Re: Bug in CVS Emacs frame positioning under X

[Fran Litterio]

On 3/22/06, I (Fran Litterio) wrote:
> On 3/22/06, Richard Stallman wrote:
> >     In the latest CVS Emacs under X, there seems to be a frame positioning 
> > bug that
> >     is timing related.
> >
> > Does it happen in older CVS versions too?  For instance,
> > did it happen a month ago?  6 months ago?
>
> Unknown.  I'll check-out the older sources and rebuild.  I'll let you know.

I have checked out the CVS Emacs source code from October 1, 2005, and
the bug existed at that time.  Additionally, I have found a simple way
to reproduce the problem:

1. Start Emacs under the X Window system using the command: emacs -q

2. Evaluate the following Elisp:

        (dolist (i '(1 2 3 4 5 6))
          (let ((frame (make-frame '((top . 50) (left . 50)))))
            (set-frame-position frame 200 200)
            (set-frame-position frame 300 300)
            (sit-for 0.5)))

You may have to evaluate the above Elisp more than once to see the
malfunction (although I see it every time).

The symptom is that not all of the frames end up positioned at x/y
coordinates 300/300.  Some frames are positioned at 300+A/300+B, where
A is the width of the left border drawn by the window manager and B is
the height of the top border drawn by the window manager.  Some frames
even end up at 400/400 !

I think I have a patch to src/xterm.c that may fix this.  I will try
it and let you know if the patch works.
--
Fran Litterio