From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Alan Third Newsgroups: gmane.emacs.bugs Subject: bug#47040: 27.1; PNG binary transparency is ignored Date: Wed, 10 Mar 2021 22:14:25 +0000 Message-ID: References: <86o8fr1e3d.fsf@gmail.com> <87czw7jbgq.fsf@gnus.org> <83tupjniri.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="19594"; mail-complaints-to="usenet@ciao.gmane.io" Cc: Lars Ingebrigtsen , ynyaaa@gmail.com, 47040@debbugs.gnu.org To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Wed Mar 10 23:26:18 2021 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 1lK7HV-0004wU-AV for geb-bug-gnu-emacs@m.gmane-mx.org; 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h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nthggrYyEzjNrknU2PJACgUWyyqgsT7VbsEjuz1wobJUTRBzeOv9aGTuWzpTku3x8 Rnx3H9x3WPNyXzm4JxbRU6Vmi/qKmba8Ze1MbMHMvpDToL2HkNF0JpFs5zdAQM/j+x qe0YylJf/7jUCKbhkiuh+ZCjRDo7PewTWiWhGykWhN3mECpdtJIK3cYsLhixDTRTSW clyV86buyLyeG8h2QAc+tTX8uPf10lyDC02cWHq0UN5A1JqL7eV1eBVQPc3kWbXjGj cR7RB6LT4wZEisZ2LIjFY2e0As8RClVK631gKb/ygM1M2b5TkSlrvZW0g0Lo43cV9M UF3+k08Ly9+jQ== Original-Received: by breton.holly.idiocy.org (Postfix, from userid 501) id 45300202AE43BA; Wed, 10 Mar 2021 22:14:25 +0000 (GMT) Mail-Followup-To: Alan Third , Eli Zaretskii , Lars Ingebrigtsen , ynyaaa@gmail.com, 47040@debbugs.gnu.org Content-Disposition: inline In-Reply-To: <83tupjniri.fsf@gnu.org> 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" Xref: news.gmane.io gmane.emacs.bugs:202043 Archived-At: On Wed, Mar 10, 2021 at 05:14:09PM +0200, Eli Zaretskii wrote: > > From: Lars Ingebrigtsen > > Date: Wed, 10 Mar 2021 16:05:25 +0100 > > Cc: 47040@debbugs.gnu.org > > > > > Red pixels in the both images have 0 for alpha value, so they should be > > > transparent and invisible, but transparent1.png is displayed as a red > > > square with a green frame in a emacs buffer. > > > > > > transparent2.png is displayed as a white square with a green frame as > > > expected. > > > > > > When they are displayed in a chrome browser, inner squares of the both > > > images are displayed as transparent. > > > > I'm unable to reproduce this in Emacs 27.1 in Debian/bullseye, so this > > may be a Windows-specific problem. It may also be fixed in Emacs 28, > > since the transparency code has gotten a lot of work. Would it be > > possible for you to check in Emacs 28 whether this problem is still > > present there? > > > > If not, can somebody else with Windows and Emacs 28 check whether the > > problem is still present? > > The problem is still present when using the default libpng, but not if > I use the w32 native image API. I see the same on NS, so it must be something wrong with the libpng support code. Although I don't know why Lars doesn't see it on Debian. I wonder if it's related to image.c:6909 # ifdef PNG_tRNS_SUPPORTED It looks like that is not defined here... I don't really understand what the png code is doing with transparency. -- Alan Third