CScreenSaver: add signal/slot handler OnBeforeStart(), try to fix infoclock

In some constelations it is not required to enable infoclock after close
screensaver. So it is possible to cotrol this from other objects.


Origin commit data
------------------
Commit: 6c8bd66801
Author: Thilo Graf <dbt@novatux.de>
Date: 2015-11-18 (Wed, 18 Nov 2015)

src/gui/screensaver.cpp

@@ -52,7 +52,6 @@ CScreenSaver::CScreenSaver()
 	m_viewer	= new CPictureViewer();
 	index 		= 0;
 	status_mute	= CAudioMute::getInstance()->getStatus();
-	status_clock	= InfoClock->getStatus();
 }
 
 CScreenSaver::~CScreenSaver()
@@ -77,12 +76,10 @@ CScreenSaver* CScreenSaver::getInstance()
 
 void CScreenSaver::Start()
 {
+	OnBeforeStart();
 	status_mute = CAudioMute::getInstance()->getStatus();
 	CAudioMute::getInstance()->enableMuteIcon(false);
 
-	status_clock = InfoClock->getStatus();
-	InfoClock->enableInfoClock(false);
-
 	m_viewer->SetScaling((CPictureViewer::ScalingMode)g_settings.picviewer_scaling);
 	m_viewer->SetVisible(g_settings.screen_StartX, g_settings.screen_EndX, g_settings.screen_StartY, g_settings.screen_EndY);
 
@@ -117,8 +114,12 @@ void CScreenSaver::Stop()
 	thrScreenSaver = 0;
 
 	m_frameBuffer->paintBackground(); //clear entire screen
-	InfoClock->enableInfoClock(status_clock);
+
 	CAudioMute::getInstance()->enableMuteIcon(status_mute);
+	if (!OnAfterStop.empty())
+		OnAfterStop();
+	else
+		InfoClock->enableInfoClock();
 }
 
 void* CScreenSaver::ScreenSaverPrg(void* arg)

src/gui/screensaver.h

@@ -29,7 +29,7 @@
 #include <vector>
 #include <string>
 
-class CScreenSaver
+class CScreenSaver : public sigc::trackable
 {
 	private:
 		CFrameBuffer 	*m_frameBuffer;
@@ -40,7 +40,6 @@ class CScreenSaver
 		unsigned int 	index;
 
 		bool		status_mute;
-		bool		status_clock;
 
 		bool ReadDir();
 		void PaintPicture();
@@ -52,6 +51,8 @@ class CScreenSaver
 
 		void Start();
 		void Stop();
+		sigc::signal<void> OnBeforeStart;
+		sigc::signal<void> OnAfterStop;
 };
 
 #endif // __CSCREENSAVER_H__