+;; Return position of start of line LINE in WINDOW.
+;; If LINE is nil, return the last position
+;; visible in WINDOW.
+(defun event-closest-point-1 (window &optional line)
+ (let* ((total (- (window-height window)
+ (if (window-minibuffer-p window)
+ 0 1)))
+ (distance (or line total)))
+ (save-excursion
+ (goto-char (window-start window))
+ (if (= (vertical-motion distance) distance)
+ (if (not line)
+ (forward-char -1)))
+ (point))))
+
+(defun event-closest-point (event &optional start-window)
+ "Return the nearest position to where EVENT ended its motion.
+This is computed for the window where EVENT's motion started,
+or for window WINDOW if that is specified."
+ (or start-window (setq start-window (posn-window (event-start event))))
+ (if (eq start-window (posn-window (event-end event)))
+ (if (eq (event-point event) 'vertical-line)
+ (event-closest-point-1 start-window
+ (cdr (posn-col-row (event-end event))))
+ (if (eq (event-point event) 'mode-line)
+ (event-closest-point-1 start-window)
+ (event-point event)))
+ ;; EVENT ended in some other window.
+ (let* ((end-w (posn-window (event-end event)))
+ (end-w-top)
+ (w-top (nth 1 (window-edges start-window))))
+ (setq end-w-top
+ (if (windowp end-w)
+ (nth 1 (window-edges end-w))
+ (/ (cdr (posn-x-y (event-end event)))
+ (frame-char-height end-w))))
+ (if (>= end-w-top w-top)
+ (event-closest-point-1 start-window)
+ (window-start start-window)))))
+