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101 lines
4.8 KiB
Racket
101 lines
4.8 KiB
Racket
#lang typed/racket/base
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(require (for-syntax typed/racket/base ))
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(require typed/racket/class math/flonum racket/list racket/file)
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(require/typed racket/draw
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[record-dc% (Class (init-field)
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(get-text-extent (String (Instance (Class (init-field))) Any . -> . (values Nonnegative-Real Nonnegative-Real Nonnegative-Real Nonnegative-Real))))]
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[make-font ((#:size Nonnegative-Float) (#:style Symbol) (#:weight Symbol) (#:face String) . -> . (Instance (Class (init-field))))])
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(require/typed sugar/cache [make-caching-proc (Procedure . -> . Procedure)])
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(require/typed racket/serialize [serialize (Any . -> . Any)]
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[deserialize (Any . -> . (HashTable Any Any))])
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(provide measure-text measure-ascent round-float update-text-cache-file load-text-cache-file make-font/caching)
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(define precision 4.0)
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(define base (flexpt 10.0 precision))
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(define-syntax-rule (round-float x)
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(fl/ (flround (fl* base (fl x))) base))
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(define-syntax (values->list stx)
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(syntax-case stx ()
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[(_ values-expr) #'(call-with-values (λ () values-expr) list)]))
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(define dc (new record-dc%))
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(define max-size 1024.0) ; use fixnum to trigger faster bitshift division
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;; changing max-size invalidates font cache (because it's based on max size, duh)
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(define make-font/caching
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(make-caching-proc (λ (font weight style)
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(make-font #:size max-size #:style style #:weight weight #:face font))))
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(define (get-cache-file-path)
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(build-path "font.cache"))
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(define current-text-cache (make-parameter (make-hash '())))
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(define current-text-cache-changed? (make-parameter #f))
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(define current-font-cache (make-parameter (make-hash '())))
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(define (update-text-cache-file)
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(when (current-text-cache-changed?)
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(write-to-file (serialize (current-text-cache)) (get-cache-file-path) #:exists 'replace)
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(current-text-cache-changed? #f)))
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(define (load-text-cache-file)
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(define cache-file-path (get-cache-file-path))
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(current-text-cache (if (file-exists? cache-file-path)
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(deserialize (file->value cache-file-path))
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(make-hash '()))))
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(define-type Measurement-Result-Type (List Nonnegative-Real Nonnegative-Real Nonnegative-Real Nonnegative-Real))
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(define-type MMS-Type ((String String) (Symbol Symbol) . ->* . Measurement-Result-Type))
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(: measure-max-size-base MMS-Type)
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(define (measure-max-size-base text font [weight 'normal] [style 'normal])
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(define font-instance (cast (hash-ref! (current-font-cache) (list font weight style) (λ() (make-font #:size max-size #:style style #:weight weight #:face font))) (Instance (Class (init-field)))))
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;; 'combine' boolean only makes a difference for two or more chars
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(send dc get-text-extent text font-instance (>= (string-length text) 1))
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(cast (hash-ref! (current-text-cache) (list text font weight style) (λ() #;(current-text-cache-changed? #t)
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(values->list (send dc get-text-extent text font-instance (>= (string-length text) 1))))) Measurement-Result-Type))
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(define measure-cache ((inst make-hash (List String String Symbol Symbol) Measurement-Result-Type)))
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(: measure-max-size MMS-Type)
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(define (measure-max-size text font [weight 'normal] [style 'normal])
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(hash-ref! measure-cache (list text font weight style) (λ () (measure-max-size-base text font weight style))))
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(define-syntax-rule (width x) (first x))
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(define-syntax-rule (height x) (second x))
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(define-syntax-rule (descent x) (third x))
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(define-syntax-rule (extra x) (fourth x))
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(define-syntax-rule (measure-text-max-size text font weight style)
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(width (measure-max-size text font weight style)))
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(: measure-text ((String Nonnegative-Float String) (Symbol Symbol) . ->* . Nonnegative-Float))
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(define (measure-text text size font [weight 'normal] [style 'normal])
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;; Native function only accepts integers, so get max-size and scale down to size needed.
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(define raw-measure (measure-text-max-size text font weight style))
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(cast (round-float (/ (* (exact->inexact raw-measure) (exact->inexact size)) max-size)) Nonnegative-Float))
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(define-syntax-rule (measure-ascent-max-size text font weight style)
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(let ([result-list (measure-max-size text font weight style)])
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(- (height result-list) (descent result-list))))
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(: measure-ascent ((String Nonnegative-Float String) (Symbol Symbol) . ->* . Nonnegative-Float))
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(define (measure-ascent text size font [weight 'normal] [style 'normal])
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; ((string? flonum? string?) (symbol? symbol?) . ->* . flonum?)
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;; Native function only accepts integers, so get max-size and scale down to size needed.
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(define raw-baseline-distance (measure-ascent-max-size text font weight style))
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(cast (round-float (/ (* (exact->inexact raw-baseline-distance) (exact->inexact size)) max-size)) Nonnegative-Float)) |