examples.txt

#lang racket
(require (planet gcr/pdf-render)
         racket/draw
         slideshow/pict)

;; The first page of a PDF file.
(define page (pdf-page "/tmp/oopsla04-gff.pdf" 0))

(define (save-pict file pict)
  (define bm (pict->bitmap pict))
  (send bm save-file file 'png))

(save-pict "/tmp/rotated.png"
 (rotate
  (frame (scale (inset/clip (page->pict page) -400 -300 -100 -400) 5))
  (* 0.125 pi)))

(save-pict "/tmp/rotated-bitmap.png"
 (rotate
  (frame (scale (inset/clip (bitmap (page->bitmap page))
                            -400 -300 -100 -400)
                5))
  (* 0.125 pi)))


(save-pict "/tmp/search.png"
 (for/fold ([pageview (page->pict page)])
     ([box (in-list (page-find-text page "the"))])
   (match-define (list x1 y1 x2 y2) box)
   (pin-over pageview x1 y1
             (cellophane
              (colorize (filled-rectangle (- x2 x1) (- y2 y1)) "yellow")
              0.5))))

(save-pict "/tmp/text.png"
 ;; Display the outline of characters side-by-side with
 ;; the first page of the original PDF
 (hc-append
  (for/fold ([pageview (frame (apply blank (page-size page)))])
      ([box (in-list (page-text-layout page))])
    (match-define (list x1 y1 x2 y2) box)
    (pin-over pageview x1 y1
              (colorize (rectangle (- x2 x1) (- y2 y1))
                        "gray")))
  (page->pict page)))