Add Japanese Era (Wareki) Display Feature (for Custom LCD) (#57)

watch-faces/complication/wareki_face.h

@@ -0,0 +1,35 @@
+#ifndef WAREKI_FACE_H_
+#define WAREKI_FACE_H_
+
+#include "movement.h"
+
+#define REIWA_LIMIT 2018 + 99
+#define REIWA_GANNEN  2019
+#define HEISEI_GANNEN 1989
+#define SHOWA_GANNEN 1926
+
+typedef struct {
+    bool active;
+    uint32_t disp_year;     //Current displayed year 
+    uint32_t start_year;    //Year when this screen was launched
+    uint32_t real_year;     //The actual current year     
+} wareki_state_t;
+
+void wareki_setup(uint8_t watch_face_index, void ** context_ptr);
+void wareki_activate(void *context);
+bool wareki_loop(movement_event_t event, void *context);
+void wareki_resign(void *context);
+
+void addYear(wareki_state_t* state,int count);
+void subYear(wareki_state_t* state,int count);
+
+#define wareki_face ((const watch_face_t){ \
+    wareki_setup, \
+    wareki_activate, \
+    wareki_loop, \
+    wareki_resign, \
+    NULL, \
+})
+
+#endif // WAREKI_FACE_H_
+