Make QWindow's windowState a QFlags of the WindowState

This reflects QWidget API, and restores some behavior from Qt4.
Some WM can have several state at the same time. On Plasma for example,
when a window is both maximized and minimized, the "maximized" checkbox
is checked from the taskbar entry.

The API of QPlatformWindow was changed to take a QFlag and the platform
plugins were adapted.

 - On XCB: Always send the full state to the WM. And read the full state.

 - On Windows: The code was originally written with '&' in Qt4, and was changed
   to == when porting. Some adaptation had to be made so the states would be
   preserved.

 - On macOS: Only a single state can be set and is reported back for now,
   with the possibly to expand this in the future.

 - Other platforms: Just do as before with the effective state.

Task-number: QTBUG-57882
Task-number: QTBUG-52616
Task-number: QTBUG-52555
Change-Id: I7a1f7cac64236bbd4c591f796374315639233dad
Reviewed-by: Gunnar Sletta <gunnar@crimson.no>
Reviewed-by: Robin Burchell <robin.burchell@crimson.no>

3 files changed, 12 insertions, 22 deletions

diff --git a/src/plugins/platforms/ios/qiosviewcontroller.mm b/src/plugins/platforms/ios/qiosviewcontroller.mm
index c47b6d68b1..a4c151ed8b 100644
--- a/src/plugins/platforms/ios/qiosviewcontroller.mm
+++ b/src/plugins/platforms/ios/qiosviewcontroller.mm
@@ -176,8 +176,8 @@
         return;
 
     // Re-apply window states to update geometry
-    if (window->windowState() & (Qt::WindowFullScreen | Qt::WindowMaximized))
-        window->handle()->setWindowState(window->windowState());
+    if (window->windowStates() & (Qt::WindowFullScreen | Qt::WindowMaximized))
+        window->handle()->setWindowState(window->windowStates());
 }
 
 // Even if the root view controller has both wantsFullScreenLayout and
diff --git a/src/plugins/platforms/ios/qioswindow.h b/src/plugins/platforms/ios/qioswindow.h
index 81fad420f6..da8a6aabdc 100644
--- a/src/plugins/platforms/ios/qioswindow.h
+++ b/src/plugins/platforms/ios/qioswindow.h
@@ -62,7 +62,7 @@ public:
 
     void setGeometry(const QRect &rect) Q_DECL_OVERRIDE;
 
-    void setWindowState(Qt::WindowState state) Q_DECL_OVERRIDE;
+    void setWindowState(Qt::WindowStates state) Q_DECL_OVERRIDE;
     void setParent(const QPlatformWindow *window) Q_DECL_OVERRIDE;
     void handleContentOrientationChange(Qt::ScreenOrientation orientation) Q_DECL_OVERRIDE;
     void setVisible(bool visible) Q_DECL_OVERRIDE;
diff --git a/src/plugins/platforms/ios/qioswindow.mm b/src/plugins/platforms/ios/qioswindow.mm
index 8ff0dfbd5f..4e6d48423d 100644
--- a/src/plugins/platforms/ios/qioswindow.mm
+++ b/src/plugins/platforms/ios/qioswindow.mm
@@ -73,7 +73,7 @@ QIOSWindow::QIOSWindow(QWindow *window)
     m_normalGeometry = initialGeometry(window, QPlatformWindow::geometry(),
         screen()->availableGeometry().width(), screen()->availableGeometry().height());
 
-    setWindowState(window->windowState());
+    setWindowState(window->windowStates());
     setOpacity(window->opacity());
 
     Qt::ScreenOrientation initialOrientation = window->contentOrientation();
@@ -229,7 +229,7 @@ bool QIOSWindow::isExposed() const
         && window()->isVisible() && !window()->geometry().isEmpty();
 }
 
-void QIOSWindow::setWindowState(Qt::WindowState state)
+void QIOSWindow::setWindowState(Qt::WindowStates state)
 {
     // Update the QWindow representation straight away, so that
     // we can update the statusbar visibility based on the new
@@ -239,25 +239,15 @@ void QIOSWindow::setWindowState(Qt::WindowState state)
     if (window()->isTopLevel() && window()->isVisible() && window()->isActive())
         [m_view.qtViewController updateProperties];
 
-    switch (state) {
-    case Qt::WindowNoState:
-        applyGeometry(m_normalGeometry);
-        break;
-    case Qt::WindowMaximized:
+    if (state & Qt::WindowMinimized)
+        applyGeometry(QRect());
+    else if (state & Qt::WindowFullScreen)
+        applyGeometry(screen()->geometry());
+    else if (state & Qt::WindowMaximized)
         applyGeometry(window()->flags() & Qt::MaximizeUsingFullscreenGeometryHint ?
             screen()->geometry() : screen()->availableGeometry());
-        break;
-    case Qt::WindowFullScreen:
-        applyGeometry(screen()->geometry());
-        break;
-    case Qt::WindowMinimized:
-        applyGeometry(QRect());
-        break;
-    case Qt::WindowActive:
-        Q_UNREACHABLE();
-    default:
-        Q_UNREACHABLE();
-    }
+    else
+        applyGeometry(m_normalGeometry);
 }
 
 void QIOSWindow::setParent(const QPlatformWindow *parentWindow)