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typesetting/quad/wrap-typed.rkt

592 lines
31 KiB
Racket

#lang typed/racket/base
(require (for-syntax racket/base racket/syntax))
(require/typed sugar/list [slicef-after ((Listof Quad) (Quad . -> . Boolean) . -> . (Listof (Listof Quad)))]
[shift ((Listof Any) (Listof Integer) . -> . (Listof Any))]
[break-at ((Listof Quad) (Listof Nonnegative-Integer) . -> . (Listof (Listof Quad)))])
(require math/flonum (except-in racket/list flatten) racket/vector math/statistics)
(require/typed racket/list [flatten (All (A) (Rec as (U Any (Listof as))) -> (Listof Any))])
(require "ocm-typed.rkt" "quads-typed.rkt" "utils-typed.rkt" "measure-typed.rkt" "world-typed.rkt" "logger-typed.rkt")
;; predicate for the soft hyphen
(define/typed (soft-hyphen? x)
(String . -> . Boolean)
(equal? (format "~a" world:soft-hyphen) x))
;; visible characters that also mark possible breakpoints
(define/typed (visible-breakable? x)
(String . -> . Boolean)
(and (member x world:hyphens-and-dashes) #t))
;; invisible characters that denote possible breakpoints
(define/typed (invisible-breakable? x)
(String . -> . Boolean)
(and (member x (cons world:empty-string world:spaces)) #t))
;; union of visible & invisible
(define/typed (breakable? x)
(Any . -> . Boolean)
(cond
[(string? x) (or (visible-breakable? x) (invisible-breakable? x))]
[(word? x) (breakable? (word-string (cast x Quad)))]
[else #f]))
;; used by insert-spacers to determine which characters
;; can be surrounded by stretchy spacers
(define/typed (takes-justification-space? x)
(Any . -> . Boolean)
(whitespace/nbsp? x))
;; test if a quad can be a word break:
;; either it's an explicit word break,
;; or it's breakable (and can be converted to a word break)
(define/typed (possible-word-break-quad? q)
(Quad . -> . Boolean)
(or (word-break? q) (breakable? q)))
;; convert a possible word break into an actual one
(define/typed (convert-to-word-break q)
(Quad . -> . Quad)
(when (not (possible-word-break-quad? q))
(error 'convert-to-word-break "input is not a possible word break:" q))
(define result (cond
[(word-break? q) q]
[(word? q)
(define str (word-string q)) ; str will be one character long, because we've exploded our input
(apply word-break
(merge-attrs q ; take q's attributes for formatting purposes
(cond
;; a space is ordinarily visible, but disappears at the end of a line
[(equal? str " ") (list world:no-break-key " " world:before-break-key "")]
;; soft hyphen is ordinarily invisible, but appears at the end of a line
[(soft-hyphen? str) (list world:no-break-key "" world:before-break-key "-")]
;; a visible breakable character is always visible
[(visible-breakable? str) (list world:no-break-key str world:before-break-key str)]
[else (cast (world:default-word-break-list) HashableList)])) (quad-list q))]
[else #f]))
(or result (error 'convert-to-word-break "result was a not word break for input:" q)))
(define/typed (make-unbreakable q)
(Quad . -> . Quad)
(quad-attr-set q world:unbreakable-key #t))
;; take list of atomic quads and gather them into pieces
;; a piece is an indivisible chunk of a line.
;; meaning, a line can wrap at a piece boundary, but not elsewhere.
;; hyphenation produces more, smaller pieces, which means more linebreak opportunities
;; but this also makes wrapping slower.
(define-type Make-Pieces-Type ((Listof Quad) . -> . (Listof Quad)))
(define/typed (make-pieces qs)
Make-Pieces-Type
(define-values (breakable-items items-to-make-unbreakable) (split-at-right qs (min world:minimum-last-line-chars (length qs))))
(define unbreak-qs (append breakable-items (map make-unbreakable items-to-make-unbreakable)))
(define lists-of-quads (slicef-after unbreak-qs (λ(q) (and (possible-word-break-quad? (cast q Quad)) (not (quad-attr-ref (cast q Quad) world:unbreakable-key #f))))))
(define-values (first-lists-of-quads last-list-of-quads) ((inst split-last (Listof Quad)) lists-of-quads))
(define/typed (make-first-pieces qs)
((Listof Quad) . -> . Quad)
(let-values ([(first-qs last-q) ((inst split-last Quad) qs)])
(apply piece (list world:word-break-key (convert-to-word-break (cast last-q Quad))) (cast first-qs QuadList))))
(append (map make-first-pieces first-lists-of-quads)
(list (apply piece #f (cast last-list-of-quads QuadList)))))
;; extract font attributes from quad, or get default values
(define/typed (font-attributes-with-defaults q)
(Quad . -> . (List Nonnegative-Float String Symbol Symbol))
(list
(cast (let ([size (quad-attr-ref/parameter q world:font-size-key)])
(if (exact-integer? size) (fl size) size)) Nonnegative-Float)
(cast (quad-attr-ref/parameter q world:font-name-key) String)
(cast (quad-attr-ref/parameter q world:font-weight-key) Symbol)
(cast (quad-attr-ref/parameter q world:font-style-key) Symbol)))
;; get the width of a quad.
;; Try the attr first, and if it's not available, compute the width.
;; comes in fast or slow versions.
;; not designed to update the source quad.
(define-type Measure-Quad-Type (Quad . -> . Float))
(define/typed (quad-width q)
Measure-Quad-Type
(cond
[(quad-has-attr? q world:width-key) (fl (cast (quad-attr-ref q world:width-key) Real))]
[(ormap (λ([pred : (Any . -> . Boolean)]) (pred q)) (list char? run? word? word-break?))
(apply measure-text (word-string q)
(font-attributes-with-defaults q))]
[(line? q) (fl (apply + ((inst map Float Quad) quad-width (cast (quad-list q) (Listof Quad)))))]
[else 0.0]))
;; get the ascent (distance from top of text to baseline)
;; used by renderer to align text runs baseline-to-baseline.
;; consult the attrs, and if not available, compute it.
;; not designed to update the source quad.
(define/typed (ascent q)
(Quad . -> . Float)
(define ascent-value-or-false (quad-attr-ref q world:ascent-key #f))
(if ascent-value-or-false
(cast ascent-value-or-false Float)
(cond
[(ormap (λ([pred : (Any . -> . Boolean)]) (pred q)) (list char? run? word? word-break?))
(apply measure-ascent (word-string q) (font-attributes-with-defaults q))]
[else 0.0])))
;; convert a piece into its final form, which depends on location.
;; if a piece appears at the end of a line, it is rendered in "before break" mode.
;; if a piece appears elsewhere in a line, it is rendered in "no break" mode.
;; this allows the appearance of a piece to change depending on whether it's at the end.
;; and thus give correct behavior to trailing word spaces, soft hyphens, etc.
(define/typed (render-piece p [before-break? #f])
((Quad) (Boolean) . ->* . Quad)
;; a piece doesn't necessarily have a word-break item in it.
;; only needs it if the appearance of the piece changes based on location.
;; so words are likely to have a word-break item; boxes not.
;; the word break item contains the different characters needed to finish the piece.
(define the-word-break (cast (quad-attr-ref p world:word-break-key #f) (Option Quad)))
(let ([p (quad-attr-remove p world:word-break-key)]) ; so it doesn't propagate into subquads
(if the-word-break
(quad (quad-name p) (quad-attrs p)
(append (quad-list p) (let ([rendered-wb ((if before-break?
word-break->before-break
word-break->no-break) the-word-break)])
(if (> (string-length (word-string rendered-wb)) 0) ; if rendered-wb is "", don't append it
(list rendered-wb)
empty))))
p)))
;; shorthand
(define/typed (render-piece-before-break p)
(Quad . -> . Quad)
(render-piece p #t))
;; helper macro to convert quad into word-break.
;; look up the break character and convert the quad based on what is found.
(define/typed (render-word-break wb key)
(Quad Symbol . -> . Quad)
(let ([break-char (quad-attr-ref wb key)])
(quad (if (whitespace? break-char) 'word-break 'word)
(hash-remove (hash-remove (quad-attrs wb) world:no-break-key) world:before-break-key) (list (cast (quad-attr-ref wb key) String)))))
;; uses macro above in no-break mode.
(define/typed (word-break->no-break wb)
(Quad . -> . Quad)
(render-word-break wb world:no-break-key))
;; uses macro above in before-break mode.
(define/typed (word-break->before-break wb)
(Quad . -> . Quad)
(render-word-break wb world:before-break-key))
;; is this the last line? compare current line-idx to total lines
(define/typed (last-line? line)
(Quad . -> . Boolean)
(define line-idx (cast (quad-attr-ref line world:line-index-key #f) Number))
(define lines (cast (quad-attr-ref line world:total-lines-key #f) Number))
(and line-idx lines (= (add1 line-idx) lines)))
;; optical kerns are automatically inserted at the beginning and end of a line
;; (by the pieces->line function)
;; but may also be found elsewhere, imperatively (e.g., before an indent)
;; they allow certain characters to hang over the line margin.
;; optical kerns aren't considered when the line is being composed,
;; rather they are an adjustment added to a composed line.
;; the optical kern doesn't have left- or right-handed versions.
;; it just looks at quads on both sides and kerns them if appropriate.
;; in practice, only one will likely be used.
(define/typed (render-optical-kerns exploded-line-quads)
((Listof Quad) . -> . (Listof Quad))
(define/typed (overhang-width q)
((U Quad False) . -> . Float)
(if (and (word? q) (member (word-string (cast q Quad)) world:hanging-chars))
(* -1.0 (world:optical-overhang) (apply measure-text (word-string (cast q Quad)) (font-attributes-with-defaults (cast q Quad))))
0.0))
(cond
[(not (empty? exploded-line-quads))
;; after exploding, each quad will have a string with one character.
(define shifted-lists (shift exploded-line-quads '(1 0 -1)))
(define lefts (cast (first shifted-lists) (Listof (U Quad False)))) ;; need False in type because shift fills with #f
(define centers (cast (second shifted-lists) (Listof Quad))) ;; don't need False because shift is 0 (no fill)
(define rights (cast (third shifted-lists) (Listof (U Quad False)))) ;; need False in type because shift fills with #f
(for/list : (Listof Quad) ([(q-left q q-right) (in-parallel lefts centers rights)])
(if (optical-kern? q)
(quad-attr-set q world:width-key (fl+ (overhang-width q-left) (overhang-width q-right)))
q))]
[else exploded-line-quads]))
;; ultimately every line is filled to fit the whole measure.
;; spacers are used to soak up extra space left over in a line.
;; depending on where the spacers are inserted, different formatting effects are achieved.
;; e.g., left / right / centered / justified.
(define/typed+provide (insert-spacers-in-line line [alignment-override #f])
((Quad) ((Option Symbol)) . ->* . Quad)
;; important principle: avoid peeking into quad-list to get attributes.
;; because non-attributed quads may be added.
;; here, we know that common attributes are hoisted into the line.
;; so rely on line attributes to get horiz alignment.
(define key-to-use (if (and (last-line? line) (quad-has-attr? line world:horiz-alignment-last-line-key))
world:horiz-alignment-last-line-key
world:horiz-alignment-key))
(define horiz-alignment (or alignment-override (quad-attr-ref line key-to-use (world:horiz-alignment-default))))
(define default-spacer (spacer))
(define-values (before middle after) (case horiz-alignment
[(left) (values #f #f default-spacer)]
[(right) (values default-spacer #f #f)]
[(center) (values default-spacer #f default-spacer)]
[(justified justify) (values #f default-spacer #f)]
[else (values #f #f #f)]))
(define/typed (copy-with-attrs q attr-source)
(Quad Quad . -> . Quad)
(define keys-to-ignore '(width)) ; width will be determined during fill routine
(define filtered-hash (cast (and (quad-attrs attr-source)
(foldl (λ(k [ht : HashTableTop]) (hash-remove ht k)) (quad-attrs attr-source) keys-to-ignore)) QuadAttrs))
(quad (quad-name q) (merge-attrs filtered-hash q) (quad-list q)))
(quad (quad-name line)
(quad-attrs line)
(cast (flatten (let ([qs (cast (quad-list line) (Listof Quad))])
;; (first qs) is a single quad, but wrap it in a list to make it spliceable
`(,@(cast (if before (list (copy-with-attrs before (first qs))) null) (Listof Quad))
,@(map (λ([q : Quad]) (if (and middle (takes-justification-space? q))
(let ([interleaver (copy-with-attrs middle q)])
(list interleaver q interleaver))
q)) qs)
;; (last qs) is a single quad, but wrap it in a list to make it spliceable
,@(cast (if after (list (copy-with-attrs after (last qs))) null) (Listof Quad))
))) QuadList)))
;; installs the width in the quad.
;; this becomes the value reported by quad-width.
(define/typed (embed-width q w)
(Quad Float . -> . Quad)
(quad-attr-set q world:width-key w))
;; installs the ascent in the quad.
(define/typed (record-ascent q)
(Quad . -> . Quad)
(quad-attr-set q world:ascent-key (ascent q)))
;; helper function: doesn't need contract because it's already covered by the callers
(define/typed (render-pieces ps)
((Listof Quad) . -> . (Listof Quad))
(define-values (initial-ps last-p) (split-last ps))
(snoc ((inst map Quad Quad) render-piece (cast initial-ps (Listof Quad))) (render-piece-before-break (cast last-p Quad))))
(define/typed (calc-looseness total-width measure)
(Float Float . -> . Float)
(round-float (fl/ (fl- measure total-width) measure)))
;; compose pieces into a finished line.
;; take the contents of the rendered pieces and merge them.
;; compute looseness for line as a whole.
;; also add ascent to each component quad, which can be different depending on font & size.
(define-type Compose-Line-Type ((Listof Quad) (Quad . -> . Float) . -> . Quad))
(define/typed (pieces->line ps measure-quad-proc)
Compose-Line-Type
;; handle optical kerns here to avoid resplitting and rejoining later.
(define rendered-pieces (render-pieces ps))
(define split-pieces (map quad-list rendered-pieces))
(define line-quads (cast (append* split-pieces) (Listof Quad)))
(define line-quads-maybe-with-opticals
(if world:use-optical-kerns?
(render-optical-kerns
(let ([my-ok (list (optical-kern (quad-attrs (car line-quads))))]) ; take attrs from line, incl measure
(append my-ok line-quads my-ok)))
line-quads))
(define merged-quads (join-quads line-quads-maybe-with-opticals))
(define merged-quad-widths (map measure-quad-proc merged-quads)) ; 10% of function time
(log-quad-debug "making pieces into line = ~v" (apply string-append (map quad->string merged-quads)))
;; if measure key isn't present, allow an error, because that's weird
(when (not (quad-has-attr? (first line-quads) world:measure-key))
(error 'pieces->line "quad has no measure key: ~a" (first line-quads)))
(define measure (cast (quad-attr-ref (first merged-quads) world:measure-key) Float))
(define looseness (calc-looseness (fl (apply + merged-quad-widths)) measure))
;; quads->line function hoists common attributes into the line
(let* ([new-line-quads (map embed-width merged-quads merged-quad-widths)] ; 15% of time
[new-line-quads (map record-ascent new-line-quads)] ; 35% of time
[new-line (quads->line new-line-quads)]
[new-line (quad-attr-set new-line world:line-looseness-key looseness)])
new-line))
;; a faster line-measuring function used by the wrapping function to test lines.
(define/typed (measure-potential-line ps)
((Listof Quad) . -> . Float)
(cast (for*/sum : (U Float Zero)
([rendered-piece (in-list (render-pieces ps))]
[piece-quad (in-list (quad-list rendered-piece))])
(quad-width (cast piece-quad Quad))) Float))
(define/typed (vector-break-at vec bps)
((Vectorof Any) (Listof Nonnegative-Integer) . -> . (Listof (Vectorof Any)))
(define-values (vecs _) ;; loop backward
(for/fold ([vecs : (Listof (Vectorof Any)) empty][end : Nonnegative-Integer (vector-length vec)])([start (in-list (reverse (cons 0 bps)))])
(if (= start end)
(values vecs start)
(values (cons ((inst vector-copy Any) vec start end) vecs) start))))
vecs)
;; makes a wrap function by combining component functions.
(define-type Wrap-Proc-Type (((Listof Quad)) (Float) . ->* . (Listof Quad)))
(define/typed (make-wrap-proc
make-pieces-proc
measure-quad-proc
compose-line-proc
find-breakpoints-proc)
((Make-Pieces-Type Measure-Quad-Type Compose-Line-Type Find-Breakpoints-Type) () . ->* . Wrap-Proc-Type)
(λ(qs [measure #f])
(let* ([measure : Float (fl+ (cast (or measure (quad-attr-ref/parameter (car qs) world:measure-key)) Float) 0.0)]
[qs : (Listof Quad) (if (quad-has-attr? (car qs) world:measure-key)
qs
((inst map Quad Quad) (λ(q) (quad-attr-set q world:measure-key measure)) qs))])
(log-quad-debug "wrapping on measure = ~a" measure)
(define pieces : (Listof Quad) (make-pieces-proc qs)) ; 5%
(define bps : (Listof Nonnegative-Integer) (find-breakpoints-proc (list->vector pieces) measure)) ; 50%
(define broken-pieces : (Listof (Listof Quad)) (break-at pieces bps)) ; 5%
#; (define-type Compose-Line-Type ((Listof Quad) (Quad . -> . Float) . -> . Quad))
((inst map Quad (Listof Quad)) (λ(broken-piece) (compose-line-proc broken-piece measure-quad-proc)) broken-pieces)))) ; 50%
(define width? flonum?)
(define measure? flonum?)
(define (breakpoints? x) (and (list? x) (andmap integer? x)))
(define/typed (install-measurement-keys p)
(Quad . -> . Quad)
(define basic-width (round-float (apply + ((inst map Float Quad) quad-width (cast (quad-list p) (Listof Quad))))))
(define p-word-break (cast (quad-attr-ref p world:word-break-key #f) Quad))
(define before-break-width (fl+ basic-width (if p-word-break
(quad-width (word (quad-attrs p-word-break) (cast (quad-attr-ref p-word-break world:before-break-key) QuadListItem)))
0.0)))
(define no-break-width (fl+ basic-width (if p-word-break
(quad-width (word (quad-attrs p-word-break) (cast (quad-attr-ref p-word-break world:no-break-key) QuadListItem)))
0.0)))
(quad-attr-set* p 'bb-width before-break-width 'nb-width no-break-width))
(require sugar/debug)
(define/typed (make-piece-vectors pieces)
((Vectorof Quad) . -> . (values (Vectorof Float) (Vectorof Float)))
(define pieces-measured
(for/list : (Listof (Vector Float Float Float)) ([p (in-vector pieces)])
(define wb (cast (quad-attr-ref p world:word-break-key #f) (U Quad False)))
(vector
;; throw in 0.0 in case for/list returns empty
(apply + 0.0 (for/list : (Listof Float) ([qli (in-list (quad-list p))])
(define q (cast qli Quad))
(define str (quad->string q))
(if (equal? str "")
(cast (quad-attr-ref q world:width-key 0.0) Float)
(apply measure-text (quad->string q) (font-attributes-with-defaults q)))))
(if wb (cast (apply measure-text (cast (quad-attr-ref wb world:no-break-key) String) (font-attributes-with-defaults wb)) Float) 0.0)
(if wb (cast (apply measure-text (cast (quad-attr-ref wb world:before-break-key) String) (font-attributes-with-defaults wb)) Float) 0.0))))
(values
(for/vector : (Vectorof Float) ([p (in-list pieces-measured)])
(fl+ (vector-ref p 0) (vector-ref p 1))) ; first = word length, second = nb length
(for/vector : (Vectorof Float) ([p (in-list pieces-measured)])
(fl+ (vector-ref p 0) (vector-ref p 2))))) ; first = word length, third = bb length
(define/typed (make-trial-line pieces-rendered-widths pieces-rendered-before-break-widths i j)
((Vectorof Float) (Vectorof Float) Nonnegative-Integer Nonnegative-Integer . -> . (Vectorof Float))
(let ([vec (vector-copy pieces-rendered-widths i j)])
(vector-set! vec (sub1 (vector-length vec)) (vector-ref pieces-rendered-before-break-widths (sub1 j)))
vec))
(define/typed (get-line-width line)
((Vectorof Float) . -> . Float)
(round-float (apply + (vector->list line))))
(struct $penalty ([hyphens : Nonnegative-Integer][width : Value-Type]) #:transparent #:mutable)
;; top-level adaptive wrap proc.
;; first-fit and best-fit are variants.
(define-type Find-Breakpoints-Type ((Vectorof Quad) Float . -> . (Listof Nonnegative-Integer)))
(define/typed (adaptive-fit-proc pieces measure [use-first? #t] [use-best? #t])
(((Vectorof Quad) Float) (Boolean Boolean) . ->* . (Listof Nonnegative-Integer))
;; this is the winning performance strategy: extract the numbers first, then just wrap on those.
;; todo: how to avoid re-measuring pieces later?
;; todo: how to retain information about words per line and hyphen at end?
(define-values (pieces-rendered-widths pieces-rendered-before-break-widths)
(make-piece-vectors pieces))
(define pieces-with-word-space ((inst vector-map Boolean Quad) (λ(piece) (and (quad-has-attr? piece world:word-break-key) (equal? (quad-attr-ref (cast (quad-attr-ref piece world:word-break-key) Quad) 'nb) " "))) pieces))
(define (make-first-fit-bps-and-widths)
(define-values (folded-bps folded-widths)
(for/fold ([bps : (Listof Nonnegative-Integer) '(0)][line-widths : (Listof Float) empty])([j-1 (in-range (vector-length pieces))])
(define line-width (get-line-width (make-trial-line pieces-rendered-widths
pieces-rendered-before-break-widths
(car bps) (cast (add1 j-1) Nonnegative-Integer))))
(if (fl> line-width (fl* world:allowed-overfull-ratio measure))
(values (cons (cast j-1 Nonnegative-Integer) bps) (cons line-width line-widths))
(values bps line-widths))))
(values (cdr (reverse folded-bps)) (reverse folded-widths)))
(define (fu-formula)
(define line-count (length trial-line-widths))
(cond
[(<= line-count 2) 1.0] ; signals that first-fit is always OK with 1 or 2 lines
[else ; only measure middle lines. we know bps has at least 2 bps
(define looseness-stddev (stddev ((inst map Float Float) (λ(x) (calc-looseness x measure)) (drop-right (drop trial-line-widths 1) 1))))
(define piece-count (vector-length pieces-rendered-widths))
(define pieces-per-line (fl/ (fl piece-count) (sub1 (fl line-count)))) ; todo: more accurate to count only pieces in middle
(apply + (list 2.2 (fllog (flabs (cast looseness-stddev Float))) (* 0.09 pieces-per-line)))])) ; the FU FORMULA
;; only buy first-fit-bps if use-first? is true.
;; use (values '(0) '(0.0)) as void-ish values that will typecheck properly.
(define-values (first-fit-bps trial-line-widths) (if use-first? (make-first-fit-bps-and-widths) (values '(0) '(0.0))))
(cond
;; possible outcomes at this branch:
;; adaptive wrap: use-first and use-best are true, so first-fit-bps will exist, and fu-formula will be used.
;; first-fit wrap: use-first is true but not use-best. So first-fit-bps will be returned regardless.
;; best-fit wrap: use-first is false but use-best is true. So first-fit-bps will be skipped, and move on to best-fit.
[(and use-first? (if use-best? (fl> (fu-formula) 0.0) #t))
(log-quad-debug "first-fit breakpoints = ~a" first-fit-bps)
first-fit-bps]
[else
(define/typed ($penalty->value x)
($penalty . -> . Value-Type)
($penalty-width x))
(define initial-value ($penalty 0 0.0))
(log-quad-debug "~a pieces to wrap = ~v" (vector-length pieces) (vector-map quad->string pieces))
(define/typed (penalty i j)
Matrix-Proc-Type
(cond
[(or (>= i j) ; implies negative or zero length line
(> j (vector-length pieces))) ; exceeds available pieces
($penalty 0 (fl* -1.0 (fl i)))] ; ocm out of bounds signal
[else
(define penalty-up-to-i (cast (ocm-min-entry ocm i) $penalty))
(define last-piece-to-test (vector-ref pieces (sub1 j)))
(define new-hyphen?
(and (quad-has-attr? last-piece-to-test world:word-break-key)
(equal? (cast (quad-attr-ref (cast (quad-attr-ref last-piece-to-test world:word-break-key) Quad) world:before-break-key) String) "-")))
(define cumulative-hyphens (if (not new-hyphen?)
0
(add1 ($penalty-hyphens penalty-up-to-i))))
($penalty
cumulative-hyphens
(round-float
(apply + (list
(if (> cumulative-hyphens world:hyphen-limit)
(fl world:hyphen-penalty)
0.0)
(fl world:new-line-penalty)
($penalty->value penalty-up-to-i)
(let ([line-width (get-line-width (make-trial-line pieces-rendered-widths pieces-rendered-before-break-widths i j))])
(cond
;; overfull line: huge penalty prevents break; multiplier is essential for monotonicity.
;; multiply by -1 because line-width is longer than measure, thus diff is negative
[(fl> line-width (fl* world:allowed-overfull-ratio measure))
(fl* (fl- line-width measure) (flexpt 10.0 7.0))]
;; standard penalty, optionally also applied to last line (by changing operator)
[((if world:last-line-can-be-short < <=) j (vector-length pieces))
(define words (fl (vector-count (λ(x) x) (vector-copy pieces-with-word-space i (sub1 j)))))
(fl/ (flexpt (fl- measure line-width) 2.0) (flmax 1.0 words))]
;; only option left is (= j (vector-length pieces)), meaning we're on the last line.
;; 0 penalty means any length is ok.
;[(< (length pieces-to-test) (world:minimum-last-line-pieces)) 50000]
[else 0.0]))))))]))
(define ocm : OCM-Type (make-ocm penalty (cast $penalty->value Entry->Value-Type) initial-value))
;; starting from last position, ask ocm for position of row minimum (= new-pos)
;; collect this value, and use it as the input next time
;; until you reach first position.
(define first-position 0)
(define last-position (vector-length pieces))
(define result (let loop : (Listof Nonnegative-Integer) ([pos : Nonnegative-Integer last-position][acc : (Listof Nonnegative-Integer) null])
(let ([next-pos (cast (ocm-min-index ocm pos) Nonnegative-Integer)]) ; first look ahead ...
(if (= next-pos first-position) ; therefore we're done
acc
(loop next-pos (cons next-pos acc))))))
(log-quad-debug "best-fit breakpoints = ~a" result)
result]))
;; wrap proc based on greedy proc
(define-syntax-rule (define+provide name expr ...)
(begin
(provide name)
(define name expr ...)))
(define+provide wrap-first (make-wrap-proc
make-pieces
quad-width
pieces->line
(λ(x y) (adaptive-fit-proc (cast x (Vectorof Quad)) (cast y Float) #t #f))))
;; wrap proc based on penalty function
(define+provide wrap-best (make-wrap-proc
make-pieces
quad-width
pieces->line
(λ(x y) (adaptive-fit-proc (cast x (Vectorof Quad)) (cast y Float) #f #t)))) ; note difference in boolean args
(define+provide wrap-adaptive (make-wrap-proc
make-pieces
quad-width
pieces->line
adaptive-fit-proc))
(define/typed (fixed-width? q)
(Quad . -> . Boolean)
(quad-has-attr? q world:width-key))
;; build quad out to a given width by distributing excess into spacers
;; todo: adjust this to work recursively, so that fill operation cascades down
(define/typed+provide (fill starting-quad [target-width? #f])
((Quad) ((Option Float)) . ->* . Quad)
(define target-width (fl (or target-width? (cast (quad-attr-ref starting-quad world:measure-key) Float))))
(define subquads (cast (quad-list starting-quad) (Listof Quad)))
(define-values (flexible-subquads fixed-subquads) (partition spacer? subquads)) ; only puts fill into spacers.
(define width-used (apply + ((inst map Float Quad) quad-width fixed-subquads)))
(define width-remaining (round-float (- target-width width-used)))
(cond
;; check for zero condition because we want to divide by this number
;; if there's no spacers, put one in
;; todo: go in two rounds, once for word spacers, and once for line spacers?
;; or separate the line alignment & word-spacing properties?
[(fl= 0.0 (fl (length flexible-subquads))) (fill (insert-spacers-in-line starting-quad (world:horiz-alignment-default)) target-width)]
[else (define width-per-flexible-quad (round-float (fl/ width-remaining (fl (length flexible-subquads)))))
(define new-quad-list ((inst map Quad Quad) (λ(q) (if (spacer? q)
(quad-attr-set q world:width-key width-per-flexible-quad)
q)) subquads))
(quad (quad-name starting-quad) (quad-attrs (quad-attr-set starting-quad world:width-key target-width)) new-quad-list)]))
;; add x positions to a list of fixed-width quads
;; todo: adjust this to work recursively, so that positioning operation cascades down
(define/typed+provide (add-horiz-positions starting-quad)
(Quad . -> . Quad)
(define-values (new-quads final-width)
(for/fold ([new-quads : (Listof Quad) empty][width-so-far : Float 0.0])([qi (in-list (quad-list starting-quad))])
(define q (cast qi Quad))
(values (cons (quad-attr-set q world:x-position-key width-so-far) new-quads) (round-float (fl+ (quad-width q) width-so-far)))))
(quad (quad-name starting-quad) (quad-attrs starting-quad) (reverse new-quads)))