ttsbit0.c

奇趣公司比较新的qt/emd版本

        for ( w = width; w >= 8; w -= 8 )
        {
          wval      = (FT_UInt)( wval | *p++ );
          write[0]  = (FT_Byte)( write[0] | ( wval >> x_pos ) );
          write    += 1;
          wval    <<= 8;
        }

        if ( w > 0 )
          wval = (FT_UInt)( wval | ( *p++ & ( 0xFF00U >> w ) ) );

        /* all bits read and there are ( x_pos + w ) bits to be written */

        write[0] = (FT_Byte)( write[0] | ( wval >> x_pos ) );

        if ( x_pos + w > 8 )
        {
          write++;
          wval   <<= 8;
          write[0] = (FT_Byte)( write[0] | ( wval >> x_pos ) );
        }
      }
    }

  Exit:
    return error;
  }


  static FT_Error
  tt_sbit_decoder_load_bit_aligned( TT_SBitDecoder  decoder,
                                    FT_Byte*        p,
                                    FT_Byte*        limit,
                                    FT_Int          x_pos,
                                    FT_Int          y_pos )
  {
    FT_Error    error = SFNT_Err_Ok;
    FT_Byte*    line;
    FT_Int      bit_height, bit_width, pitch, width, height, h, nbits;
    FT_Bitmap*  bitmap;
    FT_UShort   rval;


    if ( !decoder->bitmap_allocated )
    {
      error = tt_sbit_decoder_alloc_bitmap( decoder );
      if ( error )
        goto Exit;
    }

    /* check that we can write the glyph into the bitmap */
    bitmap     = decoder->bitmap;
    bit_width  = bitmap->width;
    bit_height = bitmap->rows;
    pitch      = bitmap->pitch;
    line       = bitmap->buffer;

    width  = decoder->metrics->width;
    height = decoder->metrics->height;

    if ( x_pos < 0 || x_pos + width  > bit_width  ||
         y_pos < 0 || y_pos + height > bit_height )
    {
      error = SFNT_Err_Invalid_File_Format;
      goto Exit;
    }

    if ( p + ( ( width * height + 7 ) >> 3 ) > limit )
    {
      error = SFNT_Err_Invalid_File_Format;
      goto Exit;
    }

    /* now do the blit */
    line  += y_pos * pitch + ( x_pos >> 3 );
    x_pos &= 7;

    /* the higher byte of `rval' is used as a buffer */
    rval  = 0;
    nbits = 0;

    for ( h = height; h > 0; h--, line += pitch )
    {
      FT_Byte*  write = line;
      FT_Int    w = width;


      if ( x_pos )
      {
        w = ( width < 8 - x_pos ) ? width : 8 - x_pos;

        if ( nbits < w )
        {
          rval  |= *p++;
          nbits += 8 - w;
        }
        else
        {
          rval  >>= 8;
          nbits  -= w;
        }

        *write++ |= ( ( rval >> nbits ) & 0xFF ) & ~( 0xFF << w );
        rval    <<= 8;

        w = width - w;
      }

      for ( ; w >= 8; w -= 8 )
      {
        rval     |= *p++;
        *write++ |= ( rval >> nbits ) & 0xFF;

        rval <<= 8;
      }

      if ( w > 0 )
      {
        if ( nbits < w )
        {
          rval   |= *p++;
          *write |= ( ( rval >> nbits ) & 0xFF ) & ( 0xFF00U >> w );
          nbits  += 8 - w;

          rval <<= 8;
        }
        else
        {
          *write |= ( ( rval >> nbits ) & 0xFF ) & ( 0xFF00U >> w );
          nbits  -= w;
        }
      }
    }

  Exit:
    return error;
  }


  static FT_Error
  tt_sbit_decoder_load_compound( TT_SBitDecoder  decoder,
                                 FT_Byte*        p,
                                 FT_Byte*        limit,
                                 FT_Int          x_pos,
                                 FT_Int          y_pos )
  {
    FT_Error  error = SFNT_Err_Ok;
    FT_UInt   num_components, nn;


    if ( p + 2 > limit )
      goto Fail;

    num_components = FT_NEXT_USHORT( p );
    if ( p + 4 * num_components > limit )
      goto Fail;

    for ( nn = 0; nn < num_components; nn++ )
    {
      FT_UInt   gindex = FT_NEXT_USHORT( p );
      FT_Byte   dx     = FT_NEXT_BYTE( p );
      FT_Byte   dy     = FT_NEXT_BYTE( p );


      /* NB: a recursive call */
      error = tt_sbit_decoder_load_image( decoder, gindex,
                                          x_pos + dx, y_pos + dy );
      if ( error )
        break;
    }

  Exit:
    return error;

  Fail:
    error = SFNT_Err_Invalid_File_Format;
    goto Exit;
  }


  static FT_Error
  tt_sbit_decoder_load_bitmap( TT_SBitDecoder  decoder,
                               FT_UInt         glyph_format,
                               FT_ULong        glyph_start,
                               FT_ULong        glyph_size,
                               FT_Int          x_pos,
                               FT_Int          y_pos )
  {
    FT_Error   error;
    FT_Stream  stream = decoder->stream;
    FT_Byte*   p;
    FT_Byte*   p_limit;
    FT_Byte*   data;


    /* seek into the EBDT table now */
    if ( glyph_start + glyph_size > decoder->ebdt_size )
    {
      error = SFNT_Err_Invalid_Argument;
      goto Exit;
    }

    if ( FT_STREAM_SEEK( decoder->ebdt_start + glyph_start ) ||
         FT_FRAME_EXTRACT( glyph_size, data )                )
      goto Exit;

    p       = data;
    p_limit = p + glyph_size;

    /* read the data, depending on the glyph format */
    switch ( glyph_format )
    {
    case 1:
    case 2:
    case 8:
      error = tt_sbit_decoder_load_metrics( decoder, &p, p_limit, 0 );
      break;

    case 6:
    case 7:
    case 9:
      error = tt_sbit_decoder_load_metrics( decoder, &p, p_limit, 1 );
      break;

    default:
      error = SFNT_Err_Ok;
    }

    if ( error )
      goto Fail;

    {
      TT_SBitDecoder_LoadFunc  loader;


      switch ( glyph_format )
      {
      case 1:
      case 6:
        loader = tt_sbit_decoder_load_byte_aligned;
        break;

      case 2:
      case 5:
      case 7:
        loader = tt_sbit_decoder_load_bit_aligned;
        break;

      case 8:
        if ( p + 1 > p_limit )
          goto Fail;

        p += 1;  /* skip padding */
        /* fall-through */

      case 9:
        loader = tt_sbit_decoder_load_compound;
        break;

      default:
        goto Fail;
      }

      error = loader( decoder, p, p_limit, x_pos, y_pos );
    }

  Fail:
    FT_FRAME_RELEASE( data );

  Exit:
    return error;
  }


  static FT_Error
  tt_sbit_decoder_load_image( TT_SBitDecoder  decoder,
                              FT_UInt         glyph_index,
                              FT_Int          x_pos,
                              FT_Int          y_pos )
  {
    /*
     *  First, we find the correct strike range that applies to this
     *  glyph index.
     */

    FT_Byte*  p          = decoder->eblc_base + decoder->strike_index_array;
    FT_Byte*  p_limit    = decoder->eblc_limit;
    FT_ULong  num_ranges = decoder->strike_index_count;
    FT_UInt   start, end, index_format, image_format;
    FT_ULong  image_start = 0, image_end = 0, image_offset;


    if ( p + 8 * num_ranges > p_limit )
      goto NoBitmap;

    for ( ; num_ranges > 0; num_ranges-- )
    {
      start = FT_NEXT_USHORT( p );
      end   = FT_NEXT_USHORT( p );

      if ( glyph_index >= start && glyph_index <= end )
        goto FoundRange;

      p += 4;  /* ignore index offset */
    }
    goto NoBitmap;

  FoundRange:
    image_offset = FT_NEXT_ULONG( p );
    p = decoder->eblc_base + decoder->strike_index_array + image_offset;
    if ( p + 8 > p_limit )
      goto NoBitmap;

    /* now find the glyph's location and extend within the ebdt table */
    index_format = FT_NEXT_USHORT( p );
    image_format = FT_NEXT_USHORT( p );
    image_offset = FT_NEXT_ULONG ( p );

    switch ( index_format )
    {
    case 1: /* 4-byte offsets relative to `image_offset' */
      {
        p += 4 * ( glyph_index - start );
        if ( p + 8 > p_limit )
          goto NoBitmap;

        image_start = FT_NEXT_ULONG( p );
        image_end   = FT_NEXT_ULONG( p );

        if ( image_start == image_end )  /* missing glyph */
          goto NoBitmap;
      }
      break;

    case 2: /* big metrics, constant image size */
      {
        FT_ULong  image_size;


        if ( p + 12 > p_limit )
          goto NoBitmap;

        image_size = FT_NEXT_ULONG( p );

        if ( tt_sbit_decoder_load_metrics( decoder, &p, p_limit, 1 ) )
          goto NoBitmap;

        image_start = image_size * ( glyph_index - start );
        image_end   = image_start  + image_size;
      }
      break;

    case 3: /* 2-byte offsets relative to 'image_offset' */
      {
        p += 2 * ( glyph_index - start );
        if ( p + 4 > p_limit )
          goto NoBitmap;

        image_start = FT_NEXT_USHORT( p );
        image_end   = FT_NEXT_USHORT( p );

        if ( image_start == image_end )  /* missing glyph */
          goto NoBitmap;
      }
      break;

    case 4: /* sparse glyph array with (glyph,offset) pairs */
      {
        FT_ULong  mm, num_glyphs;


        if ( p + 4 > p_limit )
          goto NoBitmap;

        num_glyphs = FT_NEXT_ULONG( p );
        if ( p + ( num_glyphs + 1 ) * 4 > p_limit )
          goto NoBitmap;

        for ( mm = 0; mm < num_glyphs; mm++ )
        {
          FT_UInt  gindex = FT_NEXT_USHORT( p );


          if ( gindex == glyph_index )
          {
            image_start = FT_NEXT_USHORT( p );
            p          += 2;
            image_end   = FT_PEEK_USHORT( p );
            break;
          }
          p += 2;
        }

        if ( mm >= num_glyphs )
          goto NoBitmap;
      }
      break;

    case 5: /* constant metrics with sparse glyph codes */
      {
        FT_ULong  image_size, mm, num_glyphs;


        if ( p + 16 > p_limit )
          goto NoBitmap;

        image_size = FT_NEXT_ULONG( p );

        if ( tt_sbit_decoder_load_metrics( decoder, &p, p_limit, 1 ) )
          goto NoBitmap;

        num_glyphs = FT_NEXT_ULONG( p );
        if ( p + 2 * num_glyphs > p_limit )
          goto NoBitmap;

        for ( mm = 0; mm < num_glyphs; mm++ )
        {
          FT_UInt  gindex = FT_NEXT_USHORT( p );


          if ( gindex == glyph_index )
            break;
        }

        if ( mm >= num_glyphs )
          goto NoBitmap;

        image_start = image_size*mm;
        image_end   = image_start + image_size;
      }
      break;

    default:
      goto NoBitmap;
    }

    if ( image_start > image_end )
      goto NoBitmap;

    image_end  -= image_start;
    image_start = image_offset + image_start;

    return tt_sbit_decoder_load_bitmap( decoder,
                                        image_format,
                                        image_start,
                                        image_end,
                                        x_pos,
                                        y_pos );

  NoBitmap:
    return SFNT_Err_Invalid_Argument;
  }


  FT_LOCAL( FT_Error )
  tt_face_load_sbit_image( TT_Face              face,
                           FT_ULong             strike_index,
                           FT_UInt              glyph_index,
                           FT_UInt              load_flags,
                           FT_Stream            stream,
                           FT_Bitmap           *map,
                           TT_SBit_MetricsRec  *metrics )
  {
    TT_SBitDecoderRec  decoder[1];
    FT_Error           error;

    FT_UNUSED( load_flags );
    FT_UNUSED( stream );
    FT_UNUSED( map );


    error = tt_sbit_decoder_init( decoder, face, strike_index, metrics );
    if ( !error )
    {
      error = tt_sbit_decoder_load_image( decoder, glyph_index, 0, 0 );
      tt_sbit_decoder_done( decoder );
    }

    return error;
  }

/* EOF */