freetype.h

a very goog book

  /*                           positive, expressed in font units.  The     */
  /*                           value can be computed as                    */
  /*                           `ascender+descender+line_gap' where the     */
  /*                           value of `line_gap' is also called          */
  /*                           `external leading'.  Only relevant for      */
  /*                           scalable formats.                           */
  /*                                                                       */
  /*    max_advance_width   :: The maximal advance width, in font units,   */
  /*                           for all glyphs in this face.  This can be   */
  /*                           used to make word wrapping computations     */
  /*                           faster.  Only relevant for scalable         */
  /*                           formats.                                    */
  /*                                                                       */
  /*    max_advance_height  :: The maximal advance height, in font units,  */
  /*                           for all glyphs in this face.  This is only  */
  /*                           relevant for vertical layouts, and should   */
  /*                           be set to the `height' for fonts that do    */
  /*                           not provide vertical metrics.  Only         */
  /*                           relevant for scalable formats.              */
  /*                                                                       */
  /*    underline_position  :: The position, in font units, of the         */
  /*                           underline line for this face.  It's the     */
  /*                           center of the underlining stem.  Only       */
  /*                           relevant for scalable formats.              */
  /*                                                                       */
  /*    underline_thickness :: The thickness, in font units, of the        */
  /*                           underline for this face.  Only relevant for */
  /*                           scalable formats.                           */
  /*                                                                       */
  /*    glyph               :: The face's associated glyph slot(s).  This  */
  /*                           object is created automatically with a new  */
  /*                           face object.  However, certain kinds of     */
  /*                           applications (mainly tools like converters) */
  /*                           can need more than one slot to ease their   */
  /*                           task.                                       */
  /*                                                                       */
  /*    size                :: the current active size for this face       */
  /*                                                                       */
  /*    charmap             :: the current active charmap for this face    */
  /*                                                                       */
  typedef struct  FT_FaceRec_
  {
    FT_Long           num_faces;
    FT_Long           face_index;

    FT_Long           face_flags;
    FT_Long           style_flags;

    FT_Long           num_glyphs;

    FT_String*        family_name;
    FT_String*        style_name;

    FT_Int            num_fixed_sizes;
    FT_Bitmap_Size*   available_sizes;

    FT_Int            num_charmaps;
    FT_CharMap*       charmaps;

    FT_Generic        generic;

    /*# the following are only relevant to scalable outlines */
    FT_BBox           bbox;

    FT_UShort         units_per_EM;
    FT_Short          ascender;
    FT_Short          descender;
    FT_Short          height;

    FT_Short          max_advance_width;
    FT_Short          max_advance_height;

    FT_Short          underline_position;
    FT_Short          underline_thickness;

    FT_GlyphSlot      glyph;
    FT_Size           size;
    FT_CharMap        charmap;

    /*@private begin */

    FT_Driver         driver;
    FT_Memory         memory;
    FT_Stream         stream;

    FT_ListRec        sizes_list;

    FT_Generic        autohint;
    void*             extensions;

    FT_Face_Internal  internal;

    /*@private end */

  } FT_FaceRec;


  /*************************************************************************/
  /*                                                                       */
  /* <Constant>                                                            */
  /*    FT_FACE_FLAG_SCALABLE                                              */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A bit-field constant, used to indicate that a given face provides  */
  /*    vectorial outlines (i.e., TrueType or Type1).  This doesn't        */
  /*    prevent embedding of bitmap strikes though, i.e., a given face can */
  /*    have both this bit set, and a `num_fixed_sizes' property > 0.      */
  /*                                                                       */
#define FT_FACE_FLAG_SCALABLE  1


  /*************************************************************************/
  /*                                                                       */
  /* <Constant>                                                            */
  /*    FT_FACE_FLAG_FIXED_SIZES                                           */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A bit-field constant, used to indicate that a given face contains  */
  /*    `fixed sizes', i.e., bitmap strikes for some given pixel sizes.    */
  /*    See the `num_fixed_sizes' and `available_sizes' face properties    */
  /*    for more information.                                              */
  /*                                                                       */
#define FT_FACE_FLAG_FIXED_SIZES  2


  /*************************************************************************/
  /*                                                                       */
  /* <Constant>                                                            */
  /*    FT_FACE_FLAG_FIXED_WIDTH                                           */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A bit-field constant, used to indicate that a given face contains  */
  /*    fixed-width characters (like Courier, Lucida, MonoType, etc.).     */
  /*                                                                       */
#define FT_FACE_FLAG_FIXED_WIDTH  4


  /*************************************************************************/
  /*                                                                       */
  /* <Constant>                                                            */
  /*    FT_FACE_FLAG_SFNT                                                  */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A bit-field constant, used to indicate that a given face uses the  */
  /*    `sfnt' storage fomat.  For now, this means TrueType or OpenType.   */
  /*                                                                       */
#define FT_FACE_FLAG_SFNT  8


  /*************************************************************************/
  /*                                                                       */
  /* <Constant>                                                            */
  /*    FT_FACE_FLAG_HORIZONTAL                                            */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A bit-field constant, used to indicate that a given face contains  */
  /*    horizontal glyph metrics.  This should be set for all common       */
  /*    formats, but who knows.                                            */
  /*                                                                       */
#define FT_FACE_FLAG_HORIZONTAL  0x10


  /*************************************************************************/
  /*                                                                       */
  /* <Constant>                                                            */
  /*    FT_FACE_FLAG_VERTICAL                                              */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A bit-field constant, used to indicate that a given face contains  */
  /*    vertical glyph metrics.  If not set, the glyph loader will         */
  /*    synthetize vertical metrics itself to help display vertical text   */
  /*    correctly.                                                         */
  /*                                                                       */
#define FT_FACE_FLAG_VERTICAL  0x20


  /*************************************************************************/
  /*                                                                       */
  /* <Constant>                                                            */
  /*    FT_FACE_FLAG_KERNING                                               */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A bit-field constant, used to indicate that a given face contains  */
  /*    kerning information.  When set, this information can be retrieved  */
  /*    through the function @FT_Get_Kerning().  Note that when unset,     */
  /*    this function will always return the kerning vector (0,0).         */
  /*                                                                       */
#define FT_FACE_FLAG_KERNING  0x40


  /*************************************************************************/
  /*                                                                       */
  /* <Constant>                                                            */
  /*    FT_FACE_FLAG_FAST_GLYPHS                                           */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A bit-field constant, used to indicate that the glyphs in a given  */
  /*    font can be retrieved very quickly, and that a glyph cache is thus */
  /*    not necessary for any of its child size objects.                   */
  /*                                                                       */
  /*    This flag should really be set for fixed-size formats like FNT,    */
  /*    where each glyph bitmap is available directly in binary form       */
  /*    without any kind of compression.                                   */
  /*                                                                       */
  /* <Note>                                                                */
  /*    This bit flag is deprecated, because even if the bitmaps are       */
  /*    available directly in the font file, the glyph sub-system is       */