From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: alpha support for colors Date: Wed, 31 Oct 2012 06:00:07 +0200 Message-ID: <83ip9r70l4.fsf@gnu.org> References: <87wqy8n2tk.fsf@gnu.org> <83objj7t21.fsf@gnu.org> <87lienjsz0.fsf@uwakimon.sk.tsukuba.ac.jp> Reply-To: Eli Zaretskii NNTP-Posting-Host: plane.gmane.org X-Trace: ger.gmane.org 1351656021 3069 80.91.229.3 (31 Oct 2012 04:00:21 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 31 Oct 2012 04:00:21 +0000 (UTC) Cc: aaditya@sood.net.in, emacs-devel@gnu.org To: "Stephen J. Turnbull" Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Oct 31 05:00:30 2012 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 1TTPTf-0003HX-JV for ged-emacs-devel@m.gmane.org; Wed, 31 Oct 2012 05:00:27 +0100 Original-Received: from localhost ([::1]:57337 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TTPTX-0006YN-2R for ged-emacs-devel@m.gmane.org; Wed, 31 Oct 2012 00:00:19 -0400 Original-Received: from eggs.gnu.org ([208.118.235.92]:36763) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TTPTR-0006Xt-2h for emacs-devel@gnu.org; Wed, 31 Oct 2012 00:00:17 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TTPTL-0004Vl-SV for emacs-devel@gnu.org; Wed, 31 Oct 2012 00:00:13 -0400 Original-Received: from mtaout22.012.net.il ([80.179.55.172]:44287) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TTPTL-0004HV-KW for emacs-devel@gnu.org; Wed, 31 Oct 2012 00:00:07 -0400 Original-Received: from conversion-daemon.a-mtaout22.012.net.il by a-mtaout22.012.net.il (HyperSendmail v2007.08) id <0MCQ00900OER1200@a-mtaout22.012.net.il> for emacs-devel@gnu.org; Wed, 31 Oct 2012 05:59:52 +0200 (IST) Original-Received: from HOME-C4E4A596F7 ([87.69.4.28]) by a-mtaout22.012.net.il (HyperSendmail v2007.08) with ESMTPA id <0MCQ008J4OFSL9A0@a-mtaout22.012.net.il>; Wed, 31 Oct 2012 05:59:52 +0200 (IST) In-reply-to: <87lienjsz0.fsf@uwakimon.sk.tsukuba.ac.jp> X-012-Sender: halo1@inter.net.il X-detected-operating-system: by eggs.gnu.org: Solaris 10 (beta) X-Received-From: 80.179.55.172 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:154597 Archived-At: > From: "Stephen J. Turnbull" > Cc: aaditya sood , > emacs-devel@gnu.org > Date: Wed, 31 Oct 2012 11:06:11 +0900 > > Eli Zaretskii writes: > > > What do you mean by "composition of all the faces"? Why "all"? > > I suspect aaditya is thinking in terms of bitmap composition > operations on graphics layers, not Emacs faces. Maybe. I just don't understand clearly enough what exactly was the intent. As you know, Emacs doesn't operate on the bitmap level, except very low in the terminal-specific code. At that level, there are no faces anymore, just colors and other graphics-related stuff. > So he'd like to put an overlay on some text, give that overlay a 'face > property of '(+ red), and turn all the blue text in the overlay to > violet (the RGB sum of #F00 and #00F == #F0F). Maybe I don't get something, but (a) this _is_ about faces and their combination, '(+ red) being a kind of "syntactic sugar"; and (b) all it needs is the ability to combine colors when merging faces, instead of just selecting one color of the two. By contrast, alpha-blending, AFAIU, is about transparency, not about combining any 2 colors. So I'm probably still missing something.