.emacs

(defvar anything-show-completion-height-percent 50
  "Maximum percentage of display height that will be preserved when this
`anything-display-function' splits the window.")

(defvar asc-scroll 0
  "Hold the state of the scrolled-upped value.")
(defun asc-scroll-display-function (buf)
  (save-excursion
    (setq asc-scroll 0)
    (asc-scroll-up-maybe)
    (let ((split-window-keep-point)
          (hsize (1+ (count-screen-lines (window-start) (point)))))
      (split-window-vertically (max hsize window-min-height))
      (other-window 1)
      (switch-to-buffer buf))))
(defun asc-scroll-up-maybe ()
  (let* ((lc (count-screen-lines (window-start) (point)))
         (v (truncate (/ (* 100 lc) (window-height)))))
    (when (< anything-show-completion-height-percent v)
      (let ((up (- lc
                   (truncate
                    (* (window-height)
                       (/ anything-show-completion-height-percent 100.0))))))
        (setq asc-scroll up)
        (scroll-up up)))))

;; Entry point for an experiment.
(defun use-anything-show-completeion* (function prefix-length-sexp display-function &rest body)
  (eval
   `(progn
      (ad-disable-advice ',function
                         'around
                         'anything-show-completion)
      (ad-deactivate ',function)
      (defadvice ,function (around anything-show-completion activate)
        (anything-show-completion-install ',prefix-length-sexp)
        (let ((anything-display-function ',display-function))
          ad-do-it))

      ,@body)))

(apply 'use-anything-show-completeion*
       '(anything-complete
         (length anything-complete-target)
         asc-scroll-display-function
         (defadvice anything-complete (after scroll-up activate)
           (when (not (zerop asc-scroll))
             (scroll-up asc-scroll)))))

;; For anything-zsh-screen :)
(defun asc-scroll-up0 (up)
  (cond ((eq major-mode 'term-mode)
         (term-send-raw-string "\033q")
         (term-send-raw-string (format " print -n \"\\033[%dA\"\n"
                                       (1+ up))))
        (t (scroll-up up))))
(defvar asc-scroll-up-function 'asc-scroll-up0)
(defun asc-scroll-up (up)
  (funcall asc-scroll-up-function up))
(apply 'use-anything-show-completeion*
       '(anything-zsh-screen-complete
         (anything-zsh-screen-get-prefix-length)
         asc-scroll-display-function
         (defadvice anything-zsh-screen-complete (after scroll-up activate)
           (when (not (zerop asc-scroll))
             (asc-scroll-up asc-scroll)))))