Remove ancient renderer support with Invalidate/Paint calls, drastically simplify InvalidationAwareSurfaceView

src/Android/Avalonia.Android/Platform/SkiaPlatform/InvalidationAwareSurfaceView.cs

@@ -1,30 +1,28 @@
 using System;
 using Android.Content;
 using Android.Graphics;
-using Android.OS;
 using Android.Runtime;
-using Android.Util;
 using Android.Views;
 using Avalonia.Android.Platform.SkiaPlatform;
+using Avalonia.Logging;
 using Avalonia.Platform;
 
 namespace Avalonia.Android
 {
     internal abstract class InvalidationAwareSurfaceView : SurfaceView, ISurfaceHolderCallback, INativePlatformHandleSurface
     {
-        bool _invalidateQueued;
+        private IntPtr _nativeWindowHandle = IntPtr.Zero;
-        private bool _isDisposed;
+        private PixelSize _size = new(1, 1);
-        private bool _isSurfaceValid;
+        private double _scaling = 1;
-        readonly object _lock = new object();
-        private readonly Handler _handler;
 
-        internal event EventHandler? SurfaceWindowCreated;
+        public event EventHandler? SurfaceWindowCreated;
+        public PixelSize Size => _size;
+        public double Scaling => _scaling;
 
-        IntPtr IPlatformHandle.Handle => _isSurfaceValid && Holder?.Surface?.Handle is { } handle ?
+        IntPtr IPlatformHandle.Handle => _nativeWindowHandle;
-            AndroidFramebuffer.ANativeWindow_fromSurface(JNIEnv.Handle, handle) :
+        string IPlatformHandle.HandleDescriptor => "SurfaceView";
-            default;
 
-        public InvalidationAwareSurfaceView(Context context) : base(context)
+        protected InvalidationAwareSurfaceView(Context context) : base(context)
         {
             if (Holder is null)
                 throw new InvalidOperationException(
@@ -32,71 +30,59 @@ namespace Avalonia.Android
 
             Holder.AddCallback(this);
             Holder.SetFormat(global::Android.Graphics.Format.Transparent);
-            _handler = new Handler(context.MainLooper!);
         }
 
-        public override void Invalidate()
+        protected override void Dispose(bool disposing)
         {
-            lock (_lock)
+            ReleaseNativeWindowHandle();
-            {
+            base.Dispose(disposing);
-                if (_invalidateQueued)
-                    return;
-                _handler.Post(() =>
-                {
-                    if (_isDisposed || Holder?.Surface?.IsValid != true)
-                        return;
-                    try
-                    {
-                        DoDraw();
-                    }
-                    catch (Exception e)
-                    {
-                        Log.WriteLine(LogPriority.Error, "Avalonia", e.ToString());
-                    }
-                });
-            }
-        }
-
-        internal new void Dispose()
-        {
-            _isDisposed = true;
         }
 
-        public void SurfaceChanged(ISurfaceHolder holder, Format format, int width, int height)
+        public virtual void SurfaceChanged(ISurfaceHolder holder, Format format, int width, int height)
         {
-            _isSurfaceValid = true;
+            CacheSurfaceProperties(holder);
-            Log.Info("AVALONIA", "Surface Changed");
+            Logger.TryGet(LogEventLevel.Verbose, LogArea.AndroidPlatform)?
-            DoDraw();
+                .Log(this, "InvalidationAwareSurfaceView Changed");
         }
 
         public void SurfaceCreated(ISurfaceHolder holder)
         {
-            _isSurfaceValid = true;
+            CacheSurfaceProperties(holder);
-            Log.Info("AVALONIA", "Surface Created");
+            Logger.TryGet(LogEventLevel.Verbose, LogArea.AndroidPlatform)?
+                .Log(this, "InvalidationAwareSurfaceView Created");
             SurfaceWindowCreated?.Invoke(this, EventArgs.Empty);
-            DoDraw();
         }
 
         public void SurfaceDestroyed(ISurfaceHolder holder)
         {
-            _isSurfaceValid = false;
+            ReleaseNativeWindowHandle();
-            Log.Info("AVALONIA", "Surface Destroyed");
+            _size = new PixelSize(1, 1);
+            _scaling = 1;
+            Logger.TryGet(LogEventLevel.Verbose, LogArea.AndroidPlatform)?
+                .Log(this, "InvalidationAwareSurfaceView Destroyed");
+        }
+
+        private void CacheSurfaceProperties(ISurfaceHolder holder)
+        {
+            ReleaseNativeWindowHandle();
+            var surface = holder?.Surface;
+            if (surface?.Handle is { } handle)
+                _nativeWindowHandle = AndroidFramebuffer.ANativeWindow_fromSurface(JNIEnv.Handle, handle);
+            else
+                _nativeWindowHandle = IntPtr.Zero;
 
+            var frame = holder?.SurfaceFrame;
+            _size = frame != null ? new PixelSize(frame.Width(), frame.Height()) : new PixelSize(1, 1);
+            _scaling = Resources?.DisplayMetrics?.Density ?? 1;
         }
 
-        protected void DoDraw()
+        private void ReleaseNativeWindowHandle()
         {
-            lock (_lock)
+            if (_nativeWindowHandle != IntPtr.Zero)
             {
-                _invalidateQueued = false;
+                AndroidFramebuffer.ANativeWindow_release(_nativeWindowHandle);
+                _nativeWindowHandle = IntPtr.Zero;
             }
-            Draw();
         }
-        protected abstract void Draw();
-        public string HandleDescriptor => "SurfaceView";
-
-        public PixelSize Size => new(Holder?.SurfaceFrame?.Width() ?? 1, Holder?.SurfaceFrame?.Height() ?? 1);
-
-        public double Scaling => Resources?.DisplayMetrics?.Density ?? 1;
     }
 }

src/Android/Avalonia.Android/Platform/SkiaPlatform/TopLevelImpl.cs

@@ -124,11 +124,6 @@ namespace Avalonia.Android.Platform.SkiaPlatform
             InputRoot = inputRoot;
         }
 
-        void Draw()
-        {
-            Paint?.Invoke(new Rect(new Point(0, 0), ClientSize));
-        }
-
         public virtual void Dispose()
         {
             _systemNavigationManager.Dispose();
@@ -146,10 +141,11 @@ namespace Avalonia.Android.Platform.SkiaPlatform
             Resized?.Invoke(size, WindowResizeReason.Layout);
         }
 
-        class ViewImpl : InvalidationAwareSurfaceView, ISurfaceHolderCallback, IInitEditorInfo
+        sealed class ViewImpl : InvalidationAwareSurfaceView, IInitEditorInfo
         {
             private readonly TopLevelImpl _tl;
             private Size _oldSize;
+            private double _oldScaling;
 
             public ViewImpl(Context context, TopLevelImpl tl, bool placeOnTop) : base(context)
             {
@@ -158,13 +154,6 @@ namespace Avalonia.Android.Platform.SkiaPlatform
                     SetZOrderOnTop(true);
             }
 
-            public TopLevelImpl TopLevelImpl => _tl;
-
-            protected override void Draw()
-            {
-                _tl.Draw();
-            }
-
             protected override void DispatchDraw(global::Android.Graphics.Canvas canvas)
             {
                 // Workaround issue #9230 on where screen remains gray after splash screen.
@@ -211,17 +200,24 @@ namespace Avalonia.Android.Platform.SkiaPlatform
                 return res ?? baseResult;
             }
 
-            void ISurfaceHolderCallback.SurfaceChanged(ISurfaceHolder holder, Format format, int width, int height)
+            public override void SurfaceChanged(ISurfaceHolder holder, Format format, int width, int height)
             {
-                var newSize = new PixelSize(width, height).ToSize(_tl.RenderScaling);
+                base.SurfaceChanged(holder, format, width, height);
+
+                var newSize = Size.ToSize(Scaling);
+                var newScaling = Scaling;
 
                 if (newSize != _oldSize)
                 {
                     _oldSize = newSize;
                     _tl.OnResized(newSize);
                 }
-
+                // ReSharper disable once CompareOfFloatsByEqualityOperator
-                base.SurfaceChanged(holder, format, width, height);
+                if (newScaling != _oldScaling)
+                {
+                    _oldScaling =  newScaling;
+                    _tl.ScalingChanged?.Invoke(newScaling);
+                }
             }
 
             public sealed override bool OnCheckIsTextEditor()
@@ -236,11 +232,10 @@ namespace Avalonia.Android.Platform.SkiaPlatform
                 _initEditorInfo = init;
             }
 
-            public sealed override IInputConnection OnCreateInputConnection(EditorInfo? outAttrs)
+            public override IInputConnection OnCreateInputConnection(EditorInfo? outAttrs)
             {
                 return _initEditorInfo?.Invoke(_tl, outAttrs!)!;
             }
-
         }
 
         public IPopupImpl? CreatePopup() => null;
@@ -280,10 +275,8 @@ namespace Avalonia.Android.Platform.SkiaPlatform
 
         IntPtr EglGlPlatformSurface.IEglWindowGlPlatformSurfaceInfo.Handle => ((IPlatformHandle)_view).Handle;
         bool EglGlPlatformSurface.IEglWindowGlPlatformSurfaceInfoWithWaitPolicy.SkipWaits => true;
-
+        PixelSize EglGlPlatformSurface.IEglWindowGlPlatformSurfaceInfo.Size => _view.Size;
-        public PixelSize Size => _view.Size;
+        double EglGlPlatformSurface.IEglWindowGlPlatformSurfaceInfo.Scaling => _view.Scaling;
-
-        public double Scaling => RenderScaling;
 
         public void SetTransparencyLevelHint(IReadOnlyList<WindowTransparencyLevel> transparencyLevels)
         {