如何在Scheme中将十进制转换为十六进制？ （需要将GIMP中的RGB转换为十六进制）

Question

如何在Scheme中将十进制转换为十六进制？

在以下情况下，需要在GIMP中将JSON中的RGB转换为HEX：

(set! imgcolor (car (gimp-color-picker image newDraw 1 1 TRUE TRUE 1)))

在Script-fu中。现在的结果是RGB之类的（255 255 255）

Answer 1

在Palale-export.scm中找到答案，由Barak Itkin撰写

; For all the operations below, this is the order of respectable digits:
(define conversion-digits (list "0" "1" "2" "3" "4" "5" "6" "7" "8" "9"
                                "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k"
                "l" "m" "n" "o" "p" "q" "r" "s" "t" "u" "v"
                "w" "x" "y" "z"))


; Converts a decimal number to another base. The returned number is a string
(define (convert-decimal-to-base num base)
  (if (< num base) 
    (list-ref conversion-digits num) 
    (let loop ((val num)
               (order (inexact->exact (truncate (/ (log num) 
                                                   (log base)))))
               (result ""))
      (let* ((power (expt base order))
             (digit (quotient val power)))
        (if (zero? order)
          (string-append result (list-ref conversion-digits digit)) 
          (loop (- val (* digit power))
                (pred order)
                (string-append result (list-ref conversion-digits digit))))))))


; Convert a color to a hexadecimal string
; '(255 255 255) => "#ffffff"
(define (color-rgb-to-hexa-decimal color)
  (string-append "#"
                 (pre-pad-number
          (convert-decimal-to-base (car color) 16) 2 "0")
                 (pre-pad-number
          (convert-decimal-to-base (cadr color) 16) 2 "0")
                 (pre-pad-number
          (convert-decimal-to-base (caddr color) 16) 2 "0")
                 )
  )

; Присваеваем HEX переменной 
(set! imgcolorHEX (color-rgb-to-hexa-decimal imgcolor))