nitpicker: Reduce superfluous refresh operations

repos/os/src/server/nitpicker/chunky_menubar.h

@@ -104,6 +104,8 @@ class Chunky_menubar : public Texture<PT>,
 			           session_label.string(), WHITE, "", session_color);
 		}
 
+		View &view() override { return *this; }
+
 		using Menubar::state;
 };
 

repos/os/src/server/nitpicker/main.cc

@@ -1164,6 +1164,8 @@ void Nitpicker::Main::handle_input(unsigned)
 			framebuffer.refresh(rect.x1(), rect.y1(),
 			                    rect.w(),  rect.h()); });
 
+		user_state.mark_all_views_as_clean();
+
 		/* deliver framebuffer synchronization events */
 		if (!user_state.kill()) {
 			for (::Session *s = session_list.first(); s; s = s->next())

repos/os/src/server/nitpicker/menubar.h

@@ -43,6 +43,8 @@ struct Menubar : Menubar_state
 	virtual void state(Menubar_state) = 0;
 
 	Menubar_state state() const { return *this; }
+
+	virtual View &view() = 0;
 };
 
 #endif

repos/os/src/server/nitpicker/user_state.cc

@@ -41,7 +41,7 @@ User_state::User_state(Global_keys &global_keys, Area view_stack_size, Menubar &
 { }
 
 
-void User_state::_update_all()
+void User_state::_update_menubar()
 {
 	Menubar_state state(*this, "", BLACK);
 
@@ -51,6 +51,14 @@ void User_state::_update_all()
 		                      _input_receiver->color());
 
 	_menubar.state(state);
+
+	refresh_view(_menubar.view(), _menubar.view().abs_geometry());
+}
+
+
+void User_state::_update_all()
+{
+	_update_menubar();
 	update_all_views();
 }
 
@@ -276,5 +284,5 @@ void User_state::focused_session(::Session *session)
 	if (!_global_key_sequence)
 		_input_receiver = session;
 
-	_update_all();
+	_update_menubar();
 }

repos/os/src/server/nitpicker/user_state.h

@@ -59,6 +59,7 @@ class User_state : public Mode, public View_stack
 		 */
 		bool _global_key_sequence = false;
 
+		void _update_menubar();
 		void _update_all();
 
 	public:

repos/os/src/server/nitpicker/view.h

@@ -92,6 +92,7 @@ class View : public Same_buffer_list_elem,
 		Point      _buffer_off;     /* offset to the visible buffer area    */
 		Session   &_session;        /* session that created the view        */
 		char       _title[TITLE_LEN];
+		Dirty_rect _dirty_rect;
 
 		Genode::List<View_parent_elem> _children;
 
@@ -154,7 +155,13 @@ class View : public Same_buffer_list_elem,
 		void remove_child(View const &child) { _children.remove(&child); }
 
 		template <typename FN>
-		void for_each_child(FN const &fn) const {
+		void for_each_child(FN const &fn) {
+			for (View_parent_elem *e = _children.first(); e; e = e->next())
+				fn(*static_cast<View *>(e));
+		}
+
+		template <typename FN>
+		void for_each_const_child(FN const &fn) const {
 			for (View_parent_elem const *e = _children.first(); e; e = e->next())
 				fn(*static_cast<View const *>(e));
 		}
@@ -242,6 +249,23 @@ class View : public Same_buffer_list_elem,
 
 			return true;
 		}
+
+		/**
+		 * Mark part of view as dirty
+		 *
+		 * \param rect  dirty rectangle in absolute coordinates
+		 */
+		void mark_as_dirty(Rect rect) { _dirty_rect.mark_as_dirty(rect); }
+
+		/**
+		 * Return dirty-rectangle information
+		 */
+		Dirty_rect dirty_rect() const { return _dirty_rect; }
+
+		/**
+		 * Reset dirty rectangle
+		 */
+		void mark_as_clean() { _dirty_rect = Dirty_rect(); }
 };
 
 #endif /* _VIEW_H_ */

repos/os/src/server/nitpicker/view_stack.cc

@@ -209,8 +209,9 @@ void View_stack::draw_rec(Canvas_base &canvas, View const *view, Rect rect) cons
 	if (next && left.valid()) draw_rec(canvas, next, left);
 
 	/* draw current view */
-	{
+	view->dirty_rect().flush([&] (Rect const &dirty_rect) {
-		Clip_guard clip_guard(canvas, clipped);
+
+		Clip_guard clip_guard(canvas, Rect::intersect(clipped, dirty_rect));
 
 		/* draw background if view is transparent */
 		if (view->uses_alpha())
@@ -218,7 +219,7 @@ void View_stack::draw_rec(Canvas_base &canvas, View const *view, Rect rect) cons
 
 		view->frame(canvas, _mode);
 		view->draw(canvas, _mode);
-	}
+	});
 
 	/* draw areas at the bottom/right of the current view */
 	if (next &&  right.valid()) draw_rec(canvas, next, right);
@@ -226,14 +227,32 @@ void View_stack::draw_rec(Canvas_base &canvas, View const *view, Rect rect) cons
 }
 
 
-void View_stack::refresh_view(View const &view, Rect const rect)
+void View_stack::refresh_view(View &view, Rect const rect)
 {
-	/* clip argument agains view outline */
+	/* rectangle constrained to view geometry */
-	Rect const intersection = Rect::intersect(rect, _outline(view));
+	Rect const view_rect = Rect::intersect(rect, _outline(view));
 
-	_dirty_rect.mark_as_dirty(intersection);
+	for (View *v = _first_view(); v; v = v->view_stack_next()) {
 
-	view.for_each_child([&] (View const &child) { refresh_view(child, rect); });
+		Rect const intersection = Rect::intersect(view_rect, _outline(*v));
+
+		if (intersection.valid())
+			_mark_view_as_dirty(*v, intersection);
+	}
+
+	view.for_each_child([&] (View &child) { refresh_view(child, rect); });
+}
+
+
+void View_stack::refresh(Rect const rect)
+{
+	for (View *v = _first_view(); v; v = v->view_stack_next()) {
+
+		Rect const intersection = Rect::intersect(rect, _outline(*v));
+
+		if (intersection.valid())
+			refresh_view(*v, intersection);
+	}
 }
 
 
@@ -241,10 +260,19 @@ void View_stack::geometry(View &view, Rect const rect)
 {
 	Rect const old_outline = _outline(view);
 
+	/*
+	 * Refresh area covered by the original view geometry.
+	 *
+	 * We specify the whole geometry to also cover the refresh of child
+	 * views. The 'refresh_view' function takes care to constrain the
+	 * refresh to the actual view geometry.
+	 */
 	refresh_view(view, Rect(Point(), _size));
 
+	/* change geometry */
 	view.geometry(Rect(rect));
 
+	/* refresh new view geometry */
 	refresh_view(view, Rect(Point(), _size));
 
 	Rect const compound = Rect::compound(old_outline, _outline(view));
@@ -263,14 +291,14 @@ void View_stack::buffer_offset(View &view, Point const buffer_off)
 }
 
 
-void View_stack::stack(View const &view, View const *neighbor, bool behind)
+void View_stack::stack(View &view, View const *neighbor, bool behind)
 {
 	_views.remove(&view);
 	_views.insert(&view, _target_stack_position(neighbor, behind));
 
 	_place_labels(view.abs_geometry());
 
-	_dirty_rect.mark_as_dirty(_outline(view));
+	_mark_view_as_dirty(view, _outline(view));
 }
 
 
@@ -279,7 +307,7 @@ void View_stack::title(View &view, const char *title)
 	view.title(title);
 	_place_labels(view.abs_geometry());
 
-	_dirty_rect.mark_as_dirty(_outline(view));
+	_mark_view_as_dirty(view, _outline(view));
 }
 
 
@@ -298,7 +326,7 @@ View *View_stack::find_view(Point p)
 
 void View_stack::remove_view(View const &view, bool redraw)
 {
-	view.for_each_child([&] (View const &child) { remove_view(child); });
+	view.for_each_const_child([&] (View const &child) { remove_view(child); });
 
 	/* remember geometry of view to remove */
 	Rect rect = _outline(view);
@@ -306,5 +334,5 @@ void View_stack::remove_view(View const &view, bool redraw)
 	/* exclude view from view stack */
 	_views.remove(&view);
 
-	_dirty_rect.mark_as_dirty(rect);
+	refresh(rect);
 }

repos/os/src/server/nitpicker/view_stack.h

@@ -76,6 +76,8 @@ class View_stack
 		void _mark_view_as_dirty(View &view, Rect rect)
 		{
 			_dirty_rect.mark_as_dirty(rect);
+
+			view.mark_as_dirty(rect);
 		}
 
 	public:
@@ -96,7 +98,8 @@ class View_stack
 		void size(Area size)
 		{
 			_size = size;
-			_dirty_rect.mark_as_dirty(Rect(Point(0, 0), _size));
+
+			update_all_views();
 		}
 
 		/**
@@ -124,8 +127,23 @@ class View_stack
 		 */
 		void update_all_views()
 		{
-			_place_labels(Rect(Point(), _size));
+			Rect const whole_screen(Point(), _size);
-			_dirty_rect.mark_as_dirty(Rect(Point(), _size));
+
+			_place_labels(whole_screen);
+			_dirty_rect.mark_as_dirty(whole_screen);
+
+			for (View *view = _first_view(); view; view = view->view_stack_next())
+				view->mark_as_dirty(_outline(*view));
+
+		}
+
+		/**
+		 * mark all view-local dirty rectangles a clean
+		 */
+		void mark_all_views_as_clean()
+		{
+			for (View *view = _first_view(); view; view = view->view_stack_next())
+				view->mark_as_clean();
 		}
 
 		/**
@@ -150,7 +168,7 @@ class View_stack
 				                                    rect.p2() + offset),
 				                               view->abs_geometry());
 
-				_mark_view_as_dirty(*view, r);
+				refresh_view(*view, r);
 			}
 		}
 
@@ -159,7 +177,17 @@ class View_stack
 		 *
 		 * \param view  view that should be updated on screen
 		 */
-		void refresh_view(View const &view, Rect);
+		void refresh_view(View &view, Rect);
+
+		/**
+		 * Refresh entire view
+		 */
+		void refresh_view(View &view) { refresh_view(view, _outline(view)); }
+
+		/**
+		 * Refresh area
+		 */
+		void refresh(Rect);
 
 		/**
 		 * Define view geometry
@@ -186,7 +214,7 @@ class View_stack
 		 * bottom of the view stack, specify neighbor = 0 and
 		 * behind = false.
 		 */
-		void stack(View const &view, View const *neighbor = 0, bool behind = true);
+		void stack(View &view, View const *neighbor = 0, bool behind = true);
 
 		/**
 		 * Set view title