Add an example with a bytefield diagram

[Guillaume Grossetie]

yuzutech/kroki#162

(defattrs :bg-green {:fill "#a0ffa0"})
(defattrs :bg-yellow {:fill "#ffffa0"})
(defattrs :bg-pink {:fill "#ffb0a0"})
(defattrs :bg-cyan {:fill "#a0fafa"})
(defattrs :bg-purple {:fill "#e4b5f7"})

(defn draw-group-label-header
  [span label]
  (draw-box (text label [:math {:font-size 12}]) {:span    span
                                                  :borders #{}
                                                  :height  14}))

(defn draw-remotedb-header
  [kind args]
  (draw-column-headers)
  (draw-group-label-header 5 "start")
  (draw-group-label-header 5 "TxID")
  (draw-group-label-header 3 "type")
  (draw-group-label-header 2 "args")
  (draw-group-label-header 1 "tags")
  (next-row 18)

  (draw-box 0x11 :bg-green)
  (draw-box 0x872349ae [{:span 4} :bg-green])
  (draw-box 0x11 :bg-yellow)
  (draw-box (text "TxID" :math) [{:span 4} :bg-yellow])
  (draw-box 0x10 :bg-pink)
  (draw-box (hex-text kind 4 :bold) [{:span 2} :bg-pink])
  (draw-box 0x0f :bg-cyan)
  (draw-box (hex-text args 2 :bold) :bg-cyan)
  (draw-box 0x14 :bg-purple)

  (draw-box (text "0000000c" :hex [[:plain {:font-weight "light" :font-size 16}] " (12)"])
            [{:span 4} :bg-purple])
  (draw-box (hex-text 6 2 :bold) [:box-first :bg-purple])
  (doseq [val [6 6 3 6 6 6 6 3]]
    (draw-box (hex-text val 2 :bold) [:box-related :bg-purple]))
  (doseq [val [0 0]]
    (draw-box val [:box-related :bg-purple]))
  (draw-box 0 [:box-last :bg-purple]))

;; Figure 48: Cue point response message.

(draw-remotedb-header 0x4702 9)

(draw-box 0x11)
(draw-box 0x2104 {:span 4})
(draw-box 0x11)
(draw-box 0 {:span 4})
(draw-box 0x11)
(draw-box (text "length" [:math] [:sub 1]) {:span 4})
(draw-box 0x14)

(draw-box (text "length" [:math] [:sub 1]) {:span 4})
(draw-gap "Cue and loop point bytes")

(draw-box nil :box-below)
(draw-box 0x11)
(draw-box 0x36 {:span 4})
(draw-box 0x11)
(draw-box (text "num" [:math] [:sub "hot"]) {:span 4})
(draw-box 0x11)
(draw-box (text "num" [:math] [:sub "cue"]) {:span 4})

(draw-box 0x11)
(draw-box (text "length" [:math] [:sub 2]) {:span 4})
(draw-box 0x14)
(draw-box (text "length" [:math] [:sub 2]) {:span 4})
(draw-gap "Unknown bytes" {:min-label-columns 6})
(draw-bottom)