From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: [Patch]: Allow overlay arrows to be inserted before the text at column zero rather than splatting it. Date: Mon, 19 Aug 2019 05:30:24 -0400 Message-ID: References: <20190818134804.GA31509@ACM> <83mug6mtjy.fsf@gnu.org> <20190818161530.GB31509@ACM> <83imqumo7i.fsf@gnu.org> <20190818184356.GC31509@ACM> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="103618"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) Cc: Eli Zaretskii , emacs-devel@gnu.org To: Alan Mackenzie Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Aug 19 11:33:04 2019 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hze29-000Qim-1F for ged-emacs-devel@m.gmane.org; Mon, 19 Aug 2019 11:33:01 +0200 Original-Received: from localhost ([::1]:46596 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1hze26-0000Ri-6n for ged-emacs-devel@m.gmane.org; Mon, 19 Aug 2019 05:32:58 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:33051) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1hze1N-0000Nv-Qs for emacs-devel@gnu.org; Mon, 19 Aug 2019 05:32:14 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hze1J-0006Hz-Hg for emacs-devel@gnu.org; Mon, 19 Aug 2019 05:32:12 -0400 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:28722) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hzdzk-0005UJ-7C; Mon, 19 Aug 2019 05:32:05 -0400 Original-Received: from pmg2.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id AD19B810A3; Mon, 19 Aug 2019 05:30:29 -0400 (EDT) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 0395D81098; Mon, 19 Aug 2019 05:30:28 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1566207028; bh=lNVsO4y1/ulaOppkFwmIQEqNZxpjMbsnGmUFzokObbE=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=YUvU4OzoJfkGK60jNFxblVPlA2sCTjtJXdPstsYrfx8AflPsIaanVx0Dk8dDl/+yZ /JIb1Ju7NWYJ7HVPGthHQHN9iS2NWjJCjSDpnLPAnmUQtFNFbeRBmLEHJZw5j4pS5I tZtS58NkLQOWsJijOmcljM+VN/RhNMNQm9McX5pODps65tMQdCpQhq92xd3reM3dtd kBgxrADyPEV1DRM1UKtt0CDNFOG+FoUsW5t4MocoL4ScAbetzK5RlGhAlcpIt217OX cpThAKxW8ewH8PrdzPdnnwRzIR0gQrshbGvj3POYaPyRJPHIvvUoM0/Sr86CAwzGCp 0XMpGXRYFn74g== Original-Received: from alfajor (port-87-193-132-138.static.qsc.de [87.193.132.138]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 495AF1202D5; Mon, 19 Aug 2019 05:30:27 -0400 (EDT) In-Reply-To: <20190818184356.GC31509@ACM> (Alan Mackenzie's message of "Sun, 18 Aug 2019 18:43:56 +0000") X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 132.204.25.50 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.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:239456 Archived-At: >> I think it's a general consensus that the "overlay arrow" feature >> should be walked away of, and at some point should be deprecated. >> I'd prefer not to base new code on that kludge. I didn't know there's a consensus around that, but I'm happy to hear it and I'm definitely in agreement with that consensus. > I don't think there's anything else in Emacs at the moment that could > take its place. Strictly speaking, you can kludge something with a mix of `display` and `after-string` properties, but it'd likely be fiddly. > The essence here is being able to insert "=>" onto the > display _without_ disturbing the horizontal alignment, as needed by > debuggers. Maybe, in addition to before-strings and after-strings we > need "overlay-strings" (with a better name than that), which would cover > up the underlying text. Indeed. Tho, IMO the implementation shouldn't be done in the glyph matrix but in an additional layer drawn on top of the rending of the glyph matrix (this way it can work even when the "hidden" text uses proportional fonts, or a different size, or an image, ...). Stefan