text: /***************************************************************************/
  /*                                                                         */
  /*  autohint.h                                                             */
  /*                                                                         */
  /*    High-level `autohint' module-specific interface (specification).     */
  /*                                                                         */
  /*  Copyright 1996-2001, 2002, 2007 by                                     */
  /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
  /*                                                                         */
  /*  This file is part of the FreeType project, and may only be used,       */
  /*  modified, and distributed under the terms of the FreeType project      */
  /*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
  /*  this file you indicate that you have read the license and              */
  /*  understand and accept it fully.                                        */
  /*                                                                         */
  /***************************************************************************/
  
  
    /*************************************************************************/
    /*                                                                       */
    /* The auto-hinter is used to load and automatically hint glyphs if a    */
    /* format-specific hinter isn't available.                               */
    /*                                                                       */
    /*************************************************************************/
  
  
  #ifndef __AUTOHINT_H__
  #define __AUTOHINT_H__
  
  
    /*************************************************************************/
    /*                                                                       */
    /* A small technical note regarding automatic hinting in order to        */
    /* clarify this module interface.                                        */
    /*                                                                       */
    /* An automatic hinter might compute two kinds of data for a given face: */
    /*                                                                       */
    /* - global hints: Usually some metrics that describe global properties  */
    /*                 of the face.  It is computed by scanning more or less */
    /*                 aggressively the glyphs in the face, and thus can be  */
    /*                 very slow to compute (even if the size of global      */
    /*                 hints is really small).                               */
    /*                                                                       */
    /* - glyph hints:  These describe some important features of the glyph   */
    /*                 outline, as well as how to align them.  They are      */
    /*                 generally much faster to compute than global hints.   */
    /*                                                                       */
    /* The current FreeType auto-hinter does a pretty good job while         */
    /* performing fast computations for both global and glyph hints.         */
    /* However, we might be interested in introducing more complex and       */
    /* powerful algorithms in the future, like the one described in the John */
    /* D. Hobby paper, which unfortunately requires a lot more horsepower.   */
    /*                                                                       */
    /* Because a sufficiently sophisticated font management system would     */
    /* typically implement an LRU cache of opened face objects to reduce     */
    /* memory usage, it is a good idea to be able to avoid recomputing       */
    /* global hints every time the same face is re-opened.                   */
    /*                                                                       */
    /* We thus provide the ability to cache global hints outside of the face */
    /* object, in order to speed up font re-opening time.  Of course, this   */
    /* feature is purely optional, so most client programs won't even notice */
    /* it.                                                                   */
    /*                                                                       */
    /* I initially thought that it would be a good idea to cache the glyph   */
    /* hints too.  However, my general idea now is that if you really need   */
    /* to cache these too, you are simply in need of a new font format,      */
    /* where all this information could be stored within the font file and   */
    /* decoded on the fly.                                                   */
    /*                                                                       */
    /*************************************************************************/
  
  
  #include <ft2build.h>
  #include FT_FREETYPE_H
  
  
  FT_BEGIN_HEADER
  
  
    typedef struct FT_AutoHinterRec_  *FT_AutoHinter;
  
  
    /*************************************************************************/
    /*                                                                       */
    /* <FuncType>                                                            */
    /*    FT_AutoHinter_GlobalGetFunc                                        */
    /*                                                                       */
    /* <Description>                                                         */
    /*    Retrieves the global hints computed for a given face object the    */
    /*    resulting data is dissociated from the face and will survive a     */
    /*    call to FT_Done_Face().  It must be discarded through the API      */
    /*    FT_AutoHinter_GlobalDoneFunc().                                    */
    /*                                                                       */
    /* <Input>                                                               */
    /*    hinter        :: A handle to the source auto-hinter.               */
    /*                                                                       */
    /*    face          :: A handle to the source face object.               */
    /*                                                                       */
    /* <Output>                                                              */
    /*    global_hints  :: A typeless pointer to the global hints.           */
    /*                                                                       */
    /*    global_len    :: The size in bytes of the global hints.            */
    /*                                                                       */
    typedef void
    (*FT_AutoHinter_GlobalGetFunc)( FT_AutoHinter  hinter,
                                    FT_Face        face,
                                    void**         global_hints,
                                    long*          global_len );
  
  
    /*************************************************************************/
    /*                                                                       */
    /* <FuncType>                                                            */
    /*    FT_AutoHinter_GlobalDoneFunc                                       */
    /*                                                                       */
    /* <Description>                                                         */
    /*    Discards the global hints retrieved through                        */
    /*    FT_AutoHinter_GlobalGetFunc().  This is the only way these hints   */
    /*    are freed from memory.                                             */
    /*                                                                       */
    /* <Input>                                                               */
    /*    hinter :: A handle to the auto-hinter module.                      */
    /*                                                                       */
    /*    global :: A pointer to retrieved global hints to discard.          */
    /*                                                                       */
    typedef void
    (*FT_AutoHinter_GlobalDoneFunc)( FT_AutoHinter  hinter,
                                     void*          global );
  
  
    /*************************************************************************/
    /*                                                                       */
    /* <FuncType>                                                            */
    /*    FT_AutoHinter_GlobalResetFunc                                      */
    /*                                                                       */
    /* <Description>                                                         */
    /*    This function is used to recompute the global metrics in a given   */
    /*    font.  This is useful when global font data changes (e.g. Multiple */
    /*    Masters fonts where blend coordinates change).                     */
    /*                                                                       */
    /* <Input>                                                               */
    /*    hinter :: A handle to the source auto-hinter.                      */
    /*                                                                       */
    /*    face   :: A handle to the face.                                    */
    /*                                                                       */
    typedef void
    (*FT_AutoHinter_GlobalResetFunc)( FT_AutoHinter  hinter,
                                      FT_Face        face );
  
  
    /*************************************************************************/
    /*                                                                       */
    /* <FuncType>                                                            */
    /*    FT_AutoHinter_GlyphLoadFunc                                        */
    /*                                                                       */
    /* <Description>                                                         */
    /*    This function is used to load, scale, and automatically hint a     */
    /*    glyph from a given face.                                           */
    /*                                                                       */
    /* <Input>                                                               */
    /*    face        :: A handle to the face.                               */
    /*                                                                       */
    /*    glyph_index :: The glyph index.                                    */
    /*                                                                       */
    /*    load_flags  :: The load flags.                                     */
    /*                                                                       */
    /* <Note>                                                                */
    /*    This function is capable of loading composite glyphs by hinting    */
    /*    each sub-glyph independently (which improves quality).             */
    /*                                                                       */
    /*    It will call the font driver with FT_Load_Glyph(), with            */
    /*    FT_LOAD_NO_SCALE set.                                              */
    /*                                                                       */
    typedef FT_Error
    (*FT_AutoHinter_GlyphLoadFunc)( FT_AutoHinter  hinter,
                                    FT_GlyphSlot   slot,
                                    FT_Size        size,
                                    FT_UInt        glyph_index,
                                    FT_Int32       load_flags );
  
  
    /*************************************************************************/
    /*                                                                       */
    /* <Struct>                                                              */
    /*    FT_AutoHinter_ServiceRec                                           */
    /*                                                                       */
    /* <Description>                                                         */
    /*    The auto-hinter module's interface.                                */
    /*                                                                       */
    typedef struct  FT_AutoHinter_ServiceRec_
    {
      FT_AutoHinter_GlobalResetFunc  reset_face;
      FT_AutoHinter_GlobalGetFunc    get_global_hints;
      FT_AutoHinter_GlobalDoneFunc   done_global_hints;
      FT_AutoHinter_GlyphLoadFunc    load_glyph;
  
    } FT_AutoHinter_ServiceRec, *FT_AutoHinter_Service;
  
  
  FT_END_HEADER
  
  #endif /* __AUTOHINT_H__ */
  
  
  /* END */
  