Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw

[Leo]

Dear Kenichi,

----- Kenichi Handa (2007-04-14) wrote:-----

>> It happens usually when there are many links in a buffer such as in ERC
>> or W3M. I can move around mouse in a w3m buffer with tons of links (such
>> as www.6park.com) to catch a crash, which usually happens within a few
>> minutes. I just catch one with 'emacs -Q'. Unfortunately I don't know
>> the exact recipe to trigger a crash.
>
> I've just installed w3m and emacs-w3m, visited
> www.6park.com, moved mouse-cursor and normal cursor onto
> various links, but couldn't trigger a crash.

Since that website is using Chinese font and the flickering problem
depends on font and size, I wonder if that is why you can not reproduce
the crash. But I can confirm even with a font that *does not* cause
flickering, crashes still happen. So seems there is something wrong.

BTW, I am using CVS emacs-w3m.

>> The following can help you see the bug although it won't crash Emacs:
>
>>          o  emacs -Q --enable-font-backend -fn SOMEFONT
>>          o  C-u 3 2 M-x hanoi
>
>> You should see the frame flickering like TV disturbed by static.
>
> I can confirm the flickering with some fonts of some size.
> For instance, this cause flickering:
>
> emacs-unicode --enable-font-backend -fn 'dejavu sans mono:pixelsize=16'
>
> but these don't cause flickering:
>
> emacs-unicode --enable-font-backend -fn 'dejavu sans mono:pixelsize=24'
> emacs-unicode --enable-font-backend -fn 'lucidatypewriter:pixelsize=16'
>
> I think the reason is that font-height of "dejavu sans
> mono:pixelsize=16" is somehow shorter than the glyph '|' in
> that font.  So, every time Emacs redraw '|', the upper and
> lower lines are also redrawn which leads to the whole buffer
> redrawing.  For instance, when I replace all occurence of
> "?\|" in lisp/play/hanoi.el with "?i", even this:
>
> emacs-unicode --enable-font-backend -fn 'dejavu sans mono:pixelsize=16'
>
> stops flickering.

Indeed, using another font can stop flickering in hanoi. But flickering
can still be seen by doing the following in emacs-w3m:

        1.  go to http://dir.gmane.org/gmane.education.brazil.infoestacio

        2.  In Line 10, there is "All messages from the list, with
            excerpted texts.", now move mouse cursor back and forth on
            that link and you will see the same phenomena as in hanoi.

The font I am using is:

,----
| dejavu lgc sans 
mono:pixelsize=17:foundry=unknown:weight=bold:slant=r:width=normal (#x24)
`----

HTH
-- 
Leo <sdl.web AT gmail.com>                         (GPG Key: 9283AA3F)