tutorial on faces ?

tutorial on faces ?

[Jean-Christophe Helary]

Is there a tutorial somewhere on how to use faces ?


Jean-Christophe Helary
-----------------------------------------------
http://mac4translators.blogspot.com @brandelune

RE: tutorial on faces ?

[Drew Adams]

> Is there a tutorial somewhere on how to use faces ?

What do you mean by "use faces"?  There are lots of
possible uses of faces, and lots of ways implement
such use cases to apply, search for, change,...
whatever faces.

It might help (you and others) if you elaborated a
bit, making your question more specific.  Unless
you're just asking for info about any tutorials
that involve using faces in some way.

Re: tutorial on faces ?

[Jean-Christophe Helary]

> On Feb 7, 2019, at 0:22, Drew Adams <drew.adams@oracle.com> wrote:
> 
>> Is there a tutorial somewhere on how to use faces ?
> 
> What do you mean by "use faces"?  There are lots of
> possible uses of faces, and lots of ways implement
> such use cases to apply, search for, change,...
> whatever faces.
> 
> It might help (you and others) if you elaborated a
> bit, making your question more specific.  Unless
> you're just asking for info about any tutorials
> that involve using faces in some way.

:) Thank you Drew.

Well, I'm tweaking poker.el at the moment and I'm looking for ways to apply style to some parts of the messages.

Honestly, the elisp manual gives me no idea how to do that...

Jean-Christophe Helary
-----------------------------------------------
http://mac4translators.blogspot.com @brandelune

RE: tutorial on faces ?

[Drew Adams]

> Well, I'm tweaking poker.el at the moment and I'm looking for ways to
> apply style to some parts of the messages.
> 
> Honestly, the elisp manual gives me no idea how to do that...

OK, good.  But what do you mean by "style"?
Do you mean that you want to apply a face to some
parts of some messages?

If so:

1. Do you want to apply the face to the buffer
   _positions_ of those msg parts, as an _overlay_
   property, or do you want to apply it to the
   _characters_ of those msg parts, as a _text_
   property?

2. Are those message parts recognizable/definable
   in a regular way, i.e., as something that you
   can define using one or more regexps?  And do
   you want the face highlighting to be
   automatically reapplied to those parts when
   the same text is visited anew (in the same
   mode), e.g. in a new Emacs session or after
   reverting the buffer?

   If the answer is yes then look at using
   `font-lock-mode' to define and highlight those
   parts.  If the answer is no then maybe look
   at using ad hoc highlighting, such as you get
   with library `highlight.el':

   https://www.emacswiki.org/emacs/HighlightLibrary

Knowing the answers to these, and perhaps other,
questions might help you direct your search for
tutorials (e.g. whether to look for tutorials
that involve font-lock highlighting).

The more you can specify about what you're
interested in, the more helpful people and search
can be.

Re: tutorial on faces ?

[Jean-Christophe Helary]

> On Feb 7, 2019, at 1:45, Drew Adams <drew.adams@oracle.com> wrote:
> 
>> Well, I'm tweaking poker.el at the moment and I'm looking for ways to
>> apply style to some parts of the messages.
>> 
>> Honestly, the elisp manual gives me no idea how to do that...
> 
> OK, good.  But what do you mean by "style"?
> Do you mean that you want to apply a face to some
> parts of some messages?

That's correct.

Coming from a HTML+CSS background, I thought that I could find a way to:

1) define some styles (for ex. "poker-action" as an already defined emacs standard style)

2) select the strings that need style (for ex "folds|calls|checks|raises")

3) apply the "poker-action" style to the defined selected strings

I was thus looking for a way to define styles, a way to select strings (or positions) and a way to apply the style to the selected strings.


> If so:
> 
> 1. Do you want to apply the face to the buffer
>   _positions_ of those msg parts, as an _overlay_
>   property, or do you want to apply it to the
>   _characters_ of those msg parts, as a _text_
>   property?

I don't know which is more appropriate to what I have.

> 2. Are those message parts recognizable/definable
>   in a regular way, i.e., as something that you
>   can define using one or more regexps?

Yes.

>  And do
>   you want the face highlighting to be
>   automatically reapplied to those parts when
>   the same text is visited anew (in the same
>   mode), e.g. in a new Emacs session or after
>   reverting the buffer?

I'm not sure I understand the question.

The way I've tweaked poker.el makes it (insert) strings that indicate player actions and results into a dedicated buffer. I'd like the buffer to always display the same style while the buffer exists.

There are some echo line (message) strings but I'm fine without having them styled.

>   If the answer is yes then look at using
>   `font-lock-mode' to define and highlight those
>   parts.  If the answer is no then maybe look
>   at using ad hoc highlighting, such as you get
>   with library `highlight.el':
> 
>   https://www.emacswiki.org/emacs/HighlightLibrary

So I guess the answer is Yes.

> Knowing the answers to these, and perhaps other,
> questions might help you direct your search for
> tutorials (e.g. whether to look for tutorials
> that involve font-lock highlighting).
> 
> The more you can specify about what you're
> interested in, the more helpful people and search
> can be.

Jean-Christophe Helary
-----------------------------------------------
http://mac4translators.blogspot.com @brandelune

RE: tutorial on faces ?

[Drew Adams]

> >  And do you want the face highlighting to be
> >   automatically reapplied to those parts when
> >   the same text is visited anew (in the same
> >   mode), e.g. in a new Emacs session or after
> >   reverting the buffer?
> 
> I'm not sure I understand the question.

Do you want the highlighting to be inherently
associated with particular patterns, so that
whenever a buffer with those patterns is visited
in a particular mode the patterns get highlighted.

As opposed to just wanting to highlight something
now, but not have the same highlighting done
automatically just because you revisit the same
text in the same mode later.
 
> The way I've tweaked poker.el makes it (insert) strings that indicate
> player actions and results into a dedicated buffer. I'd like the buffer
> to always display the same style while the buffer exists.
> 
> There are some echo line (message) strings but I'm fine without having
> them styled.

Messages in the echo area are a different story.
Instead of using font lock there, you just use
`propertize' to apply property `face' to the
parts of the message you want to highlight, then
call function `message'.

> >   If the answer is yes then look at using
> >   `font-lock-mode' to define and highlight those
> >   parts.
> 
> So I guess the answer is Yes.

It sounds like it (except for echo-area messaging).

I'm guessing you can find tutorials or videos or
blogs that introduce font-lock.  If not (or even
if so), consult the Elisp manual, starting with
node Font Lock Mode (`C-h i g (elisp)font lock mode').

https://www.gnu.org/software/emacs/manual/html_node/elisp/Font-Lock-Mode.html

Admittedly, that can be heavy going - font lock can
be complicated.  Start with an intro (e.g. blog), if
you find a good one.

Re: tutorial on faces ?

[Jean-Christophe Helary]

> On Feb 8, 2019, at 0:04, Drew Adams <drew.adams@oracle.com> wrote:
> 
>>> And do you want the face highlighting to be
>>>  automatically reapplied to those parts when
>>>  the same text is visited anew (in the same
>>>  mode), e.g. in a new Emacs session or after
>>>  reverting the buffer?
>> 
>> I'm not sure I understand the question.
> 
> Do you want the highlighting to be inherently
> associated with particular patterns, so that
> whenever a buffer with those patterns is visited
> in a particular mode the patterns get highlighted.

Yes. But I'm not sure I can call (my tweaked) poker.el a "mode". It is just a program that outputs strings based on inputs in a dedicated buffer.

> I'm guessing you can find tutorials or videos or
> blogs that introduce font-lock.  If not (or even
> if so), consult the Elisp manual, starting with
> node Font Lock Mode (`C-h i g (elisp)font lock mode').
> 
> https://www.gnu.org/software/emacs/manual/html_node/elisp/Font-Lock-Mode.html
> 
> Admittedly, that can be heavy going - font lock can
> be complicated.  Start with an intro (e.g. blog), if
> you find a good one.

Thank you.

Jean-Christophe Helary
-----------------------------------------------
http://mac4translators.blogspot.com @brandelune

RE: tutorial on faces ?

[Drew Adams]

> >>> And do you want the face highlighting to be
> >>>  automatically reapplied to those parts when
> >>>  the same text is visited anew (in the same
> >>>  mode), e.g. in a new Emacs session or after
> >>>  reverting the buffer?
> >>
> >> I'm not sure I understand the question.
> >
> > Do you want the highlighting to be inherently
> > associated with particular patterns, so that
> > whenever a buffer with those patterns is visited
> > in a particular mode the patterns get highlighted.
> 
> Yes. But I'm not sure I can call (my tweaked) poker.el a "mode". It is
> just a program that outputs strings based on inputs in a dedicated buffer.

The buffer is in a (major) mode.  You typically
define font-lock patterns for a given mode.
You can define your own major mode using
`define-derived-mode'.

I probably should have mentioned this: To highlight
parts of a string is one thing - use `propertize'
with property `face', for example.

To highlight parts of a buffer is something else.
You typically use font lock for this.  Font lock
periodically updates the highlighting, even as
you change buffer contents.  It applies a set of
highlighting rules (regexp patterns, for example),
in sequence.

Re: tutorial on faces ?

[Jean-Christophe Helary]

> On Feb 8, 2019, at 0:44, Drew Adams <drew.adams@oracle.com> wrote:

> I probably should have mentioned this: To highlight
> parts of a string is one thing - use `propertize'
> with property `face', for example.
> 
> To highlight parts of a buffer is something else.

How is that something else ?

> You typically use font lock for this.  Font lock
> periodically updates the highlighting, even as
> you change buffer contents.  It applies a set of
> highlighting rules (regexp patterns, for example),
> in sequence.

Isn't it something you'd always want ?

Jean-Christophe Helary
-----------------------------------------------
http://mac4translators.blogspot.com @brandelune

RE: tutorial on faces ?

[Drew Adams]

> > I probably should have mentioned this: To highlight
> > parts of a string is one thing - use `propertize'
> > with property `face', for example.
> >
> > To highlight parts of a buffer is something else.
> 
> How is that something else ?

See my previous mails.  Read about font lock.  Look
at some existing code that uses it.

Buffers are not strings.  They don't behave the same
and they're not used the same.  Buffers have a (major)
mode.  Buffers are displayed and redisplayed.

A string is a string.  A message displays a string,
typically ephemerally.  The echo area and minibuffer
are not used like other buffers; in particular, you
typically do not try to use font lock there.

> > You typically use font lock for this.  Font lock
> > periodically updates the highlighting, even as
> > you change buffer contents.  It applies a set of
> > highlighting rules (regexp patterns, for example),
> > in sequence.
> 
> Isn't it something you'd always want ?

See above.  Read more about font lock, and maybe
read more about buffers and strings.

And look at existing code that (1) uses font lock
and (2) uses `message' with propertized strings.