Add ui::key_interceptor

libs/ui/include/psemek/ui/key_interceptor.hpp

@@ -0,0 +1,35 @@
+#pragma once
+
+#include <psemek/ui/element.hpp>
+
+#include <functional>
+
+namespace psemek::ui
+{
+
+	struct key_interceptor
+		: element
+	{
+		children_range children() const override { return children_; }
+
+		virtual std::shared_ptr<element> set_child(std::shared_ptr<element> c);
+
+		geom::box<float, 2> size_constraints() const override;
+
+		struct shape const & shape() const override;
+		void reshape(geom::box<float, 2> const & bbox) override;
+
+		void on_key_down(std::function<bool(SDL_Keycode)> callback);
+
+		bool on_event(key_press const & event) override;
+
+		void draw(painter &) const override {}
+
+	private:
+		std::shared_ptr<element> child_;
+		element * children_[1]{nullptr};
+
+		std::function<bool(SDL_Keycode)> callback_;
+	};
+
+}

libs/ui/source/key_interceptor.cpp

@@ -0,0 +1,55 @@
+#include <psemek/ui/key_interceptor.hpp>
+#include <psemek/ui/null_shape.hpp>
+
+namespace psemek::ui
+{
+
+	std::shared_ptr<element> key_interceptor::set_child(std::shared_ptr<element> c)
+	{
+		auto old = std::move(child_);
+		if (old) old->set_parent(nullptr);
+
+		child_ = std::move(c);
+		if (child_) child_->set_parent(this);
+		children_[0] = child_.get();
+
+		return old;
+	}
+
+	geom::box<float, 2> key_interceptor::size_constraints() const
+	{
+		if (child_)
+			return child_->size_constraints();
+		return element::size_constraints();
+	}
+
+	shape const & key_interceptor::shape() const
+	{
+		static const null_shape fallback_shape;
+		if (child_)
+			return child_->shape();
+		return fallback_shape;
+	}
+
+	void key_interceptor::reshape(geom::box<float, 2> const & bbox)
+	{
+		if (child_)
+			child_->reshape(bbox);
+	}
+
+	void key_interceptor::on_key_down(std::function<bool(SDL_Keycode)> callback)
+	{
+		callback_ = std::move(callback);
+	}
+
+	bool key_interceptor::on_event(key_press const & event)
+	{
+		if (callback_ && event.down)
+		{
+			return callback_(event.key);
+		}
+
+		return false;
+	}
+
+}