From: Michael Heerdegen <michael_heerdegen@web.de>
To: Eli Zaretskii <eliz@gnu.org>
Cc: 15900@debbugs.gnu.org
Subject: bug#15900: 24.3.50; foreground-color-at-point returns wrong results
Date: Fri, 15 Nov 2013 23:18:11 +0100 [thread overview]
Message-ID: <878uwpgvh8.fsf@web.de> (raw)
In-Reply-To: <83li0qhxyl.fsf@gnu.org> (Eli Zaretskii's message of "Fri, 15 Nov 2013 10:26:58 +0200")
Hello,
CCing Drew cause the Change Log mentions him with regard to
`foreground-color-at-point'.
Eli Zaretskii <eliz@gnu.org> writes:
> As you later discovered, even (face-at-point nil t) doesn't do the
> job.
>
> Which doesn't surprise me a bit: this kind of things cannot be done
> reliably from Lisp, even at a price of the kind of obfuscated code
> that face-at-point and foreground-color-at-point use. It is much
> simpler to write a C primitive that simulates the display, then
> returns the resulting face at a given character position, a simple and
> straightforward task on the C level, something the display engine does
> all the time.
That sounds good. Can we just do that?
> > P.S. Some background: I'm working on an addition to stripe-buffer.el
> > that changes the foreground color continuously, instead of changing the
> > background. This is for better readability.
> >
> > I want to keep the foreground colors already present, so that e.g. links
> > in w3m are still recognizable. Paragraphs in italic can be colored
> > OTOH.
> >
> > So, what I need is a reliable `foreground-color-at-point'. Tips and
> > alternatives welcome.
>
> Why can't you detect that a portion of text is covered by specific
> properties (e.g., one of a list of known properties), and leave those
> portions alone?
What do you mean with "properties" - text and overlay properties? If
faces are among them, I still must figure out if one of these faces
changes the foreground. If not, i.e., if a face e.g. just underlines, I
do want to color the text nevertheless. Probably I didn't understand
what you meant. This expression works ok for me:
--8<---------------cut here---------------start------------->8---
(cl-some
(lambda (face) (not (memq (face-foreground face nil t)
`(nil
,(face-attribute 'default :foreground)
"unspecified-fg" "unspecified-bg"))))
(cl-mapcan (lambda (face-or-list) (if (facep face-or-list)
(list face-or-list)
face-or-list))
(list
(get-text-property (point) 'face)
(get-text-property (point) 'font-lock-face))))
--8<---------------cut here---------------end--------------->8---
Overlays are not covered by this - which is not even necessary, because
overlays have priorities that can be controlled.
Thanks,
Michael.
next prev parent reply other threads:[~2013-11-15 22:18 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-15 2:04 bug#15900: 24.3.50; foreground-color-at-point returns wrong results Michael Heerdegen
2013-11-15 2:47 ` Michael Heerdegen
2013-11-15 8:26 ` Eli Zaretskii
2013-11-15 22:18 ` Michael Heerdegen [this message]
2013-11-16 0:26 ` Drew Adams
2013-11-16 8:57 ` Eli Zaretskii
2013-11-16 8:44 ` Eli Zaretskii
2013-11-17 2:33 ` Michael Heerdegen
2013-11-17 3:52 ` Eli Zaretskii
2013-11-17 5:35 ` Michael Heerdegen
2013-11-17 17:21 ` Eli Zaretskii
2022-04-22 13:30 ` Lars Ingebrigtsen
[not found] <<87siuyxvw7.fsf@web.de>
[not found] ` <<83li0qhxyl.fsf@gnu.org>
[not found] ` <<878uwpgvh8.fsf@web.de>
[not found] ` <<b0006d1c-b470-4297-a6d7-97d7ed118c28@default>
[not found] ` <<83vbzshggy.fsf@gnu.org>
2013-11-16 16:20 ` Drew Adams
2013-11-16 16:40 ` Eli Zaretskii
[not found] ` <<83y54ohh1n.fsf@gnu.org>
[not found] ` <<87siuv21v8.fsf@web.de>
[not found] ` <<83eh6fhegu.fsf@gnu.org>
[not found] ` <<87eh6flhfc.fsf@web.de>
[not found] ` <<83d2lzgd04.fsf@gnu.org>
2013-11-17 17:29 ` Drew Adams
2013-11-17 17:47 ` Eli Zaretskii
2013-11-17 22:38 ` Michael Heerdegen
2013-11-18 3:42 ` Eli Zaretskii
2013-11-18 7:50 ` Michael Heerdegen
[not found] <<6bc49739-fae0-4688-a3cc-8bbbc2fe1c04@default>
[not found] ` <<83li0ogv14.fsf@gnu.org>
2013-11-16 17:47 ` Drew Adams
2013-11-16 18:18 ` Eli Zaretskii
[not found] <<c18e0f8c-e172-497d-b572-69162d77132b@default>
[not found] ` <<83iovsgqhn.fsf@gnu.org>
2013-11-16 22:53 ` Drew Adams
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