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#lang pitfall/racket
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(require "freetype-ffi.rkt")
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(provide Glyph CFFGlyph TTFGlyph)
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(module+ test (require rackunit))
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#|
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/**
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* Glyph objects represent a glyph in the font. They have various properties for accessing metrics and
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* the actual vector path the glyph represents, and methods for rendering the glyph to a graphics context.
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*
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* You do not create glyph objects directly. They are created by various methods on the font object.
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* There are several subclasses of the base Glyph class internally that may be returned depending
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* on the font format, but they all inherit from this class.
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*/
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|#
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;; approximates
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;; https://github.com/devongovett/fontkit/blob/master/src/glyph/Glyph.js
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(define (is-mark? codepoint)
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;; mark classes = Mn Me Mc
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(regexp-match #px"\\p{Mn}|\\p{Me}|\\p{Mc}" (string (integer->char codepoint))))
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(module+ test
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(check-true (and (is-mark? #x300) #t))
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(check-false (and (is-mark? #x2ee) #t)))
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(define-subclass object% (Glyph id codePoints font)
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(field [_font font]
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[isMark (andmap is-mark? codePoints)]
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[isLigature (> (length codePoints) 1)]
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[_metrics #f])
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(as-methods
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advanceWidth
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_getMetrics))
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(define/contract (advanceWidth this)
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(->m number?)
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(hash-ref (_getMetrics this) 'advanceWidth))
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(define/contract (_getMetrics this)
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(->m hash?)
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(unless (· this _metrics)
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(define face (· this _font ft-face))
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(FT_Load_Glyph face (· this id) FT_LOAD_NO_RECURSE)
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(define glyph (FT_FaceRec-glyph face))
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(define glyph-metrics (FT_GlyphSlotRec-metrics glyph))
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(set-field! _metrics this (mhash))
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(hash-set*! (· this _metrics)
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'advanceWidth (FT_Glyph_Metrics-horiAdvance glyph-metrics)
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'leftBearing (FT_Glyph_Metrics-horiBearingX glyph-metrics)))
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(· this _metrics))
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(define-subclass Glyph (CFFGlyph)
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(error 'cff-glyph-unimplemented))
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(define-subclass Glyph (TTFGlyph)
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) |