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typesetting/pitfall/pitfall/images.rkt

121 lines
4.2 KiB
Racket

#lang racket/base
(require
racket/class
racket/match
sugar/unstable/dict
"core.rkt"
"page.rkt"
"png.rkt"
"jpeg.rkt")
(provide image-mixin)
(define (open-pdf-image src label)
(define data (cond
[(bytes? src) (open-input-bytes src)]
[(regexp-match #rx"^data:.+;base64,(.*)$" src) (void)] ;; base64 ; todo
[else (open-input-file src)]))
(define img-constructor
(cond
[(equal? (peek-bytes 2 0 data) (bytes #xff #xd8)) make-jpeg]
[(equal? (peek-bytes 4 0 data) (apply bytes (map char->integer '(#\u0089 #\P #\N #\G)))) make-png]
[else (raise-argument-error 'open-pdf-image "valid image format" src)]))
(img-constructor data label))
(define (image-mixin [% object%])
(class %
(super-new)
(field [@image-registry (mhash)]
[@image-count 0])
(inherit-field [@x x] [@y y])
(inherit page)
(define/public (image src [x-in #f] [y-in #f] [options (mhasheq)])
(define x (or x-in (hash-ref options 'x #f) @x))
(define y (or y-in (hash-ref options 'y #f) @y))
(define image (cond
[(and (string? src) (hash-ref @image-registry src #f))]
[(and ($img? src) ($img-width src) ($img-height src)) src]
[else (send this open-image src)]))
(unless ($img-ref image) (($img-embed-proc image) image))
(hash-ref! (page-xobjects (page)) ($img-label image) ($img-ref image))
(define image-width ($img-width image))
(define image-height ($img-height image))
(define options-width (hash-ref options 'width #f))
(define options-height (hash-ref options 'height #f))
(define w (or options-width image-width))
(define h (or options-height image-height))
(define wp #f)
(define hp #f)
(define bp #f)
(define ip #f)
(define bw #f)
(define bh #f)
(cond
[(and options-width (not options-height))
(set! wp (/ w image-width))
(set! w (* image-width wp))
(set! h (* image-height wp))]
[(and options-height (not options-width))
(set! hp (/ h image-width))
(set! w (* image-width hp))
(set! h (* image-height hp))]
[(hash-ref options 'scale #f)
=> (λ (scale-val)
(set! w (* image-width scale-val))
(set! h (* image-height scale-val)))]
[(hash-ref options 'fit #f)
=> (λ (fit-val)
(match-define (list bw bh) fit-val)
(set! bp (/ bw bh))
(set! ip (/ image-width image-height))
(cond
[(> ip bp)
(set! w bw)
(set! h (/ bw ip))]
[else
(set! w (* bh ip))
(set! h bh)]))]
[(hash-ref options 'cover #f)
=> (λ (cover-val)
(match-define (list bw bh) cover-val)
(set! bp (/ bw bh))
(set! ip (/ image-width image-height))
(cond
[(> ip bp)
(set! w (* bh ip))
(set! h bh)]
[else
(set! w bw)
(set! h (/ bw ip))]))])
(when (or (hash-ref options 'fit #f) (hash-ref options 'cover #f))
(case (hash-ref options 'align #f)
[("center") (set! x (+ x (/ bw 2) (- (/ w 2))))]
[("right") (set! x (+ x bw - w))])
(case (hash-ref options 'valign #f)
[("center") (set! y (+ y (/ bh 2) (- (/ h 2))))]
[("bottom") (set! y (+ y bh - h))]))
;; Set the current y position to below the image if it is in the document flow
(when (= @y y) (set! y (+ y h)))
(send this save)
(send this transform w 0 0 (- h) x (+ y h))
(send this add-content (format "/~a Do" ($img-label image)))
(send this restore)
this)
(define/public (open-image src)
(cond
[(and (string? src) (hash-ref @image-registry src #f))]
[else
(set! @image-count (add1 @image-count))
(define image-id (string->symbol (format "I~a" @image-count)))
(define new-image (open-pdf-image src image-id))
(when (string? src) (hash-set! @image-registry src new-image))
new-image]))))