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#lang debug racket
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(require quad/quad
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"struct.rkt"
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"param.rkt"
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"debug.rkt"
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"font.rkt"
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"string.rkt"
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"attrs.rkt"
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quad/base
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sugar/list
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pitfall
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racket/unsafe/ops)
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(provide (all-defined-out))
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(define (hr-draw dq doc)
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(match-define (list left top) (quad-origin dq))
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(match-define (list right bottom) (size dq))
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(save doc)
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(translate doc left (+ top (/ bottom 2.0)))
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(move-to doc 0 0)
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(line-to doc right 0)
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(line-width doc 0.5)
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(stroke doc "black")
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(restore doc))
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(define (make-hr-quad line-q)
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(quad-copy line-quad line-q [draw-start hr-draw]))
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(define q:line (make-quad
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#:type line-quad
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#:size (pt 0 default-line-height)
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#:from 'sw
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#:to 'nw
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#:printable #true
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#:tag 'line
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#:draw-start (if draw-debug-line? draw-debug void)))
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(define (render-hyphen qs ending-q)
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;; naive handling of soft hyphen:
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;; if soft hyphen cause the break, then append a printing hyphen to the end of the run.
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;; this assumes that there is room for the hyphen on the line
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;; and does not take into account hyphen-break transformations found in other languages.
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;; However we do want the hyphen joined into the string so the final shaping / positioning is correct
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;; for instance, kerning between last letter and hyphen.
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(match (and ending-q (equal? (quad-elems ending-q) '("\u00AD")) qs)
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[(list head ... last-q)
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(define str (car (quad-elems last-q)))
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(define str+hyphen (string-append str "-"))
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(append head
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(list (quad-update! last-q
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[elems (list str+hyphen)]
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[size (make-size-promise-for-string last-q str+hyphen)])))]
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[_ qs]))
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(define (space-quad? q) (equal? (quad-elems q) (list " ")))
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(define (hang-punctuation nonspacess)
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(match nonspacess
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[(list sublists ... (list prev-qs ... last-q))
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#:when (pair? (quad-elems last-q))
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(match (regexp-match #rx"[.,:;’-]$" (car (quad-elems last-q)))
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[#false nonspacess]
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[last-char-str
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(define hanger-q (quad-copy string-quad last-q
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[elems null]
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[size (let ([p (make-size-promise-for-string last-q (car last-char-str))])
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(delay
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(match-define (list x y) (force p))
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(pt (- x) y)))]))
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(define last-sublist (append prev-qs (list last-q hanger-q)))
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(append sublists (list last-sublist))])]
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[_ nonspacess]))
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(define (sum-sum-x qss)
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(for/sum ([qs (in-list qss)])
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(sum-x qs)))
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(define (tracking-adjustment q)
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(match q
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[(? string-quad?) (/ (quad-ref q :font-tracking 0) 2.0)]
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[_ 0]))
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(define (line-height-from-qs qs)
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;; line height is the max 'line-height value or the natural height of q:line
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(match (filter-map (λ (q) (or (quad-ref q :line-height) (pt-y (size q)))) qs)
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[(? null?) #false]
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[line-heights (apply max line-heights)]))
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(define (fill-line-wrap all-qs line-prototype last-line-in-paragraph?)
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;; happens during the finish of a line wrap, before consolidation of runs
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(unless (pair? all-qs)
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(raise-argument-error 'fill-line-wrap "nonempty list of quads" all-qs))
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;; remove anchored quads because they don't affect line layout
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(define-values (absolute-qs qs) (partition (λ (q) (quad-ref q :parent)) all-qs))
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(match qs
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[(? null?) absolute-qs]
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[(and (cons q-first other-qs) (list _ ... q-last))
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(define align-value (quad-ref q-first :line-align "left"))
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;; words may still be in hyphenated fragments
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;; (though soft hyphens would have been removed)
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;; so group them (but no need to consolidate — that happens elsewhere)
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(define-values (spacess nonspacess) (partition* space-quad? qs))
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(match (length nonspacess)
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[1 #:when (equal? align-value "justify") qs] ; can't justify single word
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[nonspacess-count
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(match-define (list line-prototype-width line-prototype-height) (quad-size line-prototype))
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(define hung-nonspacess (hang-punctuation nonspacess))
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(define left-tracking-adjustment (tracking-adjustment q-first))
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(define right-tracking-adjustment (tracking-adjustment q-last))
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(define nonspace-total-width
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(- (sum-sum-x hung-nonspacess) left-tracking-adjustment right-tracking-adjustment))
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(define space-total-width (sum-sum-x spacess))
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(define empty-hspace (- line-prototype-width
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(quad-ref q-first :inset-left 0)
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nonspace-total-width
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(quad-ref q-first :inset-right 0)))
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(define (make-left-edge-filler [width 0])
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(make-quad #:type filler-quad
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#:tag 'line-filler
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#:from-parent (quad-from-parent q-first)
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#:from 'bo
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#:to 'bi
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#:shift (pt (- left-tracking-adjustment) 0)
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#:size (pt width 0)
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#:attrs (quad-attrs q-first)))
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(cond
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[(or
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(and (equal? align-value "justify") (or (not last-line-in-paragraph?)
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;; don't justify the last line in a paragraph
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;; unless empty space is less than 17% of width (an arbitrary visual threshold)
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(< (/ empty-hspace line-prototype-width 1.0) .17)))
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(let ([line-overfull? (negative? (- empty-hspace space-total-width))])
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;; force justification upon overfull lines,
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;; which amounts to shrinking the word spaces till the line fits
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(and line-overfull? (> nonspacess-count 1))))
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(define justified-space-width (/ empty-hspace (sub1 nonspacess-count)))
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(define justified-spacer (make-quad
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#:from 'bo
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#:to 'bi
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#:draw-end q:string-draw-end
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#:size (pt justified-space-width (or (line-height-from-qs (append* hung-nonspacess)) line-prototype-height))))
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(cons (make-left-edge-filler) (apply append (add-between hung-nonspacess (list justified-spacer))))]
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[else
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(define space-multiplier (match align-value
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["center" 0.5]
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;; fill inner & outer as if they were right,
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;; they will be corrected later, when pagination is known.
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[(or "right" "inner" "outer") 1]
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;; "left" and "justify" are handled here
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[_ 0]))
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;; subtact space-width because that appears between words
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;; we only care about redistributing the space on the ends
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(define end-hspace (- empty-hspace space-total-width))
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;; make filler a leading quad, not a parent / grouping quad,
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;; so that elements can still be reached by consolidate-runs
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(list* (make-left-edge-filler (* end-hspace space-multiplier))
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(quad-update! q-first [from-parent #f])
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;; ok to put back absolute quads at end, because it doesn't affect their layout
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(append other-qs absolute-qs))])])]))
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(define (make-paragraph-spacer maybe-first-line-q key default-val)
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(define arbitrary-width 20)
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(make-quad #:type line-spacer-quad
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#:size (pt arbitrary-width (cond
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[(and maybe-first-line-q (quad-ref maybe-first-line-q key))]
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[else default-val]))
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#:from 'sw
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#:to 'nw
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#:printable only-prints-in-middle
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#:draw-start (if (draw-debug-line?) draw-debug void)))
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(define ((line-wrap-finish line-prototype-q default-block-id) wrap-qs q-before q-after idx)
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;; we curry line-q so that the wrap size can be communicated to this operation
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;; remove unused soft hyphens so they don't affect final shaping
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(define wrap-qs-printing (for/list ([wq (in-list wrap-qs)]
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#:unless (equal? (quad-elems wq) '("\u00AD")))
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wq))
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(define new-lines
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(cond
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[(empty? wrap-qs-printing) null]
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[(hr-break-quad? q-after) (list (make-hr-quad line-prototype-q))]
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[else
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;; render hyphen first so that all printable characters are available for size-dependent ops.
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(define pcs-with-hyphen (render-hyphen wrap-qs-printing q-after))
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;; fill wrap so that consolidate-runs works properly
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;; (justified lines won't be totally consolidated)
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(define last-line-in-paragraph? (not q-after))
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(define pcs (fill-line-wrap pcs-with-hyphen line-prototype-q last-line-in-paragraph?))
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(match (consolidate-runs pcs)
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[(and (cons elem-first _) elems)
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(match-define (list line-width line-height) (quad-size line-prototype-q))
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(list
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(quad-copy line-quad line-prototype-q
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;; move block attrs up, so they are visible in col wrap
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[attrs (let ([h (copy-block-attrs (quad-attrs elem-first) (hash-copy (quad-attrs line-prototype-q)))])
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;; we want every group of lines in a paragraph to have a block id
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;; so that it will be wrapped as a block later.
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;; we only set this if there is no value for :display.
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(hash-ref! h :display default-block-id)
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h)]
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;; line width is static
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[size (pt line-width (or (line-height-from-qs pcs) line-height))]
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;; handle list indexes. drop new quad into line to hold list index
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;; could also use this for line numbers
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[elems
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;; we assume here that a list item has already had extra inset-left
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;; with room for a bullet
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;; which we just insert at the front.
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;; this is safe because line has already been filled.
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(append
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;; only put bullet into line if we're at the first line of the list item
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(match (and (eq? idx 1) (quad-ref elem-first :list-index))
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[#false null]
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[bullet
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(define bq (quad-copy string-quad q:string ;; copy q:string to get draw routine
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;; borrow attrs from elem
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[attrs (quad-attrs elem-first)]
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;; use bullet as elems
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[elems (list (if (number? bullet) (format "~a." bullet) bullet))]
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;; size doesn't matter because nothing refers to this quad
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;; just for debugging box
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[size (pt 15 (pt-y (size line-prototype-q)))]))
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(from-parent (list bq) 'sw)])
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(from-parent
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(match (quad-ref elem-first :inset-left 0)
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[0 elems]
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[inset-val (cons (make-quad
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#:draw-end q:string-draw-end
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#:to 'sw
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#:size (pt inset-val 5)
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#:type offsetter-quad)
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elems)]) 'sw))]))]
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[_ null])]))
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(define maybe-first-line (and (pair? new-lines) (car new-lines)))
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(append (match q-before
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[#false (list (make-paragraph-spacer maybe-first-line :space-before 0))] ; paragraph break
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[_ null])
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new-lines
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(match q-after
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[(? column-break-quad? column-break) (list column-break)] ; hard column (or section or page) break
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[#false
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(define default-paragraph-spacing (* default-line-height 0.6))
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(list (make-paragraph-spacer maybe-first-line :space-after default-paragraph-spacing))] ; paragraph break
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[_ null]))) ; hard line break
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(define softies (map string '(#\space #\- #\u00AD)))
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(define (soft-break-for-line? q)
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(and (pair? (quad-elems q))
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(member (unsafe-car (quad-elems q)) softies)))
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(define (permitted-justify-overfill q)
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(match (quad-ref q :line-align)
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;; allow justified lines to go wider,
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;; and then fill-wrap will tighten thes word spaces
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;; this makes justified paragraphs more even, becuase
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;; some lines are a little tight, as opposed to all of them being loose
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;; this has to be based on a certain quad, not set globally for the line-wrap operation,
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;; because different lines might have different alignment settings.
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["justify" 1.025]
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[_ 1]))
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(define (line-wrap qs wrap-size [debug #false])
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(unless (positive? wrap-size)
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(raise-argument-error 'line-wrap "positive number" wrap-size))
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(match qs
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[(cons q _)
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;; group lines into sublists separated by para-breaks, but then omit the para-breaks themselves
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;; because they've served their purpose (leave the others, to be expressed later)
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;; however, leave line-breaks in, because they will be handled by wrap.
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(define para-qss (let loop ([qs qs][acc null])
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(match qs
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[(? null?) (reverse acc)]
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[(cons (? para-break-quad?) rest)
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(loop rest acc)]
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[(cons (? column-break-quad? bq) rest)
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(loop rest (cons bq acc))]
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[(list* (and (not (? para-break-quad?)) nbqs) ... rest)
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(loop rest (cons nbqs acc))])))
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(define res
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(apply append
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(for/list ([para-qs (in-list para-qss)])
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(define block-id (gensym))
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(match para-qs
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[(? break-quad? bq) (list bq)]
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[(cons pq _)
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(define line-q-for-this-paragraph
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(quad-copy line-quad
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q:line
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[size (pt wrap-size (quad-ref pq :line-height default-line-height))]))
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(wrap para-qs
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(* (- wrap-size
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(quad-ref pq :inset-left 0)
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(quad-ref pq :inset-right 0))
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(permitted-justify-overfill pq))
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debug
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;; during wrap, anchored qs are treated as having distance 0
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;; so they can staty in right place, so that relative queries will work.
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;; but they won't affect where lines break
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#:distance (λ (q last-dist wrap-qs)
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(+ last-dist (cond
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[(quad-ref q :parent) 0]
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[(printable? q) (distance q)]
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[else 0])))
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#:nicely (match (or (current-line-wrap) (quad-ref pq :line-wrap))
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[(or "best" "kp") #true]
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[_ #false])
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#:hard-break line-break-quad?
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#:soft-break soft-break-for-line?
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#:finish-wrap (line-wrap-finish line-q-for-this-paragraph block-id))]))))
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res]
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[_ null]))
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