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typesetting/quad/quadwriter/render.rkt

287 lines
12 KiB
Racket

#lang debug racket/base
(require (for-syntax racket/base racket/syntax)
racket/match
txexpr/base
racket/contract
racket/file
racket/string
racket/sequence
racket/list
pitfall
quad
hyphenate
pollen/unstable/typography
pollen/decode
sugar/coerce
sugar/debug
sugar/list
"attrs.rkt"
"param.rkt"
"font.rkt"
"layout.rkt"
"log.rkt")
(provide (all-defined-out))
(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-syntax (define-break-types stx)
(syntax-case stx ()
[(_ ALL-BREAKS-ID . TYPES)
(with-syntax ([((TYPE-BREAK TYPE-STR Q:TYPE-BREAK) ...)
(for/list ([type (in-list (syntax->list #'TYPES))])
(list
(format-id #'TYPES "~a-break" type)
(symbol->string (syntax->datum type))
(format-id #'TYPES "q:~a-break" type)))])
#'(begin
(define TYPE-BREAK '(q ((break TYPE-STR)))) ...
(define ALL-BREAKS-ID (list (cons TYPE-BREAK Q:TYPE-BREAK) ...))))]))
(define-break-types all-breaks para line page column hr section)
(define (replace-breaks x)
(map-elements (λ (el)
(cond
[(assoc el all-breaks) => cdr]
[else 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)
[#true #:when (and (pair? (quad-elems q))
(andmap string? (quad-elems 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)]))]
[_ (list q)]))))
(define (string->feature-list str)
(for/list ([kv (in-slice 2 (string-split str))])
(cons (string->bytes/utf-8 (first kv)) (string->number (second kv)))))
(define (parse-font-features! attrs)
(cond
[(match (hash-ref attrs :font-features-adjust #f)
[(? string? str)
;; override any existing features
(define parsed-features (string->feature-list str))
(hash-update! attrs :font-features (λ (fs) (remove-duplicates (append parsed-features fs) equal? #:key car)))
;; adjustment is incorporated, so delete it
(hash-set! attrs :font-features-adjust #false)]
[_ #false])]
[else (match (hash-ref attrs :font-features #f)
[(? string? str)
(define parsed-features (string->feature-list str))
(hash-set! attrs :font-features parsed-features)]
[_ #false])]))
(define (parse-dimension-strings! attrs)
(for ([k (in-hash-keys attrs)]
#:when (takes-dimension-string? k))
(hash-update! attrs k parse-dimension))
attrs)
(define (complete-every-path! attrs)
;; relies on `current-directory` being parameterized to source file's dir
(for ([k (in-hash-keys attrs)]
#:when (takes-path? k))
(hash-update! attrs k (compose1 path->string path->complete-path)))
attrs)
(define (handle-cascading-attrs attrs)
(parse-dimension-strings! attrs)
(complete-every-path! attrs)
(resolve-font-path! attrs)
(resolve-font-size! attrs)
(parse-font-features! attrs))
(define default-line-height-multiplier 1.42)
(define (setup-qs qx-arg pdf-path)
(define qexpr (decode qx-arg
#:string-proc (λ (str) (smart-ellipses (smart-dashes str)))
#:txexpr-proc smart-quotes))
(define super-qexpr (replace-breaks qexpr))
(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)))) super-qexpr)))
(setup-font-path-table! pdf-path)
(define atomized-qs (atomize the-quad
#:attrs-proc handle-cascading-attrs
#:missing-glyph-action 'fallback
#:fallback "fallback"
#:emoji "fallback-emoji"
#:math "fallback-math"
#:font-path-resolver resolve-font-path!))
(define hyphenated-qs (time-log hyphenate (handle-hyphenate atomized-qs)))
(define typed-quads (map generic->typed-quad hyphenated-qs))
(define indented-qs (insert-first-line-indents typed-quads))
indented-qs)
(define (setup-margins qs page-width page-height)
;; if only left or right margin is provided, copy other value in preference to default margin
(define q (car qs))
(define default-side-margin (min (* 72 1.5) (floor (* .20 page-width))))
(define default-top-margin (min 72 (floor (* .10 page-height))))
(define left (cond
[(debug-x-margin)]
[(quad-ref q :page-margin-left)]
[(quad-ref q :page-margin-right)]
[else default-side-margin]))
(define right (cond
[(debug-x-margin)]
[(quad-ref q :page-margin-right)]
[(quad-ref q :page-margin-left)]
[else default-side-margin]))
(define top (cond
[(debug-y-margin)]
[(quad-ref q :page-margin-top)]
[(quad-ref q :page-margin-bottom)]
[else default-top-margin]))
(define bottom (cond
[(debug-y-margin)]
[(quad-ref q :page-margin-bottom)]
[else
(define vert-optical-adjustment 10)
(+ vert-optical-adjustment
(cond
[(quad-ref q :page-margin-top)]
[else (* 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
[base-dir-arg #false]
#:replace [replace-existing-file? #t]
#:compress [compress? #t])
((qexpr? (or/c #false path? path-string?))
((or/c #false path? path-string?)
#:replace any/c
#:compress any/c) . ->* . (or/c void? bytes?))
(define base-dir (match base-dir-arg
[#false (current-directory)]
[path (define-values (dir name _) (split-path path))
dir]))
(define pdf-path (setup-pdf-path pdf-path-arg))
(unless replace-existing-file?
(when (file-exists? pdf-path)
(raise-argument-error 'render-pdf "path that doesn't exist" pdf-path)))
(define the-pdf (make-pdf #:compress compress?
#:auto-first-page #false
#:output-path pdf-path))
(parameterize ([current-pdf the-pdf]
;; set `current-directory` so that ops like `path->complete-path`
;; will be handled relative to the original directory
[current-directory base-dir]
[section-pages-used 0]
[verbose-quad-printing? #false])
(define qs (time-log setup-qs (setup-qs qx-arg pdf-path)))
(define sections
(for/fold ([sections-acc null]
#:result (reverse sections-acc))
([qs (in-list (filter-split qs section-break-quad?))])
(match-define (list page-width page-height) (parse-page-size (and (pair? qs) (car qs))))
(match-define (list left-margin top-margin right-margin bottom-margin)
(setup-margins qs page-width page-height))
(define gutter-margin (and (pair? qs) (quad-ref (car qs) :page-margin-gutter 0)))
(define printable-width (- page-width left-margin right-margin gutter-margin))
(define printable-height (- page-height 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
(λ (page-count)
(define left-shift (+ left-margin (if (odd? page-count) gutter-margin 0)))
(struct-copy quad q:page
[shift (pt left-shift top-margin)]
[size (pt line-wrap-size printable-height)])))
(define section-starting-side (string->symbol (quad-ref (car qs) :page-side-start "right")))
(define insert-blank-page?
(and (pair? qs)
;; if we need a 'left page and will get 'right (or vice versa) then insert page
(let ([next-page-side (if (even? (add1 (section-pages-used))) 'left 'right)])
(not (eq? section-starting-side next-page-side)))))
;; update page count before starting page wrap
(when insert-blank-page?
(section-pages-used (add1 (section-pages-used))))
(define section-pages (time-log page-wrap (page-wrap column-qs printable-width page-quad-prototype)))
(begin0
(cond
[insert-blank-page?
(match section-starting-side
['left
;; blank page goes at beginning of current section
(define page-from-current-section (car section-pages))
(define blank-page (struct-copy quad page-from-current-section [elems null]))
(define new-section (struct-copy quad q:section [elems (cons blank-page section-pages)]))
(cons new-section sections-acc)]
[_ ;; must be 'right
;; blank page goes at end of previous section (if it exists)
(define new-section (struct-copy quad q:section [elems section-pages]))
(match sections-acc
[(cons previous-section other-sections)
(define previous-section-pages (quad-elems previous-section))
(define page-from-previous-section (car previous-section-pages))
(define blank-page (struct-copy quad page-from-previous-section [elems null]))
(define revised-previous-section
(struct-copy quad previous-section
[elems (append previous-section-pages (list blank-page))]))
(list* new-section revised-previous-section other-sections)]
[_ (list new-section)])])]
[else (define new-section (struct-copy quad q:section [elems section-pages]) )
(cons new-section sections-acc)])
(section-pages-used (+ (section-pages-used) (length section-pages))))))
(define doc (time-log position (position (struct-copy quad q:doc [elems sections]))))
(time-log draw (draw doc (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))))