diff options
Diffstat (limited to 'lisp/pixel-scroll.el')
| -rw-r--r-- | lisp/pixel-scroll.el | 71 |
1 files changed, 48 insertions, 23 deletions
diff --git a/lisp/pixel-scroll.el b/lisp/pixel-scroll.el index bfc48bac2e2..d362419e0fc 100644 --- a/lisp/pixel-scroll.el +++ b/lisp/pixel-scroll.el @@ -82,6 +82,27 @@ case you need scrolling resolution of a pixel, set to 1. After a pixel scroll, typing \\[next-line] or \\[previous-line] scrolls the window to make it fully visible, and undoes the effect of the pixel-level scroll.") +(defvar pixel-dead-time 0.1 + "Minimal interval in seconds before next smooth scrolling. +If another scrolling request arrives within this period, scrolling +will be carried out without pixel resolution. If zero, scrolling +is always with pixel resolution.") + +(defvar pixel-last-scroll-time 0 + "Time when the last scrolling was made, in second since the epoch.") + +(defun pixel-scroll-in-rush-p () + "Return non-nil if next scroll should be non-smooth. +When scrolling request is delivered soon after the previous one, +user is in hurry. When the time since last scroll is larger than +`pixel-dead-time', we are ready for another smooth scroll, and this +function returns nil." + (let* ((current-time (float-time)) + (scroll-in-rush-p (< (- current-time pixel-last-scroll-time) + pixel-dead-time))) + (setq pixel-last-scroll-time current-time) + scroll-in-rush-p)) + ;;;###autoload (define-minor-mode pixel-scroll-mode "A minor mode to scroll text pixel-by-pixel. @@ -104,35 +125,39 @@ if ARG is omitted or nil." This is an alternative of `scroll-up'. Scope moves downward." (interactive) (or arg (setq arg 1)) - (dotimes (ii arg) ; move scope downward - (let ((amt (if pixel-resolution-fine-flag - (if (integerp pixel-resolution-fine-flag) - pixel-resolution-fine-flag - (frame-char-height)) - (pixel-line-height)))) - (if (pixel-eob-at-top-p) ; when end-of-the-buffer is close - (scroll-up 1) ; relay on robust method - (while (pixel-point-at-top-p amt) ; prevent too late (multi tries) - (vertical-motion 1)) ; move point downward - (pixel-scroll-pixel-up amt))))) ; move scope downward + (if (pixel-scroll-in-rush-p) + (scroll-up arg) + (dotimes (ii arg) ; move scope downward + (let ((amt (if pixel-resolution-fine-flag + (if (integerp pixel-resolution-fine-flag) + pixel-resolution-fine-flag + (frame-char-height)) + (pixel-line-height)))) + (if (pixel-eob-at-top-p) ; when end-of-the-buffer is close + (scroll-up 1) ; relay on robust method + (while (pixel-point-at-top-p amt) ; prevent too late (multi tries) + (vertical-motion 1)) ; move point downward + (pixel-scroll-pixel-up amt)))))) ; move scope downward (defun pixel-scroll-down (&optional arg) "Scroll text of selected window down ARG lines. This is and alternative of `scroll-down'. Scope moves upward." (interactive) (or arg (setq arg 1)) - (dotimes (ii arg) - (let ((amt (if pixel-resolution-fine-flag - (if (integerp pixel-resolution-fine-flag) - pixel-resolution-fine-flag - (frame-char-height)) - (pixel-line-height -1)))) - (while (pixel-point-at-bottom-p amt) ; prevent too late (multi tries) - (vertical-motion -1)) ; move point upward - (if (or (pixel-bob-at-top-p amt) ; when beginning-of-the-buffer is seen - (pixel-eob-at-top-p)) ; for file with a long line - (scroll-down 1) ; relay on robust method - (pixel-scroll-pixel-down amt))))) + (if (pixel-scroll-in-rush-p) + (scroll-down arg) + (dotimes (ii arg) + (let ((amt (if pixel-resolution-fine-flag + (if (integerp pixel-resolution-fine-flag) + pixel-resolution-fine-flag + (frame-char-height)) + (pixel-line-height -1)))) + (while (pixel-point-at-bottom-p amt) ; prevent too late (multi tries) + (vertical-motion -1)) ; move point upward + (if (or (pixel-bob-at-top-p amt) ; when beginning-of-the-buffer is seen + (pixel-eob-at-top-p)) ; for file with a long line + (scroll-down 1) ; relay on robust method + (pixel-scroll-pixel-down amt)))))) (defun pixel-bob-at-top-p (amt) "Return non-nil if window-start is at beginning of the current buffer. |