                        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
  conflict of names with other packages at link time.

  The reference for extensions of  the FreeType library can be found
  in the file `apirefx.txt'.



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I. Types
========

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


  TT_Bool

    Can be either non-zero (true) or zero (false).

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

  TT_Fixed

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

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

  TT_FWord

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

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

  TT_UFWord

    An unsigned 16-bit type.

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

  TT_String
  TT_Char
  TT_Byte

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

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

  TT_Short
  TT_UShort
  TT_Long
  TT_ULong

    These  four types  are aliases  for 16-bit  integer  (signed and
    unsigned) and 32-bit integer types (signed and unsigned).

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

  TT_Int

    A signed  type, either 16-bit  or 32-bit, whichever is  the most
    efficient for the target platform.

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

  TT_F2Dot14

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

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

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

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

  TT_F26Dot6

    A  26.6 fixed  float integer  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  interpretation 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 measured in notional font units
    when the glyph has been 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_F26Dot6  x;
        TT_F26Dot6  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  bounding box.   Used  by the
    TT_Get_Outline_BBox() API.

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

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

  TT_Outline

    Outlines are represented from now  on as a class in itself, with
    their own API.

    This   structure  is   used  to   describe  a   vectorial  glyph
    representation to the rasterizer.  It consists of several fields
    as 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 have 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  called `points'.  The `flags' array holds a flag
      for each point indicating its type.

      Currently, only  the first bit  (bit 0, the  least significant
      bit) of each byte is meaningful to the rasterizer.  If set, it
      indicates that the  point is _on_ the curve.   If not set, the
      point is  said to  be _off_  the curve.  It  is 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 indices:

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

      Hence, `contours[0]' holds the index  of the last point of the
      first  contour.  The  second  contour starts  at point  number
      `contours[0]+1', and ends at 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 greater  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:

      If  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:

      If  this boolean is  set, the  scan-line converter  performs a
      second sweep on the bitmap/pixmap to detect vertical drop-out.
      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  which  method applies  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  more  recent modes  4  and  5  introduced in  the  newest
      TrueType specification (Version 1.66) are fully supported.

      An invalid value (i.e.,  not 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  new  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 while executing  TT_Done_FreeType(), they  must be
      explicitly discarded 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, applicable for
    either horizontal or vertical  layout.  The values are expressed
    in  fractional  pixels  (26.6  format) if  scaling  was  active,
    otherwise in FUnits.

    The  main  idea  was  to  accomodate vertical  text  layouts  by
    eradicating    the    two    explicit   `leftSideBearing'    and
    `advanceWidth' names.

    The interpretation of the fields varies with the text layout:

      bearingX: Also   known  as  the   `left  side   bearing'.   In
                horizontal metrics, this  value gives the horizontal
                distance from  the pen position to  the glyph's bbox
                xmin, otherwise it specifies the vertical distance.

      bearingY: Also  known as the  `top side bearing', this  is the
                vertical distance  from the baseline  to the glyph's
                bbox  ymax  in  horizontal  metrics,  otherwise  the
                horizontal distance.

      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 conventions  inherent to 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 it is not
      necessary to  increase the  pen position by  `bearingX' and/or
      `bearingY'  before  writing  a  glyph.   Text  output  can  be
      performed with simple lines such as:

        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
        }

      For an example see the file `test/ftstring.c'.

    NOTE 2:

      This structure has changed from the beta version of FreeType.

    NOTE 3:

      FreeType  only  implements  TT_Get_Glyph_Metrics()  to  return
      horizontal  metrics.   For  extracting  vertical  metrics  you
      should use TT_Get_Glyph_Big_Metrics().

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

  TT_Big_Glyph_Metrics

    This structure is used to return the metrics of a glyph for both
    horizontal and vertical layout.

    The `linearXXX' fields represent unhinted scaled metrics values.
    They can be useful for applications which need to compute device
    independent  placement  of glyphs.   Applying  these metrics  to
    hinted glyphs will in most cases ruin the grid fitting performed
    by the bytecode interpreter.

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

        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_Pos   linearHoriBearingX;  /* lin. scaled hor. lsb.  */
        TT_Pos   linearHoriAdvance;   /* lin. scaled hor. adv.  */

        TT_Pos   linearVertBearingY;  /* lin. scaled vert. tsb. */
        TT_Pos   linearVertAdvance;   /* lin. scaled vert. adv. */
      }

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

  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 notional units (in funits) in fractional pixels (in 26.6
    fixed float format), e.g.:

      TT_FUnit    em_distance;
      TT_F26Dot6  frac_distance;
      TT_Fixed    x_scale;

      frac_distance = (em_distance * x_scale) / 0x10000;

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

  TT_Raster_Map

    This structure  is used to  specify a target bitmap  (or pixmap)
    for 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!

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

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

      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', otherwise  the flow  is going
      `up', and the value is `TT_Flow_Up'.

      To  cite 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:

      TT_Get_Outline_Bitmap()  resp. 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:
     
      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, only if  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.

    Note that since  FreeType 1.3, we support fonts  without an OS/2
    table (mainly  old but  popular Mac fonts).   In this  case, the
    table's `version' field will be set to 0xFFFF by the loader, and
    all other fields will be zeroed.

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

  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_Hdmx

    This  structure is  used to  hold the  font's  horizontal device
    metrics.   Its layout  and meaning  are  defined in  the in  the
    `hdmx' section of the TrueType specification.

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

  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 and horizontal header,  the OS/2
      and PostScript tables, and the horizontal device metrics.

      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 resp.    */
                          /* 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_Hdmx*               hdmx;       /* TrueType hdmx table */

      } TT_Face_Properties;

    - Note that the `vertical' field is set to NULL if the font file
      does not contain any vertical metrics.

    - Note also that since version 1.3 we support font files without
      an OS/2 table.  See the definition of TT_OS2 for more details.

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

  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 need  it to  support more
    advanced features like sbit support.

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

  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_Done_Instance(),
     TT_Set_Instance_CharSizes(), 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  or
    pixmap!

    See also:

      TT_New_Glyph(), TT_Done_Glyph(), TT_Load_Glyph(),
      TT_Get_Glyph_Metrics(), TT_Get_Glyph_Big_Metrics(),
      TT_Get_Glyph_Outline(), TT_Get_Glyph_Bitmap(),
      TT_Get_Glyph_Pixmap()

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

  TT_CharMap

    This type defines  a handle used to reference  a charMap object.
    A charMap is  an object owning the tables  needed to perform the
    mapping from  characters code to  glyphs numbers.  A  charMap is
    always created from  a valid face object, and  is destroyed with
    it by the engine.

    See also:

     TT_Get_CharMap(), TT_Char_Index().

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

  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  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_Gray_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.



--------------------------------------------------------------------
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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 documented with its description.

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

  TT_FreeType_Version( int*  major, int*  minor );

    Queries the major and minor version of the library.

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

  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_Gray_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  16-bit 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 fonts found in a TrueType collection.
    The  font is  selected  through the  `fontIndex' argument.   The
    first font has index 0.

    Note  that to  know  a collection's  number  of embedded  fonts,
    you will 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;


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

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

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

      TT_Close_Face( face );

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

    NOTE 1:

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

    NOTE 2:

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

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

  TT_Set_Raster_Gray_Palette( TT_Engine  engine,
                              TT_Byte*   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 for more
    details.

    Note  that since version  1.3, FreeType  supports fonts  with no
    OS/2  table, like  many old  Mac fonts.   See the  definition of
    TT_OS2 for more details.

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

  TT_Get_Face_Metrics( TT_Face     face,
                       TT_UShort   firstGlyph,
                       TT_UShort   lastGlyph,
                       TT_Short*   leftBearings,
                       TT_UShort*  widths,
                       TT_Short*   topBearings,
                       TT_UShort*  heights );

   This  function  returns  the  original  horizontal  AND  vertical
   metrics for a given face `face' and a given glyph range specified
   by `firstGlyph' and `lastGlyph' as found in the `hmtx' and `vmtx'
   tables.    These   are  the   glyphs'   left-side  bearings   (in
   `leftBearings') and  horizontal advance widths  (in `widths'), as
   well as top-side bearings (in `topBearings') and vertical advance
   heights (in `heights').   If you aren't interested in  any of the
   metrics fields, simply set its value to NULL.
 
   All are expressed in font units, a.k.a. EM units.

   The metrics arrays must be allocated by the client program.
 
   IMPORTANT NOTE:

     As  vertical metrics  are  optional in  a  TrueType font,  this
     function will return an error (TT_Err_No_Vertical_Data) if this
     function is  called on such a face  with non-NULL `topBearings'
     or `heights' arguments.
 
     If a  font has  no vertical data,  the `vertical' field  in its
     properties structure is set to NULL.

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

  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 is 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  will not 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 12pt, call the function with:

        TT_Set_Instance_CharSize( instance, 12 * 64 );

    Fractional point sizes are thus possible.

    Call this function after TT_Set_Instance_Resolutions().

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

  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.

    Call this function after TT_Set_Instance_Resolutions().

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

  TT_Set_Instance_PixelSizes( 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!

    Call this function after TT_Set_Instance_Resolutions().

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

  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 automatically; 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 is 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, otherwise an error message will be returned.

    `glyph_index'  is the  glyph's index  as found  in  the TrueType
    font.  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 (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.

      TTLOAD_PEDANTIC

        Starting with FreeType version 1.3, the bytecode interpreter
        can  ignore  even   more  errors  (like  out-of-bound  array
        accesses).  Using this flag it is possible to force TrueType
        compliant interpretation of font programs.

      TTLOAD_IGNORE_GLOBAL_ADVANCE_WIDTH

        A flag  to handle monospaced fonts with  an incorrect global
        advance  width in  the  `hhea' table.   If  set, the  actual
        advance width value  of a particular glyph will  be used; if
        unset, the  advance widths for  all glyphs are forced  to be
        equal to the global value.


   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 copies them  to the `*metrics'
    structure.  Its format is described in section I.

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

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

    If the glyph has been  loaded with hinting, the metrics are also
    grid-fitted, including  the bounding box.  To  get the un-fitted
    bbox, 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, namely

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

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

  TT_Get_Glyph_Big_Metrics( TT_Glyph               glyph,
                            TT_Big_Glyph_Metrics*  metrics );

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

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

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

    If 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 1:

    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 bounding box, namely

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

  NOTE 2:

    The  vertBearingX value  in  `metrics' cannot  be extracted  for
    outline  glyphs --  it  is defined  for  embedded bitmaps  only.
    Instead,  it  is set  to  (xMin-xMax)/2;  this  will center  the
    bounding box on the vertical `baseline'.

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

  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!

    NOTE 3:

      FreeType always shifts the glyph horizontally so that the left
      side bearing is equal to the left side of the bounding box.

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

  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 (`anti-aliasing' is also known as `font-smoothing').

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

    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
      (i.e.,  filled with  zero  bytes) before  the  call.  If  not,
      garbage will accumulate!

    NOTE 4:

      FreeType always shifts the glyph horizontally so that the left
      side bearing is equal to the left side of the bounding box.

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

  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
      are  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.

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

  void  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 given 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.

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

  void  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_Engine       engine,
                         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_Engine       engine,
                         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 (i.e.,
    filled with zero bytes) 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.x) 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.

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

  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 can  be found  in the
    `num_CharMaps'    field   in    the   structure    returned   by
    TT_Get_Face_Property().

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

  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 function.

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

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

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

    Applies a  charMap to  translate `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  (index 0)  is
    returned.

    Note: Since FT 1.5, the  `charCode' is an unsigned long  instead
          of an unsigned short.

    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
    `num_names' minus one; this value  can be found in the structure
    returned by TT_Get_Face_Property().

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

    The platformID is typically in the range [0,3].  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
    zero for `length'.

    NOTE 1:

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

    NOTE 2:

      The library  does not care  about endianess here!  If  you are
      using a  little-endian machine and  you have to  interpret the
      string bytes as 16-bit-wide characters (e.g. Unicode encoded),
      you must byte-swap  the data because 16-bit data  is stored as
      big-endian in TrueType fonts,  and FreeType reads in the whole
      name table bytewise.

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

  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' )

    Use the value 0 instead for `tag' if you want to access the
    whole font file.  `offset' specifies the starting offset in the
    table (or the offset in the file if tag == 0), `buffer' the
    address of target buffer.

    Depending on the value of length, various actions are performed.
    If `length' is NULL, the whole table will be loaded.  An error
    will be returned if `offset' is not 0.  If `*length' is zero,
    TT_Get_Font_Data() exits immediately, returning only the length
    of the given table (in the variable `length'), or of the font
    file, depending on the value of `tag'.  Finally, if `*length' is
    not zero, the next `length' bytes of the table (resp. the font)
    are loaded into an array pointed to by `buffer', starting at
    offset `offset'.  Note that the `buffer' array must be large
    enough to hold `length' bytes.


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



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'.   In  the  following  table,  the  prefix
  `TT_Err_' is omitted, e.g. `Ok' -> `TT_Err_Ok'.


  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 an API function.

  0x0007  Invalid_Argument         An invalid argument was passed to
                                   an 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
                                   while trying to open a file which
                                   isn't a collection.

  0x000A  Table_Missing            The requested TrueType table is
                                   missing in the font file.

  0x000B  Invalid_Horiz_Metrics    The font's HMTX table is invalid.
                                   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 are 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.

  0x0011  Invalid_Vert_Metrics     The font's VMTX table is invalid.
                                   Denotes a broken font.

  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 initialize too many
                                   extensions.  The default max
                                   extensions number is 8 (this
                                   value can be changed at compile
                                   time).

  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.

  0x0030  No_Vertical_Data         There is no vertical data, but
                                   you are requesting it.  Instead,
                                   call TT_Get_Face_Metrics() with
                                   NULL pointers for `topBearings'
                                   and `heights'.

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

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

  0x0082  Horiz_Header_Missing     The horizontal header is missing.
                                   => broken font file

  0x0083  Locations_Missing        The locations table is missing.
                                   => broken font file

  0x0084  Name_Table_Missing       The name table is missing.
                                   => broken font file

  0x0085  CMap_Table_Missing       The character encoding tables are
                                   missing.
                                   => broken font file

  0x0086  Hmtx_Table_Missing       The hmtx table is missing.
                                   => broken font file

  0x0087  OS2_Table_Missing        The OS/2 table is missing.
                                   Some Mac fonts don't have it.

  0x0088  Post_Table_Missing       The PostScript table is missing.
                                   => broken font file

  0x0089  Glyf_Table_Missing       The glyph table is missing.
                                   => broken font file

  ----------------- 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 if more than one
                                   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 are 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()!


--- end of apiref.txt ---
