Adding an interface for all data in GUI (not useful in this project but can be in another.

include/gui_data_interface.hpp

@@ -0,0 +1,53 @@
+#ifndef BILLYSHEET_GUI_DATA_INTERFACE_HPP
+#define BILLYSHEET_GUI_DATA_INTERFACE_HPP
+
+#include <GLFW/glfw3.h>
+
+namespace gui {
+	class GuiDataInterface {
+	public:
+		GuiDataInterface() noexcept = default;
+
+		virtual ~GuiDataInterface() noexcept = default;
+
+		virtual void key_callback(GLFWwindow *window, int key, int scancode, int action, int mods) = 0;
+
+		virtual void character_callback(GLFWwindow *window, unsigned int codepoint) = 0;
+
+		virtual void cursor_position_callback(GLFWwindow *window, double xpos, double ypos) = 0;
+
+		virtual void cursor_enter_callback(GLFWwindow *window, int entered) = 0;
+
+		virtual void mouse_button_callback(GLFWwindow *window, int button, int action, int mods) = 0;
+
+		virtual void scroll_callback(GLFWwindow *window, double xoffset, double yoffset) = 0;
+
+		virtual void joystick_callback(int jid, int event) = 0;
+
+		virtual void drop_callback(GLFWwindow *window, int count, const char **paths) = 0;
+
+		virtual void window_close_callback(GLFWwindow *window) = 0;
+
+		virtual void window_size_callback(GLFWwindow *window, int width, int height) = 0;
+
+		virtual void framebuffer_size_callback(GLFWwindow *window, int width, int height) = 0;
+
+		virtual void window_content_scale_callback(GLFWwindow *window, float xscale, float yscale) = 0;
+
+		virtual void window_pos_callback(GLFWwindow *window, int xpos, int ypos) = 0;
+
+		virtual void window_iconify_callback(GLFWwindow *window, int iconified) = 0;
+
+		virtual void window_maximize_callback(GLFWwindow *window, int maximized) = 0;
+
+		virtual void window_focus_callback(GLFWwindow *window, int focused) = 0;
+
+		virtual void window_refresh_callback(GLFWwindow *window) = 0;
+
+		virtual void error_callback(int error, const char *message) = 0;
+	};
+
+}
+
+
+#endif //BILLYSHEET_GUI_DATA_INTERFACE_HPP