add support for scrolling the list with mouse wheel by given number of lines

src/menu.h

@@ -52,6 +52,15 @@ namespace NCurses
 			///
 			virtual void GetSelected(std::vector<size_t> &v) const = 0;
 			
+			/// Highlights given position
+			/// @param pos position to be highlighted
+			///
+			virtual void Highlight(size_t pos) = 0;
+			
+			/// @return currently highlighted position
+			///
+			virtual size_t Choice() const = 0;
+			
 			/// @see Menu::Empty()
 			///
 			virtual bool Empty() const = 0;

src/screen.h

@@ -239,13 +239,21 @@ template <typename WindowType> void Screen<WindowType>::Scroll(Where where, cons
 
 template <typename WindowType> void Screen<WindowType>::MouseButtonPressed(MEVENT me)
 {
+	List *list = Config.mouse_list_scroll_whole_page ? 0 : dynamic_cast<List *>(w);
+	
 	if (me.bstate & BUTTON2_PRESSED)
 	{
-		Scroll(wPageDown);
+		if (list)
+			list->Highlight(list->Choice()+Config.lines_scrolled);
+		else
+			Scroll(wPageDown);
 	}
 	else if (me.bstate & BUTTON4_PRESSED)
 	{
-		Scroll(wPageUp);
+		if (list)
+			list->Highlight(list->Choice() > Config.lines_scrolled ? list->Choice()-Config.lines_scrolled : 0);
+		else
+			Scroll(wPageUp);
 	}
 }
 

src/settings.cpp

@@ -315,6 +315,7 @@ void DefaultConfiguration(ncmpcpp_config &conf)
 	conf.allow_physical_directories_deletion = false;
 	conf.ask_before_clearing_main_playlist = false;
 	conf.mouse_support = true;
+	conf.mouse_list_scroll_whole_page = true;
 	conf.new_design = false;
 	conf.visualizer_use_wave = true;
 	conf.browser_sort_by_mtime = false;
@@ -839,6 +840,10 @@ void ReadConfiguration(ncmpcpp_config &conf)
 			{
 				conf.mouse_support = v == "yes";
 			}
+			else if (cl.find("mouse_list_scroll_whole_page") != std::string::npos)
+			{
+				conf.mouse_list_scroll_whole_page = v == "yes";
+			}
 			else if (cl.find("user_interface") != std::string::npos)
 			{
 				conf.new_design = v == "alternative";

src/settings.h

@@ -208,6 +208,7 @@ struct ncmpcpp_config
 	bool allow_physical_directories_deletion;
 	bool ask_before_clearing_main_playlist;
 	bool mouse_support;
+	bool mouse_list_scroll_whole_page;
 	bool new_design;
 	bool visualizer_use_wave;
 	bool browser_sort_by_mtime;