Qt, fsc: fix opacity when mouseover

And close #4542
(cherry picked from commit d3c77e33205db2859a6d1f1594ae8efd82e7fd3b)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/qt4/components/controller.cpp

@@ -682,6 +682,7 @@ FullscreenControllerWidget::FullscreenControllerWidget( intf_thread_t *_p_i, QWi
 #if HAVE_TRANSPARENCY
     p_slowHideTimer = new QTimer( this );
     CONNECT( p_slowHideTimer, timeout(), this, slowHideFSC() );
+    f_opacity = var_InheritFloat( p_intf, "qt-fs-opacity" )
 #endif
 
     vlc_mutex_init_recursive( &lock );
@@ -750,7 +751,7 @@ void FullscreenControllerWidget::showFSC()
     }
 
 #if HAVE_TRANSPARENCY
-    setWindowOpacity( var_InheritFloat( p_intf, "qt-fs-opacity" )  );
+    setWindowOpacity( f_opacity );
 #endif
 
 #ifdef Q_WS_X11
@@ -911,7 +912,7 @@ void FullscreenControllerWidget::enterEvent( QEvent *event )
     p_hideTimer->stop();
 #if HAVE_TRANSPARENCY
     p_slowHideTimer->stop();
-    setWindowOpacity( DEFAULT_OPACITY );
+    setWindowOpacity( f_opacity );
 #endif
     event->accept();
 }

modules/gui/qt4/components/controller.hpp

@@ -265,6 +265,7 @@ private:
     QTimer *p_slowHideTimer;
     bool b_slow_hide_begin;
     int  i_slow_hide_timeout;
+    float f_opacity;
 #endif
 
     int i_mouse_last_x, i_mouse_last_y;