pfrsbit.h File Reference

#include "pfrobjs.h"

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Functions
FT_BEGIN_HEADER	pfr_slot_load_bitmap (PFR_Slot glyph, PFR_Size size, FT_UInt glyph_index, FT_Bool metrics_only)

Function Documentation

pfr_slot_load_bitmap()

FT_BEGIN_HEADER pfr_slot_load_bitmap	(	PFR_Slot	glyph,
		PFR_Size	size,
		FT_UInt	glyph_index,
		FT_Bool	metrics_only
	)

Definition at line 579 of file pfrsbit.c.

  {
    FT_Error     error;
    PFR_Face     face   = (PFR_Face) glyph->root.face;
    FT_Stream    stream = face->root.stream;
    PFR_PhyFont  phys   = &face->phy_font;
    FT_ULong     gps_offset;
    FT_ULong     gps_size;
    PFR_Char     character;
    PFR_Strike   strike;


    character = &phys->chars[glyph_index];

    /* look up a bitmap strike corresponding to the current */
    /* character dimensions                                 */
    {
      FT_UInt  n;


      strike = phys->strikes;
      for ( n = 0; n < phys->num_strikes; n++ )
      {
        if ( strike->x_ppm == (FT_UInt)size->root.metrics.x_ppem &&
             strike->y_ppm == (FT_UInt)size->root.metrics.y_ppem )
          goto Found_Strike;

        strike++;
      }

      /* couldn't find it */
      return FT_THROW( Invalid_Argument );
    }

  Found_Strike:

    /* now look up the glyph's position within the file */
    {
      FT_UInt  char_len;


      char_len = 4;
      if ( strike->flags & PFR_BITMAP_2BYTE_CHARCODE )
        char_len += 1;
      if ( strike->flags & PFR_BITMAP_2BYTE_SIZE )
        char_len += 1;
      if ( strike->flags & PFR_BITMAP_3BYTE_OFFSET )
        char_len += 1;

      /* access data directly in the frame to speed lookups */
      if ( FT_STREAM_SEEK( phys->bct_offset + strike->bct_offset ) ||
           FT_FRAME_ENTER( char_len * strike->num_bitmaps )        )
        goto Exit;

      pfr_lookup_bitmap_data( stream->cursor,
                              stream->limit,
                              strike->num_bitmaps,
                              &strike->flags,
                              character->char_code,
                              &gps_offset,
                              &gps_size );

      FT_FRAME_EXIT();

      if ( gps_size == 0 )
      {
        /* could not find a bitmap program string for this glyph */
        error = FT_THROW( Invalid_Argument );
        goto Exit;
      }
    }

    /* get the bitmap metrics */
    {
      FT_Long   xpos = 0, ypos = 0, advance = 0;
      FT_UInt   xsize = 0, ysize = 0, format = 0;
      FT_Byte*  p;


      /* compute linear advance */
      advance = character->advance;
      if ( phys->metrics_resolution != phys->outline_resolution )
        advance = FT_MulDiv( advance,
                             (FT_Long)phys->outline_resolution,
                             (FT_Long)phys->metrics_resolution );

      glyph->root.linearHoriAdvance = advance;

      /* compute default advance, i.e., scaled advance; this can be */
      /* overridden in the bitmap header of certain glyphs          */
      advance = FT_MulDiv( (FT_Fixed)size->root.metrics.x_ppem << 8,
                           character->advance,
                           (FT_Long)phys->metrics_resolution );

      if ( FT_STREAM_SEEK( face->header.gps_section_offset + gps_offset ) ||
           FT_FRAME_ENTER( gps_size )                                     )
        goto Exit;

      p     = stream->cursor;
      error = pfr_load_bitmap_metrics( &p, stream->limit,
                                       advance,
                                       &xpos, &ypos,
                                       &xsize, &ysize,
                                       &advance, &format );
      if ( error )
        goto Exit1;

      /*
       * Before allocating the target bitmap, we check whether the given
       * bitmap dimensions are valid, depending on the image format.
       *
       * Format 0: We have a stream of pixels (with 8 pixels per byte).
       *
       *             (xsize * ysize + 7) / 8 <= gps_size
       *
       * Format 1: Run-length encoding; the high nibble holds the number of
       *           white bits, the low nibble the number of black bits.  In
       *           other words, a single byte can represent at most 15
       *           pixels.
       *
       *             xsize * ysize <= 15 * gps_size
       *
       * Format 2: Run-length encoding; the high byte holds the number of
       *           white bits, the low byte the number of black bits.  In
       *           other words, two bytes can represent at most 255 pixels.
       *
       *             xsize * ysize <= 255 * (gps_size + 1) / 2
       */
      switch ( format )
      {
      case 0:
        if ( ( (FT_ULong)xsize * ysize + 7 ) / 8 > gps_size )
          error = FT_THROW( Invalid_Table );
        break;
      case 1:
        if ( (FT_ULong)xsize * ysize > 15 * gps_size )
          error = FT_THROW( Invalid_Table );
        break;
      case 2:
        if ( (FT_ULong)xsize * ysize > 255 * ( ( gps_size + 1 ) / 2 ) )
          error = FT_THROW( Invalid_Table );
        break;
      default:
        FT_ERROR(( "pfr_slot_load_bitmap: invalid image type\n" ));
        error = FT_THROW( Invalid_Table );
      }

      if ( error )
      {
        if ( FT_ERR_EQ( error, Invalid_Table ) )
          FT_ERROR(( "pfr_slot_load_bitmap: invalid bitmap dimensions\n" ));
        goto Exit1;
      }

      /*
       * XXX: on 16bit systems we return an error for huge bitmaps
       *      that cause size truncation, because truncated
       *      size properties make bitmap glyphs broken.
       */
      if ( xpos > FT_INT_MAX                  ||
           xpos < FT_INT_MIN                  ||
           ysize > FT_INT_MAX                 ||
           ypos > FT_INT_MAX - (FT_Long)ysize ||
           ypos + (FT_Long)ysize < FT_INT_MIN )
      {
        FT_TRACE1(( "pfr_slot_load_bitmap:" ));
        FT_TRACE1(( "huge bitmap glyph %dx%d over FT_GlyphSlot\n",
                     xpos, ypos ));
        error = FT_THROW( Invalid_Pixel_Size );
      }

      if ( !error )
      {
        glyph->root.format = FT_GLYPH_FORMAT_BITMAP;

        /* Set up glyph bitmap and metrics */

        /* XXX: needs casts to fit FT_Bitmap.{width|rows|pitch} */
        glyph->root.bitmap.width      = xsize;
        glyph->root.bitmap.rows       = ysize;
        glyph->root.bitmap.pitch      = (FT_Int)( xsize + 7 ) >> 3;
        glyph->root.bitmap.pixel_mode = FT_PIXEL_MODE_MONO;

        /* XXX: needs casts to fit FT_Glyph_Metrics.{width|height} */
        glyph->root.metrics.width        = (FT_Pos)xsize << 6;
        glyph->root.metrics.height       = (FT_Pos)ysize << 6;
        glyph->root.metrics.horiBearingX = xpos * 64;
        glyph->root.metrics.horiBearingY = ypos * 64;
        glyph->root.metrics.horiAdvance  = FT_PIX_ROUND( ( advance >> 2 ) );
        glyph->root.metrics.vertBearingX = - glyph->root.metrics.width >> 1;
        glyph->root.metrics.vertBearingY = 0;
        glyph->root.metrics.vertAdvance  = size->root.metrics.height;

        /* XXX: needs casts fit FT_GlyphSlotRec.bitmap_{left|top} */
        glyph->root.bitmap_left = (FT_Int)xpos;
        glyph->root.bitmap_top  = (FT_Int)( ypos + (FT_Long)ysize );

        if ( metrics_only )
          goto Exit1;

        /* Allocate and read bitmap data */
        {
          FT_ULong  len = (FT_ULong)glyph->root.bitmap.pitch * ysize;


          error = ft_glyphslot_alloc_bitmap( &glyph->root, len );
          if ( !error )
            error = pfr_load_bitmap_bits(
                      p,
                      stream->limit,
                      format,
                      FT_BOOL( face->header.color_flags &
                               PFR_FLAG_INVERT_BITMAP   ),
                      &glyph->root.bitmap );
        }
      }

    Exit1:
      FT_FRAME_EXIT();
    }

  Exit:
    return error;
  }

Referenced by pfr_slot_load().