path: root/src/gf/gfdrivr.c

/****************************************************************************
 *
 * gfdrivr.c
 *
 *   FreeType font driver for METAFONT GF FONT files
 *
 * Copyright 1996-2018 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_OBJECTS_H
#include FT_TRUETYPE_IDS_H
#include FT_INTERNAL_TFM_H

#include FT_SERVICE_GF_H
#include FT_SERVICE_FONT_FORMAT_H

#include "gf.h"
#include "gfdrivr.h"
#include "gferror.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_gfdriver


  typedef struct  GF_CMapRec_
  {
    FT_CMapRec      cmap;
    FT_ULong        num_encodings;
    GF_Encoding     encodings;
  } GF_CMapRec, *GF_CMap;


  FT_CALLBACK_DEF( FT_Error )
  gf_cmap_init(  FT_CMap     gfcmap,
                 FT_Pointer  init_data )
  {
    GF_CMap  cmap = (GF_CMap) gfcmap;
    GF_Face  face = (GF_Face) FT_CMAP_FACE( cmap );
    FT_UNUSED( init_data );

    cmap->num_encodings = face->gf_glyph->nencodings;
    cmap->encodings     = face->gf_glyph->encodings;

    return FT_Err_Ok;
  }


  FT_CALLBACK_DEF( void )
  gf_cmap_done( FT_CMap  gfcmap )
  {
    GF_CMap  cmap = (GF_CMap) gfcmap;

    cmap->encodings     = NULL;
    cmap->num_encodings = 0;

  }


  FT_CALLBACK_DEF( FT_UInt )
  gf_cmap_char_index(  FT_CMap    gfcmap,
                       FT_UInt32  charcode )
  {
    GF_CMap       cmap      = (GF_CMap) gfcmap;
    GF_Encoding   encodings = cmap->encodings;
    FT_UInt       max, code, result = 0, i;

    max = cmap->num_encodings;

    for( i = 0; i < max; i++ )
    {
      code = (FT_ULong) encodings[i].enc;
      if ( charcode == code )
      {
        result = encodings[i].glyph;
        goto Exit;
      }
    }
  Exit:
    return result;
  }


  FT_CALLBACK_DEF( FT_UInt )
  gf_cmap_char_next(  FT_CMap     gfcmap,
                      FT_UInt32  *acharcode )
  {
    GF_CMap       cmap      = (GF_CMap) gfcmap;
    GF_Encoding   encodings = cmap->encodings;
    FT_UInt       result    = 0, i, code, max;
    FT_ULong      charcode  = *acharcode + 1;

    max = cmap->num_encodings;

    for( i = 0; i < max; i++ )
    {
      code = (FT_ULong) encodings[i].enc;
      if ( charcode == code )
      {
        result = encodings[i].glyph + 1;
        goto Exit;
      }
    }

  Exit:
    if ( charcode > 0xFFFFFFFFUL )
    {
      FT_TRACE1(( "gf_cmap_char_next: charcode 0x%x > 32bit API" ));
      *acharcode = 0;
      /* XXX: result should be changed to indicate an overflow error */
    }
    else
      *acharcode = (FT_UInt32) charcode;
    return result;
  }


  static
  const FT_CMap_ClassRec  gf_cmap_class =
  {
    sizeof ( GF_CMapRec ),
    gf_cmap_init,
    gf_cmap_done,
    gf_cmap_char_index,
    gf_cmap_char_next,

    NULL, NULL, NULL, NULL, NULL
  };


  FT_CALLBACK_DEF( void )
  GF_Face_Done( FT_Face  gfface )         /* GF_Face */
  {
    GF_Face    face = (GF_Face) gfface;
    FT_Memory  memory;

    if ( !face )
      return;

    memory = FT_FACE_MEMORY( face );

    FT_FREE( gfface->available_sizes );

    if( face->gf_glyph )
      FT_FREE( face->gf_glyph->encodings );

    gf_free_font( face );

  }


  FT_CALLBACK_DEF( FT_Error )
  GF_Face_Init(  FT_Stream     stream,
                 FT_Face       gfface,     /* GF_Face */
                 FT_Int        face_index,
                 FT_Int        num_params,
                 FT_Parameter* params )
  {
    GF_Face     face   = (GF_Face) gfface;
    FT_Error    error  = FT_Err_Ok;
    FT_Memory   memory = FT_FACE_MEMORY( face );
    GF_Glyph    go     = NULL;

    TFM_Service tfm;

    FT_UNUSED( num_params );
    FT_UNUSED( params );


    face->tfm = FT_Get_Module_Interface( FT_FACE_LIBRARY( face ), "tfm" );

    tfm = (TFM_Service) face->tfm;
    if ( !tfm )
    {
      FT_ERROR(( "GF_Face_Init: cannot access `tfm' module\n" ));
      error = FT_THROW( Missing_Module );
      goto Exit;
    }

    FT_TRACE2(( "GF driver\n" ));

    /* load font */
    error = gf_load_font( stream, memory, &go );
    if ( FT_ERR_EQ( error, Unknown_File_Format ) )
    {
      FT_TRACE2(( "  not a GF file\n" ));
      goto Fail;
    }
    else if ( error )
      goto Exit;

    /* we have a gf font: let's construct the face object */
    face->gf_glyph = go;

    /* sanity check */
    if ( !face->gf_glyph->bm_table )
    {
      FT_TRACE2(( "glyph bitmaps not allocated\n" ));
      error = FT_THROW( Invalid_File_Format );
      goto Exit;
    }

    /* GF cannot have multiple faces in a single font file.
     * XXX: non-zero face_index is already invalid argument, but
     *      Type1, Type42 driver has a convention to return
     *      an invalid argument error when the font could be
     *      opened by the specified driver.
     */
    if ( face_index > 0 && ( face_index & 0xFFFF ) > 0 )
    {
      FT_ERROR(( "GF_Face_Init: invalid face index\n" ));
      GF_Face_Done( gfface );
      return FT_THROW( Invalid_Argument );
    }

    /* we now need to fill the root FT_Face fields */
    /* with relevant information                   */

    gfface->num_faces       = 1;
    gfface->face_index      = 0;
    gfface->face_flags     |= FT_FACE_FLAG_FIXED_SIZES |
                             FT_FACE_FLAG_HORIZONTAL ;
    /*
     * XXX: TO-DO: gfface->face_flags |= FT_FACE_FLAG_FIXED_WIDTH;
     * XXX: I have to check for this.
     */

    gfface->family_name     = NULL;
    gfface->num_glyphs      = (FT_Long) go->nglyphs;

    FT_TRACE4(( "  number of glyphs: allocated %d\n", gfface->num_glyphs ));

    if ( gfface->num_glyphs <= 0 )
    {
      FT_ERROR(( "GF_Face_Init: glyphs not allocated\n" ));
      error = FT_THROW( Invalid_File_Format );
      goto Exit;
    }

    gfface->num_fixed_sizes = 1;
    if ( FT_NEW_ARRAY( gfface->available_sizes, 1 ) )
      goto Exit;

    {
      FT_Bitmap_Size*  bsize = gfface->available_sizes;
      FT_UShort        x_res, y_res;

      bsize->height = (FT_Short) face->gf_glyph->font_bbx_h ;
      bsize->width  = (FT_Short) face->gf_glyph->font_bbx_w ;
      bsize->size   = (FT_Pos)   FT_MulDiv( FT_ABS( face->gf_glyph->ds ),
                                                    64 * 7200,
                                                    72270L );
      x_res = toint( go->hppp * 72.27 );
      y_res = toint( go->vppp * 72.27 );

      bsize->y_ppem = (FT_Pos) toint((face->gf_glyph->ds * y_res)/ 72.27) << 6 ;
      bsize->x_ppem = (FT_Pos) FT_MulDiv( bsize->y_ppem,
                                          x_res,
                                          y_res );
    }

    /* set up charmap */
    {
      /* FT_Bool     unicode_charmap ; */

      /*
       * XXX: TO-DO
       * Currently the unicode_charmap is set to `0'
       * The functionality of extracting coding scheme
       * from `xxx' and `yyy' commands will be used to
       * set the unicode_charmap.
      */
    }

    /* Charmaps */
    {
      FT_CharMapRec  charmap;
      FT_Bool        unicode_charmap = 0;

      charmap.face        = FT_FACE( face );
      charmap.encoding    = FT_ENCODING_NONE;
      charmap.platform_id = TT_PLATFORM_APPLE_UNICODE;
      charmap.encoding_id = TT_APPLE_ID_DEFAULT;

      if( unicode_charmap )
      {
        /* Unicode Charmap */
        charmap.encoding    = FT_ENCODING_UNICODE;
        charmap.platform_id = TT_PLATFORM_MICROSOFT;
        charmap.encoding_id = TT_MS_ID_UNICODE_CS;
      }

      error = FT_CMap_New( &gf_cmap_class, NULL, &charmap, NULL );

      if ( error )
        goto Exit;
    }

    if ( go->code_max < go->code_min )
    {
      FT_TRACE2(( "invalid number of glyphs\n" ));
      error = FT_THROW( Invalid_File_Format );
      goto Exit;
    }

  Exit:
    return error;

  Fail:
    GF_Face_Done( gfface );
    return FT_THROW( Unknown_File_Format );
  }


  FT_CALLBACK_DEF( FT_Error )
  GF_Size_Select(  FT_Size   size,
                   FT_ULong  strike_index )
  {
    GF_Face     face  = (GF_Face)size->face;
    GF_Glyph    go    = face->gf_glyph;
    FT_UNUSED( strike_index );

    FT_Select_Metrics( size->face, 0 );

    size->metrics.ascender    = ( go->font_bbx_h - go->font_bbx_yoff ) * 64;
    size->metrics.descender   = -go->font_bbx_yoff * 64;
    size->metrics.max_advance = go->font_bbx_w * 64;

    return FT_Err_Ok;

  }


  FT_CALLBACK_DEF( FT_Error )
  GF_Size_Request(  FT_Size          size,
                    FT_Size_Request  req )
  {
    GF_Face           face    = (GF_Face) size->face;
    FT_Bitmap_Size*   bsize   = size->face->available_sizes;
    FT_Error          error   = FT_ERR( Invalid_Pixel_Size );
    FT_Long           height;


    height = FT_REQUEST_HEIGHT( req );
    height = ( height + 32 ) >> 6;

    switch ( req->type )
    {
    case FT_SIZE_REQUEST_TYPE_NOMINAL:
      if ( height == ( ( bsize->y_ppem + 32 ) >> 6 ) )
        error = FT_Err_Ok;
      break;

    case FT_SIZE_REQUEST_TYPE_REAL_DIM:
      if ( height == face->gf_glyph->font_bbx_h )
        error = FT_Err_Ok;
      break;

    default:
      error = FT_THROW( Unimplemented_Feature );
      break;
    }

    if ( error )
      return error;
    else
      return GF_Size_Select( size, 0 );
  }


  FT_CALLBACK_DEF( FT_Error )
  GF_Glyph_Load(  FT_GlyphSlot  slot,
                  FT_Size       size,
                  FT_UInt       glyph_index,
                  FT_Int32      load_flags )
  {
    GF_Face      gf     = (GF_Face) FT_SIZE_FACE( size );
    FT_Face      face   = FT_FACE ( gf );
    FT_Error     error  = FT_Err_Ok;
    FT_Bitmap*   bitmap = &slot->bitmap;
    GF_Bitmap    bm;
    GF_Glyph     go;

    go = gf->gf_glyph;

    FT_UNUSED( load_flags );

    if ( !face )
    {
      error = FT_THROW( Invalid_Face_Handle );
      goto Exit;
    }

    if ( !go                                         ||
         glyph_index >= (FT_UInt)( face->num_glyphs ) )
    {
      error = FT_THROW( Invalid_Argument );
      goto Exit;
    }

    FT_TRACE1(( "GF_Glyph_Load: glyph index %d charcode is %d\n",
		 glyph_index, go->bm_table[glyph_index].code ));

    if ( !go->bm_table )
    {
      FT_TRACE2(( "invalid bitmap table\n" ));
      error = FT_THROW( Invalid_File_Format );
      goto Exit;
    }

    /* slot, bitmap => freetype, bm => gflib */
    bm = &gf->gf_glyph->bm_table[glyph_index];

    bitmap->rows       = bm->bbx_height;
    bitmap->width      = bm->bbx_width;
    bitmap->pixel_mode = FT_PIXEL_MODE_MONO;

    if ( !bm->raster )
    {
      FT_TRACE2(( "invalid bitmap width\n" ));
      error = FT_THROW( Invalid_File_Format );
      goto Exit;
    }

    bitmap->pitch = (FT_Int) bm->raster ;

    /* note: we don't allocate a new array to hold the bitmap; */
    /*       we can simply point to it                         */
    ft_glyphslot_set_bitmap( slot, bm->bitmap );

    slot->format      = FT_GLYPH_FORMAT_BITMAP;
    slot->bitmap_left = bm->off_x ;
    slot->bitmap_top  = bm->off_y ;

    slot->metrics.horiAdvance  = (FT_Pos) (bm->mv_x ) * 64;
    slot->metrics.horiBearingX = (FT_Pos) (bm->off_x ) * 64;
    slot->metrics.horiBearingY = (FT_Pos) (bm->bbx_height) * 64;
    slot->metrics.width        = (FT_Pos) ( bitmap->width * 64 );
    slot->metrics.height       = (FT_Pos) ( bitmap->rows * 64 );

    FT_TRACE2(( "Glyph metric values are: bm->bbx_height is %ld\n"
                "                         bm->bbx_width  is %ld\n"
                "                         bm->off_x      is %ld\n"
                "                         bm->off_y      is %ld\n"
                "                         bm->mv_x       is %ld\n"
                "                         bm->mv_y       is %ld\n",
		bm->bbx_height, bm->bbx_width, bm->off_x, bm->off_y,
		bm->mv_x, bm->mv_y ));

    ft_synthesize_vertical_metrics( &slot->metrics, bm->bbx_height * 64 );

  Exit:
    return error;
  }


  FT_LOCAL_DEF( void )
  TFM_Done_Metrics( FT_Memory     memory,
                    TFM_FontInfo  fi )
  {
    FT_FREE( fi->width );
    FT_FREE( fi->height );
    FT_FREE( fi->depth );
    FT_FREE( fi );
  }


  /* parse a TFM metrics file */
  FT_LOCAL_DEF( FT_Error )
  TFM_Read_Metrics( FT_Face    gf_face,
                    FT_Stream  stream )
  {
    TFM_Service    tfm;
    FT_Memory      memory  = stream->memory;
    TFM_ParserRec  parser;
    TFM_FontInfo   fi      = NULL;
    FT_Error       error   = FT_ERR( Unknown_File_Format );
    GF_Face        face    = (GF_Face) gf_face;
    GF_Glyph       gf_glyph= face->gf_glyph;


    if ( face->tfm_data )
    {
      FT_TRACE1(( "TFM_Read_Metrics:"
                  "Freeing previously attached metrics data.\n" ));
      TFM_Done_Metrics( memory, (TFM_FontInfo)face->tfm_data );

      face->tfm_data = NULL;
    }

    if ( FT_NEW( fi ) )
      goto Exit;

    FT_TRACE4(( "TFM_Read_Metrics: Invoking TFM_Service.\n" ));

    tfm = (TFM_Service)face->tfm;
    if ( tfm->tfm_parser_funcs )
    {
      /* Initialise TFM Service */
      error = tfm->tfm_parser_funcs->init( &parser,
                                           memory,
                                           stream );
      if ( !error )
      {
        FT_TRACE4(( "TFM_Read_Metrics: Initialised tfm metric data.\n" ));

        parser.FontInfo  = fi;
        parser.user_data = gf_glyph;

        error = tfm->tfm_parser_funcs->parse_metrics( &parser );

	if( !error )
          FT_TRACE4(( "TFM_Read_Metrics: parsing TFM metric information done.\n" ));

        FT_TRACE6(( "TFM_Read_Metrics: TFM Metric Information:\n"
                    "                  Check Sum  : %ld\n"
                    "                  Design Size: %ld\n"
                    "                  Begin Char : %d\n"
                    "                  End Char   : %d\n"
                    "                  font_bbx_w : %d\n"
                    "                  font_bbx_h : %d\n"
                    "                  slant      : %d\n",
		    parser.FontInfo->cs, parser.FontInfo->design_size,
		    parser.FontInfo->begin_char, parser.FontInfo->end_char,
		    parser.FontInfo->font_bbx_w, parser.FontInfo->font_bbx_h,
		    parser.FontInfo->slant ));

	tfm->tfm_parser_funcs->done( &parser );
      }
    }

    if ( !error )
    {
      /* Modify GF_Glyph data according to TFM metric values */

      /*
      face->gf_glyph->font_bbx_w = fi->font_bbx_w;
      face->gf_glyph->font_bbx_h = fi->font_bbx_h;
      */

      face->tfm_data       = fi;
    }

  Exit:
    if ( fi )
      TFM_Done_Metrics( memory, fi );

    return error;
  }


 /*
  *
  * SERVICES LIST
  *
  */

  static const FT_ServiceDescRec  gf_services[] =
  {
    { FT_SERVICE_ID_GF,          NULL },
    { FT_SERVICE_ID_FONT_FORMAT, FT_FONT_FORMAT_GF },
    { NULL, NULL }
  };


  FT_CALLBACK_DEF( FT_Module_Interface )
  gf_driver_requester( FT_Module    module,
                       const char*  name )
  {
    FT_UNUSED( module );

    return ft_service_list_lookup( gf_services, name );
  }


  FT_CALLBACK_TABLE_DEF
  const FT_Driver_ClassRec  gf_driver_class =
  {
    {
      FT_MODULE_FONT_DRIVER         |
      FT_MODULE_DRIVER_NO_OUTLINES,
      sizeof ( FT_DriverRec ),

      "gf",
      0x10000L,
      0x20000L,

      NULL,    			/* module-specific interface */

      NULL,                     /* FT_Module_Constructor  module_init   */
      NULL,                     /* FT_Module_Destructor   module_done   */
      gf_driver_requester     	/* FT_Module_Requester    get_interface */
    },

    sizeof ( GF_FaceRec ),
    sizeof ( FT_SizeRec ),
    sizeof ( FT_GlyphSlotRec ),

    GF_Face_Init,               /* FT_Face_InitFunc  init_face */
    GF_Face_Done,               /* FT_Face_DoneFunc  done_face */
    NULL,                       /* FT_Size_InitFunc  init_size */
    NULL,                       /* FT_Size_DoneFunc  done_size */
    NULL,                       /* FT_Slot_InitFunc  init_slot */
    NULL,                       /* FT_Slot_DoneFunc  done_slot */

    GF_Glyph_Load,              /* FT_Slot_LoadFunc  load_glyph */

    NULL,                       /* FT_Face_GetKerningFunc   get_kerning  */
    TFM_Read_Metrics,           /* FT_Face_AttachFunc       attach_file  */
    NULL,                       /* FT_Face_GetAdvancesFunc  get_advances */

    GF_Size_Request,            /* FT_Size_RequestFunc  request_size */
    GF_Size_Select              /* FT_Size_SelectFunc   select_size  */
  };


/* END */