From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#38731: [PATCH] Calculate first glyph to be redrawn when exposing (bug#38731) Date: Sat, 28 Dec 2019 10:54:50 +0200 Message-ID: <83v9q0omn9.fsf@gnu.org> References: <20191227143500.GA75733@breton.holly.idiocy.org> <20191227162620.GA92799@breton.holly.idiocy.org> <83a77dpu28.fsf@gnu.org> <20191227190652.GA92850@breton.holly.idiocy.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="71770"; mail-complaints-to="usenet@blaine.gmane.org" Cc: netjune@outlook.com, 38731@debbugs.gnu.org To: Alan Third Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Sat Dec 28 09:55:11 2019 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1il7sM-000IWJ-0p for geb-bug-gnu-emacs@m.gmane.org; Sat, 28 Dec 2019 09:55:10 +0100 Original-Received: from localhost ([::1]:41962 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1il7sK-0001lh-RW for geb-bug-gnu-emacs@m.gmane.org; Sat, 28 Dec 2019 03:55:08 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:44187) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1il7sF-0001lO-I7 for bug-gnu-emacs@gnu.org; Sat, 28 Dec 2019 03:55:04 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1il7sE-0004Tt-9Y for bug-gnu-emacs@gnu.org; Sat, 28 Dec 2019 03:55:03 -0500 Original-Received: from debbugs.gnu.org ([209.51.188.43]:51975) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1il7sE-0004T4-5A for bug-gnu-emacs@gnu.org; Sat, 28 Dec 2019 03:55:02 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1il7sE-0006Wa-2g for bug-gnu-emacs@gnu.org; Sat, 28 Dec 2019 03:55:02 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sat, 28 Dec 2019 08:55:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 38731 X-GNU-PR-Package: emacs Original-Received: via spool by 38731-submit@debbugs.gnu.org id=B38731.157752329925068 (code B ref 38731); Sat, 28 Dec 2019 08:55:02 +0000 Original-Received: (at 38731) by debbugs.gnu.org; 28 Dec 2019 08:54:59 +0000 Original-Received: from localhost ([127.0.0.1]:57948 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1il7sB-0006WG-Bs for submit@debbugs.gnu.org; Sat, 28 Dec 2019 03:54:59 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:60723) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1il7s9-0006W4-UO for 38731@debbugs.gnu.org; Sat, 28 Dec 2019 03:54:58 -0500 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:59191) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1il7s4-0003vQ-2e; Sat, 28 Dec 2019 03:54:52 -0500 Original-Received: from [176.228.60.248] (port=3758 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1il7s3-0005i3-Bd; Sat, 28 Dec 2019 03:54:51 -0500 In-reply-to: <20191227190652.GA92850@breton.holly.idiocy.org> (message from Alan Third on Fri, 27 Dec 2019 19:06:52 +0000) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.51.188.43 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.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:173839 Archived-At: > Date: Fri, 27 Dec 2019 19:06:52 +0000 > From: Alan Third > Cc: netjune@outlook.com, 38731@debbugs.gnu.org > > The actual problem is that if there is a face that’s to extend to the > end of the line (for example with global-hl-line-mode) then > expose_area asks draw_glyphs to draw glyph 0 at x coordinate 0, even > though in this case there is horizontal scrolling in effect that means > glyph 0 should be at a negative x coordinate. > > In my case I could see that row->x in expose_area was set to -42 but > expose_area called draw_glyphs with an x parameter of 0. This offset > the glyphs on the screen by 42 pixels. I could see this both in > debugging printfs and by actually measuring the difference between the > cursor and the equivalent text as drawn on the screen. You are saying that, when the window is hscrolled, the glyphs in the glyph row start with the glyph for the very first character of the physical line in this case? IOW, if the line's text is "abcdef", then row->glyphs[TEXT_AREA] is the glyph for the character 'a', even though the line is hscrolled? This shouldn't happen, because display_line, the function which produces glyphs in glyph rows, starts producing the glyphs at the first one that is actually visible, thus taking the hscroll into account. See the code in display_line that follows this comment: /* Move over display elements that are not visible because we are hscrolled. This may stop at an x-position < first_visible_x if the first glyph is partially visible or if we hit a line end. */ if (it->current_x < it->first_visible_x + x_incr) So if in your case you get a glyph row with all the characters, including those which are scrolled out of the viewport, then something is wrong where the glyph row is prepared, not where it is displayed. Specifically, when the window is hscrolled, display_line is called again to produce the glyphs starting from the first visible glyph. Perhaps in this case the NS display machinery uses a stale glyph row, from before the hscrolling?