;; this example reads a black-and-white scanned document and extracts the 
;; components which are roughly letter-sized

(require-extension format)
(require-extension leptonica)
(require-extension srfi-42)

(define original-pix (pix-read "feyn.tif"))
(format #t "Size of original ~d x ~d, colour depth ~d bpp~&"
        (pix-get-width original-pix)
        (pix-get-height original-pix)
        (pix-get-depth original-pix))

(format #t "Image contains ~d components (by 8) and ~d (by 4)~&"
        (pix-count-conn-comp original-pix 8)
        (pix-count-conn-comp original-pix 4))

(format #t "Analysing by 8-wise connectivity~&")

(let-values 
  (((boxes images) (pix-conn-comp-pixa original-pix 8)))
  (when (eq? #f boxes) (error "Failure in identifying components"))

  (format #t "There are ~d boxes~&"
          (boxa-get-count boxes))

  (do-ec (: i (boxa-get-count boxes))
         (let ((box (boxa-get-box boxes i L-COPY)))
           (let-values 
             (((x y w h) (box-get-geometry box)))
             ; constraint the size of image to save
             (when (and (> w 10) (< w 50)
                        (> h 10) (< h 50))
               (format #t "Box ~d at (~d, ~d) size ~d x ~d~&"
                       i x y w h)
               (let ((pix (pixa-get-pix images i L-COPY)))
                 (pix-write (string-concatenate (list "feyn-" (number->string i) ".png"))
                            pix 
                            IFF-PNG)))))))