SVG Rounded box for Emacs

rounded-box.el

(require 'svg)

;; Rounded boxes using SVG:  
;; This could be made into a function but size of text needs to be computed

(defun tag (text &optional foreground background font-size)
  (let* ((font-size   (or font-size 12))
         ;; The char-width ratio depends on the font family
         (char-width  (* font-size 0.58))
         (char-height (+ font-size 1))
         (hmargin char-width)
         (vmargin (* font-size 0.175))
         (radius  (/ font-size 4))
         (background (or background "blue"))
         (foreground (or foreground "white"))
         (width  (+ (* char-width (length text)) (* hmargin 2)))
         (height (+ char-height (* vmargin 2)))
         (svg (svg-create width height)))
  (svg-rectangle svg 0 0 width height :fill background :rx radius)
  (svg-text svg text
            :font-family "Roboto Mono" :font-weight "light"
            :font-size font-size :fill foreground
            :x hmargin :y char-height)
  (insert-image (svg-image svg :ascent 'center)))
)

(tag "IMPORTANT" "white" "blue"   12)
(tag "WARNING"   "white" "orange" 12)
(tag "DANGER"    "white" "red"    24)

;; Important:  
;; Warning:    
;; Danger: