Ef (εὖ) themes for GNU Emacs

Colorful and legible themes for GNU Emacs.

IMAGES HERE: https://protesilaos.com/emacs/ef-themes-pictures

This manual, written by Protesilaos Stavrou, describes the Emacs package called ef-themes, and provides every other piece of information pertinent to it.

The documentation furnished herein corresponds to stable version 0.5.0, released on 2022-09-11. Any reference to a newer feature which does not yet form part of the latest tagged commit, is explicitly marked as such.

Current development target is 0.6.0-dev.

If you are viewing the README.org version of this file, please note that the GNU ELPA machinery automatically generates an Info manual out of it.

1. COPYING

Copyright (C) 2022 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover Texts being “A GNU Manual,” and with the Back-Cover Texts as in (a) below. A copy of the license is included in the section entitled “GNU Free Documentation License.”

(a) The FSF’s Back-Cover Text is: “You have the freedom to copy and modify this GNU manual.”

2. Installation

2.1. GNU ELPA package

The package is available as ef-themes. Simply do:

M-x package-refresh-contents
M-x package-install

And search for it.

GNU ELPA provides the latest stable release. Those who prefer to follow the development process in order to report bugs or suggest changes, can use the version of the package from the GNU-devel ELPA archive. Read: https://protesilaos.com/codelog/2022-05-13-emacs-elpa-devel/.

2.2. Manual installation

Assuming your Emacs files are found in ~/.emacs.d/, execute the following commands in a shell prompt:

cd ~/.emacs.d

# Create a directory for manually-installed packages
mkdir manual-packages

# Go to the new directory
cd manual-packages

# Clone this repo, naming it "ef-themes"
git clone https://git.sr.ht/~protesilaos/ef-themes ef-themes

Finally, in your init.el (or equivalent) evaluate this:

;; Make Elisp files in that directory available to the user.
(add-to-list 'load-path "~/.emacs.d/manual-packages/ef-themes")

Everything is in place to set up the package.

3. Sample configuration

(require 'ef-themes)

;; If you like two specific themes and want to switch between them, you
;; can specify them in `ef-themes-to-toggle' and then invoke the command
;; `ef-themes-toggle'.  All the themes are included in the variable
;; `ef-themes-collection'.
(setq ef-themes-to-toggle '(ef-summer ef-winter))

;; Make customisations that affect Emacs faces BEFORE loading a theme
;; (any change needs a theme re-load to take effect).

(setq ef-themes-headings ; read the manual's entry or the doc string
      '((0 . (variable-pitch light 1.9))
        (1 . (variable-pitch light 1.8))
        (2 . (variable-pitch regular 1.7))
        (3 . (variable-pitch regular 1.6))
        (4 . (variable-pitch regular 1.5))
        (5 . (variable-pitch 1.4)) ; absence of weight means `bold'
        (6 . (variable-pitch 1.3))
        (7 . (variable-pitch 1.2))
        (t . (variable-pitch 1.1))))

;; They are nil by default...
(setq ef-themes-mixed-fonts t
      ef-themes-variable-pitch-ui t)

;; Disable all other themes to avoid awkward blending:
(mapc #'disable-theme custom-enabled-themes)

;; Load the theme of choice:
(load-theme 'ef-summer :no-confirm)

;; OR use this to load the theme which also calls `ef-themes-post-load-hook':
(ef-themes-select 'ef-summer)

;; The themes we provide:
;;
;; Light: `ef-day', `ef-duo-light', `ef-light', `ef-spring', `ef-summer', `ef-trio-light'.
;; Dark:  `ef-autumn', `ef-duo-dark', `ef-dark', `ef-night', `ef-trio-dark', `ef-winter'.
;;
;; Also those which are optimized for deuteranopia (red-green color
;; deficiency): `ef-deuteranopia-dark', `ef-deuteranopia-light'.

;; We also provide these commands, but do not assign them to any key:
;;
;; - `ef-themes-toggle'
;; - `ef-themes-select'
;; - `ef-themes-load-random'
;; - `ef-themes-preview-colors'
;; - `ef-themes-preview-colors-current'

4. Themes for red-green color deficiency

Most items in the ef-themes collection are designed to use colors from many sides of the spectrum. Those items generally are inappropriate for people with red-green color deficiency or deuteranopia. We do, nonetheless, provide a light and a dark theme that are optimized for such users. The named of the themes are: ef-deuteranopia-dark and ef-deuteranopia-light (Loading a theme).

5. Customization options

The ef-themes provide a limited set of user options which tweak secondary aspects of the theme. No option affects coloration or the overall character of each theme (Principles).

All customizations need to be evaluated before loading a theme. Any change thus requires a theme re-load (Loading a theme).

5.1. Toggle between two Ef themes

The user option ef-themes-to-toggle expects two symbols that name items in the Ef themes collection. The variable ef-themes-collection includes a list with all relevant symbols. The user can then switch between the two specified themes by invoking the ef-themes-toggle command.

If ef-themes-to-toggle does not specify two Ef themes, inform the user about it while prompting with completion for a theme among our collection (this is practically the same as the ef-themes-select command).

This command is in addition to the other ways of loading a theme, either with minibuffer completion or at random (Commands to load an Ef theme).

5.2. Enable mixed fonts

The user option ef-themes-mixed-fonts controls whether strictly spacing-sensitive constructs inherit from fixed-pitch (a monospaced font family).

By default (a nil value for this user option) no face inherits from fixed-pitch: they all use the default font family, regardless of whether it is monospaced or not.

When ef-themes-mixed-fonts is set to a non-nil value, faces such as Org tables, inline code, code blocks, and the like, are rendered in a monospaced font at all times. The user can thus set their default font family to a proportionately spaced font without worrying about breaking the alignment of relevant elements, or if they simply prefer the aesthetics of mixed mono and proportionately spaced font families.

A temporary switch to a proportionately spaced font (known in Emacs as variable-pitch) can be enabled in the current buffer with the activation of the built-in variable-pitch-mode.

To get consistent typography, the user may need to edit the font family of the fixed-pitch face. The fontaine package on GNU ELPA (by Protesilaos) can be helpful in that regard.

5.3. UI typeface

The user option ef-themes-variable-pitch-ui controls whether the elements of the User Interface (UI) use a proportionately spaced font. By default (a nil value), all UI elements use the default font family. When this user option is set to a non-nil value, all UI elements will inherit the face variable-pitch instead thus rendering them in a proportionately spaced font.

In this context, the UI elements are:

  • header-line
  • mode-line (active and inactive)
  • tab-bar-mode
  • tab-line-mode

To get consistent typography, the user may need to edit the font family of the variable-pitch face. The fontaine package on GNU ELPA (by Protesilaos) can be helpful in that regard.

5.4. Option for headings

The user option ef-themes-headings provides support for individual heading styles for levels 0 through 8.

This is an alist that accepts a (key . list-of-values) combination. The key is either a number, representing the heading’s level (0 through 8) or t, which pertains to the fallback style.

Level 0 is a special heading: it is used for what counts as a document title or equivalent, such as the #+title construct we find in Org files. Levels 1-8 are regular headings.

The list of values covers symbols that refer to properties, as described below. Here is a complete sample, followed by a presentation of all available properties:

(setq ef-themes-headings
      '((1 . (light variable-pitch 1.5))
        (2 . (regular 1.3))
        (3 . (1.1))
        (t . (variable-pitch))))

By default (a nil value for this variable), all headings have a bold typographic weight, a font family that is the same as the default face (typically monospaced), and a height that is equal to the default face’s height.

  • A variable-pitch property changes the font family of the heading to that of the variable-pitch face (normally a proportionately spaced typeface). Also check the fontaine package (by Protesilaos) for tweaking fonts via faces.
  • The symbol of a weight attribute adjusts the font of the heading accordingly, such as light, semibold, etc. Valid symbols are defined in the variable ef-themes-weights. The absence of a weight means that bold will be used by virtue of inheriting the bold face.
  • A number, expressed as a floating point (e.g. 1.5), adjusts the height of the heading to that many times the base font size. The default height is the same as 1.0, though it need not be explicitly stated. Instead of a floating point, an acceptable value can be in the form of a cons cell like (height . FLOAT) or (height FLOAT), where FLOAT is the given number.

Combinations of any of those properties are expressed as a list, like in these examples:

(semibold)
(variable-pitch semibold)
(variable-pitch semibold 1.3)
(variable-pitch semibold (height 1.3))   ; same as above
(variable-pitch semibold (height . 1.3)) ; same as above

The order in which the properties are set is not significant.

In user configuration files the form may look like this:

(setq ef-themes-headings
      '((1 . (light variable-pitch 1.5))
        (2 . (regular 1.3))
        (3 . (1.1))
        (t . (variable-pitch))))

When defining the styles per heading level, it is possible to pass a non-nil value (t) instead of a list of properties. This will retain the original aesthetic for that level. For example:

(setq ef-themes-headings
      '((1 . t)           ; keep the default style
        (2 . (variable-pitch 1.2))
        (t . (variable-pitch)))) ; style for all other headings

(setq ef-themes-headings
      '((1 . (variable-pitch 1.6))
        (2 . (1.3))
        (t . t))) ; default style for all other levels

6. Loading a theme

Emacs can load and maintain enabled multiple themes at once. This typically leads to awkward styling and weird combinations. The theme looks broken and the designer’s intent is misunderstood. Before loading one of the ef-themes, the user is encouraged to disable all others:

(mapc #'disable-theme custom-enabled-themes)

Then load the theme of choice. For example:

(load-theme 'ef-summer :no-confirm)

The :no-confirm is optional. It simply skips the step where Emacs asks the user whether they are sure about loading the theme.

Consider adding code like the above to the user configuration file, such as init.el.

NOTE: If you plan on using the ef-themes-post-load-hook, the above method will not work. Instead, you need to load the theme from your init file with ef-themes-select (Commands to load an Ef theme). For example:

;; like `load-theme' but also call `ef-themes-post-load-hook'
(ef-themes-select 'ef-summer)

7. Commands to load an Ef theme

The commands mentioned herein call ef-themes-post-load-hook at the end. This is for advanced users who want to trigger some code after an Ef theme is loaded (Use colors from the active Ef theme). The same goes for ef-themes-toggle (Toggle between two Ef themes).

A theme-agnostic hook for theme loading.

The themes can also be loaded interactively. The command ef-themes-select (call it with M-x) prompts with minibuffer completion for a theme among the collection of items we provide. It then loads the selected theme. Internally, ef-themes-select takes care to disable any other Ef theme, though it does not disable other themes. This is by design to let users maintain theme blending when they want it. Otherwise, the user is encouraged to disable all other themes and stick with the Ef themes:

(mapc #'disable-theme custom-enabled-themes)

The ef-themes-select command can also be called from the user’s init file to load the theme of their choice (Loading a theme). For example:

;; like `load-theme' but also call `ef-themes-post-load-hook'
(ef-themes-select 'ef-summer)

The command ef-themes-load-random is for those who appreciate a bit of serendipity in their life. When call interactively with M-x it loads a random theme from the Ef themes collection. The selection excludes the current Ef theme. Calling ef-themes-load-random with a prefix argument (C-u by default) makes the command limit the random selection to either light or dark themes. The user is prompted at the minibuffer to pick among the two sets.

The ef-themes-load-random can also be called from Lisp (e.g. from the init.el file):

(ef-themes-load-random)

This has the effect of loading an Ef theme at random, as described above. It is also possible to limit the set with either of those:

;; Load a light Ef theme at random
(ef-themes-load-random 'light)

;; Load a dark Ef theme at random
(ef-themes-load-random 'dark)

The author of the Ef themes likes to check with their operating system to determine if the desktop environment outside of Emacs is using a light/dark theme and then loads an appropriate Ef theme at random:

;; Check GNOME's gsettings database for the dark theme preference.  If
;; it is enabled, we want to load a dark Ef theme at random.  Otherwise
;; we load a random light theme.
(if (string-match-p
     "dark"
     (shell-command-to-string "gsettings get org.gnome.desktop.interface color-scheme"))
    (ef-themes-load-random 'dark)
  (ef-themes-load-random 'light))

8. Preview theme colors

The command ef-themes-preview-colors uses minibuffer completion to select an item from the Ef themes and then produces a buffer with previews of its color palette entries. The buffer has a naming scheme which reflects the given choice, like ef-summer-preview-colors for the ef-summer theme.

The command ef-themes-preview-colors-current skips the minibuffer selection process and just produces a preview for the current Ef theme.

9. Use colors from the active Ef theme

Advanced users may want to call color variables from the palette of the active Ef theme. The macro ef-themes-with-colors supplies those to any form called inside of it. For example:

(ef-themes-with-colors
  (list bg-main fg-main bg-mode-line cursor))
;; => ("#fff2f3" "#5f456f" "#ffa4dc" "#cf0090")

The above return value is for ef-summer when that is the active Ef theme. Switching to another theme and evaluating this code anew will give us the relevant results for that theme. The same with ef-winter:

(ef-themes-with-colors
  (list bg-main fg-main bg-mode-line cursor))
;; => ("#0f0b15" "#b8c6d5" "#5f1f5f" "#ff6ff0")

Do-It-Yourself customizations.

The palette of each Ef theme is considered stable. No removals shall be made. Though please note that some tweaks to individual hues or color mapping are still possible. At any rate, we will not outright break any code that uses ef-themes-with-colors.

10. Do-It-Yourself customizations

This section documents how the user can further tweak the Ef themes to their liking.

10.1. The general approach to advanced DIY changes

When the user wants to customize Emacs faces there are two considerations they need to make if they care about robustness:

  1. Do not hardcode color values, but instead use the relevant variables from the Ef themes.
  2. Make the changes persist through theme changes between the Ef themes collection.

For point 1 we provide the ef-themes-with-colors macro, while for point 2 we have the ef-themes-post-load-hook.

Use colors from the active Ef theme.

Commands to load an Ef theme.

A theme-agnostic hook for theme loading.

We need to wrap our code in the ef-themes-with-colors and declare it as a function which we then add to the hook. Here we show the general approach of putting those pieces together.

To customize faces we use the built-in custom-set-faces. The value it accepts has the same syntax as that found in ef-themes.el, specifically the ef-themes-faces constant. It thus is easy to copy lines from there and tweak them. Let’s pick a couple of font-lock faces (used in all programming modes, among others):

(defun my-ef-themes-custom-faces ()
  "My customizations on top of the Ef themes.
This function is added to the `ef-themes-post-load-hook'."
  (ef-themes-with-colors
    (custom-set-faces
     ;; These are the default specifications
     `(font-lock-comment-face ((,c :inherit italic :foreground ,comment)))
     `(font-lock-variable-name-face ((,c :foreground ,variable))))))

;; Using the hook lets our changes persist when we use the commands
;; `ef-themes-toggle', `ef-themes-select', and `ef-themes-load-random'.
(add-hook 'ef-themes-post-load-hook #'my-ef-themes-custom-faces)

Each item in the Ef themes collection has its own color mapping. So the color value of the comment variable will differ from theme-to-theme. For our purposes, we make variables look like comments and comments like variables:

(defun my-ef-themes-custom-faces ()
  "My customizations on top of the Ef themes.
This function is added to the `ef-themes-post-load-hook'."
  (ef-themes-with-colors
    (custom-set-faces
     `(font-lock-comment-face ((,c :foreground ,variable)))
     `(font-lock-variable-name-face ((,c :inherit italic :foreground ,comment))))))

;; Using the hook lets our changes persist when we use the commands
;; `ef-themes-toggle', `ef-themes-select', and `ef-themes-load-random'.
(add-hook 'ef-themes-post-load-hook #'my-ef-themes-custom-faces)

All changes take effect when a theme is loaded again. As such, it is better to use ef-themes-select at startup so that the function added to the hook gets applied properly upon first load. Like this:

(defun my-ef-themes-custom-faces ()
  "My customizations on top of the Ef themes.
This function is added to the `ef-themes-post-load-hook'."
  (ef-themes-with-colors
    (custom-set-faces
     `(font-lock-comment-face ((,c :foreground ,variable)))
     `(font-lock-variable-name-face ((,c :inherit italic :foreground ,comment))))))

;; Using the hook lets our changes persist when we use the commands
;; `ef-themes-toggle', `ef-themes-select', and `ef-themes-load-random'.
(add-hook 'ef-themes-post-load-hook #'my-ef-themes-custom-faces)

;; Load the theme and run `ef-themes-post-load-hook'
(ef-themes-select 'ef-summer) ; Instead of (load-theme 'ef-summer :no-confirm)

Please contact us if you have specific questions about this mechanism. We are willing to help and shall provide comprehensive documentation where necessary.

10.2. A theme-agnostic hook for theme loading

The themes are designed with the intent to be useful to Emacs users of varying skill levels, from beginners to experts. This means that we try to make things easier by not expecting anyone reading this document to be proficient in Emacs Lisp or programming in general.

Such a case is with the use of the ef-themes-post-load-hook, which is called after the evaluation of any of the commands we provide for loading a theme (Commands to load an Ef theme). We recommend using that hook for advanced customizations, because (1) we know for sure that it is available once the themes are loaded, and (2) anyone consulting this manual, especially the sections on enabling and loading the themes, will be in a good position to benefit from that hook.

Advanced users who have a need to switch between the Ef themes and other items (e.g. my modus-themes) will find that such a hook does not meet their requirements: it only works with the Ef themes and only with the aforementioned functions.

A theme-agnostic setup can be configured thus:

(defvar after-enable-theme-hook nil
   "Normal hook run after enabling a theme.")

(defun run-after-enable-theme-hook (&rest _args)
   "Run `after-enable-theme-hook'."
   (run-hooks 'after-enable-theme-hook))

(advice-add 'enable-theme :after #'run-after-enable-theme-hook)

This creates the after-enable-theme-hook and makes it run after each call to enable-theme, which means that it will work for all themes and also has the benefit that it does not depend on functions such as ef-themes-select and the others mentioned in this manual. The function enable-theme is called internally by load-theme, so the hook works everywhere.

In this document, we always mention ef-themes-post-load-hook though the user can replace it with after-enable-theme-hook should they need to.

10.3. Add support for hl-todo

The hl-todo package provides the user option hl-todo-keyword-faces: it specifies an association list of (KEYWORD . COLOR-VALUE) pairs. There are no faces, which the theme could style seamlessly. As such, it rests on the user to specify appropriate color values. This can be done either by hardcoding colors, which is inefficient, or by using the macro ef-themes-with-colors (The general approach to DIY changes). Here we show the latter method.

(defun my-ef-themes-hl-todo-faces ()
  "Configure `hl-todo-keyword-faces' with Ef themes colors.
The exact color values are taken from the active Ef theme."
  (ef-themes-with-colors
    (setq hl-todo-keyword-faces
          `(("HOLD" . ,yellow)
            ("TODO" . ,red)
            ("NEXT" . ,blue)
            ("THEM" . ,magenta)
            ("PROG" . ,cyan-warmer)
            ("OKAY" . ,green-warmer)
            ("DONT" . ,yellow-warmer)
            ("FAIL" . ,red-warmer)
            ("BUG" . ,red-warmer)
            ("DONE" . ,green)
            ("NOTE" . ,blue-warmer)
            ("KLUDGE" . ,cyan)
            ("HACK" . ,cyan)
            ("TEMP" . ,red)
            ("FIXME" . ,red-warmer)
            ("XXX+" . ,red-warmer)
            ("REVIEW" . ,red)
            ("DEPRECATED" . ,yellow)))))

(add-hook 'ef-themes-post-load-hook #'my-ef-themes-hl-todo-faces)

To find the names of the color variables, the user can rely on the commands for previewing the palette (Preview theme colors).

10.4. Make the modeline like the modus-themes default

The Ef themes do not use a :box attribute for their mode lines, while the active one has an accented background. Users may prefer the approach that my modus-themes follow by default, where both active and inactive mode lines use shades of gray and have a border around them.

Try something like this, using the approach we have already explained about ef-themes-with-colors (The general approach to DIY changes):

(defun my-ef-themes-mode-line ()
  "Tweak the style of the mode lines."
  (ef-themes-with-colors
    (custom-set-faces
     `(mode-line ((,c :background ,bg-active :foreground ,fg-main :box (:line-width 1 :color ,fg-dim))))
     `(mode-line-inactive ((,c :box (:line-width 1 :color ,bg-active)))))))

(add-hook 'ef-themes-post-load-hook #'my-ef-themes-mode-line)

If you want the active mode line to retain its accented background but also have a border around it, change this line from the above snippet:

(mode-line ((,c :background ,bg-active :foreground ,fg-main :box (:line-width 1 :color ,fg-dim))))

To this:

`(mode-line ((,c :background ,bg-mode-line :foreground ,fg-mode-line :box (:line-width 1 :color ,fg-dim))))

10.5. Configure bold and italic faces

The Ef themes do not hardcode a :weight or :slant attribute in the faces they cover. Instead, they configure the generic faces called bold and italic to use the appropriate styles and then instruct all relevant faces that require emphasis to inherit from them.

This practically means that users can change the particularities of what it means for a construct to be bold/italic, by tweaking the bold and italic faces. Cases where that can be useful include:

  • The default typeface does not have a variant with slanted glyphs (e.g. Fira Mono/Code as of this writing on 2022-08-23), so the user wants to add another family for the italics, such as Hack.
  • The typeface of choice provides a multitude of weights and the user prefers the light one by default. To prevent the bold weight from being too heavy compared to the light one, they opt to make bold use a semibold weight.
  • The typeface distinguishes between oblique and italic forms by providing different font variants (the former are just slanted versions of the upright forms, while the latter have distinguishing features as well). In this case, the user wants to specify the font that applies to the italic face.

To achieve those effects, one must first be sure that the fonts they use have support for those features.

In this example, we set the default font family to Fira Code, while we choose to render italics in the Hack typeface (obviously one needs to pick fonts that work in tandem):

(set-face-attribute 'default nil :family "Fira Code" :height 110)
(set-face-attribute 'italic nil :family "Hack")

And here we play with different weights, using Source Code Pro:

(set-face-attribute 'default nil :family "Source Code Pro" :height 110 :weight 'light)
(set-face-attribute 'bold nil :weight 'semibold)

To reset the font family, one can use this:

(set-face-attribute 'italic nil :family 'unspecified)

Consider the fontaine package on GNU ELPA (by Protesilaos) which provides the means to configure font families via faces.

10.6. Tweak org-modern timestamps

The org-modern package uses faces and text properties to make Org buffers more aesthetically pleasing. It affects tables, timestamps, lists, headings, and more.

In previous versions of the Ef themes, we mistakenly affected one of its faces: the org-modern-label. It changed the intended looks and prevented the user option org-modern-label-border from having its desired effect. As such, we no longer override that face.

Users who were used to the previous design and who generally do not configure the user options of org-modern may thus notice a change in how clocktables (or generally tables with timestamps) are aligned. The simplest solution is to instruct the mode to not prettify timestamps, by setting the user option org-modern-timestamp to nil. For example, by adding this to the init file:

(setq org-modern-timestamp nil)

Alignment in tables will also depend on the use of proportionately spaced fonts. Enable the relevant option to work with those without any further trouble (Enable mixed fonts).

For any further issues, you are welcome to ask for help.

10.7. Tweak goto-address-mode faces

The built-in goto-address-mode uses heuristics to identify URLs and email addresses in the current buffer. It then applies a face to them to change their style. Some packages, such as notmuch, use this minor-mode automatically.

The faces are not declared with defface, meaning that it is better that the theme does not modify them. The user is thus encouraged to consider including this in their setup:

(setq goto-address-url-face 'link
      goto-address-url-mouse-face 'highlight
      goto-address-mail-face 'link
      goto-address-mail-mouse-face 'highlight)

My personal preference is to set goto-address-mail-face to nil, because it otherwise adds too much visual noise to the buffer (email addresses stand out more, due to the use of the uncommon @ caharacter but also because they are often enclosed in angled brackets).

11. Supported packages or face groups

The ef-themes will only ever support a curated list of packages based on my judgement (Packages that are hard to support). Nevertheless, the list of explicitly or implicitly supported packages already covers everything most users need.

11.1. Explicitly supported packages or face groups

  • all basic faces
  • all-the-icons
  • all-the-icons-dired
  • all-the-icons-ibuffer
  • ansi-color
  • auctex
  • bongo
  • bookmark
  • calendar and diary
  • change-log and log-view (part of VC)
  • chart
  • company
  • compilation
  • completions
  • consult
  • custom (M-x customize)
  • denote
  • dictionary
  • diff-hl
  • diff-mode
  • dired
  • dired-subtree
  • diredfl
  • dirvish
  • display-fill-column-indicator-mode
  • doom-modeline
  • ediff
  • eldoc
  • elfeed
  • embark
  • epa
  • eshell
  • eww
  • font-lock
  • git-commit
  • git-rebase
  • gnus
  • image-dired
  • info
  • isearch, occur, query-replace
  • keycast
  • lin
  • line numbers (display-line-numbers-mode and global variant)
  • magit
  • man
  • marginalia
  • markdown-mode
  • messages
  • mode-line
  • mu4e
  • notmuch
  • orderless
  • org
  • org-habit
  • org-modern
  • outline-mode
  • outline-minor-faces
  • package (M-x list-packages)
  • pulsar
  • pulse
  • rainbow-delimiters
  • rcirc
  • recursion-indicator
  • regexp-builder (re-builder)
  • ruler-mode
  • selectrum
  • shell-script-mode (sh-mode)
  • show-paren-mode
  • shr
  • smerge
  • tab-bar-mode
  • tab-line-mode
  • tempel
  • term
  • textsec
  • transient
  • vc (vc-dir.el, vc-hooks.el)
  • vertico
  • wgrep
  • which-function-mode
  • whitespace-mode
  • widget
  • woman

11.2. Implicitly supported packages or face groups

Those are known to work with the Ef themes either because their colors are appropriate or because they inherit from basic faces which the themes already cover:

  • apropos
  • corfu
  • dim-autoload
  • flycheck
  • flymake
  • flyspell
  • hl-todo
  • icomplete
  • ido
  • multiple-cursors
  • paren-face
  • which-key
  • xref

Note that “implicitly supported” does not mean that they always fit in perfectly. If there are refinements we need to made, then we need to intervene (Explicitly supported packages or face groups).

11.3. Packages that are hard to support

These are difficult to support due to their (i) incompatibility with the design of the ef-themes, (ii) complexity or multiple points of entry, (iii) external dependencies, (iv) existence of better alternatives in my opinion, or (v) inconsiderate use of color out-of-the-box and implicit unwillingness to be good Emacs citizens:

avy
its UI is prone to visual breakage and is hard to style correctly.
calibredb
has an external dependency that I don’t use.
ctrlf
use the built-in isearch or the consult-line command of consult.
dired+
it is complex and makes inconsiderate use of color.
ein (Emacs IPython Notebook)
external dependency that I don’t use.
elfeed-goodies
depends on powerline
ement.el
has an external dependency that I don’t use.
helm
it is complex and makes inconsiderate use of color. Prefer the vertico, consult, and embark packages.
info+
it is complex and makes inconsiderate use of color.
ivy/counsel/swiper
use the vertico, consult, and embark packages which are designed to be compatible with standard Emacs mechanisms and are modular.
lsp-mode
has external dependencies that I don’t use.
powerline
requires too many shades of background and generally violates our expectation of how the mode-line is supposed to look by placing the designated default background in unexpected places.
solaire
in principle, it is incompatible with practically every theme that is not designed around it. Emacs does not distinguish between “UI” and “syntax” buffers.
spaceline
same as powerline.
sx
has an external dependency that I don’t use.
telega
has an external dependency that I don’t use (I don’t even have a smartphone).
telephone-line
same as powerline.
treemacs
it has too many dependencies and does too many things.
web-mode
I don’t use all those Web technologies and cannot test this properly without support from an expert. It also defines lots of faces that hardcode color values for no good reason.

The above list is non-exhaustive though you get the idea.

12. Principles

  • No customization options that affect the coloration of individual components! Either you like them or you don’t. To change the attributes of individual faces, it is better to do it in user-level configurations (Do-It-Yourself customizations). Report the issue and we can help with the relevant code. Providing customizations that refashion a wide set of themes is not maintainable.
  • Curated list of supported faces (Supported packages or face groups). I will only cover what I use and/or know is in a well-maintained state. Styling a package requires a lot of work as one must (i) know how the package works, (ii) see all its interfaces in action, (iii) make sure that the color combinations look consistent with the rest of the theme.
  • Minimum contrast ratio of 4.5:1 against the main background (WCAG AA standard). Use my modus-themes package (also built into Emacs 28 or higher) if you need top-class accessibility.
  • If two elements are functionally different, the theme must render this fact conspicuous (Let Org tags inherit the heading color?).
  • Respect the decisions of the upstream package provider or, else, do not make weird things with faces. We only override the design choice of a package if it is necessary.
  • When there is an inescapable trade-off between usability and aesthetics, we will always opt for the former, without prejudice to the aforementioned principles.

12.1. Minimal VS maximal scope

The ef-themes are meant to be minimal in scope, as opposed to my modus-themes whose accessibility requirements make them maximalist by necessity. The modus-themes are such because:

  1. Accessibility is not a one-size-fits-all. Customisation options are necessary to empower users.
  2. Accessibility is as good as its weakest link. If the user spends all day using FOO package, it needs to be perfectly legible, otherwise the whole theme fails to deliver on its promise.

The ef-themes can afford to be minimal because they do not have such a lofty accessibility target.

13. FAQ

13.1. What does Ef mean?

“Ef” is a Greek word (ευ), commonly used as a prefix to denote that something is good, nice, and/or easy. For example, eftopia (ευτοπία) is the opposite of dystopia (δυστοπία): a good place as opposed to a bad place.

13.2. Will you stop using the modus-themes?

No. For my workflow, accessibility is the most important quality. The modus-themes will remain my default choice.

13.3. Then why develop the ef-themes?

Because I think that users deserve “pretty” themes that (i) do make some considerations for legibility, and (ii) are not designed on a whimsy.

The ef-themes are my answer to those who (i) like my modus-themes, (ii) want something with a bit more flair, and (iii) are fine with a bit more relaxed accessibility target.

13.4. Let Org tags inherit the heading color?

Upstream Org defines tags in headings to have the same color as the rest of the heading’s text. However, tags are a distinct component of the heading as noted in the doc string of the org-get-heading function. Tags also are functionally different than the ordinary text of the heading: they are a clickable link/button. It thus is a matter of usability to render this distinction clear at the visual level: I do not agree with upstream Org’s design decision.

Normally, we would style a link to have an underline. However, this design does not look right in headings (as it doesn’t look right in, e.g., the headings in a listing of emails or the unread items in the Elfeed list of entries). We thus have to go with the next option, which is to use a distinct foreground color that differentiates the tag from its context, while accounting for theme-wide usability and consistency.

The overarching principle is that when two things function differently, they have to look apart even if the difference is small.

The assumption that tags are right-aligned (per Org’s default behaviour) does not hold, as there exists a user option to disable this effect: org-auto-align-tags. The author of the ef-themes uses this option because the way Org performs this alignment using literal spaces does not work properly with (i) proportionately spaced fonts, (ii) varying heading heights, (iii) different levels of indentation. Realigning tags by inserting spaces also creates noise in version-controlled files, which is undesirable.

13.5. Add something like Nord or Zenburn?

In general, I am not against the idea of drawing inspiration from other themes. Note though that every item in the ef-themes collection is designed from scratch to work in accordance with the principles of this project (Principles).

Each palette is an original implementation. The six basic hues of red, green, blue, yellow, magenta, cyan are implemented as quartets of a base, warmer, cooler, and faint variants.

All themes have their own color mapping, which is conducted in accordance with the exact values of the aforementioned hues and their innate relations.

Copying another project’s palette is generally not possible or not desirable, not even if that is my modus-themes (they, too, have a different set of requirements).

Furthermore, trying to mimic another theme generally is an exercise with prior constraints, as we are always labouring under the expectation of remaining faithful to the original. This can lead to awkward compromises and sub-optimal choices, which make no sense for a project with opinionanted design principles.

14. Acknowledgements

This project is meant to be a collective effort. Every bit of help matters.

Author/maintainer
Protesilaos Stavrou.
Contributions to code or the manual
Alex Lu, Christopher League, Philip Kaludercic.
Ideas and/or user feedback
Alan Schmitt, Anthony Chavez, Daniel Mendler, Iris Garcia, Jean-Philippe Gagné Guay, Jonas Collberg, Spike-Leung, Steve Molitor, Summer Emacs, Sven Seebeck, Zoltán Király.

15. GNU Free Documentation License


                GNU Free Documentation License
                 Version 1.3, 3 November 2008


 Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
     
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