This directory contains several extensions to the core engine.An extension is a separately  compilable unit which can be linked bya client application to add new functionalities to the engine.There  are two  kinds  of extensions:  an  `API extension'  providesclients with new APIs to  access internal engine structures or data,while an  `engine extension' implements  new TrueType data  or tablemanagement.This directory contains the following:  ftxcmap:  An API extension to iterate over cmaps.  ftxgasp:  A simple API extension which returns the TrueType `gasp'            table to client applications, when found in a font file.            Though this table is  always loaded by the engine, there            is no function in the core API to access it.  The reason            is simple:  to demonstrate  a simple API  extension with            `ftxgasp'!  ftxkern:  This engine  extension is  used to access  kerning data,            when available in a  font file.  Note that it implements            on-the-fly  loading and  retrieving  of kerning  tables.            However, it  doesn't interpret or process  the data, and            client  applications  should  use  it according  to  the            TrueType specification.  ftxpost:  An engine  extension to load the  PostScript glyph names            of the  `post' table.   See the `ftzoom'  program for an            example how to use it.  ftxwidth: A simple  extension used to load the  widths and heights            of  a given  range of  glyphs  in a  face.  Results  are            expressed in  unscaled font units.  This  is required by            the  latest version of  the FreeType/2  DLL to  speed up            font loading in the  GRE (the OS/2 GRaphics Engine).  It            can be used by other applications though...  ftxerr18: This extension  simply converts a  TrueType engine error            code into  a corresponding string  describing the error.            It is  useful if you intend  to write a  package for end            users and  want to  give them not  `Error code  135' but            `OS/2  table   missing'.   See  docs/errstr.txt   for  a            description  how to use  it (really  simple!).  ftxerr18            supports localization  of error strings  (that is: error            strings  are  automatically  translated  into  supported            languages)  using  gettext().   See docs/i18n.txt  about            using gettext.  ftxsbit:  Embedded bitmap  support.  This is an engine  extension.            See e.g. the `ftstrtto' program for its usage.  ftxopen,  ftxgsub,  ftxgpos,  ftxgdef:  This is  experimental stuff  for TrueType Open  support!            Please ignore it or help debugging :-)--- END ---