misc/libfreetype/src/autofit/afhints.c
changeset 5172 88f2e05288ba
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/misc/libfreetype/src/autofit/afhints.c	Mon Apr 25 01:46:54 2011 +0200
@@ -0,0 +1,1208 @@
+/***************************************************************************/
+/*                                                                         */
+/*  afhints.c                                                              */
+/*                                                                         */
+/*    Auto-fitter hinting routines (body).                                 */
+/*                                                                         */
+/*  Copyright 2003-2007, 2009-2011 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"
+#include FT_INTERNAL_CALC_H
+
+
+  /* Get new segment for given axis. */
+
+  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)( 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++;
+
+  Exit:
+    *asegment = segment;
+    return error;
+  }
+
+
+  /* Get new edge for given axis, direction, and position. */
+
+  FT_LOCAL( FT_Error )
+  af_axis_hints_new_edge( AF_AxisHints  axis,
+                          FT_Int        fpos,
+                          AF_Direction  dir,
+                          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)( 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 )
+    {
+      if ( edge[-1].fpos < fpos )
+        break;
+
+      /* we want the edge with same position and minor direction */
+      /* to appear before those in the major one in the list     */
+      if ( edge[-1].fpos == fpos && dir == axis->major_dir )
+        break;
+
+      edge[0] = edge[-1];
+      edge--;
+    }
+
+    axis->num_edges++;
+
+    FT_ZERO( edge );
+    edge->fpos = (FT_Short)fpos;
+    edge->dir  = (FT_Char)dir;
+
+  Exit:
+    *aedge = edge;
+    return error;
+  }
+
+
+#ifdef FT_DEBUG_AUTOFIT
+
+#include FT_CONFIG_STANDARD_LIBRARY_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 )
+
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+  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 | %6.2f | %6.2f"
+              " | %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" );
+  }
+#ifdef __cplusplus
+  }
+#endif
+
+
+  static const char*
+  af_edge_flags_to_string( AF_Edge_Flags  flags )
+  {
+    static char  temp[32];
+    int          pos = 0;
+
+
+    if ( flags & AF_EDGE_ROUND )
+    {
+      ft_memcpy( temp + pos, "round", 5 );
+      pos += 5;
+    }
+    if ( flags & AF_EDGE_SERIF )
+    {
+      if ( pos > 0 )
+        temp[pos++] = ' ';
+      ft_memcpy( temp + pos, "serif", 5 );
+      pos += 5;
+    }
+    if ( pos == 0 )
+      return "normal";
+
+    temp[pos] = 0;
+
+    return temp;
+  }
+
+
+  /* Dump the array of linked segments. */
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+  void
+  af_glyph_hints_dump_segments( AF_GlyphHints  hints )
+  {
+    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 |"
+               " height | extra |    flags    ]\n" );
+
+      for ( seg = segments; seg < limit; seg++ )
+      {
+        printf ( "  [ %5d | %5.2g | %5s | %4d | %5d | %6d | %5d | %11s ]\n",
+                 seg - segments,
+                 dimension == AF_DIMENSION_HORZ ? (int)seg->first->ox / 64.0
+                                                : (int)seg->first->oy / 64.0,
+                 af_dir_str( (AF_Direction)seg->dir ),
+                 AF_INDEX_NUM( seg->link, segments ),
+                 AF_INDEX_NUM( seg->serif, segments ),
+                 seg->height,
+                 seg->height - ( seg->max_coord - seg->min_coord ),
+                 af_edge_flags_to_string( seg->flags ) );
+      }
+      printf( "\n" );
+    }
+  }
+#ifdef __cplusplus
+  }
+#endif
+
+
+  /* Dump the array of linked edges. */
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+  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 a constant X coordinate.
+       */
+      printf ( "Table of %s edges:\n",
+               dimension == AF_DIMENSION_HORZ ? "vertical" : "horizontal" );
+      printf ( "  [ index |  pos  |  dir  | link |"
+               " serif | blue | opos  |  pos  |    flags    ]\n" );
+
+      for ( edge = edges; edge < limit; edge++ )
+      {
+        printf ( "  [ %5d | %5.2g | %5s | %4d |"
+                 " %5d |   %c  | %5.2f | %5.2f | %11s ]\n",
+                 edge - edges,
+                 (int)edge->opos / 64.0,
+                 af_dir_str( (AF_Direction)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,
+                 af_edge_flags_to_string( edge->flags ) );
+      }
+      printf( "\n" );
+    }
+  }
+#ifdef __cplusplus
+  }
+#endif
+
+#else /* !FT_DEBUG_AUTOFIT */
+
+  /* these empty stubs are only used to link the `ftgrid' test program */
+  /* if debugging is disabled                                          */
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+  void
+  af_glyph_hints_dump_points( AF_GlyphHints  hints )
+  {
+    FT_UNUSED( hints );
+  }
+
+
+  void
+  af_glyph_hints_dump_segments( AF_GlyphHints  hints )
+  {
+    FT_UNUSED( hints );
+  }
+
+
+  void
+  af_glyph_hints_dump_edges( AF_GlyphHints  hints )
+  {
+    FT_UNUSED( hints );
+  }
+
+#ifdef __cplusplus
+  }
+#endif
+
+#endif /* !FT_DEBUG_AUTOFIT */
+
+
+  /* Compute the direction value of a given vector. */
+
+  FT_LOCAL_DEF( AF_Direction )
+  af_direction_compute( FT_Pos  dx,
+                        FT_Pos  dy )
+  {
+    FT_Pos        ll, ss;  /* long and short arm lengths */
+    AF_Direction  dir;     /* candidate direction        */
+
+
+    if ( dy >= dx )
+    {
+      if ( dy >= -dx )
+      {
+        dir = AF_DIR_UP;
+        ll  = dy;
+        ss  = dx;
+      }
+      else
+      {
+        dir = AF_DIR_LEFT;
+        ll  = -dx;
+        ss  = dy;
+      }
+    }
+    else /* dy < dx */
+    {
+      if ( dy >= -dx )
+      {
+        dir = AF_DIR_RIGHT;
+        ll  = dx;
+        ss  = dy;
+      }
+      else
+      {
+        dir = AF_DIR_DOWN;
+        ll  = dy;
+        ss  = dx;
+      }
+    }
+
+    /* return no direction if arm lengths differ too much */
+    /* (value 14 is heuristic)                            */
+    ss *= 14;
+    if ( FT_ABS( ll ) <= FT_ABS( ss ) )
+      dir = AF_DIR_NONE;
+
+    return dir;
+  }
+
+
+  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;
+    }
+  }
+
+
+  /* Reset metrics. */
+
+  FT_LOCAL_DEF( void )
+  af_glyph_hints_rescale( AF_GlyphHints     hints,
+                          AF_ScriptMetrics  metrics )
+  {
+    hints->metrics      = metrics;
+    hints->scaler_flags = metrics->scaler.flags;
+  }
+
+
+  /* Recompute all AF_Point in AF_GlyphHints from the definitions */
+  /* in a source outline.                                         */
+
+  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 if necessary */
+    new_max = (FT_UInt)outline->n_contours;
+    old_max = hints->max_contours;
+    if ( new_max > old_max )
+    {
+      new_max = ( new_max + 3 ) & ~3; /* round up to a multiple of 4 */
+
+      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; /* round up to a multiple of 8 */
+
+      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;
+    hints->x_delta = x_delta;
+    hints->y_delta = y_delta;
+
+    hints->xmin_delta = 0;
+    hints->xmax_delta = 0;
+
+    points = hints->points;
+    if ( hints->num_points == 0 )
+      goto Exit;
+
+    {
+      AF_Point  point;
+      AF_Point  point_limit = points + hints->num_points;
+
+
+      /* compute coordinates & Bezier flags, next and prev */
+      {
+        FT_Vector*  vec           = outline->points;
+        char*       tag           = outline->tags;
+        AF_Point    end           = points + outline->contours[0];
+        AF_Point    prev          = end;
+        FT_Int      contour_index = 0;
+
+
+        for ( point = points; point < point_limit; point++, vec++, tag++ )
+        {
+          point->fx = (FT_Short)vec->x;
+          point->fy = (FT_Short)vec->y;
+          point->ox = point->x = FT_MulFix( vec->x, x_scale ) + x_delta;
+          point->oy = point->y = FT_MulFix( vec->y, y_scale ) + y_delta;
+
+          switch ( FT_CURVE_TAG( *tag ) )
+          {
+          case FT_CURVE_TAG_CONIC:
+            point->flags = AF_FLAG_CONIC;
+            break;
+          case FT_CURVE_TAG_CUBIC:
+            point->flags = AF_FLAG_CUBIC;
+            break;
+          default:
+            point->flags = AF_FLAG_NONE;
+          }
+
+          point->prev = prev;
+          prev->next  = point;
+          prev        = point;
+
+          if ( point == end )
+          {
+            if ( ++contour_index < outline->n_contours )
+            {
+              end  = points + outline->contours[contour_index];
+              prev = end;
+            }
+          }
+        }
+      }
+
+      /* set up the contours array */
+      {
+        AF_Point*  contour       = hints->contours;
+        AF_Point*  contour_limit = contour + hints->num_contours;
+        short*     end           = outline->contours;
+        short      idx           = 0;
+
+
+        for ( ; contour < contour_limit; contour++, end++ )
+        {
+          contour[0] = points + idx;
+          idx        = (short)( end[0] + 1 );
+        }
+      }
+
+      /* compute directions of in & out vectors */
+      {
+        AF_Point      first  = points;
+        AF_Point      prev   = NULL;
+        FT_Pos        in_x   = 0;
+        FT_Pos        in_y   = 0;
+        AF_Direction  in_dir = AF_DIR_NONE;
+
+
+        for ( point = points; point < point_limit; point++ )
+        {
+          AF_Point  next;
+          FT_Pos    out_x, out_y;
+
+
+          if ( point == first )
+          {
+            prev   = first->prev;
+            in_x   = first->fx - prev->fx;
+            in_y   = first->fy - prev->fy;
+            in_dir = af_direction_compute( in_x, in_y );
+            first  = prev + 1;
+          }
+
+          point->in_dir = (FT_Char)in_dir;
+
+          next  = point->next;
+          out_x = next->fx - point->fx;
+          out_y = next->fy - point->fy;
+
+          in_dir         = af_direction_compute( out_x, out_y );
+          point->out_dir = (FT_Char)in_dir;
+
+          /* check for weak points */
+
+          if ( point->flags & ( AF_FLAG_CONIC | AF_FLAG_CUBIC ) )
+          {
+          Is_Weak_Point:
+            point->flags |= AF_FLAG_WEAK_INTERPOLATION;
+          }
+          else if ( point->out_dir == point->in_dir )
+          {
+            if ( point->out_dir != AF_DIR_NONE )
+              goto Is_Weak_Point;
+
+            if ( ft_corner_is_flat( in_x, in_y, out_x, out_y ) )
+              goto Is_Weak_Point;
+          }
+          else if ( point->in_dir == -point->out_dir )
+            goto Is_Weak_Point;
+
+          in_x = out_x;
+          in_y = out_y;
+          prev = point;
+        }
+      }
+    }
+
+  Exit:
+    return error;
+  }
+
+
+  /* Store the hinted outline in an FT_Outline structure. */
+
+  FT_LOCAL_DEF( void )
+  af_glyph_hints_save( AF_GlyphHints  hints,
+                       FT_Outline*    outline )
+  {
+    AF_Point    point = hints->points;
+    AF_Point    limit = point + hints->num_points;
+    FT_Vector*  vec   = outline->points;
+    char*       tag   = outline->tags;
+
+
+    for ( ; point < limit; point++, vec++, tag++ )
+    {
+      vec->x = point->x;
+      vec->y = point->y;
+
+      if ( point->flags & AF_FLAG_CONIC )
+        tag[0] = FT_CURVE_TAG_CONIC;
+      else if ( point->flags & AF_FLAG_CUBIC )
+        tag[0] = FT_CURVE_TAG_CUBIC;
+      else
+        tag[0] = FT_CURVE_TAG_ON;
+    }
+  }
+
+
+  /****************************************************************
+   *
+   *                     EDGE POINT GRID-FITTING
+   *
+   ****************************************************************/
+
+
+  /* Align all points of an edge to the same coordinate value, */
+  /* either horizontally or vertically.                        */
+
+  FT_LOCAL_DEF( void )
+  af_glyph_hints_align_edge_points( AF_GlyphHints  hints,
+                                    AF_Dimension   dim )
+  {
+    AF_AxisHints  axis          = & hints->axis[dim];
+    AF_Segment    segments      = axis->segments;
+    AF_Segment    segment_limit = segments + axis->num_segments;
+    AF_Segment    seg;
+
+
+    if ( dim == AF_DIMENSION_HORZ )
+    {
+      for ( seg = segments; seg < segment_limit; seg++ )
+      {
+        AF_Edge   edge = seg->edge;
+        AF_Point  point, first, last;
+
+
+        if ( edge == NULL )
+          continue;
+
+        first = seg->first;
+        last  = seg->last;
+        point = first;
+        for (;;)
+        {
+          point->x      = edge->pos;
+          point->flags |= AF_FLAG_TOUCH_X;
+
+          if ( point == last )
+            break;
+
+          point = point->next;
+        }
+      }
+    }
+    else
+    {
+      for ( seg = segments; seg < segment_limit; seg++ )
+      {
+        AF_Edge   edge = seg->edge;
+        AF_Point  point, first, last;
+
+
+        if ( edge == NULL )
+          continue;
+
+        first = seg->first;
+        last  = seg->last;
+        point = first;
+        for (;;)
+        {
+          point->y      = edge->pos;
+          point->flags |= AF_FLAG_TOUCH_Y;
+
+          if ( point == last )
+            break;
+
+          point = point->next;
+        }
+      }
+    }
+  }
+
+
+  /****************************************************************
+   *
+   *                    STRONG POINT INTERPOLATION
+   *
+   ****************************************************************/
+
+
+  /* Hint the strong points -- this is equivalent to the TrueType `IP' */
+  /* hinting instruction.                                              */
+
+  FT_LOCAL_DEF( void )
+  af_glyph_hints_align_strong_points( AF_GlyphHints  hints,
+                                      AF_Dimension   dim )
+  {
+    AF_Point      points      = hints->points;
+    AF_Point      point_limit = points + hints->num_points;
+    AF_AxisHints  axis        = &hints->axis[dim];
+    AF_Edge       edges       = axis->edges;
+    AF_Edge       edge_limit  = edges + axis->num_edges;
+    AF_Flags      touch_flag;
+
+
+    if ( dim == AF_DIMENSION_HORZ )
+      touch_flag = AF_FLAG_TOUCH_X;
+    else
+      touch_flag  = AF_FLAG_TOUCH_Y;
+
+    if ( edges < edge_limit )
+    {
+      AF_Point  point;
+      AF_Edge   edge;
+
+
+      for ( point = points; point < point_limit; point++ )
+      {
+        FT_Pos  u, ou, fu;  /* point position */
+        FT_Pos  delta;
+
+
+        if ( point->flags & touch_flag )
+          continue;
+
+        /* if this point is candidate to weak interpolation, we       */
+        /* interpolate it after all strong points have been processed */
+
+        if (  ( point->flags & AF_FLAG_WEAK_INTERPOLATION ) &&
+             !( point->flags & AF_FLAG_INFLECTION )         )
+          continue;
+
+        if ( dim == AF_DIMENSION_VERT )
+        {
+          u  = point->fy;
+          ou = point->oy;
+        }
+        else
+        {
+          u  = point->fx;
+          ou = point->ox;
+        }
+
+        fu = u;
+
+        /* is the point before the first edge? */
+        edge  = edges;
+        delta = edge->fpos - u;
+        if ( delta >= 0 )
+        {
+          u = edge->pos - ( edge->opos - ou );
+          goto Store_Point;
+        }
+
+        /* is the point after the last edge? */
+        edge  = edge_limit - 1;
+        delta = u - edge->fpos;
+        if ( delta >= 0 )
+        {
+          u = edge->pos + ( ou - edge->opos );
+          goto Store_Point;
+        }
+
+        {
+          FT_PtrDist  min, max, mid;
+          FT_Pos      fpos;
+
+
+          /* find enclosing edges */
+          min = 0;
+          max = edge_limit - edges;
+
+#if 1
+          /* for a small number of edges, a linear search is better */
+          if ( max <= 8 )
+          {
+            FT_PtrDist  nn;
+
+
+            for ( nn = 0; nn < max; nn++ )
+              if ( edges[nn].fpos >= u )
+                break;
+
+            if ( edges[nn].fpos == u )
+            {
+              u = edges[nn].pos;
+              goto Store_Point;
+            }
+            min = nn;
+          }
+          else
+#endif
+          while ( min < max )
+          {
+            mid  = ( max + min ) >> 1;
+            edge = edges + mid;
+            fpos = edge->fpos;
+
+            if ( u < fpos )
+              max = mid;
+            else if ( u > fpos )
+              min = mid + 1;
+            else
+            {
+              /* we are on the edge */
+              u = edge->pos;
+              goto Store_Point;
+            }
+          }
+
+          /* point is not on an edge */
+          {
+            AF_Edge  before = edges + min - 1;
+            AF_Edge  after  = edges + min + 0;
+
+
+            /* assert( before && after && before != after ) */
+            if ( before->scale == 0 )
+              before->scale = FT_DivFix( after->pos - before->pos,
+                                         after->fpos - before->fpos );
+
+            u = before->pos + FT_MulFix( fu - before->fpos,
+                                         before->scale );
+          }
+        }
+
+      Store_Point:
+        /* save the point position */
+        if ( dim == AF_DIMENSION_HORZ )
+          point->x = u;
+        else
+          point->y = u;
+
+        point->flags |= touch_flag;
+      }
+    }
+  }
+
+
+  /****************************************************************
+   *
+   *                    WEAK POINT INTERPOLATION
+   *
+   ****************************************************************/
+
+
+  /* Shift the original coordinates of all points between `p1' and */
+  /* `p2' to get hinted coordinates, using the same difference as  */
+  /* given by `ref'.                                               */
+
+  static void
+  af_iup_shift( AF_Point  p1,
+                AF_Point  p2,
+                AF_Point  ref )
+  {
+    AF_Point  p;
+    FT_Pos    delta = ref->u - ref->v;
+
+
+    if ( delta == 0 )
+      return;
+
+    for ( p = p1; p < ref; p++ )
+      p->u = p->v + delta;
+
+    for ( p = ref + 1; p <= p2; p++ )
+      p->u = p->v + delta;
+  }
+
+
+  /* Interpolate the original coordinates of all points between `p1' and  */
+  /* `p2' to get hinted coordinates, using `ref1' and `ref2' as the       */
+  /* reference points.  The `u' and `v' members are the current and       */
+  /* original coordinate values, respectively.                            */
+  /*                                                                      */
+  /* Details can be found in the TrueType bytecode specification.         */
+
+  static void
+  af_iup_interp( AF_Point  p1,
+                 AF_Point  p2,
+                 AF_Point  ref1,
+                 AF_Point  ref2 )
+  {
+    AF_Point  p;
+    FT_Pos    u;
+    FT_Pos    v1 = ref1->v;
+    FT_Pos    v2 = ref2->v;
+    FT_Pos    d1 = ref1->u - v1;
+    FT_Pos    d2 = ref2->u - v2;
+
+
+    if ( p1 > p2 )
+      return;
+
+    if ( v1 == v2 )
+    {
+      for ( p = p1; p <= p2; p++ )
+      {
+        u = p->v;
+
+        if ( u <= v1 )
+          u += d1;
+        else
+          u += d2;
+
+        p->u = u;
+      }
+      return;
+    }
+
+    if ( v1 < v2 )
+    {
+      for ( p = p1; p <= p2; p++ )
+      {
+        u = p->v;
+
+        if ( u <= v1 )
+          u += d1;
+        else if ( u >= v2 )
+          u += d2;
+        else
+          u = ref1->u + FT_MulDiv( u - v1, ref2->u - ref1->u, v2 - v1 );
+
+        p->u = u;
+      }
+    }
+    else
+    {
+      for ( p = p1; p <= p2; p++ )
+      {
+        u = p->v;
+
+        if ( u <= v2 )
+          u += d2;
+        else if ( u >= v1 )
+          u += d1;
+        else
+          u = ref1->u + FT_MulDiv( u - v1, ref2->u - ref1->u, v2 - v1 );
+
+        p->u = u;
+      }
+    }
+  }
+
+
+  /* Hint the weak points -- this is equivalent to the TrueType `IUP' */
+  /* hinting instruction.                                             */
+
+  FT_LOCAL_DEF( void )
+  af_glyph_hints_align_weak_points( AF_GlyphHints  hints,
+                                    AF_Dimension   dim )
+  {
+    AF_Point   points        = hints->points;
+    AF_Point   point_limit   = points + hints->num_points;
+    AF_Point*  contour       = hints->contours;
+    AF_Point*  contour_limit = contour + hints->num_contours;
+    AF_Flags   touch_flag;
+    AF_Point   point;
+    AF_Point   end_point;
+    AF_Point   first_point;
+
+
+    /* PASS 1: Move segment points to edge positions */
+
+    if ( dim == AF_DIMENSION_HORZ )
+    {
+      touch_flag = AF_FLAG_TOUCH_X;
+
+      for ( point = points; point < point_limit; point++ )
+      {
+        point->u = point->x;
+        point->v = point->ox;
+      }
+    }
+    else
+    {
+      touch_flag = AF_FLAG_TOUCH_Y;
+
+      for ( point = points; point < point_limit; point++ )
+      {
+        point->u = point->y;
+        point->v = point->oy;
+      }
+    }
+
+    point = points;
+
+    for ( ; contour < contour_limit; contour++ )
+    {
+      AF_Point  first_touched, last_touched;
+
+
+      point       = *contour;
+      end_point   = point->prev;
+      first_point = point;
+
+      /* find first touched point */
+      for (;;)
+      {
+        if ( point > end_point )  /* no touched point in contour */
+          goto NextContour;
+
+        if ( point->flags & touch_flag )
+          break;
+
+        point++;
+      }
+
+      first_touched = point;
+      last_touched  = point;
+
+      for (;;)
+      {
+        FT_ASSERT( point <= end_point                 &&
+                   ( point->flags & touch_flag ) != 0 );
+
+        /* skip any touched neighbours */
+        while ( point < end_point                    &&
+                ( point[1].flags & touch_flag ) != 0 )
+          point++;
+
+        last_touched = point;
+
+        /* find the next touched point, if any */
+        point++;
+        for (;;)
+        {
+          if ( point > end_point )
+            goto EndContour;
+
+          if ( ( point->flags & touch_flag ) != 0 )
+            break;
+
+          point++;
+        }
+
+        /* interpolate between last_touched and point */
+        af_iup_interp( last_touched + 1, point - 1,
+                       last_touched, point );
+      }
+
+    EndContour:
+      /* special case: only one point was touched */
+      if ( last_touched == first_touched )
+        af_iup_shift( first_point, end_point, first_touched );
+
+      else /* interpolate the last part */
+      {
+        if ( last_touched < end_point )
+          af_iup_interp( last_touched + 1, end_point,
+                         last_touched, first_touched );
+
+        if ( first_touched > points )
+          af_iup_interp( first_point, first_touched - 1,
+                         last_touched, first_touched );
+      }
+
+    NextContour:
+      ;
+    }
+
+    /* now save the interpolated values back to x/y */
+    if ( dim == AF_DIMENSION_HORZ )
+    {
+      for ( point = points; point < point_limit; point++ )
+        point->x = point->u;
+    }
+    else
+    {
+      for ( point = points; point < point_limit; point++ )
+        point->y = point->u;
+    }
+  }
+
+
+#ifdef AF_CONFIG_OPTION_USE_WARPER
+
+  /* Apply (small) warp scale and warp delta for given dimension. */
+
+  FT_LOCAL_DEF( void )
+  af_glyph_hints_scale_dim( AF_GlyphHints  hints,
+                            AF_Dimension   dim,
+                            FT_Fixed       scale,
+                            FT_Pos         delta )
+  {
+    AF_Point  points       = hints->points;
+    AF_Point  points_limit = points + hints->num_points;
+    AF_Point  point;
+
+
+    if ( dim == AF_DIMENSION_HORZ )
+    {
+      for ( point = points; point < points_limit; point++ )
+        point->x = FT_MulFix( point->fx, scale ) + delta;
+    }
+    else
+    {
+      for ( point = points; point < points_limit; point++ )
+        point->y = FT_MulFix( point->fy, scale ) + delta;
+    }
+  }
+
+#endif /* AF_CONFIG_OPTION_USE_WARPER */
+
+/* END */