Added ShowTaskbarIcon implementation

samples/ControlCatalog/MainWindow.xaml.cs

@@ -1,6 +1,7 @@
 using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Markup.Xaml;
+using System;
 
 namespace ControlCatalog
 {
@@ -10,7 +11,8 @@ namespace ControlCatalog
         {
             this.InitializeComponent();
             this.AttachDevTools();
-            Renderer.DrawDirtyRects = Renderer.DrawFps = true;
+            //Renderer.DrawDirtyRects = Renderer.DrawFps = true;
+            PlatformImpl.ShowTaskbarIcon(false);
         }
 
         private void InitializeComponent()

src/Avalonia.Controls/Platform/IWindowImpl.cs

@@ -39,5 +39,9 @@ namespace Avalonia.Platform
         /// Sets the icon of this window.
         /// </summary>
         void SetIcon(IWindowIconImpl icon);
+
+
+
+        void ShowTaskbarIcon(bool value);
     }
 }

src/Gtk/Avalonia.Gtk/WindowImpl.cs

@@ -127,5 +127,10 @@ namespace Avalonia.Gtk
         {
             Window.Icon = ((IconImpl)icon).Pixbuf;
         }
+
+        public void ShowTaskbarIcon(bool value)
+        {
+            Window.SkipTaskbarHint = !value;
+        }
     }
 }

src/Gtk/Avalonia.Gtk3/Interop/Native.cs

@@ -38,6 +38,9 @@ namespace Avalonia.Gtk3.Interop
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
             public delegate void gtk_widget_hide(GtkWidget gtkWidget);
 
+            [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
+            public delegate void gtk_widget_show(GtkWidget gtkWidget);
+
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
             public delegate void gtk_window_set_icon(GtkWindow window, Pixbuf pixbuf);
 
@@ -75,7 +78,6 @@ namespace Avalonia.Gtk3.Interop
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gdk)]
             public delegate void gdk_window_resize(IntPtr gtkWindow, int width, int height);
 
-
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
             public delegate void gtk_widget_realize(GtkWidget gtkWidget);
 
@@ -86,6 +88,13 @@ namespace Avalonia.Gtk3.Interop
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
             public delegate void gtk_window_set_decorated(GtkWindow gtkWindow, bool decorated);
 
+            [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
+            public delegate void gtk_window_set_skip_taskbar_hint(GtkWindow gtkWindow, bool setting); 
+            [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
+            public delegate void gtk_window_set_skip_pager_hint(GtkWindow gtkWindow, bool setting); 
+             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
+            public delegate bool gtk_window_get_skip_taskbar_hint(GtkWindow gtkWindow);
+
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
             public delegate void gtk_window_get_size(GtkWindow gtkWindow, out int width, out int height);
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
@@ -271,6 +280,9 @@ namespace Avalonia.Gtk3.Interop
 
 
         public static D.gtk_window_set_decorated GtkWindowSetDecorated;
+        public static D.gtk_window_set_skip_taskbar_hint GtkWindowSetSkipTaskbarHint;
+        public static D.gtk_window_set_skip_pager_hint GtkWindowSetSkipPagerHint;
+        public static D.gtk_window_get_skip_taskbar_hint GtkWindowGetSkipTaskbarHint;
         public static D.gtk_window_set_title GtkWindowSetTitle;
         public static D.gtk_application_new GtkApplicationNew;
         public static D.gtk_main_iteration GtkMainIteration;
@@ -280,6 +292,7 @@ namespace Avalonia.Gtk3.Interop
         public static D.gtk_init GtkInit;
         public static D.gtk_window_present GtkWindowPresent;
         public static D.gtk_widget_hide GtkWidgetHide;
+        public static D.gtk_widget_show GtkWidgetShow;
         public static D.gdk_get_native_handle GetNativeGdkWindowHandle;
         public static D.gtk_widget_get_window GtkWidgetGetWindow;
         public static D.gtk_widget_get_scale_factor GtkWidgetGetScaleFactor;

src/Gtk/Avalonia.Gtk3/WindowImpl.cs

@@ -2,6 +2,7 @@
 using Avalonia.Controls;
 using Avalonia.Gtk3.Interop;
 using Avalonia.Platform;
+using System.Runtime.InteropServices;
 
 namespace Avalonia.Gtk3
 {
@@ -59,6 +60,11 @@ namespace Avalonia.Gtk3
             //Why do we even have that?
         }
 
+        public void ShowTaskbarIcon(bool value)
+        {
+            Native.GtkWindowSetSkipTaskbarHint(GtkWidget, !value);
+        }
+
         class EmptyDisposable : IDisposable
         {
             public void Dispose()

src/Windows/Avalonia.Win32/WindowImpl.cs

@@ -750,5 +750,22 @@ namespace Avalonia.Win32
 
             return (int)(ptr.ToInt64() & 0xffffffff);
         }
+
+        public void ShowTaskbarIcon(bool value)
+        {
+            var style = (UnmanagedMethods.WindowStyles)UnmanagedMethods.GetWindowLong(_hwnd, -20);
+            
+            style &= ~(UnmanagedMethods.WindowStyles.WS_VISIBLE);   
+
+            style |= UnmanagedMethods.WindowStyles.WS_EX_TOOLWINDOW;   
+            if (value)
+                style |= UnmanagedMethods.WindowStyles.WS_EX_APPWINDOW;
+            else
+                style &= ~(UnmanagedMethods.WindowStyles.WS_EX_APPWINDOW);
+
+            UnmanagedMethods.ShowWindow(_hwnd, ShowWindowCommand.Hide);
+            UnmanagedMethods.SetWindowLong(_hwnd, -20, (uint)style);
+            UnmanagedMethods.ShowWindow(_hwnd, ShowWindowCommand.Show); 
+        }
     }
 }