Is possible Image Stretch Fit Borless?

Someone knows if possible play in window mode, without black area around during gameplay with any core of libretro ???

I really dont like play with black area around the window during gameplay.

you can see some screenshots on my gallery

i try a lots of combinations inside the ~/.config/retroarch/retroarch.cfg .

basically modifying the follow options :

video_force_aspect = "false"
video_fullscreen = "false"
video_windowed_fullscreen = "true"
video_fullscreen_x = "979"
video_fullscreen_y = "818"
video_aspect_ratio_auto = "false"
video_scale_y = "1.000000"
video_scale_x = "1.000000"
video_crop_overscan = "true"
video_scale_integer = "false"
video_aspect_ratio = "0"
aspect_ratio_index = "3"

with

aspect_ratio_index = "3"

with 3 or 11, looks near i wanna but still have a black area (not from game)

But i dont find a method to apply i want. thank you for any help you can give me.