Using the Skia+WPF head

Uno Platform supports running applications using a WPF shell, using a Skia backend rendering. WPF is used to create a shell for the application to be used on various versions of Windows, going back to Windows 7.

Tip

For a step-by-step guide to installing the prerequisites for your preferred IDE and environment, consult the Get Started guide.

Anatomy of the Skia+WPF project

When creating a Skia+WPF solution, you will get the project head and a Class Library project.

The head project

The project head contains the WPF assets, XAML and C# files for the WPF part of the app (the shell).

The XAML files in this project are using the WPF syntax and APIs, and contain a ContentControl in which the WinUI/Uno content will be drawn.

The Class Library project

The app's Class Library project contains the WinUI part of the app. This is where most of your app code will be located.

Hardware Acceleration

Starting from Uno Platform 4.8, OpenGL acceleration is enabled by default. It is possible to control the render surface type by setting the RenderSurfaceType property.

In the MainWindow.xaml.cs file, change:

root.Content = new global::Uno.UI.Skia.Platform.WpfHost(Dispatcher, () => new MyApp.AppHead());

to:

var host = new global::Uno.UI.Skia.Platform.WpfHost(Dispatcher, () => new MyApp.AppHead());
host.RenderSurfaceType = RenderSurfaceType.Software;

root.Content = host;

Hosting Native WPF Controls

Hosting native WPF controls is supported through ContentPresenter and ContentControl.

See this documentation about embedding native controls.

Upgrading to a later version of SkiaSharp

By default Uno comes with a set of SkiaSharp dependencies set by the Uno.UI.Runtime.Skia.Gtk package.

If you want to upgrade SkiaSharp to a later version, you'll need to specify all packages individually in your project as follows:

<ItemGroup>
   <PackagReference Include="SkiaSharp" Version="2.88.3" /> 
   <PackagReference Include="SkiaSharp.Harfbuzz" Version="2.88.3" /> 
   <PackagReference Include="SkiaSharp.NativeAssets.Linux" Version="2.88.3" /> 
   <PackageReference Update="SkiaSharp.NativeAssets.macOS" Version="2.88.3" />
</ItemGroup>

Upgrading from earlier versions of the Uno Platform template

In previous versions of the Uno Platform template, the Skia+WPF support was split in two projects.

This is not required anymore, but to be able to use a single project, you'll can either:

• Recreate your project from the templates and migrate your code to the new project
• Make some adjustments to your projects:

  1. From the MyProject.Skia.Wpf.csproj :

     • Copy the last <Import Project="..." Label="Shared" /> line to MyProject.Skia.Wpf.csproj
     • Copy the Microsoft.Extensions.Logging and Microsoft.Extensions.Logging.Console lines to MyProject.Skia.Wpf.csproj

  2. Delete the MyProject.Skia.Wpf.csproj

  3. Rename MyProject.Skia.Wpf.Host.csproj to MyProject.Skia.Wpf.csproj

  4. In the MyProject.Shared.projitems, add the following code just before the last </ItemGroup> line:

     <!-- Mark the files from this folder as being part of WinUI -->
     <Page Update="$(MSBuildThisFileDirectory)**/*.xaml" XamlRuntime="WinUI" />
     <ApplicationDefinition Update="$(MSBuildThisFileDirectory)**/*.xaml" XamlRuntime="WinUI" />
     
     <!-- Make sure XAML files force reevaluation of up-to-date checks -->
     <UpToDateCheckInput Include="$(MSBuildThisFileDirectory)**/*.xaml" />
     

     You'll need edit this file outside of Visual Studio. You need an example, create a new temporary project, and take a look at the way these lines are defined in the shared project file.