Re: Introducing face in comments for various modes

[Heime]

------- Original Message -------
On Monday, December 12th, 2022 at 9:58 AM, Thibaut Verron 
<thibaut.verron@gmail.com> wrote:


> On 12/12/2022 10:21, Heime wrote:
> 
> > ------- Original Message -------
> > On Monday, December 12th, 2022 at 8:49 AM, Thibaut Verron
> > thibaut.verron@gmail.com wrote:
> > 
> > > Le lun. 12 déc. 2022 à 04:01, Heime heimeborgia@protonmail.com a
> > > écrit :
> > > 
> > > ------- Original Message -------
> > > On Monday, December 12th, 2022 at 2:24 AM, Heime
> > > heimeborgia@protonmail.com wrote:
> > > 
> > > > ------- Original Message -------
> > > > On Sunday, December 11th, 2022 at 5:40 PM, Stefan Monnier via
> > > Users list for the GNU Emacs text editor help-gnu-emacs@gnu.org
> > > wrote:
> > > >
> > > > > BTW, there is a related convention in ELisp code where
> > > comments that
> > > > > start in column 0 and which are introduced with 3 or more
> > > semi-colons
> > > > > are considered sectioning headers (where ";;;" means a top-level
> > > > > header, ";;;;" a subheader, ";;;;;" a subsubheader, ...).
> > > > >
> > > > > I'd be happy if Emacs were changed to highlighting those.
> > > > >
> > > > > Stefan
> > > 
> > > If you are colourising "Sectioning Headers", ensure that vibrant
> > > and good contrast:
> > > 
> > > 1) betweenthe text and the background;
> > > 
> > > 2) and between a header, subheader, subsubheader, ...
> > > 
> > > Use some colour metric (e.g. using the Web Content Accessibility
> > > Guidelines [WCAG]).
> > > 
> > > Because I consistently see that developers almost never care (or
> > > have the skills)
> > > to properly set up colours. Have suggested changing the colour
> > > scheme as described,
> > > for "Org Headings" because they are indistinguishable against a
> > > dark background and
> > > between a heading and its subheading. Applying such metrics have
> > > been turned down,
> > > with the excuse that if I want them right, I have to work on
> > > emacs customisations
> > > myself, as the crappy colours are there to stay.
> > > 
> > > > The colors of the standard themes are chosen with its (light)
> > > > background in mind. If you change that background, it is not
> > > > surprising that things fall apart.
> > 
> > Choosing colours with a light background in mind is the wrong approach
> > because colours produce far greater visual
> > impact.
> 
> 
> There is no right or wrong approach, but individual preferences.

Standard metrics exist.  The Gnu Project like many others, does not
want to use them.
 
> If you want a dark background, just use a dark background theme. For
> instance, emacs has a built-in implementation of the tango dark color
> palette. If contrast if your primary concern, you should look at the
> modus themes (modus-vivendi for the dark background), which is also part
> of emacs now.
> 
> M-x customize-themes and make your choice.

If you use "modus-vivendi" for org-mode, the colours are all almost white,
a big problem particularly when you fold the org headings.
 
> > Rather, there there should be carefully chosen colour settings for
> > both light and dark backgrounds.
> 
> 
> That's how you end up with settings which are at best acceptable, but
> not perfect, for both light and dark backgrounds. The range of colors
> which are suitable for both light and dark backgrounds is just too narrow.
> 
> The proper way is the current way: carefully curated themes implementing
> all colors in a consistent ways.
 
What metrics are being used.  The blind belief that the proper way is the 
current way, is the origin of the problem. 
 
> > > > It is not a new problem, but it doesn't mean that you have to
> 
> customize all the individual faces yourself. Instead, you should look
> for a theme implementing
> 
> > > > the colors you like, and install it. The responsibility for having
> > > > consistent colors across all emacs fonts is on the theme designer.
> > > > You can still tweak some
> > > > faces from there if you choose to of course.
> > > 
> > > At any rate, Stefan's suggestion would not require making new design
> > > choices, as there are already faces designed for fontifying headers:
> > > outline-1, outline-2, etc.
> > 
> > Making a new design choice is a necessity if you want to move forward.
> 
> 
> No. The question is whether to fontify those headers, how to identify
> them, etc.
> 
> That's completely separate from the question of changing the face
> currently used for headers in other places.
> 
> > > Those faces are used by outline-mode, but not by outline-minor-mode
> > > (which emacs-lisp-mode uses to implement the ;;; comment headers) at
> > > the moment.
> > 
> > Which proves my point that changes are necessary. What needs to be
> > done is for colour contrast metrics
> > to be taken seriously by all packages, rather than relying on some
> > theme to fix the crappy default choices.
> 
> 
> Sorry to be blunt, but you couldn't be more wrong. For a start,
> outline-mode and outline-minor-mode are the same package. :)
> 
> But more to the point, with the current system, packages choose existing
> faces to implement coloring based on what they should color (e.g. is
> it a comment, is it a header, is it a keyword, is it something
> important). And the theme designers choose colors (and other features)
> for those faces.
> 
> As a result, colors are the same across all of Emacs (for example
> comments look the same in elisp and python), and -- if the theme maker
> is competent -- the colors will implement good contrast and be readable
> everywhere.

One can at least use good metrics for light (white) and dark (dark) background.
We have not even arrived at that yet.  I am not arguing against comments looking
the same, but that there should specific settings for the canonical white and
black background as minimum.
 
> If instead we were to let each package decide on its colors, Emacs would
> look like a Christmas tree with different colors all over the place. And
> most of them would be really crappy because the package developer was
> never trained in graphic design, or because they didn't plan for all
> possible background colors (it's not as simple as light and dark, some
> people use blue, or green backgrounds), or because they didn't predict
> that their choice of color would conflict with the choice made by a
> minor mode in another package, or...

Am only discussing for white background and black background, which are the
canonical settings for printing.  With colour contrast you are limited by
the metric values which limits to about eight colours.  

It is not Christmas Tree as you say.  Focusing on any possible colour 
combination
(blue, or green backgrounds) is beyond the scope of my discussion.

Quite reasonable and achievable if there is the will.
 
> You shouldn't think of themes as "fixing the default choices"
> (especially considering that you are the one "breaking" them by
> insisting to use them with a background they weren't designed for).
> Their purpose is to implement different choices in a consistent way.

Good design in much more important that consistency.
 
> > > >
> > > > > Heime [2022-12-11 15:35:41] wrote:
> > > > >
> > > > > > The following uses `hi-lock` to change the foreground of
> > > comments matching
> > > > > > a regexp. This is implemented for emacs-lisp files where
> > > comments start
> > > > > > with ";;".
> > > > > >
> > > > > > I would like to extend this for other programming languages
> > > besides emacs-lisp
> > > > > > files, using the relevant comment character automatically
> > > for that language.
> > > > > >
> > > > > > (defface elfa-face
> > > > > > '((t :foreground "magenta"))
> > > > > > "Face for comment headings.")
> > > > > >
> > > > > > (defun elfa-regexp (&optional actm)
> > > > > > "Identify comment category ';; [Category]'."
> > > > > > (highlight-regexp
> > > > > > "^;;\s+\\[.+\\].*$" 'elfa-face))
> > > > > >
> > > > > > (defun elfa-category ()
> > > > > > "TODO."
> > > > > > (interactive)
> > > > > > (add-to-list 'auto-mode-alist '("\\.el\\'" . hi-lock-mode))
> > > > > > (add-hook 'emacs-lisp-mode-hook 'hi-lock-mode t)
> > > > > > (add-hook 'hi-lock-mode-hook 'elfa-regexp))