ahhint.c

下载来的一个看图软件的源代码

              {
                /* we are on the edge */
                u = edge->pos;
                goto Store_Point;
              }
            }

            {
              AH_Edge  before = edges + min - 1;
              AH_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 );
            }
          }

#else /* !0 */

          /* otherwise, interpolate the point in between */
          {
            AH_Edge  before = 0;
            AH_Edge  after  = 0;


            for ( edge = edges; edge < edge_limit; edge++ )
            {
              if ( u == edge->fpos )
              {
                u = edge->pos;
                goto Store_Point;
              }
              if ( u < edge->fpos )
                break;
              before = edge;
            }

            for ( edge = edge_limit - 1; edge >= edges; edge-- )
            {
              if ( u == edge->fpos )
              {
                u = edge->pos;
                goto Store_Point;
              }
              if ( u > edge->fpos )
                break;
              after = edge;
            }

            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 );
          }

#endif /* !0 */

        Store_Point:

          /* save the point position */
          if ( dimension )
            point->y = u;
          else
            point->x = u;

          point->flags |= touch_flag;
        }

      edges      = outline->vert_edges;
      edge_limit = edges + outline->num_vedges;
      touch_flag = AH_FLAG_TOUCH_X;
    }
  }


#ifndef AH_OPTION_NO_WEAK_INTERPOLATION

  static void
  ah_iup_shift( AH_Point  p1,
                AH_Point  p2,
                AH_Point  ref )
  {
    AH_Point  p;
    FT_Pos    delta = ref->u - ref->v;


    for ( p = p1; p < ref; p++ )
      p->u = p->v + delta;

    for ( p = ref + 1; p <= p2; p++ )
      p->u = p->v + delta;
  }


  static void
  ah_iup_interp( AH_Point  p1,
                 AH_Point  p2,
                 AH_Point  ref1,
                 AH_Point  ref2 )
  {
    AH_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;
      }
    }
  }


  /* interpolate weak points -- this is equivalent to the TrueType `IUP' */
  /* hinting instruction                                                 */
  static void
  ah_hinter_align_weak_points( AH_Hinter  hinter )
  {
    AH_Outline  outline = hinter->glyph;
    FT_Int      dimension;
    AH_Point    points;
    AH_Point    point_limit;
    AH_Point*   contour_limit;
    AH_Flags    touch_flag;


    points      = outline->points;
    point_limit = points + outline->num_points;

    /* PASS 1: Move segment points to edge positions */

    touch_flag = AH_FLAG_TOUCH_Y;

    contour_limit = outline->contours + outline->num_contours;

    ah_setup_uv( outline, AH_UV_OY );

    for ( dimension = 1; dimension >= 0; dimension-- )
    {
      AH_Point   point;
      AH_Point   end_point;
      AH_Point   first_point;
      AH_Point*  contour;


      point   = points;
      contour = outline->contours;

      for ( ; contour < contour_limit; contour++ )
      {
        point       = *contour;
        end_point   = point->prev;
        first_point = point;

        while ( point <= end_point && !( point->flags & touch_flag ) )
          point++;

        if ( point <= end_point )
        {
          AH_Point  first_touched = point;
          AH_Point  cur_touched   = point;


          point++;
          while ( point <= end_point )
          {
            if ( point->flags & touch_flag )
            {
              /* we found two successive touched points; we interpolate */
              /* all contour points between them                        */
              ah_iup_interp( cur_touched + 1, point - 1,
                             cur_touched, point );
              cur_touched = point;
            }
            point++;
          }

          if ( cur_touched == first_touched )
          {
            /* this is a special case: only one point was touched in the */
            /* contour; we thus simply shift the whole contour           */
            ah_iup_shift( first_point, end_point, cur_touched );
          }
          else
          {
            /* now interpolate after the last touched point to the end */
            /* of the contour                                          */
            ah_iup_interp( cur_touched + 1, end_point,
                           cur_touched, first_touched );

            /* if the first contour point isn't touched, interpolate */
            /* from the contour start to the first touched point     */
            if ( first_touched > points )
              ah_iup_interp( first_point, first_touched - 1,
                             cur_touched, first_touched );
          }
        }
      }

      /* now save the interpolated values back to x/y */
      if ( dimension )
      {
        for ( point = points; point < point_limit; point++ )
          point->y = point->u;

        touch_flag = AH_FLAG_TOUCH_X;
        ah_setup_uv( outline, AH_UV_OX );
      }
      else
      {
        for ( point = points; point < point_limit; point++ )
          point->x = point->u;

        break;  /* exit loop */
      }
    }
  }

#endif /* !AH_OPTION_NO_WEAK_INTERPOLATION */


  FT_LOCAL_DEF( void )
  ah_hinter_align_points( AH_Hinter  hinter )
  {
    ah_hinter_align_edge_points( hinter );

#ifndef AH_OPTION_NO_STRONG_INTERPOLATION
    ah_hinter_align_strong_points( hinter );
#endif

#ifndef AH_OPTION_NO_WEAK_INTERPOLATION
    ah_hinter_align_weak_points( hinter );
#endif
  }


  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /****                                                                 ****/
  /****       H I N T E R   O B J E C T   M E T H O D S                 ****/
  /****                                                                 ****/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/


  /* scale and fit the global metrics */
  static void
  ah_hinter_scale_globals( AH_Hinter  hinter,
                           FT_Fixed   x_scale,
                           FT_Fixed   y_scale )
  {
    FT_Int           n;
    AH_Face_Globals  globals = hinter->globals;
    AH_Globals       design  = &globals->design;
    AH_Globals       scaled  = &globals->scaled;


    /* copy content */
    *scaled = *design;

    /* scale the standard widths & heights */
    for ( n = 0; n < design->num_widths; n++ )
      scaled->widths[n] = FT_MulFix( design->widths[n], x_scale );

    for ( n = 0; n < design->num_heights; n++ )
      scaled->heights[n] = FT_MulFix( design->heights[n], y_scale );

    scaled->stds[0] = ( design->num_widths  > 0 ) ? scaled->widths[0]  : 32000;
    scaled->stds[1] = ( design->num_heights > 0 ) ? scaled->heights[0] : 32000;

    /* scale the blue zones */
    for ( n = 0; n < AH_BLUE_MAX; n++ )
    {
      FT_Pos  delta, delta2;


      delta = design->blue_shoots[n] - design->blue_refs[n];
      delta2 = delta;
      if ( delta < 0 )
        delta2 = -delta2;
      delta2 = FT_MulFix( delta2, y_scale );

      if ( delta2 < 32 )
        delta2 = 0;
      else if ( delta2 < 64 )
        delta2 = 32 + ( ( ( delta2 - 32 ) + 16 ) & -32 );
      else
        delta2 = ( delta2 + 32 ) & -64;

      if ( delta < 0 )
        delta2 = -delta2;

      scaled->blue_refs[n] =
        ( FT_MulFix( design->blue_refs[n], y_scale ) + 32 ) & -64;
      scaled->blue_shoots[n] = scaled->blue_refs[n] + delta2;
    }

    globals->x_scale = x_scale;
    globals->y_scale = y_scale;
  }


  static void
  ah_hinter_align( AH_Hinter  hinter )
  {
    ah_hinter_align_edge_points( hinter );
    ah_hinter_align_points( hinter );
  }


  /* finalize a hinter object */
  FT_LOCAL_DEF( void )
  ah_hinter_done( AH_Hinter  hinter )
  {
    if ( hinter )
    {
      FT_Memory  memory = hinter->memory;


      ah_loader_done( hinter->loader );
      ah_outline_done( hinter->glyph );

      /* note: the `globals' pointer is _not_ owned by the hinter */
      /*       but by the current face object; we don't need to   */
      /*       release it                                         */
      hinter->globals = 0;
      hinter->face    = 0;

      FT_FREE( hinter );
    }
  }


  /* create a new empty hinter object */
  FT_LOCAL_DEF( FT_Error )
  ah_hinter_new( FT_Library  library,
                 AH_Hinter  *ahinter )
  {
    AH_Hinter  hinter = 0;
    FT_Memory  memory = library->memory;
    FT_Error   error;


    *ahinter = 0;

    /* allocate object */
    if ( FT_NEW( hinter ) )
      goto Exit;

    hinter->memory = memory;
    hinter->flags  = 0;

    /* allocate outline and loader */
    error = ah_outline_new( memory, &hinter->glyph )  ||
            ah_loader_new ( memory, &hinter->loader ) ||
            ah_loader_create_extra( hinter->loader );
    if ( error )
      goto Exit;

    *ahinter = hinter;

  Exit:
    if ( error )
      ah_hinter_done( hinter );

    return error;
  }


  /* create a face's autohint globals */
  FT_LOCAL_DEF( FT_Error )
  ah_hinter_new_face_globals( AH_Hinter   hinter,
                              FT_Face     face,
                              AH_Globals  globals )
  {
    FT_Error         error;
    FT_Memory        memory = hinter->memory;
    AH_Face_Globals  face_globals;


    if ( FT_NEW( face_globals ) )
      goto Exit;

    hinter->face    = face;
    hinter->globals = face_globals;

    if ( globals )
      face_globals->design = *globals;
    else
      ah_hinter_compute_globals( hinter );

    face->autohint.data      = face_globals;
    face->autohint.finalizer = (FT_Generic_Finalizer)
                                 ah_hinter_done_face_globals;
    face_globals->face       = face;

  Exit:
    return error;
  }


  /* discard a face's autohint globals */
  FT_LOCAL_DEF( void )
  ah_hinter_done_face_globals( AH_Face_Globals  globals )
  {
    FT_Face    face   = globals->face;
    FT_Memory  memory = face->memory;


    FT_FREE( globals );
  }


  static FT_Error
  ah_hinter_load( AH_Hinter  hinter,
                  FT_UInt    glyph_index,
                  FT_Int32   load_flags,
                  FT_UInt    depth )
  {
    FT_Face           face     = hinter->face;
    FT_GlyphSlot      slot     = face->glyph;