Re: Stipples and scroll optimizations

[Eli Zaretskii]

> From: Po Lu <luangruo@yahoo.com>
> Date: Sun, 08 May 2022 15:22:34 +0800
> 
> When a glyph with a stipple background is displayed in the scrolled area
> of the screen, the optimization in `scrolling_window' should not be
> performed.  This is because stipples are "tiled" across the screen from
> a constant origin, so the display of the stipple might not be correct
> after it is copied to a different part of the frame.
> 
> That problem can easily be seen by setting the stipple of the default
> face to `dimple1' and scrolling a little.
> 
> WDYT about such a change?

If using scrolling_window in this case causes incorrect display, then
scrolling_window should be disabled.  But how would you know, in
update_window or its subroutines, that this is the case?