Re: Mouse highlighting and fonts

[Stephen Berman]

On Fri, 23 May 2008 15:53:54 -0400 Chong Yidong <address@hidden> wrote:

> Chong Yidong <address@hidden> writes:
>
>> With the current CVS code, the mouse highlight preserves the size of the
>> underlying face, which avoids the meta-stability problem I mentioned a
>> few weeks ago.  However, mouse highlighting of the glyph background
>> still doesn't work right when the underlying font size varies across the
>> highlighted region.
>
> BTW, another mouse-highlighting bug I reported earlier is still present.
> Under certain circumstances, the area to the left and/or right of the
> physical cursor doesn't acquire the proper mouse-face.

This also sound like the bug I reported in
<http://permalink.gmane.org/gmane.emacs.devel/88763>.

> This appears to be a long-standing bug, but one that didn't show up
> until the new font code.  That's because it arises as follows: when the
> cursor glyph has a nonzero lbearing or rbearing (i.e., it overlaps with
> its neighbors), the neighboring glyphs are redrawn, and this can
> overwrite the mouse-face highlight.  See xdisp.c:19934.  This didn't
> show up because previously, overlapping glyphs were generally not
> encountered.
>
> I'll try to fix this once I get the time, unless someone else fixes it
> first.

I wish I knew how to fix it; in lieu of that, I look forward to testing
your patch!

Steve Berman