Re: "... the window start at a meaningless point within a line."

[Eli Zaretskii]

> Date: Sat, 17 Oct 2015 15:34:44 +0300
> From: Eli Zaretskii <address@hidden>
> Cc: address@hidden
> 
> So now I think that the problem can be solved as follows:
> 
>   . if Fvertical_motion's code without changes ends up before the
>     first newline that follows the window-start, you don't need to do
>     anything, because Fvertical_motion does exactly what you want in
>     that case
> 
>   . otherwise Fvertical_motion will either end up on the screen line
>     before the goal, or will be on the right screen line, but to the
>     right of the goal column, and a correction should be applied by
>     moving point to the left

Is the following a correct definition of when Fvertical_motion
overshoots, i.e. lands one line below (for LINES > 0) the correct one:
when the offset between the "actual" window-start and the preceding
"xdisp" BOL is greater than the X coordinate of the last character of
the 1st physical line in the window.