A *big* problem with Emacs 29's pixel-scroll-precision-mode

Just tested out Emacs 29 on Arch today, and the *pixel-scroll-precision-mode* is really quite smooth! I'm very content with it until I noticed one big **problem**: If the scrolling doesn't stop exactly at full lines, that is, if the top of the frame is cutting the top half of some line, then as soon as the user starts editing with the cursor, the Emacs buffer will "**adjust**" itself such that the top of the frame is starting with a whole line, often through scrolling a few pixels up or down. This results in a visual **jitter** when the user is done scrolling (e.g. with the trackpad) and **right after one starts using the keyboard** to edit the text. I'm not sure if I've articulated the behavior clearly enough, but I'd love to know if others are facing the same issue, and whether there are workarounds for this. One potential solution that I could think of is to "perform the pixel adjustment" (if needed) right after the user "stops" scrolling. Because it's less distracting then than when the user starts typing.

I think it's a nice improvement and you should write to the dev newsletter.

It works well on macOS. Run Emacs with `emacs -Q`, and try again, if the issue still exist, I think you can report the bug to Emacs dev team. `M-x , report-emacs-bug，` Add an title and your descriptions , an then send the contents to [bug-gnu-emacs@gnu.org](mailto:bug-gnu-emacs@gnu.org)

Where is your cursor when it happens? In the top line (the one that's cut), the one immediately below, or a few lines down (with a non-zero scroll-margin)?

fwiw, I experience the same on MacOS with master pulled this afternoon.

Please report this as a bug, with a minimal recipe to reproduce the problem.

I noticed if it reaches the top or bottom it is still trying to go up/down because I pressed meta(macos) right after it stopped scrolling and I got the fonts scaled up/down. Very anoying.