Completed all triplet mapping.

NTwain/Triplets/DGControl/DGControl.Capability.cs

@@ -113,7 +113,8 @@ namespace NTwain.Triplets
 
 		/// <summary>
 		/// Changes the Current Value(s) and Available Values of the specified capability to those specified
-		/// by the application.
+		/// by the application. As of TWAIN 2.2 this only modifies the Current Value of the specified capability, constraints cannot be
+        /// changed with this.
 		/// Current Values are set when the container is a <see cref="TWOneValue"/> or <see cref="TWArray"/>. Available and
 		/// Current Values are set when the container is a <see cref="TWEnumeration"/> or <see cref="TWRange"/>.
 		/// </summary>
@@ -125,6 +126,18 @@ namespace NTwain.Triplets
 			return PInvoke.DsmEntry(Session.AppId, Session.SourceId, Message.Set, capability);
 		}
 
-        //TODO implement SetConstraint
+        /// <summary>
+        /// Changes the Current Value(s) and Available Value(s) of the specified capability to those specified
+        /// by the application.
+        /// </summary>
+        /// Current Values are set when the container is a <see cref="TWOneValue"/> or <see cref="TWArray"/>. Available and
+        /// Current Values are set when the container is a <see cref="TWEnumeration"/> or <see cref="TWRange"/>.
+        /// <param name="capability">The capability.</param>
+        /// <returns></returns>
+        public ReturnCode SetConstraint(TWCapability capability)
+        {
+            Session.VerifyState(4, 7, DataGroups.Control, DataArgumentType.Capability, Message.SetConstraint);
+            return PInvoke.DsmEntry(Session.AppId, Session.SourceId, Message.SetConstraint, capability);
+        }
 	}
 }

NTwain/Triplets/DGControl/DGControl.XferGroup.cs

@@ -4,39 +4,33 @@ using NTwain.Values;
 
 namespace NTwain.Triplets
 {
-    // TODO: implement this
-
 	public sealed class XferGroup : OpBase
 	{
 		internal XferGroup(ITwainSessionInternal session) : base(session) { }
+
 		/// <summary>
 		/// Returns the Data Group (the type of data) for the upcoming transfer. The Source is required to
 		/// only supply one of the DGs specified in the SupportedGroups field of origin.
 		/// </summary>
 		/// <param name="value">The value.</param>
 		/// <returns></returns>
-		public ReturnCode Get(out uint value)
+		public ReturnCode Get(ref uint value)
 		{
             Session.VerifyState(4, 6, DataGroups.Control, DataArgumentType.XferGroup, Message.Get);
-			throw new NotImplementedException();
+            return PInvoke.DsmEntry(Session.AppId, Session.SourceId, DataGroups.Control, DataArgumentType.XferGroup, Message.Get, ref value);
-
-			// TODO: I have no idea if this even works, just something that looks logical.
-			// Does memory from pointer need to be released once we got the value?
-
-			//IntPtr ptr = IntPtr.Zero;
-			//var rc = Custom.DsmEntry(Session.AppId, Session.SourceId, DataGroup.Control, DataArgumentType.XferGroup, Message.Get, ref ptr);
-			//unsafe
-			//{
-			//    uint* realPtr = (uint*)ptr.ToPointer();
-			//    value = (*realPtr);
-			//}
-			//return rc;
 		}
 
+        /// <summary>
+        /// The transfer group determines the kind of data being passed from the Source to the Application.
+        /// By default a TWAIN Source must default to DG_IMAGE. Currently the only other data group
+        /// supported is DG_AUDIO, which is a feature supported by some digital cameras.
+        /// </summary>
+        /// <param name="value">The value.</param>
+        /// <returns></returns>
         public ReturnCode Set(uint value)
 		{
 			Session.VerifyState(6, 6, DataGroups.Control, DataArgumentType.XferGroup, Message.Set);
-			throw new NotImplementedException();
+            return PInvoke.DsmEntry(Session.AppId, Session.SourceId, DataGroups.Control, DataArgumentType.XferGroup, Message.Set, ref value);
 		}
 	}
 }

NTwain/Triplets/DGImage/DGImage.Filter.cs

@@ -8,6 +8,54 @@ namespace NTwain.Triplets
 	{
         internal Filter(ITwainSessionInternal session) : base(session) { }
 
-        //TODO: implement this
+
+        /// <summary>
+        /// Causes the Source to return the filter parameters that will be used during the next image
+        /// acquisition.
+        /// </summary>
+        /// <param name="filter">The filter.</param>
+        /// <returns></returns>
+        public ReturnCode Get(out TWFilter filter)
+        {
+            Session.VerifyState(4, 6, DataGroups.Image, DataArgumentType.Filter, Message.Get);
+            filter = new TWFilter();
+            return PInvoke.DsmEntry(Session.AppId, Session.SourceId, Message.Get, filter);
+        }
+
+        /// <summary>
+        /// Causes the Source to return the power-on default values applied to the filter.
+        /// </summary>
+        /// <param name="filter">The filter.</param>
+        /// <returns></returns>
+        public ReturnCode GetDefault(out TWFilter filter)
+        {
+            Session.VerifyState(4, 6, DataGroups.Image, DataArgumentType.Filter, Message.GetDefault);
+            filter = new TWFilter();
+            return PInvoke.DsmEntry(Session.AppId, Session.SourceId, Message.GetDefault, filter);
+        }
+
+        /// <summary>
+        /// Allows the Application to configure the filter parameters that will be used during the next image
+        /// acquisition.
+        /// </summary>
+        /// <param name="filter">The filter.</param>
+        /// <returns></returns>
+        public ReturnCode Set(TWFilter filter)
+        {
+            Session.VerifyState(4, 4, DataGroups.Image, DataArgumentType.Filter, Message.Set);
+            return PInvoke.DsmEntry(Session.AppId, Session.SourceId, Message.Set, filter);
+        }
+
+        /// <summary>
+        /// Return the Source to using its power-on default values when it is applying the filter.
+        /// </summary>
+        /// <param name="filter">The filter.</param>
+        /// <returns></returns>
+        public ReturnCode Reset(out TWFilter filter)
+        {
+            Session.VerifyState(4, 4, DataGroups.Image, DataArgumentType.Filter, Message.Reset);
+            filter = new TWFilter();
+            return PInvoke.DsmEntry(Session.AppId, Session.SourceId, Message.Reset, filter);
+        }
 	}
 }

NTwain/Triplets/DGImage/DGImage.cs

@@ -34,6 +34,17 @@ namespace NTwain.Triplets
 			}
         }
 
+
+        Filter _filter;
+        public Filter Filter
+        {
+            get
+            {
+                if (_filter == null) { _filter = new Filter(_session); }
+                return _filter;
+            }
+        }
+
 		GrayResponse _grayResponse;
 		public GrayResponse GrayResponse
 		{

NTwain/Triplets/PInvoke.cs

@@ -39,6 +39,18 @@ namespace NTwain.Triplets
             else { return NativeMethods.DsmEntry32(origin, destination, dg, dat, msg, ref data); }
         }
 
+        public static ReturnCode DsmEntry(
+            TWIdentity origin,
+            TWIdentity destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref uint data)
+        {
+            if (Is64Bit) { return NativeMethods.DsmEntry64(origin, destination, dg, dat, msg, ref data); }
+            else { return NativeMethods.DsmEntry32(origin, destination, dg, dat, msg, ref data); }
+        }
+
 		public static ReturnCode DsmEntry(
 			TWIdentity origin,
 			TWIdentity destination,
@@ -234,6 +246,15 @@ namespace NTwain.Triplets
 			else { return NativeMethods.DsmEntry32(origin, destination, DataGroups.Image, DataArgumentType.ExtImageInfo, msg, data); }
 		}
 
+        public static ReturnCode DsmEntry(
+            TWIdentity origin,
+            TWIdentity destination,
+            Message msg,
+            TWFilter data)
+        {
+            if (Is64Bit) { return NativeMethods.DsmEntry64(origin, destination, DataGroups.Image, DataArgumentType.Filter, msg, data); }
+            else { return NativeMethods.DsmEntry32(origin, destination, DataGroups.Image, DataArgumentType.Filter, msg, data); }
+        }
 
 		public static ReturnCode DsmEntry(
 			TWIdentity origin,

NTwain/Triplets/PInvokes.32bit.cs

@@ -18,6 +18,15 @@ namespace NTwain.Triplets
                 Message msg,
                 ref IntPtr data);
 
+            [DllImport("twain_32", EntryPoint = "#1")]
+            public static extern ReturnCode DsmEntry32(
+                [In, Out]TWIdentity origin,
+                [In, Out]TWIdentity destination,
+                DataGroups dg,
+                DataArgumentType dat,
+                Message msg,
+                ref uint data);
+
 			[DllImport("twain_32", EntryPoint = "#1")]
 			public static extern ReturnCode DsmEntry32(
 				[In, Out]TWIdentity origin,
@@ -180,6 +189,15 @@ namespace NTwain.Triplets
 				Message msg,
                 [In, Out]TWExtImageInfo data);
 
+            [DllImport("twain_32", EntryPoint = "#1")]
+            public static extern ReturnCode DsmEntry32(
+                [In, Out]TWIdentity origin,
+                [In, Out]TWIdentity destination,
+                DataGroups dg,
+                DataArgumentType dat,
+                Message msg,
+                [In, Out]TWFilter data);
+
 			[DllImport("twain_32", EntryPoint = "#1")]
 			public static extern ReturnCode DsmEntry32(
 				[In, Out]TWIdentity origin,

NTwain/Triplets/PInvokes.64bit.cs

@@ -18,6 +18,15 @@ namespace NTwain.Triplets
                 Message msg,
                 ref IntPtr data);
 
+            [DllImport("twaindsm", EntryPoint = "#1")]
+            public static extern ReturnCode DsmEntry64(
+                [In, Out]TWIdentity origin,
+                [In, Out]TWIdentity destination,
+                DataGroups dg,
+                DataArgumentType dat,
+                Message msg,
+                ref uint data);
+
 			[DllImport("twaindsm", EntryPoint = "#1")]
 			public static extern ReturnCode DsmEntry64(
 				[In, Out]TWIdentity origin,
@@ -180,6 +189,15 @@ namespace NTwain.Triplets
 				Message msg,
 				[In, Out]TWExtImageInfo data);
 
+            [DllImport("twaindsm", EntryPoint = "#1")]
+            public static extern ReturnCode DsmEntry64(
+                [In, Out]TWIdentity origin,
+                [In, Out]TWIdentity destination,
+                DataGroups dg,
+                DataArgumentType dat,
+                Message msg,
+                [In, Out]TWFilter data);
+
 			[DllImport("twaindsm", EntryPoint = "#1")]
 			public static extern ReturnCode DsmEntry64(
 				[In, Out]TWIdentity origin,