From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Mario Valencia Newsgroups: gmane.emacs.bugs Subject: bug#14721: slow scrolling on windows 7 Date: Fri, 28 Jun 2013 01:28:53 -0500 Message-ID: References: <83sj05h97i.fsf@gnu.org> <83r4fohowh.fsf@gnu.org> <83fvw4hktv.fsf@gnu.org> <83a9mcgt5t.fsf@gnu.org> <83ip0yg4p9.fsf@gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=089e013a129a236fdc04e030feb1 X-Trace: ger.gmane.org 1372401014 30374 80.91.229.3 (28 Jun 2013 06:30:14 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 28 Jun 2013 06:30:14 +0000 (UTC) Cc: 14721@debbugs.gnu.org To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Fri Jun 28 08:30:14 2013 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1UsSCD-0003Mv-Qp for geb-bug-gnu-emacs@m.gmane.org; Fri, 28 Jun 2013 08:30:14 +0200 Original-Received: from localhost ([::1]:44679 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UsSCD-0000DN-CZ for geb-bug-gnu-emacs@m.gmane.org; Fri, 28 Jun 2013 02:30:13 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:45798) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UsSC8-0000AE-77 for bug-gnu-emacs@gnu.org; Fri, 28 Jun 2013 02:30:10 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UsSC4-0004U7-GM for bug-gnu-emacs@gnu.org; Fri, 28 Jun 2013 02:30:08 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:51866) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UsSC4-0004Sp-D4 for bug-gnu-emacs@gnu.org; Fri, 28 Jun 2013 02:30:04 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.80) (envelope-from ) id 1UsSC2-0007wN-EX for bug-gnu-emacs@gnu.org; Fri, 28 Jun 2013 02:30:03 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Mario Valencia Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Fri, 28 Jun 2013 06:30:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 14721 X-GNU-PR-Package: emacs,w32 X-GNU-PR-Keywords: Original-Received: via spool by 14721-submit@debbugs.gnu.org id=B14721.137240094430291 (code B ref 14721); Fri, 28 Jun 2013 06:30:02 +0000 Original-Received: (at 14721) by debbugs.gnu.org; 28 Jun 2013 06:29:04 +0000 Original-Received: from localhost ([127.0.0.1]:46181 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1UsSB5-0007sQ-JW for submit@debbugs.gnu.org; Fri, 28 Jun 2013 02:29:04 -0400 Original-Received: from mail-vc0-f182.google.com ([209.85.220.182]:65347) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1UsSB1-0007rY-7O for 14721@debbugs.gnu.org; Fri, 28 Jun 2013 02:29:00 -0400 Original-Received: by mail-vc0-f182.google.com with SMTP id id13so636987vcb.13 for <14721@debbugs.gnu.org>; Thu, 27 Jun 2013 23:28:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=GfH7wLKvrNwk5PCl50rXmzdzeK+Ey42NNwIPGs4ENWA=; b=ZXxtmzLwGmkTdE8+EXNOkfx0hqujDqeo+opWt7DgmJK9hPTimqg8OO2YYcFPbbVVFZ YtL5Wrq90FIpRk8t2JKvatCZ8xyTRPi98OK9cYIAjWVr85G6z+A0U/NRWtoSaiofK7Wh UQhtJ5RPdQeLYh7Sdp0rUrFkAk6nMnvkdWAaD+iuJ6BAkBBmJYm+VLkwZW3v4nEzv2/u uh7kkD1glGIFHkY2SdNkEg4AmhgoyLmLHQPnLsNGNS9oXIeOALETvoK21yfYAXgCWdio FofYZ+zW2P6ifccLptk+RAPLj35WtnieC6dDFkcAdD/eBOqGI6uu45Gn/Cy7XZUIXJjK 31zQ== X-Received: by 10.52.122.70 with SMTP id lq6mr2008542vdb.44.1372400933628; Thu, 27 Jun 2013 23:28:53 -0700 (PDT) Original-Received: by 10.58.75.14 with HTTP; Thu, 27 Jun 2013 23:28:53 -0700 (PDT) In-Reply-To: <83ip0yg4p9.fsf@gnu.org> X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 140.186.70.43 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-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:75671 Archived-At: --089e013a129a236fdc04e030feb1 Content-Type: text/plain; charset=ISO-8859-1 Well I guess that's it then, there's no way to fix it. :( 2013/6/28 Eli Zaretskii > [Please keep the bug address on the CC list.] > > > Date: Thu, 27 Jun 2013 17:55:15 -0500 > > From: Mario Valencia > > > > I don't know why scrolling has to be so slow. I certainly don't have that > > problem with any other text editor. > > Emacs have a lot of display-related features other editors don't, > which makes the simplest display-oriented operations very complex > under the hood. > > Just to give you an idea of the complexity: when text includes > variable-size fonts and images, how do you know where is the start of > the next or previous window-full, in terms of character positions? > E.g., if the next/previous line beyond the current window is a large > image, scrolling would mean to move the viewport by a single line. By > contrast, if you are in some kind of folding mode, which hides a lot > of text, the next/previous window start can be very far away. There's > no way Emacs can know this in advance, so it actually scans the text > before and after the window to decide where to start the next > window-full. > > > Moreover, it scrolls just fine with the scroll bar. > > Scroll bar scrolls by smaller amounts, so Emacs succeeds to optimize > redisplay and keep up. > > > And why is scrolling up with PgUp much slower than scrolling down? > > For boring technical reasons, scrolling up and down use very different > code paths in the display engine. > --089e013a129a236fdc04e030feb1 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Well I guess that's it then, there's no way to fix= it. :(


2013/6/28 Eli Zaretskii <eliz@gnu.org>
[Please keep the bug address on the CC list.= ]

> Date: Thu, 27 Jun 2013 17:55:15 -0500
> From: Mario Valencia <mari= ovalspi@gmail.com>
>
> I don't know why scrolling has to be so slow. I = certainly don't have that
> problem with any other text editor.

Emacs have a lot of display-related features other editors don't,=
which makes the simplest display-oriented operations very complex
under the hood.

Just to give you an idea of the complexity: when text includes
variable-size fonts and images, how do you know where is the start of
the next or previous window-full, in terms of character positions?
E.g., if the next/previous line beyond the current window is a large
image, scrolling would mean to move the viewport by a single line. =A0By contrast, if you are in some kind of folding mode, which hides a lot
of text, the next/previous window start can be very far away. =A0There'= s
no way Emacs can know this in advance, so it actually scans the text
before and after the window to decide where to start the next
window-full.

> Moreover, it scrolls just fine with the scroll bar.

Scroll bar scrolls by smaller amounts, so Emacs succeeds to optimize<= br> redisplay and keep up.

> And why is scrolling up with PgUp much slower than scrolling down?

For boring technical reasons, scrolling up and down use very differen= t
code paths in the display engine.

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