ttdriver.c

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/***************************************************************************/
/*                                                                         */
/*  ttdriver.c                                                             */
/*                                                                         */
/*    TrueType font driver implementation (body).                          */
/*                                                                         */
/*  Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 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.                                        */
/*                                                                         */
/***************************************************************************/


#include <ft2build.h>
#include FT_INTERNAL_DEBUG_H
#include FT_INTERNAL_STREAM_H
#include FT_INTERNAL_SFNT_H
#include FT_TRUETYPE_IDS_H
#include FT_SERVICE_XFREE86_NAME_H

#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
#include FT_MULTIPLE_MASTERS_H
#include FT_SERVICE_MULTIPLE_MASTERS_H
#endif

#include FT_SERVICE_TRUETYPE_ENGINE_H

#include "ttdriver.h"
#include "ttgload.h"

#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
#include "ttgxvar.h"
#endif

#include "tterrors.h"


  /*************************************************************************/
  /*                                                                       */
  /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
  /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
  /* messages during execution.                                            */
  /*                                                                       */
#undef  FT_COMPONENT
#define FT_COMPONENT  trace_ttdriver


  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /****                                                                 ****/
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  /****                          F A C E S                              ****/
  /****                                                                 ****/
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#undef  PAIR_TAG
#define PAIR_TAG( left, right )  ( ( (FT_ULong)left << 16 ) | \
                                     (FT_ULong)right        )


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_get_kerning                                                     */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A driver method used to return the kerning vector between two      */
  /*    glyphs of the same face.                                           */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face        :: A handle to the source face object.                 */
  /*                                                                       */
  /*    left_glyph  :: The index of the left glyph in the kern pair.       */
  /*                                                                       */
  /*    right_glyph :: The index of the right glyph in the kern pair.      */
  /*                                                                       */
  /* <Output>                                                              */
  /*    kerning     :: The kerning vector.  This is in font units for      */
  /*                   scalable formats, and in pixels for fixed-sizes     */
  /*                   formats.                                            */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  /* <Note>                                                                */
  /*    Only horizontal layouts (left-to-right & right-to-left) are        */
  /*    supported by this function.  Other layouts, or more sophisticated  */
  /*    kernings, are out of scope of this method (the basic driver        */
  /*    interface is meant to be simple).                                  */
  /*                                                                       */
  /*    They can be implemented by format-specific interfaces.             */
  /*                                                                       */
  static FT_Error
  tt_get_kerning( FT_Face     ttface,          /* TT_Face */
                  FT_UInt     left_glyph,
                  FT_UInt     right_glyph,
                  FT_Vector*  kerning )
  {
    TT_Face       face = (TT_Face)ttface;
    SFNT_Service  sfnt = (SFNT_Service)face->sfnt;


    kerning->x = 0;
    kerning->y = 0;

    if ( sfnt )
      kerning->x = sfnt->get_kerning( face, left_glyph, right_glyph );

    return 0;
  }


#undef PAIR_TAG


  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /****                                                                 ****/
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  /****                           S I Z E S                             ****/
  /****                                                                 ****/
  /****                                                                 ****/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/


#ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS

  static FT_Error
  tt_size_select( FT_Size   size,
                  FT_ULong  strike_index )
  {
    TT_Face   ttface = (TT_Face)size->face;
    TT_Size   ttsize = (TT_Size)size;
    FT_Error  error  = TT_Err_Ok;


    ttsize->strike_index = strike_index;

    if ( FT_IS_SCALABLE( size->face ) )
    {
      /* use the scaled metrics, even when tt_size_reset fails */
      FT_Select_Metrics( size->face, strike_index );

      tt_size_reset( ttsize );
    }
    else
    {
      SFNT_Service      sfnt    = (SFNT_Service) ttface->sfnt;
      FT_Size_Metrics*  metrics = &size->metrics;


      error = sfnt->load_strike_metrics( ttface, strike_index, metrics );
      if ( error )
        ttsize->strike_index = 0xFFFFFFFFUL;
    }

    return error;
  }

#endif /* TT_CONFIG_OPTION_EMBEDDED_BITMAPS */


  static FT_Error
  tt_size_request( FT_Size          size,
                   FT_Size_Request  req )
  {
    TT_Size   ttsize = (TT_Size)size;
    FT_Error  error  = TT_Err_Ok;


#ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS

    if ( FT_HAS_FIXED_SIZES( size->face ) )
    {
      TT_Face       ttface = (TT_Face)size->face;
      SFNT_Service  sfnt   = (SFNT_Service) ttface->sfnt;
      FT_ULong      strike_index;


      error = sfnt->set_sbit_strike( ttface, req, &strike_index );

      if ( error )
        ttsize->strike_index = 0xFFFFFFFFUL;
      else
        return tt_size_select( size, strike_index );
    }

#endif /* TT_CONFIG_OPTION_EMBEDDED_BITMAPS */

    FT_Request_Metrics( size->face, req );

    if ( FT_IS_SCALABLE( size->face ) )
      error = tt_size_reset( ttsize );