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215 lines
6.4 KiB
Racket
215 lines
6.4 KiB
Racket
#lang racket/base
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(require racket/class racket/draw br/list racket/list racket/format racket/port)
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(require sugar/debug)
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(provide PDFDocument)
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(require "reference.rkt" "struct.rkt" "object.rkt" "page.rkt")
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(define PDFDocument
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(class object% ; actually is an instance of readable.Stream, which is an input port
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(init-field [options (hasheq)])
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(let ([output-file (hash-ref options 'out "outrkt.pdf")])
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(super-new))
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; list of byte chunks to push onto
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; simulates interface of stream.readable
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(field [byte-strings empty])
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;; PDF version
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(field [version 1.3])
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;; Whether streams should be compressed
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(field [compress (hash-ref options 'compress #t)])
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(field [_pageBuffer null])
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(field [_pageBufferStart 0])
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;; The PDF object store
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(field [_offsets null])
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(field [_waiting 0])
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(field [_ended #f])
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(field [_offset 0])
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(field [_root (ref
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(hasheq 'Type "Catalog"
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'Pages (ref
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(hasheq 'Type "Pages"
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'Count 0
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'Kids empty))))])
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;; The current page
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(field [page #f])
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;; todo
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;; Initialize mixins
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#;(initColor)
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#;(initVector)
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#;(initFonts)
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#;(initText)
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#;(initImages)
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;; Initialize the metadata
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(field [info (hasheq
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'Producer "PitfallKit"
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'Creator "PitfallKit"
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'CreationDate (seconds->date (current-seconds)))])
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(when (hash-ref options 'info #f)
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(for ([(key val) (in-hash (hash-ref options 'info))])
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(hash-set! info key val)))
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(report info)
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;; Write the header
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;; PDF version
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(_write (format "%PDF-~a" version))
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;; 4 binary chars, as recommended by the spec
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(let ([c (integer->char #xFF)])
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(_write (string-append "%" (string c c c c))))
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;; Add the first page
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(unless (not (hash-ref options 'autoFirstPage #t))
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(addPage))
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;; todo
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;;mixin = (methods) =>
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;;for name, method of methods
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;;this::[name] = method
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;; todo
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;; Load mixins
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;mixin require './mixins/color'
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;mixin require './mixins/vector'
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;mixin require './mixins/fonts'
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;mixin require './mixins/text'
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;mixin require './mixins/images'
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;mixin require './mixins/annotations'
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(field [x 0])
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(field [y 0])
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(field [_ctm null])
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(define/public (addPage [my-options options])
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;; end the current page if needed
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(unless (hash-ref options 'bufferPages #f)
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(flushPages))
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;; create a page object
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(define page (make-object PDFPage this my-options))
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(push! _pageBuffer page)
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#|
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;; add the page to the object store
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(define pages (make-hasheq)) ; todo @_root.data.Pages.data
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(hash-update! pages 'Kids (λ (val) (cons 42 val)) null) ; todo @page.dictionary
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(hash-update! pages 'Count add1 0)
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;; reset x and y coordinates
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(set! x 42) ;; todo @page.margins.left
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(set! y 42) ;; todo @page.margins.top
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;; flip PDF coordinate system so that the origin is in
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;; the top left rather than the bottom left
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(set! _ctm '(1 0 0 1 0 0))
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;; (transform 1 0 0 -1 0 @page.height) ;; todo
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;; @emit('pageAdded') ;; todo
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this
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|#
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)
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(define/public (flushPages)
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;; this local variable exists so we're future-proof against
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;; reentrant calls to flushPages.
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(define pages _pageBuffer)
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(set! _pageBuffer empty)
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(set! _pageBufferStart (+ _pageBufferStart (length pages)))
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(for ([page (in-list pages)])
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(send page end)))
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;; every js function argument is 'undefined' by default
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;; so even a function defined without default values
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;; can be called without arguments
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(define/public (ref [data (make-hasheq)])
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(define ref (make-object PDFReference this (add1 (length _offsets)) data))
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(push! _offsets #f) ; placeholder for this object's offset once it is finalized
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(set! _waiting (add1 _waiting))
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ref)
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(define/public (push chunk)
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(push! byte-strings chunk))
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(define/public (_write data)
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(let ([data (if (not (bytes? data))
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; `string->bytes/latin-1` is equivalent to plain binary encoding
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(string->bytes/latin-1 (string-append data "\n"))
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data)])
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(push data)
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(report byte-strings)
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(set! _offset (+ _offset (bytes-length data)))))
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(field [op #f])
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(define/public (pipe port)
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(set! op port))
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(define _info #f)
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(define/public (end)
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(flushPages)
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(set! _info (ref))
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(for ([(key val) (in-hash info)])
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;; upgrade string literal to String struct
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(hash-set! (get-field data _info) key
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(if (string? val) (String val) val)))
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(send _info end)
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;; todo: fonts
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;; for name, font of @_fontFamilies
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;; font.finalize()
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(send _root end)
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(send (hash-ref (get-field data _root) 'Pages) end)
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(if (or (zero? _waiting) 'debug)
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(_finalize)
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(set! _ended #t))
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'done)
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(define/public (_finalize [fn #f])
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;; generate xref
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(define xRefOffset _offset)
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(_write "xref")
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(_write (format "0 ~a" (add1 (length _offsets))))
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(_write "0000000000 65535 f ")
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(for ([offset (in-list _offsets)])
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(_write (string-append
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(~r (or offset (random 17)) #;debug #:min-width 10 #:pad-string "0")
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" 00000 n ")))
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;; trailer
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(_write "trailer")
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;; todo: make `PDFObject:convert` a static method
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(_write (send (make-object PDFObject) convert
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(hasheq 'Size (add1 (length _offsets))
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'Root _root
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'Info _info)))
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(_write "startxref")
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(_write (number->string xRefOffset))
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(_write "%%EOF")
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;; end the stream
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;; in node you (push null) which signals to the stream
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;; to copy to its output port
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;; here we'll do it manually
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(copy-port (open-input-bytes
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(apply bytes-append (reverse byte-strings)))
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op)
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(close-output-port op))))
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(define doc (new PDFDocument))
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(module+ test
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(require rackunit)
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(send doc pipe (open-output-file "testrkt0.pdf" #:exists 'replace))
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(check-equal? (send doc end) 'done)) |