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: image scaling Date: Fri, 22 Feb 2008 15:38:27 -0500 Message-ID: <87fxvkk9q4.fsf@stupidchicken.com> References: <87odaam9oy.fsf@stupidchicken.com> <8563wiaskc.fsf@lola.goethe.zz> <87lk5dr3kf.fsf@stupidchicken.com> <87r6f5dzvm.fsf@ambire.localdomain> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1203712807 20593 80.91.229.12 (22 Feb 2008 20:40:07 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 22 Feb 2008 20:40:07 +0000 (UTC) Cc: Thien-Thi Nguyen , emacs-devel@gnu.org To: "Juanma Barranquero" Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Feb 22 21:40:32 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 1JSegy-0006Vy-NL for ged-emacs-devel@m.gmane.org; Fri, 22 Feb 2008 21:40:25 +0100 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1JSegT-00086J-B1 for ged-emacs-devel@m.gmane.org; Fri, 22 Feb 2008 15:39:53 -0500 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1JSegP-000848-TF for emacs-devel@gnu.org; Fri, 22 Feb 2008 15:39:49 -0500 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1JSegP-00082t-2X for emacs-devel@gnu.org; Fri, 22 Feb 2008 15:39:49 -0500 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1JSegO-00082W-So for emacs-devel@gnu.org; Fri, 22 Feb 2008 15:39:48 -0500 Original-Received: from cyd.mit.edu ([18.115.2.24]) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1JSegO-0000xE-Ia for emacs-devel@gnu.org; Fri, 22 Feb 2008 15:39:48 -0500 Original-Received: by cyd.mit.edu (Postfix, from userid 1000) id 8924C4E3FB; Fri, 22 Feb 2008 15:38:27 -0500 (EST) In-Reply-To: (Juanma Barranquero's message of "Fri\, 22 Feb 2008 12\:06\:04 +0100") User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.1.91 (gnu/linux) X-detected-kernel: by monty-python.gnu.org: Linux 2.6 (newer, 2) 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:90017 Archived-At: "Juanma Barranquero" writes: >> Maybe the scaling is part of a series of operations, >> the end of which would be displayable but not the middle. > > I'm not sure I understand. A series of operations (presumably, image > transformations of some sort) without the image library support? We do > that today, manipulating for example PNG images without (statically or > dynamically) linking libpng? Suppose, for example, we "outsource" image transformations to a specific external library. For the sake of argument, let's say this library is libpng. One way to do this is to have Emacs use libpng internally to store and manipulate (e.g. rescale) images, instead of the pixel buffer system we currently use. Alternatively, Emacs might keep the pixel buffer system, but perform image manipulations by converting the image into a png internally, calling the relevant libpng function to rescale it or whatever, and then converting it back. We would thus be using libpng to perform image manipulations, for arbitrary images and not just pngs. The trouble is that if libpng is not available, all this functionality would disappear (not just for pngs, but also for gifs or whatever other images *are* supported). In that case, how would we handle this at the Lisp interface level?