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>

2 files changed, 11 insertions, 14 deletions

diff --git a/src/plugins/platforms/haiku/qhaikuwindow.cpp b/src/plugins/platforms/haiku/qhaikuwindow.cpp
index 4634012eda..e19918d7bf 100644
--- a/src/plugins/platforms/haiku/qhaikuwindow.cpp
+++ b/src/plugins/platforms/haiku/qhaikuwindow.cpp
@@ -205,26 +205,23 @@ void QHaikuWindow::requestActivateWindow()
     m_window->Activate(true);
 }
 
-void QHaikuWindow::setWindowState(Qt::WindowState state)
+void QHaikuWindow::setWindowState(Qt::WindowStates state)
 {
     if (m_windowState == state)
         return;
 
-    const Qt::WindowState oldState = m_windowState;
+    const Qt::WindowStates oldState = m_windowState;
 
     m_windowState = state;
 
-    if (m_windowState == Qt::WindowMaximized) {
-        m_window->zoomByQt();
-    } else if (m_windowState == Qt::WindowMinimized) {
+    if (m_windowState & Qt::WindowMinimized)
         m_window->Minimize(true);
-    } else if (m_windowState == Qt::WindowNoState) {
-        if (oldState == Qt::WindowMaximized)
-            m_window->zoomByQt(); // undo zoom
-
-        if (oldState == Qt::WindowMinimized)
-            m_window->Minimize(false); // undo minimize
-    }
+    else if (m_windowState & Qt::WindowMaximized)
+        m_window->zoomByQt();
+    else if (oldState & Qt::WindowMinimized)
+        m_window->Minimize(false); // undo minimize
+    else if (oldState & Qt::WindowMaximized)
+        m_window->zoomByQt(); // undo zoom
 }
 
 void QHaikuWindow::setWindowFlags(Qt::WindowFlags flags)
diff --git a/src/plugins/platforms/haiku/qhaikuwindow.h b/src/plugins/platforms/haiku/qhaikuwindow.h
index 75403fb421..5bfb99e532 100644
--- a/src/plugins/platforms/haiku/qhaikuwindow.h
+++ b/src/plugins/platforms/haiku/qhaikuwindow.h
@@ -94,7 +94,7 @@ public:
     BWindow* nativeHandle() const;
 
     void requestActivateWindow() Q_DECL_OVERRIDE;
-    void setWindowState(Qt::WindowState state) Q_DECL_OVERRIDE;
+    void setWindowState(Qt::WindowStates state) Q_DECL_OVERRIDE;
     void setWindowFlags(Qt::WindowFlags flags) Q_DECL_OVERRIDE;
 
     void setWindowTitle(const QString &title) Q_DECL_OVERRIDE;
@@ -120,7 +120,7 @@ private Q_SLOTS:
     void haikuDrawRequest(const QRect &rect);
 
 private:
-    Qt::WindowState m_windowState;
+    Qt::WindowStates m_windowState;
 };
 
 QT_END_NAMESPACE