From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Image rescaling Date: Mon, 15 Sep 2014 10:27:42 -0400 Message-ID: References: NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1410791325 8792 80.91.229.3 (15 Sep 2014 14:28:45 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 15 Sep 2014 14:28:45 +0000 (UTC) Cc: joakim@verona.se, emacs-devel@gnu.org To: Lars Magne Ingebrigtsen Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Sep 15 16:28:39 2014 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XTXGd-0007vr-22 for ged-emacs-devel@m.gmane.org; Mon, 15 Sep 2014 16:28:35 +0200 Original-Received: from localhost ([::1]:60123 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XTXGc-0007wK-FD for ged-emacs-devel@m.gmane.org; Mon, 15 Sep 2014 10:28:34 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:43211) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XTXGI-0007v8-PD for emacs-devel@gnu.org; Mon, 15 Sep 2014 10:28:21 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XTXGB-0003sF-Ox for emacs-devel@gnu.org; Mon, 15 Sep 2014 10:28:14 -0400 Original-Received: from mercure.iro.umontreal.ca ([132.204.24.67]:46282) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XTXGB-0003s5-Kw for emacs-devel@gnu.org; Mon, 15 Sep 2014 10:28:07 -0400 Original-Received: from hidalgo.iro.umontreal.ca (hidalgo.iro.umontreal.ca [132.204.27.50]) by mercure.iro.umontreal.ca (Postfix) with ESMTP id 3A3F484F6E; Mon, 15 Sep 2014 10:28:07 -0400 (EDT) Original-Received: from lechon.iro.umontreal.ca (lechon.iro.umontreal.ca [132.204.27.242]) by hidalgo.iro.umontreal.ca (Postfix) with ESMTP id 1FEB81E5B74; Mon, 15 Sep 2014 10:27:43 -0400 (EDT) Original-Received: by lechon.iro.umontreal.ca (Postfix, from userid 20848) id D36ADB42B3; Mon, 15 Sep 2014 10:27:42 -0400 (EDT) In-Reply-To: (Lars Magne Ingebrigtsen's message of "Mon, 15 Sep 2014 15:03:33 +0200") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4.50 (gnu/linux) X-DIRO-MailScanner-Information: Please contact the ISP for more information X-DIRO-MailScanner: Found to be clean X-DIRO-MailScanner-SpamCheck: n'est pas un polluriel, SpamAssassin (score=-2.82, requis 5, autolearn=not spam, ALL_TRUSTED -2.82, MC_TSTLAST 0.00) X-DIRO-MailScanner-From: monnier@iro.umontreal.ca X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 132.204.24.67 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:174324 Archived-At: > Rescaling is apparently a pretty tricky thing that is mostly implemented > wrong: > http://www.4p8.com/eric.brasseur/gamma.html Rescaling an image is exactly the same problem as resampling an audio file (e.g. to play it at 48KHz instead of the 44.1KHz used on the CD from which it came). Doing it naively works, but in some cases gives very poor results, indeed. Stefan