add new methods to textbox for line count

include/nana/gui/widgets/skeletons/text_editor.hpp

@@ -183,6 +183,8 @@ namespace nana{	namespace widgets
 
 			void focus_behavior(text_focus_behavior);
 			void select_behavior(bool move_to_end);
+
+			std::size_t line_count(bool text_lines) const;
 		public:
 			void draw_corner();
 			void render(bool focused);

include/nana/gui/widgets/textbox.hpp

@@ -257,6 +257,17 @@ namespace nana
 		 * @param len The length of the queue. If this parameter is zero, the undo/redo is disabled.
 		 */
 		void set_undo_queue_length(std::size_t len);
+
+		/// Returns the number of lines that text are displayed in the screen.
+		/**
+		 * The number of display lines may be not equal to the number of text lines when the textbox
+		 * is line wrapped mode.
+		 * @return the number of lines that text are displayed in the screen.
+		 */
+		std::size_t display_line_count() const;
+
+		/// Returns the number of text lines.
+		std::size_t text_line_count() const;
 	protected:
 		//Overrides widget's virtual functions
 		native_string_type _m_caption() const throw() override;

source/gui/widgets/skeletons/text_editor.cpp

@@ -1872,6 +1872,14 @@ namespace nana{	namespace widgets
 			select_.move_to_end = move_to_end;
 		}
 
+		std::size_t text_editor::line_count(bool text_lines) const
+		{
+			if (text_lines)
+				return textbase().lines();
+
+			return impl_->capacities.behavior->take_lines();
+		}
+
 		void text_editor::draw_corner()
 		{
 			impl_->cview->draw_corner(graph_);

source/gui/widgets/textbox.cpp

@@ -720,6 +720,26 @@ namespace drawerbase {
 				editor->set_undo_queue_length(len);
 		}
 
+		std::size_t textbox::display_line_count() const
+		{
+			internal_scope_guard lock;
+			auto editor = get_drawer_trigger().editor();
+			if (editor)
+				return editor->line_count(false);
+
+			return 0;
+		}
+
+		std::size_t textbox::text_line_count() const
+		{
+			internal_scope_guard lock;
+			auto editor = get_drawer_trigger().editor();
+			if (editor)
+				return editor->line_count(true);
+
+			return 0;
+		}
+
 		//Override _m_caption for caption()
 		auto textbox::_m_caption() const throw() -> native_string_type
 		{