(defvar beacon--previous-mark-head nil)
(defvar beacon--previous-window nil)
+(defun beacon--pos-on-current-line-p (pos)
+ "Return non-nil if POS is on the current line."
+ (and (<= (save-excursion (beginning-of-line) (point)) pos)
+ (<= pos (save-excursion (end-of-line) (point)))))
+
(defun beacon--movement-> (delta)
"Return non-nil if latest point movement is > DELTA.
If DELTA is nil, return nil."
(current-buffer))
(> (abs (- (point) beacon--previous-place))
delta)
- (> (count-screen-lines (min (point) beacon--previous-place)
- (max (point) beacon--previous-place))
- delta)))
+ ;; Check if the movement was larger than DELTA lines by testing if
+ ;; `point' is still on the same line or on any line DELTA lines up or
+ ;; down. This is much cheaper than computing the actual number of lines
+ ;; moved using `count-screen-lines'.
+ (let ((prev-pos (marker-position beacon--previous-place)))
+ (catch 'movement
+ (when (beacon--pos-on-current-line-p prev-pos)
+ (throw 'movement nil))
+ (dolist (inc '(1 -1))
+ (save-excursion
+ (dotimes (i delta)
+ (vertical-motion inc)
+ (when (beacon--pos-on-current-line-p prev-pos)
+ (throw 'movement nil)))))
+ (throw 'movement t)))))
(defun beacon--maybe-push-mark ()
"Push mark if it seems to be safe."