gui/osd_helpers.cpp/h: add signal OnAfterChangeResolution

Adds possibility to use any methods after changed resolution without
any changes on COsdHelpers class.
Implementation is possible directly from other objects that need this.


Origin commit data
------------------
Commit: cfdd351ceb
Author: Thilo Graf <dbt@novatux.de>
Date: 2019-04-07 (Sun, 07 Apr 2019)

src/gui/osd_helpers.cpp

@@ -123,6 +123,7 @@ void COsdHelpers::changeOsdResolution(uint32_t mode, bool automode/*=false*/, bo
 			CNeutrinoApp::getInstance()->StartSubtitles();
 		}
 	}
+	OnAfterChangeResolution();
 }
 #else
 void COsdHelpers::changeOsdResolution(uint32_t, bool, bool)

src/gui/osd_helpers.h

@@ -2,12 +2,14 @@
 #ifndef __osd_helpers__
 #define __osd_helpers__
 
+#include <sigc++/signal.h>
+
 enum {
 	OSDMODE_720  = 0,
 	OSDMODE_1080 = 1
 };
 
-class COsdHelpers
+class COsdHelpers : public sigc::trackable
 {
 	private:
 
@@ -23,6 +25,7 @@ class COsdHelpers
 		int  getVideoSystem();
 		uint32_t getOsdResolution();
 		int setVideoSystem(int newSystem, bool remember = true);
+		sigc::signal<void> OnAfterChangeResolution;
 };