pshalgo2.c

a very goog book

#ifdef DEBUG_ZONES

#include <stdio.h>

  static void
  psh2_print_zone( PSH2_Zone  zone )
  {
    printf( "zone [scale,delta,min,max] = [%.3f,%.3f,%d,%d]\n",
             zone->scale/65536.0,
             zone->delta/64.0,
             zone->min,
             zone->max );
  }

#else

#define psh2_print_zone( x )   do { } while ( 0 )

#endif

#if 0
  /* setup interpolation zones once the hints have been grid-fitted */
  /* by the optimizer                                               */
  static void
  psh2_hint_table_setup_zones( PSH2_Hint_Table  table,
                               FT_Fixed         scale,
                               FT_Fixed         delta )
  {
    FT_UInt     count;
    PSH2_Zone   zone;
    PSH2_Hint  *sort, hint, hint2;


    zone = table->zones;

    /* special case, no hints defined */
    if ( table->num_hints == 0 )
    {
      zone->scale = scale;
      zone->delta = delta;
      zone->min   = PSH2_ZONE_MIN;
      zone->max   = PSH2_ZONE_MAX;

      table->num_zones = 1;
      table->zone      = zone;
      return;
    }

    /* the first zone is before the first hint */
    /* x' = (x-x0)*s + x0' = x*s + ( x0' - x0*s ) */
    sort = table->sort;
    hint = sort[0];

    zone->scale = scale;
    zone->delta = hint->cur_pos - FT_MulFix( hint->org_pos, scale );
    zone->min   = PSH2_ZONE_MIN;
    zone->max   = hint->org_pos;

    psh2_print_zone( zone );

    zone++;

    for ( count = table->num_hints; count > 0; count-- )
    {
      FT_Fixed  scale2;


      if ( hint->org_len > 0 )
      {
        /* setup a zone for inner-stem interpolation */
        /* (x' - x0') = (x - x0)*(x1'-x0')/(x1-x0)   */
        /* x' = x*s2 + x0' - x0*s2                   */

        scale2      = FT_DivFix( hint->cur_len, hint->org_len );
        zone->scale = scale2;
        zone->min   = hint->org_pos;
        zone->max   = hint->org_pos + hint->org_len;
        zone->delta = hint->cur_pos - FT_MulFix( zone->min, scale2 );

        psh2_print_zone( zone );

        zone++;
      }

      if ( count == 1 )
        break;

      sort++;
      hint2 = sort[0];

      /* setup zone for inter-stem interpolation */
      /* (x'-x1') = (x-x1)*(x2'-x1')/(x2-x1)     */
      /* x' = x*s3 + x1' - x1*s3                 */

      scale2 = FT_DivFix( hint2->cur_pos - (hint->cur_pos + hint->cur_len),
                          hint2->org_pos - (hint->org_pos + hint->org_len) );
      zone->scale = scale2;
      zone->min   = hint->org_pos + hint->org_len;
      zone->max   = hint2->org_pos;
      zone->delta = hint->cur_pos + hint->cur_len -
                    FT_MulFix( zone->min, scale2 );

      psh2_print_zone( zone );

      zone++;

      hint = hint2;
    }

    /* the last zone */
    zone->scale = scale;
    zone->min   = hint->org_pos + hint->org_len;
    zone->max   = PSH2_ZONE_MAX;
    zone->delta = hint->cur_pos + hint->cur_len -
                  FT_MulFix( zone->min, scale );

    psh2_print_zone( zone );

    zone++;

    table->num_zones = zone - table->zones;
    table->zone      = table->zones;
  }
#endif

#if 0
  /* tune a single coordinate with the current interpolation zones */
  static FT_Pos
  psh2_hint_table_tune_coord( PSH2_Hint_Table  table,
                              FT_Int           coord )
  {
    PSH2_Zone   zone;


    zone = table->zone;

    if ( coord < zone->min )
    {
      do
      {
        if ( zone == table->zones )
          break;

        zone--;

      } while ( coord < zone->min );
      table->zone = zone;
    }
    else if ( coord > zone->max )
    {
      do
      {
        if ( zone == table->zones + table->num_zones - 1 )
          break;

        zone++;

      } while ( coord > zone->max );
      table->zone = zone;
    }

    return FT_MulFix( coord, zone->scale ) + zone->delta;
  }
#endif

#if 0
 /* tune a given outline with current interpolation zones */
 /* the function only works in a single dimension..       */
  static void
  psh2_hint_table_tune_outline( PSH2_Hint_Table  table,
                                FT_Outline*      outline,
                                PSH_Globals      globals,
                                FT_Int           dimension )

  {
    FT_UInt        count, first, last;
    PS_Mask_Table  hint_masks = table->hint_masks;
    PS_Mask        mask;
    PSH_Dimension  dim        = &globals->dimension[dimension];
    FT_Fixed       scale      = dim->scale_mult;
    FT_Fixed       delta      = dim->scale_delta;


    if ( hint_masks && hint_masks->num_masks > 0 )
    {
      first = 0;
      mask  = hint_masks->masks;
      count = hint_masks->num_masks;

      for ( ; count > 0; count--, mask++ )
      {
        last = mask->end_point;

        if ( last > first )
        {
          FT_Vector*   vec;
          FT_Int       count2;


          psh2_hint_table_activate_mask( table, mask );
          psh2_hint_table_optimize( table, globals, outline, dimension );
          psh2_hint_table_setup_zones( table, scale, delta );
          last = mask->end_point;

          vec    = outline->points + first;
          count2 = last - first;

          for ( ; count2 > 0; count2--, vec++ )
          {
            FT_Pos  x, *px;


            px  = dimension ? &vec->y : &vec->x;
            x   = *px;

            *px = psh2_hint_table_tune_coord( table, (FT_Int)x );
          }
        }

        first = last;
      }
    }
    else    /* no hints in this glyph, simply scale the outline */
    {
      FT_Vector*  vec;


      vec   = outline->points;
      count = outline->n_points;

      if ( dimension == 0 )
      {
        for ( ; count > 0; count--, vec++ )
          vec->x = FT_MulFix( vec->x, scale ) + delta;
      }
      else
      {
        for ( ; count > 0; count--, vec++ )
          vec->y = FT_MulFix( vec->y, scale ) + delta;
      }
    }
  }
#endif


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                    HINTER GLYPH MANAGEMENT                    *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  static int
  psh2_point_is_extremum( PSH2_Point  point )
  {
    PSH2_Point  before = point;
    PSH2_Point  after  = point;
    FT_Pos      d_before;
    FT_Pos      d_after;


    do
    {
      before = before->prev;
      if ( before == point )
        return 0;

      d_before = before->org_u - point->org_u;

    } while ( d_before == 0 );

    do
    {
      after = after->next;
      if ( after == point )
        return 0;

      d_after = after->org_u - point->org_u;

    } while ( d_after == 0 );

    return ( ( d_before > 0 && d_after > 0 ) ||
             ( d_before < 0 && d_after < 0 ) );
  }


  static void
  psh2_glyph_done( PSH2_Glyph  glyph )
  {
    FT_Memory  memory = glyph->memory;


    psh2_hint_table_done( &glyph->hint_tables[1], memory );
    psh2_hint_table_done( &glyph->hint_tables[0], memory );

    FT_FREE( glyph->points );
    FT_FREE( glyph->contours );

    glyph->num_points   = 0;
    glyph->num_contours = 0;

    glyph->memory = 0;
  }


  static int
  psh2_compute_dir( FT_Pos  dx,
                    FT_Pos  dy )
  {
    FT_Pos  ax, ay;
    int     result = PSH2_DIR_NONE;


    ax = ( dx >= 0 ) ? dx : -dx;
    ay = ( dy >= 0 ) ? dy : -dy;

    if ( ay * 12 < ax )
    {
      /* |dy| <<< |dx|  means a near-horizontal segment */
      result = ( dx >= 0 ) ? PSH2_DIR_RIGHT : PSH2_DIR_LEFT;
    }
    else if ( ax * 12 < ay )
    {
      /* |dx| <<< |dy|  means a near-vertical segment */
      result = ( dy >= 0 ) ? PSH2_DIR_UP : PSH2_DIR_DOWN;
    }

    return result;
  }


  static FT_Error
  psh2_glyph_init( PSH2_Glyph   glyph,
                   FT_Outline*  outline,
                   PS_Hints     ps_hints,
                   PSH_Globals  globals )
  {
    FT_Error   error;
    FT_Memory  memory;


    /* clear all fields */
    ft_memset( glyph, 0, sizeof ( *glyph ) );

    memory = globals->memory;

    /* allocate and setup points + contours arrays */
    if ( FT_NEW_ARRAY( glyph->points,   outline->n_points   ) ||
         FT_NEW_ARRAY( glyph->contours, outline->n_contours ) )
      goto Exit;

    glyph->num_points   = outline->n_points;
    glyph->num_contours = outline->n_contours;

    {
      FT_UInt       first = 0, next, n;
      PSH2_Point    points  = glyph->points;
      PSH2_Contour  contour = glyph->contours;


      for ( n = 0; n < glyph->num_contours; n++ )
      {
        FT_Int      count;
        PSH2_Point  point;


        next  = outline->contours[n] + 1;
        count = next - first;

        contour->start = points + first;
        contour->count = (FT_UInt)count;

        if ( count > 0 )
        {
          point = points + first;

          point->prev    = points + next - 1;
          point->contour = contour;

          for ( ; count > 1; count-- )
          {
            point[0].next = point + 1;
            point[1].prev = point;
            point++;
            point->contour = contour;
          }
          point->next = points + first;
        }

        contour++;
        first = next;
      }
    }

    {
      PSH2_Point  points = glyph->points;
      PSH2_Point  point  = points;
      FT_Vector*  vec    = outline->points;
      FT_UInt     n;


      for ( n = 0; n < glyph->num_points; n++, point++ )
      {
        FT_Int  n_prev = point->prev - points;
        FT_Int  n_next = point->next - points;
        FT_Pos  dxi, dyi, dxo, dyo;


        if ( !( outline->tags[n] & FT_Curve_Tag_On ) )
          point->flags = PSH2_POINT_OFF;

        dxi = vec[n].x - vec[n_prev].x;
        dyi = vec[n].y - vec[n_prev].y;

        point->dir_in = (FT_Char)psh2_compute_dir( dxi, dyi );

        dxo = vec[n_next].x - vec[n].x;
        dyo = vec[n_next].y - vec[n].y;

        point->dir_out = (FT_Char)psh2_compute_dir( dxo, dyo );

        /* detect smooth points */
        if ( point->flags & PSH2_POINT_OFF )
          point->flags |= PSH2_POINT_SMOOTH;
        else if ( point->dir_in  != PSH2_DIR_NONE ||
                  point->dir_out != PSH2_DIR_NONE )
        {
          if ( point->dir_in == point->dir_out )
            point->flags |= PSH2_POINT_SMOOTH;
        }
        else
        {
          FT_Angle  angle_in, angle_out, diff;


          angle_in  = FT_Atan2( dxi, dyi );
          angle_out = FT_Atan2( dxo, dyo );

          diff = angle_in - angle_out;
          if ( diff < 0 )
            diff = -diff;

          if ( diff > FT_ANGLE_PI )
            diff = FT_ANGLE_2PI - diff;

          if ( diff < FT_ANGLE_PI / 16 )
            point->flags |= PSH2_POINT_SMOOTH;
        }
      }
    }

    glyph->memory  = memory;
    glyph->outline = outline;
    glyph->globals = globals;

    /* now deal with hints tables */
    error = psh2_hint_table_init( &glyph->hint_tables [0],
                                  &ps_hints->dimension[0].hints,
                                  &ps_hints->dimension[0].masks,
                                  &ps_hints->dimension[0].counters,
                                  memory );
    if ( error )
      goto Exit;

    error = psh2_hint_table_init( &glyph->hint_tables [1],
                                  &ps_hints->dimension[1].hints,
                                  &ps_hints->dimension[1].masks,
                                  &ps_hints->dimension[1].counters,
                                  memory );
    if ( error )
      goto Exit;

  Exit:
    return error;
  }


  /* load outline point coordinates into hinter glyph */
  static void
  psh2_glyph_load_points( PSH2_Glyph  glyph,
                          FT_Int      dimension )
  {
    FT_Vector*  vec   = glyph->outline->points;
    PSH2_Point  point = glyph->points;
    FT_UInt     count = glyph->num_points;


    for ( ; count > 0; count--, point++, vec++ )
    {
      point->flags &= PSH2_POINT_OFF | PSH2_POINT_SMOOTH;
      point->hint   = 0;
      if ( dimension == 0 )
        point->org_u = vec->x;
      else
        point->org_u = vec->y;

#ifdef DEBUG_HINTER
      point->org_x = vec->x;
      point->org_y = vec->y;
#endif
    }
  }


  /* save hinted point coordinates back to outline */
  static void
  psh2_glyph_save_points( PSH2_Glyph  glyph,
                          FT_Int      dimension )
  {
    FT_UInt     n;
    PSH2_Point  point = glyph->points;
    FT_Vector*  vec   = glyph->outline->points;
    char*       tags  = glyph->outline->tags;


    for ( n = 0; n < glyph->num_points; n++ )
    {