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typesetting/quad/quadwriter/render.rkt

171 lines
7.6 KiB
Racket

#lang debug racket/base
(require racket/match
txexpr/base
racket/contract
racket/file
pitfall
quad
hyphenate
sugar/coerce
sugar/debug
"attrs.rkt"
"param.rkt"
"font.rkt"
"layout.rkt"
"log.rkt")
(provide (all-defined-out))
(define default-page-size "letter")
(define default-page-orientation "tall")
(define (setup-pdf-path pdf-path-arg)
(define fallback-path (build-path (find-system-path 'temp-dir) "quadwriter-temp.pdf"))
(path->complete-path (simplify-path (expand-user-path (->path (or pdf-path-arg fallback-path))))))
(define para-break '(q ((break "para"))))
(define line-break '(q ((break "line"))))
(define page-break '(q ((break "page"))))
(define column-break '(q ((break "column"))))
(define (replace-breaks x)
(map-elements (λ (el)
(match el
[(== para-break) q:para-break]
[(== line-break) q:line-break]
[(== column-break) q:column-break]
[(== page-break) q:page-break]
[_ el])) x))
(define (handle-hyphenate qs)
;; find quads that want hyphenation and split them into smaller pieces
;; do this before ->string-quad so that it can handle the sizing promises
(apply append
(for/list ([q (in-list qs)])
(match (quad-ref q :hyphenate)
[#false (list q)]
[_ (for*/list ([str (in-list (quad-elems q))]
[hyphen-char (in-value #\u00AD)]
[hstr (in-value (hyphenate str hyphen-char
#:min-left-length 3
#:min-right-length 3))]
[substr (in-list (regexp-match* (regexp (string hyphen-char)) hstr #:gap-select? #t))])
(struct-copy quad q [elems (list substr)]))]))))
(define (handle-cascading-attrs attrs)
(resolve-font-path attrs)
(resolve-font-size attrs))
(define default-line-height-multiplier 1.42)
(define (setup-qs qx-arg pdf-path)
[define qexpr (replace-breaks qx-arg)]
[define the-quad
(qexpr->quad (list 'q (list->attrs
:font-family default-font-family
:font-size (number->string default-font-size)
:line-height (number->string (floor (* default-line-height-multiplier default-font-size)))) qexpr))]
(setup-font-path-table! pdf-path)
[define atomized-qs
(time-log atomize (atomize the-quad
#:attrs-proc handle-cascading-attrs
#:missing-glyph-action 'fallback
#:fallback "fallback"
#:emoji "emoji"
#:math "math"
#:font-path-resolver resolve-font-path))]
[define hyphenated-qs (time-log hyphenate (handle-hyphenate atomized-qs))]
[define stringified-qs (map ->string-quad hyphenated-qs)]
[define indented-qs (insert-first-line-indents stringified-qs)]
indented-qs)
(define (setup-pdf qs pdf-path compress?)
;; page size can be specified by name, or measurements.
;; explicit measurements from page-height and page-width supersede those from page-size.
(match-define (list page-width page-height) (for/list ([k (list :page-width :page-height)])
(match (quad-ref (car qs) k)
[#false #false]
[val (parse-dimension val 'round)])))
;; `make-pdf` will sort out conflicts among page dimensions
(make-pdf #:compress compress?
#:auto-first-page #false
#:output-path pdf-path
#:width (or (debug-page-width) page-width)
#:height (or (debug-page-height) page-height)
#:size (quad-ref (car qs) :page-size default-page-size)
#:orientation (quad-ref (car qs) :page-orientation default-page-orientation)))
(define (setup-margins qs pdf)
(define default-side-margin (min (* 72 1.5) (floor (* .20 (pdf-width pdf)))))
(define default-top-margin (min 72 (floor (* .10 (pdf-height pdf)))))
;; if only left or right margin is provided, copy other value in preference to default margin
(define left
(or (debug-x-margin)
(quad-ref (car qs) :page-margin-left
(λ () (quad-ref (car qs) :page-margin-right default-side-margin)))))
(define right
(or (debug-x-margin)
(quad-ref (car qs) :page-margin-right
(λ () (quad-ref (car qs) :page-margin-left default-side-margin)))))
(define top
(or (debug-y-margin)
(quad-ref (car qs) :page-margin-top
(λ () (quad-ref (car qs) :page-margin-bottom default-top-margin)))))
(define vert-optical-adjustment 10)
(define bottom
(or (debug-y-margin)
(quad-ref (car qs) :page-margin-bottom
(λ () (+ vert-optical-adjustment (quad-ref (car qs) :page-margin-top (* default-top-margin 1.4)))))))
(list left top right bottom))
(define default-column-count 1)
(define (setup-column-count qs)
(define cc (or (debug-column-count) (quad-ref (car qs) :column-count default-column-count)))
(unless (exact-nonnegative-integer? cc)
(raise-argument-error 'render-pdf "positive integer" cc))
cc)
(define default-column-gap 36)
(define (setup-column-gap qs)
(or (debug-column-gap) (quad-ref (car qs) :column-gap default-column-gap)))
(define/contract (render-pdf qx-arg pdf-path-arg
#:replace [replace? #t]
#:compress [compress? #t])
((qexpr? (or/c #false path? path-string?)) (#:replace any/c
#:compress any/c) . ->* . (or/c void? bytes?))
(define pdf-path (setup-pdf-path pdf-path-arg))
(when (and (not replace?) (file-exists? pdf-path))
(raise-argument-error 'render-pdf "path that doesn't exist" pdf-path))
(define qs (setup-qs qx-arg pdf-path))
(parameterize ([current-pdf (setup-pdf qs pdf-path compress?)]
[verbose-quad-printing? #false])
(match-define (list left-margin top-margin right-margin bottom-margin) (setup-margins qs (current-pdf)))
(define printable-width (- (pdf-width (current-pdf)) left-margin right-margin))
(define printable-height (- (pdf-height (current-pdf)) top-margin bottom-margin))
(define column-count (setup-column-count qs))
(define column-gap (setup-column-gap qs))
(define line-wrap-size (/ (- printable-width (* (sub1 column-count) column-gap)) column-count))
(define line-qs (time-log line-wrap (apply-keeps (line-wrap qs line-wrap-size))))
(define col-quad-prototype (struct-copy quad q:column
[size (pt line-wrap-size printable-height)]))
(define column-qs (time-log column-wrap (column-wrap line-qs printable-height column-gap col-quad-prototype)))
(define page-quad-prototype (struct-copy quad q:page
[shift (pt left-margin top-margin)]
[size (pt line-wrap-size printable-height)]))
(define page-qs (time-log page-wrap (page-wrap column-qs printable-width page-quad-prototype)))
(define positioned-qs (time-log position (position (struct-copy quad q:doc [elems page-qs]))))
(time-log draw (draw positioned-qs (current-pdf))))
(if pdf-path-arg
(log-quadwriter-info (format "wrote PDF to ~a" pdf-path))
(begin0
(file->bytes pdf-path)
(delete-file pdf-path))))