Re: Changing font weight with buffer-face-mode-invoke

[Heime <heimeborgia@protonmail.com>]

On Wednesday, June 26th, 2024 at 6:39 PM, Eli Zaretskii <eliz@gnu.org> wrote:

> > Date: Wed, 26 Jun 2024 17:08:40 +0000
> > From: Heime heimeborgia@protonmail.com
> > Cc: help-gnu-emacs@gnu.org
> > 
> > > Use standard weights: regular, medium, bold. Some font families have
> > > also additional weights: light, semi-light, semi-bold, extra-bold.
> > > The full list of weight values is in the ELisp manual, in the node
> > > "Face Attributes".
> > 
> > Some faces, e.g. "URW Chancery L" have "Medium Italic" and "Bold Italic".
> > And not all faces have the weights declared in the list. Could there be
> > an elisp function that returns a list of the available weights and styles
> > for each entry in the list of font families ?
> 
> 
> I think you want list-fonts. See the node "Low-Level Font" in the
> ELisp manual, it describes this stuff.

Have done the following tools.  But am getting

Debugger entered--Lisp error: (wrong-type-argument stringp #<font-entity ftcrhb urw URW\ Chancery\ L nil iso10646-1 medium italic normal 0 nil nil 0 ((:font-entity "/usr/share/fonts/X11/Type1/z003034l.pfb" . 0))>)
  string-match("-" #<font-entity ftcrhb urw URW\ Chancery\ L nil iso10646-1 medium italic normal 0 nil nil 0 ((:font-entity "/usr/share/fonts/X11/Type1/z003034l.pfb" . 0))> 0)
  split-string(#<f

(defun mon-font-info (font)

  "Get font attributes for FONT."

  (let ((attrs (split-string font "-")))

    (vector (nth 1 attrs)     ; Weight

            (nth 2 attrs)     ; Slant

            (nth 3 attrs))))  ; Width

(defun mon-list-font-family (font-family)

  "List all fonts for the specified FONT-FAMILY."

  (interactive

    (list

      (completing-read "Family: " (font-family-list) nil t)))

  (let ( (font-spec (font-spec :family font-family))

         (fonts (list-fonts (font-spec :family font-family))) )

    (if fonts

        (progn

          (switch-to-buffer "*Font List*")

          (erase-buffer)

          (insert (format "Fonts for family: %s\n\n" font-family))

          (dolist (font fonts)

            (let* ( (font-info (mon-font-info font))

                    (weight (aref font-info 1))

                    (slant  (aref font-info 2))

                    (width  (aref font-info 3)) )

              (insert (format

                "Weight: %-10s Slant: %-10s Width: %-10s Full: %s\n"

                weight slant width font))))

          (goto-char (point-min)))

      (message "No fonts found for family: %s" font-family))))