Click here to Skip to main content
15,883,901 members
Articles / Mobile Apps / iPhone

FreeType on OpenGL ES (iPhone)

Rate me:
Please Sign up or sign in to vote.
4.75/5 (10 votes)
24 Nov 2010CPOL4 min read 86.4K   3K   27  
Faster, smarter and better looking fonts rendered with OpenGL ES
/***************************************************************************/
/*                                                                         */
/*  sfdriver.c                                                             */
/*                                                                         */
/*    High-level SFNT driver interface (body).                             */
/*                                                                         */
/*  Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010 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_SFNT_H
#include FT_INTERNAL_OBJECTS_H

#include "sfdriver.h"
#include "ttload.h"
#include "sfobjs.h"
#include "sfntpic.h"

#include "sferrors.h"

#ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS
#include "ttsbit.h"
#endif

#ifdef TT_CONFIG_OPTION_POSTSCRIPT_NAMES
#include "ttpost.h"
#endif

#ifdef TT_CONFIG_OPTION_BDF
#include "ttbdf.h"
#include FT_SERVICE_BDF_H
#endif

#include "ttcmap.h"
#include "ttkern.h"
#include "ttmtx.h"

#include FT_SERVICE_GLYPH_DICT_H
#include FT_SERVICE_POSTSCRIPT_NAME_H
#include FT_SERVICE_SFNT_H
#include FT_SERVICE_TT_CMAP_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_sfdriver


 /*
  *  SFNT TABLE SERVICE
  *
  */

  static void*
  get_sfnt_table( TT_Face      face,
                  FT_Sfnt_Tag  tag )
  {
    void*  table;


    switch ( tag )
    {
    case ft_sfnt_head:
      table = &face->header;
      break;

    case ft_sfnt_hhea:
      table = &face->horizontal;
      break;

    case ft_sfnt_vhea:
      table = face->vertical_info ? &face->vertical : 0;
      break;

    case ft_sfnt_os2:
      table = face->os2.version == 0xFFFFU ? 0 : &face->os2;
      break;

    case ft_sfnt_post:
      table = &face->postscript;
      break;

    case ft_sfnt_maxp:
      table = &face->max_profile;
      break;

    case ft_sfnt_pclt:
      table = face->pclt.Version ? &face->pclt : 0;
      break;

    default:
      table = 0;
    }

    return table;
  }


  static FT_Error
  sfnt_table_info( TT_Face    face,
                   FT_UInt    idx,
                   FT_ULong  *tag,
                   FT_ULong  *offset,
                   FT_ULong  *length )
  {
    if ( !tag || !offset || !length )
      return SFNT_Err_Invalid_Argument;

    if ( idx >= face->num_tables )
      return SFNT_Err_Table_Missing;

    *tag    = face->dir_tables[idx].Tag;
    *offset = face->dir_tables[idx].Offset;
    *length = face->dir_tables[idx].Length;

    return SFNT_Err_Ok;
  }


  FT_DEFINE_SERVICE_SFNT_TABLEREC(sfnt_service_sfnt_table,
    (FT_SFNT_TableLoadFunc)tt_face_load_any,
    (FT_SFNT_TableGetFunc) get_sfnt_table,
    (FT_SFNT_TableInfoFunc)sfnt_table_info
  )


#ifdef TT_CONFIG_OPTION_POSTSCRIPT_NAMES

 /*
  *  GLYPH DICT SERVICE
  *
  */

  static FT_Error
  sfnt_get_glyph_name( TT_Face     face,
                       FT_UInt     glyph_index,
                       FT_Pointer  buffer,
                       FT_UInt     buffer_max )
  {
    FT_String*  gname;
    FT_Error    error;


    error = tt_face_get_ps_name( face, glyph_index, &gname );
    if ( !error )
      FT_STRCPYN( buffer, gname, buffer_max );

    return error;
  }


  static FT_UInt
  sfnt_get_name_index( TT_Face     face,
                       FT_String*  glyph_name )
  {
    FT_Face   root = &face->root;
    FT_UInt   i, max_gid = FT_UINT_MAX;


    if ( root->num_glyphs < 0 )
      return 0;
    else if ( ( FT_ULong ) root->num_glyphs < FT_UINT_MAX )
      max_gid = ( FT_UInt ) root->num_glyphs;
    else
      FT_TRACE0(( "Ignore glyph names for invalid GID 0x%08x - 0x%08x\n",
         FT_UINT_MAX, root->num_glyphs ));

    for ( i = 0; i < max_gid; i++ )
    {
      FT_String*  gname;
      FT_Error    error = tt_face_get_ps_name( face, i, &gname );


      if ( error )
        continue;

      if ( !ft_strcmp( glyph_name, gname ) )
        return i;
    }

    return 0;
  }


  FT_DEFINE_SERVICE_GLYPHDICTREC(sfnt_service_glyph_dict,
    (FT_GlyphDict_GetNameFunc)  sfnt_get_glyph_name,
    (FT_GlyphDict_NameIndexFunc)sfnt_get_name_index
  )

#endif /* TT_CONFIG_OPTION_POSTSCRIPT_NAMES */


 /*
  *  POSTSCRIPT NAME SERVICE
  *
  */

  static const char*
  sfnt_get_ps_name( TT_Face  face )
  {
    FT_Int       n, found_win, found_apple;
    const char*  result = NULL;


    /* shouldn't happen, but just in case to avoid memory leaks */
    if ( face->postscript_name )
      return face->postscript_name;

    /* scan the name table to see whether we have a Postscript name here, */
    /* either in Macintosh or Windows platform encodings                  */
    found_win   = -1;
    found_apple = -1;

    for ( n = 0; n < face->num_names; n++ )
    {
      TT_NameEntryRec*  name = face->name_table.names + n;


      if ( name->nameID == 6 && name->stringLength > 0 )
      {
        if ( name->platformID == 3     &&
             name->encodingID == 1     &&
             name->languageID == 0x409 )
          found_win = n;

        if ( name->platformID == 1 &&
             name->encodingID == 0 &&
             name->languageID == 0 )
          found_apple = n;
      }
    }

    if ( found_win != -1 )
    {
      FT_Memory         memory = face->root.memory;
      TT_NameEntryRec*  name   = face->name_table.names + found_win;
      FT_UInt           len    = name->stringLength / 2;
      FT_Error          error  = SFNT_Err_Ok;

      FT_UNUSED( error );


      if ( !FT_ALLOC( result, name->stringLength + 1 ) )
      {
        FT_Stream   stream = face->name_table.stream;
        FT_String*  r      = (FT_String*)result;
        FT_Byte*    p      = (FT_Byte*)name->string;


        if ( FT_STREAM_SEEK( name->stringOffset ) ||
             FT_FRAME_ENTER( name->stringLength ) )
        {
          FT_FREE( result );
          name->stringLength = 0;
          name->stringOffset = 0;
          FT_FREE( name->string );

          goto Exit;
        }

        p = (FT_Byte*)stream->cursor;

        for ( ; len > 0; len--, p += 2 )
        {
          if ( p[0] == 0 && p[1] >= 32 && p[1] < 128 )
            *r++ = p[1];
        }
        *r = '\0';

        FT_FRAME_EXIT();
      }
      goto Exit;
    }

    if ( found_apple != -1 )
    {
      FT_Memory         memory = face->root.memory;
      TT_NameEntryRec*  name   = face->name_table.names + found_apple;
      FT_UInt           len    = name->stringLength;
      FT_Error          error  = SFNT_Err_Ok;

      FT_UNUSED( error );


      if ( !FT_ALLOC( result, len + 1 ) )
      {
        FT_Stream  stream = face->name_table.stream;


        if ( FT_STREAM_SEEK( name->stringOffset ) ||
             FT_STREAM_READ( result, len )        )
        {
          name->stringOffset = 0;
          name->stringLength = 0;
          FT_FREE( name->string );
          FT_FREE( result );
          goto Exit;
        }
        ((char*)result)[len] = '\0';
      }
    }

  Exit:
    face->postscript_name = result;
    return result;
  }

  FT_DEFINE_SERVICE_PSFONTNAMEREC(sfnt_service_ps_name,
    (FT_PsName_GetFunc)sfnt_get_ps_name
  )


  /*
   *  TT CMAP INFO
   */
  FT_DEFINE_SERVICE_TTCMAPSREC(tt_service_get_cmap_info,
    (TT_CMap_Info_GetFunc)tt_get_cmap_info
  )


#ifdef TT_CONFIG_OPTION_BDF

  static FT_Error
  sfnt_get_charset_id( TT_Face       face,
                       const char*  *acharset_encoding,
                       const char*  *acharset_registry )
  {
    BDF_PropertyRec  encoding, registry;
    FT_Error         error;


    /* XXX: I don't know whether this is correct, since
     *      tt_face_find_bdf_prop only returns something correct if we have
     *      previously selected a size that is listed in the BDF table.
     *      Should we change the BDF table format to include single offsets
     *      for `CHARSET_REGISTRY' and `CHARSET_ENCODING'?
     */
    error = tt_face_find_bdf_prop( face, "CHARSET_REGISTRY", &registry );
    if ( !error )
    {
      error = tt_face_find_bdf_prop( face, "CHARSET_ENCODING", &encoding );
      if ( !error )
      {
        if ( registry.type == BDF_PROPERTY_TYPE_ATOM &&
             encoding.type == BDF_PROPERTY_TYPE_ATOM )
        {
          *acharset_encoding = encoding.u.atom;
          *acharset_registry = registry.u.atom;
        }
        else
          error = SFNT_Err_Invalid_Argument;
      }
    }

    return error;
  }


  FT_DEFINE_SERVICE_BDFRec(sfnt_service_bdf,
    (FT_BDF_GetCharsetIdFunc) sfnt_get_charset_id,
    (FT_BDF_GetPropertyFunc)  tt_face_find_bdf_prop
  )

#endif /* TT_CONFIG_OPTION_BDF */


  /*
   *  SERVICE LIST
   */

#if defined TT_CONFIG_OPTION_POSTSCRIPT_NAMES && defined TT_CONFIG_OPTION_BDF
  FT_DEFINE_SERVICEDESCREC5(sfnt_services,
    FT_SERVICE_ID_SFNT_TABLE,           &FT_SFNT_SERVICE_SFNT_TABLE_GET,
    FT_SERVICE_ID_POSTSCRIPT_FONT_NAME, &FT_SFNT_SERVICE_PS_NAME_GET,
    FT_SERVICE_ID_GLYPH_DICT,           &FT_SFNT_SERVICE_GLYPH_DICT_GET,
    FT_SERVICE_ID_BDF,                  &FT_SFNT_SERVICE_BDF_GET,
    FT_SERVICE_ID_TT_CMAP,              &FT_TT_SERVICE_GET_CMAP_INFO_GET
  )
#elif defined TT_CONFIG_OPTION_POSTSCRIPT_NAMES
  FT_DEFINE_SERVICEDESCREC4(sfnt_services,
    FT_SERVICE_ID_SFNT_TABLE,           &FT_SFNT_SERVICE_SFNT_TABLE_GET,
    FT_SERVICE_ID_POSTSCRIPT_FONT_NAME, &FT_SFNT_SERVICE_PS_NAME_GET,
    FT_SERVICE_ID_GLYPH_DICT,           &FT_SFNT_SERVICE_GLYPH_DICT_GET,
    FT_SERVICE_ID_TT_CMAP,              &FT_TT_SERVICE_GET_CMAP_INFO_GET
  )
#elif defined TT_CONFIG_OPTION_BDF
  FT_DEFINE_SERVICEDESCREC4(sfnt_services,
    FT_SERVICE_ID_SFNT_TABLE,           &FT_SFNT_SERVICE_SFNT_TABLE_GET,
    FT_SERVICE_ID_POSTSCRIPT_FONT_NAME, &FT_SFNT_SERVICE_PS_NAME_GET,
    FT_SERVICE_ID_BDF,                  &FT_SFNT_SERVICE_BDF_GET,
    FT_SERVICE_ID_TT_CMAP,              &FT_TT_SERVICE_GET_CMAP_INFO_GET
  )
#else
  FT_DEFINE_SERVICEDESCREC3(sfnt_services,
    FT_SERVICE_ID_SFNT_TABLE,           &FT_SFNT_SERVICE_SFNT_TABLE_GET,
    FT_SERVICE_ID_POSTSCRIPT_FONT_NAME, &FT_SFNT_SERVICE_PS_NAME_GET,
    FT_SERVICE_ID_TT_CMAP,              &FT_TT_SERVICE_GET_CMAP_INFO_GET
  )
#endif


  FT_CALLBACK_DEF( FT_Module_Interface )
  sfnt_get_interface( FT_Module    module,
                      const char*  module_interface )
  {
    FT_UNUSED( module );

    return ft_service_list_lookup( FT_SFNT_SERVICES_GET, module_interface );
  }


#ifdef FT_CONFIG_OPTION_OLD_INTERNALS

  FT_CALLBACK_DEF( FT_Error )
  tt_face_load_sfnt_header_stub( TT_Face      face,
                                 FT_Stream    stream,
                                 FT_Long      face_index,
                                 SFNT_Header  header )
  {
    FT_UNUSED( face );
    FT_UNUSED( stream );
    FT_UNUSED( face_index );
    FT_UNUSED( header );

    return SFNT_Err_Unimplemented_Feature;
  }


  FT_CALLBACK_DEF( FT_Error )
  tt_face_load_directory_stub( TT_Face      face,
                               FT_Stream    stream,
                               SFNT_Header  header )
  {
    FT_UNUSED( face );
    FT_UNUSED( stream );
    FT_UNUSED( header );

    return SFNT_Err_Unimplemented_Feature;
  }


  FT_CALLBACK_DEF( FT_Error )
  tt_face_load_hdmx_stub( TT_Face    face,
                          FT_Stream  stream )
  {
    FT_UNUSED( face );
    FT_UNUSED( stream );

    return SFNT_Err_Unimplemented_Feature;
  }


  FT_CALLBACK_DEF( void )
  tt_face_free_hdmx_stub( TT_Face  face )
  {
    FT_UNUSED( face );
  }


  FT_CALLBACK_DEF( FT_Error )
  tt_face_set_sbit_strike_stub( TT_Face    face,
                                FT_UInt    x_ppem,
                                FT_UInt    y_ppem,
                                FT_ULong*  astrike_index )
  {
    /*
     * We simply forge a FT_Size_Request and call the real function
     * that does all the work.
     *
     * This stub might be called by libXfont in the X.Org Xserver,
     * compiled against version 2.1.8 or newer.
     */

    FT_Size_RequestRec  req;


    req.type           = FT_SIZE_REQUEST_TYPE_NOMINAL;
    req.width          = (FT_F26Dot6)x_ppem;
    req.height         = (FT_F26Dot6)y_ppem;
    req.horiResolution = 0;
    req.vertResolution = 0;

    *astrike_index = 0x7FFFFFFFUL;

    return tt_face_set_sbit_strike( face, &req, astrike_index );
  }


  FT_CALLBACK_DEF( FT_Error )
  tt_face_load_sbit_stub( TT_Face    face,
                          FT_Stream  stream )
  {
    FT_UNUSED( face );
    FT_UNUSED( stream );

    /*
     *  This function was originally implemented to load the sbit table.
     *  However, it has been replaced by `tt_face_load_eblc', and this stub
     *  is only there for some rogue clients which would want to call it
     *  directly (which doesn't make much sense).
     */
    return SFNT_Err_Unimplemented_Feature;
  }


  FT_CALLBACK_DEF( void )
  tt_face_free_sbit_stub( TT_Face  face )
  {
    /* nothing to do in this stub */
    FT_UNUSED( face );
  }


  FT_CALLBACK_DEF( FT_Error )
  tt_face_load_charmap_stub( TT_Face    face,
                             void*      cmap,
                             FT_Stream  input )
  {
    FT_UNUSED( face );
    FT_UNUSED( cmap );
    FT_UNUSED( input );

    return SFNT_Err_Unimplemented_Feature;
  }


  FT_CALLBACK_DEF( FT_Error )
  tt_face_free_charmap_stub( TT_Face  face,
                             void*    cmap )
  {
    FT_UNUSED( face );
    FT_UNUSED( cmap );

    return SFNT_Err_Ok;
  }

#endif /* FT_CONFIG_OPTION_OLD_INTERNALS */

#ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS
#define PUT_EMBEDDED_BITMAPS(a) a 
#else
#define PUT_EMBEDDED_BITMAPS(a) 0 
#endif
#ifdef TT_CONFIG_OPTION_POSTSCRIPT_NAMES
#define PUT_PS_NAMES(a) a 
#else
#define PUT_PS_NAMES(a) 0 
#endif

  FT_DEFINE_SFNT_INTERFACE(sfnt_interface,
    tt_face_goto_table,

    sfnt_init_face,
    sfnt_load_face,
    sfnt_done_face,
    sfnt_get_interface,

    tt_face_load_any,

    tt_face_load_sfnt_header_stub, /* FT_CONFIG_OPTION_OLD_INTERNALS */
    tt_face_load_directory_stub, /* FT_CONFIG_OPTION_OLD_INTERNALS */

    tt_face_load_head,
    tt_face_load_hhea,
    tt_face_load_cmap,
    tt_face_load_maxp,
    tt_face_load_os2,
    tt_face_load_post,

    tt_face_load_name,
    tt_face_free_name,

    tt_face_load_hdmx_stub, /* FT_CONFIG_OPTION_OLD_INTERNALS */
    tt_face_free_hdmx_stub, /* FT_CONFIG_OPTION_OLD_INTERNALS */

    tt_face_load_kern,
    tt_face_load_gasp,
    tt_face_load_pclt,

    /* see `ttload.h' */
    PUT_EMBEDDED_BITMAPS(tt_face_load_bhed),

    tt_face_set_sbit_strike_stub, /* FT_CONFIG_OPTION_OLD_INTERNALS */
    tt_face_load_sbit_stub, /* FT_CONFIG_OPTION_OLD_INTERNALS */

    tt_find_sbit_image, /* FT_CONFIG_OPTION_OLD_INTERNALS */
    tt_load_sbit_metrics, /* FT_CONFIG_OPTION_OLD_INTERNALS */

    PUT_EMBEDDED_BITMAPS(tt_face_load_sbit_image),

    tt_face_free_sbit_stub, /* FT_CONFIG_OPTION_OLD_INTERNALS */

    /* see `ttpost.h' */
    PUT_PS_NAMES(tt_face_get_ps_name),
    PUT_PS_NAMES(tt_face_free_ps_names),

    tt_face_load_charmap_stub, /* FT_CONFIG_OPTION_OLD_INTERNALS */
    tt_face_free_charmap_stub, /* FT_CONFIG_OPTION_OLD_INTERNALS */

    /* since version 2.1.8 */

    tt_face_get_kerning,

    /* since version 2.2 */

    tt_face_load_font_dir,
    tt_face_load_hmtx,

    /* see `ttsbit.h' and `sfnt.h' */
    PUT_EMBEDDED_BITMAPS(tt_face_load_eblc),
    PUT_EMBEDDED_BITMAPS(tt_face_free_eblc),

    PUT_EMBEDDED_BITMAPS(tt_face_set_sbit_strike),
    PUT_EMBEDDED_BITMAPS(tt_face_load_strike_metrics),

    tt_face_get_metrics
  )


  FT_DEFINE_MODULE(sfnt_module_class,
  
    0,  /* not a font driver or renderer */
    sizeof( FT_ModuleRec ),

    "sfnt",     /* driver name                            */
    0x10000L,   /* driver version 1.0                     */
    0x20000L,   /* driver requires FreeType 2.0 or higher */

    (const void*)&FT_SFNT_INTERFACE_GET,  /* module specific interface */

    (FT_Module_Constructor)0,
    (FT_Module_Destructor) 0,
    (FT_Module_Requester)  sfnt_get_interface
  )


/* END */

By viewing downloads associated with this article you agree to the Terms of Service and the article's licence.

If a file you wish to view isn't highlighted, and is a text file (not binary), please let us know and we'll add colourisation support for it.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


Written By
Software Developer Astronautz
Spain Spain
After working in the software industry for many years, I've started my own games company that specialises in strategy games for mobile platforms.

Comments and Discussions