Get font face under cursor in Emacs

Question

I've been developing my own custom color theme, and it'd be really useful if I could get a list of font-faces affecting the text under the cursor.

Something like Textmate's show current scope command.

That would save me the trouble of doing M-x customize-face and looking through available options, guessing at which one affects the current word I'm on.

Any ideas?

Solution 1

You can define what-face with this code:

(defun what-face (pos)
  (interactive "d")
  (let ((face (or (get-char-property (pos) 'read-face-name)
                  (get-char-property (pos) 'face))))
    (if face (message "Face: %s" face) (message "No face at %d" pos))))

After that,

M-x what-face

will print the face found at the current point.

(Thanks to thedz for pointing out that what-face wasn’t built in.)

Solution 2

what-cursor-position with a prefix argument shows the face under point, among other information.

Keyboard shortcut is C-u C-x =

Example output (the face property is shown in the last paragraph):

             position: 5356 of 25376 (21%), column: 4
            character: r (displayed as r) (codepoint 114, #o162, #x72)
    preferred charset: ascii (ASCII (ISO646 IRV))
code point in charset: 0x72
               syntax: w    which means: word
             category: .:Base, L:Left-to-right (strong), a:ASCII, l:Latin, r:Roman
          buffer code: #x72
            file code: #x72 (encoded by coding system undecided-unix)
              display: by this font (glyph code)
    nil:-apple-Monaco-medium-normal-normal-*-12-*-*-*-m-0-iso10646-1 (#x55)
Character code properties: customize what to show
  name: LATIN SMALL LETTER R
  general-category: Ll (Letter, Lowercase)
  decomposition: (114) ('r')
There are text properties here:
  face                 org-level-2
  fontified            t
[back]

Solution 3

M-x describe-face

Solution 4

Trey's what face is on the right track. It led me to an email on a mailing list that had this:

(defun what-face (pos)
    (interactive "d")
        (let ((face (or (get-char-property (point) 'read-face-name)
            (get-char-property (point) 'face))))
    (if face (message "Face: %s" face) (message "No face at %d" pos))))

Solution 5

There's a bug in the `what-face' code: the function takes "pos" as an argument but then doesn't use it when getting the face -- instead it uses "(point)", even though the message later claims pos in the "No face at %d" case.

View more solutions

Comments

[Braham Snyder]

In case you're looking for the same functionality using the mouse cursor (if, e.g., you cannot get point on the text in question), see: emacs.stackexchange.com/a/35449/13444

[Trey Jackson]

Duh, forgot it wasn't bundled with Emacs. May I put the source in my answer w/attribution? :)

[viam0Zah]

Which invokes what-cursor-position.

[davidA]

hmmm, sometimes it invokes what-cursor-position, sometimes it displays a list of buffer properties (including font). If I get the former behaviour, moving the cursor and repeating brings on the latter.

[Miserable Variable]

I am so happy I found this, with some unknown combinations of the commands and keystrokes I got emacs to display how I liked it and didn't how to get it back in my next restart

[dolzenko]

This also includes the nice link making it possible to customize the face under cursor immediately

[Adam Spiers]

This would be better placed as a comment on that answer.

[rath]

Even better if it had a fix... +1 for spotting it anyway

[Wilfred Hughes]

This ignores faces set as text properties. If enable hl-line-mode you will only see hl-line as the face, not the other faces. Consider gist.github.com/Wilfred/f7d61b7cdf9fdbb1d11c

[Samuel Edwin Ward]

This works well most of the time, but sometimes for reasons I can't figure out sometimes it doesn't suggest the face I'm looking for. For example in eshell when there is ansi color it just says "default".

[Rory O'Kane]

Karl Fogel pointed out a bug in this code in a separate answer: the output message says it’s describing the face at the pos parameter, but the reading of the face is actually done at (point) rather than at pos.

[Zelphir Kaltstahl]

This shows me a prompt where I can enter something. What would I need to enter, in order to describe the font under cursor?

[Mallory-Erik]

This worked for me to customize code block fonts in org-mode. @Zelphir, the text before the prompt showed the face, in my case at least. You might just hit return. For example my result read Describe face (default ‘org-block-background’): .

[Fernando Basso]

It shows the font name on Emacs GUI. On terminal, Emacs is not responsible for setting the font and therefore such information is not available when one does C-u C-x = in Emacs running on the terminal, like emacs -nw file.txt.

[luochen1990]

This doesn't works, you can use "M-x describe-face" instead.

[cebola]

pos is not a function; in order make the snippet work, you should replace (pos) with pos on lines 3 and 4