Correct alignment of in-buffer settings (and properties) when using variable-width font in org-mode

Question

on the left side I'm using a variable-pitch font "Charis SIL Compact" and on the right side a fixed-pitch monospace font "Hack Regular."

As expected, the monospace "Hack" font aligns the items properly in the front matter, see the right side. I think that's because monospaced fonts always have the same spacing between letters. Right?

However, I tried setting some exceptions to have the front matter always displayed in monospace font. Unfortunately, it doesn't work this way:

(set-face-attribute 'fixed-pitch nil :font "DejaVu Sans Mono")
  (defun my/org-fixed-pitch ()
    (set-face-attribute 'org-meta-line nil :inherit 'fixed-pitch)
    (set-face-attribute 'org-document-info nil :inherit 'fixed-pitch)
    (set-face-attribute 'org-document-info-keyword :inherit 'fixed-pitch)))

and then I call this function when org starts. Sure, now the document info and keywords display in a monospace font but the spacing is still messed up. I was wondering if there is a way to target the front matter as a whole? The org-meta-line should target the whole #+xxxx: xyz line but it doesn't seem to take any effect.

Answer 1

This has been bugging me for a long time too!

org-fontify-meta-lines-and-blocks-1 is responsible for setting the fonts of the meta lines. Looking at its source one can see that for keywords in ("+title:" "+subtitle:" "+author:" "+email:" "+date:") it sets the font org-document-info-keyword for the keyword itself, while the values get fonts org-document-title or org-document-info. It doesn't fontify the whitespace between the keyword and the value though and this is why we have misalignment.

On the other hand, lines with keywords not in the above list (the last cond case in the code) get fontified fully with face org-meta-line. For these there is no alignment problem (try this).

One way to address this is to overwrite (e.g. using :override advice) org-fontify-meta-lines-and-blocks-1 with a version which provides the desired START and END arguments in the calls to add-text-properties. This is a very long function though...

Another way is to make use of the hooks provided by org-set-font-lock-defaults (which indirectly calls org-fontify-meta-lines-and-blocks-1) to override the defaults. org-font-lock-hook can be used to insert defaults at the beginning of the list of defaults, which is called org-font-lock-extra-keywords, and org-font-lock-set-keywords-hook can modify this list arbitrarily before it is passed to font-lock-defaults. doom-themes-enable-org-fontification provides a good example of the latter approach.

A third way is to make use of the function font-lock-add-keywords. Using this approach, with the following in my init.el the header is properly aligned:

(font-lock-add-keywords
 'org-mode
 '(("^#\\+\\(title\\|TITLE\\):\\(.*\\)$"
    2 'org-document-title t)
   ("^#\\+\\(subtitle\\|author\\|email\\|date\\):\\(.*\\)$"
    2 'org-document-info t)
   ("^#\\+\\(SUBTITLE\\|AUTHOR\\|EMAIL\\|DATE\\):\\(.*\\)$"
    2 'org-document-info t))
 't)

(defun my-org-fixed-pitch ()
  (interactive)
  (set-face-attribute 'org-meta-line nil :inherit 'fixed-pitch)
  (set-face-attribute 'org-document-title nil :inherit 'fixed-pitch)
  (set-face-attribute 'org-document-info nil :inherit 'fixed-pitch)
  (set-face-attribute 'org-document-info-keyword nil :inherit 'fixed-pitch))

(add-hook 'org-mode-hook #'my-org-fixed-pitch)

Note that to actually align the header (i.e. set the right number of spaces) one can select it and then use M-x align-regexp RET <space> RET.

The same alignment issue occurs within property drawers and can be fixed similarly by adding (set-face-attribute 'org-special-keyword nil :inherit 'fixed-pitch) to my-org-fixed-pitch above and the following in init.el:

(defconst my-org-property-re "^\\(?4:[  ]*\\)\\(?1::\\(?2:\\S-+\\):\\)\\(?:\\(?6:\\(?3:$\\)\\)\\|\\(?6:[    ]+\\)\\(?3:.*?\\)\\)\\(?5:[     ]*\\)$"
  "Like `org-property-re' but adding one capture group.")

(font-lock-add-keywords
 'org-mode
 `((,my-org-property-re
    6 'org-special-keyword t))
 't)

Furthermore, I suspect a similar issue is behind the misalignment of paragraphs under headings that is visible in the left window of the image, and that persists even when one sets a fixed-pitch font for the headings.