ttsbit.c

奇趣公司比较新的qt/emd版本

            {
              if ( (FT_UInt)range->glyph_codes[n] == glyph_index )
              {
                if ( range->index_format == 4 )
                  *aglyph_offset = range->glyph_offsets[n];
                else
                  *aglyph_offset = range->image_offset +
                                   n * range->image_size;
                goto Found;
              }
            }
          }

        /* fall-through */
        default:
          goto Fail;
        }

      Found:
        /* return successfully! */
        *arange  = range;
        return 0;
      }
    }

  Fail:
    *arange        = 0;
    *aglyph_offset = 0;

    return SFNT_Err_Invalid_Argument;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_find_sbit_image                                                 */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Checks whether an embedded bitmap (an `sbit') exists for a given   */
  /*    glyph, at a given strike.                                          */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face          :: The target face object.                           */
  /*                                                                       */
  /*    glyph_index   :: The glyph index.                                  */
  /*                                                                       */
  /*    strike_index  :: The current strike index.                         */
  /*                                                                       */
  /* <Output>                                                              */
  /*    arange        :: The SBit range containing the glyph index.        */
  /*                                                                       */
  /*    astrike       :: The SBit strike containing the glyph index.       */
  /*                                                                       */
  /*    aglyph_offset :: The offset of the glyph data in `EBDT' table.     */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.  Returns                    */
  /*    SFNT_Err_Invalid_Argument if no sbit exists for the requested      */
  /*    glyph.                                                             */
  /*                                                                       */
  FT_LOCAL( FT_Error )
  tt_find_sbit_image( TT_Face          face,
                      FT_UInt          glyph_index,
                      FT_ULong         strike_index,
                      TT_SBit_Range   *arange,
                      TT_SBit_Strike  *astrike,
                      FT_ULong        *aglyph_offset )
  {
    FT_Error        error;
    TT_SBit_Strike  strike;


    if ( !face->sbit_strikes                        ||
         ( face->num_sbit_strikes <= strike_index ) )
      goto Fail;

    strike = &face->sbit_strikes[strike_index];

    error = find_sbit_range( glyph_index, strike,
                             arange, aglyph_offset );
    if ( error )
      goto Fail;

    *astrike = strike;

    return SFNT_Err_Ok;

  Fail:
    /* no embedded bitmap for this glyph in face */
    *arange        = 0;
    *astrike       = 0;
    *aglyph_offset = 0;

    return SFNT_Err_Invalid_Argument;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_load_sbit_metrics                                               */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Gets the big metrics for a given SBit.                             */
  /*                                                                       */
  /* <Input>                                                               */
  /*    stream      :: The input stream.                                   */
  /*                                                                       */
  /*    range       :: The SBit range containing the glyph.                */
  /*                                                                       */
  /* <Output>                                                              */
  /*    big_metrics :: A big SBit metrics structure for the glyph.         */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  /* <Note>                                                                */
  /*    The stream cursor must be positioned at the glyph's offset within  */
  /*    the `EBDT' table before the call.                                  */
  /*                                                                       */
  /*    If the image format uses variable metrics, the stream cursor is    */
  /*    positioned just after the metrics header in the `EBDT' table on    */
  /*    function exit.                                                     */
  /*                                                                       */
  FT_LOCAL( FT_Error )
  tt_load_sbit_metrics( FT_Stream        stream,
                        TT_SBit_Range    range,
                        TT_SBit_Metrics  metrics )
  {
    FT_Error  error = SFNT_Err_Ok;


    switch ( range->image_format )
    {
    case 1:
    case 2:
    case 8:
      /* variable small metrics */
      {
        TT_SBit_SmallMetricsRec  smetrics;

        static const FT_Frame_Field  sbit_small_metrics_fields[] =
        {
#undef  FT_STRUCTURE
#define FT_STRUCTURE  TT_SBit_SmallMetricsRec

          FT_FRAME_START( 5 ),
            FT_FRAME_BYTE( height ),
            FT_FRAME_BYTE( width ),
            FT_FRAME_CHAR( bearingX ),
            FT_FRAME_CHAR( bearingY ),
            FT_FRAME_BYTE( advance ),
          FT_FRAME_END
        };


        /* read small metrics */
        if ( FT_STREAM_READ_FIELDS( sbit_small_metrics_fields, &smetrics ) )
          goto Exit;

        /* convert it to a big metrics */
        metrics->height       = smetrics.height;
        metrics->width        = smetrics.width;
        metrics->horiBearingX = smetrics.bearingX;
        metrics->horiBearingY = smetrics.bearingY;
        metrics->horiAdvance  = smetrics.advance;

        /* these metrics are made up at a higher level when */
        /* needed.                                          */
        metrics->vertBearingX = 0;
        metrics->vertBearingY = 0;
        metrics->vertAdvance  = 0;
      }
      break;

    case 6:
    case 7:
    case 9:
      /* variable big metrics */
      if ( FT_STREAM_READ_FIELDS( sbit_metrics_fields, metrics ) )
        goto Exit;
      break;

    case 5:
    default:  /* constant metrics */
      if ( range->index_format == 2 || range->index_format == 5 )
        *metrics = range->metrics;
      else
        return SFNT_Err_Invalid_File_Format;
   }

  Exit:
    return error;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    crop_bitmap                                                        */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Crops a bitmap to its tightest bounding box, and adjusts its       */
  /*    metrics.                                                           */
  /*                                                                       */
  /* <InOut>                                                               */
  /*    map     :: The bitmap.                                             */
  /*                                                                       */
  /*    metrics :: The corresponding metrics structure.                    */
  /*                                                                       */
  static void
  crop_bitmap( FT_Bitmap*       map,
               TT_SBit_Metrics  metrics )
  {
    /***********************************************************************/
    /*                                                                     */
    /* In this situation, some bounding boxes of embedded bitmaps are too  */
    /* large.  We need to crop it to a reasonable size.                    */
    /*                                                                     */
    /*      ---------                                                      */
    /*      |       |                -----                                 */
    /*      |  ***  |                |***|                                 */
    /*      |   *   |                | * |                                 */
    /*      |   *   |    ------>     | * |                                 */
    /*      |   *   |                | * |                                 */
    /*      |   *   |                | * |                                 */
    /*      |  ***  |                |***|                                 */
    /*      ---------                -----                                 */
    /*                                                                     */
    /***********************************************************************/

    FT_Int    rows, count;
    FT_Long   line_len;
    FT_Byte*  line;


    /***********************************************************************/
    /*                                                                     */
    /* first of all, check the top-most lines of the bitmap, and remove    */
    /* them if they're empty.                                              */
    /*                                                                     */
    {
      line     = (FT_Byte*)map->buffer;
      rows     = map->rows;
      line_len = map->pitch;


      for ( count = 0; count < rows; count++ )
      {
        FT_Byte*  cur   = line;
        FT_Byte*  limit = line + line_len;


        for ( ; cur < limit; cur++ )
          if ( cur[0] )
            goto Found_Top;

        /* the current line was empty - skip to next one */
        line  = limit;
      }

    Found_Top:
      /* check that we have at least one filled line */
      if ( count >= rows )
        goto Empty_Bitmap;

      /* now, crop the empty upper lines */
      if ( count > 0 )
      {
        line = (FT_Byte*)map->buffer;

        FT_MEM_MOVE( line, line + count * line_len,
                     ( rows - count ) * line_len );

        metrics->height       = (FT_Byte)( metrics->height - count );
        metrics->horiBearingY = (FT_Char)( metrics->horiBearingY - count );
        metrics->vertBearingY = (FT_Char)( metrics->vertBearingY - count );

        map->rows -= count;
        rows      -= count;
      }
    }

    /***********************************************************************/
    /*                                                                     */
    /* second, crop the lower lines                                        */
    /*                                                                     */
    {
      line = (FT_Byte*)map->buffer + ( rows - 1 ) * line_len;

      for ( count = 0; count < rows; count++ )
      {
        FT_Byte*  cur   = line;
        FT_Byte*  limit = line + line_len;


        for ( ; cur < limit; cur++ )
          if ( cur[0] )
            goto Found_Bottom;

        /* the current line was empty - skip to previous one */
        line -= line_len;
      }

    Found_Bottom:
      if ( count > 0 )
      {
        metrics->height  = (FT_Byte)( metrics->height - count );
        rows            -= count;
        map->rows       -= count;
      }
    }

    /***********************************************************************/
    /*                                                                     */
    /* third, get rid of the space on the left side of the glyph           */
    /*                                                                     */
    do
    {
      FT_Byte*  limit;


      line  = (FT_Byte*)map->buffer;
      limit = line + rows * line_len;

      for ( ; line < limit; line += line_len )
        if ( line[0] & 0x80 )
          goto Found_Left;

      /* shift the whole glyph one pixel to the left */
      line  = (FT_Byte*)map->buffer;
      limit = line + rows * line_len;

      for ( ; line < limit; line += line_len )
      {
        FT_Int    n, width = map->width;
        FT_Byte   old;
        FT_Byte*  cur = line;


        old = (FT_Byte)(cur[0] << 1);
        for ( n = 8; n < width; n += 8 )
        {
          FT_Byte  val;


          val    = cur[1];
          cur[0] = (FT_Byte)( old | ( val >> 7 ) );
          old    = (FT_Byte)( val << 1 );
          cur++;
        }
        cur[0] = old;
      }

      map->width--;
      metrics->horiBearingX++;
      metrics->vertBearingX++;
      metrics->width--;

    } while ( map->width > 0 );

  Found_Left:

    /***********************************************************************/
    /*                                                                     */
    /* finally, crop the bitmap width to get rid of the space on the right */
    /* side of the glyph.                                                  */
    /*                                                                     */
    do
    {
      FT_Int    right = map->width - 1;
      FT_Byte*  limit;
      FT_Byte   mask;