From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.ciao.gmane.io!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: Emacs canvas support Date: Wed, 29 Apr 2020 22:03:00 +0300 Message-ID: <83ees6xggr.fsf@gnu.org> References: <834kt21yyo.fsf@gnu.org> <87zhau1uog.fsf@yahoo.com> <83sggmzjp8.fsf@gnu.org> <87mu6u1tii.fsf@yahoo.com> <83o8raziis.fsf@gnu.org> <877dxy1smz.fsf@yahoo.com> <87o8rae0ao.fsf@randomsample> <83lfmexmfp.fsf@gnu.org> <20200429171619.GB20842@tuxteam.de> <83imhixkva.fsf@gnu.org> <20200429185128.GA27164@tuxteam.de> Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="67473"; mail-complaints-to="usenet@ciao.gmane.io" Cc: emacs-devel@gnu.org To: tomas@tuxteam.de Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Apr 29 21:04:26 2020 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jTs0Q-000HRt-Fg for ged-emacs-devel@m.gmane-mx.org; Wed, 29 Apr 2020 21:04:26 +0200 Original-Received: from localhost ([::1]:60804 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jTs0P-00062o-Gy for ged-emacs-devel@m.gmane-mx.org; Wed, 29 Apr 2020 15:04:25 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:41160) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jTrzL-0005F8-Tp for emacs-devel@gnu.org; Wed, 29 Apr 2020 15:03:20 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:33188) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jTrzL-0007x3-Ex; Wed, 29 Apr 2020 15:03:19 -0400 Original-Received: from [176.228.60.248] (port=4842 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1jTrzK-0003pP-Bd; Wed, 29 Apr 2020 15:03:19 -0400 In-Reply-To: <20200429185128.GA27164@tuxteam.de> (tomas@tuxteam.de) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 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-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:248178 Archived-At: > Date: Wed, 29 Apr 2020 20:51:28 +0200 > From: tomas@tuxteam.de > Cc: emacs-devel@gnu.org > > > That's not how Emacs controls what's on display. It basically > > represents each window as a 2D array of glyphs, each one of which has > > a certain graphical representation. > > ...a display list of sorts. It's a far cry from any "list" in my book... > > The representation itself is of > > no concern to the display engine (well, almost); the only thing it > > cares about is the metrics of each glyph, because that's what it needs > > to do layout calculations. > > A graphical overlay wouldn't have "glyph metrics", the graphical > objects would (I think) have "absolute" [1] positions (possibly > precalculated by something else). The position is basically determined by the place in a buffer or a string where they were found. > I think the "interesting" problem is to know (quickly) which > graphical objects intersect the (visible) window -- something > graphics programs do as their main job. That's easy, we have infrastructure for that already -- it is used in expose_frame and its subroutines.