Match the system caption buttons more closely

Author: FrayxRulez

Telegram/App.xaml

@@ -13,9 +13,6 @@
         <ResourceDictionary>
             <ResourceDictionary.ThemeDictionaries>
                 <ResourceDictionary x:Key="Default">
-                    <SolidColorBrush x:Key="TitleBarButtonBackgroundPointerOver">#19FFFFFF</SolidColorBrush>
-                    <SolidColorBrush x:Key="TitleBarButtonBackgroundPressed">#33FFFFFF</SolidColorBrush>
-
                     <StaticResource x:Key="SettingsItemBorderBrush"
                                     ResourceKey="CardStrokeColorDefaultBrush" />
                     <StaticResource x:Key="SettingsItemBorderBrushPointerOver"
@@ -58,9 +55,6 @@
                     </LinearGradientBrush>
                 </ResourceDictionary>
                 <ResourceDictionary x:Key="Light">
-                    <SolidColorBrush x:Key="TitleBarButtonBackgroundPointerOver">#19000000</SolidColorBrush>
-                    <SolidColorBrush x:Key="TitleBarButtonBackgroundPressed">#33000000</SolidColorBrush>
-
                     <StaticResource x:Key="SettingsItemBorderBrush"
                                     ResourceKey="CardStrokeColorDefaultBrush" />
                     <StaticResource x:Key="SettingsItemBorderBrushPointerOver"

Telegram/Host/IslandWindow.cs

@@ -132,6 +132,12 @@ public static IslandWindow Create(string title, int x, int y, int width, int hei
             window._islandHwnd = window._native.GetWindowHandle();
             window._source.Content = content;
 
+            // A window can open behind another, and the first WM_ACTIVATE would then never come.
+            if (content is WindowPresenter presenter)
+            {
+                presenter.IsActive = Win32.GetActiveWindow() == window._hwnd;
+            }
+
             // XAML creates the thread's CoreWindow with the first island and parents it there.
             // Destroying that window would destroy it, and it cannot be recreated - so it is moved
             // to a window of ours that never closes.

Telegram/Navigation/WindowContext.Uwp.cs

@@ -237,6 +237,12 @@ private void OnClosed(object sender, CoreWindowEventArgs e)
         private void OnActivated(object sender, Windows.UI.Core.WindowActivatedEventArgs e)
         {
             var isActive = e.WindowActivationState != CoreWindowActivationState.Deactivated;
+
+            if (_content != null)
+            {
+                _content.IsActive = isActive;
+            }
+
             Activated?.Invoke(this, new WindowActivatedEventArgs(isActive));
 
             lock (_activeLock)

Telegram/Navigation/WindowContext.Win32.cs

@@ -116,6 +116,11 @@ bool IIslandOwner.CloseRequested()
         /// </summary>
         void IIslandOwner.ActivationChanged(bool active)
         {
+            if (_content != null)
+            {
+                _content.IsActive = active;
+            }
+
             Activated?.Invoke(this, new WindowActivatedEventArgs(active));
 
             lock (_activeLock)

Telegram/Navigation/WindowContext.cs

@@ -160,10 +160,7 @@ public bool IsMaximized
                 {
                     _isMaximized = value;
 
-                    if (MaximizeButton != null)
-                    {
-                        VisualStateManager.GoToState(MaximizeButton, value ? "Maximized" : "Restored", false);
-                    }
+                    ApplyMaximizeGlyph();
                 }
             }
         }
@@ -212,6 +209,11 @@ public void SetCaptionButtonState(CaptionButtons button, bool pressed)
             GoToCaptionButtonState(CloseButton, CaptionButtons.Close);
         }
 
+        /// <summary>
+        /// The window's own caption buttons dim while it is not the active one, the way the shell's
+        /// do. Pushed in by the host: neither the buttons nor the presenter can see activation, and
+        /// on Win32 the pointer is over the drag bar rather than over them.
+        /// </summary>
         private void GoToCaptionButtonState(Button button, CaptionButtons which)
         {
             if (button == null)
@@ -220,10 +222,41 @@ private void GoToCaptionButtonState(Button button, CaptionButtons which)
             }
 
             var state = _hotButton != which
-                ? "Normal"
+                ? _isActive ? "Normal" : "Unfocused"
                 : _hotPressed ? "Pressed" : "PointerOver";
 
-            VisualStateManager.GoToState(button, state, false);
+            // Transitions, so leaving a button fades the way the system's do rather than snapping.
+            VisualStateManager.GoToState(button, state, true);
+        }
+
+        private bool _isActive = true;
+        /// <summary>
+        /// Whether the window is the active one. The system dims its caption glyphs when it is not,
+        /// and nothing about a button's own pointer state says so - the host has to tell us.
+        /// </summary>
+        public bool IsActive
+        {
+            get => _isActive;
+            set
+            {
+                if (_isActive != value)
+                {
+                    _isActive = value;
+
+                    GoToCaptionButtonState(MinimizeButton, CaptionButtons.Minimize);
+                    GoToCaptionButtonState(MaximizeButton, CaptionButtons.Maximize);
+                    GoToCaptionButtonState(CloseButton, CaptionButtons.Close);
+                }
+            }
+        }
+
+        private void ApplyMaximizeGlyph()
+        {
+            if (MaximizeButton != null)
+            {
+                VisualStateManager.GoToState(MaximizeButton,
+                    _isMaximized ? "WindowStateMaximized" : "WindowStateNormal", false);
+            }
         }
 
         protected override void OnApplyTemplate()
@@ -253,10 +286,7 @@ protected override void OnApplyTemplate()
             }
 
             // The window can already be maximized by the time the template arrives.
-            if (MaximizeButton != null && _isMaximized)
-            {
-                VisualStateManager.GoToState(MaximizeButton, "Maximized", false);
-            }
+            ApplyMaximizeGlyph();
 
             ApplyCaptionButtons();