From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from re-prd-fep-042.btinternet.com (mailomta32-re.btinternet.com [213.120.69.125]) by sourceware.org (Postfix) with ESMTPS id E7A1D3857C4C for ; Mon, 24 Jan 2022 15:02:45 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org E7A1D3857C4C Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=dronecode.org.uk Authentication-Results: sourceware.org; spf=none smtp.mailfrom=dronecode.org.uk Received: from re-prd-rgout-003.btmx-prd.synchronoss.net ([10.2.54.6]) by re-prd-fep-042.btinternet.com with ESMTP id <20220124150244.MRVN12369.re-prd-fep-042.btinternet.com@re-prd-rgout-003.btmx-prd.synchronoss.net>; Mon, 24 Jan 2022 15:02:44 +0000 Authentication-Results: btinternet.com; auth=pass (PLAIN) smtp.auth=jonturney@btinternet.com; bimi=skipped X-SNCR-Rigid: 61A69BAC05F90B20 X-Originating-IP: [81.129.146.209] X-OWM-Source-IP: 81.129.146.209 (GB) X-OWM-Env-Sender: jonturney@btinternet.com X-VadeSecure-score: verdict=clean score=0/300, class=clean X-RazorGate-Vade: gggruggvucftvghtrhhoucdtuddrgedvvddrvdeigdejfecutefuodetggdotefrodftvfcurfhrohhfihhlvgemuceutffkvffkuffjvffgnffgvefqofdpqfgfvfenuceurghilhhouhhtmecufedtudenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhepkfffgggfuffvfhfhjggtgfesthekredttdefjeenucfhrhhomheplfhonhcuvfhurhhnvgihuceojhhonhdrthhurhhnvgihsegurhhonhgvtghouggvrdhorhhgrdhukheqnecuggftrfgrthhtvghrnhepleeftdejvdefffejveefgeehgeekieeljeekvdekjefgfeelieehlefftefhgedvnecuffhomhgrihhnpehfrhgvvgguvghskhhtohhprdhorhhgnecukfhppeekuddruddvledrudegiedrvddtleenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhephhgvlhhopegludelvddrudeikedruddruddtfegnpdhinhgvthepkedurdduvdelrddugeeirddvtdelpdhmrghilhhfrhhomhepjhhonhdrthhurhhnvgihsegurhhonhgvtghouggvrdhorhhgrdhukhdpnhgspghrtghpthhtohepvddprhgtphhtthhopefmvghnhghhihhtvghsvghllhestghomhgtrghsthdrnhgvthdprhgtphhtthhopegthihgfihinhestgihghifihhnrdgtohhm X-RazorGate-Vade-Verdict: clean 0 X-RazorGate-Vade-Classification: clean Received: from [192.168.1.103] (81.129.146.209) by re-prd-rgout-003.btmx-prd.synchronoss.net (5.8.716.04) (authenticated as jonturney@btinternet.com) id 61A69BAC05F90B20; Mon, 24 Jan 2022 15:02:44 +0000 Message-ID: <37ce4364-d009-4280-ebf2-739b5aa6a66d@dronecode.org.uk> Date: Mon, 24 Jan 2022 15:02:24 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: Cygwin/X with Win10 display scaling corrupting font display of typed characters - Issue identified Content-Language: en-GB To: Ken Whitesell , The Cygwin Mailing List References: <02b8ba82-0a40-e9ea-c4e6-fe201097d957@comcast.net> <4f4d8d34-3e30-82fe-4be2-2926da2c1c6a@dronecode.org.uk> From: Jon Turney In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-3571.0 required=5.0 tests=BAYES_00, FORGED_SPF_HELO, KAM_DMARC_STATUS, KAM_LAZY_DOMAIN_SECURITY, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_PASS, SPF_NONE, TXREP autolearn=no autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: cygwin@cygwin.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: General Cygwin discussions and problem reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 24 Jan 2022 15:02:56 -0000 On 20/01/2022 01:01, Ken Whitesell wrote: > On 1/19/2022 2:28 PM, Jon Turney wrote: >> On 19/01/2022 00:02, Ken Whitesell wrote: >>> On 1/17/2022 1:29 PM, Ken Whitesell wrote: >>>> >>>> Is there a known solution for this? (Or is it known that there is no >>>> solution?) >> >> Thanks for reporting this. >> >>>> Any guidance, pointers, suggestions of avenues for further research, >>>> or other information, will all be greatly appreciated. >>>> >>> After more research and experimentation, it appears to be related to >>> one of xorg-server, xorg-server-common, or xorg-server-xorg. >>> >>> Installing the older version 1.20.12-1 of these packages allows the >>> windows to be moved between monitors without any issues. Upgrading to >>> the current version 21.1.3-1 creates the problems. I'm able to >>> replicate this behavior on two different laptops with two different >>> external monitors. >> >> It seems likely that this is an unintended effect of changes in >> xorg-server 21.1.0-1, trying to fix problems in this area (See [1]) > > Thanks for the references. I've read all the messages in the thread - I > was particularly intrigued by this comment: > > wrt the font scaling issue, looking at the source, it seems that we > don't re-consider the display dpi after a WM_DISPLAYCHANGE message, but > keep on using the value determined at startup.  This is probably a bug. > > I'm curious enough to want to take a look at the code, but I've got no > belief that I'm going to be able to find an answer. (I'm *not* a C++ > programmer. I can read it and write a little of it, but that's about > it.) I was going to start by comparing the last known-working version to > the first known-non-working version, but given that it's a major release > change, that's not likely going to be a useful approach. (I'm way out of > my league here. It's probably going to take me a long time just to get > to the point where I can even begin to explore this.) The relevant change, which tries to fix the issue identified in that comment, and probably introduces this issue is: https://gitlab.freedesktop.org/jturney/xserver/-/commit/b19b6266d33f2b911dc1826ad5c03da135a39957 [...] >>> If I change the scaling from 125% to 100% on the laptop's display, >>> the problem appears until I restart Cygwin/X. Restarting Cygwin/X >>> shows it displaying properly, until I change the scaling again. >> >> I could only reproduce this problem with mis-rendering when changing >> the scaling on the secondary monitor. > > Wow, I did a really poor job of writing that. I'm sorry. > > For clarity, just in case you were unable to interpret what I meant by > what I wrote - > > At start: Laptop scaling set at 125%, second monitor at 100%. > > Mis-rendering occurs at start, on the second monitor only. > > If I change the scaling on the laptop, while the current instance of > XWin is running - the same mis-rendering now occurs on the laptop. > > Interestingly enough, if I change the laptop from 125% to 100%, the tops > are clipped as previously reported. But if I change the scaling from > 125% to 150%, then the bottoms are clipped. (It kinda makes sense from > what you've written.) > > If I then stop and restart XWin after having reset the scaling such that > both monitors have the same setting, then the problem doesn't appear. Thanks for the clarification. The laptop display is the primary monitor in all cases, correct?