feat: Add Win32Properties.WindowCornerHintProperty attached property

AvaloniaUI · Oct 28, 2024 · a996eda · a996eda
1 parent 0944e04
commit a996eda
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Showing 4 changed files with 87 additions and 12 deletions.
diff --git a/src/Avalonia.Controls/Platform/IWin32OptionsTopLevelImpl.cs b/src/Avalonia.Controls/Platform/IWin32OptionsTopLevelImpl.cs
@@ -21,5 +21,10 @@ public interface IWin32OptionsTopLevelImpl : ITopLevelImpl
         /// Gets or sets a custom callback for the window's WndProc
         /// </summary>
         public CustomWndProcHookCallback? WndProcHookCallback { get; set; }
+
+        /// <summary>
+        /// Sets hints that configure the shape of window corners.
+        /// </summary>
+        void SetWindowCornerHints(Win32WindowCornerHints hints);
     }
 }
diff --git a/src/Avalonia.Controls/Platform/Win32CornerHints.cs b/src/Avalonia.Controls/Platform/Win32CornerHints.cs
@@ -0,0 +1,30 @@
+using System;
+
+namespace Avalonia.Platform;
+
+/// <summary>
+/// Specifies hints for window corner appearance.
+/// </summary>
+[Flags]
+public enum Win32WindowCornerHints
+{
+    /// <summary>
+    /// Default Avalonia behavior.
+    /// </summary>
+    NoHint,
+
+    /// <summary>
+    /// The platform's default corner style.
+    /// </summary>
+    PlatformDefault,
+
+    /// <summary>
+    /// Rounded corners for the window.
+    /// </summary>
+    Rounded,
+
+    /// <summary>
+    /// Prevents corners from being rounded.
+    /// </summary>
+    DoNotRound
+}
diff --git a/src/Avalonia.Controls/Platform/Win32Properties.cs b/src/Avalonia.Controls/Platform/Win32Properties.cs
@@ -16,6 +16,12 @@ namespace Avalonia.Controls
     /// </summary>
     public static class Win32Properties
     {
+        public static readonly AttachedProperty<Win32WindowCornerHints> WindowCornerHintProperty =
+            AvaloniaProperty.RegisterAttached<Win32Properties, Window, Win32WindowCornerHints>("WindowCornerHint");
+
+        public static void SetWindowCornerHint(Window obj, Win32WindowCornerHints value) => obj.SetValue(WindowCornerHintProperty, value);
+        public static Win32WindowCornerHints GetWindowCornerHint(Window obj) => obj.GetValue(WindowCornerHintProperty);
+
         public delegate (uint style, uint exStyle) CustomWindowStylesCallback(uint style, uint exStyle);
         public delegate IntPtr CustomWndProcHookCallback(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam, ref bool handled);
 
@@ -70,5 +76,16 @@ public static void RemoveWndProcHookCallback(TopLevel topLevel, CustomWndProcHoo
                 toplevelImpl.WndProcHookCallback -= callback;
             }
         }
+
+        static Win32Properties()
+        {
+            WindowCornerHintProperty.Changed.AddClassHandler<Window>((window, e) =>
+            {
+                if (window.PlatformImpl is IWin32OptionsTopLevelImpl toplevelImpl)
+                {
+                    toplevelImpl.SetWindowCornerHints(e.GetNewValue<Win32WindowCornerHints>());
+                }
+            });
+        }
     }
 }
diff --git a/src/Windows/Avalonia.Win32/WindowImpl.cs b/src/Windows/Avalonia.Win32/WindowImpl.cs
@@ -100,6 +100,7 @@ internal partial class WindowImpl : IWindowImpl, EglGlPlatformSurface.IEglWindow
         private POINT _maxTrackSize;
         private WindowImpl? _parent;
         private ExtendClientAreaChromeHints _extendChromeHints = ExtendClientAreaChromeHints.Default;
+        private Win32WindowCornerHints _cornerHints;
         private bool _isCloseRequested;
         private bool _shown;
         private bool _hiddenWindowIsParent;
@@ -1133,6 +1134,30 @@ private MARGINS UpdateExtendMargins()
             return margins;
         }
 
+        private static DwmWindowCornerPreference HintsToCornerPreference(Win32WindowCornerHints cornerHints, DwmWindowCornerPreference noHintDefault)
+        {
+            return cornerHints switch
+            {
+                Win32WindowCornerHints.NoHint => noHintDefault,
+                Win32WindowCornerHints.PlatformDefault => DwmWindowCornerPreference.DWMWCP_DEFAULT,
+                Win32WindowCornerHints.Rounded => DwmWindowCornerPreference.DWMWCP_ROUND,
+                Win32WindowCornerHints.DoNotRound => DwmWindowCornerPreference.DWMWCP_DONOTROUND,
+                _ => throw new ArgumentOutOfRangeException(nameof(cornerHints), cornerHints, null)
+            };
+        }
+
+        private void UpdateWindowCornerPreference()
+        {
+            int cornerPreference = (int)HintsToCornerPreference(_cornerHints,
+                _isClientAreaExtended && WindowState != WindowState.FullScreen ?
+                    DwmWindowCornerPreference.DWMWCP_ROUND :
+                    DwmWindowCornerPreference.DWMWCP_DEFAULT);
+            unsafe
+            {
+                DwmSetWindowAttribute(_hwnd, (int)DwmWindowAttribute.DWMWA_WINDOW_CORNER_PREFERENCE, &cornerPreference, sizeof(int));
+            }
+        }
+
         private void ExtendClientArea()
         {
             if (!_shown)
@@ -1151,12 +1176,6 @@ private void ExtendClientArea()
             {
                 var margins = UpdateExtendMargins();
                 DwmExtendFrameIntoClientArea(_hwnd, ref margins);
-
-                unsafe
-                {
-                    int cornerPreference = (int)DwmWindowCornerPreference.DWMWCP_ROUND;
-                    DwmSetWindowAttribute(_hwnd, (int)DwmWindowAttribute.DWMWA_WINDOW_CORNER_PREFERENCE, &cornerPreference, sizeof(int));
-                }
             }
             else
             {
@@ -1165,14 +1184,10 @@ private void ExtendClientArea()
 
                 _offScreenMargin = new Thickness();
                 _extendedMargins = new Thickness();
-
-                unsafe
-                {
-                    int cornerPreference = (int)DwmWindowCornerPreference.DWMWCP_DEFAULT;
-                    DwmSetWindowAttribute(_hwnd, (int)DwmWindowAttribute.DWMWA_WINDOW_CORNER_PREFERENCE, &cornerPreference, sizeof(int));
-                }
             }
 
+            UpdateWindowCornerPreference();
+
             if (!_isClientAreaExtended || (_extendChromeHints.HasAllFlags(ExtendClientAreaChromeHints.SystemChrome) &&
                 !_extendChromeHints.HasAllFlags(ExtendClientAreaChromeHints.PreferSystemChrome)))
             {
@@ -1592,6 +1607,14 @@ public void SetExtendClientAreaTitleBarHeightHint(double titleBarHeight)
             ExtendClientArea();
         }
 
+        /// <inheritdoc/>
+        public void SetWindowCornerHints(Win32WindowCornerHints hints)
+        {
+            _cornerHints = hints;
+
+            UpdateWindowCornerPreference();
+        }
+
         /// <inheritdoc/>
         public void GetWindowsZOrder(Span<Window> windows, Span<long> zOrder)
         {