MeterWidgets must move / hide when main window is moved / minimized (#3458)

When the main window is minimized on Linux, the MeterWidgets stay on the desktop.
A signal were added to the main window for state changes.
The VideoWindow connects to that signal and hide/shows the MeterWidgets accordingly.

Currently, when you move the main window, the MeterWidgets do not follow
and become out of place. 
On every Telemetry update, check if the real position on screen of the
video window has changed in order to update the position of the meter
widgets. The Video Window can move for several reasons like when
scrolled or when the Main Window is moved. The Meter Widgets are not
clipped like the Video Window by its scroll area parent though.

src/Gui/MainWindow.cpp

@@ -1037,6 +1037,17 @@ MainWindow::closeEvent(QCloseEvent* event)
     appsettings->setValue(GC_SETTINGS_MAIN_STATE, saveState());
 }
 
+void
+MainWindow::changeEvent(QEvent *event)
+{
+    if(event->type() != QEvent::WindowStateChange) return;
+
+    // Some overlay Widgets (Meter) are top level windows 
+    // and need to follow the MainWindow state
+    Qt::WindowStates states = windowState();
+    emit mainWindowStateChanged(states &  Qt::WindowMinimized, isVisible());
+}
+
 MainWindow::~MainWindow()
 {
     // aside from the tabs, we may need to clean

src/Gui/MainWindow.h

@@ -94,6 +94,9 @@ class MainWindow : public QMainWindow
         // currently selected tab
         Tab *athleteTab() { return currentTab; }
 
+    signals:
+        void mainWindowStateChanged(bool minimized, bool visible);
+
     protected:
 
         // used by ChooseCyclistDialog to see which athletes
@@ -104,6 +107,7 @@ class MainWindow : public QMainWindow
         virtual void resizeEvent(QResizeEvent*);
         virtual void moveEvent(QMoveEvent*);
         virtual void closeEvent(QCloseEvent*);
+        virtual void changeEvent(QEvent *);
         virtual void dragEnterEvent(QDragEnterEvent *);
         virtual void dropEvent(QDropEvent *);
 

src/Train/VideoWindow.cpp

@@ -163,6 +163,7 @@ VideoWindow::VideoWindow(Context *context)  :
         connect(context, SIGNAL(seek(long)), this, SLOT(seekPlayback(long)));
         connect(context, SIGNAL(unpause()), this, SLOT(resumePlayback()));
         connect(context, SIGNAL(mediaSelected(QString)), this, SLOT(mediaSelected(QString)));
+        connect(this->window(), SIGNAL(mainWindowStateChanged(bool, bool)), this, SLOT(mainWindowStateChanged(bool, bool)));
     }
 }
 
@@ -201,6 +202,13 @@ void VideoWindow::resizeEvent(QResizeEvent * )
 {
     foreach(MeterWidget* p_meterWidget , m_metersWidget)
         p_meterWidget->AdjustSizePos();
+    prevPosition = mapToGlobal(pos());
+}
+
+void VideoWindow::mainWindowStateChanged(bool minimized, bool visible)
+{
+    if(minimized) foreach(MeterWidget* p, m_metersWidget) p->hide();
+    else if(visible && isVisible()) foreach(MeterWidget* p, m_metersWidget) p->show();
 }
 
 void VideoWindow::startPlayback()
@@ -246,6 +254,7 @@ void VideoWindow::startPlayback()
         p_meterWidget->raise();
         p_meterWidget->show();
     }
+    prevPosition = mapToGlobal(pos());
 }
 
 void VideoWindow::stopPlayback()
@@ -416,6 +425,10 @@ void VideoWindow::telemetryUpdate(RealtimeData rtd)
         }
     }
 
+    // The Meter Widgets need to follow the Video Window when it moves
+    // (main window moves, scrolling...), we check the position at every update
+    if(mapToGlobal(pos()) != prevPosition) resizeEvent(NULL);
+
     foreach(MeterWidget* p_meterWidget , m_metersWidget)
         p_meterWidget->update();
 

src/Train/VideoWindow.h

@@ -176,6 +176,7 @@ class VideoWindow : public GcChartWindow
         void telemetryUpdate(RealtimeData rtd);
         void seekPlayback(long ms);
         void mediaSelected(QString filename);
+        void mainWindowStateChanged(bool minimized, bool visible);
 
     protected:
 
@@ -192,6 +193,7 @@ class VideoWindow : public GcChartWindow
         bool m_MediaChanged;
 
         QList<MeterWidget*> m_metersWidget;
+        QPoint prevPosition;
 
 #ifdef GC_VIDEO_VLC