;
-    }
-
-    /// <summary>
-    /// A more dotnet-friendly representation of <see cref="TW_RANGE"/>.
-    /// </summary>
-    /// <typeparam name="TValue"></typeparam>
-    public partial class Range<TValue> : IEnumerable<TValue> where TValue : struct
-    {
-        public TValue MinValue;
-        public TValue MaxValue;
-        public TValue StepSize;
-        public TValue DefaultValue;
-        public TValue CurrentValue;
-
-        IEnumerator<TValue> IEnumerable<TValue>.GetEnumerator()
-        {
-            if (!(MinValue is IConvertible))
-                throw new NotSupportedException($"The value type {typeof(TValue).Name} is not supported for range enumeration.");
-
-            return new DynamicEnumerator(MinValue, MaxValue, StepSize);
-        }
-
-        IEnumerator IEnumerable.GetEnumerator()
-        {
-            return ((IEnumerable<TValue>)this).GetEnumerator();
-        }
-
-        // dynamic is a cheap hack to sidestep the compiler restrictions if I know TValue is numeric
-        class DynamicEnumerator : IEnumerator<TValue>
-        {
-            private readonly TValue _min;
-            private readonly TValue _max;
-            private readonly TValue _step;
-            private TValue _cur;
-            bool started = false;
-
-            public DynamicEnumerator(TValue min, TValue max, TValue step)
-            {
-                _min = min;
-                _max = max;
-                _step = step;
-                _cur = min;
-            }
-
-            public TValue Current => _cur;
-
-            object IEnumerator.Current => this.Current;
-
-            public void Dispose() { }
-
-            public bool MoveNext()
-            {
-                if (!started)
-                {
-                    started = true;
-                    return true;
-                }
-
-                var next = _cur + (dynamic)_step;
-                if (next == _cur || next < _min || next > _max) return false;
-
-                _cur = next;
-                return true;
-            }
-
-            public void Reset()
-            {
-                _cur = _min;
-                started = false;
-            }
-        }
-    }
-
-    partial class TWAIN
-    {
-        partial struct TW_FIX32 : IEquatable<TW_FIX32>, IConvertible
-        {
-            // the conversion logic is found in the spec.
-
-            float ToFloat()
-            {
-                return Whole + Frac / 65536f;
-            }
-            double ToDouble()
-            {
-                return Whole + Frac / 65536.0;
-            }
-            public TW_FIX32(double value)
-            {
-                Whole = (short)value;
-                Frac = (ushort)((value - Whole) * 65536.0);
-            }
-            public TW_FIX32(float value)
-            {
-                //int temp = (int)(value * 65536.0 + 0.5);
-                //Whole = (short)(temp >> 16);
-                //Fraction = (ushort)(temp & 0x0000ffff);
-
-                // different version from twain faq
-                bool sign = value < 0;
-                int temp = (int)(value * 65536.0 + (sign ? (-0.5) : 0.5));
-                Whole = (short)(temp >> 16);
-                Frac = (ushort)(temp & 0x0000ffff);
-            }
-
-            public override string ToString()
-            {
-                return ToFloat().ToString();
-            }
-
-            public bool Equals(TW_FIX32 other)
-            {
-                return Whole == other.Whole && Frac == other.Frac;
-            }
-            public override bool Equals(object obj)
-            {
-                if (obj is TW_FIX32 other)
-                {
-                    return Equals(other);
-                }
-                return false;
-            }
-            public override int GetHashCode()
-            {
-                return Whole ^ Frac;
-            }
-
-
-            #region IConvertable
-
-            TypeCode IConvertible.GetTypeCode()
-            {
-                return TypeCode.Single;
-            }
-
-            bool IConvertible.ToBoolean(IFormatProvider provider)
-            {
-                return this != 0;
-            }
-
-            byte IConvertible.ToByte(IFormatProvider provider)
-            {
-                return Convert.ToByte((float)this);
-            }
-
-            char IConvertible.ToChar(IFormatProvider provider)
-            {
-                return Convert.ToChar((float)this);
-            }
-
-            DateTime IConvertible.ToDateTime(IFormatProvider provider)
-            {
-                return Convert.ToDateTime((float)this);
-            }
-
-            decimal IConvertible.ToDecimal(IFormatProvider provider)
-            {
-                return Convert.ToDecimal((float)this);
-            }
-
-            double IConvertible.ToDouble(IFormatProvider provider)
-            {
-                return Convert.ToDouble((float)this);
-            }
-
-            short IConvertible.ToInt16(IFormatProvider provider)
-            {
-                return Convert.ToInt16((float)this);
-            }
-
-            int IConvertible.ToInt32(IFormatProvider provider)
-            {
-                return Convert.ToInt32((float)this);
-            }
-
-            long IConvertible.ToInt64(IFormatProvider provider)
-            {
-                return Convert.ToInt64((float)this);
-            }
-
-            sbyte IConvertible.ToSByte(IFormatProvider provider)
-            {
-                return Convert.ToSByte((float)this);
-            }
-
-            float IConvertible.ToSingle(IFormatProvider provider)
-            {
-                return Convert.ToSingle((float)this);
-            }
-
-            string IConvertible.ToString(IFormatProvider provider)
-            {
-                return this.ToString();
-            }
-
-            object IConvertible.ToType(Type conversionType, IFormatProvider provider)
-            {
-                return Convert.ChangeType((float)this, conversionType, CultureInfo.InvariantCulture);
-            }
-
-            ushort IConvertible.ToUInt16(IFormatProvider provider)
-            {
-                return Convert.ToUInt16((float)this);
-            }
-
-            uint IConvertible.ToUInt32(IFormatProvider provider)
-            {
-                return Convert.ToUInt32((float)this);
-            }
-
-            ulong IConvertible.ToUInt64(IFormatProvider provider)
-            {
-                return Convert.ToUInt64((float)this);
-            }
-
-            #endregion
-
-            public static implicit operator float(TW_FIX32 value) => value.ToFloat();
-            public static implicit operator TW_FIX32(float value) => new TW_FIX32(value);
-
-            public static implicit operator double(TW_FIX32 value) => value.ToDouble();
-            public static implicit operator TW_FIX32(double value) => new TW_FIX32((float)value);
-
-            public static bool operator ==(TW_FIX32 value1, TW_FIX32 value2) => value1.Equals(value2);
-            public static bool operator !=(TW_FIX32 value1, TW_FIX32 value2) => !value1.Equals(value2);
-        }
-
-        partial struct TW_FRAME : IEquatable<TW_FRAME>
-        {
-            /// <summary>
-            /// Creates <see cref="TW_FRAME"/> from a string representation of it.
-            /// </summary>
-            /// <param name="value"></param>
-            public TW_FRAME(string value) : this()
-            {
-                var parts = value.Split(',');
-                if (parts.Length == 4)
-                {
-                    Left = float.Parse(parts[0]);
-                    Top = float.Parse(parts[1]);
-                    Right = float.Parse(parts[2]);
-                    Bottom = float.Parse(parts[3]);
-                }
-                else
-                {
-                    throw new ArgumentException($"Cannot create frame from \"{value}\".");
-                }
-            }
-
-            /// <summary>
-            /// String representation of Left,Top,Right,Bottom.
-            /// </summary>
-            /// <returns></returns>
-            public override string ToString()
-            {
-                return $"{Left},{Top},{Right},{Bottom}";
-            }
-
-            public bool Equals(TW_FRAME other)
-            {
-                return Left == other.Left && Top == other.Top &&
-                    Right == other.Right && Bottom == other.Bottom;
-            }
-
-            public override bool Equals(object obj)
-            {
-                if (obj is TW_FRAME other)
-                {
-                    return Equals(other);
-                }
-                return false;
-            }
-
-            public override int GetHashCode()
-            {
-                return Left.GetHashCode() ^ Top.GetHashCode() ^
-                    Right.GetHashCode() ^ Bottom.GetHashCode();
-            }
-
-
-            public static bool operator ==(TW_FRAME value1, TW_FRAME value2)
-            {
-                return value1.Equals(value2);
-            }
-            public static bool operator !=(TW_FRAME value1, TW_FRAME value2)
-            {
-                return !value1.Equals(value2);
-            }
-        }
-
-        partial struct TW_STR32
-        {
-            public const int Size = 34;
-
-            public TW_STR32(string value) : this()
-            {
-                Set(value);
-            }
-
-            public override string ToString()
-            {
-                return Get();
-            }
-
-            public static implicit operator string(TW_STR32 value) => value.ToString();
-            public static explicit operator TW_STR32(string value) => new TW_STR32(value);
-
-        }
-
-        partial struct TW_STR64
-        {
-            public const int Size = 66;
-
-            public TW_STR64(string value) : this()
-            {
-                Set(value);
-            }
-
-            public override string ToString()
-            {
-                return Get();
-            }
-
-            public static implicit operator string(TW_STR64 value) => value.ToString();
-            public static explicit operator TW_STR64(string value) => new TW_STR64(value);
-        }
-
-        partial struct TW_STR128
-        {
-            public const int Size = 130;
-
-            public TW_STR128(string value) : this()
-            {
-                Set(value);
-            }
-
-            public override string ToString()
-            {
-                return Get();
-            }
-
-            public static implicit operator string(TW_STR128 value) => value.ToString();
-            public static explicit operator TW_STR128(string value) => new TW_STR128(value);
-        }
-
-        partial struct TW_STR255
-        {
-            public const int Size = 256;
-
-            public TW_STR255(string value) : this()
-            {
-                Set(value);
-            }
-
-            public override string ToString()
-            {
-                return Get();
-            }
-
-            public static implicit operator string(TW_STR255 value) => value.ToString();
-            public static explicit operator TW_STR255(string value) => new TW_STR255(value);
-        }
-
-        partial struct TW_IDENTITY
-        {
-            public override string ToString()
-            {
-                return $"{Manufacturer} - {ProductName} {Version} (TWAIN {ProtocolMajor}.{ProtocolMinor})";
-            }
-        }
-
-        partial struct TW_VERSION
-        {
-            public override string ToString()
-            {
-                return $"{MajorNum}.{MinorNum}";
-            }
-        }
-
-        //partial struct TW_DEVICEEVENT
-        //{
-        //    public TWDE Event { get { return (TWDE)_event; } }
-        //    public TWFL FlashUsed2 { get { return (TWFL)_flashUsed2; } }
-        //}
-    }
-}

src/NTwain/TwainSession.cs

@@ -1,19 +1,19 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
-using System.Globalization;
-using System.Linq;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
-using System.Text;
 using System.Threading;
-using System.Threading.Tasks;
 using TWAINWorkingGroup;
 using static TWAINWorkingGroup.TWAIN;
 
 namespace NTwain
 {
+  /// <summary>
+  /// A wrapper around the low-level <see cref="TWAIN"/> object 
+  /// that may be easier to use in dotnet with typical scenarios.
+  /// </summary>
   public class TwainSession : IDisposable
   {
     private TWAIN _twain;
@@ -21,14 +21,24 @@ namespace NTwain
     private readonly IThreadMarshaller _threadMarshaller;
     private IntPtr _hWnd;
 
-        public TwainSession(Assembly application,
+    public TwainSession(Assembly applicationInfo,
+        IThreadMarshaller threadMarshaller, IntPtr hWnd,
+        TWLG language = TWLG.ENGLISH_USA, TWCY country = TWCY.USA) :
+        this(FileVersionInfo.GetVersionInfo(applicationInfo.Location),
+          threadMarshaller, hWnd, language, country)
+    { }
+    public TwainSession(FileVersionInfo applicationInfo,
+        IThreadMarshaller threadMarshaller, IntPtr hWnd,
+        TWLG language = TWLG.ENGLISH_USA, TWCY country = TWCY.USA) :
+        this(applicationInfo.CompanyName, applicationInfo.ProductName, applicationInfo.ProductName,
+          threadMarshaller, hWnd, language, country)
+    { }
+    public TwainSession(string companyName, string productFamily, string productName,
         IThreadMarshaller threadMarshaller, IntPtr hWnd,
         TWLG language = TWLG.ENGLISH_USA, TWCY country = TWCY.USA)
     {
-            var info = FileVersionInfo.GetVersionInfo(application.Location);
-
       _twain = new TWAIN(
-                info.CompanyName, info.ProductName, info.ProductName,
+        companyName, productFamily, productName,
         (ushort)TWON_PROTOCOL.MAJOR, (ushort)TWON_PROTOCOL.MINOR,
         (uint)(DG.APP2 | DG.IMAGE),
         country, "", language, 2, 4, false, true,
@@ -67,7 +77,7 @@ namespace NTwain
 
     /// <summary>
     /// Gets the low-level twain object.
-        /// Only use if you know what you're doing.
+    /// Only use it if you know what you're doing.
     /// </summary>
     public TWAIN TWAIN { get { return _twain; } }
 
@@ -149,7 +159,7 @@ namespace NTwain
 
       if (_twain.IsMsgCloseDsReq() || _twain.IsMsgCloseDsOk())
       {
-                StepDown(STATE.S4);
+        _twain.Rollback(STATE.S4);
         return;
       }
 
@@ -210,7 +220,7 @@ namespace NTwain
         // TODO: may be wrong for now
         if (pending.Count == 0 || sts == STS.CANCEL || sts == STS.XFERDONE)
         {
-                    StepDown(STATE.S4);
+          _twain.Rollback(STATE.S4);
         }
         else
         {
@@ -316,7 +326,7 @@ namespace NTwain
     /// </summary>
     public void Close()
     {
-            StepDown(STATE.S2);
+      _twain.Rollback(STATE.S2);
     }
 
     /// <summary>
@@ -380,7 +390,7 @@ namespace NTwain
       }
       set
       {
-                StepDown(STATE.S3);
+        _twain.Rollback(STATE.S3);
         if (value.HasValue)
         {
           var twidentity = value.Value;
@@ -389,53 +399,6 @@ namespace NTwain
       }
     }
 
-        /// <summary>
-        /// Steps down the TWAIN state to the specified state.
-        /// </summary>
-        /// <param name="target"></param>
-        public void StepDown(STATE target)
-        {
-            // Make sure we have something to work with...
-            if (_twain == null) return;
-
-            // Walk the states, we don't care about the status returns.  Basically,
-            // these need to work, or we're guaranteed to hang...
-
-            // 7 --> 6
-            if ((State == STATE.S7) && (target < STATE.S7))
-            {
-                TW_PENDINGXFERS twpendingxfers = default;
-                _twain.DatPendingxfers(DG.CONTROL, MSG.ENDXFER, ref twpendingxfers);
-            }
-
-            // 6 --> 5
-            if ((State == STATE.S6) && (target < STATE.S6))
-            {
-                TW_PENDINGXFERS twpendingxfers = default;
-                _twain.DatPendingxfers(DG.CONTROL, MSG.RESET, ref twpendingxfers);
-            }
-
-            // 5 --> 4
-            if ((State == STATE.S5) && (target < STATE.S5))
-            {
-                TW_USERINTERFACE twuserinterface = default;
-                _twain.DatUserinterface(DG.CONTROL, MSG.DISABLEDS, ref twuserinterface);
-                SourceDisabled?.Invoke(this, EventArgs.Empty);
-            }
-
-            // 4 --> 3
-            if ((State == STATE.S4) && (target < STATE.S4))
-            {
-                _caps = null;
-                _twain.DatIdentity(DG.CONTROL, MSG.CLOSEDS, ref _twain.m_twidentityDs);
-            }
-
-            // 3 --> 2
-            if ((State == STATE.S3) && (target < STATE.S3))
-            {
-                _twain.DatParent(DG.CONTROL, MSG.CLOSEDSM, ref _hWnd);
-            }
-        }
 
     private Capabilities _caps;