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>

1 files changed, 5 insertions, 3 deletions

diff --git a/src/plugins/platforms/xcb/qxcbwindow.h b/src/plugins/platforms/xcb/qxcbwindow.h
index b4d947e700..3e539337b1 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.h
+++ b/src/plugins/platforms/xcb/qxcbwindow.h
@@ -82,7 +82,7 @@ public:
 
     void setVisible(bool visible) override;
     void setWindowFlags(Qt::WindowFlags flags) override;
-    void setWindowState(Qt::WindowState state) override;
+    void setWindowState(Qt::WindowStates state) override;
     WId winId() const override;
     void setParent(const QPlatformWindow *window) override;
 
@@ -243,7 +243,7 @@ protected:
     xcb_sync_int64_t m_syncValue;
     xcb_sync_counter_t m_syncCounter = 0;
 
-    Qt::WindowState m_windowState = Qt::WindowNoState;
+    Qt::WindowStates m_windowState = Qt::WindowNoState;
 
     xcb_gravity_t m_gravity = XCB_GRAVITY_STATIC;
 
@@ -253,6 +253,7 @@ protected:
     bool m_deferredActivation = false;
     bool m_embedded = false;
     bool m_alertState = false;
+    bool m_minimized = false;
     xcb_window_t m_netWmUserTimeWindow = XCB_NONE;
 
     QSurfaceFormat m_format;
@@ -264,7 +265,8 @@ protected:
     QSize m_oldWindowSize;
 
     xcb_visualid_t m_visualId = 0;
-    int m_lastWindowStateEvent = -1;
+    // Last sent state. Initialized to an invalid state, on purpose.
+    Qt::WindowStates m_lastWindowStateEvent = Qt::WindowActive;
 
     enum SyncState {
         NoSyncNeeded,