Upated (the refactored) the "fill_container()" function to entirely fills the container with no distortion, using scale, center and 'crop' the edges around the container.

Now the function fill_container fullfills the container, centering and cropping the image around the corners, provinding (almost) the same interaction like others zoom functions, eg: fit, with all combination of aspects (horizontal, vertical) of images.
It stills need some work, because i need to fix the fill_container() effect after rotate images and some functions, but the initial goal of the functions stills OK.