Fixed wrong assumption of rented array size and added example of usin…

…g non system.drawing image lib.

samples/WinForm32/DsmLoader.cs

@@ -1,4 +1,5 @@
-using System;
+using NTwain.Data;
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -11,8 +12,8 @@ namespace WinFormSample
 {
   /// <summary>
   /// For demoing loading dsm from custom path in case
-  /// it's not installed on system and can't be placed 
-  /// besides the exe.
+  /// it's not installed on system and don't want to be 
+  /// placed besides the exe.
   /// </summary>
   static class DsmLoader
   {
@@ -24,7 +25,7 @@ public static bool TryUseCustomDSM()
       {
         var dll = Path.Combine(
           Path.GetDirectoryName(Environment.ProcessPath ?? Assembly.GetExecutingAssembly().Location)!,
-          "platforms\\TWAINDSM.dll");
+          $@"runtimes\win-{(TwainPlatform.Is32bit ? "x86" : "x64")}\native\TWAINDSM.dll");
 
         __dllPtr = LoadLibraryW(dll);
       }

samples/WinForm32/Form1.cs

@@ -105,11 +105,23 @@ private void Twain_DataTransferred(TwainAppSession sender, DataTransferredEventA
     {
       Debug.WriteLine($"[thread {Environment.CurrentManagedThreadId}] data transferred with info {e.ImageInfo}");
       if (e.Data == null) return;
-      using (var stream = new MemoryStream(e.Data))
-      using (var img = Image.FromStream(stream))
+
+      // example of using some lib to handle image data
+      var saveFile = Path.Combine(saveFolder, (DateTime.Now.Ticks / 1000).ToString());
+      using (var img = new ImageMagick.MagickImage(e.Data))
       {
-        var saveFile = Path.Combine(saveFolder, (DateTime.Now.Ticks / 1000) + ".png");
-        img.Save(saveFile, ImageFormat.Png);
+        if (img.ColorType == ImageMagick.ColorType.Palette)
+        {
+          // bw or gray
+          saveFile += ".png";
+        }
+        else
+        {
+          // color
+          saveFile += ".jpg";
+          img.Quality = 75;
+        }
+        img.Write(saveFile);
         Debug.WriteLine($"Saved image to {saveFile}");
       }
     }
@@ -158,7 +170,7 @@ private void LoadCapInfoList()
       twain.GetCapValues(CAP.CAP_EXTENDEDCAPS, out IList<CAP> extended);
       foreach (var c in caps)
       {
-        ListViewItem it = new(c.ToString());
+        ListViewItem it = new(GetFriendlyName(c));
 
         if (twain.GetCapCurrent(c, out TW_CAPABILITY twcap).RC == TWRC.SUCCESS)
         {
@@ -180,6 +192,15 @@ private void LoadCapInfoList()
       }
     }
 
+    private string GetFriendlyName(CAP c)
+    {
+      if (c > CAP.CAP_CUSTOMBASE)
+      {
+        return $"{CAP.CAP_CUSTOMBASE} + {c - CAP.CAP_CUSTOMBASE}";
+      }
+      return c.ToString();
+    }
+
     // there may be a better way...
     MethodInfo[] twainMethods = typeof(TwainAppSession).GetMethods();
 

samples/WinForm32/WinForm32.csproj

@@ -9,6 +9,10 @@
     <RootNamespace>WinFormSample</RootNamespace>
 	</PropertyGroup>
 
+	<ItemGroup>
+	  <PackageReference Include="Magick.NET-Q8-x86" Version="13.0.1" />
+	</ItemGroup>
+
 	<ItemGroup>
 	  <ProjectReference Include="..\..\src\NTwain\NTwain.csproj" />
 	</ItemGroup>
@@ -17,7 +21,7 @@
 	  <None Update="platforms\qwindows.dll">
 	    <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
 	  </None>
-	  <None Update="platforms\TWAINDSM.dll">
+	  <None Update="runtimes\win-x86\native\TWAINDSM.dll">
 	    <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
 	  </None>
 	</ItemGroup>

samples/WinForm64/WinForm64.csproj

@@ -13,6 +13,10 @@
     <ProjectReference Include="..\..\src\NTwain\NTwain.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Magick.NET-Q8-x64" Version="13.0.1" />
+  </ItemGroup>
+
   <ItemGroup>
     <Compile Include="..\WinForm32\**\*.cs" Exclude="..\WinForm32\**\obj\**;..\WinForm32\**\bin\**">
       <Link>%(RecursiveDir)%(Filename)%(Extension)</Link>
@@ -26,7 +30,7 @@
     <None Update="platforms\qwindows.dll">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
-    <None Update="platforms\TWAINDSM.dll">
+    <None Update="runtimes\win-x64\native\TWAINDSM.dll">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
   </ItemGroup>

src/NTwain/Data/BufferedData.cs

@@ -0,0 +1,31 @@
+using System;
+
+namespace NTwain.Data
+{
+  /// <summary>
+  /// Simple struct with bytes buffer and the valid data length.
+  /// </summary>
+  public struct BufferedData
+  {
+    /// <summary>
+    /// Bytes buffer. This may be bigger than the data size
+    /// and contain invalid data.
+    /// </summary>
+    public byte[]? Buffer;
+
+    /// <summary>
+    /// Actual usable data length in the buffer.
+    /// </summary>
+    public int Length;
+
+    /// <summary>
+    /// As a span of usable data.
+    /// </summary>
+    /// <returns></returns>
+    public ReadOnlySpan<byte> AsSpan()
+    {
+      if (Buffer != null) return Buffer.AsSpan(0, Length);
+      return Span<byte>.Empty;
+    }
+  }
+}

src/NTwain/DataTransferredEventArgs.cs

@@ -13,31 +13,32 @@ public DataTransferredEventArgs(TW_AUDIOINFO info, TW_SETUPFILEXFER fileInfo)
       AudioInfo = info;
       FileInfo = fileInfo;
     }
-    public DataTransferredEventArgs(TW_AUDIOINFO info, byte[] data)
+    public DataTransferredEventArgs(TW_AUDIOINFO info, BufferedData data)
     {
       AudioInfo = info;
-      Data = data;
+      _data = data;
     }
 
-    public DataTransferredEventArgs(TW_IMAGEINFO info, TW_SETUPFILEXFER? fileInfo, byte[]? data)
+    public DataTransferredEventArgs(TW_IMAGEINFO info, TW_SETUPFILEXFER? fileInfo, BufferedData data)
     {
       ImageInfo = info;
       FileInfo = fileInfo;
       IsImage = true;
-      Data = data;
+      _data = data;
     }
 
     /// <summary>
     /// Whether transferred data is an image or audio.
     /// </summary>
     public bool IsImage { get; }
 
+    private readonly BufferedData _data;
     /// <summary>
     /// The complete file data if memory was involved in the transfer. 
     /// IMPORTANT: Content of this array may not valid once
     /// the event handler ends.
     /// </summary>
-    public byte[]? Data { get; }
+    public ReadOnlySpan<byte> Data => _data.AsSpan();
 
     /// <summary>
     /// The file info if the transfer involved file information.

src/NTwain/NTwain.csproj

@@ -13,17 +13,15 @@
     <UseWPF>true</UseWPF>
   </PropertyGroup>
 
-  <ItemGroup>
-  </ItemGroup>
-
   <ItemGroup Condition=" '$(TargetFramework)' == 'net462'">
     <PackageReference Include="Microsoft.CSharp" Version="4.7.0" />
-    <PackageReference Include="System.Buffers" Version="4.5.1" />
+    <!--<PackageReference Include="System.Buffers" Version="4.5.1" />-->
+    <PackageReference Include="System.Memory" Version="4.5.5" />
   </ItemGroup>
   <ItemGroup Condition=" '$(TargetFramework)' != 'net462'">
     <PackageReference Include="System.Text.Encoding.CodePages" Version="7.0.0" />
   </ItemGroup>
-
+  
   <ItemGroup>
     <None Update="DSM\DSMGenerator.dummy">
       <DesignTime>True</DesignTime>

src/NTwain/Native/ImageTools.cs

@@ -1,4 +1,5 @@
-using System;
+using NTwain.Data;
+using System;
 using System.Runtime.InteropServices;
 
 namespace NTwain.Native
@@ -23,15 +24,13 @@ public static bool IsTiff(IntPtr data)
       return test == 0x4949;
     }
 
-
-    public static unsafe byte[]? GetBitmapData(System.Buffers.ArrayPool<byte> xferMemPool, IntPtr data)
+    public static unsafe BufferedData GetBitmapData(System.Buffers.ArrayPool<byte> xferMemPool, IntPtr data)
     {
       var infoHeader = Marshal.PtrToStructure<BITMAPINFOHEADER>(data);
       if (infoHeader.Validate())
       {
         var fileHeaderSize = Marshal.SizeOf(typeof(BITMAPFILEHEADER));
 
-
         var fileHeader = new BITMAPFILEHEADER
         {
           bfType = 0x4D42, // "BM"
@@ -41,7 +40,7 @@ public static bool IsTiff(IntPtr data)
         };
         fileHeader.bfSize = fileHeader.bfOffBits + infoHeader.biSizeImage;
 
-        var dataCopy = xferMemPool.Rent((int)fileHeader.bfSize);// new byte[fileHeader.bfSize];
+        var dataCopy = xferMemPool.Rent((int)fileHeader.bfSize); // new byte[fileHeader.bfSize];
 
         // TODO: run benchmark on which one is faster
 
@@ -59,13 +58,12 @@ public static bool IsTiff(IntPtr data)
 
         // write image
         Marshal.Copy(data, dataCopy, fileHeaderSize, (int)fileHeader.bfSize - fileHeaderSize);
-
-        return dataCopy;
+        return new BufferedData { Buffer = dataCopy, Length = (int)fileHeader.bfSize };
       }
-      return null;
+      return default;
     }
 
-    public static byte[]? GetTiffData(System.Buffers.ArrayPool<byte> xferMemPool, IntPtr data)
+    public static BufferedData GetTiffData(System.Buffers.ArrayPool<byte> xferMemPool, IntPtr data)
     {
       // Find the size of the image so we can turn it into a memory stream...
       var headerSize = Marshal.SizeOf(typeof(TIFFHEADER));
@@ -91,9 +89,9 @@ public static bool IsTiff(IntPtr data)
         var dataCopy = xferMemPool.Rent(tiffSize);// new byte[tiffSize];
         // is this optimal?
         Marshal.Copy(data, dataCopy, 0, tiffSize);
-        return dataCopy;
+        return new BufferedData { Buffer = dataCopy, Length = tiffSize };
       }
-      return null;
+      return default;
     }
 
     //internal static Bitmap ReadBitmapImage(IntPtr data)

src/NTwain/TwainAppSession.Xfers.cs

@@ -10,6 +10,7 @@
 using System.Runtime.InteropServices;
 using System.Threading;
 using System.Xml.Serialization;
+using static NTwain.Native.ImageTools;
 
 namespace NTwain
 {
@@ -66,7 +67,7 @@ void EnterTransferRoutine()
         do
         {
           var readyArgs = new TransferReadyEventArgs(pending.Count, (TWEJ)pending.EOJ);
-          _uiThreadMarshaller.Invoke((ref TW_PENDINGXFERS pending) =>
+          _uiThreadMarshaller.Invoke(() =>
           {
             try
             {
@@ -159,7 +160,7 @@ void EnterTransferRoutine()
 
       if (State >= STATE.S5)
       {
-        _uiThreadMarshaller.BeginInvoke((ref TW_PENDINGXFERS pending) =>
+        _uiThreadMarshaller.BeginInvoke(() =>
         {
           DisableSource();
         });
@@ -245,11 +246,11 @@ private STS TransferNativeAudio(ref TW_PENDINGXFERS pending)
         {
           State = STATE.S7;
           lockedPtr = Lock(dataPtr);
-          byte[]? data = null;
+          BufferedData data = default;
 
           // TODO: don't know how to read wav/aiff from pointer yet
 
-          if (data != null)
+          if (data.Buffer != null)
           {
             try
             {
@@ -260,7 +261,7 @@ private STS TransferNativeAudio(ref TW_PENDINGXFERS pending)
             catch { }
             finally
             {
-              XferMemPool.Return(data);
+              XferMemPool.Return(data.Buffer);
             }
           }
         }
@@ -420,7 +421,7 @@ private STS TransferMemoryFileImage(ref TW_PENDINGXFERS pending)
         {
           DGImage.ImageInfo.Get(ref _appIdentity, ref _currentDS, out TW_IMAGEINFO info);
           // ToArray bypasses the XferMemPool but I guess this will have to do for now
-          var args = new DataTransferredEventArgs(info, fileSetup, outStream.ToArray());
+          var args = new DataTransferredEventArgs(info, fileSetup, new BufferedData { Buffer = outStream.ToArray(), Length = (int)outStream.Length });
           DataTransferred?.Invoke(this, args);
         }
         catch { }
@@ -448,7 +449,7 @@ private STS TransferFileImage(ref TW_PENDINGXFERS pending)
         try
         {
           DGImage.ImageInfo.Get(ref _appIdentity, ref _currentDS, out TW_IMAGEINFO info);
-          var args = new DataTransferredEventArgs(info, fileSetup, null);
+          var args = new DataTransferredEventArgs(info, fileSetup, default);
           DataTransferred?.Invoke(this, args);
         }
         catch { }
@@ -473,8 +474,7 @@ private STS TransferNativeImage(ref TW_PENDINGXFERS pending)
         {
           State = STATE.S7;
           lockedPtr = Lock(dataPtr);
-          byte[]? data = null;
-
+          BufferedData data = default;
 
           if (ImageTools.IsDib(lockedPtr))
           {
@@ -490,7 +490,7 @@ private STS TransferNativeImage(ref TW_PENDINGXFERS pending)
             // don't support more formats :(
           }
 
-          if (data != null)
+          if (data.Buffer != null)
           {
             try
             {
@@ -501,7 +501,7 @@ private STS TransferNativeImage(ref TW_PENDINGXFERS pending)
             catch { }
             finally
             {
-              XferMemPool.Return(data);
+              XferMemPool.Return(data.Buffer);
             }
           }