experiment with sfgui

#include <SFGUI/SFGUI.hpp>
#include <SFGUI/Widgets.hpp>
#include <SFML/Graphics.hpp>

int main()
{
    enum class Option {none, rectangle, circle};
    Option option = Option::none;
    sf::RenderWindow win{sf::VideoMode{400, 400}, "sfgui test"};
    sfg::SFGUI sfgui;
    auto window = sfg::Window::Create();
    window->SetTitle("select option");
    auto box = sfg::Box::Create(sfg::Box::Orientation::VERTICAL);
    auto option1 = sfg::RadioButton::Create("rectangle");
    auto option2 = sfg::RadioButton::Create("circle", option1->GetGroup());
    auto button_select = [&option1, &option2, &option] {
        if (option1->IsActive())
        {
            option = Option::rectangle;
        }
        else if (option2->IsActive())
        {
            option = Option::circle;
        }
    };
    option1->GetSignal(sfg::ToggleButton::OnToggle).Connect(button_select);
    option2->GetSignal(sfg::ToggleButton::OnToggle).Connect(button_select);
    box->Pack(option1);
    box->Pack(option2);
    window->Add(box);
    sf::RectangleShape rect{sf::Vector2f{20, 20}};
    rect.setOrigin(10, 10);
    rect.setPosition(200, 200);
    rect.setFillColor(sf::Color::White);
    while (win.isOpen())
    {
        sf::Event event;
        while (win.pollEvent(event))
        {
            window->HandleEvent(event);
            if (event.type == sf::Event::Closed) win.close();
        }
        window->Update( 0.f );
        win.clear();
        win.resetGLStates();
        sfgui.Display(win);
        win.resetGLStates();
        if (option == Option::rectangle)
        {
            win.draw(rect);
        }
        win.display();
    }
}