Re: Set-window-vscroll sometimes doesn't work

[Yuan Fu <casouri@gmail.com>]

> On Oct 19, 2020, at 12:59 AM, Yuan Fu <casouri@gmail.com> wrote:
> 
> 
> 
>> On Oct 18, 2020, at 10:23 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>> 
>>> From: Yuan Fu <casouri@gmail.com>
>>> Date: Sun, 18 Oct 2020 16:06:11 -0400
>>> Cc: help-gnu-emacs@gnu.org
>>> 
>>>>> 1. Is it true that move_it_by_lines regards an image as one display line?
>>>> 
>>>> Yes.  That's why we need vscroll in the first place.
>>> 
>>> Cool. I’m thinking about wrapping move_it_by_lines in window_scroll_pixel_based with a version that regards images (and tall lines) as several lines. Do you see some potential problems with that?
>> 
>> What is the problem with the existing code that you are trying to
>> solve?  Whatever it is, it is highly likely that the solution already
>> exists, and no new code is needed.
> 
> The problem I have is that when I scroll over images they jumps in and out of the window: (bad-scrolling.mp4)
> 
> <bad-scrolling.mp4>
> 
> What I want is to have the images smoothly scrolls in and out: (good-scrolling.mp4)
> 
> <good-scrolling.mp4>
> 
> Is there already a mean to do that?
> 
> Yuan
> 

Before you ask, I am aware of pixel-scroll-mode, but 1) it doesn’t handle the case when moving point instead of scrolling, 2) it’s performance is not very good, 3) scrolling by pixels isn’t really necessary, scrolling by single lines are fine enough.

Yuan