Start building a menu 'class'

menu.cpp

@@ -0,0 +1,30 @@
+#include "menu.h"
+
+bool runSubmenu(Menu_t* current_menu,
+                void(*redraw_callback)(),
+                ButtonPress_e tuner_button,
+                ButtonPress_e touch_button,
+                Point touch_point,
+                int16_t knob){
+  if(nullptr != current_menu->active_submenu){
+    auto ret = current_menu->active_submenu->runMenu(tuner_button,touch_button,touch_point,knob);
+    switch(ret){
+      case MenuReturn_e::StillActive://Fallthrough intended
+      case MenuReturn_e::ExitedNoRedraw:
+      {
+        //Nothing to do here - just return
+        break;
+      }
+      default://Fallthrough intended. Default to this menu being active
+      case MenuReturn_e::ExitedRedraw:
+      {
+        //Turn off submenu, redraw, then return
+        current_menu->active_submenu = nullptr;
+        redraw_callback();
+        break;
+      }
+    }//end switch
+    return true;
+  }//end submenu
+  return false;
+}

menu.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#include <stdint.h>
+#include "nano_gui.h"//Point
+
+enum MenuReturn_e : uint8_t {
+  StillActive,
+  ExitedRedraw,
+  ExitedNoRedraw
+};
+
+enum ButtonPress_e : uint8_t {
+  NotPressed,
+  ShortPress,
+  LongPress
+}
+
+struct Menu_t {
+  MenuReturn_e (*runMenu)(ButtonPress_e tuner_button,
+                          ButtonPress_e touch_button,
+                          Point touch_point,
+                          int16_t knob);
+  Menu_t* active_submenu;
+};
+
+static const uint8_t MENU_KNOB_COUNTS_PER_ITEM = 10;
+
+//Returns true if submenu was run, false otherwise
+bool runSubmenu(Menu_t* current_menu,
+                void(*redraw_callback)(),
+                ButtonPress_e tuner_button,
+                ButtonPress_e touch_button,
+                Point touch_point,
+                int16_t knob);