make-captcha

(define (make-captcha text filename width height)
  (let* ((img         (car (gimp-image-new width height RGB)))
         (bg          (car (gimp-layer-new img width height RGBA-IMAGE "bg" 100 NORMAL-MODE)))
         (noise-layer (car (gimp-layer-new img width height RGBA-IMAGE "noise" 100 NORMAL-MODE)))
         (text-layer  (car (gimp-text-fontname img -1 30 50 text 0 TRUE 60 PIXELS "FreeMono Bold"))))
    
    (gimp-display-new img)

    (gimp-image-add-layer img bg 0)
    (gimp-image-lower-layer-to-bottom img bg)
    (gimp-drawable-fill bg 2)
    
    (gimp-image-add-layer img noise-layer -1)    
    (gimp-drawable-set-visible noise-layer FALSE)
    (plug-in-solid-noise TRUE img noise-layer FALSE TRUE (random 120) 1 1.5 1.5)
    
    (let ((bottom (car (gimp-image-merge-visible-layers img 1))))
      (plug-in-displace TRUE img bottom
                        50 50 TRUE TRUE noise-layer noise-layer 1)
      (plug-in-autocrop FALSE img bottom))
    
    (gimp-image-flatten img)
    (file-png-save-defaults FALSE img img filename filename)
    (gimp-image-delete img)))