fixed issue 206, added tests

src/Avalonia.Svg.Skia/SvgCustomDrawOperation.cs

@@ -28,25 +28,28 @@ public void Dispose()
 
     public void Render(ImmediateDrawingContext context)
     {
-        if (_svg?.Picture is null)
+        lock (_svg.Locker)
         {
-            return;
+            if (_svg?.Picture is null)
+            {
+                return;
+            }
+
+            var leaseFeature = context.TryGetFeature<ISkiaSharpApiLeaseFeature>();
+            if (leaseFeature is null)
+            {
+                return;
+            }
+            using var lease = leaseFeature.Lease();
+            var canvas = lease?.SkCanvas;
+            if (canvas is null)
+            {
+                return;
+            }
+
+            canvas.Save();
+            canvas.DrawPicture(_svg.Picture);
+            canvas.Restore();
         }
-
-        var leaseFeature = context.TryGetFeature<ISkiaSharpApiLeaseFeature>();
-        if (leaseFeature is null)
-        {
-            return;
-        }
-        using var lease = leaseFeature.Lease();
-        var canvas = lease?.SkCanvas;
-        if (canvas is null)
-        {
-            return;
-        }
-
-        canvas.Save();
-        canvas.DrawPicture(_svg.Picture);
-        canvas.Restore();
     }
 }

src/Svg.Skia/SKSvg.Model.cs

@@ -95,6 +95,8 @@ public static void Draw(SkiaSharp.SKCanvas skCanvas, string path, SkiaModel skia
 
     public virtual SkiaSharp.SKPicture? Picture { get; protected set; }
 
+    public object Locker { get; } = new object();
+
     public SvgParameters? Parameters => _originalParameters;
 
     public SKSvg()
@@ -181,23 +183,26 @@ public SKSvg()
 
     public SkiaSharp.SKPicture? ReLoad(SvgParameters? parameters)
     {
-        if (!CacheOriginalStream)
+        lock (Locker)
         {
-            throw new ArgumentException($"Enable {nameof(CacheOriginalStream)} feature toggle to enable reload feature.");
-        }
+            if (!CacheOriginalStream)
+            {
+                throw new ArgumentException($"Enable {nameof(CacheOriginalStream)} feature toggle to enable reload feature.");
+            }
 
-        Reset();
+            Reset();
 
-        _originalParameters = parameters;
+            _originalParameters = parameters;
 
-        if (_originalStream == null)
-        {
-            return Load(_originalPath, parameters);
-        }
+            if (_originalStream == null)
+            {
+                return Load(_originalPath, parameters);
+            }
 
-        _originalStream.Position = 0;
+            _originalStream.Position = 0;
 
-        return Load(_originalStream, parameters);
+            return Load(_originalStream, parameters);
+        }
     }
 
     public SkiaSharp.SKPicture? FromSvg(string svg)

tests/Avalonia.Svg.Skia.UnitTests/App.axaml

@@ -0,0 +1,7 @@
+<Application xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             x:Class="UITests.App" RequestedThemeVariant="Light">
+  <Application.Styles>
+    <FluentTheme />
+  </Application.Styles>
+</Application>

tests/Avalonia.Svg.Skia.UnitTests/App.axaml.cs

@@ -0,0 +1,25 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.ApplicationLifetimes;
+using Avalonia.Controls.Primitives;
+using Avalonia.Markup.Xaml;
+
+namespace UITests
+{
+	public partial class App : Application
+	{
+		public override void Initialize()
+		{
+			AvaloniaXamlLoader.Load(this);
+		}
+
+		public override void OnFrameworkInitializationCompleted()
+		{
+			if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
+			{
+				desktop.MainWindow = new Window();
+			}
+			base.OnFrameworkInitializationCompleted();
+		}
+	}
+}

tests/Avalonia.Svg.Skia.UnitTests/Avalonia.Svg.Skia.UnitTests.csproj

@@ -14,8 +14,10 @@
   <Import Project="..\..\build\SkiaSharp.Linux.props" />
   <Import Project="..\..\build\HarfBuzzSharp.NativeAssets.Linux.props" />
   <Import Project="..\..\build\Avalonia.props" />
+  <Import Project="..\..\build\Avalonia.Desktop.props" />
   <Import Project="..\..\build\Avalonia.Skia.props" />
-
+  <Import Project="..\..\build\Avalonia.Themes.Fluent.props" />
+
   <ItemGroup>
     <AvaloniaResource Include="Assets\*" />
   </ItemGroup>

tests/Avalonia.Svg.Skia.UnitTests/AvaloniaApp.cs

@@ -0,0 +1,33 @@
+using System;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.ApplicationLifetimes;
+using Avalonia.Threading;
+
+namespace UITests
+{
+	public static class AvaloniaApp
+	{
+		public static void Stop()
+		{
+			var app = GetApp();
+			if (app is IDisposable disposable)
+			{
+				Dispatcher.UIThread.Post(disposable.Dispose);
+			}
+
+			if (app != null)
+				Dispatcher.UIThread.Post(() => app.Shutdown());
+		}
+
+		public static Window? GetMainWindow() => GetApp()?.MainWindow;
+
+		public static IClassicDesktopStyleApplicationLifetime? GetApp() =>
+			(IClassicDesktopStyleApplicationLifetime?)Application.Current?.ApplicationLifetime;
+
+        public static AppBuilder BuildAvaloniaApp() =>
+            AppBuilder
+                .Configure<App>()
+                .UsePlatformDetect();
+	}
+}

tests/Avalonia.Svg.Skia.UnitTests/AvaloniaUiTestFramework.cs

@@ -0,0 +1,112 @@
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Threading;
+using System.Threading.Tasks;
+
+using Avalonia;
+
+using Xunit;
+using Xunit.Abstractions;
+using Xunit.Sdk;
+
+[assembly: TestFramework("UITests.AvaloniaUiTestFramework", "Avalonia.Svg.Skia.UnitTests")]
+[assembly: CollectionBehavior(CollectionBehavior.CollectionPerAssembly, DisableTestParallelization = true, MaxParallelThreads = 1)]
+namespace UITests
+{
+
+	public class AvaloniaUiTestFramework : XunitTestFramework
+	{
+		public AvaloniaUiTestFramework(IMessageSink messageSink)
+			: base(messageSink)
+		{
+		}
+
+		protected override ITestFrameworkExecutor CreateExecutor(AssemblyName assemblyName)
+			=> new Executor(assemblyName, SourceInformationProvider, DiagnosticMessageSink);
+
+		private class Executor : XunitTestFrameworkExecutor
+		{
+			public Executor(
+				AssemblyName assemblyName,
+				ISourceInformationProvider sourceInformationProvider,
+				IMessageSink diagnosticMessageSink)
+				: base(
+					assemblyName,
+					sourceInformationProvider,
+					diagnosticMessageSink)
+			{
+
+			}
+
+			protected override async void RunTestCases(IEnumerable<IXunitTestCase> testCases,
+				IMessageSink executionMessageSink,
+				ITestFrameworkExecutionOptions executionOptions)
+			{
+				executionOptions.SetValue("xunit.execution.DisableParallelization", false);
+				using var assemblyRunner = new Runner(
+					TestAssembly, testCases, DiagnosticMessageSink, executionMessageSink,
+					executionOptions);
+
+				await assemblyRunner.RunAsync();
+			}
+		}
+
+		private class Runner : XunitTestAssemblyRunner
+		{
+			public Runner(
+				ITestAssembly testAssembly,
+				IEnumerable<IXunitTestCase> testCases,
+				IMessageSink diagnosticMessageSink,
+				IMessageSink executionMessageSink,
+				ITestFrameworkExecutionOptions executionOptions)
+				: base(
+					testAssembly,
+					testCases,
+					diagnosticMessageSink,
+					executionMessageSink,
+					executionOptions)
+			{
+
+			}
+
+			public override void Dispose()
+			{
+				AvaloniaApp.Stop();
+
+				base.Dispose();
+			}
+
+			protected override void SetupSyncContext(int maxParallelThreads)
+			{
+				var tcs = new TaskCompletionSource<SynchronizationContext>();
+				var thread = new Thread(() =>
+				{
+					try
+					{
+						//AvaloniaApp.RegisterDependencies();
+
+						AvaloniaApp
+							.BuildAvaloniaApp()
+							.AfterSetup(_ =>
+							{
+								tcs.SetResult(SynchronizationContext.Current!);
+							})
+							.StartWithClassicDesktopLifetime(new string[0]);
+					}
+					catch (Exception e)
+					{
+						tcs.SetException(e);
+					}
+				})
+				{
+					IsBackground = true
+				};
+
+				thread.Start();
+
+				SynchronizationContext.SetSynchronizationContext(tcs.Task.Result);
+			}
+		}
+	}
+}

tests/Avalonia.Svg.Skia.UnitTests/SvgImageReloadTests.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Avalonia.Controls;
+using Avalonia.Media;
+using Avalonia.Media.Imaging;
+using Avalonia.Platform;
+using Avalonia.Threading;
+using Svg.Skia;
+using Xunit;
+
+namespace Avalonia.Svg.Skia.UnitTests;
+
+public class SvgImageReloadTests
+{
+    Image test;
+    private string css = ".Black { fill: #FF0000; }";
+    Window window;
+    [Fact]
+    public async void SvgImage_ReLoad()
+    {
+        SKSvg.CacheOriginalStream = true;
+        var uri = new Uri($"avares://Avalonia.Svg.Skia.UnitTests/Assets/__tiger.svg");
+        var assetLoader = new StandardAssetLoader(); // AvaloniaLocator.Current.GetService<IAssetLoader>()
+
+        var svgFile = assetLoader.Open(uri);
+
+        var svgSource = SvgSource.LoadFromStream(svgFile);
+        var svgImage = new SvgImage() { Source = svgSource };
+
+        test = new Image();
+        test.Source = svgImage;
+
+        window = new Window();
+        window.Content = test;
+        window.Show();
+
+        var timer = new DispatcherTimer();
+        timer.Interval = TimeSpan.FromMilliseconds(10);
+        timer.Tick += Timer_Tick;
+        timer.Start();
+
+        await Task.Delay(10000);
+
+        timer?.Stop();
+        window?.Close();
+    }
+
+
+
+    private void Timer_Tick(object sender, EventArgs e)
+    {
+        var image = (SvgImage)test.Source;
+        (image.CurrentCss, css) = (css, image.CurrentCss);
+        test.InvalidateVisual();
+    }
+}