(global-set-key  [f12]  'simple-doit-2)

(defun  simple-doit-2  ()
  
  "Tests fit-frame-to-buffer."
  
  (interactive)
  
  (let  ((simple-frame   (make-frame  `((name       . "Simple Frame")
                                        (visibility . ,simple-visibility))) )
         (simple-buffer  (get-buffer-create  "Simple Buffer")))
    
    (set-window-buffer  (frame-selected-window  simple-frame)  simple-buffer)    
    (with-current-buffer  simple-buffer  (erase-buffer)
                          (insert  (format  "version %s"  .emacs-current-emacs-version)))
;;;    (raise-frame  simple-frame)
    
    (let*  ((invoking-frame  (selected-frame))
            (newish          (<=  25.1  (string-to-number  .emacs-current-emacs-version)))
            (invoke-origin   (if  newish
                                 (frame-position  invoking-frame)
                               '(0 . 25)))
            (invoke-left  (car  invoke-origin))
            (invoke-top   (cdr  invoke-origin))
            (left         -41)
            (top          invoke-top)
            (width        60)
            (height       6))
      
      (unwind-protect
          (while  (progn
;;;                    (set-frame-size  simple-frame  width  height)
                    (set-frame-position  simple-frame  left  top)
                    (or  (frame-visible-p  simple-frame)
                         (raise-frame  simple-frame))
                    (select-frame-set-input-focus  simple-frame)
                    (set-buffer  simple-buffer)
                    (goto-char  (point-max))
                      (insert  (format  "\n%s  l:%3d  t:%3d  w:%3d  h:%3d"
                                        (selected-frame)  left  top  width  height))
                    (fit-frame-to-buffer  simple-frame)

                    (setq  left   (+  left  10)                   
                           top    (+  top   10)
                           height (+  height 1))
                    (if  newish  (discard-input))
                    
                    ;; loop test
                     (not  (equal
                             (read-event  "press any key to continue, escape to terminate")
                           'escape))) )
        ;; end no body while
        
        ;; Protected.
        (select-frame  invoking-frame)
        (delete-frame  simple-frame))) ))