Make API public

Author: JimBobSquarePants

ImageSharp.Drawing.sln

@@ -457,6 +457,7 @@ Global
 		SolutionGuid = {5F8B9D1F-CD8B-4CC5-8216-D531E25BD795}
 	EndGlobalSection
 	GlobalSection(SharedMSBuildProjectFiles) = preSolution
+		shared-infrastructure\src\SharedInfrastructure\SharedInfrastructure.projitems*{061582c2-658f-40ae-a978-7d74a4eb2c0a}*SharedItemsImports = 5
 		shared-infrastructure\src\SharedInfrastructure\SharedInfrastructure.projitems*{2e33181e-6e28-4662-a801-e2e7dc206029}*SharedItemsImports = 5
 		shared-infrastructure\src\SharedInfrastructure\SharedInfrastructure.projitems*{68a8cc40-6aed-4e96-b524-31b1158fdeea}*SharedItemsImports = 13
 	EndGlobalSection

samples/WebGPUWindowDemo/Program.cs

@@ -12,7 +12,6 @@
 using SixLabors.ImageSharp.Drawing.Processing;
 using SixLabors.ImageSharp.Drawing.Processing.Backends;
 using SixLabors.ImageSharp.Drawing.Text;
-using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.PixelFormats;
 using Color = SixLabors.ImageSharp.Color;
 using Rectangle = SixLabors.ImageSharp.Rectangle;
@@ -59,7 +58,7 @@ public static unsafe class Program
     // Scrolling text state — glyph geometry is built once at startup via TextBuilder
     // and translated vertically each frame. Only glyphs whose bounds intersect the
     // visible viewport are submitted for rasterization.
-    private static IPathCollection scrollPaths = null!;
+    private static IPathCollection scrollPaths;
     private static float scrollOffset;
     private static float scrollTextHeight;
     private const string ScrollText =
@@ -156,10 +155,6 @@ private static void OnLoad()
 
         Console.WriteLine($"Device: 0x{(nuint)device:X}, Queue: 0x{(nuint)queue:X}");
 
-        // Register shared handles so the drawing backend uses our device rather than
-        // provisioning its own.
-        WebGPURuntime.SetSharedHandles((nint)device, (nint)queue);
-
         // Query surface capabilities and configure the swap chain.
         wgpu.SurfaceGetCapabilities(surface, adapter, ref surfaceCapabilities);
         Console.WriteLine($"Surface format: {surfaceCapabilities.Formats[0]}");
@@ -292,14 +287,11 @@ private static void OnRender(double deltaTime)
                 (nint)textureView,
                 WebGPUTextureFormatId.Bgra8Unorm,
                 w,
-                h,
-                isSrgb: false,
-                isPremultipliedAlpha: false,
-                supportsTextureSampling: true);
+                h);
 
-            // NativeSurfaceOnlyFrame exposes only the GPU surface (no CPU region),
+            // NativeCanvasFrame exposes only the GPU surface (no CPU region),
             // so the backend always takes the GPU composition path.
-            NativeSurfaceOnlyFrame<Bgra32> frame = new(new Rectangle(0, 0, w, h), nativeSurface);
+            NativeCanvasFrame<Bgra32> frame = new(new Rectangle(0, 0, w, h), nativeSurface);
 
             // Create a drawing canvas targeting the swap chain frame.
             using DrawingCanvas<Bgra32> canvas = new(drawingConfiguration, frame, new DrawingOptions());
@@ -389,15 +381,12 @@ private static void DrawScrollingText(DrawingCanvas<Bgra32> canvas, int w, int h
     private static void OnClosing()
     {
         backend.Dispose();
-        WebGPURuntime.ClearSharedHandles();
 
         wgpu.DeviceRelease(device);
         wgpu.AdapterRelease(adapter);
         wgpu.SurfaceRelease(surface);
         wgpu.InstanceRelease(instance);
         wgpu.Dispose();
-
-        WebGPURuntime.Shutdown();
     }
 
     /// <summary>WebGPU device-lost callback — logs the reason to the console.</summary>
@@ -408,37 +397,6 @@ private static void DeviceLost(DeviceLostReason reason, byte* message, void* use
     private static void UncapturedError(ErrorType type, byte* message, void* userData)
         => Console.WriteLine($"WebGPU {type}: {SilkMarshal.PtrToString((nint)message)}");
 
-    /// <summary>
-    /// Wraps a <see cref="NativeSurface"/> as an <see cref="ICanvasFrame{TPixel}"/> that
-    /// exposes only the GPU surface. <see cref="TryGetCpuRegion"/> returns false, ensuring
-    /// the drawing backend always takes the native GPU composition path.
-    /// </summary>
-    private sealed class NativeSurfaceOnlyFrame<TPixel> : ICanvasFrame<TPixel>
-        where TPixel : unmanaged, IPixel<TPixel>
-    {
-        private readonly NativeSurface nativeSurface;
-
-        public NativeSurfaceOnlyFrame(Rectangle bounds, NativeSurface nativeSurface)
-        {
-            this.Bounds = bounds;
-            this.nativeSurface = nativeSurface;
-        }
-
-        public Rectangle Bounds { get; }
-
-        public bool TryGetCpuRegion(out Buffer2DRegion<TPixel> region)
-        {
-            region = default;
-            return false;
-        }
-
-        public bool TryGetNativeSurface(out NativeSurface surface)
-        {
-            surface = this.nativeSurface;
-            return true;
-        }
-    }
-
     /// <summary>
     /// A simple bouncing ball with position, velocity, radius, and color.
     /// Reflects off the window edges each frame.

src/Directory.Build.props

@@ -30,7 +30,6 @@
     <InternalsVisibleTo Include="DynamicProxyGenAssembly2" Key="0024000004800000940000000602000000240000525341310004000001000100c547cac37abd99c8db225ef2f6c8a3602f3b3606cc9891605d02baa56104f4cfc0734aa39b93bf7852f7d9266654753cc297e7d2edfe0bac1cdcf9f717241550e0a7b191195b7667bb4f64bcb8e2121380fd1d9d46ad2d92d2d15605093924cceaf74c4861eff62abf69b9291ed0a340e113be11e6a7d3113e92484cf7045cc7" />
     <InternalsVisibleTo Include="SixLabors.ImageSharp.Tests"  Key="$(SixLaborsPublicKey)" />
     <InternalsVisibleTo Include="ImageSharp.Drawing.Benchmarks"  Key="$(SixLaborsPublicKey)" />
-    <InternalsVisibleTo Include="WebGPUWindowDemo"  Key="$(SixLaborsPublicKey)" />
   </ItemGroup>
 
 </Project>

src/ImageSharp.Drawing.WebGPU/ImageSharp.Drawing.WebGPU.csproj

@@ -67,6 +67,8 @@
     <PackageReference Include="Silk.NET.WebGPU.Native.WGPU" Version="2.23.0" PrivateAssets="compile;build;analyzers;contentfiles;buildtransitive" />
   </ItemGroup>
 
+  <Import Project="..\..\shared-infrastructure\src\SharedInfrastructure\SharedInfrastructure.projitems" Label="Shared" />
+
   <ItemGroup>
     <ProjectReference Include="..\ImageSharp.Drawing\ImageSharp.Drawing.csproj" />
   </ItemGroup>

src/ImageSharp.Drawing.WebGPU/WebGPUDrawingBackend.CompositePixels.cs

@@ -17,7 +17,7 @@ namespace SixLabors.ImageSharp.Drawing.Processing.Backends;
 /// Only formats that support <c>storage</c> texture binding (required by the compute compositor)
 /// are included. Formats that lack storage support are omitted and fall back to the CPU backend.
 /// </remarks>
-internal sealed partial class WebGPUDrawingBackend
+public sealed partial class WebGPUDrawingBackend
 {
     /// <summary>
     /// Builds the static registration table that maps <see cref="IPixel{TSelf}"/> implementations to
@@ -27,9 +27,6 @@ internal sealed partial class WebGPUDrawingBackend
     private static Dictionary<Type, CompositePixelRegistration> CreateCompositePixelHandlers() =>
 
         // Only formats with native or feature-gated storage binding support.
-        // Non-storable formats (R8Unorm, RG8Unorm, RG8Snorm, R16Float, RG16Float,
-        // RG16Sint, Rgb10A2Unorm, R16Uint, RG16Uint) are omitted — they cannot be
-        // used as compute shader write targets and fall back to DefaultDrawingBackend.
         new()
         {
             [typeof(Byte4)] = CompositePixelRegistration.Create<Byte4>(TextureFormat.Rgba8Uint),
@@ -47,13 +44,12 @@ private static Dictionary<Type, CompositePixelRegistration> CreateCompositePixel
         };
 
     /// <summary>
-    /// Resolves the WebGPU texture format identifier for <typeparamref name="TPixel"/> when supported
-    /// by the current device.
+    /// Resolves the WebGPU texture format identifier for <typeparamref name="TPixel"/>.
     /// </summary>
     /// <typeparam name="TPixel">The requested pixel type.</typeparam>
     /// <param name="formatId">Receives the mapped texture format identifier on success.</param>
     /// <returns>
-    /// <see langword="true"/> when the pixel type is supported for GPU composition; otherwise <see langword="false"/>.
+    /// <see langword="true"/> when the pixel type has a registered GPU format mapping; otherwise <see langword="false"/>.
     /// </returns>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     internal static bool TryGetCompositeTextureFormat<TPixel>(out WebGPUTextureFormatId formatId)
@@ -65,14 +61,36 @@ internal static bool TryGetCompositeTextureFormat<TPixel>(out WebGPUTextureForma
             return false;
         }
 
-        if (registration.RequiredFeature != FeatureName.Undefined
-            && !WebGPURuntime.HasDeviceFeature(registration.RequiredFeature))
+        formatId = WebGPUTextureFormatMapper.FromSilk(registration.TextureFormat);
+        return true;
+    }
+
+    /// <summary>
+    /// Resolves the WebGPU texture format identifier and any required device feature
+    /// for <typeparamref name="TPixel"/>.
+    /// </summary>
+    /// <typeparam name="TPixel">The requested pixel type.</typeparam>
+    /// <param name="formatId">Receives the mapped texture format identifier on success.</param>
+    /// <param name="requiredFeature">
+    /// Receives the device feature required for storage binding, or
+    /// <see cref="FeatureName.Undefined"/> when no special feature is needed.
+    /// </param>
+    /// <returns>
+    /// <see langword="true"/> when the pixel type has a registered GPU format mapping; otherwise <see langword="false"/>.
+    /// </returns>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    internal static bool TryGetCompositeTextureFormat<TPixel>(out WebGPUTextureFormatId formatId, out FeatureName requiredFeature)
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        if (!CompositePixelHandlers.TryGetValue(typeof(TPixel), out CompositePixelRegistration registration))
         {
             formatId = default;
+            requiredFeature = FeatureName.Undefined;
             return false;
         }
 
         formatId = WebGPUTextureFormatMapper.FromSilk(registration.TextureFormat);
+        requiredFeature = registration.RequiredFeature;
         return true;
     }
 

src/ImageSharp.Drawing.WebGPU/WebGPUDrawingBackend.CoverageRasterizer.cs

@@ -10,7 +10,10 @@
 
 namespace SixLabors.ImageSharp.Drawing.Processing.Backends;
 
-internal sealed unsafe partial class WebGPUDrawingBackend
+/// <content>
+/// Coverage rasterization helpers.
+/// </content>
+public sealed unsafe partial class WebGPUDrawingBackend
 {
     private const int TileHeight = 16;
     private const int EdgeStrideBytes = 16;

src/ImageSharp.Drawing.WebGPU/WebGPUDrawingBackend.Readback.cs

@@ -11,7 +11,10 @@
 
 namespace SixLabors.ImageSharp.Drawing.Processing.Backends;
 
-internal sealed unsafe partial class WebGPUDrawingBackend
+/// <content>
+/// GPU readback helpers.
+/// </content>
+public sealed unsafe partial class WebGPUDrawingBackend
 {
     private const int ReadbackCallbackTimeoutMilliseconds = 5000;
 
@@ -46,7 +49,7 @@ public bool TryReadRegion<TPixel>(
             return false;
         }
 
-        if (!TryGetCompositeTextureFormat<TPixel>(out WebGPUTextureFormatId expectedFormat) ||
+        if (!TryGetCompositeTextureFormat<TPixel>(out WebGPUTextureFormatId expectedFormat, out FeatureName requiredFeature) ||
             expectedFormat != capability.TargetFormat)
         {
             return false;
@@ -68,6 +71,13 @@ public bool TryReadRegion<TPixel>(
         using WebGPURuntime.Lease lease = WebGPURuntime.Acquire();
         WebGPU api = lease.Api;
         Device* device = (Device*)capability.Device;
+
+        if (requiredFeature != FeatureName.Undefined
+            && !WebGPUFlushContext.GetOrCreateDeviceState(api, device).HasFeature(requiredFeature))
+        {
+            return false;
+        }
+
         Queue* queue = (Queue*)capability.Queue;
 
         int pixelSizeInBytes = Unsafe.SizeOf<TPixel>();

src/ImageSharp.Drawing.WebGPU/WebGPUDrawingBackend.cs

@@ -32,11 +32,8 @@ namespace SixLabors.ImageSharp.Drawing.Processing.Backends;
 ///   -> Blit once and optionally read back to CPU region
 ///   -> On failure: delegate scene to DefaultDrawingBackend
 /// </code>
-/// <para>
-/// See src/ImageSharp.Drawing.WebGPU/WEBGPU_BACKEND_PROCESS.md for a full process walkthrough.
-/// </para>
 /// </remarks>
-internal sealed unsafe partial class WebGPUDrawingBackend : IDrawingBackend, IDisposable
+public sealed unsafe partial class WebGPUDrawingBackend : IDrawingBackend, IDisposable
 {
     private const int CompositeTileWidth = 16;
     private const int CompositeTileHeight = 16;
@@ -119,29 +116,6 @@ public WebGPUDrawingBackend()
     /// </summary>
     internal int TestingComputePathBatchCount { get; private set; }
 
-    /// <summary>
-    /// Attempts to expose native WebGPU device and queue handles for interop.
-    /// </summary>
-    /// <param name="deviceHandle">Receives the device pointer when available.</param>
-    /// <param name="queueHandle">Receives the queue pointer when available.</param>
-    /// <returns><see langword="true"/> when both handles are available; otherwise <see langword="false"/>.</returns>
-    internal bool TryGetInteropHandles(out nint deviceHandle, out nint queueHandle)
-    {
-        this.ThrowIfDisposed();
-        if (WebGPUFlushContext.TryGetInteropHandles(out deviceHandle, out queueHandle, out string? error))
-        {
-            this.TestingGPUInitializationAttempted = true;
-            this.TestingIsGPUReady = true;
-            this.TestingLastGPUInitializationFailure = null;
-            return true;
-        }
-
-        this.TestingGPUInitializationAttempted = true;
-        this.TestingIsGPUReady = false;
-        this.TestingLastGPUInitializationFailure = error;
-        return false;
-    }
-
     /// <inheritdoc />
     public void FlushCompositions<TPixel>(
         Configuration configuration,
@@ -158,7 +132,7 @@ public void FlushCompositions<TPixel>(
             return;
         }
 
-        if (!TryGetCompositeTextureFormat<TPixel>(out WebGPUTextureFormatId formatId) ||
+        if (!TryGetCompositeTextureFormat<TPixel>(out WebGPUTextureFormatId formatId, out FeatureName requiredFeature) ||
             !AreAllCompositionBrushesSupported<TPixel>(compositionScene.Commands))
         {
             int fallbackCommandCount = compositionScene.Commands.Count;
@@ -232,13 +206,27 @@ public void FlushCompositions<TPixel>(
         string? failure = null;
         int pixelSizeInBytes = Unsafe.SizeOf<TPixel>();
 
-        WebGPUFlushContext flushContext = WebGPUFlushContext.Create(
+        WebGPUFlushContext? flushContext = WebGPUFlushContext.Create(
             target,
             textureFormat,
+            requiredFeature,
             pixelSizeInBytes,
             configuration.MemoryAllocator,
             compositionBounds);
 
+        if (flushContext is null)
+        {
+            this.TestingFallbackPrepareCoverageCallCount += commandCount;
+            this.TestingFallbackCompositeCoverageCallCount += commandCount;
+            this.FlushCompositionsFallback(
+                configuration,
+                target,
+                compositionScene,
+                target.TryGetCpuRegion(out Buffer2DRegion<TPixel> _),
+                compositionBounds);
+            return;
+        }
+
         try
         {
             gpuReady = true;
@@ -253,7 +241,9 @@ public void FlushCompositions<TPixel>(
                 compositionBounds.Value,
                 commandCount,
                 out failure);
+
             bool finalizeOk = renderOk && this.TryFinalizeFlush(flushContext, cpuRegion, compositionBounds);
+
             gpuSuccess = finalizeOk;
         }
         catch (Exception ex)
@@ -345,7 +335,7 @@ private void FlushCompositionsFallback<TPixel>(
             WebGPUFlushContext.RentFallbackStaging<TPixel>(configuration.MemoryAllocator, in targetBounds);
 
         Buffer2DRegion<TPixel> stagingRegion = stagingLease.Region;
-        ICanvasFrame<TPixel> stagingFrame = new CpuCanvasFrame<TPixel>(stagingRegion);
+        ICanvasFrame<TPixel> stagingFrame = new MemoryCanvasFrame<TPixel>(stagingRegion);
         this.fallbackBackend.FlushCompositions(configuration, stagingFrame, compositionScene);
 
         using WebGPUFlushContext uploadContext = WebGPUFlushContext.CreateUploadContext(target, configuration.MemoryAllocator);