modifiable mouse wheel scroll step

source/gui/basis.cpp

@@ -14,21 +14,33 @@
 
 #include <nana/gui/basis.hpp>
 
-namespace nana
+using namespace nana;
+using namespace nana::parameters;
+
+//struct appearance
+appearance::appearance()
+	:taskbar(true), floating(false), no_activate(false),
+	 minimize(true), maximize(true), sizable(true),
+	 decoration(true)
+{}
+
+appearance::appearance(bool has_decorate, bool taskbar, bool is_float, bool no_activate, bool min, bool max, bool sizable)
+	:	taskbar(taskbar), floating(is_float), no_activate(no_activate),
+		minimize(min), maximize(max), sizable(sizable),
+		decoration(has_decorate)
+{}
+//end struct appearance
+
+#if defined(NANA_WINDOWS)
+#	include <windows.h>
+#endif
+
+mouse_wheel::mouse_wheel()
+	: lines(3), characters(3)
 {
-	//struct appearance
-	//@brief: Window appearance structure
-		appearance::appearance()
-			:taskbar(true), floating(false), no_activate(false),
-			 minimize(true), maximize(true), sizable(true),
-			 decoration(true)
-		{}
-
-		appearance::appearance(bool has_decorate, bool taskbar, bool is_float, bool no_activate, bool min, bool max, bool sizable)
-			:	taskbar(taskbar), floating(is_float), no_activate(no_activate),
-				minimize(min), maximize(max), sizable(sizable),
-				decoration(has_decorate)
-		{}
-	//end struct appearance
-}//end namespace nana
+#if defined(NANA_WINDOWS)
+	::SystemParametersInfo(SPI_GETWHEELSCROLLLINES, 0, &lines, 0);
+	::SystemParametersInfo(SPI_GETWHEELSCROLLCHARS, 0, &characters, 0);
+#endif
+}
 

source/gui/widgets/listbox.cpp

@@ -2147,8 +2147,17 @@ namespace nana
 				}
 
 				/// directly set a tested relative display pos
-				void set_scroll_y_dpl(const index_pair& pos_dpl)
+				void set_scroll_y_dpl(index_pair pos_dpl)
 				{
+					if (lister.first() != pos_dpl)
+					{
+						//check the pos_dpl to make sure the last item is at bottom of listbox
+						const auto numbers = this->number_of_lister_items(false);
+						const auto distance = lister.distance(pos_dpl, lister.last());
+						if (numbers > 1 && distance < numbers)
+							lister.backward(lister.last(), numbers - 1, pos_dpl);
+					}
+
 					scroll.offset_y_dpl = pos_dpl;
 					if (pos_dpl.is_category())
 						scroll.offset_y_abs = pos_dpl;
@@ -2161,7 +2170,7 @@ namespace nana
 
 
 				//number_of_lister_item
-				/// @brief  Returns the number of items that are contained in pixels
+				/// @brief  Returns the number of items that are contained on screen.
 				/// @param  with_rest: Means whether including extra one item that is not completely contained in reset pixels.
 				size_type number_of_lister_items(bool with_rest) const
 				{
@@ -2509,11 +2518,11 @@ namespace nana
 					if(scroll.v.empty() || !scroll.v.scrollable(upwards))
 						return false;
 
-					index_pair target;
-					if(upwards == false)
-						lister.forward(scroll.offset_y_dpl, 1, target);
+					index_pair target; //index for display
+					if (upwards == false)
+						lister.forward(scroll.offset_y_dpl, this->scheme_ptr->mouse_wheel.lines, target);
 					else
-						lister.backward(scroll.offset_y_dpl, 1, target);
+						lister.backward(scroll.offset_y_dpl, this->scheme_ptr->mouse_wheel.lines, target);
 
 					if (target == scroll.offset_y_dpl)
 						return false;

source/gui/widgets/skeletons/text_editor.cpp

@@ -2584,7 +2584,7 @@ namespace nana{	namespace widgets
 		{
 			if(vert && attributes_.vscroll)
 			{
-				attributes_.vscroll->make_step(!upwards);
+				attributes_.vscroll->make_step(!upwards, this->scheme_->mouse_wheel.lines);
 				if(_m_scroll_text(true))
 				{
 					render(true);