ttinterp.c

source code: Covert TXT to PDF

    return (FT_Short)( ( CUR.code[CUR.IP - 2] << 8 ) +
                         CUR.code[CUR.IP - 1]      );
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Ins_Goto_CodeRange                                                 */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Goes to a certain code range in the instruction stream.            */
  /*                                                                       */
  /* <Input>                                                               */
  /*    aRange :: The index of the code range.                             */
  /*                                                                       */
  /*    aIP    :: The new IP address in the code range.                    */
  /*                                                                       */
  /* <Return>                                                              */
  /*    SUCCESS or FAILURE.                                                */
  /*                                                                       */
  static FT_Bool
  Ins_Goto_CodeRange( EXEC_OP_ FT_Int    aRange,
                               FT_ULong  aIP )
  {
    TT_CodeRange*  range;


    if ( aRange < 1 || aRange > 3 )
    {
      CUR.error = TT_Err_Bad_Argument;
      return FAILURE;
    }

    range = &CUR.codeRangeTable[aRange - 1];

    if ( range->base == NULL )     /* invalid coderange */
    {
      CUR.error = TT_Err_Invalid_CodeRange;
      return FAILURE;
    }

    /* NOTE: Because the last instruction of a program may be a CALL */
    /*       which will return to the first byte *after* the code    */
    /*       range, we test for AIP <= Size, instead of AIP < Size.  */

    if ( aIP > range->size )
    {
      CUR.error = TT_Err_Code_Overflow;
      return FAILURE;
    }

    CUR.code     = range->base;
    CUR.codeSize = range->size;
    CUR.IP       = aIP;
    CUR.curRange = aRange;

    return SUCCESS;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Direct_Move                                                        */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Moves a point by a given distance along the freedom vector.  The   */
  /*    point will be `touched'.                                           */
  /*                                                                       */
  /* <Input>                                                               */
  /*    point    :: The index of the point to move.                        */
  /*                                                                       */
  /*    distance :: The distance to apply.                                 */
  /*                                                                       */
  /* <InOut>                                                               */
  /*    zone     :: The affected glyph zone.                               */
  /*                                                                       */
  static void
  Direct_Move( EXEC_OP_ TT_GlyphZone*  zone,
                        FT_UShort      point,
                        FT_F26Dot6     distance )
  {
    FT_F26Dot6 v;


    v = CUR.GS.freeVector.x;

    if ( v != 0 )
    {

#ifdef NO_APPLE_PATENT

      if ( ABS( CUR.F_dot_P ) > APPLE_THRESHOLD )
        zone->cur[point].x += distance;

#else

      zone->cur[point].x += TT_MULDIV( distance,
                                       v * 0x10000L,
                                       CUR.F_dot_P );

#endif

      zone->tags[point] |= FT_Curve_Tag_Touch_X;
    }

    v = CUR.GS.freeVector.y;

    if ( v != 0 )
    {

#ifdef NO_APPLE_PATENT

      if ( ABS( CUR.F_dot_P ) > APPLE_THRESHOLD )
        zone->cur[point].y += distance;

#else

      zone->cur[point].y += TT_MULDIV( distance,
                                       v * 0x10000L,
                                       CUR.F_dot_P );

#endif

      zone->tags[point] |= FT_Curve_Tag_Touch_Y;
    }
  }


  /*************************************************************************/
  /*                                                                       */
  /* Special versions of Direct_Move()                                     */
  /*                                                                       */
  /*   The following versions are used whenever both vectors are both      */
  /*   along one of the coordinate unit vectors, i.e. in 90% of the cases. */
  /*                                                                       */
  /*************************************************************************/


  static void
  Direct_Move_X( EXEC_OP_ TT_GlyphZone*  zone,
                          FT_UShort      point,
                          FT_F26Dot6     distance )
  {
    FT_UNUSED_EXEC;

    zone->cur[point].x += distance;
    zone->tags[point]  |= FT_Curve_Tag_Touch_X;
  }


  static void
  Direct_Move_Y( EXEC_OP_ TT_GlyphZone*  zone,
                          FT_UShort      point,
                          FT_F26Dot6     distance )
  {
    FT_UNUSED_EXEC;

    zone->cur[point].y += distance;
    zone->tags[point]  |= FT_Curve_Tag_Touch_Y;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Round_None                                                         */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Does not round, but adds engine compensation.                      */
  /*                                                                       */
  /* <Input>                                                               */
  /*    distance     :: The distance (not) to round.                       */
  /*                                                                       */
  /*    compensation :: The engine compensation.                           */
  /*                                                                       */
  /* <Return>                                                              */
  /*    The compensated distance.                                          */
  /*                                                                       */
  /* <Note>                                                                */
  /*    The TrueType specification says very few about the relationship    */
  /*    between rounding and engine compensation.  However, it seems from  */
  /*    the description of super round that we should add the compensation */
  /*    before rounding.                                                   */
  /*                                                                       */
  static FT_F26Dot6
  Round_None( EXEC_OP_ FT_F26Dot6  distance,
                       FT_F26Dot6  compensation )
  {
    FT_F26Dot6  val;

    FT_UNUSED_EXEC;


    if ( distance >= 0 )
    {
      val = distance + compensation;
      if ( val < 0 )
        val = 0;
    }
    else {
      val = distance - compensation;
      if ( val > 0 )
        val = 0;
    }
    return val;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Round_To_Grid                                                      */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Rounds value to grid after adding engine compensation.             */
  /*                                                                       */
  /* <Input>                                                               */
  /*    distance     :: The distance to round.                             */
  /*                                                                       */
  /*    compensation :: The engine compensation.                           */
  /*                                                                       */
  /* <Return>                                                              */
  /*    Rounded distance.                                                  */
  /*                                                                       */
  static FT_F26Dot6
  Round_To_Grid( EXEC_OP_ FT_F26Dot6  distance,
                          FT_F26Dot6  compensation )
  {
    FT_F26Dot6  val;

    FT_UNUSED_EXEC;


    if ( distance >= 0 )
    {
      val = distance + compensation + 32;
      if ( val > 0 )
        val &= ~63;
      else
        val = 0;
    }
    else
    {
      val = -( ( compensation - distance + 32 ) & -64 );
      if ( val > 0 )
        val = 0;
    }

    return  val;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Round_To_Half_Grid                                                 */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Rounds value to half grid after adding engine compensation.        */
  /*                                                                       */
  /* <Input>                                                               */
  /*    distance     :: The distance to round.                             */
  /*                                                                       */
  /*    compensation :: The engine compensation.                           */
  /*                                                                       */
  /* <Return>                                                              */
  /*    Rounded distance.                                                  */
  /*                                                                       */
  static FT_F26Dot6
  Round_To_Half_Grid( EXEC_OP_ FT_F26Dot6  distance,
                               FT_F26Dot6  compensation )
  {
    FT_F26Dot6  val;

    FT_UNUSED_EXEC;


    if ( distance >= 0 )
    {
      val = ( ( distance + compensation ) & -64 ) + 32;
      if ( val < 0 )
        val = 0;
    }
    else
    {
      val = -( ( (compensation - distance) & -64 ) + 32 );
      if ( val > 0 )
        val = 0;
    }

    return val;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Round_Down_To_Grid                                                 */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Rounds value down to grid after adding engine compensation.        */
  /*                                                                       */
  /* <Input>                                                               */
  /*    distance     :: The distance to round.                             */
  /*                                                                       */
  /*    compensation :: The engine compensation.                           */
  /*                                                                       */
  /* <Return>                                                              */
  /*    Rounded distance.                                                  */
  /*                                                                       */
  static FT_F26Dot6
  Round_Down_To_Grid( EXEC_OP_ FT_F26Dot6  distance,
                               FT_F26Dot6  compensation )
  {
    FT_F26Dot6  val;

    FT_UNUSED_EXEC;


    if ( distance >= 0 )
    {
      val = distance + compensation;
      if ( val > 0 )
        val &= ~63;
      else