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typesetting/quad2/layout.rkt

51 lines
1.8 KiB
Racket

#lang debug racket/base
(require racket/contract
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"pipeline.rkt"
"quad.rkt")
(provide layout)
(define/contract (posn-add p0 p1)
($point? $size? . -> . $point?)
($point (+ ($point-x p0) ($size-width p1)) (+ ($point-y p0) ($size-height p1))))
(define/contract (size char)
(quad? . -> . $size?)
($size 1 1))
(define/contract (advance char)
(quad? . -> . $size?)
($size 1 0))
(define (min-x rect) ($point-x ($rect-origin rect)))
(define (width rect) ($size-width ($rect-size rect)))
(define (max-x rect) (+ (min-x rect) (width rect)))
(define (min-y rect) ($point-y ($rect-origin rect)))
(define (height rect) ($size-height ($rect-size rect)))
(define (max-y rect) (+ (min-y rect) (height rect)))
(define/contract (rect-contains-point? rect pt)
($rect? $point? . -> . boolean?)
(and (<= (min-x rect) ($point-x pt) (max-x rect))
(<= (min-y rect) ($point-y pt) (max-y rect))))
(define/contract (rect-contains-rect? outer inner)
($rect? $rect? . -> . boolean?)
(and (rect-contains-point? outer ($rect-origin inner))
(rect-contains-point? outer ($point (max-x inner) (max-y inner)))))
(define-pass (layout qs)
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#:pre (list-of has-no-position?)
#:post (list-of has-position?)
(define frame ($rect ($point 0 0) ($size (current-wrap-width) 30)))
(define (quad-fits? q posn)
(define q-size (size q))
(define quad-rect ($rect posn q-size))
(and (rect-contains-rect? frame quad-rect) posn))
(for/fold ([posn ($point 0 0)]
#:result qs)
([q (in-list qs)])
(define first-posn-on-next-line ($point 0 (add1 ($point-y posn))))
(define winning-posn (or (ormap (λ (posn) (quad-fits? q posn)) (list posn first-posn-on-next-line)) (error 'no-posn-that-fits)))
(set-quad-posn! q winning-posn)
(posn-add winning-posn (advance q))))