Added a scroll rate factor.

src/help.cpp

@@ -1607,7 +1607,9 @@ help_text_area::help_text_area(display &disp, const section &toplevel)
 	  title_spacing_(16), curr_loc_(0, 0),
 	  min_row_height_(font::get_max_height(normal_font_size)), curr_row_height_(min_row_height_),
 	  contents_height_(0)
-{}
+{
+	set_scroll_rate(40);
+}
 
 void help_text_area::set_inner_location(SDL_Rect const &rect) {
 	bg_register(rect);

src/widgets/scrollarea.cpp

@@ -101,6 +101,11 @@ void scrollarea::set_full_size(unsigned h)
 	test_scrollbar();
 }
 
+void scrollarea::set_scroll_rate(unsigned r)
+{
+	scrollbar_.set_scroll_rate(r);
+}
+
 void scrollarea::process_event()
 {
 	int grip_position = scrollbar_.get_position();
@@ -131,9 +136,9 @@ void scrollarea::handle_event(const SDL_Event& event)
 	SDL_MouseButtonEvent const &e = event.button;
 	if (point_in_rect(e.x, e.y, inner_location()))
 		if (e.button == SDL_BUTTON_WHEELDOWN)
-			scrollbar_.move_position(1);
+			scrollbar_.move_position(scrollbar_.scroll_rate_);
 		else if (e.button == SDL_BUTTON_WHEELUP)
-			scrollbar_.move_position(-1);
+			scrollbar_.move_position(-scrollbar_.scroll_rate_);
 }
 
 }

src/widgets/scrollarea.hpp

@@ -47,6 +47,7 @@ protected:
 	void move_position(int dep);
 	void set_shown_size(unsigned h);
 	void set_full_size(unsigned h);
+	void set_scroll_rate(unsigned r);
 	bool has_scrollbar() const;
 
 private:

src/widgets/scrollbar.cpp

@@ -40,7 +40,8 @@ scrollbar::scrollbar(display &d)
 	: widget(d), mid_scaled_(NULL), groove_scaled_(NULL),
 	  uparrow_(d, "", button::TYPE_TURBO, "uparrow-button"),
 	  downarrow_(d, "", button::TYPE_TURBO, "downarrow-button"),
-	  state_(NORMAL), grip_position_(0), grip_height_(0), full_height_(0)
+	  state_(NORMAL),
+	  grip_position_(0), grip_height_(0), full_height_(0), scroll_rate_(1)
 {
 	static const surface img(image::get_image(scrollbar_mid, image::UNSCALED));
 	
@@ -124,12 +125,17 @@ void scrollbar::set_full_size(unsigned h)
 	set_dirty(true);
 }
 
+void scrollbar::set_scroll_rate(unsigned r)
+{
+	scroll_rate_ = r;
+}
+
 void scrollbar::process_event()
 {
 	if (uparrow_.pressed())
-		move_position(-1);
+		move_position(-scroll_rate_);
 	if (downarrow_.pressed())
-		move_position(1);
+		move_position(scroll_rate_);
 }
 
 SDL_Rect scrollbar::groove_area() const

src/widgets/scrollbar.hpp

@@ -54,6 +54,9 @@ public:
 	/// Set the relative size of the scrollbar.
 	void set_full_size(unsigned h);
 
+	/// Set scroll rate.
+	void set_scroll_rate(unsigned r);
+
 protected:
 	virtual void update_location(SDL_Rect const &rect);
 	virtual void handle_event(const SDL_Event& event);
@@ -72,7 +75,7 @@ private:
 
 	int minimum_grip_height_, mousey_on_grip_;
 	// Relative data
-	int grip_position_, old_position_, grip_height_, full_height_;
+	int grip_position_, old_position_, grip_height_, full_height_, scroll_rate_;
 
 	friend class scrollarea;
 };

src/widgets/scrollpane.cpp

@@ -36,6 +36,7 @@ scrollpane::scrollpane(display& d) : scrollarea(d), border_(5)
 	content_pos_.x = 0;
 	content_pos_.y = 0;
 	update_content_size();
+	set_scroll_rate(40);
 }
 
 void scrollpane::clear()