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: Image transformations Date: Tue, 25 Jun 2019 10:43:22 -0400 Message-ID: References: <20190613165804.GB11266@breton.holly.idiocy.org> <83d0jhz9za.fsf@gnu.org> <20190613192724.GA11945@breton.holly.idiocy.org> <83zhmlxo6d.fsf@gnu.org> <20190613222626.GA12971@breton.holly.idiocy.org> <83o930y7cl.fsf@gnu.org> <20190615104242.GA13368@breton.holly.idiocy.org> <838su3w0de.fsf@gnu.org> <20190616152259.GA22789@breton.holly.idiocy.org> <83d0jdv68i.fsf@gnu.org> <20190617211332.GA55597@breton.holly.idiocy.org> <83a7e6na26.fsf@gnu.org> <8336jymm0g.fsf@gnu.org> <95554A73-A5B5-4407-A5B4-4F901FF5E6CF@gnu.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="113493"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) Cc: emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Jun 25 16:55:48 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 1hfmrL-000TJQ-1E for ged-emacs-devel@m.gmane.org; Tue, 25 Jun 2019 16:55:47 +0200 Original-Received: from localhost ([::1]:32826 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hfmrK-0001TP-0j for ged-emacs-devel@m.gmane.org; Tue, 25 Jun 2019 10:55:46 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:49462) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hfmft-0003i7-8X for emacs-devel@gnu.org; Tue, 25 Jun 2019 10:43:58 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hfmfr-0004Rk-5v for emacs-devel@gnu.org; Tue, 25 Jun 2019 10:43:57 -0400 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:27919) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hfmfW-000444-1N; Tue, 25 Jun 2019 10:43:35 -0400 Original-Received: from pmg2.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 4B2E581151; Tue, 25 Jun 2019 10:43:27 -0400 (EDT) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id EECBA8030C; Tue, 25 Jun 2019 10:43:24 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1561473805; bh=/VGR+X85YRqtnkqbSyWpkZ5bgEbWdPX87nKpemx4EGk=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=pWlD1dsiSNeo8YIX9fUXUDG3YR7Mkh4iPBNlNpPNxlrch9MeFZh9Ho03ckmf8xf+m n8o4KBz8NW2CSYjEzomAijFzVCmCYbcs3g8WjTTvJxCRfuER8tXJrxul2Y+hFEDpY1 DDnyLWQolp2AkYpDjGwNx1ptSrR37ZcsRlCHt7bgNUbOuUTscWi3I/QM+t364KiLiX px8IuLvY8KUJtDsj21pKkWpd73fEr4y30qH88zJUFK31b5RaJApLMKm83XXzL9t110 paSJYe5DaGezT9o0yNT6iyCeTyqIMsggmyyzvR311xTU3By7YRHfDhqrBnr/rTcrik U2/4tSpu7Y/VQ== Original-Received: from pastel (69-196-134-84.dsl.teksavvy.com [69.196.134.84]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 49E47120C5F; Tue, 25 Jun 2019 10:43:24 -0400 (EDT) In-Reply-To: <95554A73-A5B5-4407-A5B4-4F901FF5E6CF@gnu.org> (Eli Zaretskii's message of "Tue, 25 Jun 2019 07:34:10 +0300") 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:238136 Archived-At: >> Part of the reason for my question above is to figure out if the >> implementation of the API is likely to have such matrix inversion >> code internally > How can we possibly know for sure, on all supported platforms? I'm not looking for "know for sure", just for a general understanding of how things usually work. >> (since it seems quite possible that sometimes one is >> preferable and sometimes the other). > I admit I don't see why we would have different preferences. I'm asking about the other side of the API, i.e. not us but the implementors of Cairo, etc... It's really just out of curiosity, not directly related to what our code should do: does the "inverse matrix" indicate that the Windows guys use "fundamentally" different algorithms than the Cairo guys, or just that inverting the matrix is considered "par for the course" because sometimes you need one and sometimes you need the other. Stefan