Add .Net Core 3 support

I got a closed source project where i got a wpf app that uses magick.net to load and display images in xaml by loading them in the background and converting to something wpf can display with

                var data = default(byte[]); // not actual initialization logic, but simply for showing the datatype
                using (var img = new MagickImage(data))
                {
                    source = img.ToBitmapSource();
                    source.Freeze();
                }

When i migrated that project to netcoreapp3.0, i noticed, that that img.ToBitmapSource(); is not available to me anymore, when using Magick.NET-Q8-AnyCPU with version 7.11.1.

I imagine, adding the appropriate preprocessor directive to MagickImage.cs might already be enough to fix my issue.

This fix would add the .net core 3 sdk (preview) as dependency and require the usage of Visual Studio 2019 (preview) or rather the corresponding msbuild version to be installed locally. So i do understand if this isnt going to happen right away.

I am happy to provide further details when required.

[dlemstra]

The ToBitmap and ToBitmapSource methods have been moved to new separate libraries called Magick.NET.SystemDrawing and Magick.NET.SystemWindowsMedia. The Magick.NET.SystemDrawing library has support for netstandard20. But that has not been done for the Magick.NET.SystemWindowsMedia library. I don’t know which dependency I need to add to make it work. Only targetting netcoreapp3.0 does not seem to work.

[Insire]

I just tried it and used

        <TargetFrameworks>netcoreapp3.1</TargetFrameworks>

... 

        <PackageReference Include="Magick.NET-Q8-AnyCPU" Version="7.19.0" />
        <PackageReference Include="Magick.NET.SystemWindowsMedia" Version="1.0.1" />

which worked as expected in a .net core app using

        using ImageMagick;

        private static BitmapSource GetImage(string path)
        {
            using (var stream = File.OpenRead(path))
            using (var img = new MagickImage(stream))
            {
                var source = img.ToBitmapSource();
                source.Freeze();

                return source;
            }
        }