+ (move-to-window-line this-scroll-margin))
+ ((eq recenter-last-op 'bottom)
+ (move-to-window-line (- -1 this-scroll-margin)))
+ ((integerp recenter-last-op)
+ (move-to-window-line recenter-last-op))
+ ((floatp recenter-last-op)
+ (move-to-window-line (round (* recenter-last-op (window-height))))))))))
+
+(define-key global-map [?\M-r] 'move-to-window-line-top-bottom)
+
+\f
+;;; Scrolling commands.
+
+;;; Scrolling commands which does not signal errors at top/bottom
+;;; of buffer at first key-press (instead moves to top/bottom
+;;; of buffer).
+
+(defcustom scroll-error-top-bottom nil
+ "Move point to top/bottom of buffer before signalling a scrolling error.
+A value of nil means just signal an error if no more scrolling possible.
+A value of t means point moves to the beginning or the end of the buffer
+\(depending on scrolling direction) when no more scrolling possible.
+When point is already on that position, then signal an error."
+ :type 'boolean
+ :group 'scrolling
+ :version "24.1")
+
+(defun scroll-up-command (&optional arg)
+ "Scroll text of selected window upward ARG lines; or near full screen if no ARG.
+If `scroll-error-top-bottom' is non-nil and `scroll-up' cannot
+scroll window further, move cursor to the bottom line.
+When point is already on that position, then signal an error.
+A near full screen is `next-screen-context-lines' less than a full screen.
+Negative ARG means scroll downward.
+If ARG is the atom `-', scroll downward by nearly full screen."
+ (interactive "^P")
+ (cond
+ ((null scroll-error-top-bottom)
+ (scroll-up arg))
+ ((eq arg '-)
+ (scroll-down-command nil))
+ ((< (prefix-numeric-value arg) 0)
+ (scroll-down-command (- (prefix-numeric-value arg))))
+ ((eobp)
+ (scroll-up arg)) ; signal error
+ (t
+ (condition-case nil
+ (scroll-up arg)
+ (end-of-buffer
+ (if arg
+ ;; When scrolling by ARG lines can't be done,
+ ;; move by ARG lines instead.
+ (forward-line arg)
+ ;; When ARG is nil for full-screen scrolling,
+ ;; move to the bottom of the buffer.
+ (goto-char (point-max))))))))
+
+(put 'scroll-up-command 'scroll-command t)
+
+(defun scroll-down-command (&optional arg)
+ "Scroll text of selected window down ARG lines; or near full screen if no ARG.
+If `scroll-error-top-bottom' is non-nil and `scroll-down' cannot
+scroll window further, move cursor to the top line.
+When point is already on that position, then signal an error.
+A near full screen is `next-screen-context-lines' less than a full screen.
+Negative ARG means scroll upward.
+If ARG is the atom `-', scroll upward by nearly full screen."
+ (interactive "^P")
+ (cond
+ ((null scroll-error-top-bottom)
+ (scroll-down arg))
+ ((eq arg '-)
+ (scroll-up-command nil))
+ ((< (prefix-numeric-value arg) 0)
+ (scroll-up-command (- (prefix-numeric-value arg))))
+ ((bobp)
+ (scroll-down arg)) ; signal error
+ (t
+ (condition-case nil
+ (scroll-down arg)
+ (beginning-of-buffer
+ (if arg
+ ;; When scrolling by ARG lines can't be done,
+ ;; move by ARG lines instead.
+ (forward-line (- arg))
+ ;; When ARG is nil for full-screen scrolling,
+ ;; move to the top of the buffer.
+ (goto-char (point-min))))))))
+
+(put 'scroll-down-command 'scroll-command t)
+
+;;; Scrolling commands which scroll a line instead of full screen.
+
+(defun scroll-up-line (&optional arg)
+ "Scroll text of selected window upward ARG lines; or one line if no ARG.
+If ARG is omitted or nil, scroll upward by one line.
+This is different from `scroll-up-command' that scrolls a full screen."
+ (interactive "p")
+ (scroll-up (or arg 1)))
+
+(put 'scroll-up-line 'scroll-command t)
+
+(defun scroll-down-line (&optional arg)
+ "Scroll text of selected window down ARG lines; or one line if no ARG.
+If ARG is omitted or nil, scroll down by one line.
+This is different from `scroll-down-command' that scrolls a full screen."
+ (interactive "p")
+ (scroll-down (or arg 1)))
+
+(put 'scroll-down-line 'scroll-command t)
+
+\f
+(defun scroll-other-window-down (lines)
+ "Scroll the \"other window\" down.
+For more details, see the documentation for `scroll-other-window'."
+ (interactive "P")
+ (scroll-other-window
+ ;; Just invert the argument's meaning.
+ ;; We can do that without knowing which window it will be.
+ (if (eq lines '-) nil
+ (if (null lines) '-
+ (- (prefix-numeric-value lines))))))
+
+(defun beginning-of-buffer-other-window (arg)
+ "Move point to the beginning of the buffer in the other window.
+Leave mark at previous position.
+With arg N, put point N/10 of the way from the true beginning."
+ (interactive "P")
+ (let ((orig-window (selected-window))
+ (window (other-window-for-scrolling)))
+ ;; We use unwind-protect rather than save-window-excursion
+ ;; because the latter would preserve the things we want to change.
+ (unwind-protect
+ (progn
+ (select-window window)
+ ;; Set point and mark in that window's buffer.
+ (with-no-warnings
+ (beginning-of-buffer arg))
+ ;; Set point accordingly.
+ (recenter '(t)))
+ (select-window orig-window))))
+
+(defun end-of-buffer-other-window (arg)
+ "Move point to the end of the buffer in the other window.
+Leave mark at previous position.
+With arg N, put point N/10 of the way from the true end."
+ (interactive "P")
+ ;; See beginning-of-buffer-other-window for comments.
+ (let ((orig-window (selected-window))
+ (window (other-window-for-scrolling)))
+ (unwind-protect
+ (progn
+ (select-window window)
+ (with-no-warnings
+ (end-of-buffer arg))
+ (recenter '(t)))
+ (select-window orig-window))))