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typesetting/pitfall/pitfall/annotation.rkt

67 lines
1.9 KiB
Racket

#lang racket/base
(require
"core.rkt"
"reference.rkt"
"page.rkt"
"color.rkt"
racket/match
sugar/unstable/dict)
(provide (all-defined-out))
(define annots-cache (make-hash))
(define link-ref-cache (make-hash))
(define (reset-annotations-cache!)
(set! link-ref-cache (make-hash))
(set! annots-cache (make-hash)))
(define (annotate doc x y w h options)
(hash-set*! options
'Type 'Annot
'Rect (convert-rect doc x y w h)
'Border '(0 0 0))
(unless (eq? (hash-ref options 'Subtype #f) 'Link)
(hash-ref! options 'C
(λ ()
(normalize-color (or (hash-ref options 'color #f) '(0 0 0))))))
(hash-remove! options 'color)
(for ([(k v) (in-hash options)])
(hash-set! options (string->symbol (string-titlecase (symbol->string k))) v))
;; reuse previous identical annotations (= fewer refs in file)
(define annots-ref
(hash-ref! annots-cache (sort (hash->list options) #:key car symbol<?)
(λ ()
(define new-ref (make-ref options))
(ref-end new-ref)
new-ref)))
(page-annotations (current-page doc) annots-ref)
doc)
(define (convert-rect doc x1 y1 w h)
;; flip y1 and y2
(let ([y2 y1]
[y1 (+ y1 h)]
[x2 (+ x1 w)])
(match-define (list m0 m1 m2 m3 m4 m5) (pdf-ctm doc))
(let* ([x1 (+ (* x1 m0) (* y1 m2) m4)]
[y1 (+ (* x1 m1) (* y1 m3) m5)]
[x2 (+ (* x2 m0) (* y2 m2) m4)]
[y2 (+ (* x2 m1) (* y2 m3) m5)])
(list x1 y1 x2 y2))))
(define (link doc x y w h url [options (mhasheq)])
;; reuse previous links (= fewer refs in file)
(define link-ref
(hash-ref! link-ref-cache url
(λ ()
(define link-ref (make-ref (mhasheq 'S 'URI 'URI url)))
(ref-end link-ref)
link-ref)))
(hash-set*! options
'Subtype 'Link
'A link-ref)
(annotate doc x y w h options))