Fix autosizing when DPI changed

native/Avalonia.Native/src/OSX/window.h

@@ -10,6 +10,8 @@ class WindowBaseImpl;
 -(void) setSwRenderedFrame: (AvnFramebuffer* _Nonnull) fb dispose: (IUnknown* _Nonnull) dispose;
 -(void) onClosed;
 -(AvnPixelSize) getPixelSize;
+-(AvnPlatformResizeReason) getResizeReason;
+-(void) setResizeReason:(AvnPlatformResizeReason)reason;
 @end
 
 @interface AutoFitContentView : NSView
@@ -51,4 +53,23 @@ struct IWindowStateChanged
     virtual AvnWindowState WindowState () = 0;
 };
 
+class ResizeScope
+{
+public:
+    ResizeScope(AvnView* _Nonnull view, AvnPlatformResizeReason reason)
+    {
+        _view = view;
+        _restore = [view getResizeReason];
+        [view setResizeReason:reason];
+    }
+
+    ~ResizeScope()
+    {
+        [_view setResizeReason:_restore];
+    }
+private:
+    AvnView* _Nonnull _view;
+    AvnPlatformResizeReason _restore;
+};
+
 #endif /* window_h */

native/Avalonia.Native/src/OSX/window.mm

@@ -277,7 +277,7 @@ virtual HRESULT SetMinMaxSize (AvnSize minSize, AvnSize maxSize) override
         }
     }
 
-    virtual HRESULT Resize(double x, double y) override
+    virtual HRESULT Resize(double x, double y, AvnPlatformResizeReason reason) override
     {
         if(_inResize)
         {
@@ -287,6 +287,7 @@ virtual HRESULT Resize(double x, double y) override
         _inResize = true;
 
         START_COM_CALL;
+        auto resizeBlock = ResizeScope(View, reason);
 
         @autoreleasepool
         {
@@ -317,7 +318,7 @@ virtual HRESULT Resize(double x, double y) override
             {
                 if(!_shown)
                 {
-                    BaseEvents->Resized(AvnSize{x,y});
+                    BaseEvents->Resized(AvnSize{x,y}, reason);
                 }
 
                 [Window setContentSize:NSSize{x, y}];
@@ -1385,6 +1386,7 @@ @implementation AvnView
     bool _lastKeyHandled;
     AvnPixelSize _lastPixelSize;
     NSObject<IRenderTarget>* _renderTarget;
+    AvnPlatformResizeReason _resizeReason;
 }
 
 - (void)onClosed
@@ -1496,7 +1498,8 @@ -(void)setFrameSize:(NSSize)newSize
         _lastPixelSize.Height = (int)fsize.height;
         [self updateRenderTarget];
 
-        _parent->BaseEvents->Resized(AvnSize{newSize.width, newSize.height});
+        auto reason = [self inLiveResize] ? ResizeUser : _resizeReason;
+        _parent->BaseEvents->Resized(AvnSize{newSize.width, newSize.height}, reason);
     }
 }
 
@@ -1995,6 +1998,16 @@ - (void)concludeDragOperation:(nullable id <NSDraggingInfo>)sender
 
 }
 
+- (AvnPlatformResizeReason)getResizeReason
+{
+    return _resizeReason;
+}
+
+- (void)setResizeReason:(AvnPlatformResizeReason)reason
+{
+    _resizeReason = reason;
+}
+
 @end
 
 
@@ -2382,7 +2395,7 @@ virtual NSWindowStyleMask GetStyle() override
         return NSWindowStyleMaskBorderless;
     }
 
-    virtual HRESULT Resize(double x, double y) override
+    virtual HRESULT Resize(double x, double y, AvnPlatformResizeReason reason) override
     {
         START_COM_CALL;
 

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

@@ -67,7 +67,7 @@ public virtual Point GetAvaloniaPointFromEvent(MotionEvent e, int pointerIndex)
 
         public Action<Rect> Paint { get; set; }
 
-        public Action<Size> Resized { get; set; }
+        public Action<Size, PlatformResizeReason> Resized { get; set; }
 
         public Action<double> ScalingChanged { get; set; }
 
@@ -134,7 +134,7 @@ public virtual void Dispose()
 
         protected virtual void OnResized(Size size)
         {
-            Resized?.Invoke(size);
+            Resized?.Invoke(size, PlatformResizeReason.Unspecified);
         }
 
         class ViewImpl : InvalidationAwareSurfaceView, ISurfaceHolderCallback, IInitEditorInfo

src/Avalonia.Controls/ApiCompatBaseline.txt

@@ -33,15 +33,26 @@ MembersMustExist : Member 'public Avalonia.AvaloniaProperty<Avalonia.Media.Stret
 InterfacesShouldHaveSameMembers : Interface member 'public System.EventHandler<Avalonia.Controls.ApplicationLifetimes.ShutdownRequestedEventArgs> Avalonia.Controls.ApplicationLifetimes.IClassicDesktopStyleApplicationLifetime.ShutdownRequested' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Controls.ApplicationLifetimes.IClassicDesktopStyleApplicationLifetime.add_ShutdownRequested(System.EventHandler<Avalonia.Controls.ApplicationLifetimes.ShutdownRequestedEventArgs>)' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Controls.ApplicationLifetimes.IClassicDesktopStyleApplicationLifetime.remove_ShutdownRequested(System.EventHandler<Avalonia.Controls.ApplicationLifetimes.ShutdownRequestedEventArgs>)' is present in the implementation but not in the contract.
+MembersMustExist : Member 'public System.Action<Avalonia.Size> Avalonia.Controls.Embedding.Offscreen.OffscreenTopLevelImplBase.Resized.get()' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public void Avalonia.Controls.Embedding.Offscreen.OffscreenTopLevelImplBase.Resized.set(System.Action<Avalonia.Size>)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public void Avalonia.Controls.Embedding.Offscreen.OffscreenTopLevelImplBase.SetCursor(Avalonia.Platform.IPlatformHandle)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public Avalonia.AvaloniaProperty Avalonia.AvaloniaProperty Avalonia.Controls.Notifications.NotificationCard.CloseOnClickProperty' does not exist in the implementation but it does exist in the contract.
 EnumValuesMustMatch : Enum value 'Avalonia.Platform.ExtendClientAreaChromeHints Avalonia.Platform.ExtendClientAreaChromeHints.Default' is (System.Int32)2 in the implementation but (System.Int32)1 in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public System.Nullable<Avalonia.Size> Avalonia.Platform.ITopLevelImpl.FrameSize' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public System.Nullable<Avalonia.Size> Avalonia.Platform.ITopLevelImpl.FrameSize.get()' is present in the implementation but not in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public System.Action<Avalonia.Size, Avalonia.Platform.PlatformResizeReason> Avalonia.Platform.ITopLevelImpl.Resized.get()' is present in the implementation but not in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public System.Action<Avalonia.Size> Avalonia.Platform.ITopLevelImpl.Resized.get()' is present in the contract but not in the implementation.
+MembersMustExist : Member 'public System.Action<Avalonia.Size> Avalonia.Platform.ITopLevelImpl.Resized.get()' does not exist in the implementation but it does exist in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.ITopLevelImpl.Resized.set(System.Action<Avalonia.Size, Avalonia.Platform.PlatformResizeReason>)' is present in the implementation but not in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.ITopLevelImpl.Resized.set(System.Action<Avalonia.Size>)' is present in the contract but not in the implementation.
+MembersMustExist : Member 'public void Avalonia.Platform.ITopLevelImpl.Resized.set(System.Action<Avalonia.Size>)' does not exist in the implementation but it does exist in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.ITopLevelImpl.SetCursor(Avalonia.Platform.ICursorImpl)' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.ITopLevelImpl.SetCursor(Avalonia.Platform.IPlatformHandle)' is present in the contract but not in the implementation.
 MembersMustExist : Member 'public void Avalonia.Platform.ITopLevelImpl.SetCursor(Avalonia.Platform.IPlatformHandle)' does not exist in the implementation but it does exist in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.IWindowBaseImpl.Show(System.Boolean)' is present in the contract but not in the implementation.
 MembersMustExist : Member 'public void Avalonia.Platform.IWindowBaseImpl.Show(System.Boolean)' does not exist in the implementation but it does exist in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.IWindowBaseImpl.Show(System.Boolean, System.Boolean)' is present in the implementation but not in the contract.
-Total Issues: 45
+InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.IWindowImpl.Resize(Avalonia.Size)' is present in the contract but not in the implementation.
+MembersMustExist : Member 'public void Avalonia.Platform.IWindowImpl.Resize(Avalonia.Size)' does not exist in the implementation but it does exist in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.IWindowImpl.Resize(Avalonia.Size, Avalonia.Platform.PlatformResizeReason)' is present in the implementation but not in the contract.
+Total Issues: 56

src/Avalonia.Controls/Embedding/Offscreen/OffscreenTopLevelImpl.cs

@@ -31,7 +31,7 @@ public Size ClientSize
             set
             {
                 _clientSize = value;
-                Resized?.Invoke(value);
+                Resized?.Invoke(value, PlatformResizeReason.Unspecified);
             }
         }
 
@@ -49,7 +49,7 @@ public double RenderScaling
 
         public Action<RawInputEventArgs> Input { get; set; }
         public Action<Rect> Paint { get; set; }
-        public Action<Size> Resized { get; set; }
+        public Action<Size, PlatformResizeReason> Resized { get; set; }
         public Action<double> ScalingChanged { get; set; }
 
         public Action<WindowTransparencyLevel> TransparencyLevelChanged { get; set; }

src/Avalonia.Controls/Platform/ITopLevelImpl.cs

@@ -3,11 +3,46 @@
 using Avalonia.Controls;
 using Avalonia.Input;
 using Avalonia.Input.Raw;
+using Avalonia.Layout;
 using Avalonia.Rendering;
 using JetBrains.Annotations;
 
 namespace Avalonia.Platform
 {
+    /// <summary>
+    /// Describes the reason for a <see cref="ITopLevelImpl.Resized"/> message.
+    /// </summary>
+    public enum PlatformResizeReason
+    {
+        /// <summary>
+        /// The resize reason is unknown or unspecified.
+        /// </summary>
+        Unspecified,
+
+        /// <summary>
+        /// The resize was due to the user resizing the window, for example by dragging the
+        /// window frame.
+        /// </summary>
+        User,
+
+        /// <summary>
+        /// The resize was initiated by the application, for example by setting one of the sizing-
+        /// related properties on <see cref="Window"/> such as <see cref="Layoutable.Width"/> or
+        /// <see cref="Layoutable.Height"/>.
+        /// </summary>
+        Application,
+
+        /// <summary>
+        /// The resize was initiated by the layout system.
+        /// </summary>
+        Layout,
+
+        /// <summary>
+        /// The resize was due to a change in DPI.
+        /// </summary>
+        DpiChange,
+    }
+
     /// <summary>
     /// Defines a platform-specific top-level window implementation.
     /// </summary>
@@ -57,7 +92,7 @@ public interface ITopLevelImpl : IDisposable
         /// <summary>
         /// Gets or sets a method called when the toplevel is resized.
         /// </summary>
-        Action<Size> Resized { get; set; }
+        Action<Size, PlatformResizeReason> Resized { get; set; }
 
         /// <summary>
         /// Gets or sets a method called when the toplevel's scaling changes.

src/Avalonia.Controls/Platform/IWindowImpl.cs

@@ -110,7 +110,9 @@ public interface IWindowImpl : IWindowBaseImpl
         /// <summary>
         /// Sets the client size of the top level.
         /// </summary>
-        void Resize(Size clientSize);
+        /// <param name="clientSize">The new client size.</param>
+        /// <param name="reason">The reason for the resize.</param>
+        void Resize(Size clientSize, PlatformResizeReason reason = PlatformResizeReason.Application);
 
         /// <summary>
         /// Sets the client size of the top level.

src/Avalonia.Controls/Primitives/PopupRoot.cs

@@ -161,12 +161,9 @@ protected override Size MeasureOverride(Size availableSize)
 
         protected override sealed Size ArrangeSetBounds(Size size)
         {
-            using (BeginAutoSizing())
-            {
-                _positionerParameters.Size = size;
-                UpdatePosition();
-                return ClientSize;
-            }
+            _positionerParameters.Size = size;
+            UpdatePosition();
+            return ClientSize;
         }
     }
 }

src/Avalonia.Controls/TopLevel.cs

@@ -376,11 +376,15 @@ protected virtual void HandleClosed()
             LayoutManager?.Dispose();
         }
 
+        [Obsolete("Use HandleResized(Size, PlatformResizeReason)")]
+        protected virtual void HandleResized(Size clientSize) => HandleResized(clientSize, PlatformResizeReason.Unspecified);
+
         /// <summary>
         /// Handles a resize notification from <see cref="ITopLevelImpl.Resized"/>.
         /// </summary>
         /// <param name="clientSize">The new client size.</param>
-        protected virtual void HandleResized(Size clientSize)
+        /// <param name="reason">The reason for the resize.</param>
+        protected virtual void HandleResized(Size clientSize, PlatformResizeReason reason)
         {
             ClientSize = clientSize;
             FrameSize = PlatformImpl.FrameSize;