Use dark title bar for dark theme on Windows

ApplicationLibCode/UserInterface/RiuMainWindowBase.cpp

@@ -24,14 +24,16 @@
 #include "RiaRegressionTestRunner.h"
 #include "RiaVersionInfo.h"
 
-#include "RiuDockWidgetTools.h"
-#include "RiuDragDrop.h"
-#include "RiuMdiArea.h"
-#include "RiuMdiSubWindow.h"
-
 #include "RimProject.h"
 #include "RimViewWindow.h"
 
+#include "RiuDockWidgetTools.h"
+#include "RiuDragDrop.h"
+#include "RiuGuiTheme.h"
+#include "RiuMainWindowTools.h"
+#include "RiuMdiArea.h"
+#include "RiuMdiSubWindow.h"
+
 #include "cafCmdFeatureManager.h"
 #include "cafPdmObject.h"
 #include "cafPdmUiTreeView.h"
@@ -83,6 +85,13 @@ RiuMainWindowBase::RiuMainWindowBase()
     m_redoAction = new QAction( QIcon( ":/redo.png" ), tr( "Redo" ), this );
     m_redoAction->setShortcut( QKeySequence::Redo );
     connect( m_redoAction, SIGNAL( triggered() ), SLOT( slotRedo() ) );
+
+#ifdef Q_OS_WIN
+    if ( RiaPreferences::current()->guiTheme() == RiaDefines::ThemeEnum::DARK )
+    {
+        RiuMainWindowTools::setDarkTitleBarWindows( this );
+    }
+#endif
 }
 
 //--------------------------------------------------------------------------------------------------

ApplicationLibCode/UserInterface/RiuMainWindowTools.cpp

@@ -39,6 +39,88 @@
 #include <QMdiSubWindow>
 #include <QModelIndex>
 
+// Dark title bar is taken from
+// https://envyen.com/posts/2021-10-24-QT-Windows-Dark-theme/
+
+#ifdef Q_OS_WIN
+#include <Windows.h>
+#include <dwmapi.h>
+#pragma comment( lib, "Dwmapi.lib" )
+
+enum PreferredAppMode
+{
+    Default,
+    AllowDark,
+    ForceDark,
+    ForceLight,
+    Max
+};
+
+enum WINDOWCOMPOSITIONATTRIB
+{
+    WCA_UNDEFINED                     = 0,
+    WCA_NCRENDERING_ENABLED           = 1,
+    WCA_NCRENDERING_POLICY            = 2,
+    WCA_TRANSITIONS_FORCEDISABLED     = 3,
+    WCA_ALLOW_NCPAINT                 = 4,
+    WCA_CAPTION_BUTTON_BOUNDS         = 5,
+    WCA_NONCLIENT_RTL_LAYOUT          = 6,
+    WCA_FORCE_ICONIC_REPRESENTATION   = 7,
+    WCA_EXTENDED_FRAME_BOUNDS         = 8,
+    WCA_HAS_ICONIC_BITMAP             = 9,
+    WCA_THEME_ATTRIBUTES              = 10,
+    WCA_NCRENDERING_EXILED            = 11,
+    WCA_NCADORNMENTINFO               = 12,
+    WCA_EXCLUDED_FROM_LIVEPREVIEW     = 13,
+    WCA_VIDEO_OVERLAY_ACTIVE          = 14,
+    WCA_FORCE_ACTIVEWINDOW_APPEARANCE = 15,
+    WCA_DISALLOW_PEEK                 = 16,
+    WCA_CLOAK                         = 17,
+    WCA_CLOAKED                       = 18,
+    WCA_ACCENT_POLICY                 = 19,
+    WCA_FREEZE_REPRESENTATION         = 20,
+    WCA_EVER_UNCLOAKED                = 21,
+    WCA_VISUAL_OWNER                  = 22,
+    WCA_HOLOGRAPHIC                   = 23,
+    WCA_EXCLUDED_FROM_DDA             = 24,
+    WCA_PASSIVEUPDATEMODE             = 25,
+    WCA_USEDARKMODECOLORS             = 26,
+    WCA_LAST                          = 27
+};
+
+struct WINDOWCOMPOSITIONATTRIBDATA
+{
+    WINDOWCOMPOSITIONATTRIB Attrib;
+    PVOID                   pvData;
+    SIZE_T                  cbData;
+};
+
+using fnAllowDarkModeForWindow        = BOOL( WINAPI* )( HWND hWnd, BOOL allow );
+using fnSetPreferredAppMode           = PreferredAppMode( WINAPI* )( PreferredAppMode appMode );
+using fnSetWindowCompositionAttribute = BOOL( WINAPI* )( HWND hwnd, WINDOWCOMPOSITIONATTRIBDATA* );
+
+static void setDarkTitlebar( HWND hwnd )
+{
+    HMODULE hUxtheme = LoadLibraryExW( L"uxtheme.dll", NULL, LOAD_LIBRARY_SEARCH_SYSTEM32 );
+    if ( !hUxtheme ) return;
+
+    HMODULE hUser32 = GetModuleHandleW( L"user32.dll" );
+    if ( !hUser32 ) return;
+
+    fnAllowDarkModeForWindow AllowDarkModeForWindow =
+        reinterpret_cast<fnAllowDarkModeForWindow>( GetProcAddress( hUxtheme, MAKEINTRESOURCEA( 133 ) ) );
+    fnSetPreferredAppMode SetPreferredAppMode = reinterpret_cast<fnSetPreferredAppMode>( GetProcAddress( hUxtheme, MAKEINTRESOURCEA( 135 ) ) );
+    fnSetWindowCompositionAttribute SetWindowCompositionAttribute =
+        reinterpret_cast<fnSetWindowCompositionAttribute>( GetProcAddress( hUser32, "SetWindowCompositionAttribute" ) );
+
+    SetPreferredAppMode( AllowDark );
+    BOOL dark = TRUE;
+    AllowDarkModeForWindow( hwnd, dark );
+    WINDOWCOMPOSITIONATTRIBDATA data = { WCA_USEDARKMODECOLORS, &dark, sizeof( dark ) };
+    SetWindowCompositionAttribute( hwnd, &data );
+}
+#endif
+
 //--------------------------------------------------------------------------------------------------
 ///
 //--------------------------------------------------------------------------------------------------
@@ -156,3 +238,15 @@ void RiuMainWindowTools::setFixedWindowSizeFor3dViews( RiuMainWindowBase* mainWi
         }
     }
 }
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+void RiuMainWindowTools::setDarkTitleBarWindows( QWidget* widget )
+{
+    if ( !widget ) return;
+
+#ifdef Q_OS_WIN
+    setDarkTitlebar( reinterpret_cast<HWND>( widget->winId() ) );
+#endif
+}

ApplicationLibCode/UserInterface/RiuMainWindowTools.h

@@ -24,7 +24,7 @@ class PdmUiItem;
 } // namespace caf
 
 class RiuMainWindowBase;
-
+class QWidget;
 //--------------------------------------------------------------------------------------------------
 ///
 //--------------------------------------------------------------------------------------------------
@@ -35,4 +35,5 @@ public:
 
     static void setWindowSizeOnWidgetsInMdiWindows( RiuMainWindowBase* mainWindow, int width, int height );
     static void setFixedWindowSizeFor3dViews( RiuMainWindowBase* mainWindow, int width, int height );
+    static void setDarkTitleBarWindows( QWidget* widget );
 };