Re: Changes in frame/window code

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 19 Aug 2014 18:15:58 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: emacs-devel@gnu.org
> 
> Btw, I don't understand why in w32_horizontal_scroll_bar_handle_click
> you overwrite the value reported from GetScrollInfo by
> HIWORD(msg->msg.wParam).  My reading of MSDN documentation is that
> they recommend to do it the other way around, since GetScrollInfo is
> not limited to 16-bit values.  If using the values reported by
> GetScrollInfo doesn't work well, perhaps that's because for
> SB_THUMBTRACK message you need to use SIF_TRACKPOS and si.nTrackPos
> rather than SIF_POS and si.nPos.

I switched to using the GetScrollInfo information (for both horizontal
and vertical scroll bars) in trunk revision 117716.  I didn't find any
reason for the current code, except, perhaps, the fact that an old
version of MSDN documentation didn't document SIF_TRACKPOS at all.
But since even the venerable "Programming Windows" by Petzold that was
published in 1998 described that value very well without any
qualifications for its support by various Windows versions we care
about, I think it's safe to use it.