			The FreeType Engine

                       Core Library Reference


                -----------------------------------


                         Table of Contents:

                            Introduction

                            I. Types

                           II. Functions

                          III. Error codes


                        --------------------


Introduction:

  This  reference  presents the  types,  functions  and error  codes
  defined in the high-level API header file "freetype.h".  Note that
  all symbols defined  in this file are prefixed  by "TT_", to avoid
  name conflicts with other packages at link time.

  Some of its  parts are also dedicated to  the extension that comes
  by default with this distribution of the library, which is kerning
  support.

----------------------------------------------------------------------------

I. Types:

  Here is  the list of  all the types  defined in the  core FreeType
  API.  Their exact definition can be found in the file "freetype.h"
  which should be included by every client application.


  TT_Bool

    Can be either TRUE or FALSE.

  ..................................................................

  TT_Fixed

    A  signed 16.16  fixed  float value  used  to specify  transform
    coefficients and other important data.

  ..................................................................

  TT_FWord

    A signed  16 bits value used  to express a  distance measured in
    the font's original EM units.  These are also called 'FUnits' in
    the TrueType specification.

  ..................................................................

  TT_UFWord

    Unsigned FWord.

  ..................................................................

  TT_String
  TT_Char
  TT_Byte

    These types represent various 8 bits integer types (for strings,
    signed, and unsigned values, respectively).

  ..................................................................

  TT_Short
  TT_UShort
  TT_Long
  TT_ULong

    These four  types are  aliases for 16  bits integer  (signed and
    unsigned) and 32 bits one (signed and unsigned).

  ..................................................................

  TT_F2Dot14

    A  2.14 fixed  float integer  used  for unary  vectors and  some
    scaling coefficients.  Their layout is:

      s :  1 -- sign bit
      m :  1 -- mantissa bit
      f : 14 -- unsigned fractional value

    where  's:m' is  the 2-bit  signed  integer value  to which  the
    always positive fractional part 'f' should be added.

  ..................................................................

  TT_F26Dot6

    The  26.6 fixed  float format  used to  define  fractional pixel
    coordinates.  Here, 1 unit = 1/64 pixel.

  ..................................................................

  TT_Pos

    This  type  is  used  to  store  point  coordinates,  either  in
    fractional  pixels (26.6 fixed  floats) or  in EM  units (simple
    integers).

    The meaning of  the value depends on the  context.  For example,
    all  distances  relative to  a  scaled  glyph  are expressed  in
    fractional pixels (including bearings, advances, etc).  However,
    the same distances are in notional font units when the glyph was
    loaded unscaled.

  ..................................................................

  TT_UnitVector

    A simple  structure used to  store a unit vector.   The vector's
    coordinates are expressed in fixed float format (2.14).

      struct
      {
        TT_F2Dot14  x;
        TT_F2Dot14  y;
      }

  ..................................................................

  TT_Vector

    A  simple  structure  used   to  store  a  single  vector.   Its
    coordinates are expressed in fixed float format (26.6).

      struct
      {
        TT_Pos  x;
        TT_Pos  y;
      }

  ..................................................................

  TT_Matrix

    A  simple structure  used to  store  a single  2x2 matrix.   Its
    coefficients are  expressed in  16.16 fixed float  format.  This
    matrix is  used to perform  linear transformations on  the glyph
    outline, such as slanting or rotation.

      struct
      {
        TT_Fixed  xx, xy;
        TT_Fixed  yx, yy;
      };

    The computation performed is:

      x' = xx * x  +  xy * y
      y' = yx * x  +  yy * y

  ..................................................................

  TT_BBox

    A  simple   type  to   hold  a  glyph's   bbox.   Used   by  the
    TT_Get_Outline_BBox() API.

      struct
      {
        TT_Pos  xMin, yMin;
        TT_Pos  xMax, yMax;
      }

  ..................................................................

  TT_Outline

    Outlines are now full-class citizens, with their own API.

    This   structure  is   used  to   describe  a   vectorial  glyph
    representation to the rasterizer.   It is made of several fields
    described below.  Note however that:

    ***** THIS  STRUCTURE  MAY  CHANGE   IN  THE  FUTURE.   We  thus
    ***** encourage you to use  the outlines APIs described below to
    ***** process   your   outlines,  i.e.    create/copy/translate/
    ***** transform them as well as rendering bitmaps and pixmaps.

    ***** THE STRUCTURE CHANGED BETWEEN 1.0 and 1.1!

    Now that you've been warned, the fields are:

    - An array of points:

      The  'n_points'  field  gives  the  number of  points  in  the
      outline,  while  their coordinates  are  found  in the  single
      vector array 'points'.  The  'flag' array holds for each point
      a flag indicating its type.

      Currently, only  the first bit  (bit 0, the  least significant
      bit) of each byte is  meaningful to the rasterizer.  When set,
      it indicates that the point  is _on_ the curve.  When not set,
      the point is  said to be _off_ the curve.   It's then a Bezier
      control point.

      For  more information  about point  states, read  the TrueType
      specification or the scan-line documentation "raster.txt".

    - An array of contours' end-point indexes:

      The 'n_contours' field gives the number of contours, while the
      'contours'  array holds  the  indexes of  each contour's  last
      point.  Note that the first contour always begin at point 0.

      Hence, contours[0]  holds the index  of the last point  of the
      first contour.   The second  contour starting at  point number
      'contours[0]+1' and ending a point number 'contours[1]'.

      ** IMPORTANT NOTE: **
      *********************

        The last table entry _must_  always give the total number of
        points used to draw the contours, i.e.:

          contours[n_contours-1] == n_points

        If  this value is  bigger than  'n_points' when  calling the
        scan-line converter,  the component will  immediately return
        an error (TT_Err_Too_Many_Points).  If the value is smaller,
        only the points contained  in the described contours will be
        used in the conversion process.

    - An owner field:

      This  flag  should  **NEVER**  be  changed by  the  user.   It
      indicates whether the pointer fields own the arrays they refer
      to (when the flag is set),  or if they simply alias them (flag
      unset).

    - A high precision flag:

      When  this boolean  is  set (i.e.   not  zero), the  scan-line
      converter  uses  a higher  precision  to  compute segment  and
      Bezier coordinates (more  precisely, it uses 1/1024 precision,
      instead of the normal 1/64).  This is of course slower but can
      be important for glyphs rendered at small sizes.

    - A second pass flag:

      When this  boolean is set, the scan-line  converter performs a
      second  sweep on  the bitmap/pixmap  detect  vertical drop-out
      controls.  Only horizontal drop-outs are detected in the first
      pass.  This  is slower, but  important for glyphs  rendered at
      small sizes.

    - A dropout mode:

      Used to specify the method to apply for drop-out control (also
      called 'continuity testing'  in other environments).  The mode
      value  must be  one  of  the values  defined  by the  TrueType
      specification.

      The recent  modes 4  and 5 introduced  in the  newest TrueType
      specification (Version 1.6) are fully supported.

      An invalid value (i.e., other than  0, 1, 2, 4, or 5) is taken
      as no dropout control (equivalent to mode 0).

    NOTE 1:

      The outline returned  by TT_Get_Glyph_Outline() only alias the
      data that is part of  a glyph container (see below).  However,
      it is  possible to create  and process your own  outlines with
      the newest  API functions TT_New_Outline(), TT_Done_Outline(),
      TT_Copy_Outline(), TT_Translate_Outline(), etc.

      TT_Done_Outline() will  only discard an outline's  array if it
      owns them.

    NOTE 2:

      The outlines created by TT_New_Outline() are _not_ released by
      the  engine  on  TT_Done_FreeType(),  they must  be  discarded
      explicitly by the user who has created them!

    NOTE 3:

      The   glyph   loader   sets   the   fields   'high_precision',
      'dropout_mode' and 'second_pass' automatically.

    NOTE 4:

      This structure was called TT_Glyph_Outline in beta versions of
      FreeType.

  ..................................................................

  TT_Glyph_Metrics

    A structure  used to return simple glyph  metrics.  These values
    are expressed in fractional  pixels (26.6 format) if scaling was
    active, and in FUnits otherwise.

    The main idea was to accomodate vertical text layouts by getting
    rid  of the  two explicit  "leftSideBearing"  and "advanceWidth"
    names.

    Though  the library  only processes  horizontal metrics  for the
    moment, the fields meaning vary with the text layout:

      bearingX: also  known as the "left side  bearing".  This value
                gives the horizontal  distance from the pen position
                to the glyph's bbox xmin.

      bearingY: also  known as the  "top side bearing", this  is the
                vertical distance  from the baseline  to the glyph's
                bbox ymax.

      struct
      {
        TT_BBox  bbox;  /* the glyph's bbox */

        TT_Pos   bearingX;  /* left-side bearing */
        TT_Pos   bearingY;  /* top-side bearing  */

        TT_Pos   advance;   /* advance width or height */
      };

    ** IMPORTANT NOTE **

      Because  of the convention  used by  the TrueType  engine, the
      outlines generated  at glyph-load time are all  placed so that
      the pen is at position  (0,0).  This means that you don't need
      to increase  the pen position by  "bearingX" and/or "bearingY"
      before  writing a glyph.   Text output  can be  performed with
      simple lines like:

        for (glyphs in text)
        {
          TT_Load_Glyph( ... );
          TT_Get_Glyph_Outline( glyph, &outline );
          TT_Translate_Outline( outline,
                                cur_pos_x * 64, cur_pos_y * 64 );

          TT_Get_Outline_Bitmap( outline, bitmap );
          /* blit bitmap to surface */

          cur_pos_x += (metrics.advance + 32) / 64
        }

      See the file 'test/ftstring.c' for concrete examples.

    NOTE 2:

      This structure has changed from the beta version of FreeType.

  ..................................................................

  TT_Big_Glyph_Metrics

    This structure,  though still unused,  will be used to  return a
    same glyph's metrics in both horizontal and vertical layouts.

      struct
      {
        TT_BBox  bbox;          /* the glyph's bbox */

        TT_Pos   horiBearingX;  /* horizontal left-side bearing */
        TT_Pos   horiBearingY;  /* horizontal top-side bearing  */

        TT_Pos   vertBearingX;  /* vertical left-side bearing */
        TT_Pos   vertBearingY;  /* vertical top-side bearing  */

        TT_Pos   horiAdvance;   /* horizontal advance */
        TT_Pos   vertAdvance;   /* vertical advance   */
      }

  ..................................................................

  TT_Instance_Metrics

    A structure used to return instance (point size) metrics.

      struct
      {
        int       pointSize;
        /* point size in points (1 point = 1/72 inch) */

        TT_UShort  x_ppem;  /* horizontal pixels per EM square */
        TT_UShort  y_ppem;  /* vertical pixels per EM square   */

        TT_Fixed   x_scale; /* 16.16 scale for EM -> frac pixels */
        TT_Fixed   y_scale; /* 16.16 scale for EM -> frac pixels */

        TT_UShort  x_resolution; /* device hor. res. in dpi  */
        TT_UShort  y_resolution; /* device vert. res. in dpi */
      };

    The fields  'x_scale' and  'y_scale' can be  used by  clients to
    convert from notional units to fractional pixels, e.g.:

      frac_distance = (em_distance * x_scale) / 0x10000;

  ..................................................................

  TT_Raster_Map

    This structure is  used to describe a target  bitmap (or pixmap)
    to the scan-line  converter.  It _must_ be set  up by the client
    application.

    - The  'rows' field  contains the  total number  of rows  in the
      bitmap

    - The 'width' field gives the number of pixels per row (a bit or
      a byte, depending on the map's nature).

    - The  'cols' field gives  the number  of columns,  i.e., bytes,
      taken by each row in the map buffer.

      ** IMPORTANT **: the 'cols' field  must be a multiple of 4 for
                       pixmaps!

      Typically, its value should  be '(width+7)/8' for bitmaps, and
      '(width+3) & -4' for pixmaps.

    - The 'flow' field gives the map's vertical orientation.

      For example, if  the first bytes of the  bitmap buffer pertain
      to its upper row, the flow is said to be going 'down', and the
      field should  take the  value 'TT_Flow_Down'.  If  these bytes
      pertain to  its lowest  row, the flow  is going 'up',  and the
      value is 'TT_Flow_Up'.

      As an example, the PC video modes use a 'down' flow, where the
      first VRAM  byte corresponds to the upper  and leftmost corner
      of the screen.

    - The 'bitmap' field is a typeless pointer to the map's buffer.

    - The 'size' field  contains the buffer's size in  bytes.  It is
      usually computed as follows:

        size = rows * cols;

    NOTE 1:

      For  bitmaps, the  leftmost-pixel  is related  to the  highest
      (i.e.  most significant) bit  of its byte.  There is currently
      no support for the opposite convention found in some systems.

      (It can  be easily added if  you really need it,  just ask the
      development team.)

      struct
      {
        int     rows;    /* number of rows                    */
        int     cols;    /* number of columns (bytes) per row */
        int     width;   /* number of pixels per line         */
        int     flow;    /* bitmap orientation                */

        void*   bitmap;  /* bit/pixmap buffer                 */
        long    size;    /* bit/pixmap size in bytes          */
      } TT_Raster_Map;


    NOTE 2:

      The functions TT_Get_Outline_Bitmap() or TT_Get_Glyph_Bitmap()
      are  used  to  render   bitmaps  into  a  TT_Raster_Map.   The
      convention  used  is 0  for  the  background,  and 1  for  the
      foreground.  The glyph is simply 'or-ed' to the bitmap buffer.

    NOTE 3:
     
      The        functions        TT_Get_Outline_Pixmap()        and
      TT_Get_Glyph_Pixmap()  are  used  to  render  pixmaps  into  a
      TT_Raster_Map.   Note that  pixels  are drawn  in  spans of  4
      successive  bytes,  when needed.   This  means  that you  must
      ALWAYS  pass  a  clean   pixmap  buffer  to  these  functions.
      Otherwise, garbage could accumulate!

  ..................................................................

  TT_Header

    This structure  is used to  hold the font's header.   Its layout
    and meaning  are defined in  the TrueType specification,  in the
    'head' section.

  ..................................................................

  TT_Horizontal_Header

    This  structure is used  to hold  the font's  horizontal header.
    Its   layout   and  meaning   are   defined   in  the   TrueType
    specification, in the 'hhead' section.

  ..................................................................

  TT_OS2

    This  structure is  used to  hold  the font's  OS/2 table.   Its
    layout and meaning are defined in the TrueType specification, in
    the 'OS/2' section.

  ..................................................................

  TT_Postscript

    This structure is used to hold the font's PostScript table.  Its
    layout and meaning are defined in the TrueType specification, in
    the 'post' section.

  ..................................................................

  TT_Face_Properties

    This structure  is used to  return an opened  face's properties.
    These are:

    - The total  number of  glyphs in the  font, given by  the field
      'num_Glyphs'.

    - The  maximum number  of points  for the  font's  glyphs.  This
      value  is  used to  allocate  the  points  tables of  a  glyph
      container's outline.  It can  be fairly large (like 256 points
      for Roman fonts).

    - The maximum  number of contours  for the font's  glyphs.  This
      value  is used  to allocate  the  contours tables  of a  glyph
      container's outline.  It can be fairly large (over 16, even in
      Roman fonts).

    - The number  of character mappings and name  records within the
      font.  These  values can still  be retrieved through  the APIs
      TT_Get_CharMapCount()  and  TT_Get_Num_Names(),  though  these
      have been _seriously_ deprecated.

    - The number of associated faces.  This number is always 1 for a
      normal TrueType font file.   However, when the face object was
      opened  from  a TrueType  collection,  it  contains the  total
      number of embedded fonts.

    - Pointers to  the face's  header, horizontal header,  OS/2, and
      PostScript tables.

      struct
      {
        TT_UShort  num_Glyphs;        /* number of glyphs in face */
        TT_UShort  max_Points; /* max. numb. of points in a glyph */
        TT_Short   max_Contours;
                         /* maximum number of contours in a glyph */

        TT_ULong  num_Faces;
                          /* 1 for normal TrueType files, and the */
                          /* number of embedded faces for TT      */
                          /* collections                          */

        TT_Header*             header;   /* TrueType header table */
        TT_Horizontal_Header*  horizontal;
                                    /* TrueType horizontal header */
        TT_Vertical_Header*    vertical;
                                    /* TrueType vertical header   */
        TT_OS2*                os2;        /* TrueType OS/2 table */
        TT_Postscript*         postscript;
                                     /* TrueType PostScript table */
      } TT_Face_Properties;

    - Note that  the "vertical" field is  set to NULL  when the font
      file does not contain any vertical metrics.

  ..................................................................

  TT_Stream

    This handle type  defines a stream used to  access a font file's
    data.   A  client application  should  never  deal with  streams
    directly,  but  some engine  extensions  may  later  need it  to
    support more advanced features like font embedding.

  ..................................................................

  TT_Face

    This type defines a handle used to reference a face object.  The
    objects are never accessed  directly by a client application; it
    can only  obtain handles to new  objects, and use  them to query
    specific information or processes.

    See also:

      TT_Open_Face(), TT_Open_Collection(), TT_Close_Face(),
      TT_Get_Face_Properties(), etc.

  ..................................................................

  TT_Instance

    This type defines a handle  used to reference an instance object
    (also called a 'pointsize'  in other type engines).  An instance
    is always  created from  a valid face  object, and  is destroyed
    with it by the engine.

    See also:

     TT_New_Instance(), TT_Close_Instance(),
     TT_Set_Instance_Pointsize(), TT_Set_Instance_Resolutions(),
     etc.

  ..................................................................

  TT_Glyph

    This type defines  a handle used to reference  a glyph container
    object.  A glyph  container is an object owning  tables sized to
    the font's  maximum profile  to hold any  glyph of a  given font
    file.

    It  contains an  outline, some  metrics,  as well  as some  data
    related  to the  way it  should  be processed  by the  scan-line
    converter.

    Note  that a  glyph  container doesn't  contain  any bitmap  nor
    pixmap!

    See also:

      TT_New_Glyph(), TT_Close_Glyph(), TT_Get_Glyph_Metrics(),
      TT_New_Outline(), TT_Get_Glyph_Outline(),
      TT_Get_Glyph_Bitmap(), TT_Get_Glyph_Pixmap()

  ..................................................................

  TT_Error

    This is the type of all error codes returned by the API.  Nearly
    all functions return an error code, set to 0 in case of success.

    A list of all error codes is given in section III.

  ..................................................................

  TT_Engine

    For the sake of re-entrancy,  which isn't supported fully by the
    engine,  it is  possible  to distinguish  'engines' to  separate
    several running instances of the library.  For example, it could
    be used as a DLL shared by several client applications.

    Each  client program  must  begin by  creating  its own  engine,
    through a  call to TT_Init_FreeType().  The engine  must also be
    passed as the first argument of the following functions:

      TT_Open_Face()
      TT_Open_Collection()
      TT_Set_Raster_Palette()
      TT_Get_Outline_Bitmap()
      TT_Get_Outline_Pixmap()
      TT_Done_FreeType()

    Note  that any  FreeType object  pertains to  one  single engine
    (there is no sharing). Closing an engine with TT_Done_FreeType()
    will delete all the objects  that have been allocated within its
    instance.

  ..................................................................

  This distribution  comes with an extension used  to support access
  to a  font's kerning information.   The extension's types  and API
  are defined in the file "ftxkern.h"

--------------------------------------------------------------------
--------------------------------------------------------------------



II. Functions:

  Here is a list of the core library's API.

  NOTE:

    A function's default result is an error code of type TT_Error; a
    list of error codes is given in section III below.

    Some functions return other types, in which case the result type
    is written with its description.

  ..................................................................

  TT_Init_FreeType( TT_Engine*  engine );

    Creates and initializes  a new engine.  Returns a  handle to the
    engine in the '*engine' variable.

    This  call  must  be  performed  before any  other  function  of
    FreeType is  invoked.  The engine  handle must be passed  to the
    following functions:

      TT_Open_Face()
      TT_Open_Collection()
      TT_Set_Raster_Palette()
      TT_Done_FreeType()

  ..................................................................

  TT_Done_FreeType( TT_Engine  engine );

    Finalizes  and destroys  an  engine.  This  call destroys  _all_
    objects that were previously created and used with the engine.

  ..................................................................

  TT_Open_Face( TT_Engine  engine,
                TT_Text*   fontPathName,
                TT_face*   face );

    This  call opens  a font  file, located  by  'fontPathName', and
    returns a handle  to the newly corresponding face  object in the
    handle '*face'.  The object is part of the 'engine' instance.

    Example:

      error = TT_Open_Face( engine, "c:\ttf\wingding.ttf", &face );
      if ( error )
        fprintf( stderr, "could not open face\n" );

    NOTE 1:

      The font file can be  a TrueType collection; in this case, the
      engine will always  open the first embedded font  found in the
      file.

    NOTE 2:

      'TT_Text'  is   usually  defined   as  'char'  by   a  typedef
      declaration.  It may  be a 16bit quantity (or  even wider) for
      some operating systems; see ttconfig.h for details.

  ..................................................................

  TT_Open_Collection( TT_Engine  engine,
                      TT_Text*   collectionPathName,
                      TT_ULong   fontIndex,
                      TT_Face*   face );

    This  call opens  one  of the  font  files found  in a  TrueType
    collection.   The  file  is  selected  through  the  'fontIndex'
    argument.  The first file has index 0.

    Note  that to  know  a collection's  number  of embedded  fonts,
    you'll have to:

      1 - open the first collection font with TT_Open_Face().

      2 - query the face's properties through
          TT_Get_Face_Properties().

    The number of embedded faces is then 'properties->num_Faces'.

    Example:

      TT_Face             face;
      TT_Face_Properties  properties;

      error = TT_Open_Face( engine, "c:\ttf\sample.ttc", &face );
      if ( error ) { ...error .. }
      /* Open first embedded collection font */

      error = TT_Get_Face_Properties( face, &properties );
      if ( error ) { ...error .. }
      /* Get face metrics */

      printf( "There are %d fonts in this collection\n",
              properties->num_Faces );

      TT_Close_Face( face );

      error = TT_Open_Collection( engine, "c:\ttf\sample.ttc", 1,
                                  &face );
      if ( error ) { ...error .. }
      /* Open second font in collection */

    NOTE 1:

      If  the file  isn't a  collection, 'fontIndex'  must  be zero.
      Otherwise, an error will be produced.

    NOTE 2:

      'TT_Text'  is   usually  defined   as  'char'  by   a  typedef
      declaration.  It may  be a 16bit quantity (or  even wider) for
      some operating systems; see ttconfig.h for details.

  ..................................................................

  TT_Set_Raster_Palette( TT_Engine  engine,
                         char*      palette );

    Sets the gray-level palette for  an engine.  The palette is used
    to  create pixmaps  through the  TT_Get_Glyph_Pixmap() function.
    It is an array of five bytes, following the convention:

      palette[0] = background (white)
      palette[1] = light
      palette[2] = medium
      palette[3] = dark
      palette[4] = foreground (black)

  ..................................................................

  TT_Get_Face_Properties( TT_Face              face,
                          TT_Face_Properties*  properties );

    Returns  the  'face'  object's  '*properties'.   This  structure
    contains  various data,  like  the total  number  of glyphs  and
    pointers to some mandatory TrueType tables.

    (See the definition of TT_Face_Properties in section I.)

  ..................................................................

  TT_Set_Face_Pointer( TT_Face  face,
                       void*    data );

    For  convenience  purposes, each  face  object  has a  "generic"
    pointer which value is unused by the engine, but that can be set
    freely by client applications through this function.

    Do what you want with it; it's here to give you a chance to link
    a face object to your own structures and data.

  ..................................................................

  void*  TT_Get_Face_Pointer( TT_Face  face );
  ^^^^
    Returns    a    face     object's    generic    pointer.     See
    TT_Set_Face_Pointer() above.

  ..................................................................

  TT_Flush_Face( TT_Face  face );

    Closes a  given face object's file handler  or descriptor.  This
    is  useful to save  system resources  if your  application opens
    dozens  or even  hundreds of  fonts.  The  face object  is still
    valid, and its file will  be re-opened automatically on the next
    request which requires disk access.

  ..................................................................

  TT_Close_Face( TT_Face  face );

    Closes a  given 'face' object.  This function  will also destroy
    all  the face's  child instances.   The face's  glyphs  won't be
    destroyed, however.

  ..................................................................

  TT_New_Instance( TT_Face       face,
                   TT_Instance*  instance );

    Creates a new  instance object related to the  'face' object.  A
    handle to the newly created instance is returned in 'instance'.

    The default  instance resolution is  96dpi in both  vertical and
    horizontal direction; the default point size is 10pt.

  ..................................................................

  TT_Set_Instance_Resolutions( TT_Instance  instance,
                               TT_UShort    xResolution,
                               TT_UShort    yResolution );

    Sets the  target device resolutions  for a given  instance.  The
    values are expressed  in dots per inch (dpi).   A value of 96dpi
    is typical for  an SVGA display, 72dpi for  a Macintosh one, and
    300 to  6000dpi for printers.   Default value (before a  call to
    this function) is 96dpi.

  ..................................................................

  TT_Set_Instance_CharSize( TT_Instance  instance,
                            TT_F26Dot6   charsize );

    Sets the point size for a given instance.  The size is expressed
    in fractional  (26.6) 'points', where  1 point = 1/72  inch. The
    default value is 10pt (before a call to this function).

    For example, to use a char size of 10pt, call the function with:

        TT_Set_Instance_CharSize( instance, 10 * 64 );

    Fractional char sizes are thus possible.

  ..................................................................

  TT_Set_Instance_CharSizes( TT_Instance  instance,
                             TT_F26Dot6   charWidth,
                             TT_F26Dot6   charHeight );

    Sets  an  instance's glyph  width  and  height independently  in
    fractional  (26.6) points.   Similar  to Set_Instance_CharSize()
    with  the  exception  that  the horizontal  and  vertical  glyph
    dimensions can differ.

  ..................................................................

  TT_Set_Pixel_Sizes( TT_Instance  instance,
                      TT_UShort    pixelWidth,
                      TT_UShort    pixelHeight,
                      TT_F26Dot6   pointSize );

    This function  can be used  to specify directly the  pixel sizes
    and  point size  of a  given instance,  independently  of device
    resolutions.  This is not the  recommended way to do it, but can
    be used for debugging or simplicity in some special cases.

    Note that you _must_ provide a point size!

  ..................................................................

  TT_Set_Instance_Transform_Flags( TT_Instance  instance,
                                   TT_Bool      rotated,
                                   TT_Bool      stretched );

    Sets the transform flags for  a given instance.  These flags are
    passed to the interpreter each time a glyph is loaded within the
    instance.  Their  role is to notify the  glyph hinting mechanism
    that the resulting  glyph will be transformed in  a special way.
    Setting  one of these  flags to  true usually  disables hinting,
    though this behaviour varies with each font file.

    NOTE:

      The  glyph   loader  doesn't  perform  the   rotation  or  the
      stretching itself; this must  be done explicitly by the client
      application.  Use the function TT_Transform_Outline() for that
      purpose.

  ..................................................................

  TT_Get_Instance_Metrics( TT_Instance           instance,
                           TT_Instance_Metrics*  imetrics );

     This call returns a given instance's current metrics.  They are
     returned  in the  'imetrics' structure,  which  contains, among
     other  things,  the  current   point  size,  ppem,  and  device
     resolution (horizontal and vertical).

  ..................................................................

  TT_Set_Instance_Pointer( TT_Instance  instance,
                           void*        data );

    For convenience  purposes, each instance object  has a "generic"
    pointer which value is unused by the engine, but that can be set
    freely by client applications through this function.

    Do what you want with it, it's here to give you a chance to link
    a face object to your own structures and data.

  ..................................................................

  void*  TT_Get_Instance_Pointer( TT_Instance  instance )
  ^^^^

    This function  returns an instance object's  generic pointer set
    through TT_Set_Instance_Pointer().

  ..................................................................

  TT_Done_Instance( TT_Instance  instance );

    Closes a given instance  object, destroying its associated data.
    Note that this is performed  automatically when a face is closed
    on all its child  instances.  However, explicit deallocation can
    help in freeing the memory used by the application earlier.

  ..................................................................

  TT_New_Glyph( TT_Face    face,
                TT_Glyph*  glyph );

    Creates  a  new glyph  container  for  the  glyphs of  the  font
    described by the  'face' handle.  A pointer to  the container is
    returned in 'glyph'.  The face is said to be the glyph's parent.

    NOTE:

      A glyph is destroyed with its parent face object.  However, it
      is possible to delete it explicitly with TT_Done_Glyph().

  ..................................................................

  TT_Done_Glyph( TT_Glyph  glyph );

    Discards a glyph container.  This is also done automatically for
    all glyphs when closing its parent face object.

  ..................................................................

  TT_Load_Glyph( TT_Instance  instance,
                 TT_Glyph     glyph,
                 TT_UShort    glyphIndex,
                 TT_UShort    loadFlags );

    Loads and  processes (scales  and/or hints) a  glyph at  a given
    'instance' into the 'glyph' container.

    Note  that 'glyph' and  'instance' must  have the  _same_ parent
    face object, or an error message will be returned.

    'glyph_index'  is the  glyph's index  as found  in  the TrueType
    file.  It is  _not_ a character code (see  the charmap functions
    below).

    'load_flags' is  an integer that specifies  which operations are
    to be performed on  the loaded glyph.  The following values/bits
    are used:

      TTLOAD_SCALE_GLYPH

        Indicates that  the glyph must  be scaled to  the instance's
        resolution.   The pixel  coordinates returned  in  the glyph
        outline  structure   (see  below)  are   then  expressed  in
        fractional  pixels  represented  in  the  26.6  fixed  point
        floating format defined by Apple as 'F26Dot6'.

        If  scaling is  disabled,  the coordinates  returned in  the
        outline  structure  are  integer  font  units,  also  called
        'FUnits' by the TrueType specification.

      TTLOAD_HINT_GLYPH

        This flag is only valid  when scaling is on.  It informs the
        loader that the glyph  must be hinted (i.e., grid-fitted for
        optimal display).  Note that  hinting will occur only if the
        instance's  transformations   and  metrics  allow   it  (for
        example, most font programs disable hinting automatically in
        case of rotation or stretching).

        When  loading a hinted  glyph, the  metrics computed  by the
        loader,   including   the  bounding   box,   will  also   be
        grid-fitted.

   NOTE:

     You can  also use the constant TTLOAD_DEFAULT,  which is simply
     the union of  TTLOAD_SCALE_GLYPH and TTLOAD_HINT_GLYPH for most
     'typical' loads.

  ..................................................................

  TT_Get_Glyph_Outline( TT_Glyph     glyph,
                        TT_Outline*  outline );

    This  call returns  the  glyph's 'outline'.   This  is a  simple
    structure which  contains pointers to the data  used to describe
    an   outline  to   the  rasterizer.    See  the   definition  of
    TT_Outline in section I.

  ..................................................................

  TT_Get_Glyph_Metrics( TT_Glyph           glyph,
                        TT_Glyph_Metrics*  metrics );

    Extracts  the glyph's metrics  and copy  them to  the '*metrics'
    structure.  Its format is described in section I.

    When the glyph  has been loaded without scaling,  the values are
    expressed in FUnits (integers relative to the original font grid
    called the EM Square).

    When  the glyph  has been  loaded _with_  scaling, which  is the
    default, the  values are expressed  in fractional pixels  in the
    26.6 fixed  point float  format called F26Dot6  (where 1  unit =
    1/64th of a pixel).

    When the  glyph has  been loaded with  hinting, the  metrics are
    also  grid-fitted,  including  the  bounding box.   To  get  the
    un-fitted bbox,  just call TT_Get_Outline_BBox()  on the glyph's
    outline.

  NOTE:

    BBox fitting occurs according to the following scheme:

      #define  FLOOR( x )    ( (x) & -64 )
      #define  CEILING( x )  ( ( (x) + 63 ) & -64 )

        xMin = FLOOR( xMin );
        yMin = FLOOR( yMin );
        xMax = CEILING( xMax );
        yMax = CEILING( yMax );

    This means that the outline's  width and height in pixels can be
    computed simply from the fitted bbox, as:

      (xMax-xMin)/64   and   (yMax-yMin)/64

  ..................................................................

  TT_Get_Glyph_Bitmap( TT_Glyph        glyph,
                       TT_Raster_Map*  bitmap,
                       TT_F26Dot6      xOffset,
                       TT_F26Dot6      yOffset );

    This call converts  the vectorial glyph representation contained
    in the object handled by 'glyph' into a bitmap.

    The  target  bitmap  is   described  by  the  'bitmap'  pointer.
    Clipping will  be done  if necessary.  You  can also  specify an
    offset to be applied  before the scan-line conversion; 'xOffset'
    and 'yOffset'  must be expressed  in fractional pixels  (where 1
    unit = 1/64th pixel).

    NOTE 1:

      Choosing non integer pixel  offsets, i.e., values of 'xOffset'
      and  'yOffset' that  are not  multiples of  64, will  ruin the
      hinting  performed  by  the  interpreter, and  result  in  bad
      rendering at small sizes.

    NOTE 2:

      The glyph's  point coordinates  must be scaled  before calling
      this  function.  Never call  this function  with a  glyph that
      were loaded with no scaling!

  ..................................................................

  TT_Get_Glyph_Pixmap( TT_Glyph        glyph,
                       TT_Raster_Map*  pixmap,
                       TT_F26Dot6      xOffset,
                       TT_F26Dot6      yOffset );

    This call converts  the vectorial glyph representation contained
    in  the  object handled  by  'glyph'  into  a pixmap  (i.e.,  an
    8-bit/pixel map).  The result  is an anti-aliased version of the
    glyph (a.k.a. font-smoothing).

    The target  pixmap is described  by the 'pixmap'  pointer.  Note
    that  its  width  _must_ be  a  multiple  of  4.  For  a  pixmap
    definition and description, see Section I.

    As  with TT_Get_Glyph_Bitmap(),  you can  specify offsets  to be
    applied before  the rendering  ('xOffset' and 'yOffset'  must be
    expressed in fractional pixel coordinates).

    NOTE 1:

      You  don't   need  to  supply  a  temporary   bitmap  for  the
      anti-aliaser.  The rasterizer uses  its own scheme to optimize
      memory uses.

    NOTE 2:

      The glyph's  point coordinates  must be scaled  before calling
      this function.  This means that  you should never call it with
      a glyph which has been loaded without scaling!

    NOTE 3:

      The  pixmap passed  to this  function should  always  be EMPTY
      before the call.  If not, garbage will accumulate!

  ..................................................................

  TT_New_Outline( TT_UShort    numPoints,
                  TT_UShort    numContours,
                  TT_Outline*  outline );

    Creates a new outline  object.  This function creates the arrays
    necessary to hold 'numPoints' points and 'numContours' contours,
    and set 'outline's pointers to them.

    The new outline owns the arrays, and they will be destroyed with
    it through TT_Done_Outline().

    NOTE 1:

      Outlines  created   with  this  function   are  called  "user"
      outlines,   in  contrast   with  the   outlines   returned  by
      TT_Get_Glyph_Outline(),  which   fields  refer  to   the  data
      contained within  a glyph object (i.e., these  outlines do not
      own the arrays they refer to).

     NOTE 2:

      User  outlines  aren't  tracked  by the  engine,  which  means
      they're not  destroyed by  a TT_Done_FreeType().  You  have to
      explicitly  discard them  through  TT_Done_Outline() to  avoid
      memory leaks.

  ..................................................................

  TT_Done_Outline( TT_Outline*  outline );

    Deletes an outline's  data.  Note that you need  not destroy the
    outlines returned by  TT_Get_Glyph_Outline(), only those created
    by TT_New_Outline().

  ..................................................................

  TT_Copy_Outline( TT_Outline*  source,
                   TT_Outline*  target );

    Copies the content  of the 'source' outline into  the content of
    the 'target'  outline.  The two outlines must  have been created
    with   the  same   dimensions  (num_points   and  num_contours),
    otherwise this function will return an error code.

  ..................................................................

  TT_Transform_Outline( TT_Glyph_Outline*  outline,
                        TT_Matrix*         matrix );

    Applies a simple transformation matrix on a given outline.  This
    will  multiply each  point coordinate  vector by  a  2x2 matrix,
    which coefficients are written in the 16.16 fixed float format.

    Rotation can be performed with this function.

    NOTE:

      This function takes  an outline, and not a  glyph handle, as a
      parameter.  This  'feature' lets you  apply transformations on
      your own copies of glyphs.

  ..................................................................

  TT_Translate_Outline( TT_Glyph_Outline*  outline,
                        TT_Pos             xOffset,
                        TT_Pos             yOffset );

    Applies a simple translation on a given outline.

    NOTE:

      This function takes  an outline, and not a  glyph handle, as a
      parameter.  This 'feature' lets  you apply translation to your
      own copies of glyphs.

  ..................................................................

  TT_Get_Outline_Bitmap( TT_Outline*     outline,
                         TT_Raster_Map*  bitmap );

    Renders an outline  into a bitmap.  The latter  must be setup by
    the  user before  the  call (i.e.,  it  is not  created by  this
    function, instead it must be provided by the user).

  ..................................................................

  TT_Get_Outline_Pixmap( TT_Outline*     outline,
                         TT_Raster_Map*  pixmap );

    Renders an outline  into a pixmap.  The latter  must be setup by
    the  user before  the  call (i.e.,  it  is not  created by  this
    function, instead it must be provided by the user).

  NOTE:

    The pixmap passed  to this function must always  be EMPTY before
    the call.  Otherwise, garbage may accumulate!

  ..................................................................

  TT_Get_Outline_BBox( TT_Outline*  outline,
                       TT_BBox*     bbox );

    Returns an outline's bounding box in the 'bbox' structure.  Note
    that the returned coordinates are not grid fitted!

  NOTE:

    The current release of  FreeType (1.0) does compute the bounding
    box for  the outline's control  points, and not the  "exact" box
    based on Bezier arcs extrema.   Hence, the bbox returned by this
    function  may be  slightly larger  than necessary  if  the glyph
    doesn't have  control points at its  extrema, or if  it has been
    rotated.

  ..................................................................

  void  TT_Transform_Vector( TT_Pos*     x,
  ^^^^                       TT_Pos*     y,
                             TT_Matrix*  matrix );

    Applies a 2x2 matrix to a vector.

  ..................................................................

  TT_Matrix_Multiply( TT_Matrix*  a,
                      TT_Matrix*  b );

    Multiplies  one   matrix  with   another  --  it   will  compute
    b := a * b.

  ..................................................................

  TT_Matrix_Invert( TT_Matrix*  matrix );

    Inverts a  matrix.  In case  of failure, returns the  error code
    TT_Err_Divide_By_Zero if the matrix cannot be inverted.

  ..................................................................

  int  TT_Get_CharMapCount( TT_Face  face );
  ^^^

    Gets the  number of character  mappings present in  the TrueType
    file described  by the 'face' handle.  Returns -1 if the  handle
    is invalid.

  IMPORTANT NOTE: ********

    This function  is deprecated.  Get the number of  character maps
    from  the  `num_CharMaps' field  in  the  structure  returned by
    TT_Get_Face_Property() instead.

  ..................................................................

  TT_Get_CharMap_ID( TT_Face     face,
                     TT_UShort   charmapIndex,
                     TT_UShort*  platformID,
                     TT_UShort*  encodingID );

    Returns the  platform ID  and platform-specific encoding  ID for
    the charmap  numbered 'charmapIndex' in the  'face' object.  The
    total  number of  character mapping  tables is  returned  by the
    TT_Get_CharMap_Count() function described above.

  ..................................................................

  TT_Get_CharMap( TT_Face      face,
                  TT_UShort    charmapIndex,
                  TT_CharMap*  charMap );

    Returns a handle for  the character map number 'charmapIndex' of
    'face'.   The handle  is placed  in '*charMap'  and can  be used
    later for fast lookup with the TT_Char_Index() API.

    Charmap  objects  are automatically  destroyed  when their  face
    object is destroyed.

  ..................................................................

  TT_UShort  TT_Char_Index( TT_CharMap  charMap,
  ^^^^^^^^^                 TT_UShort   charCode );

    Applies a  charMap to  translate a charCode  into a  glyph index
    that can  be used to  load and address  a glyph in  the TrueType
    file.  In case of error, the undefined glyph (0) is returned.

    The charmap handle can be obtained with TT_Get_CharMap().

  ..................................................................

  int  TT_Get_Name_Count( TT_Face  face );

    Gets the  number of name strings  found in a  face's name table.
    This function will return -1 if the face handle is invalid.

  IMPORTANT NOTE: ********

    This function  is deprecated.   Get the  number of  name strings
    from  the  `num_Names'  field  in   the  structure  returned  by
    TT_Get_Face_Property() instead.

  ..................................................................

  TT_Get_Name_ID( TT_Face     face,
                  TT_UShort   nameIndex,
                  TT_UShort*  platformID,
                  TT_UShort*  encodingID,
                  TT_UShort*  languageID,
                  TT_UShort*  nameID );

    Returns the  ID of  a given name  string, indexed by  the number
    'nameIndex' in  a given face.  The  name index ranges  from 0 to
    the value returned by TT_Get_Name_Count() minus one.

    Each string has a platformID, encodingID, languageID and nameID,
    as defined by the TrueType specification.

    The platformID is typically in  the 0..3 range.  Some font files
    have  unusual name  table entries;  these can  be  detected from
    their platformID which is larger than 3.

  ..................................................................

  TT_Get_Name_String( TT_Face      face,
                      TT_UShort    nameIndex,
                      TT_String**  stringPtr,
                      TT_UShort*   length );

    Returns  a  name string's  address  and  length.   Note that  an
    invalid name table entry always returns NULL for 'stringPtr' and
    a zero length.

    NOTE:

      The  string belongs  to  the  face object  and  should not  be
      written to or freed by the client application.

  ..................................................................

  TT_Init_Kerning_Extension( TT_Engine  engine );

    Initializes the kerning extension for a given engine.  This must
    be called  just after the  engine creation, and before  any face
    object allocation.  Example:

      TT_Init_FreeType( &engine );
      TT_Init_Kerning_Extension( engine );

  ..................................................................

  TT_Get_Kerning_Directory( TT_Face      face,
                            TT_Kerning*  directory );

    Queries the  kerning directory  found in a  face object.   If no
    kerning  table  is  found   in  the  TrueType  file,  the  error
    TT_Err_Table_Is_Missing will be returned.

    You  can  access  the  subtables  through the  pointers  of  the
    directory.  However,  by default,  the directory is  only loaded
    when a face object is created.  You must load the subtables that
    interest you with a call to TT_Load_Kerning_Table().

    The  layout of  all kerning  structures is  defined in  the file
    "lib/extend/apikern.h".  Both  formats (0 and 2)  are exposed by
    this API.

    NOTE:

      This function must be  called after the kerning extension were
      initialized.

  ..................................................................

  TT_Get_Font_Data( TT_face   face,
                    TT_Long   tag,
                    TT_Long   offset,
                    void*     buffer,
                    TT_Long*  length );

    Gets font  or table data.   Similar to the GetFontData()  API of
    the  Windows world.   You  can use  the  macro MAKE_TT_TAG()  to
    generate TrueType table tags from character descriptions, like

      MAKE_TT_TAG( 'e','b','l','c' )

  ..................................................................

  TT_Load_Kerning_Table( TT_Face    face,
                         TT_UShort  kernIndex );

    Loads the kerning subtable number 'kern_index' into memory.  The
    subtable can  be accessed through  the pointers provided  by the
    kerning     directory,    obtained     from     a    call     to
    TT_Get_Kerning_Directory().

    Note that the interpretation of  the kerning data is left to the
    client  application.  Read the  TrueType specification  for more
    information on kerning encoding.

    NOTE:

      This function must be  called after the kerning extension were
      initialized.

  ..................................................................

  TT_Init_Post_Extension( TT_Engine  engine );

    Initializes the PostScript name extension to load the PostScript
    glyph names given in the 'post' table.  This must be called just
    after  creation  of  the  engine,  and before  any  face  object
    allocation.  See description of TT_Get_PS_Name() for an example.

  ..................................................................

  TT_Load_PS_Names( TT_Face   face,
                    TT_Post*  post );

    Loads the PostScript glyph names into memory.  This must be done
    before  TT_Get_PS_Name() is  called.  In  case of  error, either
    TT_Err_Invalid_Post_Table or TT_Err_Invalid_Post_Table_Format is
    returned.  See description of TT_Get_PS_Name() for an example.

  ..................................................................

  TT_Get_PS_Name( TT_Face      face,
                  TT_UShort    index,
                  TT_String**  PSname );

    Get  the PostScript  glyph  name  for a  given  glyph index.   A
    pointer to the name is returned in 'PSname'.  Example:

      ...
      TT_Post  post;
      char*    PSname;

      ...
      TT_Init_Post_Extension( engine );
      TT_Load_PS_Names( face, &post );

      ...
      TT_Get_PS_Name( face, index, &PSname );


    NOTE:

      You must not alter the PostScript glyph name string returned
      by PSname.


--------------------------------------------------------------------
--------------------------------------------------------------------


III. Error Messages:

  Most functions return an error  code, typed to TT_Error.  A return
  value of zero indicates no error.  The error values are defined in
  the file 'freetype.h'.


  Error   Unprefixed               Error
  Code    Macro Name               Description
  ------------------------------------------------------------------

  0x0000  Ok                       Successful function call.
                                   Always 0!

  ----------------- high-level API error codes ---------------------

  The following  error codes are  returned by the high-level  API to
  indicate an invalid client request.

  0x0001  Invalid_Face_Handle      An invalid face object handle was
                                   passed to an API function.

  0x0002  Invalid_Instance_Handle  An invalid instance object handle
                                   was passed to an API function.

  0x0003  Invalid_Glyph_Handle     An invalid glyph container handle
                                   was passed to an API function.

  0x0004  Invalid_CharMap_Handle   An invalid charmap handle was
                                   passed to an API function.

  0x0005  Invalid_Result_Address   An output parameter (a result)
                                   was given a NULL address in an
                                   API call.

  0x0006  Invalid_Glyph_Index      An invalid glyph index was passed
                                   to one API function.

  0x0007  Invalid_Argument         An invalid argument was passed to
                                   one API function. Usually, this
                                   means a simple out-of-bounds
                                   error.

  0x0008  Could_Not_Open_File      The pathname passed doesn't point
                                   to an existing or accessible
                                   file.

  0x0009  File_Is_Not_Collection   Returned by TT_Open_Collection
                                   when trying to open a file which
                                   isn't a collection.

  0x000A  Table_Missing            A mandatory TrueType table is
                                   missing from the font file.
                                   Denotes a broken font file.

  0x000B  Invalid_Horiz_Metrics    The font's HMTX table is broken.
                                   Denotes a broken font.

  0x000C  Invalid_CharMap_Format   A font's charmap entry has an
                                   invalid format.  Some other
                                   entries may be valid though.

  0x000D  Invalid_PPem             Invalid PPem values specified,
                                   i.e. you're accessing a scaled
                                   glyph without having called
                                   TT_Set_Instance_CharSize() or
                                   TT_Set_Instance_PixelSizes().

  0x0010  Invalid_File_Format      The file isn't a TrueType font or
                                   collection.

  0x0020  Invalid_Engine           An invalid engine handle was
                                   passed to one of the API
                                   functions.

  0x0021  Too_Many_Extensions      The client application is trying
                                   to initialise too many
                                   extensions.  The default max
                                   extensions number is 8.

  0x0022  Extensions_Unsupported   This build of the engine doesn't
                                   support extensions

  0x0023  Invalid_Extension_Id     This error indicates that the
                                   client application is trying to
                                   use an extension that has not
                                   been initialized yet.

  0x0080  Max_Profile_Missing      The max profile table is missing
                                   from the font file.
                                   => broken font file

  0x0081  Header_Table_Missing     The font header table is missing
                                   from the font file.
                                   => broken font file

  0x0082  Horiz_Header_Missing     The horizontal header is missing.

  0x0083  Locations_Missing        The locations table is missing.

  0x0084  Name_Table_Missing       The name table is missing.

  0x0085  CMap_Table_Missing       The character encoding tables are
                                   missing.

  0x0086  Hmtx_Table_Missing       The Hmtx table is missing.

  0x0087  OS2_Table_Missing        The OS/2 table is missing.

  0x0088  Post_Table_Missing       The PostScript table is missing.

  ----------------- memory component error codes -------------------

  0x0100  Out_Of_Memory            An operation couldn't be
                                   performed due to memory
                                   exhaustion.

  ----------------- file component error codes ---------------------

  0x0200  Invalid_File_Offset      Trying to seek to an invalid
                                   portion of the font file.
                                   Denotes a broken file.

  0x0201  Invalid_File_Read        Trying to read an invalid portion
                                   of the font file.  Denotes a
                                   broken file.

  0x0202  Invalid_Frame_Access     Trying to frame an invalid
                                   portion of the font file.
                                   Denotes a broken file.

  ----------------- glyph loader error codes -----------------------

  These errors  are produced  by the glyph  loader.  They  denote an
  invalid glyph record within the font file.

  0x0300  Too_Many_Points          The glyph has too many points to
                                   be valid for its font file.

  0x0301  Too_Many_Contours        The glyph has too many contours
                                   to be valid for its font file.

  0x0302  Invalid_Composite_Glyph  A composite glyph's description
                                   is broken.

  0x0303  Too_Many_Ins             The glyph has too many
                                   instructions to be valid for its
                                   font file.

  ----------------- byte-code interpreter error codes --------------

  These  error   codes  are  produced  by   the  TrueType  byte-code
  interpreter.  They usually indicate a broken font file or a broken
  glyph within a font.

  0x0400  Invalid_Opcode           Found an invalid opcode in a
                                   TrueType byte-code stream.

  0x0401  Too_Few_Arguments        An opcode was invoked with too
                                   few arguments on the stack.

  0x0402  Stack_Overflow           The interpreter's stack has been
                                   filled up and operations can't
                                   continue.

  0x0403  Code_Overflow            The byte-code stream runs out of
                                   its valid bounds.

  0x0404  Bad_Argument             A function received an invalid
                                   argument.

  0x0405  Divide_By_Zero           A division by 0 operation was
                                   queried by the interpreter
                                   program.

  0x0406  Storage_Overflow         The program tried to access data
                                   outside of its storage area.

  0x0407  Cvt_Overflow             The program tried to access data
                                   outside of its control value
                                   table.

  0x0408  Invalid_Reference        The program tried to reference an
                                   invalid point, zone or contour.

  0x0409  Invalid_Distance         The program tried to use an
                                   invalid distance.

  0x040A  Interpolate_Twilight     The program tried to interpolate
                                   twilight points.

  0x040B  Debug_Opcode             The now invalid 'debug' opcode
                                   was found in the byte-code
                                   stream.

  0x040C  ENDF_In_Exec_Stream      A misplaced ENDF was encountered
                                   in the byte-code stream.

  0x040D  Out_Of_CodeRanges        The program tried to allocate too
                                   much code ranges (this is really
                                   an engine internal error that
                                   should never happen).

  0x040E  Nested_DEFS              Nested function definitions
                                   encountered.

  0x040F  Invalid_CodeRange        The program tried to access an
                                   invalid code range.

  0x0410  Invalid_Displacement     The program tried to use an
                                   invalid displacement.

  0x0411  Execution_Too_Long       In order to get rid of "poison"
                                   fonts, the interpreter produces
                                   this error when more than a
                                   million opcodes have been
                                   interpreted in a single glyph
                                   program.  This detects infinite
                                   loops softly.

  ----------------- internal failure error codes -------------------

  These error codes are produced  if an incoherent library state has
  been detected.   All of these reflect  a severe bug  in the engine
  (or a severe  memory corruption due to massive  overwrites by your
  application into the library's data)!

  If you  do encounter a  font that makes  one of the  test programs
  produce such an error, please report it!

  0x0500  Nested_Frame_Access
  0x0501  Invalid_Cache_List
  0x0502  Could_Not_Find_Context
  0x0503  Unlisted_Object

  ----------------- scan-line converter error codes ----------------

  These  error codes are  produced  by  the raster  component.  They
  indicate that   an outline structure  was incoherently  set up, or
  that you're trying to render a horribly complex glyph.

  They should be _extremely_ rare, however.

  0x0600  Raster_Pool_Overflow     Render pool overflow. This should
                                   never happen in this release.

  0x0601  Raster_Negative_Height   A negative height was produced.

  0x0602  Raster_Invalid_Value     The outline data wasn't set
                                   properly. Check that:
                                     points >= endContours[contours]

  0x0603  Raster_Not_Initialized   You did not call
                                   TT_Init_FreeType()!

  ----------------- engine extensions error codes ------------------

  The engine's extensions also provide their own error codes, within
  their own group:

  0x0A00  Invalid_Kerning_Table_Format
                                   A kerning subtable format was
                                   found invalid in this font.

  0x0A01  Invalid_Kerning_Table    A kerning table contains illegal
                                   glyph indices.

  0x0B00  Invalid_Post_Table_Format
                                   The post table format specified
                                   in the font is invalid.

  0x0B01  Invalid_Post_Table       The post table contains illegal
                                   entries.

--- end of apiref.txt ---
