wiser division

main
Matthew Butterick 5 years ago
parent 8eb6450296
commit 97a18d4fb4

@ -17,7 +17,7 @@
(define mdash "") (define mdash "")
(define-tag-function (p attrs exprs) (define-tag-function (p attrs exprs)
(qexpr (append `((keep-first "2")(keep-last "2")(display ,(symbol->string (gensym)))) attrs) exprs)) (qexpr (append `((keep-first "2")(keep-last "3")(display ,(symbol->string (gensym)))) attrs) exprs))
(define-tag-function (hr attrs exprs) (define-tag-function (hr attrs exprs)
hrbr) hrbr)
@ -307,31 +307,30 @@
(define (make-nobreak! q) (quad-set! q 'no-pbr "true")) (define (make-nobreak! q) (quad-set! q 'no-pbr "true"))
(define (finish-keep-with-next! reversed-lines) (define (do-keep-with-next! reversed-lines)
;; paints nobreak onto spacers that follow keep-with-next lines ;; paints nobreak onto spacers that follow keep-with-next lines
;; (we are iterating backward, so the geometrically previous ln follows the spacer) ;; (we are iterating backward, so the geometrically previous ln follows the spacer)
(for ([this-ln (in-list reversed-lines)] (for ([this-ln (in-list reversed-lines)]
[prev-ln (in-list (cdr reversed-lines))] [prev-ln (in-list (cdr reversed-lines))]
#:when (and (line-spacer? this-ln) #:when (and (line-spacer? this-ln)
(quad-ref prev-ln 'keep-with-next))) (quad-ref prev-ln 'keep-with-next)))
(make-nobreak! prev-ln)
(make-nobreak! this-ln))) (make-nobreak! this-ln)))
(define (apply-keeps lines) (define (apply-keeps lines)
(define groups-of-lines (contiguous-group-by (λ (x) (quad-ref x 'display)) lines)) (define groups-of-lines (contiguous-group-by (λ (x) (quad-ref x 'display)) lines))
(for*/fold ([reversed-lines null] (for*/fold ([reversed-lines null]
#:result (begin #:result (begin
(finish-keep-with-next! reversed-lines) (do-keep-with-next! reversed-lines)
(reverse reversed-lines))) (reverse reversed-lines)))
([group (in-list groups-of-lines)] ([group (in-list groups-of-lines)]
[group-len (in-value (length group))] [group-len (in-value (length group))]
[(ln idx0) (in-indexed group)]) [(ln idx0) (in-indexed group)])
(define idx (add1 idx0)) (define idx (add1 idx0))
(cond
;; always catch last line of block in this case ;; always catch last line of block in this case
;; so later cases are guaranteed to have earlier lines. ;; so later cases are guaranteed to have earlier lines.
[(= idx group-len) (unless (= idx group-len)
(when (quad-ref ln 'keep-with-next) (cond
(make-nobreak! ln))]
;; if we have 'keep-all we can skip 'keep-first and 'keep-last cases ;; if we have 'keep-all we can skip 'keep-first and 'keep-last cases
[(quad-ref ln 'keep-all) (make-nobreak! ln)] [(quad-ref ln 'keep-all) (make-nobreak! ln)]
;; to keep n lines, we only paint the first n - 1 ;; to keep n lines, we only paint the first n - 1
@ -341,7 +340,7 @@
(make-nobreak! ln)] (make-nobreak! ln)]
[(let ([keep-last (quad-ref ln 'keep-last)]) [(let ([keep-last (quad-ref ln 'keep-last)])
(and (number? keep-last) (< (- group-len keep-last) idx))) (and (number? keep-last) (< (- group-len keep-last) idx)))
(make-nobreak! ln)]) (make-nobreak! ln)]))
(cons ln reversed-lines))) (cons ln reversed-lines)))
(define zoom-mode? #f) (define zoom-mode? #f)

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