Windows: Add a default setting for hasBorderInFullScreen

The hasBorderInFullScreen only has an effect when set before
the window is shown or switched to fullscreen. This is currently
not possible in the QML case since the window is only accessible
after all properties (including visibility) have been set.
Add a function to set a default value.

[ChangeLog][QtPlatformHeaders][QWindowsWindowFunctions] Add a default
setting for hasBorderInFullScreen

Task-number: QTBUG-47247
Task-number: QTBUG-71855
Change-Id: I3952e3f34bc4eb134cf1c5265b4489fc74112688
Reviewed-by: Andre de la Rocha <andre.rocha@qt.io>
Reviewed-by: Andy Shaw <andy.shaw@qt.io>

src/platformheaders/windowsfunctions/qwindowswindowfunctions.h

@@ -81,6 +81,15 @@ public:
             func(window, border);
     }
 
+    typedef void (*SetHasBorderInFullScreenDefault)(bool border);
+    static const QByteArray setHasBorderInFullScreenDefaultIdentifier() { return QByteArrayLiteral("WindowsSetHasBorderInFullScreenDefault"); }
+    static void setHasBorderInFullScreenDefault(bool border)
+    {
+        auto func = reinterpret_cast<SetHasBorderInFullScreenDefault>(QGuiApplication::platformFunction(setHasBorderInFullScreenDefaultIdentifier()));
+        if (func)
+            func(border);
+    }
+
     typedef void (*SetWindowActivationBehaviorType)(WindowActivationBehavior);
     static const QByteArray setWindowActivationBehaviorIdentifier() { return QByteArrayLiteral("WindowsSetWindowActivationBehavior"); }
 

src/platformheaders/windowsfunctions/qwindowswindowfunctions.qdoc

@@ -93,9 +93,42 @@
     is true then it will enable the WS_BORDER flag in full screen mode to enable other top level windows
     inside the application to appear on top when required.
 
+    \note The setting must be applied before showing the window or switching it
+    to full screen. For QML, setHasBorderInFullScreenDefault() can be used to
+    set a default value.
+
     See also \l [QtDoc] {Fullscreen OpenGL Based Windows}
 */
 
+/*!
+    \typedef QWindowsWindowFunctions::SetHasBorderInFullScreenDefault
+    \since 5.13
+
+    This is the typedef for the function returned by QGuiApplication::platformFunction
+    when passed setHasBorderInFullScreenDefaultIdentifier.
+*/
+
+/*!
+    \fn QByteArray QWindowsWindowFunctions::setHasBorderInFullScreenDefaultIdentifier()
+    \since 5.13
+
+    This function returns the bytearray that can be used to query
+    QGuiApplication::platformFunction to retrieve the SetHasBorderInFullScreen function.
+*/
+
+/*!
+    \fn void QWindowsWindowFunctions::setHasBorderInFullScreenDefault(bool border)
+    \since 5.13
+
+    This is a convenience function that can be used directly instead of resolving
+    the function pointer. \a border will be relayed to the function retrieved by
+    QGuiApplication. When \a border is true, the WS_BORDER flag will be set
+    in full screen mode for all windows by default.
+
+    See also \l [QtDoc] {Fullscreen OpenGL Based Windows}
+    \sa setHasBorderInFullScreen()
+*/
+
 /*!
     \enum QWindowsWindowFunctions::WindowActivationBehavior
 

src/plugins/platforms/windows/qwindowsnativeinterface.cpp

@@ -277,6 +277,8 @@ QFunctionPointer QWindowsNativeInterface::platformFunction(const QByteArray &fun
         return QFunctionPointer(QWindowsWindow::setTouchWindowTouchTypeStatic);
     if (function == QWindowsWindowFunctions::setHasBorderInFullScreenIdentifier())
         return QFunctionPointer(QWindowsWindow::setHasBorderInFullScreenStatic);
+    if (function == QWindowsWindowFunctions::setHasBorderInFullScreenDefaultIdentifier())
+        return QFunctionPointer(QWindowsWindow::setHasBorderInFullScreenDefault);
     if (function == QWindowsWindowFunctions::setWindowActivationBehaviorIdentifier())
         return QFunctionPointer(QWindowsNativeInterface::setWindowActivationBehavior);
     if (function == QWindowsWindowFunctions::isTabletModeIdentifier())

src/plugins/platforms/windows/qwindowswindow.cpp

@@ -1190,6 +1190,7 @@ QWindowCreationContext::QWindowCreationContext(const QWindow *w,
 
 const char *QWindowsWindow::embeddedNativeParentHandleProperty = "_q_embedded_native_parent_handle";
 const char *QWindowsWindow::hasBorderInFullScreenProperty = "_q_has_border_in_fullscreen";
+bool QWindowsWindow::m_borderInFullScreenDefault = false;
 
 QWindowsWindow::QWindowsWindow(QWindow *aWindow, const QWindowsWindowData &data) :
     QWindowsBaseWindow(aWindow),
@@ -1227,7 +1228,7 @@ QWindowsWindow::QWindowsWindow(QWindow *aWindow, const QWindowsWindowData &data)
 
     if (aWindow->isTopLevel())
         setWindowIcon(aWindow->icon());
-    if (aWindow->property(hasBorderInFullScreenProperty).toBool())
+    if (m_borderInFullScreenDefault || aWindow->property(hasBorderInFullScreenProperty).toBool())
         setFlag(HasBorderInFullScreen);
     clearFlag(WithinCreate);
 }
@@ -2804,6 +2805,11 @@ void QWindowsWindow::setHasBorderInFullScreenStatic(QWindow *window, bool border
         window->setProperty(hasBorderInFullScreenProperty, QVariant(border));
 }
 
+void QWindowsWindow::setHasBorderInFullScreenDefault(bool border)
+{
+    m_borderInFullScreenDefault = border;
+}
+
 void QWindowsWindow::setHasBorderInFullScreen(bool border)
 {
     if (testFlag(HasBorderInFullScreen) == border)

src/plugins/platforms/windows/qwindowswindow.h

@@ -338,6 +338,7 @@ public:
     static void setTouchWindowTouchTypeStatic(QWindow *window, QWindowsWindowFunctions::TouchWindowTouchTypes touchTypes);
     void registerTouchWindow(QWindowsWindowFunctions::TouchWindowTouchTypes touchTypes = QWindowsWindowFunctions::NormalTouch);
     static void setHasBorderInFullScreenStatic(QWindow *window, bool border);
+    static void setHasBorderInFullScreenDefault(bool border);
     void setHasBorderInFullScreen(bool border);
     static QString formatWindowTitle(const QString &title);
 
@@ -381,6 +382,7 @@ private:
     // note: intentionally not using void * in order to avoid breaking x86
     VkSurfaceKHR m_vkSurface = 0;
 #endif
+    static bool m_borderInFullScreenDefault;
 };
 
 #ifndef QT_NO_DEBUG_STREAM