auto& button = window.add<Button>("Plain button")
                     .withCallback([] { cout << "pushed!" << endl; });

/* Create an empty panel with a horizontal layout */
auto& panel = window.add<Widget>()
                    .withLayout<BoxLayout>(BoxLayout::Horizontal, BoxLayout::Middle, 0, 20);

/* Add a slider and set defaults */
auto& slider = panel.add<Slider>()
                    .withValue(0.5f)
                    .withFixedWidth(80);

/* Add a textbox and set defaults */
auto& textBox = panel.add<TextBox>()
                     .withFixedSize(Vector2i(60, 25))
                     .withValue("50")
                     .withUnits("%");

/* Propagate slider changes to the text box */
slider.setCallback([textBox](float value) { textBox.setValue(std::to_string((int) (value * 100))); });


/* Create an empty panel with a horizontal layout */
window.widget()
        .boxlayout(BoxLayout::Horizontal, BoxLayout::Middle, 0, 20))
            /* Add a slider and set defaults */
            .slider(0.5f, [](Slider* obj, float value) {
                if (auto* textBox = obj->gfind<TextBox>("slider-textbox"))
                    textBox->setValue(std::to_string((int) (value * 100)) );
            }).withFixedWidth(80).and() 
            /* Add a textbox and set defaults */   
            .textbox("50", "%").withFixedSize(Vector2i(60, 25))    
   		        .withId("slider-textbox")

/// dvar, bar, strvar, etc. are double/bool/string/.. variables

FormHelper *gui = new FormHelper(screen);
ref<Window> window = gui->addWindow(Eigen::Vector2i(10, 10), "Form helper example");
gui->addGroup("Basic types");
gui->addVariable("bool", bvar);
gui->addVariable("string", strvar);

gui->addGroup("Validating fields");
gui->addVariable("int", ivar);
gui->addVariable("float", fvar);
gui->addVariable("double", dvar);

gui->addGroup("Complex types");
gui->addVariable("Enumeration", enumval, enabled)
   ->setItems({"Item 1", "Item 2", "Item 3"});
gui->addVariable("Color", colval);

gui->addGroup("Other widgets");
gui->addButton("A button", [](){ std::cout << "Button pressed." << std::endl; });

screen->setVisible(true);
screen->performLayout();
window->center();