Variable: face-font-selection-order
face-font-selection-order is a customizable variable defined in
faces.el.gz.
Value
(:width :height :weight :slant)
Documentation
A list specifying how face font selection chooses fonts.
Each of the four symbols :width, :height, :weight, and :slant must appear once in the list, and the list must not contain any other elements. Font selection first tries to find a best matching font for those face attributes that appear before in the list. For example, if :slant appears before :height, font selection first tries to find a font with a suitable slant, even if this results in a font height that isn't optimal.
Probably introduced at or before Emacs version 21.1.
Source Code
;; Defined in /usr/src/emacs/lisp/faces.el.gz
(defcustom face-font-selection-order
'(:width :height :weight :slant)
"A list specifying how face font selection chooses fonts.
Each of the four symbols `:width', `:height', `:weight', and `:slant'
must appear once in the list, and the list must not contain any other
elements. Font selection first tries to find a best matching font
for those face attributes that appear before in the list. For
example, if `:slant' appears before `:height', font selection first
tries to find a font with a suitable slant, even if this results in
a font height that isn't optimal."
:tag "Font selection order"
:type '(list symbol symbol symbol symbol)
:group 'font-selection
:set (lambda (symbol value)
(set-default symbol value)
(internal-set-font-selection-order value)))