Eggs Unlimited - freetype

Note: This is taken from the Chicken Wiki, where a more recent version could be available.

freetype bindings for Chicken.

Usage

(use freetype)
(define lib (ft-init-freetype))
(define face
  (ft-new-face lib "/usr/share/fonts/truetype/msttcorefonts/arial.ttf"))
(ft-set-char-size face 0 (* 16 64) 300 300)
(ft-set-pixel-sizes face 0 16)
(define AV (make-ft-vector))
(ft-get-kerning face
                (ft-get-char-index face (char->integer #\A))
                (ft-get-char-index face (char->integer #\V))
                FT_KERNING_DEFAULT
                AV)
(print "AV kerning: " (ft-vector-x AV) " " (ft-vector-y AV))

 AV kerning: -64 0

Procedures

procedure: (ft-init-freetype) => <error-code>

Create a new freetype library object.

procedure: (ft-new-face <lib> <path>) => <face>

Load a font face from a file. Returns #f if the file can't be loaded.

procedure: (ft-set-char-size <face> <char-width> <char-height> <hres> <vres>) => <error-code>

procedure: (ft-set-pixel-size <face> <pixel-width> <pixel-height>) => <error-code>

procedure: (ft-get-char-index <face> <char-code>) => <glyph-index>

procedure: (ft-load-glyph <face> <glyph-index> <load-flags>) => <error-code>

procedure: (ft-load-char <face> <char-code> <load-flags>) => <error-code>

procedure: (ft-render-glyph <glyph> <render-flags>) => <error-code>

procedure: (ft-get-kerning <face> <left> <right> <kerning-mode> <vector>) => <error-code>

procedure: (ft-select-charmap <face> <charmap-index>) => <error-code>

procedure: (ft-set-transform <face> <matrix> <delta>)

Records

ft-vector

make-ft-vector
free-ft-vector
ft-vector-x
ft-vector-y
ft-vector-x-set!
ft-vector-y-set!

ft-matrix

make-ft-matrix
free-ft-matrix
ft-matrix-xx
ft-matrix-xy
ft-matrix-yx
ft-matrix-yy
ft-matrix-xx-set!
ft-matrix-xy-set!
ft-matrix-yx-set!
ft-matrix-yy-set!

ft-face

free-ft-face
ft-face-num-faces
ft-face-face-index
ft-face-face-flags
ft-face-style-flags
ft-face-num-glyphs
ft-face-family-name
ft-face-style-name
ft-face-num-fixed-sizes
ft-face-available-sizes
ft-face-num-charmaps
ft-face-charmaps
ft-face-generic-data
ft-face-generic-finalizer
ft-face-bbox-xmin
ft-face-bbox-xmax
ft-face-bbox-ymin
ft-face-bbox-ymax
ft-face-units-per-EM
ft-face-ascender
ft-face-descender
ft-face-height
ft-face-max-advance-width
ft-face-max-advance-height
ft-face-underline-position
ft-face-underline-thickness
ft-face-glyph
ft-face-size
ft-face-charmap

ft-glyph-slot

free-ft-glyph-slot
ft-glyph-slot-library
ft-glyph-slot-face
ft-glyph-slot-next
ft-glyph-slot-reserved
ft-glyph-slot-generic-data
ft-glyph-slot-generic-finalizer
ft-glyph-slot-metrics
ft-glyph-slot-linear-hori-advance
ft-glyph-slot-linear-vert-advance
ft-glyph-slot-advance-x
ft-glyph-slot-advance-y
ft-glyph-slot-format
ft-glyph-slot-bitmap
ft-glyph-slot-outline
ft-glyph-slot-num_subglyphs
ft-glyph-slot-subglyphs
ft-glyph-slot-control-data
ft-glyph-slot-control-len
ft-glyph-slot-lsb-delta
ft-glyph-slot-rsb-delta

ft-bitmap

free-ft-bitmap
ft-bitmap-rows
ft-bitmap-width
ft-bitmap-pitch
ft-bitmap-buffer
ft-bitmap-num-grays
ft-bitmap-pixel-mode
ft-bitmap-palette-mode
ft-bitmap-palette

ft-glyph-metrics

free-ft-glyph-metrics
ft-glyph-metrics-width
ft-glyph-metrics-height
ft-glyph-metrics-hori-bearing-x
ft-glyph-metrics-hori-bearing-y
ft-glyph-metrics-hori-advance
ft-glyph-metrics-vert-bearing-x
ft-glyph-metrics-vert-bearing-y
ft-glyph-metrics-vert-advance

Enums

Encodings

FT_ENCODING_NONE
FT_ENCODING_MS_SYMBOL
FT_ENCODING_UNICODE
FT_ENCODING_SJIS
FT_ENCODING_GB2312
FT_ENCODING_BIG5
FT_ENCODING_WANSUNG
FT_ENCODING_JOHAB
FT_ENCODING_ADOBE_STANDARD
FT_ENCODING_ADOBE_EXPERT
FT_ENCODING_ADOBE_CUSTOM
FT_ENCODING_ADOBE_LATIN_1
FT_ENCODING_OLD_LATIN_2
FT_ENCODING_APPLE_ROMAN

Face Flags

FT_FACE_FLAG_SCALABLE
FT_FACE_FLAG_FIXED_SIZES
FT_FACE_FLAG_FIXED_WIDTH
FT_FACE_FLAG_SFNT
FT_FACE_FLAG_HORIZONTAL
FT_FACE_FLAG_VERTICAL
FT_FACE_FLAG_KERNING
FT_FACE_FLAG_FAST_GLYPHS
FT_FACE_FLAG_MULTIPLE_MASTERS
FT_FACE_FLAG_GLYPH_NAMES
FT_FACE_FLAG_EXTERNAL_STREAM

Style Flags

FT_STYLE_FLAG_ITALIC
FT_STYLE_FLAG_BOLD

Open Flags

FT_OPEN_MEMORY
FT_OPEN_STREAM
FT_OPEN_PATHNAME
FT_OPEN_DRIVER
FT_OPEN_PARAMS

Load Options

FT_LOAD_DEFAULT
FT_LOAD_NO_SCALE
FT_LOAD_NO_HINTING
FT_LOAD_RENDER
FT_LOAD_NO_BITMAP
FT_LOAD_VERTICAL_LAYOUT
FT_LOAD_FORCE_AUTOHINT
FT_LOAD_CROP_BITMAP
FT_LOAD_PEDANTIC
FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH
FT_LOAD_NO_RECURSE
FT_LOAD_IGNORE_TRANSFORM
FT_LOAD_MONOCHROME
FT_LOAD_LINEAR_DESIGN
FT_LOAD_TARGET_NORMAL
FT_LOAD_TARGET_LIGHT
FT_LOAD_TARGET_MONO
FT_LOAD_TARGET_LCD
FT_LOAD_TARGET_LCD_V

Render Mode

FT_RENDER_MODE_NORMAL
FT_RENDER_MODE_LIGHT
FT_RENDER_MODE_MONO
FT_RENDER_MODE_LCD
FT_RENDER_MODE_LCD_V
FT_RENDER_MODE_MAX

Kerning Mode

FT_KERNING_DEFAULT
FT_KERNING_UNFITTED
FT_KERNING_UNSCALED

Example

;; Render an anti-aliased "A" to text using the chars 0-9 for grayscale.

(use freetype lolevel)

(define lib (ft-init-freetype))
(define face
  (ft-new-face lib "/usr/share/fonts/truetype/msttcorefonts/arial.ttf"))
(ft-set-char-size face 0 (* 16 64) 300 300)
(ft-set-pixel-sizes face 0 16)

(ft-load-char face (char->integer #\A) FT_LOAD_DEFAULT)
(ft-render-glyph (ft-face-glyph face) FT_RENDER_MODE_NORMAL)

(let* ((glyph (ft-face-glyph face))
       (bitmap (ft-glyph-slot-bitmap glyph))
       (width (ft-bitmap-width bitmap))
       (rows (ft-bitmap-rows bitmap))
       (buf (ft-bitmap-buffer bitmap)))
  (do ((i 0 (+ i 1)))
      ((= i rows))
    (do ((j 0 (+ j 1)))
        ((= j width))
      (let ((d (pointer-u8-ref
                   (pointer-offset buf (+ j (* i width))))))
        (write-char (if (zero? d)
                        #\space
                        (integer->char
                         (+ (inexact->exact (truncate (/ d 25.6)))
                            (char->integer #\0)))))))
    (newline)))

     393    
     666    
    09190   
    37 73   
    63 36   
   090 090  
   27   72  
   6999996  
  090   090 
  26     72 
  63     36 
 080     080

Author

Alex Shinn

License

BSD

History

0.1: initial release