First attempt on #76 TWFix32 onevalue being wrong.

src/NTwain/Capabilities.cs

@@ -345,12 +345,7 @@ namespace NTwain
         {
             get
             {
-                return _brightness ?? (_brightness = new CapWrapper<TWFix32>(_source, CapabilityId.ICapBrightness, ValueExtensions.ConvertToFix32,
+                return _brightness ?? (_brightness = new CapWrapper<TWFix32>(_source, CapabilityId.ICapBrightness, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 
@@ -366,12 +361,7 @@ namespace NTwain
         {
             get
             {
-                return _contrast ?? (_contrast = new CapWrapper<TWFix32>(_source, CapabilityId.ICapContrast, ValueExtensions.ConvertToFix32,
+                return _contrast ?? (_contrast = new CapWrapper<TWFix32>(_source, CapabilityId.ICapContrast, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 
@@ -408,12 +398,7 @@ namespace NTwain
         {
             get
             {
-                return _exposureTime ?? (_exposureTime = new CapWrapper<TWFix32>(_source, CapabilityId.ICapExposureTime, ValueExtensions.ConvertToFix32,
+                return _exposureTime ?? (_exposureTime = new CapWrapper<TWFix32>(_source, CapabilityId.ICapExposureTime, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 
@@ -450,12 +435,7 @@ namespace NTwain
         {
             get
             {
-                return _gamma ?? (_gamma = new CapWrapper<TWFix32>(_source, CapabilityId.ICapGamma, ValueExtensions.ConvertToFix32,
+                return _gamma ?? (_gamma = new CapWrapper<TWFix32>(_source, CapabilityId.ICapGamma, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 
@@ -487,12 +467,7 @@ namespace NTwain
         {
             get
             {
-                return _highlight ?? (_highlight = new CapWrapper<TWFix32>(_source, CapabilityId.ICapHighlight, ValueExtensions.ConvertToFix32,
+                return _highlight ?? (_highlight = new CapWrapper<TWFix32>(_source, CapabilityId.ICapHighlight, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 
@@ -625,12 +600,7 @@ namespace NTwain
         {
             get
             {
-                return _shadow ?? (_shadow = new CapWrapper<TWFix32>(_source, CapabilityId.ICapShadow, ValueExtensions.ConvertToFix32,
+                return _shadow ?? (_shadow = new CapWrapper<TWFix32>(_source, CapabilityId.ICapShadow, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 
@@ -701,12 +671,7 @@ namespace NTwain
         {
             get
             {
-                return _xResolution ?? (_xResolution = new CapWrapper<TWFix32>(_source, CapabilityId.ICapXResolution, ValueExtensions.ConvertToFix32,
+                return _xResolution ?? (_xResolution = new CapWrapper<TWFix32>(_source, CapabilityId.ICapXResolution, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 
@@ -723,12 +688,7 @@ namespace NTwain
         {
             get
             {
-                return _yResolution ?? (_yResolution = new CapWrapper<TWFix32>(_source, CapabilityId.ICapYResolution, ValueExtensions.ConvertToFix32,
+                return _yResolution ?? (_yResolution = new CapWrapper<TWFix32>(_source, CapabilityId.ICapYResolution, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 
@@ -891,12 +851,7 @@ namespace NTwain
         {
             get
             {
-                return _rotation ?? (_rotation = new CapWrapper<TWFix32>(_source, CapabilityId.ICapRotation, ValueExtensions.ConvertToFix32,
+                return _rotation ?? (_rotation = new CapWrapper<TWFix32>(_source, CapabilityId.ICapRotation, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 
@@ -933,12 +888,7 @@ namespace NTwain
         {
             get
             {
-                return _threshold ?? (_threshold = new CapWrapper<TWFix32>(_source, CapabilityId.ICapThreshold, ValueExtensions.ConvertToFix32,
+                return _threshold ?? (_threshold = new CapWrapper<TWFix32>(_source, CapabilityId.ICapThreshold, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 
@@ -954,12 +904,7 @@ namespace NTwain
         {
             get
             {
-                return _xscaling ?? (_xscaling = new CapWrapper<TWFix32>(_source, CapabilityId.ICapXScaling, ValueExtensions.ConvertToFix32,
+                return _xscaling ?? (_xscaling = new CapWrapper<TWFix32>(_source, CapabilityId.ICapXScaling, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 
@@ -975,12 +920,7 @@ namespace NTwain
         {
             get
             {
-                return _yscaling ?? (_yscaling = new CapWrapper<TWFix32>(_source, CapabilityId.ICapYScaling, ValueExtensions.ConvertToFix32,
+                return _yscaling ?? (_yscaling = new CapWrapper<TWFix32>(_source, CapabilityId.ICapYScaling, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 
@@ -1932,12 +1872,7 @@ namespace NTwain
         {
             get
             {
-                return _mergeHeight ?? (_mergeHeight = new CapWrapper<TWFix32>(_source, CapabilityId.ICapImageMergeHeightThreshold, ValueExtensions.ConvertToFix32,
+                return _mergeHeight ?? (_mergeHeight = new CapWrapper<TWFix32>(_source, CapabilityId.ICapImageMergeHeightThreshold, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 
@@ -3250,12 +3185,7 @@ namespace NTwain
         {
             get
             {
-                return _dblFeedLength ?? (_dblFeedLength = new CapWrapper<TWFix32>(_source, CapabilityId.CapDoubleFeedDetectionLength, ValueExtensions.ConvertToFix32,
+                return _dblFeedLength ?? (_dblFeedLength = new CapWrapper<TWFix32>(_source, CapabilityId.CapDoubleFeedDetectionLength, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 
@@ -3355,12 +3285,7 @@ namespace NTwain
         {
             get
             {
-                return _printVOffset ?? (_printVOffset = new CapWrapper<TWFix32>(_source, CapabilityId.CapPrinterVerticalOffset, ValueExtensions.ConvertToFix32,
+                return _printVOffset ?? (_printVOffset = new CapWrapper<TWFix32>(_source, CapabilityId.CapPrinterVerticalOffset, ValueExtensions.ConvertToFix32, value => value.ToOneValue()));
-                        value => new TWOneValue
-                        {
-                            Item = (uint)value,// ((uint)dpi) << 16;
-                            ItemType = ItemType.Fix32
-                        }));
             }
         }
 

src/NTwain/Data/TwainTypesExtended.cs

@@ -70,6 +70,33 @@ namespace NTwain.Data
             return ToFloat().ToString(CultureInfo.InvariantCulture);
         }
 
+        /// <summary>
+        /// Converts this to <see cref="TWOneValue"/> for capability set methods.
+        /// </summary>
+        /// <returns></returns>
+        public TWOneValue ToOneValue()
+        {
+            // copy struct parts as-is.
+            // probably has a faster way but can't think now
+
+            byte[] array = new byte[4];
+            var part = BitConverter.GetBytes(Whole);
+            Buffer.BlockCopy(part, 0, array, 0, 2);
+
+            part = BitConverter.GetBytes(Fraction);
+            Buffer.BlockCopy(part, 0, array, 2, 2);
+
+            var converted = BitConverter.ToUInt32(array, 0);
+            
+            return new TWOneValue
+            {
+                ItemType = ItemType.Fix32,
+                Item = converted
+                // old wrong conversion
+                // (uint)this,// ((uint)dpi) << 16;
+            };
+        }
+
         #region equals
 
         /// <summary>

src/NTwain/Properties/VersionInfo.cs

@@ -1,6 +1,6 @@
 using System.Reflection;
 
-[assembly: AssemblyCopyright("Copyright \x00a9 Yin-Chun Wang 2012-2016")]
+[assembly: AssemblyCopyright("Copyright \x00a9 Yin-Chun Wang 2012-2017")]
 [assembly: AssemblyCompany("Yin-Chun Wang")]
 
 [assembly: AssemblyVersion(NTwain.VersionInfo.Release)]
@@ -23,7 +23,7 @@ namespace NTwain
         /// <summary>
         /// The build release version number.
         /// </summary>
-        public const string Build = "3.4.0"; // change this for each nuget release
+        public const string Build = "3.4.1"; // change this for each nuget release
 
 
     }