Re: 'struct window' cleanup #4

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Date: Mon, 02 Jul 2012 10:48:08 -0400
> Cc: Emacs development discussions <emacs-devel@gnu.org>
> 
> vscroll should be int, as should be the hscroll amounts.
> The vpos probably as well.

I agree, on all 3 counts.  Since the corresponding coordinates in
pixel units (current_x and current_y from 'struct it'), which are
typically about 10 times larger than the above 3, are ints, it doesn't
make sense to have these declared as ptrdiff_t.

Vertical and horizontal screen positions are generally the size of the
Emacs window, i.e. bounded by the display size.  (Some internal Emacs
display routines simulate a larger window for the purposes of
adjusting the displayed area, e.g., while scrolling.  But they never
go too far outside the display dimensions, because doing so makes the
display sluggish, and people complain sooner or later.)  Those values
are a far cry from being anywhere near INT_MAX.