Support focused ui elements

libs/ui/include/psemek/ui/element.hpp

@@ -38,6 +38,8 @@ namespace psemek::ui
 		virtual bool on_event(key_press   const &) { return false; }
 		virtual bool on_event(text_input  const &) { return false; }
 
+		virtual bool focused() const { return false; }
+
 		virtual struct shape const & shape() const = 0;
 		virtual void reshape(geom::box<float, 2> const & bbox) = 0;
 		virtual void reshape();

libs/ui/source/controller.cpp

@@ -56,6 +56,7 @@ namespace psemek::ui
 		async::event_loop * loop;
 		painter_impl painter;
 		std::shared_ptr<root_proxy> root;
+		element * focused = nullptr;
 		std::optional<geom::point<int, 2>> mouse;
 		float hint_delay = 0.f;
 		float hint_timer = 0.f;
@@ -66,9 +67,9 @@ namespace psemek::ui
 		impl(async::event_loop * loop);
 
 		template <typename E>
-		bool event(E const & e);
+		element * event(E const & e);
 
-		std::pair<bool, element *> event(mouse_move const & e);
+		element * hinted();
 
 		element * hint() const;
 
@@ -87,49 +88,69 @@ namespace psemek::ui
 	}
 
 	template <typename E>
-	bool controller::impl::event(E const & e)
+	element * controller::impl::event(E const & e)
 	{
-		auto visitor = util::recursive([&](auto && self, element * elem) -> bool {
+		auto visitor = util::recursive([&](auto && self, element * elem) -> element * {
-			if (elem->hidden()) return false;
+			if (elem->hidden()) return nullptr;
 
 			auto cs = elem->children();
 			for (auto it = cs.rbegin(); it != cs.rend(); ++it)
-				if (*it && self(*it)) return true;
+				if (*it)
+					if (auto p = self(*it))
+						return p;
 
-			if (elem->enabled() && elem->on_event(e)) return true;
+			if (elem->enabled() && elem->on_event(e)) return elem;
-			return false;
+			return nullptr;
+		});
+
+		if (focused)
+		{
+			if (focused->focused())
+			{
+				auto result = focused->on_event(e);
+				if (!focused->focused())
+					focused = nullptr;
+				if (result)
+					return focused;
+			}
+			else
+				focused = nullptr;
+		}
+
+		if (root)
+			if (auto result = visitor(root.get()))
+			{
+				if (!focused && result->focused())
+					focused = result;
+			}
+
+		return nullptr;
+	}
+
+	element * controller::impl::hinted()
+	{
+		if (!mouse)
+			return nullptr;
+
+		auto m = geom::cast<float>(*mouse);
+		auto visitor = util::recursive([&](auto && self, element * elem) -> element * {
+			if (elem->hidden()) return nullptr;
+
+			auto cs = elem->children();
+			for (auto it = cs.rbegin(); it != cs.rend(); ++it)
+				if (*it)
+					if (auto p = self(*it))
+						return p;
+
+			if (elem->enabled() && elem->hint() && elem->shape().contains(m))
+				return elem;
+
+			return nullptr;
 		});
 
 		if (root)
 			return visitor(root.get());
-		return false;
+		return nullptr;
-	}
-
-	std::pair<bool, element *> controller::impl::event(mouse_move const & e)
-	{
-		element * hinted = nullptr;
-		auto m = geom::cast<float>(e.position);
-		auto visitor = util::recursive([&](auto && self, element * elem) -> bool {
-			if (elem->hidden()) return false;
-
-			auto cs = elem->children();
-			for (auto it = cs.rbegin(); it != cs.rend(); ++it)
-				if (*it && self(*it)) return true;
-
-			if (elem->enabled())
-			{
-				if (elem->hint() && elem->shape().contains(m) && !hinted)
-					hinted = elem;
-				if (elem->on_event(e))
-					return true;
-			}
-			return false;
-		});
-
-		bool result = false;
-		if (root)
-			result = visitor(root.get());
-		return {result, hinted};
 	}
 
 	void controller::impl::update(float dt)
@@ -194,7 +215,9 @@ namespace psemek::ui
 	bool controller::event(mouse_move const & e)
 	{
 		impl().mouse = e.position;
-		auto [ result, new_hinted_element ] = impl().event(e);
+		auto result = impl().event(e);
+
+		auto new_hinted_element = impl().hinted();
 
 		if (new_hinted_element != impl().hinted_element)
 		{