From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#67794: 30.0.50; mouse-face is not respected on SVG images Date: Wed, 13 Dec 2023 20:46:11 +0200 Message-ID: <835y12rle4.fsf@gnu.org> References: <87plzb7eek.fsf@ledu-giraud.fr> <83sf47tumh.fsf@gnu.org> <87jzpjo6pa.fsf@ledu-giraud.fr> <877cljnzuh.fsf@ledu-giraud.fr> <83cyvbtjnk.fsf@gnu.org> <87r0jqms5r.fsf@ledu-giraud.fr> <83o7eus3a4.fsf@gnu.org> <87bkauyyvf.fsf@ledu-giraud.fr> <83cyvarvgl.fsf@gnu.org> <87sf46ccmg.fsf@ledu-giraud.fr> <83a5qers00.fsf@gnu.org> <87zfye11z3.fsf@ledu-giraud.fr> <838r5yroyp.fsf@gnu.org> <87v8920xlb.fsf@ledu-giraud.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="40516"; mail-complaints-to="usenet@ciao.gmane.io" Cc: gerd.moellmann@gmail.com, 67794@debbugs.gnu.org, alan@idiocy.org To: Manuel Giraud Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Wed Dec 13 19:47:06 2023 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1rDUGA-000AJL-Ml for geb-bug-gnu-emacs@m.gmane-mx.org; Wed, 13 Dec 2023 19:47:06 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rDUFv-0000YZ-Qt; Wed, 13 Dec 2023 13:46:51 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rDUFr-0000Wa-3U for bug-gnu-emacs@gnu.org; Wed, 13 Dec 2023 13:46:49 -0500 Original-Received: from debbugs.gnu.org ([2001:470:142:5::43]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1rDUFq-0003S7-IC for bug-gnu-emacs@gnu.org; Wed, 13 Dec 2023 13:46:46 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1rDUG6-0006ux-3U for bug-gnu-emacs@gnu.org; Wed, 13 Dec 2023 13:47:02 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 13 Dec 2023 18:47:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 67794 X-GNU-PR-Package: emacs Original-Received: via spool by 67794-submit@debbugs.gnu.org id=B67794.170249320826572 (code B ref 67794); Wed, 13 Dec 2023 18:47:02 +0000 Original-Received: (at 67794) by debbugs.gnu.org; 13 Dec 2023 18:46:48 +0000 Original-Received: from localhost ([127.0.0.1]:59672 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1rDUFq-0006uS-QS for submit@debbugs.gnu.org; Wed, 13 Dec 2023 13:46:48 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:52196) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1rDUFl-0006uB-P6 for 67794@debbugs.gnu.org; Wed, 13 Dec 2023 13:46:45 -0500 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rDUFO-0003QT-61; Wed, 13 Dec 2023 13:46:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=MIME-version:References:Subject:In-Reply-To:To:From: Date; bh=wrVfDBZKJ5VyvgsE6FPJ4eI1/OhEchynESOIpO33jbc=; b=YofIk5Luo021SboAHlZN P9RuCeP5tNKysVpXY78wncfHax+ACugbRIrQvAFwSC3NiuKVGgO9YCn7yYmVmrynhmR8GX0EOnHV0 M+Ap4J1+BiPEL4inRXiDsEDEoxxNcIQxy5fztl+CbiNjOIxg+I/qH6hcVZccpNqYgRK42Ri7m9fOQ qwp0LU7GxWbEETdi61U7MyjsMJLQGcwvf/b6KOUwRJugEsgpN0D+gAoH5+g7gSMeF9Fb1b7yFaIL7 Kd2Nmh1MHBsBMuUJJI7wSCdyA9elsl7W+tYqbflNi7ZiOpnnaMan3cR2A1FdIr3S+kIgd1kvbhj9D rsqsg/Rv7d1Klw==; In-Reply-To: <87v8920xlb.fsf@ledu-giraud.fr> (message from Manuel Giraud on Wed, 13 Dec 2023 19:24:48 +0100) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.bugs:276153 Archived-At: > From: Manuel Giraud > Cc: Gerd Möllmann , > alan@idiocy.org, > 67794@debbugs.gnu.org > Date: Wed, 13 Dec 2023 19:24:48 +0100 > > Eli Zaretskii writes: > > >> From: Manuel Giraud > >> Cc: alan@idiocy.org, 67794@debbugs.gnu.org > >> Date: Wed, 13 Dec 2023 17:50:08 +0100 > >> > >> BTW, do you know why mouse-highlight is this way? Is it because it > >> was an afterthought of the display engine or is it because of > >> performance issues or…? > > > > How would you design it instead? > > > > I'm not saying that what we have is the only possible design, but I'm > > curious what alternative design ideas could be used. > > Sorry I do not have an alternative design idea 😅. It's just that from > my, obviously limited, point of view the Emacs display engine is a work > horse that could handled many cases regarding how to display glyphs and > I was wondering why it was not used for mouse highlight also. We do use the display engine, just the last part of its processing: the drawing of glyphs on the glass. > > Btw, AFAIU the person who at the time decided how this will work is > > here: it's Gerd (CC'ed). Maybe he can share his memories about why he > > ended up with this design. > > Thanks for summoning Gerd. I have an answer now even though I do not > have the knowledge to understand it fully. What Gerd says, in a nutshell, is that since this code was running from a signal handler, there was a basic requirement to do it as simple as possible, and in particular not to do anything that would mean memory allocation, since memory allocation functions (and many other functions) in a typical libc were non-reentrant back then. So the chosen design was one that reused existing data structures as much as possible.