display-pixel-height not working as advertized

display-pixel-height not working as advertized

[John Wiegley]

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In GNU Emacs 21.2.1 (i386-debian-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2002-03-22 on raven, modified by Debian
configured using `configure  i386-debian-linux-gnu --prefix=/usr --sharedstatedir=/var/lib --libexecdir=/usr/lib --localstatedir=/var/lib --infodir=/usr/share/info --mandir=/usr/share/man --with-pop=yes --with-x=yes --with-x-toolkit=athena --without-gif'
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: C
  locale-coding-system: nil
  default-enable-multibyte-characters: t

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

(display-pixel-height "some.host.com:0.0") should return the X display
height in pixels.  Instead, it always returns my own display's height
in characters!

This seems to be because (framep-on-display "some.host.com:0") always
returns nil.

(x-display-pixel-height "some.host.com:0.0") returns what I expect.

John

Re: display-pixel-height not working as advertized

[Eli Zaretskii]

On Mon, 8 Apr 2002, John Wiegley wrote:

> (display-pixel-height "some.host.com:0.0") should return the X display
> height in pixels.  Instead, it always returns my own display's height
> in characters!
> 
> This seems to be because (framep-on-display "some.host.com:0") always
> returns nil.

Thanks.  Could you please step through frame-on-display and its 
subroutines, and see why does it return nil?

Re: display-pixel-height not working as advertized

[Richard Stallman]

    This seems to be because (framep-on-display "some.host.com:0") always
    returns nil.

Since the failure is happening on your machine, could you debug why it
fails?

Re: display-pixel-height not working as advertized

[John Paul Wallington]

Richard Stallman <rms@gnu.org> wrote:

>     This seems to be because (framep-on-display "some.host.com:0") always
>     returns nil.
>
> Since the failure is happening on your machine, could you debug why it
> fails?

Should `frames-on-display-list' use equal instead of eq ?

(defun frames-on-display-list (&optional display)
  "Return a list of all frames on DISPLAY.
DISPLAY is a name of a display, a string of the form HOST:SERVER.SCREEN.
If DISPLAY is omitted or nil, it defaults to the selected frame's display."
  (let* ((display (or display (frame-parameter nil 'display)))
	 (func #'(lambda (frame)
-		   (eq (frame-parameter frame 'display) display))))
+		   (equal (frame-parameter frame 'display) display))))
    (filtered-frame-list func)))

-- 
John Paul Wallington

Re: display-pixel-height not working as advertized

[Richard Stallman]

I think you found the problem and the right fix.
Thanks.