Protesilaos Stavrou

Emacs: 'standard-themes' version 1.2.0

The standard-themes are a pair of light and dark themes for GNU Emacs. They emulate the out-of-the-box looks of Emacs (which technically do NOT constitute a theme) while bringing to them thematic consistency, customizability, and extensibility. In practice, the Standard themes take the default style of the font-lock and Org faces, complement it with a wider and hamronious colour palette, address many inconsistencies, and apply established semantic patterns across all interfaces by supporting a large number of packages.

Below are the release notes.

Support for palette overrides

It is now possible to override the palette of each Standard theme. This is the same feature that I implemented for the modus-themes, except it is a bit more limited in scope (the Modus themes are maximalist due to their accessibility target).

Overrides allow the user to tweak the presentation of either or both themes, such as to change the colour value of individual entries and/or remap how named colors are applied to semantic code constructs.

For example, the user can change what the exact value of blue-warmer is and then, say, make comments use a shade of green instead of red.

There are three user options to this end:

  • standard-themes-common-palette-overrides which covers both themes.
  • standard-dark-palette-overrides which concerns the dark theme.
  • standard-light-palette-overrides which is for the light theme.

The theme-specific overrides take precedence over the “common” ones.

The theme’s palette with named colors can be previewed with the commands standard-themes-preview-colors and standard-themes-preview-colors-current. When called with a universal prefix argument (C-u with default key bindings) these commands produce a preview of the semantic colour mappings (e.g. what colour applies to level 2 headings).

Use the preview as a reference to find entries to override. And consult the manual for the technicalities.

Thanks to Clemens Radermacher for fixing a mistake I made in the code that produces the palette previews.

Added the function standard-themes-get-color-value

It returns the colour value of named COLOR for the current Standard theme.

COLOR is a symbol that represents a named colour entry in the palette.

If the value is the name of another colour entry in the palette (so a mapping), recur until you find the underlying colour value.

With optional OVERRIDES as a non-nil value, account for palette overrides. Else use the default palette.

With optional THEME as a symbol among standard-themes-items, use the palette of that item. Else use the current Standard theme.

If COLOR is not present in the palette, return the unspecified symbol, which is safe when used as a face attribute’s value.

The manual provides this information and also links to relevant entries. The example it uses, with the standard-light as current:

;; Here we show the recursion of palette mappings.  In general, it is
;; better for the user to specify named colors to avoid possible
;; confusion with their configuration, though those still work as
;; expected.
(setq standard-themes-common-palette-overrides
      '((cursor red)
        (prompt cursor)
        (variable prompt)))

;; Ignore the overrides and get the original value.
(standard-themes-get-color-value 'variable)
;; => "#a0522d"

;; Read from the overrides and deal with any recursion to find the
;; underlying value.
(standard-themes-get-color-value 'variable :overrides)
;; => "#b3303a"

New user option standard-themes-disable-other-themes

This user option is set to t by default. This means that loading a Standard theme with the command standard-themes-toggle or the functions standard-theme-load-dark, standard-theme-load-light will disable all custom-enabled-themes.

When the value of this user option is nil, themes are loaded without disabling other entries outside their family. This retains the original (and in my opinion bad for most users) behaviour of Emacs where it blithely blends multiple enabled themes.

I consider the blending a bad default because it undoes the work of the designer and often leads to highly inaccessible and unpredictable combinations. Sure, experts can blend themes which is an argument in favour of making that behaviour opt-in.

Other changes

Acknowledgement

Thanks to Fritz Grabo who provided feedback via a private channel. With it, I was able to better understand the underlying patterns of the out-of-the-box Emacs faces and thus design the standard-themes accordingly. This information is shared with permission.

As a reminder, the Standard themes are an interpretation of the default Emacs faces (which technically are not a “theme”). I have expanded the effective palette with harmonious entries, made mappings that are consistent with the patterns found in some base faces, and extended support for lots of packages. At first sight, the Standard themes look like what you get with an unconfigured Emacs. Though make no mistake: they are far more detail-oriented.

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