feat(skiasharp): add a Skia bitmap loader package

src/Directory.Packages.props

@@ -28,6 +28,9 @@
     <PackageVersion Include="Serilog.Exceptions" Version="8.4.0" />
     <PackageVersion Include="SonarAnalyzer.CSharp" Version="10.31.0.145097" />
     <PackageVersion Include="SimpleInjector" Version="5.6.0" />
+    <PackageVersion Include="SkiaSharp" Version="4.151.0" />
+    <!-- SkiaSharp brings only the macOS and Win32 native assets on the plain .NET target frameworks. -->
+    <PackageVersion Include="SkiaSharp.NativeAssets.Linux.NoDependencies" Version="4.151.0" />
     <!-- StyleSharp.Analyzers, PerformanceSharp.Analyzers and SecuritySharp.Analyzers ship from the
          same release pipeline and always share a version. -->
     <PackageVersion Include="StyleSharp.Analyzers" Version="3.40.1" />

src/Splat.SkiaSharp/BitmapMixins.cs

@@ -0,0 +1,40 @@
+// Copyright (c) 2019-2026 ReactiveUI Association Incorporated. All rights reserved.
+// ReactiveUI Association Incorporated licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+using SkiaSharp;
+
+namespace Splat.SkiaSharp;
+
+/// <summary>Converts between <see cref="IBitmap"/> and the Skia bitmap behind it.</summary>
+/// <remarks>
+/// Skia is not the host's imaging stack, and these conversions do not pretend otherwise: what comes
+/// back is an <see cref="SKBitmap"/>, not a platform bitmap type.
+/// </remarks>
+public static class BitmapMixins
+{
+    /// <summary>Extension members for <see cref="IBitmap"/>.</summary>
+    /// <param name="value">The value the extension members operate on.</param>
+    extension(IBitmap value)
+    {
+        /// <summary>Gets the Skia bitmap behind an <see cref="IBitmap"/> this package produced.</summary>
+        /// <returns>The Skia bitmap, which the <see cref="IBitmap"/> still owns.</returns>
+        /// <exception cref="InvalidOperationException">The bitmap has been disposed.</exception>
+        /// <exception cref="InvalidCastException">The bitmap came from a different loader.</exception>
+        public SKBitmap ToNative()
+        {
+            ArgumentExceptionHelper.ThrowIfNull(value);
+
+            return ((SkiaBitmap)value).Inner ?? throw new InvalidOperationException("The bitmap has been disposed");
+        }
+    }
+
+    /// <summary>Extension members for <see cref="SKBitmap"/>.</summary>
+    /// <param name="value">The value the extension members operate on.</param>
+    extension(SKBitmap value)
+    {
+        /// <summary>Wraps a Skia bitmap as an <see cref="IBitmap"/>, taking ownership of it.</summary>
+        /// <returns>The wrapped bitmap.</returns>
+        public IBitmap FromNative() => new SkiaBitmap(value);
+    }
+}

src/Splat.SkiaSharp/Builder/SkiaSharpSplatModule.cs

@@ -0,0 +1,38 @@
+// Copyright (c) 2019-2026 ReactiveUI Association Incorporated. All rights reserved.
+// ReactiveUI Association Incorporated licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+using SkiaSharp;
+
+using Splat.SkiaSharp;
+
+namespace Splat.Builder;
+
+/// <summary>Registers Skia as the bitmap loader when the application is built.</summary>
+/// <remarks>
+/// Registration is a plain method call rather than assembly scanning, so it survives trimming and
+/// ahead-of-time compilation.
+/// </remarks>
+/// <param name="sampling">The sampling to resize with, or <see langword="null"/> for the loader's default.</param>
+public sealed class SkiaSharpSplatModule(SKSamplingOptions? sampling) : IModule
+{
+    /// <summary>Initializes a new instance of the <see cref="SkiaSharpSplatModule"/> class.</summary>
+    public SkiaSharpSplatModule()
+        : this(null)
+    {
+    }
+
+    /// <inheritdoc />
+    public void Configure(IMutableDependencyResolver resolver)
+    {
+        ArgumentExceptionHelper.ThrowIfNull(resolver);
+
+        if (sampling is null)
+        {
+            resolver.UseSkiaSharpBitmapLoader();
+            return;
+        }
+
+        resolver.UseSkiaSharpBitmapLoader(sampling.Value);
+    }
+}

src/Splat.SkiaSharp/MutableDependencyResolverExtensions.cs

@@ -0,0 +1,43 @@
+// Copyright (c) 2019-2026 ReactiveUI Association Incorporated. All rights reserved.
+// ReactiveUI Association Incorporated licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+using SkiaSharp;
+
+namespace Splat.SkiaSharp;
+
+/// <summary>Registers Skia as the bitmap loader Splat resolves.</summary>
+/// <remarks>
+/// The plain .NET target frameworks register no bitmap loader of their own, so <see cref="BitmapLoader.Current"/>
+/// throws until something is registered. Registration is explicit: nothing scans assemblies for it.
+/// </remarks>
+public static class MutableDependencyResolverExtensions
+{
+    /// <summary>Extension members for <see cref="IMutableDependencyResolver"/>.</summary>
+    /// <param name="instance">An instance of Mutable Dependency Resolver.</param>
+    extension(IMutableDependencyResolver instance)
+    {
+        /// <summary>Registers <see cref="SkiaBitmapLoader"/> as the <see cref="IBitmapLoader"/>.</summary>
+        /// <example>
+        /// <c>AppLocator.CurrentMutable.UseSkiaSharpBitmapLoader();</c>
+        /// </example>
+        public void UseSkiaSharpBitmapLoader()
+        {
+            ArgumentExceptionHelper.ThrowIfNull(instance);
+
+            instance.RegisterLazySingleton(static () => new SkiaBitmapLoader(), typeof(IBitmapLoader));
+        }
+
+        /// <summary>Registers <see cref="SkiaBitmapLoader"/> as the <see cref="IBitmapLoader"/>, resizing with the given sampling.</summary>
+        /// <param name="sampling">The sampling to resize with.</param>
+        /// <example>
+        /// <c>AppLocator.CurrentMutable.UseSkiaSharpBitmapLoader(new SKSamplingOptions(SKFilterMode.Nearest));</c>
+        /// </example>
+        public void UseSkiaSharpBitmapLoader(SKSamplingOptions sampling)
+        {
+            ArgumentExceptionHelper.ThrowIfNull(instance);
+
+            instance.RegisterLazySingleton(() => new SkiaBitmapLoader(sampling), typeof(IBitmapLoader));
+        }
+    }
+}

src/Splat.SkiaSharp/PublicAPI/net10.0/PublicAPI.txt

@@ -0,0 +1,53 @@
+[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("Splat.SkiaSharp.Tests")]
+namespace Splat.Builder
+{
+    public sealed class SkiaSharpSplatModule : Splat.Builder.IModule
+    {
+        public SkiaSharpSplatModule() { }
+        public SkiaSharpSplatModule(SkiaSharp.SKSamplingOptions? sampling) { }
+        public void Configure(Splat.IMutableDependencyResolver resolver) { }
+    }
+}
+namespace Splat.SkiaSharp
+{
+    public static class BitmapMixins
+    {
+        extension(SkiaSharp.SKBitmap value)
+        {
+            public Splat.IBitmap FromNative() { }
+        }
+        extension(Splat.IBitmap value)
+        {
+            public SkiaSharp.SKBitmap ToNative() { }
+        }
+    }
+    public static class MutableDependencyResolverExtensions
+    {
+        extension(Splat.IMutableDependencyResolver instance)
+        {
+            public void UseSkiaSharpBitmapLoader() { }
+            public void UseSkiaSharpBitmapLoader(SkiaSharp.SKSamplingOptions sampling) { }
+        }
+    }
+    public sealed class SkiaBitmap : Splat.IBitmap
+    {
+        public SkiaBitmap(SkiaSharp.SKBitmap bitmap) { }
+        public SkiaBitmap(SkiaSharp.SKBitmap bitmap, SkiaSharp.SKEncodedOrigin encodedOrigin) { }
+        public SkiaSharp.SKEncodedOrigin EncodedOrigin { get; }
+        public float Height { get; }
+        public SkiaSharp.SKBitmap? Inner { get; }
+        public float Width { get; }
+        public void Dispose() { }
+        public System.Threading.Tasks.Task Save(SkiaSharp.SKEncodedImageFormat format, float quality, System.IO.Stream target) { }
+        public System.Threading.Tasks.Task Save(Splat.CompressedBitmapFormat format, float quality, System.IO.Stream target) { }
+    }
+    public sealed class SkiaBitmapLoader : Splat.IBitmapLoader
+    {
+        public SkiaBitmapLoader() { }
+        public SkiaBitmapLoader(SkiaSharp.SKSamplingOptions sampling) { }
+        public SkiaSharp.SKSamplingOptions Sampling { get; }
+        public Splat.IBitmap Create(float width, float height) { }
+        public System.Threading.Tasks.Task<Splat.IBitmap?> Load(System.IO.Stream sourceStream, float? desiredWidth, float? desiredHeight) { }
+        public System.Threading.Tasks.Task<Splat.IBitmap?> LoadFromResource(string source, float? desiredWidth, float? desiredHeight) { }
+    }
+}

src/Splat.SkiaSharp/PublicAPI/net11.0/PublicAPI.txt

@@ -0,0 +1,53 @@
+[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("Splat.SkiaSharp.Tests")]
+namespace Splat.Builder
+{
+    public sealed class SkiaSharpSplatModule : Splat.Builder.IModule
+    {
+        public SkiaSharpSplatModule() { }
+        public SkiaSharpSplatModule(SkiaSharp.SKSamplingOptions? sampling) { }
+        public void Configure(Splat.IMutableDependencyResolver resolver) { }
+    }
+}
+namespace Splat.SkiaSharp
+{
+    public static class BitmapMixins
+    {
+        extension(SkiaSharp.SKBitmap value)
+        {
+            public Splat.IBitmap FromNative() { }
+        }
+        extension(Splat.IBitmap value)
+        {
+            public SkiaSharp.SKBitmap ToNative() { }
+        }
+    }
+    public static class MutableDependencyResolverExtensions
+    {
+        extension(Splat.IMutableDependencyResolver instance)
+        {
+            public void UseSkiaSharpBitmapLoader() { }
+            public void UseSkiaSharpBitmapLoader(SkiaSharp.SKSamplingOptions sampling) { }
+        }
+    }
+    public sealed class SkiaBitmap : Splat.IBitmap
+    {
+        public SkiaBitmap(SkiaSharp.SKBitmap bitmap) { }
+        public SkiaBitmap(SkiaSharp.SKBitmap bitmap, SkiaSharp.SKEncodedOrigin encodedOrigin) { }
+        public SkiaSharp.SKEncodedOrigin EncodedOrigin { get; }
+        public float Height { get; }
+        public SkiaSharp.SKBitmap? Inner { get; }
+        public float Width { get; }
+        public void Dispose() { }
+        public System.Threading.Tasks.Task Save(SkiaSharp.SKEncodedImageFormat format, float quality, System.IO.Stream target) { }
+        public System.Threading.Tasks.Task Save(Splat.CompressedBitmapFormat format, float quality, System.IO.Stream target) { }
+    }
+    public sealed class SkiaBitmapLoader : Splat.IBitmapLoader
+    {
+        public SkiaBitmapLoader() { }
+        public SkiaBitmapLoader(SkiaSharp.SKSamplingOptions sampling) { }
+        public SkiaSharp.SKSamplingOptions Sampling { get; }
+        public Splat.IBitmap Create(float width, float height) { }
+        public System.Threading.Tasks.Task<Splat.IBitmap?> Load(System.IO.Stream sourceStream, float? desiredWidth, float? desiredHeight) { }
+        public System.Threading.Tasks.Task<Splat.IBitmap?> LoadFromResource(string source, float? desiredWidth, float? desiredHeight) { }
+    }
+}

src/Splat.SkiaSharp/PublicAPI/net8.0/PublicAPI.txt

@@ -0,0 +1,53 @@
+[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("Splat.SkiaSharp.Tests")]
+namespace Splat.Builder
+{
+    public sealed class SkiaSharpSplatModule : Splat.Builder.IModule
+    {
+        public SkiaSharpSplatModule() { }
+        public SkiaSharpSplatModule(SkiaSharp.SKSamplingOptions? sampling) { }
+        public void Configure(Splat.IMutableDependencyResolver resolver) { }
+    }
+}
+namespace Splat.SkiaSharp
+{
+    public static class BitmapMixins
+    {
+        extension(SkiaSharp.SKBitmap value)
+        {
+            public Splat.IBitmap FromNative() { }
+        }
+        extension(Splat.IBitmap value)
+        {
+            public SkiaSharp.SKBitmap ToNative() { }
+        }
+    }
+    public static class MutableDependencyResolverExtensions
+    {
+        extension(Splat.IMutableDependencyResolver instance)
+        {
+            public void UseSkiaSharpBitmapLoader() { }
+            public void UseSkiaSharpBitmapLoader(SkiaSharp.SKSamplingOptions sampling) { }
+        }
+    }
+    public sealed class SkiaBitmap : Splat.IBitmap
+    {
+        public SkiaBitmap(SkiaSharp.SKBitmap bitmap) { }
+        public SkiaBitmap(SkiaSharp.SKBitmap bitmap, SkiaSharp.SKEncodedOrigin encodedOrigin) { }
+        public SkiaSharp.SKEncodedOrigin EncodedOrigin { get; }
+        public float Height { get; }
+        public SkiaSharp.SKBitmap? Inner { get; }
+        public float Width { get; }
+        public void Dispose() { }
+        public System.Threading.Tasks.Task Save(SkiaSharp.SKEncodedImageFormat format, float quality, System.IO.Stream target) { }
+        public System.Threading.Tasks.Task Save(Splat.CompressedBitmapFormat format, float quality, System.IO.Stream target) { }
+    }
+    public sealed class SkiaBitmapLoader : Splat.IBitmapLoader
+    {
+        public SkiaBitmapLoader() { }
+        public SkiaBitmapLoader(SkiaSharp.SKSamplingOptions sampling) { }
+        public SkiaSharp.SKSamplingOptions Sampling { get; }
+        public Splat.IBitmap Create(float width, float height) { }
+        public System.Threading.Tasks.Task<Splat.IBitmap?> Load(System.IO.Stream sourceStream, float? desiredWidth, float? desiredHeight) { }
+        public System.Threading.Tasks.Task<Splat.IBitmap?> LoadFromResource(string source, float? desiredWidth, float? desiredHeight) { }
+    }
+}

src/Splat.SkiaSharp/PublicAPI/net9.0/PublicAPI.txt

@@ -0,0 +1,53 @@
+[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("Splat.SkiaSharp.Tests")]
+namespace Splat.Builder
+{
+    public sealed class SkiaSharpSplatModule : Splat.Builder.IModule
+    {
+        public SkiaSharpSplatModule() { }
+        public SkiaSharpSplatModule(SkiaSharp.SKSamplingOptions? sampling) { }
+        public void Configure(Splat.IMutableDependencyResolver resolver) { }
+    }
+}
+namespace Splat.SkiaSharp
+{
+    public static class BitmapMixins
+    {
+        extension(SkiaSharp.SKBitmap value)
+        {
+            public Splat.IBitmap FromNative() { }
+        }
+        extension(Splat.IBitmap value)
+        {
+            public SkiaSharp.SKBitmap ToNative() { }
+        }
+    }
+    public static class MutableDependencyResolverExtensions
+    {
+        extension(Splat.IMutableDependencyResolver instance)
+        {
+            public void UseSkiaSharpBitmapLoader() { }
+            public void UseSkiaSharpBitmapLoader(SkiaSharp.SKSamplingOptions sampling) { }
+        }
+    }
+    public sealed class SkiaBitmap : Splat.IBitmap
+    {
+        public SkiaBitmap(SkiaSharp.SKBitmap bitmap) { }
+        public SkiaBitmap(SkiaSharp.SKBitmap bitmap, SkiaSharp.SKEncodedOrigin encodedOrigin) { }
+        public SkiaSharp.SKEncodedOrigin EncodedOrigin { get; }
+        public float Height { get; }
+        public SkiaSharp.SKBitmap? Inner { get; }
+        public float Width { get; }
+        public void Dispose() { }
+        public System.Threading.Tasks.Task Save(SkiaSharp.SKEncodedImageFormat format, float quality, System.IO.Stream target) { }
+        public System.Threading.Tasks.Task Save(Splat.CompressedBitmapFormat format, float quality, System.IO.Stream target) { }
+    }
+    public sealed class SkiaBitmapLoader : Splat.IBitmapLoader
+    {
+        public SkiaBitmapLoader() { }
+        public SkiaBitmapLoader(SkiaSharp.SKSamplingOptions sampling) { }
+        public SkiaSharp.SKSamplingOptions Sampling { get; }
+        public Splat.IBitmap Create(float width, float height) { }
+        public System.Threading.Tasks.Task<Splat.IBitmap?> Load(System.IO.Stream sourceStream, float? desiredWidth, float? desiredHeight) { }
+        public System.Threading.Tasks.Task<Splat.IBitmap?> LoadFromResource(string source, float? desiredWidth, float? desiredHeight) { }
+    }
+}