fontaine.el: Set font configurations using presets

This manual, written by Protesilaos Stavrou, describes the customization options for fontaine (or fontaine.el), and provides every other piece of information pertinent to it.

The documentation furnished herein corresponds to stable version {{{stable-version}}}, released on {{{release-date}}}. 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 {{{development-version}}}.

Homepage: https://protesilaos.com/emacs/fontaine.
Change log: https://protesilaos.com/emacs/fontaine-changelog.
Git repository: https://git.sr.ht/~protesilaos/fontaine.
Mailing list: https://lists.sr.ht/~protesilaos/fontaine.

1 COPYING

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 Overview

Fontaine lets the user specify presets of font configurations and set them on demand on graphical Emacs frames. The user option fontaine-presets holds all such presets.

Presets consist of a list of properties that govern the family, weight, and height of the faces default, fixed-pitch, variable-pitch, bold, and italic. Each preset is identified by a user-defined symbol as the car of a property list. It looks like this (check the default value of fontaine-presets for how everything is pieced together):

(regular
 :default-family "Hack"
 :default-weight normal
 :default-height 100
 :fixed-pitch-family "Fira Code"
 :fixed-pitch-weight nil ; falls back to :default-weight
 :fixed-pitch-height 1.0
 :variable-pitch-family "Noto Sans"
 :variable-pitch-weight normal
 :variable-pitch-height 1.0
 :bold-family nil ; use whatever the underlying face has
 :bold-weight bold
 :italic-family "Source Code Pro"
 :italic-slant italic
 :line-spacing 1)

The doc string of fontaine-presets explains all properties in detail and documents some important caveats or information about font settings in Emacs.

Shared and implicit fallback values for presets.

The command fontaine-set-preset applies the desired preset. If there is only one available, it implements it outright. Otherwise it produces a minibuffer prompt with completion among the available presets. When called from Lisp, the fontaine-set-preset requires a PRESET argument, such as:

(fontaine-set-preset 'regular)

The default behaviour of fontaine-set-preset is to change fonts across all graphical frames. The user can, however, limit the changes to a given frame. For interactive use, this is done by invoking the command with a universal prefix argument (C-u by default), which changes fonts only in the current frame. When used in Lisp, the FRAME argument can be a frame object (satisfies framep) or a non-nil value: the former applies the effects to the given object, while the latter means the current frame and thus is the same as interactively supplying the prefix argument.

The command fontaine-set-face-font prompts with completion for a face and then asks the user to specify the value of the relevant properties. Preferred font families can be defined in the user option fontaine-font-families, otherwise Fontaine will try to find suitable options among the fonts installed on the system (not always reliable, depending on the Emacs build and environment it runs in). The list of faces to choose from is the same as that implied by the fontaine-presets. Properties to change and their respective values will depend on the face. For example, the default face requires a natural number for its height attribute, whereas every other face needs a floating point (understood as a multiple of the default height). This command is for interactive use only and is supposed to be used for previewing certain styles before eventually codifying them as presets.

Changing the bold and italic faces only has a noticeable effect if the underlying theme does not hardcode a weight and slant but inherits from those faces instead (e.g. the modus-themes).

The fontaine-set-face-font also accepts an optional FRAME argument, which is the same as what was described above for fontaine-set-preset.

The latest value of fontaine-set-preset is stored in a file whose location is defined in fontaine-latest-state-file (normally part of the .emacs.d directory). Saving is done by the function fontaine-store-latest-preset, which should be assigned to a hook (e.g. kill-emacs-hook). To restore that value, the user can call the function fontaine-restore-latest-preset (such as by adding it to their init file).

For users of the no-littering package, fontaine-latest-state-file is not stored in their .emacs.d, but in a standard directory instead: https://github.com/emacscollective/no-littering.

As for the name of this package, it is the French word for “fountain” which, in turn, is what the font or source is. However, I will not blame you if you can only interpret it as a descriptive acronym: FONTs Are Irrelevant in Non-graphical Emacs (because that is actually true).

2.1 Shared and implicit fallback values for presets

The user option fontaine-presets may look like this (its default value):

(setq fontaine-presets
      '((regular
         :default-family "Hack"
         :default-weight normal
         :default-height 100
         :fixed-pitch-family "Fira Code"
         :fixed-pitch-weight nil ; falls back to :default-weight
         :fixed-pitch-height 1.0
         :variable-pitch-family "Noto Sans"
         :variable-pitch-weight normal
         :variable-pitch-height 1.0
         :bold-family nil ; use whatever the underlying face has
         :bold-weight bold
         :italic-family "Source Code Pro"
         :italic-slant italic
         :line-spacing 1)
        (large
         :default-family "Iosevka"
         :default-weight normal
         :default-height 150
         :fixed-pitch-family nil ; falls back to :default-family
         :fixed-pitch-weight nil ; falls back to :default-weight
         :fixed-pitch-height 1.0
         :variable-pitch-family "FiraGO"
         :variable-pitch-weight normal
         :variable-pitch-height 1.05
         :bold-family nil ; use whatever the underlying face has
         :bold-weight bold
         :italic-family nil ; use whatever the underlying face has
         :italic-slant italic
         :line-spacing 1)))

Notice that not all properties need to be specified, as they have reasonable fallback values. The above can be written thus (removed lines are left empty for didactic purposes):

(setq fontaine-presets
      '((regular
         :default-family "Hack"

         :default-height 100
         :fixed-pitch-family "Fira Code"


         :variable-pitch-family "Noto Sans"




         :italic-family "Source Code Pro"

         :line-spacing 1)
        (large
         :default-family "Iosevka"

         :default-height 150



         :variable-pitch-family "FiraGO"






         :line-spacing 1)))

Without the empty lines, we have this, which yields the same results as the first example:

(setq fontaine-presets
      '((regular
         :default-family "Hack"
         :default-height 100
         :fixed-pitch-family "Fira Code"
         :variable-pitch-family "Noto Sans"
         :italic-family "Source Code Pro"
         :line-spacing 1)
        (large
         :default-family "Iosevka"
         :default-height 150
         :variable-pitch-family "FiraGO"
         :line-spacing 1)))

We call the properties of the removed lines “implicit fallback values”.

This already shows us that the value of fontaine-presets does not need to be extensive. To further improve its conciseness, it accepts a special preset that provides a list of “shared fallback properties”: the t preset. This one is used to define properties that are common to multiple presets, such as the regular and large we have illustrated thus far. Here is how verbose presets can be expressed succinctly:

;; Notice the duplication of properties and how we will avoid it.
(setq fontaine-presets
      '((regular
         :default-family "Iosevka Comfy"
         :default-weight normal
         :default-height 100
         :fixed-pitch-family nil ; falls back to :default-family
         :fixed-pitch-weight nil ; falls back to :default-weight
         :fixed-pitch-height 1.0
         :variable-pitch-family "FiraGO"
         :variable-pitch-weight normal
         :variable-pitch-height 1.05
         :bold-family nil ; use whatever the underlying face has
         :bold-weight bold
         :italic-family nil
         :italic-slant italic
         :line-spacing nil)
        (medium
         :default-family "Iosevka Comfy"
         :default-weight semilight
         :default-height 140
         :fixed-pitch-family nil ; falls back to :default-family
         :fixed-pitch-weight nil ; falls back to :default-weight
         :fixed-pitch-height 1.0
         :variable-pitch-family "FiraGO"
         :variable-pitch-weight normal
         :variable-pitch-height 1.05
         :bold-family nil ; use whatever the underlying face has
         :bold-weight bold
         :italic-family nil
         :italic-slant italic
         :line-spacing nil)
        (large
         :default-family "Iosevka Comfy"
         :default-weight semilight
         :default-height 180
         :fixed-pitch-family nil ; falls back to :default-family
         :fixed-pitch-weight nil ; falls back to :default-weight
         :fixed-pitch-height 1.0
         :variable-pitch-family "FiraGO"
         :variable-pitch-weight normal
         :variable-pitch-height 1.05
         :bold-family nil ; use whatever the underlying face has
         :bold-weight extrabold
         :italic-family nil
         :italic-slant italic
         :line-spacing nil)))

(setq fontaine-presets
      '((regular
         :default-height 100)
        (medium
         :default-weight semilight
         :default-height 140)
        (large
         :default-weight semilight
         :default-height 180
         :bold-weight extrabold)
        (t ; our shared fallback properties
         :default-family "Iosevka Comfy"
         :default-weight normal
         ;; :default-height 100
         :fixed-pitch-family nil ; falls back to :default-family
         :fixed-pitch-weight nil ; falls back to :default-weight
         :fixed-pitch-height 1.0
         :variable-pitch-family "FiraGO"
         :variable-pitch-weight normal
         :variable-pitch-height 1.05
         :bold-family nil ; use whatever the underlying face has
         :bold-weight bold
         :italic-family nil
         :italic-slant italic
         :line-spacing nil)))

The t preset does not need to explicitly cover all properties. It can rely on the aforementioned “implicit fallback values” to further reduce its verbosity (though the user can always write all properties if they intend to change their values). We then have this transformation:

;; The verbose form
(setq fontaine-presets
      '((regular
         :default-height 100)
        (medium
         :default-weight semilight
         :default-height 140)
        (large
         :default-weight semilight
         :default-height 180
         :bold-weight extrabold)
        (t ; our shared fallback properties
         :default-family "Iosevka Comfy"
         :default-weight normal
         ;; :default-height 100
         :fixed-pitch-family nil ; falls back to :default-family
         :fixed-pitch-weight nil ; falls back to :default-weight
         :fixed-pitch-height 1.0
         :variable-pitch-family "FiraGO"
         :variable-pitch-weight normal
         :variable-pitch-height 1.05
         :bold-family nil ; use whatever the underlying face has
         :bold-weight bold
         :italic-family nil
         :italic-slant italic
         :line-spacing nil)))

;; The concise one which relies on "implicit fallback values"
(setq fontaine-presets
      '((regular
         :default-height 100)
        (medium
         :default-weight semilight
         :default-height 140)
        (large
         :default-weight semilight
         :default-height 180
         :bold-weight extrabold)
        (t ; our shared fallback properties
         :default-family "Iosevka Comfy"
         :default-weight normal
         :variable-pitch-family "FiraGO"
         :variable-pitch-height 1.05)))

3 Installation

3.1 GNU ELPA package

The package is available as fontaine. 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/.

3.2 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 "fontaine"
git clone https://git.sr.ht/~protesilaos/fontaine fontaine

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/fontaine")

Everything is in place to set up the package.

4 Sample configuration

Remember to read the relevant doc strings.

(require 'fontaine)

(setq fontaine-latest-state-file
      (locate-user-emacs-file "fontaine-latest-state.eld"))

(setq fontaine-presets
      '((regular
         :default-family "Hack"
         :default-weight normal
         :default-height 100
         :fixed-pitch-family "Fira Code"
         :fixed-pitch-weight nil ; falls back to :default-weight
         :fixed-pitch-height 1.0
         :variable-pitch-family "Noto Sans"
         :variable-pitch-weight normal
         :variable-pitch-height 1.0
         :bold-family nil ; use whatever the underlying face has
         :bold-weight bold
         :italic-family "Source Code Pro"
         :italic-slant italic
         :line-spacing 1)
        (large
         :default-family "Iosevka"
         :default-weight normal
         :default-height 150
         :fixed-pitch-family nil ; falls back to :default-family
         :fixed-pitch-weight nil ; falls back to :default-weight
         :fixed-pitch-height 1.0
         :variable-pitch-family "FiraGO"
         :variable-pitch-weight normal
         :variable-pitch-height 1.05
         :bold-family nil ; use whatever the underlying face has
         :bold-weight bold
         :italic-family nil ; use whatever the underlying face has
         :italic-slant italic
         :line-spacing 1)))

;; Recover last preset or fall back to desired style from
;; `fontaine-presets'.
(fontaine-set-preset (or (fontaine-restore-latest-preset) 'regular))

;; The other side of `fontaine-restore-latest-preset'.
(add-hook 'kill-emacs-hook #'fontaine-store-latest-preset)

;; fontaine does not define any key bindings.  This is just a sample that
;; respects the key binding conventions.  Evaluate:
;;
;;     (info "(elisp) Key Binding Conventions")
(define-key global-map (kbd "C-c f") #'fontaine-set-preset)
(define-key global-map (kbd "C-c F") #'fontaine-set-face-font)

5 Acknowledgements

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

Author/maintainer: Protesilaos Stavrou.
Contributions to the code or manual: Christopher League, Eli Zaretskii.
Ideas and user feedback: Ted Reed.

6 GNU Free Documentation License

flocks / fontaine