shithub: purgatorio

ref: a8083462e62459b2ae8a243dc4ba88416eba03b1

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/***************************************************************************/
/*                                                                         */
/*  pshalgo1.c                                                             */
/*                                                                         */
/*    PostScript hinting algorithm 1 (body).                               */
/*                                                                         */
/*  Copyright 2001, 2002 by                                                */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used        */
/*  modified and distributed under the terms of the FreeType project       */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/


#include <ft2build.h>
#include FT_INTERNAL_OBJECTS_H
#include FT_INTERNAL_DEBUG_H
#include "pshalgo1.h"

#undef  FT_COMPONENT
#define FT_COMPONENT  trace_pshalgo1

#ifdef DEBUG_HINTER
  PSH1_Hint_Table  ps1_debug_hint_table = 0;
  PSH1_HintFunc    ps1_debug_hint_func  = 0;
#endif


 /************************************************************************/
 /************************************************************************/
 /*****                                                              *****/
 /*****                 BASIC HINTS RECORDINGS                       *****/
 /*****                                                              *****/
 /************************************************************************/
 /************************************************************************/

  /* return true iff two stem hints overlap */
  static FT_Int
  psh1_hint_overlap( PSH1_Hint  hint1,
                     PSH1_Hint  hint2 )
  {
    return ( hint1->org_pos + hint1->org_len >= hint2->org_pos &&
             hint2->org_pos + hint2->org_len >= hint1->org_pos );
  }


  /* destroy hints table */
  static void
  psh1_hint_table_done( PSH1_Hint_Table  table,
                        FT_Memory        memory )
  {
    FT_FREE( table->zones );
    table->num_zones = 0;
    table->zone      = 0;

    FT_FREE( table->sort );
    FT_FREE( table->hints );
    table->num_hints   = 0;
    table->max_hints   = 0;
    table->sort_global = 0;
  }


  /* deactivate all hints in a table */
  static void
  psh1_hint_table_deactivate( PSH1_Hint_Table  table )
  {
    FT_UInt    count = table->max_hints;
    PSH1_Hint  hint  = table->hints;


    for ( ; count > 0; count--, hint++ )
    {
      psh1_hint_deactivate( hint );
      hint->order = -1;
    }
  }


  /* internal function used to record a new hint */
  static void
  psh1_hint_table_record( PSH1_Hint_Table  table,
                          FT_UInt          idx )
  {
    PSH1_Hint  hint = table->hints + idx;


    if ( idx >= table->max_hints )
    {
      FT_ERROR(( "%s.activate: invalid hint index %d\n", idx ));
      return;
    }

    /* ignore active hints */
    if ( psh1_hint_is_active( hint ) )
      return;

    psh1_hint_activate( hint );

    /* now scan the current active hint set in order to determine */
    /* if we are overlapping with another segment                 */
    {
      PSH1_Hint*  sorted = table->sort_global;
      FT_UInt     count  = table->num_hints;
      PSH1_Hint   hint2;


      hint->parent = 0;
      for ( ; count > 0; count--, sorted++ )
      {
        hint2 = sorted[0];

        if ( psh1_hint_overlap( hint, hint2 ) )
        {
          hint->parent = hint2;
          break;
        }
      }
    }

    if ( table->num_hints < table->max_hints )
      table->sort_global[table->num_hints++] = hint;
    else
      FT_ERROR(( "%s.activate: too many sorted hints!  BUG!\n",
                 "ps.fitter" ));
  }


  static void
  psh1_hint_table_record_mask( PSH1_Hint_Table  table,
                               PS_Mask          hint_mask )
  {
    FT_Int    mask = 0, val = 0;
    FT_Byte*  cursor = hint_mask->bytes;
    FT_UInt   idx, limit;


    limit = hint_mask->num_bits;

    if ( limit != table->max_hints )
      FT_ERROR(( "%s.activate_mask: invalid bit count (%d instead of %d)\n",
                 "ps.fitter", hint_mask->num_bits, table->max_hints ));

    for ( idx = 0; idx < limit; idx++ )
    {
      if ( mask == 0 )
      {
        val  = *cursor++;
        mask = 0x80;
      }

      if ( val & mask )
        psh1_hint_table_record( table, idx );

      mask >>= 1;
    }
  }


  /* create hints table */
  static FT_Error
  psh1_hint_table_init( PSH1_Hint_Table  table,
                        PS_Hint_Table    hints,
                        PS_Mask_Table    hint_masks,
                        PS_Mask_Table    counter_masks,
                        FT_Memory        memory )
  {
    FT_UInt   count = hints->num_hints;
    FT_Error  error;

    FT_UNUSED( counter_masks );


    /* allocate our tables */
    if ( FT_NEW_ARRAY( table->sort,  2 * count     ) ||
         FT_NEW_ARRAY( table->hints,     count     ) ||
         FT_NEW_ARRAY( table->zones, 2 * count + 1 ) )
      goto Exit;

    table->max_hints   = count;
    table->sort_global = table->sort + count;
    table->num_hints   = 0;
    table->num_zones   = 0;
    table->zone        = 0;

    /* now, initialize the "hints" array */
    {
      PSH1_Hint  write = table->hints;
      PS_Hint    read  = hints->hints;


      for ( ; count > 0; count--, write++, read++ )
      {
        write->org_pos = read->pos;
        write->org_len = read->len;
        write->flags   = read->flags;
      }
    }

    /* we now need to determine the initial "parent" stems; first  */
    /* activate the hints that are given by the initial hint masks */
    if ( hint_masks )
    {
      FT_UInt  Count = hint_masks->num_masks;
      PS_Mask  Mask  = hint_masks->masks;


      table->hint_masks = hint_masks;

      for ( ; Count > 0; Count--, Mask++ )
        psh1_hint_table_record_mask( table, Mask );
    }

    /* now, do a linear parse in case some hints were left alone */
    if ( table->num_hints != table->max_hints )
    {
      FT_UInt   Index, Count;


      FT_ERROR(( "%s.init: missing/incorrect hint masks!\n" ));
      Count = table->max_hints;
      for ( Index = 0; Index < Count; Index++ )
        psh1_hint_table_record( table, Index );
    }

  Exit:
    return error;
  }


  static void
  psh1_hint_table_activate_mask( PSH1_Hint_Table  table,
                                 PS_Mask          hint_mask )
  {
    FT_Int    mask = 0, val = 0;
    FT_Byte*  cursor = hint_mask->bytes;
    FT_UInt   idx, limit, count;


    limit = hint_mask->num_bits;
    count = 0;

    psh1_hint_table_deactivate( table );

    for ( idx = 0; idx < limit; idx++ )
    {
      if ( mask == 0 )
      {
        val  = *cursor++;
        mask = 0x80;
      }

      if ( val & mask )
      {
        PSH1_Hint  hint = &table->hints[idx];


        if ( !psh1_hint_is_active( hint ) )
        {
          PSH1_Hint*  sort = table->sort;
          FT_UInt     count2;
          PSH1_Hint   hint2;


          for ( count2 = count; count2 > 0; count2--, sort++ )
          {
            hint2 = sort[0];
            if ( psh1_hint_overlap( hint, hint2 ) )
            {
              FT_ERROR(( "%s.activate_mask: found overlapping hints\n",
                         "psf.hint" ));
              break;
            }
          }

          if ( count2 == 0 )
          {
            psh1_hint_activate( hint );
            if ( count < table->max_hints )
              table->sort[count++] = hint;
            else
              FT_ERROR(( "%s.activate_mask: too many active hints\n",
                         "psf.hint" ));
          }
        }
      }

      mask >>= 1;
    }
    table->num_hints = count;

    /* now, sort the hints; they are guaranteed to not overlap */
    /* so we can compare their "org_pos" field directly        */
    {
      FT_Int      i1, i2;
      PSH1_Hint   hint1, hint2;
      PSH1_Hint*  sort = table->sort;


      /* a simple bubble sort will do, since in 99% of cases, the hints */
      /* will be already sorted; and the sort will be linear            */
      for ( i1 = 1; i1 < (FT_Int)count; i1++ )
      {
        hint1 = sort[i1];

        for ( i2 = i1 - 1; i2 >= 0; i2-- )
        {
          hint2 = sort[i2];
          if ( hint2->org_pos < hint1->org_pos )
            break;

          sort[i2 + 1] = hint2;
          sort[i2]     = hint1;
        }
      }
    }
  }


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****               HINTS GRID-FITTING AND OPTIMIZATION             *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

#ifdef DEBUG_HINTER
  void
  ps_simple_scale( PSH1_Hint_Table  table,
                   FT_Fixed         scale,
                   FT_Fixed         delta,
                   FT_Int           vertical )
  {
    PSH1_Hint  hint;
    FT_UInt    count;


    for ( count = 0; count < table->num_hints; count++ )
    {
      hint = table->sort[count];
      if ( psh1_hint_is_active( hint ) )
      {
        hint->cur_pos = FT_MulFix( hint->org_pos, scale ) + delta;
        hint->cur_len = FT_MulFix( hint->org_len, scale );

        if ( ps1_debug_hint_func )
          ps1_debug_hint_func( hint, vertical );
      }
    }
  }
#endif


  FT_LOCAL_DEF( FT_Error )
  psh1_hint_table_optimize( PSH1_Hint_Table  table,
                            PSH_Globals      globals,
                            FT_Outline*      outline,
                            FT_Int           vertical )
  {
    PSH_Dimension  dim   = &globals->dimension[vertical];
    FT_Fixed       scale = dim->scale_mult;
    FT_Fixed       delta = dim->scale_delta;

    FT_UNUSED( outline );


#ifdef DEBUG_HINTER
    if ( ps_debug_no_vert_hints && vertical )
    {
      ps_simple_scale( table, scale, delta, vertical );
      return 0;
    }

    if ( ps_debug_no_horz_hints && !vertical )
    {
      ps_simple_scale( table, scale, delta, vertical );
      return 0;
    }
#endif

    /* XXXX: for now, we only scale the hints to test all other aspects */
    /*       of the PostScript hinter                                   */
    {
      PSH1_Hint  hint;
      FT_UInt   count;


      for ( count = 0; count < table->num_hints; count++ )
      {
        hint = table->sort[count];
        if ( psh1_hint_is_active( hint ) )
        {
#if 1
          FT_Pos  pos = FT_MulFix( hint->org_pos, scale ) + delta;
          FT_Pos  len = FT_MulFix( hint->org_len, scale );

          FT_Pos  fit_center;
          FT_Pos  fit_len;

          PSH_AlignmentRec  align;


          /* compute fitted width/height */
          fit_len = psh_dimension_snap_width( dim, hint->org_len );
          if ( fit_len < 64 )
            fit_len = 64;
          else
            fit_len = ( fit_len + 32 ) & -64;

          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 ( !vertical )
          {
            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:
            /* normal processing */
            if ( ( fit_len / 64 ) & 1 )
            {
              /* odd number of pixels */
              fit_center = ( ( pos + ( len >> 1 ) ) & -64 ) + 32;
            }
            else
            {
              /* even number of pixels */
              fit_center = ( pos + ( len >> 1 ) + 32 ) & -64;
            }

            hint->cur_pos = fit_center - ( fit_len >> 1 );
          }

# else

          hint->cur_pos = ( FT_MulFix( hint->org_pos, scale ) + delta + 32 )
                          & -64;
          hint->cur_len = FT_MulFix( hint->org_len, scale );

# endif

#ifdef DEBUG_HINTER
        if ( ps1_debug_hint_func )
          ps1_debug_hint_func( hint, vertical );
#endif
        }
      }
    }

    return 0;
  }


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

#define PSH1_ZONE_MIN  -3200000
#define PSH1_ZONE_MAX  +3200000

#define xxDEBUG_ZONES


#ifdef DEBUG_ZONES

#include <stdio.h>

  static void
  psh1_print_zone( PSH1_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 psh1_print_zone( x )  do { } while ( 0 )
#endif

  /* setup interpolation zones once the hints have been grid-fitted */
  /* by the optimizer                                               */
  static void
  psh1_hint_table_setup_zones( PSH1_Hint_Table  table,
                               FT_Fixed         scale,
                               FT_Fixed         delta )
  {
    FT_UInt     count;
    PSH1_Zone   zone;
    PSH1_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   = PSH1_ZONE_MIN;
      zone->max   = PSH1_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   = PSH1_ZONE_MIN;
    zone->max   = hint->org_pos;

    psh1_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 );

        psh1_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 );

      psh1_print_zone( zone );

      zone++;

      hint = hint2;
    }

    /* the last zone */
    zone->scale = scale;
    zone->min   = hint->org_pos + hint->org_len;
    zone->max   = PSH1_ZONE_MAX;
    zone->delta = hint->cur_pos + hint->cur_len -
                  FT_MulFix( zone->min, scale );

    psh1_print_zone( zone );

    zone++;

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


  /* tune a single coordinate with the current interpolation zones */
  static FT_Pos
  psh1_hint_table_tune_coord( PSH1_Hint_Table  table,
                              FT_Int           coord )
  {
    PSH1_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;
  }


  /* tune a given outline with current interpolation zones. */
  /* The function only works in a single dimension.         */
  static void
  psh1_hint_table_tune_outline( PSH1_Hint_Table  table,
                                FT_Outline*      outline,
                                PSH_Globals      globals,
                                FT_Int           vertical )

  {
    FT_UInt         count, first, last;
    PS_Mask_Table   hint_masks = table->hint_masks;
    PS_Mask         mask;
    PSH_Dimension   dim        = &globals->dimension[vertical];
    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;


          psh1_hint_table_activate_mask( table, mask );
          psh1_hint_table_optimize( table, globals, outline, vertical );
          psh1_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  = vertical ? &vec->x : &vec->y;
            x   = *px;

            *px = psh1_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 ( vertical )
      {
        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;
      }
    }
  }


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                     HIGH-LEVEL INTERFACE                      *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  FT_Error
  ps1_hints_apply( PS_Hints        ps_hints,
                   FT_Outline*     outline,
                   PSH_Globals     globals,
                   FT_Render_Mode  hint_mode )
  {
    PSH1_Hint_TableRec  hints;
    FT_Error            error = 0;
    FT_Int              dimension;


    FT_UNUSED( hint_mode );

    for ( dimension = 1; dimension >= 0; dimension-- )
    {
      PS_Dimension  dim = &ps_hints->dimension[dimension];


      /* initialize hints table */
      FT_MEM_ZERO( &hints, sizeof ( hints ) );
      error = psh1_hint_table_init( &hints,
                                    &dim->hints,
                                    &dim->masks,
                                    &dim->counters,
                                    ps_hints->memory );
      if ( error )
        goto Exit;

      psh1_hint_table_tune_outline( &hints,
                                    outline,
                                    globals,
                                    dimension );

      psh1_hint_table_done( &hints, ps_hints->memory );
    }

  Exit:
    return error;
  }


/* END */