Subject: bug#56393: Actually fix the long lines display bug

From: Eli Zaretskii <[email-masked]>
Date: Sat, 09 Jul 2022 15:37:22 +0300

> From: Ihor Radchenko <[email-masked]>
> Cc: Gregory Heytings <[email-masked]>,  [email-masked],
>   [email-masked],  [email-masked]
> Date: Sat, 09 Jul 2022 20:09:42 +0800
> 
> I am not sure if it is related, but I do observe a slowdown when moving
> across fontified buffer. This happens in really large buffers when
> moving across invisible text. AFAIU, line-move-1 uses
> next-single-property-change loop, which could be costly when the region
> has a large number of discontinuous text properties.

Invisible text is a different matter altogether.  The problem there is
that the amount of text on the screen is very different from what's
actually in the buffer, and moving through such a buffer needs to skip
the invisible text, which isn't free.

Face properties don't have such an effect.