You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
50 lines
1.9 KiB
Racket
50 lines
1.9 KiB
Racket
#lang debug racket/base
|
|
(require racket/match)
|
|
(provide (all-defined-out))
|
|
|
|
;; TODO: define :font-size properly
|
|
(define :font-size 'font-size)
|
|
|
|
(define (pica->pts prefix [suffix #false])
|
|
;; both pieces of measurement are either positive or negative
|
|
((if (negative? prefix) - +) (+ (* (abs prefix) 12) (or suffix 0))))
|
|
(define (cm->in x) (/ x 2.54))
|
|
(define (in->pts x) (* 72 x))
|
|
(define (mm->cm x) (/ x 10.0))
|
|
|
|
(define (parse-dimension x [em-resolution-attrs #false])
|
|
(define pica-pat (regexp "^(p|pica)(s)?$"))
|
|
(define (unit->converter-proc unit)
|
|
(match unit
|
|
[(regexp #rx"^(pt|point)(s)?$") values] ; points
|
|
[(regexp pica-pat) pica->pts] ; pica (no pts)
|
|
[(regexp #rx"^inch(es)?|in(s)?$") in->pts] ; inches
|
|
[(regexp #rx"^cm(s)?$") (compose1 in->pts cm->in)] ; cm
|
|
[(regexp #rx"^mm(s)?$") (compose1 in->pts cm->in mm->cm)] ; mm
|
|
[(regexp #rx"^em(s)?$")
|
|
#:when em-resolution-attrs
|
|
;; if we don't have attrs for resolving the em string, we ignore it
|
|
(λ (num) (* (hash-ref em-resolution-attrs :font-size) num))]
|
|
[_ #false]))
|
|
(define parsed-thing
|
|
(match x
|
|
[#false #false]
|
|
[(? number? num) num]
|
|
[(? string? str)
|
|
(match (regexp-match #px"^(-?[0-9\\.]+)\\s*([a-z]+)([0-9\\.]+)?$" (string-downcase str))
|
|
[(list str
|
|
(app string->number num)
|
|
(app unit->converter-proc converter-proc)
|
|
#false) ; prefix measurement (suffix is #false)
|
|
#:when (and converter-proc num)
|
|
(converter-proc num)]
|
|
[(list str
|
|
(app string->number prefix-num)
|
|
(and (regexp pica-pat) unit)
|
|
(app string->number suffix-num))
|
|
#:when (and prefix-num suffix-num) ; prefix + suffix measurement (only pica + point)
|
|
(pica->pts prefix-num suffix-num)]
|
|
[_ str])]))
|
|
(match parsed-thing
|
|
[(and (? integer?) (? inexact?)) (inexact->exact parsed-thing)]
|
|
[_ parsed-thing])) |