From: Rahguzar via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
To: Rahguzar <rahguzar@zohomail.eu>
Cc: Po Lu <luangruo@yahoo.com>, 65214@debbugs.gnu.org
Subject: bug#65214: 29.1; Tall images in 'image-mode' can't be scrolled with 'pixel-scroll-precision-mode' on
Date: Fri, 11 Aug 2023 16:39:22 +0200 [thread overview]
Message-ID: <871qg9d4mp.fsf@zohomail.eu> (raw)
In-Reply-To: <875y5ld55b.fsf@zohomail.eu>
The diff in my last message was not correct, sorry about that. It should
be
@@ -524,12 +524,15 @@ pixel-scroll-precision-scroll-down-page
(next-pos (save-excursion
(goto-char desired-start)
(when (zerop (vertical-motion (1+ scroll-margin)))
- (set-window-start nil desired-start)
- (signal 'end-of-buffer nil))
+ (unless (let ((remaining-bottom (nth 3 (pos-visible-in-window-p desired-start nil t))))
+ (and remaining-bottom (not (zerop remaining-bottom))))
+ (set-window-start nil desired-start t)
+ (signal 'end-of-buffer nil)))
(while (when-let ((posn (posn-at-point)))
- (< (cdr (posn-x-y posn)) delta))
+ (and (< (point) (point-min))
+ (< (cdr (posn-x-y posn)) delta)))
(when (zerop (vertical-motion 1))
- (set-window-start nil desired-start)
+ (set-window-start nil desired-start t)
(signal 'end-of-buffer nil)))
(point)))
(scroll-preserve-screen-position nil)
Rahguzar <rahguzar@zohomail.eu> writes:
> Hi Po,
> In this case it is not the recentering which is causing this problem,
> it is rather the binding for next-pos in
> pixel-scroll-precision-scroll-down-page which is the issue. The
> binding signals an error when downward vertical motion is not
> possible. However in this scenario scrolling can still be done.
> Replacing that binding with desired-start allow me to scroll the
> images.
>
> This change for example allows for scrolling tall images,
> @@ -524,10 +524,12 @@ pixel-scroll-precision-scroll-down-page
> (next-pos (save-excursion
> (goto-char desired-start)
> (when (zerop (vertical-motion (1+ scroll-margin)))
> - (set-window-start nil desired-start)
> - (signal 'end-of-buffer nil))
> + (unless (let ((remaining-bottom (nth 3 (pos-visible-in-window-p desired-start nil t))))
> + (and remaining-bottom (not (zerop remaining-bottom))))
> + (signal 'end-of-buffer nil)))
> (while (when-let ((posn (posn-at-point)))
> - (< (cdr (posn-x-y posn)) delta))
> + (and (< (point) (point-min))
> + (< (cdr (posn-x-y posn)) delta)))
> (when (zerop (vertical-motion 1))
> (set-window-start nil desired-start)
> (signal 'end-of-buffer nil)))
>
> I am not sure it is the correct change since I don't understand the
> while loop but comparing 'point' and 'point-min' doesn't seem the write
> thing there. On the others hand if there is 'point-min' is 1 and
> 'point-max' 2, (cdr (posn-x-y posn))
>
> Po Lu <luangruo@yahoo.com> writes:
>
>> This is a known limitation of pixel-scroll-precision-mode: redisplay's
>> automatic recentering impededs adjustment of the vscroll as the image
>> moves outside of the window's text area. Unfortunately, it's not slated
>> to be fixed any time soon.
>
> In this case it is not the recentering which is causing this problem,
> it is rather the binding for next-pos in
> pixel-scroll-precision-scroll-down-page which is the issue. The
> binding signals an error when downward vertical motion is not
> possible. However in this scenario scrolling can still be done.
> Replacing that binding with desired-start allow me to scroll the
> images.
>
> This change for example allows for scrolling tall images,
> @@ -524,10 +524,12 @@ pixel-scroll-precision-scroll-down-page
> (next-pos (save-excursion
> (goto-char desired-start)
> (when (zerop (vertical-motion (1+ scroll-margin)))
> - (set-window-start nil desired-start)
> - (signal 'end-of-buffer nil))
> + (unless (let ((remaining-bottom (nth 3 (pos-visible-in-window-p desired-start nil t))))
> + (and remaining-bottom (not (zerop remaining-bottom))))
> + (signal 'end-of-buffer nil)))
> (while (when-let ((posn (posn-at-point)))
> - (< (cdr (posn-x-y posn)) delta))
> + (and (< (point) (point-min))
> + (< (cdr (posn-x-y posn)) delta)))
> (when (zerop (vertical-motion 1))
> (set-window-start nil desired-start)
> (signal 'end-of-buffer nil)))
>
> I am not sure it is the correct change since I don't understand the
> while loop but comparing 'point' and 'point-min' doesn't seem the write
> thing there. On the others hand if there is 'point-min' is 1 and
> 'point-max' 2, (cdr (posn-x-y posn)) is always zero, so that check makes
> the loop terminate without signaling an error.
>
> The behavior is also sub optimal in that it allows for scrolling past
> the lower edge of the image but how much depends on the speed of the
> scrolling, but that can be fixed easily.
>
> Rahguzar
next prev parent reply other threads:[~2023-08-11 14:39 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-10 17:05 bug#65214: 29.1; Tall images in 'image-mode' can't be scrolled with 'pixel-scroll-precision-mode' on Rahguzar via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-11 3:38 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-11 13:19 ` Rahguzar via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-11 14:39 ` Rahguzar via Bug reports for GNU Emacs, the Swiss army knife of text editors [this message]
2023-08-12 2:22 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-12 6:50 ` Rahguzar via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-12 7:25 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-12 10:43 ` Rahguzar via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-27 7:53 ` Rahguzar via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-27 8:16 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-27 8:53 ` Rahguzar via Bug reports for GNU Emacs, the Swiss army knife of text editors
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