gui: initial ctx() support and some simplification
gui: initial ctx() support and some simplification

albertz/music-player,kingsj/music-player,albertz/music-player,albertz/music-player,kingsj/music-player,kingsj/music-player,kingsj/music-player,albertz/music-player,albertz/music-player,kingsj/music-player,albertz/music-player