ttraster.c

神龙卡开发原代码

        ras.lastX = (ras.lastX + x_last)/2;
        ras.lastY = (ras.lastY + y_last)/2;

        x_last = ras.lastX;
        y_last = ras.lastY;
      }
    }

    /* now process each contour point individually */
    while ( index < last )
    {
      index++;
      x = SCALED( ras.coords[index].x );
      y = SCALED( ras.coords[index].y );

      if ( flipped ) SWAP_( x, y );

      if ( on_curve )
      {
        /* the previous point was on the curve */
        on_curve = ( ras.flags[index] & 1 );
        if ( on_curve )
        {
          /* two successive on points => emit segment */
          if ( Line_To( RAS_VARS  x, y ) ) return FAILURE;
        }
        else
        {
          /* else, keep current control point for next bezier */
          cx = x;
          cy = y;
        }
      }
      else
      {
        /* the previous point was off the curve */
        on_curve = ( ras.flags[index] & 1 );
        if ( on_curve )
        {
          /* reaching an `on' point */
          if ( Bezier_To( RAS_VARS  x, y, cx, cy ) ) return FAILURE;
        }
        else
        {
          /* two successive `off' points => create middle point */
          mx = ( cx + x ) / 2;
          my = ( cy + y ) / 2;

          if ( Bezier_To( RAS_VARS  mx, my, cx, cy ) ) return FAILURE;

          cx = x;
          cy = y;
        }
      }
    }

    /* end of contour, close curve cleanly */
    if ( ras.flags[first] & 1 )
    {
      if ( on_curve )
        return Line_To( RAS_VARS  x_first, y_first );
      else
        return Bezier_To( RAS_VARS  x_first, y_first, cx, cy );
    }
    else
      if ( !on_curve )
        return Bezier_To( RAS_VARS  x_last, y_last, cx, cy );

    return SUCCESS;
  }


/****************************************************************************/
/*                                                                          */
/* Function:    Convert_Glyph                                               */
/*                                                                          */
/* Description: Converts a glyph into a series of segments and arcs         */
/*              and makes a Profiles list with them.                        */
/*                                                                          */
/* Input:       _xCoord, _yCoord : coordinates tables.                      */
/*                                                                          */
/*              Uses the 'Flag' table too.                                  */
/*                                                                          */
/* Returns:     SUCCESS on success.                                         */
/*              FAILURE if any error was encountered during rendering.      */
/*                                                                          */
/****************************************************************************/

  static Bool  Convert_Glyph( RAS_ARGS int  flipped )
  {
    Short     i;
    UShort    start;

    PProfile  lastProfile;


    ras.fProfile = NULL;
    ras.joint    = FALSE;
    ras.fresh    = FALSE;

    ras.maxBuff  = ras.sizeBuff - AlignProfileSize;

    ras.numTurns = 0;

    ras.cProfile         = (PProfile)ras.top;
    ras.cProfile->offset = ras.top;
    ras.num_Profs        = 0;

    start = 0;

    for ( i = 0; i < ras.nContours; i++ )
    {
      ras.state    = Unknown;
      ras.gProfile = NULL;

      if ( Decompose_Curve( RAS_VARS  start, ras.outs[i], flipped ) )
        return FAILURE;

      start = ras.outs[i] + 1;

      /* We must now see if the extreme arcs join or not */
      if ( ( FRAC( ras.lastY ) == 0 &&
             ras.lastY >= ras.minY      &&
             ras.lastY <= ras.maxY ) )
        if ( ras.gProfile && ras.gProfile->flow == ras.cProfile->flow )
          ras.top--;
        /* Note that ras.gProfile can be nil if the contour was too small */
        /* to be drawn.                                                   */

      lastProfile = ras.cProfile;
      if ( End_Profile( RAS_VAR ) ) return FAILURE;

      /* close the 'next profile in contour' linked list */
      if ( ras.gProfile )
        lastProfile->next = ras.gProfile;
    }

    if (Finalize_Profile_Table( RAS_VAR ))
      return FAILURE;

    return (ras.top < ras.maxBuff ? SUCCESS : FAILURE );
  }


/************************************************/
/*                                              */
/*  Init_Linked                                 */
/*                                              */
/*    Inits an empty linked list.               */
/*                                              */
/************************************************/

  static void  Init_Linked( TProfileList*  l )
  {
    *l = NULL;
  }


/************************************************/
/*                                              */
/*  InsNew :                                    */
/*                                              */
/*    Inserts a new Profile in a linked list.   */
/*                                              */
/************************************************/

  static void  InsNew( PProfileList  list,
                       PProfile      profile )
  {
    PProfile  *old, current;
    Long       x;


    old     = list;
    current = *old;
    x       = profile->X;

    while ( current )
    {
      if ( x < current->X )
        break;
      old     = &current->link;
      current = *old;
    }

    profile->link = current;
    *old          = profile;
  }


/*************************************************/
/*                                               */
/*  DelOld :                                     */
/*                                               */
/*    Removes an old Profile from a linked list. */
/*                                               */
/*************************************************/

  static void  DelOld( PProfileList  list,
                       PProfile      profile )
  {
    PProfile  *old, current;


    old     = list;
    current = *old;

    while ( current )
    {
      if ( current == profile )
      {
        *old = current->link;
        return;
      }

      old     = &current->link;
      current = *old;
    }

    /* we should never get there, unless the Profile was not part of */
    /* the list.                                                     */
  }


/************************************************/
/*                                              */
/*  Update :                                    */
/*                                              */
/*    Update all X offsets of a drawing list    */
/*                                              */
/************************************************/

  static void  Update( PProfile  first )
  {
    PProfile  current = first;


    while ( current )
    {
      current->X       = *current->offset;
      current->offset += current->flow;
      current->height--;
      current = current->link;
    }
  }


/************************************************/
/*                                              */
/*  Sort :                                      */
/*                                              */
/*    Sorts a trace list.  In 95%, the list     */
/*    is already sorted.  We need an algorithm  */
/*    which is fast in this case.  Bubble sort  */
/*    is enough and simple.                     */
/*                                              */
/************************************************/

  static void  Sort( PProfileList  list )
  {
    PProfile  *old, current, next;


    /* First, set the new X coordinate of each profile */
    Update( *list );

    /* Then sort them */
    old     = list;
    current = *old;

    if ( !current )
      return;

    next = current->link;

    while ( next )
    {
      if ( current->X <= next->X )
      {
        old     = &current->link;
        current = *old;

        if ( !current )
          return;
      }
      else
      {
        *old          = next;
        current->link = next->link;
        next->link    = current;

        old     = list;
        current = *old;
      }

      next = current->link;
    }
  }


/***********************************************************************/
/*                                                                     */
/*  Vertical Sweep Procedure Set :                                     */
/*                                                                     */
/*  These three routines are used during the vertical black/white      */
/*  sweep phase by the generic Draw_Sweep() function.                  */
/*                                                                     */
/***********************************************************************/

  static void  Vertical_Sweep_Init( RAS_ARGS Short*  min, Short*  max )
  {
    switch ( ras.target.flow )
    {
    case TT_Flow_Up:
      ras.traceOfs  = *min * ras.target.cols;
      ras.traceIncr = ras.target.cols;
      break;

    default:
      ras.traceOfs  = ( ras.target.rows - 1 - *min ) * ras.target.cols;
      ras.traceIncr = -ras.target.cols;
    }

    ras.gray_min_x = 0;
    ras.gray_max_x = 0;
  }


  static void  Vertical_Sweep_Span( RAS_ARGS Short       y,
                                             TT_F26Dot6  x1,
                                             TT_F26Dot6  x2,
                                             PProfile    left,
                                             PProfile    right )
  {
    Long   e1, e2;
    Short  c1, c2;
    Short  f1, f2;
    Byte*  target;


    /* Drop-out control */

    e1 = TRUNC( CEILING( x1 ) );

    if ( x2-x1-ras.precision <= ras.precision_jitter )
      e2 = e1;
    else
      e2 = TRUNC( FLOOR( x2 ) );

    if ( e2 >= 0 && e1 < ras.bWidth )
    {
      if ( e1 < 0 )           e1 = 0;
      if ( e2 >= ras.bWidth ) e2 = ras.bWidth-1;

      c1 = (Short)(e1 >> 3);
      c2 = (Short)(e2 >> 3);

      f1 = e1 & 7;
      f2 = e2 & 7;

      if ( ras.gray_min_x > c1 ) ras.gray_min_x = c1;
      if ( ras.gray_max_x < c2 ) ras.gray_max_x = c2;

      target = ras.bTarget + ras.traceOfs + c1;

      if ( c1 != c2 )
      {
        *target |= LMask[f1];

        if ( c2 > c1 + 1 )
          MEM_Set( target + 1, 0xFF, c2 - c1 - 1 );

        target[c2 - c1] |= RMask[f2];
      }
      else
        *target |= ( LMask[f1] & RMask[f2] );
    }
  }


  static void  Vertical_Sweep_Drop( RAS_ARGS Short       y,
                                             TT_F26Dot6  x1,
                                             TT_F26Dot6  x2,
                                             PProfile    left,
                                             PProfile    right )
  {
    Long   e1, e2;
    Short  c1, f1;


    /* Drop-out control */

    e1 = CEILING( x1 );
    e2 = FLOOR  ( x2 );

    if ( e1 > e2 )
    {
      if ( e1 == e2 + ras.precision )
      {
        switch ( ras.dropOutControl )
        {
        case 1:
          e1 = e2;
          break;

        case 4:
          e1 = CEILING( (x1 + x2 + 1) / 2 );
          break;

        case 2:
        case 5:
          /* Drop-out Control Rule #4 */

          /* The spec is not very clear regarding rule #4.  It      */
          /* presents a method that is way too costly to implement  */
          /* while the general idea seems to get rid of 'stubs'.    */
          /*                                                        */
          /* Here, we only get rid of stubs recognized when:        */
          /*                                                        */
          /*  upper stub:                                           */
          /*                                                        */
          /*   - P_Left and P_Right are in the same contour         */
          /*   - P_Right is the successor of P_Left in that contour */
          /*   - y is the top of P_Left and P_Right                 */
          /*                                                        */
          /*  lower stub:                                           */
          /*                                                        */
          /*   - P_Left and P_Right are in the same contour         */