From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Chong Yidong Newsgroups: gmane.emacs.devel Subject: Re: Emacs and Gnome Canvas Date: Thu, 15 Jul 2010 12:00:05 -0400 Message-ID: <877hkwag6y.fsf@stupidchicken.com> References: <4C3CD120.4040905@swipnet.se> <5A91499A-0470-43FD-9F48-560CEAD3424C@mit.edu> <83wrsyr068.fsf@gnu.org> <83iq4hhjww.fsf@gnu.org> <87sk3lbvv0.fsf@telefonica.net> <83hbk1grnq.fsf@gnu.org> <4C3EBCDC.8050709@swipnet.se> <83d3upgmwj.fsf@gnu.org> <4C3ECB4C.6050208@swipnet.se> <83aaptgly1.fsf@gnu.org> <4C3ED4F9.4080603@swipnet.se> <83630hgi0r.fsf@gnu.org> <4C3EE8D6.3020607@swipnet.se> <8339vlgcax.fsf@gnu.org> <87fwzkbzg8.fsf@telefonica.net> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Trace: dough.gmane.org 1279209737 19967 80.91.229.12 (15 Jul 2010 16:02:17 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Thu, 15 Jul 2010 16:02:17 +0000 (UTC) Cc: emacs-devel@gnu.org To: =?utf-8?Q?=C3=93scar?= Fuentes Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Jul 15 18:02:14 2010 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1OZQt0-000653-TP for ged-emacs-devel@m.gmane.org; Thu, 15 Jul 2010 18:02:12 +0200 Original-Received: from localhost ([127.0.0.1]:60743 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OZQsy-00076E-TC for ged-emacs-devel@m.gmane.org; Thu, 15 Jul 2010 12:02:09 -0400 Original-Received: from [140.186.70.92] (port=53535 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OZQrD-0006NX-NR for emacs-devel@gnu.org; Thu, 15 Jul 2010 12:00:24 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OZQr3-00020y-1x for emacs-devel@gnu.org; Thu, 15 Jul 2010 12:00:19 -0400 Original-Received: from pantheon-po14.its.yale.edu ([130.132.50.23]:41445) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OZQr3-00020g-0G for emacs-devel@gnu.org; Thu, 15 Jul 2010 12:00:09 -0400 Original-Received: from furry (dhcp128036014221.central.yale.edu [128.36.14.221]) (authenticated bits=0) by pantheon-po14.its.yale.edu (8.12.11.20060308/8.12.11) with ESMTP id o6FG07tl029146 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Thu, 15 Jul 2010 12:00:07 -0400 Original-Received: by furry (Postfix, from userid 1000) id F21EEC013; Thu, 15 Jul 2010 12:00:06 -0400 (EDT) In-Reply-To: <87fwzkbzg8.fsf@telefonica.net> (=?utf-8?Q?=22=C3=93scar?= Fuentes"'s message of "Thu, 15 Jul 2010 16:18:47 +0200") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.50 (gnu/linux) X-YaleITSMailFilter: Version 1.2c (attachment(s) not renamed) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4-2.6 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:127373 Archived-At: =C3=93scar Fuentes writes: > AFAIK the display system have evolved from the tty one by incremental > updates No, the redisplay system was redesigned during Emacs 21 specifically with both tty and graphical terminals in mind. It did not evolve mindlessly; the design has a very specific logic behind it. As long as we support tty, there is no getting rid of the redisplay iterator. Since we have the redisplay iterator, the same system might as well be used for graphical displays; it would terribly problematic to switch between completely different rendering schemes for tty and graphical displays to render the same underlying content. It is still not too clear to me what we would gain from a Canvas-type revamp of redisplay, relative to the large costs involved. It does not seem like a promising avenue of development. A more promising route is the one that Yamamoto Mitsuharu has explored, mentioned earlier in this thread, which (IIUC) treats Cairo as a graphical terminal to render onto, on the same footing as the tty/X/Windows/NS terminals. Here, I can see a reasonable path to real improvement. For example, it might allow us to use the GTK printing infrastructure, which operates on Cairo contexts. If you are interested in redisplay development, that is the direction I'd suggest looking into.