Add basic common_ui background gfx functions (#415)

* Add basic common_ui background gfx functions

* clang format

* document common_ui.h

* Remove unused tonc header

* Fix header guard name convention

* more header cleanup

* claaaaanggggg format

include/game.h

@@ -1,6 +1,7 @@
 #ifndef GAME_H
 #define GAME_H
 
+#include "game/common_ui.h"
 #include "game_variables.h"
 
 #include <tonc.h>
@@ -38,17 +39,6 @@ typedef struct CardObject CardObject;
 typedef struct Card Card;
 typedef struct JokerObject JokerObject;
 
-enum BackgroundId
-{
-    BG_NONE,
-    BG_CARD_SELECTING,
-    BG_CARD_PLAYING,
-    BG_ROUND_END,
-    BG_SHOP,
-    BG_BLIND_SELECT,
-    BG_MAIN_MENU
-};
-
 // Enum value names in ../include/def_state_info_table.h
 enum GameState
 {
@@ -182,4 +172,9 @@ void set_game_speed(int new_game_speed);
 bool is_shortcut_joker_active(void);
 int get_straight_and_flush_size(void);
 
+// Temporary change for Refactor. Currently this compatibility binder is to allow
+// simultaneous integration of the new system in `common_ui` with the the existing
+// old system incrementally and without losing functionality.
+void change_background_legacy(enum BackgroundId id);
+
 #endif // GAME_H

include/game/common_ui.h

@@ -0,0 +1,30 @@
+/**
+ * @file common_ui.h
+ *
+ * @brief Common functions to render UI elements.
+ */
+#ifndef COMMON_UI_H
+#define COMMON_UI_H
+
+/**
+ * @brief Enum of possible backgrounds to render with @ref change_background
+ */
+enum BackgroundId
+{
+    BG_NONE,
+    BG_CARD_SELECTING,
+    BG_CARD_PLAYING,
+    BG_ROUND_END,
+    BG_SHOP,
+    BG_BLIND_SELECT,
+    BG_MAIN_MENU
+};
+
+/**
+ * Change the background
+ *
+ * @param id @ref BackgroundId to render to screen
+ */
+void change_background(enum BackgroundId id);
+
+#endif // COMMON_UI_H