Subject: bug#19060: [FIX INCLUDED] Off-by-one-line scrolling bug in window_scroll_pixel_based

From: martin rudalics <[email-masked]>
Date: Sat, 15 Nov 2014 15:32:41 +0100

> Since the issue is rounding vs truncating, perhaps try playing with
 > the portion of the last displayed line, trying both less and greater
 > than half the canonical line height.

Got it.  The last line must show more than a half of the frame's
character height.  And the patch fixes it AFAICT.  So please apply it
with as much comment as you can provide.

Thanks, martin