Re: window-scroll-functions called too often

[Ryan Yeske <rcyeske@gmail.com>]

   I suggest you copy the method used by comint.
   It works.

Here is patch for a simplified version of the comint method.  It just
scrolls to keep the point at the bottom of the window on user input
and on incoming text.

2006-09-07  Ryan Yeske  <rcyeske@gmail.com>

	* rcirc.el (rcirc-scroll-show-maximum-output): Rename from
	rcirc-show-maximum-output.
	(rcirc-mode): Remove window-scroll-function hook.
	(rcirc-scroll-to-bottom): Remove function.
	(rcirc-print): Recenter so point stays at the bottom of the window
	if point was already there.

*** rcirc.el	05 Sep 2006 12:14:49 -0700	1.26
--- rcirc.el	07 Sep 2006 17:01:51 -0700	
***************
*** 142,148 ****
  		 (integer :tag "Number of lines"))
    :group 'rcirc)
  
! (defcustom rcirc-show-maximum-output t
    "*If non-nil, scroll buffer to keep the point at the bottom of
  the window."
    :type 'boolean
--- 142,148 ----
  		 (integer :tag "Number of lines"))
    :group 'rcirc)
  
! (defcustom rcirc-scroll-show-maximum-output t
    "*If non-nil, scroll buffer to keep the point at the bottom of
  the window."
    :type 'boolean
***************
*** 762,769 ****
    (add-hook 'change-major-mode-hook 'rcirc-change-major-mode-hook nil t)
    (add-hook 'kill-buffer-hook 'rcirc-kill-buffer-hook nil t)
  
-   (add-hook 'window-scroll-functions 'rcirc-scroll-to-bottom nil t)
- 
    ;; add to buffer list, and update buffer abbrevs
    (when target				; skip server buffer
      (let ((buffer (current-buffer)))
--- 762,767 ----
***************
*** 1166,1179 ****
  (defvar rcirc-last-sender nil)
  (make-variable-buffer-local 'rcirc-last-sender)
  
- (defun rcirc-scroll-to-bottom (window display-start)
-   "Scroll window to show maximum output if `rcirc-show-maximum-output' is
- non-nil."
-   (when rcirc-show-maximum-output
-     (with-selected-window window
-       (when (>= (window-point) rcirc-prompt-end-marker)
- 	(recenter -1)))))
- 
  (defun rcirc-print (process sender response target text &optional activity)
    "Print TEXT in the buffer associated with TARGET.
  Format based on SENDER and RESPONSE.  If ACTIVITY is non-nil,
--- 1164,1169 ----
***************
*** 1252,1268 ****
  
  	  ;; set the window point for buffers show in windows
  	  (walk-windows (lambda (w)
! 			  (unless (eq (selected-window) w)
! 			    (when (and (eq (current-buffer)
! 					   (window-buffer w))
! 				       (>= (window-point w)
! 					   rcirc-prompt-end-marker))
! 			      (set-window-point w (point-max)))))
  			nil t)
  
  	  ;; restore the point
  	  (goto-char (if moving rcirc-prompt-end-marker old-point))
  
  	  ;; flush undo (can we do something smarter here?)
  	  (buffer-disable-undo)
  	  (buffer-enable-undo))
--- 1242,1275 ----
  
  	  ;; set the window point for buffers show in windows
  	  (walk-windows (lambda (w)
! 			  (when (and (not (eq (selected-window) w))
! 				     (eq (current-buffer)
! 					 (window-buffer w))
! 				     (>= (window-point w)
! 					 rcirc-prompt-end-marker))
! 			      (set-window-point w (point-max))))
  			nil t)
  
  	  ;; restore the point
  	  (goto-char (if moving rcirc-prompt-end-marker old-point))
  
+ 	  ;; keep window on bottom line if it was already there
+ 	  (when rcirc-scroll-show-maximum-output
+ 	    (walk-windows (lambda (w)
+ 			    (when (eq (window-buffer w) (current-buffer))
+ 			      (with-current-buffer (window-buffer w)
+ 				(when (eq major-mode 'rcirc-mode)
+ 				  (with-selected-window w
+ 				    (when (<= (- (window-height) 
+ 						 (- (line-number-at-pos
+ 						     (window-point))
+ 						    (line-number-at-pos
+ 						     (window-start)))
+ 						 1)
+ 					      0)
+ 				      (recenter -1)))))))
+ 				  nil t))
+ 
  	  ;; flush undo (can we do something smarter here?)
  	  (buffer-disable-undo)
  	  (buffer-enable-undo))