pshalgo2.c

一个Xpdf应用的例子

/***************************************************************************/
/*                                                                         */
/*  pshalgo2.c                                                             */
/*                                                                         */
/*    PostScript hinting algorithm 2 (body).                               */
/*                                                                         */
/*  Copyright 2001 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 "pshalgo2.h"

#undef  FT_COMPONENT
#define FT_COMPONENT  trace_pshalgo2

#ifdef DEBUG_HINTER
  extern PSH2_Hint_Table  ps2_debug_hint_table = 0;
  extern PSH2_HintFunc    ps2_debug_hint_func  = 0;
  extern PSH2_Glyph       ps2_debug_glyph      = 0;
#endif


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

  /* return true iff two stem hints overlap */
  static FT_Int
  psh2_hint_overlap( PSH2_Hint  hint1,
                     PSH2_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
  psh2_hint_table_done( PSH2_Hint_Table  table,
                        FT_Memory        memory )
  {
    FREE( table->zones );
    table->num_zones = 0;
    table->zone      = 0;

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


  /* deactivate all hints in a table */
  static void
  psh2_hint_table_deactivate( PSH2_Hint_Table  table )
  {
    FT_UInt   count = table->max_hints;
    PSH2_Hint  hint  = table->hints;


    for ( ; count > 0; count--, hint++ )
    {
      psh2_hint_deactivate( hint );
      hint->order = -1;
    }
  }


  /* internal function used to record a new hint */
  static void
  psh2_hint_table_record( PSH2_Hint_Table  table,
                          FT_UInt          index )
  {
    PSH2_Hint  hint = table->hints + index;


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

    /* ignore active hints */
    if ( psh2_hint_is_active( hint ) )
      return;

    psh2_hint_activate( hint );

    /* now scan the current active hint set in order to determine */
    /* if we are overlapping with another segment                 */
    {
      PSH2_Hint*  sorted = table->sort_global;
      FT_UInt     count  = table->num_hints;
      PSH2_Hint   hint2;


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

        if ( psh2_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
  psh2_hint_table_record_mask( PSH2_Hint_Table  table,
                               PS_Mask          hint_mask )
  {
    FT_Int    mask = 0, val = 0;
    FT_Byte*  cursor = hint_mask->bytes;
    FT_UInt   index, limit;


    limit = hint_mask->num_bits;

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

      if ( val & mask )
        psh2_hint_table_record( table, index );

      mask >>= 1;
    }
  }


  /* create hints table */
  static FT_Error
  psh2_hint_table_init( PSH2_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 ( ALLOC_ARRAY( table->sort,  2 * count,     PSH2_Hint    ) ||
         ALLOC_ARRAY( table->hints,     count,     PSH2_HintRec ) ||
         ALLOC_ARRAY( table->zones, 2 * count + 1, PSH2_ZoneRec ) )
      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 */
    {
      PSH2_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++ )
        psh2_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++ )
        psh2_hint_table_record( table, Index );
    }

  Exit:
    return error;
  }


  static void
  psh2_hint_table_activate_mask( PSH2_Hint_Table  table,
                                 PS_Mask          hint_mask )
  {
    FT_Int    mask = 0, val = 0;
    FT_Byte*  cursor = hint_mask->bytes;
    FT_UInt   index, limit, count;


    limit = hint_mask->num_bits;
    count = 0;

    psh2_hint_table_deactivate( table );

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

      if ( val & mask )
      {
        PSH2_Hint  hint = &table->hints[index];


        if ( !psh2_hint_is_active( hint ) )
        {
          FT_UInt     count2;

#if 0
          PSH2_Hint*  sort = table->sort;
          PSH2_Hint   hint2;

          for ( count2 = count; count2 > 0; count2--, sort++ )
          {
            hint2 = sort[0];
            if ( psh2_hint_overlap( hint, hint2 ) )
              FT_ERROR(( "%s.activate_mask: found overlapping hints\n",
                         "psf.hint" ));
          }
#else
          count2 = 0;
#endif

          if ( count2 == 0 )
          {
            psh2_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;
      PSH2_Hint   hint1, hint2;
      PSH2_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
  static void
  ps2_simple_scale( PSH2_Hint_Table  table,
                    FT_Fixed         scale,
                    FT_Fixed         delta,
                    FT_Int           dimension )
  {
    PSH2_Hint  hint;
    FT_UInt    count;


    for ( count = 0; count < table->max_hints; count++ )
    {
      hint = table->hints + count;

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

      if ( ps2_debug_hint_func )
        ps2_debug_hint_func( hint, dimension );
    }
  }
#endif


  static void
  psh2_hint_align( PSH2_Hint    hint,
                   PSH_Globals  globals,
                   FT_Int       dimension )
  {
    PSH_Dimension  dim   = &globals->dimension[dimension];
    FT_Fixed       scale = dim->scale_mult;
    FT_Fixed       delta = dim->scale_delta;


    if ( !psh2_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_center;
      FT_Pos  fit_len;

      PSH_AlignmentRec  align;


      /* compute fitted width/height */
      fit_len = 0;
      if ( hint->org_len )
      {
        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 = 0;
      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:
        {
          PSH2_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 ( !psh2_hint_is_fitted( parent ) )
              psh2_hint_align( parent, globals, dimension );

            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 );
#if 0
            if ( cur_delta >= 0 )
              cur_delta = ( cur_delta + 16 ) & -64;
            else
              cur_delta = -( (-cur_delta + 16 ) & -64 );
#endif
            pos = par_cur_center + cur_delta - ( len >> 1 );
          }

          /* 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 );
        }
      }

      psh2_hint_set_fitted( hint );

#ifdef DEBUG_HINTER
      if ( ps2_debug_hint_func )
        ps2_debug_hint_func( hint, dimension );
#endif
    }
  }


  static void
  psh2_hint_table_align_hints( PSH2_Hint_Table  table,
                               PSH_Globals      globals,
                               FT_Int           dimension )
  {
    PSH2_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 )
    {
      ps2_simple_scale( table, scale, delta, dimension );
      return;
    }

    if ( ps_debug_no_horz_hints && dimension == 1 )
    {
      ps2_simple_scale( table, scale, delta, dimension );
      return;
    }
#endif

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

    for ( ; count > 0; count--, hint++ )
      psh2_hint_align( hint, globals, dimension );
  }


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

#define PSH2_ZONE_MIN  -3200000
#define PSH2_ZONE_MAX  +3200000

#define xxDEBUG_ZONES