afhints.c

智能设备中PDF阅读器的源码！用于windows mobile2003或者WM5以上

/***************************************************************************/
/*                                                                         */
/*  afhints.c                                                              */
/*                                                                         */
/*    Auto-fitter hinting routines (body).                                 */
/*                                                                         */
/*  Copyright 2003, 2004, 2005, 2006 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 "afhints.h"
#include "aferrors.h"


  FT_LOCAL_DEF( FT_Error )
  af_axis_hints_new_segment( AF_AxisHints  axis,
                             FT_Memory     memory,
                             AF_Segment   *asegment )
  {
    FT_Error    error   = AF_Err_Ok;
    AF_Segment  segment = NULL;


    if ( axis->num_segments >= axis->max_segments )
    {
      FT_Int  old_max = axis->max_segments;
      FT_Int  new_max = old_max;
      FT_Int  big_max = FT_INT_MAX / sizeof ( *segment );


      if ( old_max >= big_max )
      {
        error = AF_Err_Out_Of_Memory;
        goto Exit;
      }

      new_max += ( new_max >> 2 ) + 4;
      if ( new_max < old_max || new_max > big_max )
        new_max = big_max;

      if ( FT_RENEW_ARRAY( axis->segments, old_max, new_max ) )
        goto Exit;

      axis->max_segments = new_max;
    }

    segment = axis->segments + axis->num_segments++;
    FT_ZERO( segment );

  Exit:
    *asegment = segment;
    return error;
  }


  FT_LOCAL( FT_Error )
  af_axis_hints_new_edge( AF_AxisHints  axis,
                          FT_Int        fpos,
                          FT_Memory     memory,
                          AF_Edge      *aedge )
  {
    FT_Error  error = AF_Err_Ok;
    AF_Edge   edge  = NULL;
    AF_Edge   edges;


    if ( axis->num_edges >= axis->max_edges )
    {
      FT_Int  old_max = axis->max_edges;
      FT_Int  new_max = old_max;
      FT_Int  big_max = FT_INT_MAX / sizeof ( *edge );


      if ( old_max >= big_max )
      {
        error = AF_Err_Out_Of_Memory;
        goto Exit;
      }

      new_max += ( new_max >> 2 ) + 4;
      if ( new_max < old_max || new_max > big_max )
        new_max = big_max;

      if ( FT_RENEW_ARRAY( axis->edges, old_max, new_max ) )
        goto Exit;

      axis->max_edges = new_max;
    }

    edges = axis->edges;
    edge  = edges + axis->num_edges;

    while ( edge > edges && edge[-1].fpos > fpos )
    {
      edge[0] = edge[-1];
      edge--;
    }

    axis->num_edges++;

    FT_ZERO( edge );
    edge->fpos = (FT_Short)fpos;

  Exit:
    *aedge = edge;
    return error;
  }


#ifdef AF_DEBUG

#include <stdio.h>

  static const char*
  af_dir_str( AF_Direction  dir )
  {
    const char*  result;


    switch ( dir )
    {
    case AF_DIR_UP:
      result = "up";
      break;
    case AF_DIR_DOWN:
      result = "down";
      break;
    case AF_DIR_LEFT:
      result = "left";
      break;
    case AF_DIR_RIGHT:
      result = "right";
      break;
    default:
      result = "none";
    }

    return result;
  }


#define AF_INDEX_NUM( ptr, base )  ( (ptr) ? ( (ptr) - (base) ) : -1 )


  void
  af_glyph_hints_dump_points( AF_GlyphHints  hints )
  {
    AF_Point  points = hints->points;
    AF_Point  limit  = points + hints->num_points;
    AF_Point  point;


    printf( "Table of points:\n" );
    printf(   "  [ index |  xorg |  yorg |  xscale |  yscale "
              "|  xfit  |  yfit  |  flags ]\n" );

    for ( point = points; point < limit; point++ )
    {
      printf( "  [ %5d | %5d | %5d | %-5.2f | %-5.2f "
              "| %-5.2f | %-5.2f | %c%c%c%c%c%c ]\n",
              point - points,
              point->fx,
              point->fy,
              point->ox/64.0,
              point->oy/64.0,
              point->x/64.0,
              point->y/64.0,
              ( point->flags & AF_FLAG_WEAK_INTERPOLATION ) ? 'w' : ' ',
              ( point->flags & AF_FLAG_INFLECTION )         ? 'i' : ' ',
              ( point->flags & AF_FLAG_EXTREMA_X )          ? '<' : ' ',
              ( point->flags & AF_FLAG_EXTREMA_Y )          ? 'v' : ' ',
              ( point->flags & AF_FLAG_ROUND_X )            ? '(' : ' ',
              ( point->flags & AF_FLAG_ROUND_Y )            ? 'u' : ' ');
    }
    printf( "\n" );
  }


  /* A function to dump the array of linked segments. */
  void
  af_glyph_hints_dump_segments( AF_GlyphHints  hints )
  {
    AF_Point  points = hints->points;
    FT_Int    dimension;


    for ( dimension = 1; dimension >= 0; dimension-- )
    {
      AF_AxisHints  axis     = &hints->axis[dimension];
      AF_Segment    segments = axis->segments;
      AF_Segment    limit    = segments + axis->num_segments;
      AF_Segment    seg;


      printf ( "Table of %s segments:\n",
               dimension == AF_DIMENSION_HORZ ? "vertical" : "horizontal" );
      printf ( "  [ index |  pos |  dir  | link | serif |"
               " numl | first | start ]\n" );

      for ( seg = segments; seg < limit; seg++ )
      {
        printf ( "  [ %5d | %4d | %5s | %4d | %5d | %4d | %5d | %5d ]\n",
                 seg - segments,
                 (int)seg->pos,
                 af_dir_str( seg->dir ),
                 AF_INDEX_NUM( seg->link, segments ),
                 AF_INDEX_NUM( seg->serif, segments ),
                 (int)seg->num_linked,
                 seg->first - points,
                 seg->last - points );
      }
      printf( "\n" );
    }
  }


  void
  af_glyph_hints_dump_edges( AF_GlyphHints  hints )
  {
    FT_Int  dimension;


    for ( dimension = 1; dimension >= 0; dimension-- )
    {
      AF_AxisHints  axis  = &hints->axis[dimension];
      AF_Edge       edges = axis->edges;
      AF_Edge       limit = edges + axis->num_edges;
      AF_Edge       edge;


      /*
       *  note: AF_DIMENSION_HORZ corresponds to _vertical_ edges
       *        since they have constant a X coordinate.
       */
      printf ( "Table of %s edges:\n",
               dimension == AF_DIMENSION_HORZ ? "vertical" : "horizontal" );
      printf ( "  [ index |  pos |  dir  | link |"
               " serif | blue | opos  |  pos  ]\n" );

      for ( edge = edges; edge < limit; edge++ )
      {
        printf ( "  [ %5d | %4d | %5s | %4d |"
                 " %5d |   %c  | %5.2f | %5.2f ]\n",
                 edge - edges,
                 (int)edge->fpos,
                 af_dir_str( edge->dir ),
                 AF_INDEX_NUM( edge->link, edges ),
                 AF_INDEX_NUM( edge->serif, edges ),
                 edge->blue_edge ? 'y' : 'n',
                 edge->opos / 64.0,
                 edge->pos / 64.0 );
      }
      printf( "\n" );
    }
  }

#endif /* AF_DEBUG */



  /* compute the direction value of a given vector */
  FT_LOCAL_DEF( AF_Direction )
  af_direction_compute( FT_Pos  dx,
                        FT_Pos  dy )
  {
#if 1
    AF_Direction  dir = AF_DIR_NONE;


    /* atan(1/12) == 4.7 degrees */

    if ( dx < 0 )
    {
      if ( dy < 0 )
      {
        if ( -dx * 12 < -dy )
          dir = AF_DIR_DOWN;

        else if ( -dy * 12 < -dx )
          dir = AF_DIR_LEFT;
      }
      else /* dy >= 0 */
      {
        if ( -dx * 12 < dy )
          dir = AF_DIR_UP;

        else if ( dy * 12 < -dx )
          dir = AF_DIR_LEFT;
      }
    }
    else /* dx >= 0 */
    {
      if ( dy < 0 )
      {
        if ( dx * 12 < -dy )
          dir = AF_DIR_DOWN;

        else if ( -dy * 12 < dx )
          dir = AF_DIR_RIGHT;
      }
      else  /* dy >= 0 */
      {
        if ( dx * 12 < dy )
          dir = AF_DIR_UP;

        else if ( dy * 12 < dx )
          dir = AF_DIR_RIGHT;
      }
    }

    return dir;

#else /* 0 */

    AF_Direction  dir;
    FT_Pos        ax = FT_ABS( dx );
    FT_Pos        ay = FT_ABS( dy );


    dir = AF_DIR_NONE;

    /* atan(1/12) == 4.7 degrees */

    /* test for vertical direction */
    if ( ax * 12 < ay )
    {
      dir = dy > 0 ? AF_DIR_UP : AF_DIR_DOWN;
    }
    /* test for horizontal direction */
    else if ( ay * 12 < ax )
    {
      dir = dx > 0 ? AF_DIR_RIGHT : AF_DIR_LEFT;
    }

    return dir;

#endif /* 0 */

  }


  /* compute all inflex points in a given glyph */
  static void
  af_glyph_hints_compute_inflections( AF_GlyphHints  hints )
  {
    AF_Point*  contour       = hints->contours;
    AF_Point*  contour_limit = contour + hints->num_contours;


    /* do each contour separately */
    for ( ; contour < contour_limit; contour++ )
    {
      AF_Point  point = contour[0];
      AF_Point  first = point;
      AF_Point  start = point;
      AF_Point  end   = point;
      AF_Point  before;
      AF_Point  after;
      AF_Angle  angle_in, angle_seg, angle_out;
      AF_Angle  diff_in, diff_out;
      FT_Int    finished = 0;


      /* compute first segment in contour */
      first = point;

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

      } while ( end->fx == first->fx && end->fy == first->fy );

      angle_seg = af_angle_atan( end->fx - start->fx,
                                 end->fy - start->fy );

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

        } while ( before->fx == start->fx && before->fy == start->fy );

        angle_in = af_angle_atan( start->fx - before->fx,
                                  start->fy - before->fy );

      } while ( angle_in == angle_seg );

      first = start;

      AF_ANGLE_DIFF( diff_in, 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 ( end->fx == after->fx && end->fy == after->fy );

          angle_out = af_angle_atan( after->fx - end->fx,
                                     after->fy - end->fy );

        } while ( angle_out == angle_seg );

        AF_ANGLE_DIFF( diff_out, angle_seg, angle_out );

        if ( ( diff_in ^ diff_out ) < 0 )
        {
          /* diff_in and diff_out have different signs, we have */
          /* inflection points here...                          */
          do
          {
            start->flags |= AF_FLAG_INFLECTION;
            start = start->next;

          } while ( start != end );

          start->flags |= AF_FLAG_INFLECTION;
        }

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

      } while ( !finished );

    Skip:
      ;
    }
  }


  FT_LOCAL_DEF( void )
  af_glyph_hints_init( AF_GlyphHints  hints,
                       FT_Memory      memory )
  {
    FT_ZERO( hints );
    hints->memory = memory;
  }


  FT_LOCAL_DEF( void )
  af_glyph_hints_done( AF_GlyphHints  hints )
  {
    if ( hints && hints->memory )
    {
      FT_Memory  memory = hints->memory;
      int        dim;


      /*
       *  note that we don't need to free the segment and edge
       *  buffers, since they are really within the hints->points array
       */
      for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
      {
        AF_AxisHints  axis = &hints->axis[dim];


        axis->num_segments = 0;
        axis->max_segments = 0;
        FT_FREE( axis->segments );

        axis->num_edges    = 0;
        axis->max_edges    = 0;
        FT_FREE( axis->edges );
      }

      FT_FREE( hints->contours );
      hints->max_contours = 0;
      hints->num_contours = 0;

      FT_FREE( hints->points );
      hints->num_points = 0;
      hints->max_points = 0;

      hints->memory = NULL;
    }
  }


  FT_LOCAL_DEF( void )
  af_glyph_hints_rescale( AF_GlyphHints     hints,
                          AF_ScriptMetrics  metrics )
  {
    hints->metrics      = metrics;
    hints->scaler_flags = metrics->scaler.flags;
  }


  FT_LOCAL_DEF( FT_Error )
  af_glyph_hints_reload( AF_GlyphHints  hints,
                         FT_Outline*    outline )
  {
    FT_Error   error   = AF_Err_Ok;
    AF_Point   points;
    FT_UInt    old_max, new_max;
    FT_Fixed   x_scale = hints->x_scale;
    FT_Fixed   y_scale = hints->y_scale;
    FT_Pos     x_delta = hints->x_delta;
    FT_Pos     y_delta = hints->y_delta;
    FT_Memory  memory  = hints->memory;


    hints->num_points   = 0;
    hints->num_contours = 0;

    hints->axis[0].num_segments = 0;
    hints->axis[0].num_edges    = 0;
    hints->axis[1].num_segments = 0;
    hints->axis[1].num_edges    = 0;

    /* first of all, reallocate the contours array when necessary */
    new_max = (FT_UInt)outline->n_contours;
    old_max = hints->max_contours;
    if ( new_max > old_max )
    {
      new_max = ( new_max + 3 ) & ~3;

      if ( FT_RENEW_ARRAY( hints->contours, old_max, new_max ) )
        goto Exit;

      hints->max_contours = new_max;
    }

    /*
     *  then reallocate the points arrays if necessary --
     *  note that we reserve two additional point positions, used to
     *  hint metrics appropriately
     */
    new_max = (FT_UInt)( outline->n_points + 2 );
    old_max = hints->max_points;
    if ( new_max > old_max )
    {
      new_max = ( new_max + 2 + 7 ) & ~7;

      if ( FT_RENEW_ARRAY( hints->points, old_max, new_max ) )
        goto Exit;

      hints->max_points = new_max;
    }

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

    /* We can't rely on the value of `FT_Outline.flags' to know the fill   */
    /* direction used for a glyph, given that some fonts are broken (e.g., */
    /* the Arphic ones).  We thus recompute it each time we need to.       */
    /*                                                                     */
    hints->axis[AF_DIMENSION_HORZ].major_dir = AF_DIR_UP;
    hints->axis[AF_DIMENSION_VERT].major_dir = AF_DIR_LEFT;

    if ( FT_Outline_Get_Orientation( outline ) == FT_ORIENTATION_POSTSCRIPT )
    {
      hints->axis[AF_DIMENSION_HORZ].major_dir = AF_DIR_DOWN;
      hints->axis[AF_DIMENSION_VERT].major_dir = AF_DIR_RIGHT;
    }

    hints->x_scale = x_scale;
    hints->y_scale = y_scale;