makes it possible to walk between windows using normal cursor
movement commands.
-Follow mode comes to its prime when used on a large screen and two
-side-by-side windows are used. The user can, with the help of Follow
-mode, use two full-height windows as though they would have been
-one. Imagine yourself editing a large function, or section of text,
-and being able to use 144 lines instead of the normal 72... (your
+Follow mode comes to its prime when used on a large screen and two or
+more side-by-side windows are used. The user can, with the help of
+Follow mode, use these full-height windows as though they were one.
+Imagine yourself editing a large function, or section of text, and
+being able to use 144 or 216 lines instead of the normal 72... (your
mileage may vary).
To split one large window into two side-by-side windows, the commands
;; position... (This would also be corrected if we would have had a
;; good redisplay abstraction.)
+(defun follow-scroll-up-arg (arg)
+ "Scroll the text in a follow mode window chain up by ARG lines.
+If ARG is nil, scroll the size of the current window.
+
+This is an internal function for `follow-scroll-up' and
+`follow-scroll-up-window'."
+ (let ((opoint (point)) (owin (selected-window)))
+ (while
+ ;; If we are too near EOB, try scrolling the previous window.
+ (condition-case nil (progn (scroll-up arg) nil)
+ (end-of-buffer
+ (condition-case nil (progn (follow-previous-window) t)
+ (error
+ (select-window owin)
+ (goto-char opoint)
+ (signal 'end-of-buffer nil))))))
+ (unless (and scroll-preserve-screen-position
+ (get this-command 'scroll-command))
+ (goto-char opoint))
+ (setq follow-fixed-window t)))
+
+(defun follow-scroll-down-arg (arg)
+ "Scroll the text in a follow mode window chain down by ARG lines.
+If ARG is nil, scroll the size of the current window.
+
+This is an internal function for `follow-scroll-down' and
+`follow-scroll-down-window'."
+ (let ((opoint (point)))
+ (scroll-down arg)
+ (unless (and scroll-preserve-screen-position
+ (get this-command 'scroll-command))
+ (goto-char opoint))
+ (setq follow-fixed-window t)))
+
+;;;###autoload
+(defun follow-scroll-up-window (&optional arg)
+ "Scroll text in a Follow mode window up by that window's size.
+The other windows in the window chain will scroll synchronously.
+
+If called with no ARG, the `next-screen-context-lines' last lines of
+the window will be visible after the scroll.
+
+If called with an argument, scroll ARG lines up.
+Negative ARG means scroll downward.
+
+Works like `scroll-up' when not in Follow mode."
+ (interactive "P")
+ (cond ((not follow-mode)
+ (scroll-up arg))
+ ((eq arg '-)
+ (follow-scroll-down-window))
+ (t (follow-scroll-up-arg arg))))
+(put 'follow-scroll-up-window 'scroll-command t)
+
+;;;###autoload
+(defun follow-scroll-down-window (&optional arg)
+ "Scroll text in a Follow mode window down by that window's size.
+The other windows in the window chain will scroll synchronously.
+
+If called with no ARG, the `next-screen-context-lines' top lines of
+the window in the chain will be visible after the scroll.
+
+If called with an argument, scroll ARG lines down.
+Negative ARG means scroll upward.
+
+Works like `scroll-down' when not in Follow mode."
+ (interactive "P")
+ (cond ((not follow-mode)
+ (scroll-down arg))
+ ((eq arg '-)
+ (follow-scroll-up-window))
+ (t (follow-scroll-down-arg arg))))
+(put 'follow-scroll-down-window 'scroll-command t)
+
;;;###autoload
(defun follow-scroll-up (&optional arg)
"Scroll text in a Follow mode window chain up.
(interactive "P")
(cond ((not follow-mode)
(scroll-up arg))
- ((eq arg '-)
- (follow-scroll-down))
- (t
- (let ((opoint (point)) (owin (selected-window)))
- (while
- ;; If we are too near EOB, try scrolling the previous window.
- (condition-case nil (progn (scroll-up arg) nil)
- (end-of-buffer
- (condition-case nil (progn (follow-previous-window) t)
- (error
- (select-window owin)
- (goto-char opoint)
- (signal 'end-of-buffer nil))))))
- (unless (and scroll-preserve-screen-position
- (get this-command 'scroll-command))
- (goto-char opoint))
- (setq follow-fixed-window t)))))
+ (arg (follow-scroll-up-arg arg))
+ (t
+ (let* ((windows (follow-all-followers))
+ (end (window-end (car (reverse windows)))))
+ (if (eq end (point-max))
+ (signal 'end-of-buffer nil)
+ (select-window (car windows))
+ ;; `window-end' might return nil.
+ (if end
+ (goto-char end))
+ (vertical-motion (- next-screen-context-lines))
+ (set-window-start (car windows) (point)))))))
(put 'follow-scroll-up 'scroll-command t)
;;;###autoload
(interactive "P")
(cond ((not follow-mode)
(scroll-down arg))
- ((eq arg '-)
- (follow-scroll-up))
- (t
- (let ((opoint (point)))
- (scroll-down arg)
- (unless (and scroll-preserve-screen-position
- (get this-command 'scroll-command))
- (goto-char opoint))
- (setq follow-fixed-window t)))))
+ (arg (follow-scroll-down-arg arg))
+ (t
+ (let* ((windows (follow-all-followers))
+ (win (car (reverse windows)))
+ (start (window-start (car windows))))
+ (if (eq start (point-min))
+ (signal 'beginning-of-buffer nil)
+ (select-window win)
+ (goto-char start)
+ (vertical-motion (- (- (window-height win)
+ (if header-line-format 2 1)
+ next-screen-context-lines)))
+ (set-window-start win (point))
+ (goto-char start)
+ (vertical-motion (- next-screen-context-lines 1))
+ (setq follow-internal-force-redisplay t))))))
(put 'follow-scroll-down 'scroll-command t)
(declare-function comint-adjust-point "comint" (window))