Add settings icon, close window when pressing the close button

include/gui/CustomRendererWidget.hpp

@@ -0,0 +1,25 @@
+#pragma once
+
+#include "Widget.hpp"
+
+#include <functional>
+
+namespace gsr {
+    class CustomRendererWidget : public Widget {
+    public:
+        CustomRendererWidget(mgl::vec2f size);
+        CustomRendererWidget(const CustomRendererWidget&) = delete;
+        CustomRendererWidget& operator=(const CustomRendererWidget&) = delete;
+
+        bool on_event(mgl::Event &event, mgl::Window &window, mgl::vec2f offset) override;
+        void draw(mgl::Window &window, mgl::vec2f offset) override;
+
+        mgl::vec2f get_size() override;
+
+        std::function<void(mgl::Window &window, mgl::vec2f pos, mgl::vec2f size)> draw_handler;
+        // Return true to allow other widgets to handle events
+        std::function<bool(mgl::Event &event, mgl::Window &window, mgl::vec2f pos, mgl::vec2f size)> event_handler;
+    private:
+        mgl::vec2f size;
+    };
+}