From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Chong Yidong Newsgroups: gmane.emacs.devel Subject: Re: "Bold" effect when anti-aliased glyphs are overwritten Date: Tue, 27 May 2008 17:09:29 -0400 Message-ID: <87mymb4fp2.fsf@stupidchicken.com> References: <87ve0zmy8p.fsf@stupidchicken.com> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1211922900 13268 80.91.229.12 (27 May 2008 21:15:00 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 27 May 2008 21:15:00 +0000 (UTC) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue May 27 23:15:41 2008 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1K16W7-0003zi-NK for ged-emacs-devel@m.gmane.org; Tue, 27 May 2008 23:15:36 +0200 Original-Received: from localhost ([127.0.0.1]:59363 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1K16VK-0008JG-Qt for ged-emacs-devel@m.gmane.org; Tue, 27 May 2008 17:14:46 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1K16UU-0008A9-I9 for emacs-devel@gnu.org; Tue, 27 May 2008 17:13:54 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1K16UP-00088d-IX for emacs-devel@gnu.org; Tue, 27 May 2008 17:13:53 -0400 Original-Received: from [199.232.76.173] (port=38462 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1K16UP-00088Y-Eo for emacs-devel@gnu.org; Tue, 27 May 2008 17:13:49 -0400 Original-Received: from cyd.mit.edu ([18.115.2.24]:37101) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1K16UO-0003Hi-UB for emacs-devel@gnu.org; Tue, 27 May 2008 17:13:49 -0400 Original-Received: by cyd.mit.edu (Postfix, from userid 1000) id 89FE74E2E6; Tue, 27 May 2008 17:09:29 -0400 (EDT) In-Reply-To: <87ve0zmy8p.fsf@stupidchicken.com> (Chong Yidong's message of "Tue, 27 May 2008 13:51:34 -0400") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.60 (gnu/linux) X-detected-kernel: by monty-python.gnu.org: Linux 2.6 (newer, 2) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:97832 Archived-At: Chong Yidong writes: > I've been noticing that glyphs near the cursor occasionally become > "bold" for no reason. > > The reason this happens is that when the redisplay engine calls > draw_glyphs to draw certain glyphs, such as the cursor glyph, > neighboring glyphs are redrawn if there is a left or right overhang > (xdisp.c:19929). > > With anti-aliasing, it doesn't work well. Apparently, during the > anti-aliasing calculation, the entire existing glyph---including the > glyph foreground---is treated as the "background". Thus, the > anti-aliased parts of the foreground character becomes more and more > prominent, and eventually saturates completely. I've checked in a fix into CVS. Please let me know if it causes any problems.