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Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw
From: |
Kenichi Handa |
Subject: |
Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw |
Date: |
Sat, 14 Apr 2007 10:48:55 +0900 |
User-agent: |
SEMI/1.14.3 (Ushinoya) FLIM/1.14.2 (Yagi-Nishiguchi) APEL/10.2 Emacs/22.0.95 (i686-pc-linux-gnu) MULE/5.0 (SAKAKI) |
In article <address@hidden>, Leo <address@hidden> writes:
> 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.
> 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.
Perhaps we must do something like this:
o When we open a font for a frame, check the ascents and
descents of ASCII characters (perhaps checking only "\|/"
is ok), and set font's ascent and descent to the maximum
of them if the font's data is shorter than glyphs' data.
---
Kenichi Handa
address@hidden
- [emacs-xft] Segmentation fault 0x081b3df2 in xftfont_draw, Leo, 2007/04/13
- Re: [emacs-xft] Segmentation fault 0x081b3df2 in xftfont_draw, Jan Djärv, 2007/04/13
- Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw, Leo, 2007/04/13
- Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw, Kenichi Handa, 2007/04/13
- Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw, Leo, 2007/04/13
- Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw,
Kenichi Handa <=
- Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw, Leo, 2007/04/14
- Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw, Leo, 2007/04/14
- Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw, Kenichi Handa, 2007/04/15
- Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw, Leo, 2007/04/14
- Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw, Kenichi Handa, 2007/04/17
- Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw, Leo, 2007/04/17
- Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw, Kenichi Handa, 2007/04/17