Apply a GDI region to the top level Island window to allow dragging with a single Xaml Island

src/cascadia/TerminalApp/App.cpp

@@ -99,7 +99,6 @@ namespace winrt::TerminalApp::implementation
         // another for the settings button.
         auto tabsColDef = Controls::ColumnDefinition();
         auto newTabBtnColDef = Controls::ColumnDefinition();
-
         newTabBtnColDef.Width(GridLengthHelper::Auto());
 
         _tabRow.ColumnDefinitions().Append(tabsColDef);
@@ -112,11 +111,9 @@ namespace winrt::TerminalApp::implementation
         _root.RowDefinitions().Append(tabBarRowDef);
         _root.RowDefinitions().Append(Controls::RowDefinition{});
 
-        if (_settings->GlobalSettings().GetShowTabsInTitlebar() == false)
-        {
-            _root.Children().Append(_tabRow);
-            Controls::Grid::SetRow(_tabRow, 0);
-        }
+        _root.Children().Append(_tabRow);
+        Controls::Grid::SetRow(_tabRow, 0);
+
         _root.Children().Append(_tabContent);
         Controls::Grid::SetRow(_tabContent, 1);
         Controls::Grid::SetColumn(_tabView, 0);
@@ -140,6 +137,8 @@ namespace winrt::TerminalApp::implementation
         _CreateNewTabFlyout();
 
         _tabRow.Children().Append(_tabView);
+
+        _newTabButton.Margin({ 0, 0, NON_CLIENT_DRAGBAR_WIDTH, 0 });
         _tabRow.Children().Append(_newTabButton);
 
         _tabContent.VerticalAlignment(VerticalAlignment::Stretch);

src/cascadia/TerminalApp/App.h

@@ -20,6 +20,7 @@
 
 namespace winrt::TerminalApp::implementation
 {
+    const float NON_CLIENT_DRAGBAR_WIDTH = 300.0;
 
     // We dont use AppT as it does not provide access to protected constructors
     template <typename D, typename... I>
@@ -38,6 +39,11 @@ namespace winrt::TerminalApp::implementation
         Windows::Foundation::Point GetLaunchDimensions(uint32_t dpi);
         bool GetShowTabsInTitlebar();
 
+        float GetNonClientAreaDragBarWidth() const noexcept
+        {
+            return NON_CLIENT_DRAGBAR_WIDTH;
+        }
+
         ~App();
 
         hstring GetTitle();

src/cascadia/TerminalApp/App.idl

@@ -29,6 +29,8 @@ namespace TerminalApp
 
         String GetTitle();
 
+        FLOAT GetNonClientAreaDragBarWidth();
+
         // IXamlMetadataProvider, Xaml.Application:
         // Application's composing initializer will register the composing class
         // as the toplevel "active" Xaml application. This Application (through IXamlMetadataProvider)

src/cascadia/WindowsTerminal/AppHost.cpp

@@ -12,27 +12,18 @@ using namespace winrt::Windows::UI::Xaml::Hosting;
 using namespace winrt::Windows::Foundation::Numerics;
 using namespace ::Microsoft::Console::Types;
 
-// The tabs are 34.8px tall. This is their default height - we're not
-// controlling the styling of the tabs at all currently. If we change the size
-// of those, we'll need to change the size here, too. We can't get this size
-// from the tab control until the control is added to a XAML element, and we
-// can't create any XAML elements until we have a window, and we need to know
-// this size before we can create a window, so unfortunately we're stuck
-// hardcoding this.
-const int NON_CLIENT_CONTENT_HEIGHT = static_cast<int>(std::round(34.8));
+double NON_CLIENT_DRAGBAR_WIDTH = 0.0;
 
 AppHost::AppHost() noexcept :
     _app{},
     _window{ nullptr }
 {
     _useNonClientArea = _app.GetShowTabsInTitlebar();
+    NON_CLIENT_DRAGBAR_WIDTH = _app.GetNonClientAreaDragBarWidth();
 
     if (_useNonClientArea)
     {
         _window = std::make_unique<NonClientIslandWindow>();
-        auto pNcWindow = static_cast<NonClientIslandWindow*>(_window.get());
-
-        pNcWindow->SetNonClientHeight(NON_CLIENT_CONTENT_HEIGHT);
     }
     else
     {
@@ -75,11 +66,6 @@ void AppHost::Initialize()
     AppTitleChanged(_app.GetTitle());
 
     _window->SetRootContent(_app.GetRoot());
-    if (_useNonClientArea)
-    {
-        auto pNcWindow = static_cast<NonClientIslandWindow*>(_window.get());
-        pNcWindow->SetNonClientContent(_app.GetTabs());
-    }
 }
 
 // Method Description:

src/cascadia/WindowsTerminal/BaseWindow.h

@@ -163,10 +163,10 @@ class BaseWindow
     ////   https://docs.microsoft.com/en-us/windows/desktop/hidpi/high-dpi-desktop-application-development-on-windows#per-monitor-and-per-monitor-v2-dpi-awareness
     winrt::Windows::Foundation::Size GetLogicalSize(const SIZE physicalSize) const noexcept
     {
-        const auto dpi = GetCurrentDpiScale();
+        const auto scale = GetCurrentDpiScale();
         // 0.5 is to ensure that we pixel snap correctly at the edges, this is necessary with odd DPIs like 1.25, 1.5, 1, .75
-        const auto logicalWidth = (physicalSize.cx / dpi) + 0.5f;
-        const auto logicalHeigth = (physicalSize.cy / dpi) + 0.5f;
+        const auto logicalWidth = (physicalSize.cx / scale) + 0.5f;
+        const auto logicalHeigth = (physicalSize.cy / scale) + 0.5f;
         return winrt::Windows::Foundation::Size(logicalWidth, logicalHeigth);
     }
 

src/cascadia/WindowsTerminal/IslandWindow.h

@@ -22,7 +22,7 @@ class IslandWindow : public BaseWindow<IslandWindow>
     void OnRestore() override;
     void SetRootContent(winrt::Windows::UI::Xaml::UIElement content);
 
-    virtual void Initialize();
+    void Initialize();
 
     void SetCreateCallback(std::function<void(const HWND, const RECT)> pfn) noexcept;