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. I will try a font that cause flickering and see if I can catch a bug. > >> 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. I can confirm this. Do you think that's a bug in dejavu sans mono? > > 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. regards, -- Leo <sdl.web AT gmail.com> (GPG Key: 9283AA3F) _______________________________________________ emacs-pretest-bug mailing list [EMAIL PROTECTED] http://lists.gnu.org/mailman/listinfo/emacs-pretest-bug
