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.
32 lines
1.1 KiB
Racket
32 lines
1.1 KiB
Racket
#lang br
|
|
(require "freetype-ffi.rkt")
|
|
(provide (all-defined-out))
|
|
|
|
(define ft-library (FT_Init_FreeType))
|
|
(define ft-face-cache (make-hash))
|
|
|
|
(define (font-pathstring->ft-face font-pathstring)
|
|
(hash-ref! ft-face-cache font-pathstring
|
|
(λ ()
|
|
(unless (file-exists? font-pathstring)
|
|
(error 'measure-char (format "font path ~v does not exist" font-pathstring)))
|
|
(FT_New_Face ft-library font-pathstring 0))))
|
|
|
|
(define (get-glyph-idx font-pathstring char)
|
|
(FT_Get_Char_Index (font-pathstring->ft-face font-pathstring) (char->integer char)))
|
|
|
|
(define (measure-char font-pathstring char)
|
|
(measure-char-idx font-pathstring (get-glyph-idx font-pathstring char)))
|
|
|
|
(define (measure-char-idx font-pathstring glyph-idx)
|
|
(define ft-face (font-pathstring->ft-face font-pathstring))
|
|
(FT_Load_Glyph ft-face glyph-idx FT_LOAD_NO_RECURSE) ; loads into FTFace's 'glyph' slot
|
|
(define width (FT_Vector-x (FT_GlyphSlotRec-advance (FT_FaceRec-glyph ft-face))))
|
|
width)
|
|
|
|
|
|
(module+ test
|
|
(require rackunit)
|
|
(check-equal? (measure-char "miso.otf" #\f) 296)
|
|
(check-equal? (measure-char-idx "miso.otf" 46) 296))
|