Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!psuvax1!wuarchive!husc6!encore!pierson
From: pierson@encore.com (Dan L. Pierson)
Newsgroups: comp.windows.x
Subject: Re: twm - What is size of title bar?
Message-ID: <PIERSON.90Oct15192238@xenna.encore.com>
Date: 15 Oct 90 23:22:38 GMT
References: <162@sdrc.UUCP> <1990Oct13.184110.13150@ux1.cso.uiuc.edu>
	<1990Oct15.140039.24990@Solbourne.COM>
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Distribution: usa
Organization: Encore Computer Corporation
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In-reply-to: toml@ninja.Solbourne.COM's message of 15 Oct 90 14:00:39 GMT

Regarding Re: twm - What is size of title bar?; toml@ninja.Solbourne.COM (Tom LaStrange) adds:
In article <1990Oct15.140039.24990@Solbourne.COM> toml@ninja.Solbourne.COM (Tom LaStrange) writes:
> In article <1990Oct13.184110.13150@ux1.cso.uiuc.edu>,
> carroll@sunc5.cs.uiuc.edu (Alan M. Carroll) writes: |> What we've
> done for this is to trace back the X window tree until you get a
> window |> whose parent is the root window, and then retrieve the
> screen information for that |> window. This can be compared to the
> information for the actual client window to |> determine the size of
> the various WM borders. I don't have any C code for this, |> but
> here's some Epoch code that does it -

> This will not work with tvtwm or any other window manager that
> places an extra window on top of the root window.  There really is
> no "standard" way to find out how big the decoration is around your
> window.

However this should:

;;; Utilities to find screen information for the tvtwm virtual root
;;; (or the real root if not running tvtwm).

(defun find-root (&optional start)
  (setq start (or start (current-screen)))
  (let ((tree (epoch::query-tree start)))
    (while (car (cdr tree))
      (setq tree (epoch::query-tree (car (cdr tree)))))
    tree))

;;; Standard Elisp control structures are very impoverished.  If
;;; you're willing to load cl.elc use this one, if not see below.
(defun find-virtual-root (&optional start)
  (do* ((vr-atom (epoch::intern-atom "__SWM_VROOT"))
	(tree (find-root start) (cdr tree))
	(win (car tree) (car tree))
	(root win)
	(ans nil))
       ((or ans (null tree))
	(or ans root))
    (when win
      (setq ans (epoch::get-property vr-atom win)))))

;;; Use this version to avoid using cl.ecl.
(defun find-virtual-root (&optional start)
  (let* ((vr-atom (epoch::intern-atom "__SWM_VROOT"))
	 (tree (find-root start))
	 (root (car tree)))
    (catch 'found-it 
      (while tree
	(let ((win (car tree)))
	  (setq tree (cdr tree))
	  (if win
	      (let ((ans (epoch::get-property vr-atom win)))
		(if ans
		    (progn
		      (setq root ans)
		      (throw 'found-it ans))))))))))

(defun backing-screen-info (&optional win)
  (let ((root (find-virtual-root (or win (current-screen)))))
    (and root (screen-information root))))
--

                                            dan

In real life: Dan Pierson, Encore Computer Corporation, Research
UUCP: {talcott,linus,necis,decvax}!encore!pierson
Internet: pierson@encore.com