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#44284: 27.1; with some Unicode font, scrolling upward with the mouse wheel actually scrolls downward when the cursor needs repositioning Date: Fri, 30 Oct 2020 22:58:25 +0200 Message-ID: <834kmba0su.fsf@gnu.org> References: <87zh46e296.fsf@cventin.lip.ens-lyon.fr> <83a6w6cmwe.fsf@gnu.org> <20201030105228.GB27593@zira.vinc17.org> <838sboar11.fsf@gnu.org> <20201030133336.GC27593@zira.vinc17.org> <83pn4zal89.fsf@gnu.org> <20201030163125.GD27593@zira.vinc17.org> <20201030203453.GF27593@zira.vinc17.org> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="19120"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 44284@debbugs.gnu.org To: Vincent Lefevre Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Fri Oct 30 21:59:08 2020 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 1kYbUK-0004s2-GE for geb-bug-gnu-emacs@m.gmane-mx.org; Fri, 30 Oct 2020 21:59:08 +0100 Original-Received: from localhost ([::1]:49114 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kYbUJ-0003kF-IW for geb-bug-gnu-emacs@m.gmane-mx.org; Fri, 30 Oct 2020 16:59:07 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:59390) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kYbUD-0003jt-Vh for bug-gnu-emacs@gnu.org; Fri, 30 Oct 2020 16:59:01 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:48373) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kYbUD-0003wV-Mx for bug-gnu-emacs@gnu.org; Fri, 30 Oct 2020 16:59:01 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1kYbUD-0001F6-Kw for bug-gnu-emacs@gnu.org; Fri, 30 Oct 2020 16:59:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Fri, 30 Oct 2020 20:59:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 44284 X-GNU-PR-Package: emacs Original-Received: via spool by 44284-submit@debbugs.gnu.org id=B44284.16040915314758 (code B ref 44284); Fri, 30 Oct 2020 20:59:01 +0000 Original-Received: (at 44284) by debbugs.gnu.org; 30 Oct 2020 20:58:51 +0000 Original-Received: from localhost ([127.0.0.1]:59919 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1kYbU2-0001Ef-Py for submit@debbugs.gnu.org; Fri, 30 Oct 2020 16:58:51 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:59252) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1kYbU1-0001EQ-7Q for 44284@debbugs.gnu.org; Fri, 30 Oct 2020 16:58:49 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:53734) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kYbTv-0003uV-Sb; Fri, 30 Oct 2020 16:58:43 -0400 Original-Received: from [176.228.60.248] (port=1535 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1kYbTu-0006Ss-43; Fri, 30 Oct 2020 16:58:42 -0400 In-Reply-To: <20201030203453.GF27593@zira.vinc17.org> (message from Vincent Lefevre on Fri, 30 Oct 2020 21:34:53 +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" Xref: news.gmane.io gmane.emacs.bugs:192200 Archived-At: > Date: Fri, 30 Oct 2020 21:34:53 +0100 > From: Vincent Lefevre > Cc: 44284@debbugs.gnu.org > > I've found the cause of this issue: with the culprit font, it is > not always possible to put the text cursor on the last line in > the window, either with a mouse click or with the down arrow: > Emacs scrolls the text so that the cursor is at the center of > the window. Why/when this occurs remains to be determined (is > there some rounding involved?). Emacs always requires that the line where point is should be fully visible. This is standard Emacs behavior, nothing new and nothing specific to any special font. > When the bug does not occur with the mouse wheel, the cursor is > put on the last line. But with the culprit font, I suppose that > the above issue causes another scroll in the opposite direction, > hence the observed behavior. I suspected that much, but I cannot reproduce this. When I arrange for the font to be of size that causes the last line of the window to be only partially visible, scrolling with the mouse always leaves point on the line above the last, which is fully visible. I couldn't cause the situation you describe, no matter what I tried. So there's some other factor at work here that somehow forces this aberrant behavior, and a reproduction recipe is needed to identify the code which causes it.