redisplay probs

redisplay probs

[Miles Bader]

Redisplay seems screwed up, such that it often fails to update the
screen when it should.  I noticed this happening since yesterday
(2002-07-18), and it persists after today's CVS update.

Example:

    Horizontal scrolling should redisplay to reflect the scrolling, but
    doesn't:

       Make a long line, e.g., by `C-u 200 x', and then turn on
       truncate-lines with `C-u 1 M-x toggle-truncate-lines RET';
       You are at the end of the long-line, so the screen is now
       scrolled horizontally to show the end.

       Move to the beginning of the line with `C-a', which should
       horizontally scroll to the left margin -- and notice that
       the screen doesn't change, the cursor just disappears.

       You can fix it with C-l.

-Miles
-- 
`Life is a boundless sea of bitterness'

Re: redisplay probs

[Tak Ota]

The following patch fixed at least the problem you reported however it
is quite useless since I still have other redisplay problems that I
cannot precisely characterize their conditions.  One thing seems to be
sure that if buffer_unchanged_p is set to 0 permanently all the
problem disappears.  Does buffer_unchanged_p worth introduction?

-Tak


*** ../../pure/emacs-21.3.50/src/xdisp.c	Fri Jul 19 07:15:41 2002
--- xdisp.c	Fri Jul 19 17:20:50 2002
***************
*** 10369,10375 ****
       not moved off the frame.  */
    if (buffer_unchanged_p
        && (rc = try_cursor_movement (window, startp, &temp_scroll_step),
! 	  rc != CURSOR_MOVEMENT_CANNOT_BE_USED))
      {
        switch (rc)
  	{
--- 10369,10376 ----
       not moved off the frame.  */
    if (buffer_unchanged_p
        && (rc = try_cursor_movement (window, startp, &temp_scroll_step),
! 	  rc != CURSOR_MOVEMENT_CANNOT_BE_USED)
!       && (XFASTINT (w->column_number_displayed) == (int) current_column ()))
      {
        switch (rc)
  	{


19 Jul 2002 09:59:30 +0900: Miles Bader <miles@lsi.nec.co.jp> wrote:

> Redisplay seems screwed up, such that it often fails to update the
> screen when it should.  I noticed this happening since yesterday
> (2002-07-18), and it persists after today's CVS update.
> 
> Example:
> 
>     Horizontal scrolling should redisplay to reflect the scrolling, but
>     doesn't:
> 
>        Make a long line, e.g., by `C-u 200 x', and then turn on
>        truncate-lines with `C-u 1 M-x toggle-truncate-lines RET';
>        You are at the end of the long-line, so the screen is now
>        scrolled horizontally to show the end.
> 
>        Move to the beginning of the line with `C-a', which should
>        horizontally scroll to the left margin -- and notice that
>        the screen doesn't change, the cursor just disappears.
> 
>        You can fix it with C-l.
> 
> -Miles
> -- 
> `Life is a boundless sea of bitterness'
> 
> _______________________________________________
> Emacs-devel mailing list
> Emacs-devel@gnu.org
> http://mail.gnu.org/mailman/listinfo/emacs-devel

Re: redisplay probs

[Richard Stallman]

I figured out the right fix for that problem.  Thanks.