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typesetting/quad/quadwriter/string.rkt

124 lines
5.2 KiB
Racket

#lang debug racket
(require "struct.rkt"
"font.rkt"
"attrs.rkt"
"param.rkt"
"debug.rkt"
quad/quad
quad/atomize
pitfall
quad/position
racket/unsafe/ops)
(provide (all-defined-out))
(define (convert-string-quad q)
;; need to handle casing here so that it's reflected in subsequent sizing ops
(define cased-str (match (quad-elems q)
[(cons str _)
(define proc (match (quad-ref q :font-case)
[(or "upper" "uppercase") string-upcase]
[(or "lower" "lowercase" "down" "downcase") string-downcase]
[(or "title" "titlecase") string-titlecase]
[_ values]))
(proc str)]
[_ ""])) ; a string quad should always contain a string
(quad-copy string-quad q:string
[attrs (let ([attrs (quad-attrs q)])
(hash-ref! attrs :font-size default-font-size)
attrs)]
[elems (list cased-str)]
[size (make-size-promise-for-string q cased-str)]))
(define soft-hyphen-string "\u00AD")
(define (make-size-promise-for-string q [str-arg #f])
;; we know sensible defaults for all text properties have been set up during atomization.
(delay
(define q-string-width
(let ([str (cond
[str-arg]
[else (match (quad-elems q)
[(cons q _) q]
[_ #false])])])
(cond
[(positive? (string-length str))
(define pdf (current-pdf))
(font-size pdf (quad-ref q :font-size))
(font pdf (path->string (quad-ref q font-path-key)))
(define tracking-val (quad-ref q :font-tracking 0))
(cond
[(equal? str soft-hyphen-string) tracking-val]
[else ;; `string-width` only applies tracking between glyphs.
;; we add an extra tracking-val because we want to count tracking on every glyph.
;; because at this stage, we don't know whether the quad will be freestanding or adjacent to another
;; probably adjacent. And if so, it should have half tracking on the ends, full tracking in between
(+ (string-width pdf str
#:tracking tracking-val
#:features (quad-ref q :font-features))
tracking-val)])]
[else 0])))
(list q-string-width (quad-ref q :line-height))))
(define (q:string-draw q doc
#:origin [origin-in #f]
#:text [str-in #f])
(match (or str-in (and (pair? (quad-elems q)) (unsafe-car (quad-elems q))))
[#false (void)]
[str
(font doc (path->string (quad-ref q font-path-key default-font-face)))
(font-size doc (quad-ref q :font-size default-font-size))
(fill-color doc (quad-ref q :font-color default-font-color))
(match-define (list x y) (or origin-in (quad-origin q)))
(define tracking (quad-ref q :font-tracking 0))
;; we adjust x by half tracking because by convention, string quads have half tracking at beginning & end
;; whereas PDF drawing only puts tracking between the glyphs.
(text doc str (+ x (/ tracking 2.0)) (- y (quad-ref q :font-baseline-shift 0))
#:tracking tracking
#:bg (quad-ref q :bg)
#:features (quad-ref q :font-features default-font-features)
#:link (quad-ref q :link))]))
(define (q:string-draw-end q doc)
(when (draw-debug-string?)
(draw-debug q doc "#99f" "#ccf")))
(define (q:string-printable? q [sig #f])
;; printable unless single space, which is not printable at start or end
(match (quad-elems q)
[(cons elem _)
(case elem
[(" " #\space) (not (memq sig '(start end)))]
[else #true])]
[_ #true]))
(define q:string (q #:type string-quad
#:from 'bo
#:to 'bi
#:tag 'str
#:printable q:string-printable?
#:draw q:string-draw
#:draw-end q:string-draw-end))
(define (consolidate-runs pcs)
(let loop ([runs empty][pcs pcs])
(match pcs
[(cons (? string-quad? strq) rest)
(define-values (run-pcs rest) (splitf-at pcs (λ (p) (same-run? strq p))))
;; run-pcs has at least one element (strq)
;; and the other members are part of the same run.
;; meaning, they share the same formatting, including character tracking.
;; we add a tracking adjustment because it only "appears"
;; once characters are consolidated
(define tracking-adjustment
(* (sub1 (length run-pcs)) (quad-ref (car run-pcs) :font-tracking 0)))
(define new-run
(quad-copy string-quad q:string
[attrs (quad-attrs strq)]
[elems (merge-adjacent-strings (apply append (map quad-elems run-pcs)))]
[size (delay (pt (sum-x run-pcs) (pt-y (size strq))))]))
(loop (cons new-run runs) rest)]
[(cons first rest) (loop (cons first runs) rest)]
[_ (reverse runs)])))