Non constant declaration
I got an error when compilation. I fix the compilation problem but a proper way to initialize this variable is maybe needed. maybe in lv_init ?
You can fix it and close this pull request.
/**********************
* STATIC VARIABLES
**********************/
-static lv_color_t letter_bg_color = LV_COLOR_WHITE;
+static lv_color_t letter_bg_color;
/**********************
* MACROS
