From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: David Kastrup Newsgroups: gmane.emacs.devel Subject: Re: image scaling Date: Fri, 22 Feb 2008 22:52:13 +0100 Message-ID: <85myps8xrm.fsf@lola.goethe.zz> References: <87odaam9oy.fsf@stupidchicken.com> <8563wiaskc.fsf@lola.goethe.zz> <87lk5dr3kf.fsf@stupidchicken.com> <85wsox8m9t.fsf@lola.goethe.zz> <87mypska6r.fsf@stupidchicken.com> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1203717199 3898 80.91.229.12 (22 Feb 2008 21:53:19 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 22 Feb 2008 21:53:19 +0000 (UTC) Cc: Stefan Monnier , emacs-devel@gnu.org To: Chong Yidong Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Feb 22 22:53:44 2008 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 4.50) id 1JSfps-0001F6-2D for ged-emacs-devel@m.gmane.org; Fri, 22 Feb 2008 22:53:40 +0100 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1JSfpM-0002la-Qp for ged-emacs-devel@m.gmane.org; Fri, 22 Feb 2008 16:53:08 -0500 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1JSfoa-0002RN-TS for emacs-devel@gnu.org; Fri, 22 Feb 2008 16:52:20 -0500 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1JSfoZ-0002Qg-5K for emacs-devel@gnu.org; Fri, 22 Feb 2008 16:52:20 -0500 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1JSfoY-0002QX-PM for emacs-devel@gnu.org; Fri, 22 Feb 2008 16:52:18 -0500 Original-Received: from mail-in-17.arcor-online.net ([151.189.21.57]) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1JSfoY-0005Bq-Gz for emacs-devel@gnu.org; Fri, 22 Feb 2008 16:52:18 -0500 Original-Received: from mail-in-12-z2.arcor-online.net (mail-in-12-z2.arcor-online.net [151.189.8.29]) by mail-in-17.arcor-online.net (Postfix) with ESMTP id 9959D2BB6FD; Fri, 22 Feb 2008 22:52:16 +0100 (CET) Original-Received: from mail-in-03.arcor-online.net (mail-in-03.arcor-online.net [151.189.21.43]) by mail-in-12-z2.arcor-online.net (Postfix) with ESMTP id 83732279436; Fri, 22 Feb 2008 22:52:16 +0100 (CET) Original-Received: from lola.goethe.zz (dslb-084-061-017-215.pools.arcor-ip.net [84.61.17.215]) by mail-in-03.arcor-online.net (Postfix) with ESMTP id 3C12B30AC3A; Fri, 22 Feb 2008 22:52:16 +0100 (CET) Original-Received: by lola.goethe.zz (Postfix, from userid 1002) id A67ED1CDB1E6; Fri, 22 Feb 2008 22:52:14 +0100 (CET) In-Reply-To: <87mypska6r.fsf@stupidchicken.com> (Chong Yidong's message of "Fri, 22 Feb 2008 15:28:28 -0500") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.60 (gnu/linux) X-Virus-Scanned: ClamAV 0.92.1/5939/Fri Feb 22 21:30:08 2008 on mail-in-03.arcor-online.net X-Virus-Status: Clean X-detected-kernel: by monty-python.gnu.org: 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:90022 Archived-At: Chong Yidong writes: > David Kastrup writes: > >>> but it's simple enough to understand and work on; and I don't know of >>> any performance problem in the way Emacs handles image pixmaps. >> >> You must be kidding. We have an image cache exactly because Emacs can't >> handle images close to reasonably efficiently. > > Don't other programs use caches for images? XEmacs, for example, does not have the equivalent, and works fine (actually quite faster than Emacs) when using preview-latex. The point is that when the image data is loaded into memory, Emacs still can't display it fast. It converts it with a painfully slow conversion chain called for every pixel into a pixmap and caches that. Considering that the binary data is pretty much identical a pixmap to start with (maybe modulo a gamma correction lookup table), this is somewhat ridiculous. The code paths are so muddled, however, that it is not easy to rip this out. Have you actually looked at the code? -- David Kastrup, Kriemhildstr. 15, 44793 Bochum