Add ui::spawn helper for creating dropdown lists

libs/ui/include/psemek/ui/selector.hpp

@@ -47,4 +47,6 @@ namespace psemek::ui
 		std::function<void(std::size_t)> callback_;
 	};
 
+	bool spawn(element * root, std::shared_ptr<selector> selector, geom::point<int, 2> const & position, std::function<void(std::size_t)> on_selected);
+
 }

libs/ui/source/selector.cpp

@@ -1,4 +1,7 @@
 #include <psemek/ui/selector.hpp>
+#include <psemek/ui/screen.hpp>
+#include <psemek/ui/positioner.hpp>
+#include <psemek/ui/event_interceptor.hpp>
 
 #include <psemek/geom/contains.hpp>
 
@@ -123,5 +126,55 @@ namespace psemek::ui
 		callback_ = std::move(callback);
 	}
 
+	bool spawn(element * root, std::shared_ptr<selector> selector, geom::point<int, 2> const & position, std::function<void(std::size_t)> on_selected)
+	{
+		ui::screen * screen = find_last_parent_of_type<struct screen>(root);
+		if (!screen)
+			return false;
+
+		auto event_interceptor = std::make_shared<struct event_interceptor>();
+		auto positioner = std::make_shared<struct positioner>();
+
+		event_interceptor->set_child(positioner);
+		positioner->set_child(selector);
+
+		auto close = [event_interceptor = event_interceptor.get(), selector = selector.get()]{
+			auto p = dynamic_cast<struct screen *>(event_interceptor->parent());
+			if (p)
+				p->remove_child(event_interceptor);
+
+			selector->on_selected([](std::size_t){});
+		};
+
+		selector->on_selected([close, cb = std::move(on_selected)](std::size_t index){
+			close();
+			cb(index);
+		});
+
+		event_interceptor->on_mouse_click([close](ui::mouse_click const & e) -> bool {
+			if (e.down && (e.button == ui::mouse_button::right || e.button == ui::mouse_button::left))
+			{
+				close();
+				return true;
+			}
+
+			return false;
+		});
+
+		event_interceptor->on_key_press([close](key_press const & e) -> bool {
+			if (e.down && e.key == SDLK_ESCAPE)
+			{
+				close();
+				return true;
+			}
+
+			return false;
+		});
+
+		send_fake_mouse_move_event(event_interceptor.get(), true);
+		positioner->set_position(geom::cast<float>(position), positioner::x_align::left, positioner::y_align::top);
+		screen->add_child(event_interceptor, screen::x_policy::fill, screen::y_policy::fill);
+		return true;
+	}
 
 }