If that function does what you want on the region then this should do what you want on the entire buffer:
(ansi-color-apply-on-region-int (point-min) (point-max))
If you want to do it interactively then C-x h followed by M-x ansi-color-apply-on-region-int.
Or use this command:
(defun ansi-color-on-buffer ()
I created a package which allows configuring Emacs and many terminal emulators to recognize any combination of key/modifiers (including arrow keys with any combination of Shift/Control/Alt/etc.):