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Re: "Bold" effect when anti-aliased glyphs are overwritten
From: |
Stephen Berman |
Subject: |
Re: "Bold" effect when anti-aliased glyphs are overwritten |
Date: |
Wed, 28 May 2008 10:49:18 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.0.60 (gnu/linux) |
On Tue, 27 May 2008 17:09:29 -0400 Chong Yidong <address@hidden> wrote:
> Chong Yidong <address@hidden> 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.
It fixes the cases I have encountered. Thanks!
Steve Berman