pshalgo.c

下载来的一个看图软件的源代码

          if ( parent )
          {
            FT_Pos  par_org_center, par_cur_center;
            FT_Pos  cur_org_center, cur_delta;


            /* ensure that parent is already fitted */
            if ( !psh_hint_is_fitted( parent ) )
              psh_hint_align( parent, globals, dimension, glyph );

            par_org_center = parent->org_pos + ( parent->org_len >> 1 );
            par_cur_center = parent->cur_pos + ( parent->cur_len >> 1 );
            cur_org_center = hint->org_pos   + ( hint->org_len   >> 1 );

            cur_delta = FT_MulFix( cur_org_center - par_org_center, scale );
            pos       = par_cur_center + cur_delta - ( len >> 1 );
          }

          hint->cur_pos = pos;
          hint->cur_len = fit_len;

          /* Stem adjustment tries to snap stem widths to standard
           * ones.  This is important to prevent unpleasant rounding
           * artefacts.
           */
          if ( glyph->do_stem_adjust )
          {
            if ( len <= 64 )
            {
              /* the stem is less than one pixel; we will center it
               * around the nearest pixel center
               */
#if 1
              pos = ( pos + ( len >> 1 ) ) & -64;
#else
             /* this seems to be a bug! */
              pos = ( pos + ( ( len >> 1 ) & -64 ) );
#endif
              len = 64;
            }
            else
            {
              len = psh_dimension_quantize_len( dim, len, 0 );
            }
          }

          /* now that we have a good hinted stem width, try to position */
          /* the stem along a pixel grid integer coordinate             */
          hint->cur_pos = pos + psh_hint_snap_stem_side_delta( pos, len );
          hint->cur_len = len;
        }
      }

      if ( do_snapping )
      {
        pos = hint->cur_pos;
        len = hint->cur_len;

        if ( len < 64 )
          len = 64;
        else
          len = ( len + 32 ) & -64;

        switch ( align.align )
        {
          case PSH_BLUE_ALIGN_TOP:
            hint->cur_pos = align.align_top - len;
            hint->cur_len = len;
            break;

          case PSH_BLUE_ALIGN_BOT:
            hint->cur_len = len;
            break;

          case PSH_BLUE_ALIGN_BOT | PSH_BLUE_ALIGN_TOP:
            /* don't touch */
            break;


          default:
            hint->cur_len = len;
            if ( len & 64 )
              pos = ( ( pos + ( len >> 1 ) ) & -64 ) + 32;
            else
              pos = ( pos + ( len >> 1 ) + 32 ) & -64;

            hint->cur_pos = pos - ( len >> 1 );
            hint->cur_len = len;
        }
      }

      psh_hint_set_fitted( hint );

#ifdef DEBUG_HINTER
      if ( ps_debug_hint_func )
        ps_debug_hint_func( hint, dimension );
#endif
    }
  }


#if 0  /* not used for now, experimental */

 /*
  *  A variant to perform "light" hinting (i.e. FT_RENDER_MODE_LIGHT)
  *  of stems
  */
  static void
  psh_hint_align_light( PSH_Hint     hint,
                        PSH_Globals  globals,
                        FT_Int       dimension,
                        PSH_Glyph    glyph )
  {
    PSH_Dimension  dim   = &globals->dimension[dimension];
    FT_Fixed       scale = dim->scale_mult;
    FT_Fixed       delta = dim->scale_delta;


    if ( !psh_hint_is_fitted( hint ) )
    {
      FT_Pos  pos = FT_MulFix( hint->org_pos, scale ) + delta;
      FT_Pos  len = FT_MulFix( hint->org_len, scale );

      FT_Pos  fit_len;

      PSH_AlignmentRec  align;


      /* ignore stem alignments when requested through the hint flags */
      if ( ( dimension == 0 && !glyph->do_horz_hints ) ||
           ( dimension == 1 && !glyph->do_vert_hints ) )
      {
        hint->cur_pos = pos;
        hint->cur_len = len;

        psh_hint_set_fitted( hint );
        return;
      }

      fit_len = len;

      hint->cur_len = fit_len;

      /* check blue zones for horizontal stems */
      align.align = PSH_BLUE_ALIGN_NONE;
      align.align_bot = align.align_top = 0;

      if ( dimension == 1 )
        psh_blues_snap_stem( &globals->blues,
                             hint->org_pos + hint->org_len,
                             hint->org_pos,
                             &align );

      switch ( align.align )
      {
      case PSH_BLUE_ALIGN_TOP:
        /* the top of the stem is aligned against a blue zone */
        hint->cur_pos = align.align_top - fit_len;
        break;

      case PSH_BLUE_ALIGN_BOT:
        /* the bottom of the stem is aligned against a blue zone */
        hint->cur_pos = align.align_bot;
        break;

      case PSH_BLUE_ALIGN_TOP | PSH_BLUE_ALIGN_BOT:
        /* both edges of the stem are aligned against blue zones */
        hint->cur_pos = align.align_bot;
        hint->cur_len = align.align_top - align.align_bot;
        break;

      default:
        {
          PSH_Hint  parent = hint->parent;


          if ( parent )
          {
            FT_Pos  par_org_center, par_cur_center;
            FT_Pos  cur_org_center, cur_delta;


            /* ensure that parent is already fitted */
            if ( !psh_hint_is_fitted( parent ) )
              psh_hint_align_light( parent, globals, dimension, glyph );

            par_org_center = parent->org_pos + ( parent->org_len / 2 );
            par_cur_center = parent->cur_pos + ( parent->cur_len / 2 );
            cur_org_center = hint->org_pos   + ( hint->org_len   / 2 );

            cur_delta = FT_MulFix( cur_org_center - par_org_center, scale );
            pos       = par_cur_center + cur_delta - ( len >> 1 );
          }

          /* Stems less than one pixel wide are easy -- we want to
           * make them as dark as possible, so they must fall within
           * one pixel.  If the stem is split between two pixels
           * then snap the edge that is nearer to the pixel boundary
           * to the pixel boundary.
           */
          if ( len <= 64 )
          {
            if ( ( pos + len + 63 ) / 64  != pos / 64 + 1 )
              pos += psh_hint_snap_stem_side_delta ( pos, len );
          }

          /* Position stems other to minimize the amount of mid-grays.
           * There are, in general, two positions that do this,
           * illustrated as A) and B) below.
           *
           *   +                   +                   +                   +
           *
           * A)             |--------------------------------|
           * B)   |--------------------------------|
           * C)       |--------------------------------|
           *
           * Position A) (split the excess stem equally) should be better
           * for stems of width N + f where f < 0.5.
           *
           * Position B) (split the deficiency equally) should be better
           * for stems of width N + f where f > 0.5.
           *
           * It turns out though that minimizing the total number of lit
           * pixels is also important, so position C), with one edge
           * aligned with a pixel boundary is actually preferable
           * to A).  There are also more possibile positions for C) than
           * for A) or B), so it involves less distortion of the overall
           * character shape.
           */
          else /* len > 64 */
          {
            FT_Fixed  frac_len = len & 63;
            FT_Fixed  center = pos + ( len >> 1 );
            FT_Fixed  delta_a, delta_b;


            if ( ( len / 64 ) & 1 )
            {
              delta_a = ( center & -64 ) + 32 - center;
              delta_b = ( ( center + 32 ) & - 64 ) - center;
            }
            else
            {
              delta_a = ( ( center + 32 ) & - 64 ) - center;
              delta_b = ( center & -64 ) + 32 - center;
            }

            /* We choose between B) and C) above based on the amount
             * of fractinal stem width; for small amounts, choose
             * C) always, for large amounts, B) always, and inbetween,
             * pick whichever one involves less stem movement.
             */
            if ( frac_len < 32 )
            {
              pos += psh_hint_snap_stem_side_delta ( pos, len );
            }
            else if ( frac_len < 48 )
            {
              FT_Fixed  side_delta = psh_hint_snap_stem_side_delta ( pos,
                                                                     len );


              if ( ABS( side_delta ) < ABS( delta_b ) )
                pos += side_delta;
              else
                pos += delta_b;
            }
            else
            {
              pos += delta_b;
            }
          }

          hint->cur_pos = pos;
        }
      }  /* switch */

      psh_hint_set_fitted( hint );

#ifdef DEBUG_HINTER
      if ( ps_debug_hint_func )
        ps_debug_hint_func( hint, dimension );
#endif
    }
  }

#endif /* 0 */


  static void
  psh_hint_table_align_hints( PSH_Hint_Table  table,
                              PSH_Globals     globals,
                              FT_Int          dimension,
                              PSH_Glyph       glyph )
  {
    PSH_Hint       hint;
    FT_UInt        count;

#ifdef DEBUG_HINTER

    PSH_Dimension  dim   = &globals->dimension[dimension];
    FT_Fixed       scale = dim->scale_mult;
    FT_Fixed       delta = dim->scale_delta;


    if ( ps_debug_no_vert_hints && dimension == 0 )
    {
      ps_simple_scale( table, scale, delta, dimension );
      return;
    }

    if ( ps_debug_no_horz_hints && dimension == 1 )
    {
      ps_simple_scale( table, scale, delta, dimension );
      return;
    }

#endif /* DEBUG_HINTER*/

    hint  = table->hints;
    count = table->max_hints;

    for ( ; count > 0; count--, hint++ )
      psh_hint_align( hint, globals, dimension, glyph );
  }


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                POINTS INTERPOLATION ROUTINES                  *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

#define PSH_ZONE_MIN  -3200000L
#define PSH_ZONE_MAX  +3200000L

#define xxDEBUG_ZONES


#ifdef DEBUG_ZONES

#include <stdio.h>

  static void
  psh_print_zone( PSH_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 psh_print_zone( x )  do { } while ( 0 )

#endif /* DEBUG_ZONES */


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

#ifdef COMPUTE_INFLEXS

  /* compute all inflex points in a given glyph */
  static void
  psh_glyph_compute_inflections( PSH_Glyph  glyph )
  {
    FT_UInt  n;


    for ( n = 0; n < glyph->num_contours; n++ )
    {
      PSH_Point  first, start, end, before, after;
      FT_Angle   angle_in, angle_seg, angle_out;
      FT_Angle   diff_in, diff_out;
      FT_Int     finished = 0;


      /* we need at least 4 points to create an inflection point */
      if ( glyph->contours[n].count < 4 )
        continue;

      /* compute first segment in contour */
      first = glyph->contours[n].start;

      start = end = first;
      do
      {
        end = end->next;
        if ( end == first )
          goto Skip;

      } while ( PSH_POINT_EQUAL_ORG( end, first ) );

      angle_seg = PSH_POINT_ANGLE( start, end );

      /* extend the segment start whenever possible */
      before = start;
      do
      {
        do
        {
          start  = before;
          before = before->prev;
          if ( before == first )
            goto Skip;

        } while ( PSH_POINT_EQUAL_ORG( before, start ) );

        angle_in = PSH_POINT_ANGLE( before, start );

      } while ( angle_in == angle_seg );

      first   = start;
      diff_in = FT_Angle_Diff( angle_in, angle_seg );

      /* now, process all segments in the contour */
      do
      {
        /* first, extend current segment's end whenever possible */
        after = end;
        do
        {
          do
          {
            end   = after;
            after = after->next;
            if ( after == first )
              finished = 1;

          } while ( PSH_POINT_EQUAL_ORG( end, after ) );

          angle_out = PSH_POINT_ANGLE( end, after );

        } while ( angle_out == angle_seg );

        diff_out = FT_Angle_Diff( angle_seg, angle_out );

        if ( ( diff_in ^ diff_out ) < 0 )
        {
          /* diff_in and diff_out have different signs, we have */
          /* inflection points here...                          */

          do
          {
            psh_point_set_inflex( start );
            start = start->next;
          }
          while ( start != end );

          psh_point_set_inflex( start );
        }

        start     = end;
        end       = after;
        angle_seg = angle_out;
        diff_in   = diff_out;

      } while ( !finished );

    Skip:
      ;
    }
  }

#endif /* COMPUTE_INFLEXS */


  static void
  psh_glyph_done( PSH_Glyph  glyph )
  {
    FT_Memory  memory = glyph->memory;


    psh_hint_table_done( &glyph->hint_tables[1], memory );
    psh_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
  psh_compute_dir( FT_Pos  dx,
                   FT_Pos  dy )