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bug#69972: 29.1; Unexpected behavior when scrolling images
From: |
Eli Zaretskii |
Subject: |
bug#69972: 29.1; Unexpected behavior when scrolling images |
Date: |
Mon, 25 Mar 2024 14:23:28 +0200 |
> From: Joseph Turner <joseph@ushin.org>
> Cc: 69972@debbugs.gnu.org
> Date: Sun, 24 Mar 2024 18:06:44 -0700
>
> (with-current-buffer (get-buffer-create "*test-scroll-image*")
> (erase-buffer)
> (insert-image (create-image "splash.png" nil nil
> ;; Scale the image more if it doesn't take up the whole window.
> :scale 5))
> (goto-char (point-max))
> (pixel-scroll-precision-mode -1) ; Ensure mouse wheel scroll up and down
> works
> (pop-to-buffer (current-buffer)))
>
> 1. "M-: (scroll-up) RET" (repeatedly)
> 2. C-v (repeatedly)
> 3. <wheel-down> (repeatedly)
>
> With all three methods, at first Emacs gradually scrolls the image, but
> then when I reach the bottom of the image, the image disappears entirely
> as Emacs scrolls past it all at once.
Why is that a problem? The default Emacs scrolling commands don't
guarantee smooth constant-rate scrolling, they guarantee only that you
get to see all the portions of the image, without missing any. So
when you get to the end of the image, there's a heuristic that decides
whether we can scroll past the image, and that is what you see.
I see no bug here.