#lang debug racket/base (require racket/match racket/contract racket/file racket/string racket/sequence racket/list racket/dict pitfall quad hyphenate pollen/decode sugar/coerce sugar/list "attrs.rkt" "param.rkt" "font.rkt" "layout.rkt" "log.rkt") (provide (all-defined-out)) (define (setup-pdf-path pdf-path-arg) ;; convert pathlike arg into nice complete path. (path->complete-path (simplify-path (expand-user-path (->path (match pdf-path-arg ;; a #false arg signals that we're going to return the bytes directly, ;; so we use a temp path to write the file, and we'll delete it later. [#false (build-path (find-system-path 'temp-dir) "quadwriter-temp.pdf")] [path path])))))) (define (handle-hyphenate q) ;; find quads that want hyphenation and split them into smaller pieces ;; do this before ->string-quad so that it can handle the sizing promises (cond [(and (quad-ref q :hyphenate) (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))]) (quad-copy q [elems (list substr)]))] [else (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) ;; `font-features` are OpenType font feature specifiers. (match (hash-ref attrs :font-features-adjust #false) [(? string? str) ;; adjustment: parse the feature string and append to the current feature set (define parsed-features (string->feature-list str)) (hash-update! attrs :font-features (λ (fs) (remove-duplicates (append parsed-features fs) equal? #:key car))) ;; once adjustment is incorporated, delete it (hash-set! attrs :font-features-adjust #false)] [_ (match (hash-ref attrs :font-features #false) ;; override: parse features & replace current set [(? string? str) (define parsed-features (string->feature-list str)) (hash-set! attrs :font-features parsed-features)] [_ (void)])])) (define (parse-dimension-strings! attrs) ;; certain attributes can be "dimension strings", which are strings like "3in" or "4.2cm" ;; we parse them into the equivalent measurement in points. (for ([k (in-hash-keys attrs)] #:when (takes-dimension-string? k)) (hash-update! attrs k parse-dimension)) attrs) (define (downcase-values! attrs) ;; make attribute values lowercase, unless they're case-sensitive ;; so we can check them more easily later. (for ([k (in-hash-keys attrs)] #:unless (has-case-sensitive-value? k)) (hash-update! attrs k (λ (val) (match val [(? string? str) (string-downcase str)] [_ val])))) attrs) (define (complete-every-path! attrs) ;; convert every pathlike thing to a complete path (string, because it's inside an attr) ;; so we don't get tripped up later by relative paths ;; 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) ;; various housekeeping on attributes as they are propagated downward during atomization. (for ([proc (in-list (list downcase-values! parse-dimension-strings! complete-every-path! resolve-font-path! resolve-font-size! resolve-font-tracking! resolve-line-height! parse-font-features!))]) (proc attrs))) (define (drop-leading-breaks qs) ;; any leading breaks are pointless at the start of the doc, so drop them. ;; How would we get these? ;; we might, for instance, have a first-level heading style that is specified with page break before. ;; so if we invoke that style first, we will get a page break. (dropf qs break-quad?)) (define default-line-height-multiplier 1.42) (define (setup-qs qx-arg base-dir) ;; convert our input Q-expression into a useful form. ;; some typographic niceties (define qexpr (decode qx-arg #:string-proc (compose1 smart-ellipses smart-dashes) #:txexpr-proc smart-quotes)) ;; apply some default styling attributes. ;; These will only be used if the underlying q-expression hasn't specified its own values, ;; which will naturally override these. (define q (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! base-dir) (let* ([qs (atomize q #:attrs-proc handle-cascading-attrs #:missing-glyph-action 'fallback #:fallback "fallback" #:emoji "fallback-emoji" #:math "fallback-math" #:font-path-resolver resolve-font-path!)] [qs (time-log hyphenate (apply append (map handle-hyphenate qs)))] [qs (map generic->typed-quad qs)] [qs (drop-leading-breaks qs)] [qs (insert-first-line-indents qs)]) 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 (setup-pdf-metadata! qs pdf) (define kv-dict (cons (cons 'Creator (format "Racket ~a [Quad library]" (version))) (for*/list ([(k pdf-k) (in-dict (list (cons :pdf-title 'Title) (cons :pdf-author 'Author) (cons :pdf-subject 'Subject) (cons :pdf-keywords 'Keywords)))] [str (in-value (and (pair? qs) (quad-ref (car qs) k)))] #:when str) (cons pdf-k str)))) (for ([(k v) (in-dict kv-dict)]) (hash-set! (pdf-info pdf) k v))) (define (footnote-flow? q) (equal? (quad-ref q 'flow) "footnote")) (define (make-lines qs line-wrap-size) (define-values (fn-qs main-qs) (partition footnote-flow? qs)) (define line-qs (time-log line-wrap (apply-keeps (line-wrap main-qs line-wrap-size)))) (define fn-line-qs (time-log fn-line-wrap (apply-keeps (line-wrap fn-qs line-wrap-size)))) (values line-qs fn-line-qs)) (define (make-columns line-qs fn-line-qs line-wrap-size printable-height column-gap) (define col-quad-prototype (quad-copy q:column [size (pt line-wrap-size printable-height)])) (time-log column-wrap (column-wrap line-qs fn-line-qs printable-height column-gap col-quad-prototype))) (define (make-pages column-qs left-margin top-margin gutter-margin line-wrap-size printable-width printable-height) (define (page-quad-prototype page-count) (define left-shift (+ left-margin (if (odd? page-count) gutter-margin 0))) (quad-copy q:page [shift (pt left-shift top-margin)] [size (pt line-wrap-size printable-height)])) (time-log page-wrap (page-wrap column-qs printable-width page-quad-prototype))) (define (make-sections qs) (for/fold ([sections-acc null] #:result (reverse sections-acc)) ([qs (in-list (filter-split qs section-break-quad?))]) ;; section properties (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)) ;; layout actions (define-values (line-qs fn-line-qs) (make-lines qs line-wrap-size)) (define column-qs (make-columns line-qs fn-line-qs line-wrap-size printable-height column-gap)) (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 (make-pages column-qs left-margin top-margin gutter-margin line-wrap-size printable-width printable-height)) (begin0 (cond ;; ignore empty section [(zero? (length section-pages)) sections-acc] [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 (quad-copy page-from-current-section [elems null])) (define new-section (quad-copy 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 (quad-copy q:section [elems section-pages])) (match sections-acc [(cons previous-section other-sections) (define previous-section-pages (quad-elems previous-section)) ;; we know previous section has pages because we ignore empty sections (define page-from-previous-section (car previous-section-pages)) (define blank-page (quad-copy page-from-previous-section [elems null])) (define updated-previous-section (quad-update! previous-section [elems (append previous-section-pages (list blank-page))])) (list* new-section updated-previous-section other-sections)] [_ (list new-section)])])] [else (define new-section (quad-copy q:section [elems section-pages]) ) (cons new-section sections-acc)]) (section-pages-used (+ (section-pages-used) (length section-pages)))))) (define (correct-line-alignment doc) ;; correct lines with inner / outer alignment (for* ([(page page-idx) (in-indexed (for*/list ([section (in-list (quad-elems doc))] [page (in-list (quad-elems section))]) page))] [col (in-list (quad-elems page))] [block (in-list (quad-elems col))] [line (in-list (quad-elems block))]) ;; all inner / outer lines are initially filled as if they were right-aligned (define zero-filler-side (if (odd? (add1 page-idx)) "inner" "outer")) (when (equal? zero-filler-side (quad-ref line :line-align)) (match (quad-elems line) [(cons (? filler-quad? fq) _) (set-quad-size! fq (pt 0 0))] [_ (void)]))) doc) (define/contract (render-pdf qx-arg [pdf-path-arg #false] [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 boolean? #:compress boolean?) . ->* . (or/c void? bytes?)) ;; The principal public interface to rendering. ;; `qx-arg` is the Q-expression to be rendered. ;; `pdf-path-arg` is the destination of the generated PDF. ;; #false signals that we should return the PDF bytes rather than saving. ;; `base-dir-arg` is the starting point for resolving any relative pathnames, ;; and looking for fonts and other assets. (define base-dir (let ([maybe-dir (cond ;; for reasons unclear, DrRacket sometimes sneaks ;; an "unsaved editor" into base-dir-arg, despite efforts ;; probably my fault [(equal? base-dir-arg "unsaved editor") pdf-path-arg] [base-dir-arg] [pdf-path-arg] [else (current-directory)])]) (match maybe-dir [(? directory-exists? dir) dir] [_ (define-values (dir name _) (split-path maybe-dir)) dir]))) (unless (directory-exists? base-dir) (raise-argument-error 'render-pdf "existing directory" base-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))) ;; `make-pdf` creates a PDF data structure using the pitfall library. ;; this structure provides some services as we lay out the document, ;; and then when we render, we'll rely on pitfall's PDF-drawing routines. (parameterize ([current-pdf (make-pdf #:compress compress? #:auto-first-page #false #:output-path pdf-path)] ;; set `current-directory` so that ops like `path->complete-path` ;; will be handled relative to the original directory [current-directory base-dir] ;; a lot of operations need to look at pages used so it's easier to ;; make it a parameter than endlessly pass it around as an argument. [section-pages-used 0] [verbose-quad-printing? #false]) ; for ease of debugging; not mandatory (define qs (time-log setup-qs (setup-qs qx-arg base-dir))) (setup-pdf-metadata! qs (current-pdf)) ;; all the heavy lifting happens inside `make-sections` ;; which calls out to `make-pages`, `make-columns`, and so on. (define doc (correct-line-alignment (quad-copy q:doc [elems (make-sections qs)]))) ;; call `position` and `draw` separately so we can print a timer for each (define positioned-doc (time-log position (position doc))) ;; drawing implies that a PDF is written to disk (time-log draw (draw positioned-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))))