Re: How to add a temporary blank line at the end of buffer safely

[Eli Zaretskii <eliz@gnu.org>]

> Date: Thu, 11 Jan 2018 16:45:43 +0800 (CST)
> From: tumashu <tumashu@163.com>
> 
> Doesn't vertical-motion fit the bill?  If not, why not?
> ------------------------------------------------------------------------
> @Eli Zaretskii Thanks for your suggestion, it works very well,  the only problem is that 
> it can not work when point at the end line of buffer, I use the below code to handle this problem, 
> (add a temp "\n" then remove) but it seem to hacky.  any good way to solve this problem:

Something like the below, perhaps?

  (aref (font-info (font-at POS)) 3)

This will give you the height of the font used at position POS.  Then
you could add that to the y-coordinate of the line at EOB, to get the
bottom y-coordinate of that line.  (Caveat: font-at doesn't like to be
called at EOB, so make sure you are one buffer position before that.)