Oftentimes we deal with Hebrew in .NET.

The task we face again and again is attempt to convert a Hebrew text from visual to logical representation.

The latest demand of such task was when we processed content extracted from PDF. It's turned out that PDF stores content as graphic primitives, and as result text is stored visually (often each letter is kept separately).

We solved the task more than a decade ago, by calling Uniscribe API.

The function by itself is a small wrapper around that API, so in .NET 1.0 we were using managed C++, several years later we have switched to C++/CLI.

But now after many .NET releases, and with 32/64 versions we can see that C++ is only a guest in .NET world.

To run C++ in .NET you have to install VC runtime libraries adjusted to a specific .NET version. This turns C++ support in .NET into not a trivial task.

So, we have finally decided to define C# interop for the Uniscribe API, and recreate that function in pure C#:

namespace NesterovskyBros.Bidi
{
  /// <summary>
  /// An utility to convert visual string to logical.
  /// <summary>
  public static class BidiConverter
  {
    /// <summary>
    /// Converts visual string to logical.
    /// </summary>
    /// <param name="value">A value to convert.</param>
    /// <param name="rtl">A base direction.</param>
    /// <param name="direction">
    /// true for visual to logical, and false for logical to visual.
    /// </param>
    /// <returns>Converted string.</returns>
    public static string Convert(string value, bool rtl, bool direction);

You can download this project from BidiVisualConverter.zip.