Flickering mouse-face

Flickering mouse-face

[Nick Roberts]

I think that last change (2007-01-20) to mouse-face highlighting causes it to
flicker.  My guess would be that it gets repeatedly cleared in try_window.

To reproduce:

1) M-x gdb

2) Run gdb (like this): gdb --annotate=3 `yourprog'

 where yourprog is a simple C program that calls a procedure, yourproc say.

3) Type the GDB command "b yourproc" in the GUD buffer.

4) Type "run" in the GUD buffer.

5) If gdb-many-windows is nil, do M-x gdb-many-windows.

6) Click on `main' in the stack buffer to select that frame.  Notice the
   flickering highlighting.


I can't reproduce this elsewhere, so you could say my code is at fault, but it
didn't happen before the above change.

-- 
Nick                                           http://www.inet.net.nz/~nickrob

Re: Flickering mouse-face

[Stephen Berman]

On Mon, 22 Jan 2007 00:56:21 +1300 Nick Roberts <nickrob@snap.net.nz> wrote:

> I think that last change (2007-01-20) to mouse-face highlighting causes it to
> flicker.  My guess would be that it gets repeatedly cleared in try_window.

I can also reproduce this.  I didn't used the latest source but the
patched Emacs I built in connection with the thread "Bug in
incremental undrawing of mouseover highlighting", but that patch is
identical to the changed mentioned.  Moreover, I now have found that
the patch doesn't entirely fix the problem I reported (see my latest
followup in that thread), so a further or different patch is needed.

Steve Berman

Re: Flickering mouse-face

[Chong Yidong]

Stephen Berman <Stephen.Berman@gmx.net> writes:

> On Mon, 22 Jan 2007 00:56:21 +1300 Nick Roberts <nickrob@snap.net.nz> wrote:
>
>> I think that last change (2007-01-20) to mouse-face highlighting causes it to
>> flicker.  My guess would be that it gets repeatedly cleared in try_window.
>
> I can also reproduce this.  I didn't used the latest source but the
> patched Emacs I built in connection with the thread "Bug in
> incremental undrawing of mouseover highlighting", but that patch is
> identical to the changed mentioned.

I can't reproduce the bug using the recipe you suggested.  I checked
in a patch different to the one I posted on emacs-devel; could you
first see if the highlighting bug occurs with CVS Emacs?

Re: Flickering mouse-face

[Stephen Berman]

On Sun, 21 Jan 2007 16:05:08 -0500 Chong Yidong <cyd@stupidchicken.com> wrote:

> Stephen Berman <Stephen.Berman@gmx.net> writes:
>
>> On Mon, 22 Jan 2007 00:56:21 +1300 Nick Roberts <nickrob@snap.net.nz> wrote:
>>
>>> I think that last change (2007-01-20) to mouse-face highlighting
>>> causes it to flicker.  My guess would be that it gets repeatedly
>>> cleared in try_window.
>>
>> I can also reproduce this.  I didn't used the latest source but the
>> patched Emacs I built in connection with the thread "Bug in
>> incremental undrawing of mouseover highlighting", but that patch is
>> identical to the changed mentioned.
>
> I can't reproduce the bug using the recipe you suggested.  I checked
> in a patch different to the one I posted on emacs-devel; could you
> first see if the highlighting bug occurs with CVS Emacs?

Sorry for hastily jumping to a mistaken conclusion about the checked
in patch.  I assume you're referring to the latest recipe I posted in
the incremental undrawing thread.  Indeed, after updating to the
latest CVS sources, I haven't been able to reproduce the problem shown
with that recipe, nor with other experimenting.  And the massive
highlighting problem I had previously reported, which the patch you
posted had fixed, is also gone with your latest patch.  So AFAICS
you've fixed the undrawing/highlighting problem.  I guess the
flickering problem Nick Roberts reported, and the doubling of the MIME
part headers I mentioned in my first report in the other thread, both
of which I can still reproduce with the latest sources, require
different fixes.

Steve Berman

Re: Flickering mouse-face

[Chong Yidong]

OK, I've found and checked in the correct fix for the bug.  I also
reverted my original, deeply flawed fix.

FWIW, the original bug was caused by a 2006-09-17 change to dispnew.c
to avoid redrawing a whole row if it has mouse-face in it.  The
rationale for this change was that this was causing excessive
flickering of mode lines.  So I've made it so that we redraw a row if
it has mouse-face in it, except if it's a mode line.

Thanks for the feedback, and sorry for the false start in fixing this
bug.

Re: Flickering mouse-face

[Nick Roberts]

 > OK, I've found and checked in the correct fix for the bug.  I also
 > reverted my original, deeply flawed fix.

Looks good to me.

 > FWIW, the original bug was caused by a 2006-09-17 change to dispnew.c
 > to avoid redrawing a whole row if it has mouse-face in it.  The
 > rationale for this change was that this was causing excessive
 > flickering of mode lines.  So I've made it so that we redraw a row if
 > it has mouse-face in it, except if it's a mode line.
 > 
 > Thanks for the feedback, and sorry for the false start in fixing this
 > bug.

It amazes me that you can fix such a wide range of bugs at all.

-- 
Nick                                           http://www.inet.net.nz/~nickrob

Re: Flickering mouse-face

[Stephen Berman]

On Mon, 22 Jan 2007 12:49:14 +1300 Nick Roberts <nickrob@snap.net.nz> wrote:

>  > OK, I've found and checked in the correct fix for the bug.  I also
>  > reverted my original, deeply flawed fix.
>
> Looks good to me.

Me too.  So the only remaining bug in this constellation is the
doubling of the MIME headers, but I assume that's really a separate
problem, probably due to something particular to that article and I
would guess having to do with the fact that the entire attachment is
highlighted.  Strange, but probably not worth spending time on.

Steve Berman