csharp-message-to-image-library

csharp-message-to-image-library is a test/sample C# solution with an ordinary (non-MFC) C++ DLL project.

The purpose of this solution is to work out how to create a C++ DLL and utilise it in C#.

This repository is an off-shoot of csharp-stream-controller

Direct2DWrapper

This project is a non-MFC C++ DLL project.

It exports a limited number of functions that are abstractions of some Direct2D and DirectWrite functions.

MessageToImageLibrary

This is the main C# WPF .NET Core 3.1 project.

It is (now) a C# wrapper around Direct2DWrapper providing a limited set of features so that a message (such as a Tweet) can be transformed into a PNG file.

In order to use the library, the Direct2DWrapper project will need building to generate Direct2DWrapper.dll and a link file created in MessageToImageLibrary\lib pointing at the Direct2DWrapper.dll file.

Direct2DWrapper.dll

The C# project needs to be able to find Direct2DWrapper.dll.

1. In Visual Studio 2019, choose Debug or Release for Solution Configurations and x64 or x86 for Solution Platforms.
2. Right-click the Direct2DWrapper project and click Build.
3. Right-click the lib folder in the MessageToImageLibrary project.
4. In the context menu: Add, Existing Item…
5. Change the file types drop down to Executable Files (or all files, you're looking for a .dll)
6. Browse to the root directory for the solution - if you're in the directory csharp-message-to-image-library\MessageToImageLibrary, you need to go up a directory.
7. Find the DLL you built in step 1. If you chose Debug and x64, it will likely be in x64\Debug. Select the Direct2DWrapper.dll file.
8. Click the arrow next to the Add button, and click Add as Link.
9. Right-click the link file lib\Direct2DWrapper.dll and click Properties.
10. Change Copy to Output Directory to Copy if newer.
11. Run the MessageToImageLibrary project. If something is still wrong, you'll get a DllNotFoundException.

Expected Output

MessageToImageLibrary exports a generic Add(int a, double b) function found in Direct2DWrapper.

If the projects are built correctly, the Visual Studio debug Output window should include the following output on instantiation of a C# MessageToImageLibrary.Direct2DWrapper instance:

Result of external Add(10, 3) = 13.

class Test()
{
    private readonly MessageToImageLibrary.Direct2DWrapper d2dWrapper;

    Test()
    {
        Trace.WriteLine("Testing DLL...");
        d2dWrapper = new MessageToImageLibrary.Direct2DWrapper();
    }
}

The expected output listed above may be out of date as documentation changes typically lag code changes. Check recent commits for changes.