xcb: Process _NET_WORKAREA and screen geometry changes separately

This commit allows to avoid superfluous calls to the X server.
We don't request _NET_WORKAREA values when the screen geometry changes,
and we avoid RandR calls on each _NET_WORKAREA change.
Besides, update the available geometry of all screens with the
same root window, rather than only that one which corresponds
to Qt::Desktop window.

Change-Id: I5ec624717f5f261c986cd9aaf2425f22985e11c0
Reviewed-by: Błażej Szczygieł <spaz16@wp.pl>
Reviewed-by: Uli Schlachter <psychon@znc.in>
Reviewed-by: Shawn Rutledge <shawn.rutledge@theqtcompany.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/plugins/platforms/xcb/qxcbscreen.h b/src/plugins/platforms/xcb/qxcbscreen.h
index 7b5d3cb30f..c68c290791 100644
--- a/src/plugins/platforms/xcb/qxcbscreen.h
+++ b/src/plugins/platforms/xcb/qxcbscreen.h
@@ -77,10 +77,15 @@ public:
 
     bool compositingActive() const;
 
+    QRect workArea() const { return m_workArea; }
+    void updateWorkArea();
+
     void handleXFixesSelectionNotify(xcb_xfixes_selection_notify_event_t *notify_event);
     void subscribeToXFixesSelectionNotify();
 
 private:
+    QRect getWorkArea() const;
+
     xcb_screen_t *m_screen;
     int m_number;
     QList<QPlatformScreen *> m_screens;
@@ -88,6 +93,8 @@ private:
     QXcbXSettings *m_xSettings;
     xcb_atom_t m_net_wm_cm_atom;
     bool m_compositingActive;
+
+    QRect m_workArea;
 };
 
 class Q_XCB_EXPORT QXcbScreen : public QXcbObject, public QPlatformScreen
@@ -142,6 +149,7 @@ public:
     void handleScreenChange(xcb_randr_screen_change_notify_event_t *change_event);
     void updateGeometry(const QRect &geom, uint8_t rotation);
     void updateGeometry(xcb_timestamp_t timestamp = XCB_TIME_CURRENT_TIME);
+    void updateAvailableGeometry();
     void updateRefreshRate(xcb_randr_mode_t mode);
 
     void readXResources();