Re: x-display-pixel-width/height inconsistency

[YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>]

>>>>> On Fri, 22 Mar 2013 12:33:36 +0200, Eli Zaretskii <eliz@gnu.org> said:

> How did you deduce that SM_CXVIRTUALSCREEN and SM_CYVIRTUALSCREEN
> are not available on those old systems?  Can you point me to some
> documentation which has the details?

http://msdn.microsoft.com/ja-jp/library/cc429812.aspx
(in Japanese.  But probably you can find "Window 98" and "Windows
2000" around SM_CXVIRTUALSCREEN/SM_CYVIRTUALSCREEN)

I couldn't find a corresponding document in English.

> If we do need to distinguish those systems, there's os_subtype
> variable, which can help you be sure that you include both Windows
> 9X and NT 4.0, as version info on 9X is somewhat tricky.

I think it is enough to distinguish Windows 95 and Windows NT 4.0 from
the other versions, and both 95 and NT4 seem to have the same major
and minor versions (4 and 0) maybe by accident, while they have
different os_subtype values.  (Correct me if wrong.)

> I'm bothered by the fact that you change the behavior of these
> functions in backward-incompatible ways, without properly
> documenting what values they return.  The new doc strings do not add
> _anything_ to the vagueness of the previous description wrt what
> exactly are the "display dimensions".  Now, you may be right about
> what these primitives do on X11 (I don't know enough about that to
> tell, and the man pages I've seen are not helpful), but if so, we
> should clearly document their semantics, either in the doc strings
> or/and in the ELisp manual.  We certainly should mention the change
> in behavior in NEWS.

As I've already mentioned, the elisp info already contains the
description about the semantics under multi-monitor setups.

  http://lists.gnu.org/archive/html/emacs-devel/2013-03/msg00469.html

Probably we can copy it to the doc strings if necessary.  Previously
only the info was updated by a maintainer (see the thread starting
from http://lists.gnu.org/archive/html/emacs-devel/2007-04/msg00400.html).

> Personally, I am still unsure how will dimensions of "the bounding
> rectangle of all display monitors" be helpful to any Lisp program;
> can you tell why you think returning that is a good idea?  Maybe we
> should change the X11 implementation instead?

Please look at my other posts:

  http://lists.gnu.org/archive/html/emacs-devel/2013-03/msg00553.html
  http://lists.gnu.org/archive/html/emacs-devel/2013-03/msg00555.html

				     YAMAMOTO Mitsuharu
				mituharu@math.s.chiba-u.ac.jp