GNU bug report logs - #50660
28.0.50; Text artifacting when the cursor moves over text under mouse face that originally displayed a box

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Message #149 received at 50660 <at> debbugs.gnu.org (full text, mbox):

From: Po Lu <luangruo <at> yahoo.com>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: larsi <at> gnus.org, 50660 <at> debbugs.gnu.org
Subject: Re: bug#50660: 28.0.50; Text artifacting when the cursor moves over
 text under mouse face that originally displayed a box
Date: Sat, 02 Oct 2021 20:52:58 +0800

[Message part 1 (text/plain, inline)]

Eli Zaretskii <eliz <at> gnu.org> writes:

Thanks for the comments, I'm attaching a rectified patch.

I think the rest of what you've brought up has been resolved by the new
patch, but I would like to clarify something here:

> There's no reason to use -= and += here.  The callers never initialize
> the argument to anything but zero, nor should they.  This function
> _calculates_ the offset, it doesn't _correct_ it.  So a simple
> assignment should do better, because using the above begs the
> question: what could the initial value be?  The callers should add or
> subtract the corrections as they see fit.

I changed the function to use an internal accumulator variable
initialized to 0.  The -= and += is still necessary, as we are inside a
loop which can potentially go through many glyphs that are relevant.

Thanks.

[fix-cursor-position.patch (text/x-patch, attachment)]

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