/src/gpac/src/utils/path2d_stroker.c

Source
/***************************************************************************/
/*                                                                         */
/*  ftstroke.c                                                             */
/*                                                                         */
/*    FreeType path stroker (body).                                        */
/*                                                                         */
/*  Copyright 2002, 2003, 2004 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 <gpac/path2d.h>

#ifndef GPAC_DISABLE_EVG

/***************************************************************************/
/***************************************************************************/
/*****                                                                 *****/
/*****                       BEZIER COMPUTATIONS                       *****/
/*****                                                                 *****/
/***************************************************************************/
/***************************************************************************/

#define FT_SMALL_CONIC_THRESHOLD  ( GF_PI / 6 )
#define FT_SMALL_CUBIC_THRESHOLD  ( GF_PI / 6 )

#define FT_IS_SMALL( x )  ( (x) > -FIX_EPSILON && (x) < FIX_EPSILON )

#if 0 //unused

static void ft_conic_split(GF_Point2D*  base )
{
  Fixed  a, b;

  base[4].x = base[2].x;
  b = base[1].x;
  a = base[3].x = ( base[2].x + b ) / 2;
  b = base[1].x = ( base[0].x + b ) / 2;
  base[2].x = ( a + b ) / 2;

  base[4].y = base[2].y;
  b = base[1].y;
  a = base[3].y = ( base[2].y + b ) / 2;
  b = base[1].y = ( base[0].y + b ) / 2;
  base[2].y = ( a + b ) / 2;
}



static Bool ft_conic_is_small_enough( GF_Point2D*  base, Fixed *angle_in, Fixed *angle_out)
{
  GF_Point2D  d1, d2;
  Fixed theta;
  s32 close1, close2;
  d1.x = base[1].x - base[2].x;
  d1.y = base[1].y - base[2].y;
  d2.x = base[0].x - base[1].x;
  d2.y = base[0].y - base[1].y;
  close1 = FT_IS_SMALL( d1.x ) && FT_IS_SMALL( d1.y );
  close2 = FT_IS_SMALL( d2.x ) && FT_IS_SMALL( d2.y );

  if ( close1 ) {
    if ( close2 )
      *angle_in = *angle_out = 0;
    else
      *angle_in = *angle_out = gf_atan2(d2.y, d2.x);
  }
  else if ( close2 ) {
    *angle_in = *angle_out = gf_atan2(d1.y, d1.x);
  } else {
    *angle_in  = gf_atan2(d1.y, d1.x);
    *angle_out = gf_atan2(d2.y, d2.x);
  }
  theta = ABS( gf_angle_diff(*angle_in, *angle_out));
  return ( theta < FT_SMALL_CONIC_THRESHOLD ) ? GF_TRUE : GF_FALSE;
}

static void ft_cubic_split( GF_Point2D*  base )
{
  Fixed  a, b, c, d;
  base[6].x = base[3].x;
  c = base[1].x;
  d = base[2].x;
  base[1].x = a = ( base[0].x + c ) / 2;
  base[5].x = b = ( base[3].x + d ) / 2;
  c = ( c + d ) / 2;
  base[2].x = a = ( a + c ) / 2;
  base[4].x = b = ( b + c ) / 2;
  base[3].x = ( a + b ) / 2;

  base[6].y = base[3].y;
  c = base[1].y;
  d = base[2].y;
  base[1].y = a = ( base[0].y + c ) / 2;
  base[5].y = b = ( base[3].y + d ) / 2;
  c = ( c + d ) / 2;
  base[2].y = a = ( a + c ) / 2;
  base[4].y = b = ( b + c ) / 2;
  base[3].y = ( a + b ) / 2;
}


static Bool ft_cubic_is_small_enough(GF_Point2D *base, Fixed *angle_in, Fixed *angle_mid, Fixed *angle_out)
{
  GF_Point2D  d1, d2, d3;
  Fixed theta1, theta2;
  s32 close1, close2, close3;
  d1.x = base[2].x - base[3].x;
  d1.y = base[2].y - base[3].y;
  d2.x = base[1].x - base[2].x;
  d2.y = base[1].y - base[2].y;
  d3.x = base[0].x - base[1].x;
  d3.y = base[0].y - base[1].y;

  close1 = FT_IS_SMALL( d1.x ) && FT_IS_SMALL( d1.y );
  close2 = FT_IS_SMALL( d2.x ) && FT_IS_SMALL( d2.y );
  close3 = FT_IS_SMALL( d3.x ) && FT_IS_SMALL( d3.y );

  if ( close1 || close3 ) {
    if ( close2 ) {
      /* basically a point */
      *angle_in = *angle_out = *angle_mid = 0;
    } else if ( close1 ) {
      *angle_in  = *angle_mid = gf_atan2( d2.y, d2.x);
      *angle_out = gf_atan2( d3.y, d3.x);
    }
    /* close2 */
    else {
      *angle_in  = gf_atan2(d1.y, d1.x);
      *angle_mid = *angle_out = gf_atan2(d2.y, d2.x);
    }
  }
  else if ( close2 ) {
    *angle_in  = *angle_mid = gf_atan2(d1.y, d1.x);
    *angle_out = gf_atan2(d3.y, d3.x);
  } else {
    *angle_in  = gf_atan2(d1.y, d1.x);
    *angle_mid = gf_atan2(d2.y, d2.x);
    *angle_out = gf_atan2(d3.y, d3.x);
  }
  theta1 = ABS( gf_angle_diff( *angle_in,  *angle_mid ) );
  theta2 = ABS( gf_angle_diff( *angle_mid, *angle_out ) );
  return ((theta1 < FT_SMALL_CUBIC_THRESHOLD) && (theta2 < FT_SMALL_CUBIC_THRESHOLD )) ? GF_TRUE : GF_FALSE;
}

#endif

/***************************************************************************/
/***************************************************************************/
/*****                                                                 *****/
/*****                       STROKE BORDERS                            *****/
/*****                                                                 *****/
/***************************************************************************/
/***************************************************************************/

typedef enum
{
  FT_STROKE_TAG_ON    = 1,   /* on-curve point  */
  FT_STROKE_TAG_CUBIC = 2,   /* cubic off-point */
  FT_STROKE_TAG_BEGIN = 4,   /* sub-path start  */
  FT_STROKE_TAG_END   = 8    /* sub-path end    */
} FT_StrokeTags;


typedef struct  FT_StrokeBorderRec_
{
  u32 num_points;
  u32 max_points;
  GF_Point2D*  points;
  u8 *tags;
  Bool movable;
  /* index of current sub-path start point */
  s32 start;
  Bool valid;
} FT_StrokeBorderRec, *FT_StrokeBorder;


static s32 ft_stroke_border_grow(FT_StrokeBorder  border, u32 new_points)
{
  u32 new_max = border->num_points + new_points;
  if (new_max > border->max_points) {
    u32 cur_max = new_max*2;
    border->points = (GF_Point2D *) gf_realloc(border->points, sizeof(GF_Point2D)*cur_max);
    border->tags = (u8 *) gf_realloc(border->tags, sizeof(u8)*cur_max);
    if (!border->points || !border->tags) return -1;
    border->max_points = cur_max;
  }
  return 0;
}

static void ft_stroke_border_close( FT_StrokeBorder  border )
{
  /* don't record empty paths! */
  if ((border->start <0) || !border->num_points ) return;
  if ( border->num_points > (u32)border->start ) {
    border->tags[border->start] |= FT_STROKE_TAG_BEGIN;
    border->tags[border->num_points - 1] |= FT_STROKE_TAG_END;
  }
  border->start   = -1;
  border->movable = GF_FALSE;
}

static s32 ft_stroke_border_lineto( FT_StrokeBorder  border, GF_Point2D*       to, Bool movable )
{
  gf_assert(border->start >= 0);

  if ( border->movable ) {
    /* move last point */
    border->points[border->num_points - 1] = *to;
  } else {
    /* add one point */
    if (ft_stroke_border_grow( border, 1 )==0) {
      GF_Point2D*  vec = border->points + border->num_points;
      u8 *tag = border->tags   + border->num_points;

      vec[0] = *to;
      tag[0] = FT_STROKE_TAG_ON;
      border->num_points += 1;
    } else {
      return -1;
    }
  }
  border->movable = movable;
  return 0;
}

#if 0 //unused
static s32 ft_stroke_border_conicto( FT_StrokeBorder  border, GF_Point2D*       control, GF_Point2D*       to )
{
  gf_assert( border->start >= 0 );
  if (ft_stroke_border_grow( border, 2 )==0) {
    GF_Point2D*  vec = border->points + border->num_points;
    u8 *tag = border->tags   + border->num_points;

    vec[0] = *control;
    vec[1] = *to;

    tag[0] = 0;
    tag[1] = FT_STROKE_TAG_ON;

    border->num_points += 2;
  } else {
    return -1;
  }
  border->movable = GF_FALSE;
  return 0;
}
#endif

static s32 ft_stroke_border_cubicto( FT_StrokeBorder  border,
                                     GF_Point2D*       control1,
                                     GF_Point2D*       control2,
                                     GF_Point2D*       to )
{
  gf_assert( border->start >= 0 );

  if (!ft_stroke_border_grow( border, 3 )) {
    GF_Point2D*  vec = border->points + border->num_points;
    u8*    tag = border->tags   + border->num_points;
    vec[0] = *control1;
    vec[1] = *control2;
    vec[2] = *to;

    tag[0] = FT_STROKE_TAG_CUBIC;
    tag[1] = FT_STROKE_TAG_CUBIC;
    tag[2] = FT_STROKE_TAG_ON;

    border->num_points += 3;
  } else {
    return -1;
  }
  border->movable = GF_FALSE;
  return 0;
}

#define FT_ARC_CUBIC_ANGLE  ( GF_PI / 2 )


static s32 ft_stroke_border_arcto( FT_StrokeBorder  border,
                                   GF_Point2D*       center,
                                   Fixed         radius,
                                   Fixed angle_start,
                                   Fixed angle_diff )
{
  Fixed total, angle, step, rotate, next, theta;
  GF_Point2D  a, b, a2, b2;
  Fixed length;
  /* compute start point */
  a = gf_v2d_from_polar(radius, angle_start );
  a.x += center->x;
  a.y += center->y;

  total  = angle_diff;
  angle  = angle_start;
  rotate = ( angle_diff >= 0 ) ? GF_PI2 : -GF_PI2;

  while ( total != 0 ) {
    step = total;
    if ( step > FT_ARC_CUBIC_ANGLE )
      step = FT_ARC_CUBIC_ANGLE;
    else if ( step < -FT_ARC_CUBIC_ANGLE )
      step = -FT_ARC_CUBIC_ANGLE;

    next  = angle + step;
    theta = step;
    if ( theta < 0 )
      theta = -theta;

#ifdef GPAC_FIXED_POINT
    theta >>= 1;
#else
    theta /= 2;
#endif

    /* compute end point */
    b = gf_v2d_from_polar(radius, next );
    b.x += center->x;
    b.y += center->y;

    /* compute first and second control points */
    length = gf_muldiv( radius, gf_sin( theta ) * 4, ( FIX_ONE + gf_cos( theta ) ) * 3 );

    a2 = gf_v2d_from_polar(length, angle + rotate );
    a2.x += a.x;
    a2.y += a.y;

    b2 = gf_v2d_from_polar(length, next - rotate );
    b2.x += b.x;
    b2.y += b.y;

    /* add cubic arc */
    if (ft_stroke_border_cubicto( border, &a2, &b2, &b ) != 0) return -1;

    /* process the rest of the arc ?? */
    a      = b;
    total -= step;
    angle  = next;
  }
  return 0;
}


static s32 ft_stroke_border_moveto(FT_StrokeBorder  border, GF_Point2D*       to )
{
  /* close current open path if any ? */
  if ( border->start >= 0 )
    ft_stroke_border_close( border );

  border->start   = border->num_points;
  border->movable = GF_FALSE;
  return ft_stroke_border_lineto(border, to, GF_FALSE);
}


static s32 ft_stroke_border_get_counts(FT_StrokeBorder  border,
                                       u32 *anum_points,
                                       u32 *anum_contours )
{
  s32 error        = 0;
  u32 num_points   = 0;
  u32 num_contours = 0;
  u32 count      = border->num_points;
  GF_Point2D *point      = border->points;
  u8 *tags       = border->tags;
  s32 in_contour = 0;

  for ( ; count > 0; count--, num_points++, point++, tags++ ) {
    if ( tags[0] & FT_STROKE_TAG_BEGIN ) {
      if ( in_contour != 0 ) goto Fail;

      in_contour = 1;
    } else if ( in_contour == 0 )
      goto Fail;

    if ( tags[0] & FT_STROKE_TAG_END ) {
      if ( in_contour == 0 )
        goto Fail;
      in_contour = 0;
      num_contours++;
    }
  }

  if ( in_contour != 0 )
    goto Fail;

  border->valid = GF_TRUE;

Exit:
  *anum_points   = num_points;
  *anum_contours = num_contours;
  return error;

Fail:
  num_points   = 0;
  num_contours = 0;
  error = -1;
  goto Exit;
}


static void ft_stroke_border_export( FT_StrokeBorder  border, GF_Path*      outline )
{
  if (!border->num_points) return;

  /* copy point locations */
  memcpy(outline->points + outline->n_points, border->points, sizeof(GF_Point2D)*border->num_points);

  /* copy tags */
  {
    u32 count = border->num_points;
    u8*  read  = border->tags;
    u8*  write = (u8*)outline->tags + outline->n_points;

    for ( ; count > 0; count--, read++, write++ ) {
      if ( *read & FT_STROKE_TAG_ON )
        *write = GF_PATH_CURVE_ON;
      else if ( *read & FT_STROKE_TAG_CUBIC )
        *write = GF_PATH_CURVE_CUBIC;
      else
        *write = GF_PATH_CURVE_CONIC;
    }
  }

  /* copy contours */
  {
    u32 count = border->num_points;
    u8 *tags  = border->tags;
    u32 *write = outline->contours + outline->n_contours;
    u32 idx = outline->n_points;

    for ( ; count > 0; count--, tags++, idx++ ) {
      if ( *tags & FT_STROKE_TAG_END ) {
        *write++ = idx;
        outline->n_contours++;
      }
    }
  }
  outline->n_points = outline->n_points + border->num_points;
}


/***************************************************************************/
/***************************************************************************/
/*****                                                                 *****/
/*****                           STROKER                               *****/
/*****                                                                 *****/
/***************************************************************************/
/***************************************************************************/

#define FT_SIDE_TO_ROTATE( s )   ( GF_PI2 - (s) * GF_PI )

typedef struct  FT_StrokerRec_
{
  Fixed angle_in;
  Fixed angle_out;
  GF_Point2D            center;
  Bool              first_point;
  Fixed subpath_angle;
  GF_Point2D            subpath_start;

  u32 line_cap;
  u32 line_join;
  Fixed miter_limit;
  Fixed radius;
  Bool              valid;
  Bool              closing;
  FT_StrokeBorderRec   borders[2];
} FT_StrokerRec, FT_Stroker;


/* creates a circular arc at a corner or cap */
static s32 ft_stroker_arcto( FT_Stroker  *stroker, s32 side )
{
  Fixed total, rotate;
  Fixed         radius = stroker->radius;
  s32 error  = 0;
  FT_StrokeBorder  border = stroker->borders + side;
  rotate = FT_SIDE_TO_ROTATE( side );
  total = gf_angle_diff( stroker->angle_in, stroker->angle_out);
  if ( total == GF_PI ) total = -rotate * 2;
  error = ft_stroke_border_arcto( border,
                                  &stroker->center,
                                  radius,
                                  stroker->angle_in + rotate,
                                  total );
  border->movable = GF_FALSE;
  return error;
}

/* adds a cap at the end of an opened path */
static s32 ft_stroker_cap(FT_Stroker  *stroker, Fixed angle, s32 side)
{
  s32 error  = 0;
  if ( stroker->line_cap == GF_LINE_CAP_ROUND) {
    /* OK we cheat a bit here compared to FT original code, and use a rough cubic cap instead of
    a circle to deal with arbitrary orientation of regular paths where arc cap is not always properly oriented.
    Rather than computing orientation we simply approximate to conic - btw this takes less memory than
    exact circle cap since cubics are natively supported - we don't use conic since result is not so good looking*/
    GF_Point2D delta, delta2, ctl1, ctl2, end;
    Fixed rotate = FT_SIDE_TO_ROTATE( side );
    Fixed radius = stroker->radius;
    FT_StrokeBorder  border = stroker->borders + side;


    delta = gf_v2d_from_polar(radius, angle);
    delta.x = 4*delta.x/3;
    delta.y = 4*delta.y/3;

    delta2 = gf_v2d_from_polar(radius, angle + rotate);
    ctl1.x = delta.x + stroker->center.x + delta2.x;
    ctl1.y = delta.y + stroker->center.y + delta2.y;

    delta2 = gf_v2d_from_polar(radius, angle - rotate);
    ctl2.x = delta.x + delta2.x + stroker->center.x;
    ctl2.y = delta.y + delta2.y + stroker->center.y;

    end.x = delta2.x + stroker->center.x;
    end.y = delta2.y + stroker->center.y;

    error = ft_stroke_border_cubicto( border, &ctl1, &ctl2, &end);
  } else if ( stroker->line_cap == GF_LINE_CAP_SQUARE) {
    /* add a square cap */
    GF_Point2D        delta, delta2;
    Fixed rotate = FT_SIDE_TO_ROTATE( side );
    Fixed radius = stroker->radius;
    FT_StrokeBorder  border = stroker->borders + side;


    delta2 = gf_v2d_from_polar(radius, angle + rotate);
    delta = gf_v2d_from_polar(radius, angle);

    delta.x += stroker->center.x + delta2.x;
    delta.y += stroker->center.y + delta2.y;

    error = ft_stroke_border_lineto(border, &delta, GF_FALSE);
    if ( error )
      goto Exit;

    delta2 = gf_v2d_from_polar(radius, angle - rotate);
    delta = gf_v2d_from_polar(radius, angle);

    delta.x += delta2.x + stroker->center.x;
    delta.y += delta2.y + stroker->center.y;

    error = ft_stroke_border_lineto(border, &delta, GF_FALSE);
  } else if ( stroker->line_cap == GF_LINE_CAP_TRIANGLE) {
    /* add a triangle cap */
    GF_Point2D delta;
    Fixed radius = stroker->radius;
    FT_StrokeBorder  border = stroker->borders + side;
    border->movable = GF_FALSE;
    delta = gf_v2d_from_polar(radius, angle);
    delta.x += stroker->center.x;
    delta.y += stroker->center.y;
    error = ft_stroke_border_lineto(border, &delta, GF_FALSE);
  }

Exit:
  return error;
}


/* process an inside corner, i.e. compute intersection */
static s32 ft_stroker_inside(FT_Stroker *stroker, s32 side)
{
  FT_StrokeBorder  border = stroker->borders + side;
  Fixed phi, theta, rotate;
  Fixed length, thcos, sigma;
  GF_Point2D        delta;
  s32 error = 0;

  rotate = FT_SIDE_TO_ROTATE( side );

  /* compute median angle */
  theta = gf_angle_diff( stroker->angle_in, stroker->angle_out );
  if ( theta == GF_PI )
    theta = rotate;
  else
    theta = theta / 2;

  phi = stroker->angle_in + theta;

  thcos  = gf_cos( theta );
  sigma  = gf_mulfix( stroker->miter_limit, thcos );

  if ( sigma < FIX_ONE ) {
    delta = gf_v2d_from_polar(stroker->radius, stroker->angle_out + rotate );
    delta.x += stroker->center.x;
    delta.y += stroker->center.y;
    if (!stroker->closing) border->movable = GF_FALSE;
  } else {
    length = gf_divfix( stroker->radius, thcos );
    delta = gf_v2d_from_polar(length, phi + rotate );
    delta.x += stroker->center.x;
    delta.y += stroker->center.y;
  }
  error = ft_stroke_border_lineto(border, &delta, GF_FALSE);
  return error;
}


/* process an outside corner, i.e. compute bevel/miter/round */
static s32 ft_stroker_outside( FT_Stroker *stroker, s32 side )
{
  FT_StrokeBorder  border = stroker->borders + side;
  s32 error;
  Fixed rotate;
  u32 join = stroker->line_join;

  if ( join == GF_LINE_JOIN_MITER_SVG ) {
    Fixed sin_theta, inv_sin_theta;
    join = GF_LINE_JOIN_MITER;
    sin_theta = gf_sin(gf_angle_diff( stroker->angle_out - GF_PI, stroker->angle_in) / 2 );
    if (sin_theta) {
      inv_sin_theta = gf_invfix(sin_theta);
      if (inv_sin_theta > stroker->miter_limit) join = GF_LINE_JOIN_BEVEL;
    } else {
      join = GF_LINE_JOIN_BEVEL;
    }
  }

  if ( join == GF_LINE_JOIN_ROUND ) {
    error = ft_stroker_arcto( stroker, side );
  } else if (join == GF_LINE_JOIN_BEVEL) {
    GF_Point2D  delta;
    rotate = FT_SIDE_TO_ROTATE( side );
    delta = gf_v2d_from_polar(stroker->radius, stroker->angle_out + rotate );
    delta.x += stroker->center.x;
    delta.y += stroker->center.y;
    /*prevent moving current point*/
    border->movable = GF_FALSE;
    /*and add un-movable end point*/
    error = ft_stroke_border_lineto( border, &delta, GF_FALSE);
  } else {
    /* this is a mitered or beveled corner */
    Fixed  sigma, radius = stroker->radius;
    Fixed theta, phi;
    Fixed thcos;
    Bool  miter = GF_TRUE;

    rotate = FT_SIDE_TO_ROTATE( side );

    theta  = gf_angle_diff( stroker->angle_in, stroker->angle_out );
    if ( theta == GF_PI ) {
      theta = rotate;
      phi   = stroker->angle_in;
    } else {
      theta = theta / 2;
      phi   = stroker->angle_in + theta + rotate;
    }

    thcos = gf_cos( theta );
    sigma = gf_mulfix( stroker->miter_limit, thcos );

    if ( sigma >= FIX_ONE ) {
      miter = GF_FALSE;
    }

    /* this is a miter (broken angle) */
    if ( miter ) {
      GF_Point2D  middle, delta;
      Fixed   length;

      /* compute middle point */
      middle = gf_v2d_from_polar(gf_mulfix(radius, stroker->miter_limit), phi);
      middle.x += stroker->center.x;
      middle.y += stroker->center.y;

      /* compute first angle point */
      length = gf_mulfix(radius, gf_divfix( FIX_ONE - sigma, ABS( gf_sin( theta ) ) ) );

      delta = gf_v2d_from_polar(length, phi + rotate );
      delta.x += middle.x;
      delta.y += middle.y;

      error = ft_stroke_border_lineto( border, &delta, GF_FALSE );
      if ( error )
        goto Exit;

      /* compute second angle point */
      delta = gf_v2d_from_polar(length, phi - rotate);
      delta.x += middle.x;
      delta.y += middle.y;

      error = ft_stroke_border_lineto( border, &delta, GF_FALSE );
      if ( error )
        goto Exit;

      /* finally, add a movable end point */
      delta = gf_v2d_from_polar(radius, stroker->angle_out + rotate );
      delta.x += stroker->center.x;
      delta.y += stroker->center.y;

      error = ft_stroke_border_lineto( border, &delta, GF_TRUE);
    }
    /* this is a bevel (intersection) */
    else {
      Fixed   length;
      GF_Point2D  delta;


      length = gf_divfix( stroker->radius, thcos );

      delta = gf_v2d_from_polar(length, phi );
      delta.x += stroker->center.x;
      delta.y += stroker->center.y;

      error = ft_stroke_border_lineto( border, &delta, GF_FALSE );
      if (error) goto Exit;

      /* now add end point */
      delta = gf_v2d_from_polar(stroker->radius, stroker->angle_out + rotate );
      delta.x += stroker->center.x;
      delta.y += stroker->center.y;

      error = ft_stroke_border_lineto( border, &delta, GF_TRUE );
    }
  }
Exit:
  return error;
}



static s32 ft_stroker_process_corner(FT_Stroker *stroker )
{
  s32 error = 0;
  Fixed turn;
  s32 inside_side;
  turn = gf_angle_diff( stroker->angle_in, stroker->angle_out );

  /* no specific corner processing is required if the turn is 0 */
  if ( turn == 0 )
    goto Exit;

  /* when we turn to the right, the inside side is 0 */
  inside_side = 0;
  /* otherwise, the inside side is 1 */
  if (turn < 0 )
    inside_side = 1;

  /* process the inside side */
  error = ft_stroker_inside( stroker, inside_side );
  if ( error ) goto Exit;

  /* process the outside side */
  error = ft_stroker_outside( stroker, 1 - inside_side );

Exit:
  return error;
}


/* add two points to the left and right borders corresponding to the */
/* start of the subpath..                                            */
static s32 ft_stroker_subpath_start( FT_Stroker *stroker, Fixed start_angle )
{
  GF_Point2D        delta;
  GF_Point2D        point;
  s32 error;
  FT_StrokeBorder  border;

  delta = gf_v2d_from_polar(stroker->radius, start_angle + GF_PI2 );

  point.x = stroker->center.x + delta.x;
  point.y = stroker->center.y + delta.y;

  border = stroker->borders;
  error = ft_stroke_border_moveto( border, &point );
  if ( error )
    goto Exit;

  point.x = stroker->center.x - delta.x;
  point.y = stroker->center.y - delta.y;

  border++;
  error = ft_stroke_border_moveto( border, &point );

  /* save angle for last cap */
  stroker->subpath_angle = start_angle;
  stroker->first_point   = GF_FALSE;

Exit:
  return error;
}


static s32 FT_Stroker_LineTo( FT_Stroker *stroker, GF_Point2D*  to, Bool is_last)
{
  s32 error = 0;
  FT_StrokeBorder  border;
  GF_Point2D        delta;
  Fixed angle;
  s32 side;

  delta.x = to->x - stroker->center.x;
  delta.y = to->y - stroker->center.y;
  if (!is_last && !delta.x && !delta.y) return 0;

  angle = gf_atan2( delta.y, delta.x);
  delta = gf_v2d_from_polar(stroker->radius, angle + GF_PI2 );

  /* process corner if necessary */
  if ( stroker->first_point ) {
    /* This is the first segment of a subpath.  We need to     */
    /* add a point to each border at their respective starting */
    /* point locations.                                        */
    error = ft_stroker_subpath_start( stroker, angle );
    if ( error )
      goto Exit;
  } else {
    /* process the current corner */
    stroker->angle_out = angle;
    error = ft_stroker_process_corner( stroker );
    if ( error )
      goto Exit;
  }

  /* now add a line segment to both the "inside" and "outside" paths */
  for ( border = stroker->borders, side = 1; side >= 0; side--, border++ ) {
    GF_Point2D  point;
    point.x = to->x + delta.x;
    point.y = to->y + delta.y;

    error = ft_stroke_border_lineto( border, &point, GF_TRUE );
    if ( error )
      goto Exit;

    delta.x = -delta.x;
    delta.y = -delta.y;
  }
  stroker->angle_in = angle;
  stroker->center   = *to;

Exit:
  return error;
}

#if 0 //unused
static s32 FT_Stroker_ConicTo(FT_Stroker *stroker, GF_Point2D*  control, GF_Point2D * to)
{
  s32 error = 0;
  GF_Point2D   bez_stack[34];
  GF_Point2D*  arc;
  GF_Point2D*  limit = bez_stack + 30;
  Fixed start_angle;
  Bool first_arc = GF_TRUE;


  arc    = bez_stack;
  arc[0] = *to;
  arc[1] = *control;
  arc[2] = stroker->center;

  while ( arc >= bez_stack ) {
    Fixed angle_in, angle_out;
    angle_in = angle_out = 0;  /* remove compiler warnings */

    if ( arc < limit                                             &&
            !ft_conic_is_small_enough( arc, &angle_in, &angle_out ) )
    {
      ft_conic_split( arc );
      arc += 2;
      continue;
    }

    if ( first_arc ) {
      first_arc = GF_FALSE;

      start_angle = angle_in;

      /* process corner if necessary */
      if ( stroker->first_point )
        error = ft_stroker_subpath_start( stroker, start_angle );
      else {
        stroker->angle_out = start_angle;
        error = ft_stroker_process_corner( stroker );
      }
    }

    /* the arc's angle is small enough; we can add it directly to each */
    /* border                                                          */
    {
      GF_Point2D  ctrl, end;
      Fixed theta, phi, rotate;
      Fixed length;
      s32 side;

      theta  = gf_angle_diff( angle_in, angle_out ) / 2;
      phi    = angle_in + theta;
      length = gf_divfix( stroker->radius, gf_cos( theta ) );

      for ( side = 0; side <= 1; side++ ) {
        rotate = FT_SIDE_TO_ROTATE( side );

        /* compute control point */
        ctrl = gf_v2d_from_polar(length, phi + rotate );
        ctrl.x += arc[1].x;
        ctrl.y += arc[1].y;

        /* compute end point */
        end = gf_v2d_from_polar(stroker->radius, angle_out + rotate );
        end.x += arc[0].x;
        end.y += arc[0].y;

        error = ft_stroke_border_conicto( stroker->borders + side, &ctrl, &end );
        if ( error )
          goto Exit;
      }
    }

    arc -= 2;

    if ( arc < bez_stack )
      stroker->angle_in = angle_out;
  }

  stroker->center = *to;
Exit:
  return error;
}


static s32 FT_Stroker_CubicTo(FT_Stroker *stroker,
                              GF_Point2D*  control1,
                              GF_Point2D*  control2,
                              GF_Point2D*  to )
{
  s32 error = 0;
  GF_Point2D   bez_stack[37];
  GF_Point2D*  arc;
  GF_Point2D*  limit = bez_stack + 32;
  Fixed start_angle;
  Bool     first_arc = GF_TRUE;

  arc    = bez_stack;
  arc[0] = *to;
  arc[1] = *control2;
  arc[2] = *control1;
  arc[3] = stroker->center;

  while ( arc >= bez_stack ) {
    Fixed angle_in, angle_mid, angle_out;
    /* remove compiler warnings */
    angle_in = angle_out = angle_mid = 0;

    if (arc < limit &&
            !ft_cubic_is_small_enough( arc, &angle_in, &angle_mid, &angle_out ) )
    {
      ft_cubic_split( arc );
      arc += 3;
      continue;
    }

    if ( first_arc ) {
      first_arc = GF_FALSE;

      /* process corner if necessary */
      start_angle = angle_in;

      if ( stroker->first_point )
        error = ft_stroker_subpath_start( stroker, start_angle );
      else {
        stroker->angle_out = start_angle;
        error = ft_stroker_process_corner( stroker );
      }
      if ( error )
        goto Exit;
    }

    /* the arc's angle is small enough; we can add it directly to each */
    /* border                                                          */
    {
      GF_Point2D  ctrl1, ctrl2, end;
      Fixed theta1, phi1, theta2, phi2, rotate;
      Fixed length1, length2;
      s32 side;


      theta1  = ABS( angle_mid - angle_in ) / 2;
      theta2  = ABS( angle_out - angle_mid ) / 2;
      phi1    = (angle_mid + angle_in ) / 2;
      phi2    = (angle_mid + angle_out ) / 2;
      length1 = gf_divfix( stroker->radius, gf_cos( theta1 ) );
      length2 = gf_divfix( stroker->radius, gf_cos(theta2) );

      for ( side = 0; side <= 1; side++ ) {
        rotate = FT_SIDE_TO_ROTATE( side );

        /* compute control points */
        ctrl1 = gf_v2d_from_polar(length1, phi1 + rotate );
        ctrl1.x += arc[2].x;
        ctrl1.y += arc[2].y;

        ctrl2 = gf_v2d_from_polar(length2, phi2 + rotate );
        ctrl2.x += arc[1].x;
        ctrl2.y += arc[1].y;

        /* compute end point */
        end = gf_v2d_from_polar(stroker->radius, angle_out + rotate );
        end.x += arc[0].x;
        end.y += arc[0].y;

        error = ft_stroke_border_cubicto( stroker->borders + side,
                                          &ctrl1, &ctrl2, &end );
        if ( error )
          goto Exit;
      }
    }

    arc -= 3;
    if ( arc < bez_stack )
      stroker->angle_in = angle_out;
  }

  stroker->center = *to;

Exit:
  return error;
}
#endif



static s32 FT_Stroker_BeginSubPath(FT_Stroker *stroker, GF_Point2D*  to)
{
  /* We cannot process the first point, because there is not enough      */
  /* information regarding its corner/cap.  The latter will be processed */
  /* in the "end_subpath" routine.                                       */
  /*                                                                     */
  stroker->first_point   = GF_TRUE;
  stroker->center        = *to;

  /* record the subpath start point index for each border */
  stroker->subpath_start = *to;
  return 0;
}

static s32 ft_stroker_add_reverse_left( FT_Stroker *stroker, Bool     open )
{
  FT_StrokeBorder  right  = stroker->borders + 0;
  FT_StrokeBorder  left   = stroker->borders + 1;
  s32 new_points;
  s32 error  = 0;

  if (!left->num_points) return 0;

  gf_assert( left->start >= 0 );
  new_points = left->num_points - left->start;
  if ( new_points > 0 ) {
    error = ft_stroke_border_grow( right, (u32)new_points );
    if ( error )
      goto Exit;

    {
      GF_Point2D*  dst_point = right->points + right->num_points;
      u8*    dst_tag   = right->tags   + right->num_points;
      GF_Point2D*  src_point = left->points  + left->num_points - 1;
      u8*    src_tag   = left->tags    + left->num_points - 1;

      while ( src_point >= left->points + left->start ) {
        *dst_point = *src_point;
        *dst_tag   = *src_tag;

        if ( open )
          dst_tag[0] &= ~( FT_STROKE_TAG_BEGIN | FT_STROKE_TAG_END );
        else {
          /* switch begin/end tags if necessary.. */
          if ( dst_tag[0] & ( FT_STROKE_TAG_BEGIN | FT_STROKE_TAG_END ) )
            dst_tag[0] ^= ( FT_STROKE_TAG_BEGIN | FT_STROKE_TAG_END );
        }

        src_point--;
        src_tag--;
        dst_point++;
        dst_tag++;
      }
    }

    left->num_points   = left->start;
    right->num_points += new_points;

    right->movable = GF_FALSE;
    left->movable  = GF_FALSE;
  }

Exit:
  return error;
}

/* there's a lot of magic in this function! */
static s32 FT_Stroker_EndSubPath( FT_Stroker *stroker, Bool do_close)
{
  s32  error  = 0;
  FT_StrokeBorder  right = stroker->borders;
  if (do_close) {
    Fixed turn;
    s32 inside_side;

    /* process the corner */
    stroker->angle_out = stroker->subpath_angle;
    turn               = gf_angle_diff(stroker->angle_in, stroker->angle_out );

    /* no specific corner processing is required if the turn is 0 */
    if ( turn != 0 ) {
      /* when we turn to the right, the inside side is 0 */
      inside_side = 0;

      /* otherwise, the inside side is 1 */
      if ( turn < 0 ) inside_side = 1;

      /* IMPORTANT: WE DO NOT PROCESS THE INSIDE BORDER HERE! */
      /* process the inside side                              */
      /* error = ft_stroker_inside( stroker, inside_side );   */
      /* if ( error )                                         */
      /*   goto Exit;                                         */

      /* process the outside side */
      error = ft_stroker_outside( stroker, 1 - inside_side );
      if ( error )
        goto Exit;
    }

    ft_stroker_add_reverse_left(stroker, GF_FALSE);
    /* then end our two subpaths */
    ft_stroke_border_close( stroker->borders + 0 );
    ft_stroke_border_close( stroker->borders + 1 );
  } else {
    /* All right, this is an opened path, we need to add a cap between */
    /* right & left, add the reverse of left, then add a final cap     */
    /* between left & right.                                           */
    error = ft_stroker_cap( stroker, stroker->angle_in, 0 );
    if ( error ) goto Exit;

    /* add reversed points from "left" to "right" */
    error = ft_stroker_add_reverse_left( stroker, GF_TRUE );
    if ( error ) goto Exit;

    /* now add the final cap */
    stroker->center = stroker->subpath_start;
    error = ft_stroker_cap( stroker,
                            stroker->subpath_angle + GF_PI, 0 );
    if ( error )
      goto Exit;

    /* Now end the right subpath accordingly.  The left one is */
    /* rewind and doesn't need further processing.             */
    ft_stroke_border_close( right );
  }

Exit:
  return error;
}


static s32 FT_Stroker_GetCounts( FT_Stroker *stroker, u32 *anum_points, u32 *anum_contours )
{
  u32 count1, count2, num_points   = 0;
  u32 count3, count4, num_contours = 0;
  s32 error;

  error = ft_stroke_border_get_counts( stroker->borders + 0, &count1, &count2 );
  if ( error ) goto Exit;
  error = ft_stroke_border_get_counts( stroker->borders + 1, &count3, &count4 );
  if ( error ) goto Exit;
  num_points   = count1 + count3;
  num_contours = count2 + count4;

Exit:
  *anum_points   = num_points;
  *anum_contours = num_contours;
  return error;
}

/*
*  The following is very similar to FT_Outline_Decompose, except
*  that we do support opened paths, and do not scale the outline.
*/
static s32 FT_Stroker_ParseOutline(FT_Stroker *stroker, GF_Path*  outline)
{
  GF_Point2D   v_last;
#if 0 //unused
  GF_Point2D   v_control;
#endif
  GF_Point2D   v_start;
  GF_Point2D*  point;
  GF_Point2D*  limit;
  u8 *tags;
  s32 error;
  u32 n;         /* index of contour in outline     */
  u32 first;     /* index of first point in contour */
  s32 tag;       /* current point's state           */

  if ( !outline || !stroker )
    return -1;

  first = 0;

  for ( n = 0; n < outline->n_contours; n++ ) {
    s32 closed_subpath;
    s32 last;  /* index of last point in contour */

    last  = outline->contours[n];
    limit = outline->points + last;

    v_start = outline->points[first];
    v_last  = outline->points[last];

#if 0 //unused
    v_control = v_start;
#endif

    point = outline->points + first;
    tags  = outline->tags  + first;
    tag = tags[0];

    /* A contour cannot start with a cubic control point! */
    if ( tag == GF_PATH_CURVE_CUBIC )
      goto Invalid_Outline;

    /* check first point to determine origin */
    if ( tag == GF_PATH_CURVE_CONIC ) {
      /* First point is conic control.  Yes, this happens. */
      if ( outline->tags[last] & GF_PATH_CURVE_ON ) {
        /* start at last point if it is on the curve */
        v_start = v_last;
        limit--;
      } else {
        /* if both first and last points are conic,         */
        /* start at their middle and record its position    */
        /* for closure                                      */
        v_start.x = ( v_start.x + v_last.x ) / 2;
        v_start.y = ( v_start.y + v_last.y ) / 2;
      }
      point--;
      tags--;
    }
    closed_subpath = (outline->tags[outline->contours[n]]==GF_PATH_CLOSE) ? 1 : 0;

    error = FT_Stroker_BeginSubPath(stroker, &v_start);
    if ( error )
      goto Exit;

    /*subpath is a single point, force a lineTo to start for the stroker to compute lineCap*/
    if (point==limit) {
      error = FT_Stroker_LineTo(stroker, &v_start, GF_TRUE);
      closed_subpath = 0;
      goto Close;
    }

    while ( point < limit ) {
      point++;
      tags++;

      tag = tags[0];
      switch ( tag ) {
      case GF_PATH_CURVE_ON:  /* emit a single line_to */
      case GF_PATH_CLOSE:  /* emit a single line_to */
      {
        GF_Point2D  vec;
        vec.x = point->x;
        vec.y = point->y;

        error = FT_Stroker_LineTo( stroker, &vec, (point == limit) ? GF_TRUE : GF_FALSE );
        if ( error )
          goto Exit;
        continue;
      }


#if 0 //unused
      case GF_PATH_CURVE_CONIC:  /* consume conic arcs */
        v_control.x = point->x;
        v_control.y = point->y;

Do_Conic:
        if ( point < limit ) {
          GF_Point2D  vec;
          GF_Point2D  v_middle;


          point++;
          tags++;
          tag = tags[0];

          vec = point[0];

          if ( tag & GF_PATH_CURVE_ON) {

            error = FT_Stroker_ConicTo( stroker, &v_control, &vec );
            if ( error )
              goto Exit;
            continue;
          }

          if ( tag != GF_PATH_CURVE_CONIC )
            goto Invalid_Outline;

          v_middle.x = ( v_control.x + vec.x ) / 2;
          v_middle.y = ( v_control.y + vec.y ) / 2;

          error = FT_Stroker_ConicTo( stroker, &v_control, &v_middle );
          if ( error )
            goto Exit;

          v_control = vec;
          goto Do_Conic;
        }
        error = FT_Stroker_ConicTo( stroker, &v_control, &v_start );
        goto Close;

      default:  /* GF_PATH_CURVE_CUBIC */
      {
        GF_Point2D  vec1, vec2;

        if ( point + 1 > limit                             ||
                tags[1] != GF_PATH_CURVE_CUBIC )
          goto Invalid_Outline;

        point += 2;
        tags  += 2;

        vec1 = point[-2];
        vec2 = point[-1];

        if ( point <= limit ) {
          GF_Point2D  vec;
          vec = point[0];

          error = FT_Stroker_CubicTo( stroker, &vec1, &vec2, &vec );
          if ( error )
            goto Exit;
          continue;
        }
        error = FT_Stroker_CubicTo( stroker, &vec1, &vec2, &v_start );
        goto Close;
      }
      break;
#else
      default:  /* GF_PATH_CURVE_CUBIC */
        GF_LOG(GF_LOG_ERROR, GF_LOG_CORE, ("[Path2DStroke] Path is not flatten, cannot strike cubic and quadratic !\n"));
#endif

      }
    }

Close:
    if ( error ) goto Exit;

    error = FT_Stroker_EndSubPath(stroker, closed_subpath);
    if ( error )
      goto Exit;

    first = last + 1;
  }
  return 0;

Exit:
  return error;

Invalid_Outline:
  return -1;
}






#define GF_PATH_DOT_LEN   1
#define GF_PATH_DOT_SPACE 2
#define GF_PATH_DASH_LEN  3

static Fixed gf_path_get_dash(GF_PenSettings *pen, u32 dash_slot, u32 *next_slot)
{
  Fixed ret = 0;
  switch (pen->dash) {
  case GF_DASH_STYLE_DOT:
    if (dash_slot==0) ret = GF_PATH_DOT_LEN;
    else if (dash_slot==1) ret = GF_PATH_DOT_SPACE;
    *next_slot = (dash_slot + 1) % 2;
    return ret * pen->width;
  case GF_DASH_STYLE_DASH:
    if (dash_slot==0) ret = GF_PATH_DASH_LEN;
    else if (dash_slot==1) ret = GF_PATH_DOT_SPACE;
    *next_slot = (dash_slot + 1) % 2;
    return ret * pen->width;
  case GF_DASH_STYLE_DASH_DOT:
    if (dash_slot==0) ret = GF_PATH_DASH_LEN;
    else if (dash_slot==1) ret = GF_PATH_DOT_SPACE;
    else if (dash_slot==2) ret = GF_PATH_DOT_LEN;
    else if (dash_slot==3) ret = GF_PATH_DOT_SPACE;
    *next_slot = (dash_slot + 1) % 4;
    return ret * pen->width;
  case GF_DASH_STYLE_DASH_DASH_DOT:
    if (dash_slot==0) ret = GF_PATH_DASH_LEN;
    else if (dash_slot==1) ret = GF_PATH_DOT_SPACE;
    else if (dash_slot==2) ret = GF_PATH_DASH_LEN;
    else if (dash_slot==3) ret = GF_PATH_DOT_SPACE;
    else if (dash_slot==4) ret = GF_PATH_DOT_LEN;
    else if (dash_slot==5) ret = GF_PATH_DOT_SPACE;
    *next_slot = (dash_slot + 1) % 6;
    return ret * pen->width;
  case GF_DASH_STYLE_DASH_DOT_DOT:
    if (dash_slot==0) ret = GF_PATH_DASH_LEN;
    else if (dash_slot==1) ret = GF_PATH_DOT_SPACE;
    else if (dash_slot==2) ret = GF_PATH_DOT_LEN;
    else if (dash_slot==3) ret = GF_PATH_DOT_SPACE;
    else if (dash_slot==4) ret = GF_PATH_DOT_LEN;
    else if (dash_slot==5) ret = GF_PATH_DOT_SPACE;
    *next_slot = (dash_slot + 1) % 6;
    return ret * pen->width;
  case GF_DASH_STYLE_CUSTOM:
  case GF_DASH_STYLE_SVG:
    if (!pen->dash_set || !pen->dash_set->num_dash) return 0;
    if (dash_slot>=pen->dash_set->num_dash) dash_slot = 0;
    ret = pen->dash_set->dashes[dash_slot];
    *next_slot = (1 + dash_slot) % pen->dash_set->num_dash;
    if (pen->dash==GF_DASH_STYLE_SVG) return ret;
    /*custom dashes are of type Fixed !!*/
    return gf_mulfix(ret, pen->width);

  default:
  case GF_DASH_STYLE_PLAIN:
    *next_slot = 0;
    return 0;
  }
}


/* Credits go to Raph Levien for libart / art_vpath_dash */

/* FIXEME - NOT DONE - Merge first and last subpaths when first and last dash segment are joined a closepath. */
static GF_Err gf_path_mergedashes(GF_Path *gp, u32 start_contour_index)
{
  u32 i, dash_first_pt, dash_nb_pts;
  if (start_contour_index) {
    dash_nb_pts = gp->contours[start_contour_index] - gp->contours[start_contour_index-1];
    dash_first_pt = gp->contours[start_contour_index-1]+1;
  } else {
    dash_nb_pts = gp->contours[start_contour_index]+1;
    dash_first_pt = 0;
  }
  /*skip first point of first dash in subpath (same as last point of last dash)*/
  for (i=1; i<dash_nb_pts; i++) {
    GF_Err e = gf_path_add_line_to_vec(gp, &gp->points[dash_first_pt + i]);
    if (e) return e;
  }
  /*remove initial dash*/
  gp->n_points -= dash_nb_pts;
  memmove(gp->points + dash_first_pt, gp->points + dash_first_pt + dash_nb_pts, sizeof(GF_Point2D)*(gp->n_points - dash_first_pt));
  memmove(gp->tags + dash_first_pt, gp->tags + dash_first_pt + dash_nb_pts, sizeof(u8)*(gp->n_points - dash_first_pt));

  for (i=start_contour_index; i<gp->n_contours-1; i++) {
    gp->contours[i] = gp->contours[i+1] - dash_nb_pts;
  }
  gp->n_contours--;
  gp->contours = (u32 *)gf_realloc(gp->contours, sizeof(u32)*gp->n_contours);

  /*
    gp->points = gf_realloc(gp->points, sizeof(GF_Point2D)*gp->n_points);
    gp->tags = gf_realloc(gp->tags, sizeof(u8)*gp->n_points);
    gp->n_alloc_points = gp->n_points;
  */
  return GF_OK;
}

static GF_Err evg_dash_subpath(GF_Path *dashed, GF_Point2D *pts, u32 nb_pts, GF_PenSettings *pen, Fixed length_scale)
{
  Fixed *dists;
  Fixed totaldist;
  Fixed dash;
  Fixed dist;
  Fixed dash_dist;
  s32 offsetinit;
  u32 next_offset=0;
  s32 toggleinit;
  s32 firstindex;
  Bool toggle_check;
  GF_Err e;
  u32 i, start_ind;
  Fixed phase;
  s32 offset, toggle;

  dists = (Fixed *)gf_malloc(sizeof (Fixed) * nb_pts);
  if (dists == NULL) return GF_OUT_OF_MEM;

  /* initial values */
  toggleinit = 1;
  offsetinit = 0;
  dash_dist = 0;

  dash = gf_path_get_dash(pen, offsetinit, &next_offset);
  if (length_scale) dash = gf_mulfix(dash, length_scale);
  firstindex = -1;
  toggle_check = GF_FALSE;

  start_ind = 0;
  dist = 0;

  /*SVG dashing is different from BIFS one*/
  if (pen->dash==GF_DASH_STYLE_SVG) {
    while (pen->dash_offset>0) {
      if (pen->dash_offset - dash < 0) {
        dash -= pen->dash_offset;
        pen->dash_offset = 0;
        break;
      }
      pen->dash_offset -= dash;
      offsetinit = next_offset;
      toggleinit = !toggleinit;
      dash = gf_path_get_dash(pen, offsetinit, &next_offset);
      if (length_scale) dash = gf_mulfix(dash, length_scale);
    }
    if ((pen->dash_offset<0) && pen->dash_set && pen->dash_set->num_dash) {
      offsetinit = pen->dash_set->num_dash-1;
      dash = gf_path_get_dash(pen, offsetinit, &next_offset);
      if (length_scale) dash = gf_mulfix(dash, length_scale);
      while (pen->dash_offset<0) {
        toggleinit = !toggleinit;
        if (pen->dash_offset + dash > 0) {
          dash_dist = dash+pen->dash_offset;
          pen->dash_offset = 0;
          break;
        }
        pen->dash_offset += dash;
        if (offsetinit) offsetinit --;
        else offsetinit = pen->dash_set->num_dash-1;
        dash = gf_path_get_dash(pen, offsetinit, &next_offset);
        if (length_scale) dash = gf_mulfix(dash, length_scale);
      }
    }
  }

  /* calculate line lengths and update offset*/
  totaldist = 0;
  for (i = 0; i < nb_pts - 1; i++) {
    GF_Point2D diff;
    diff.x = pts[i+1].x - pts[i].x;
    diff.y = pts[i+1].y - pts[i].y;
    dists[i] = gf_v2d_len(&diff);

    if (pen->dash_offset > dists[i]) {
      pen->dash_offset -= dists[i];
      dists[i] = 0;
    }
    else if (pen->dash_offset) {
      Fixed a, x, y, dx, dy;

      a = gf_divfix(pen->dash_offset, dists[i]);
      dx = pts[i + 1].x - pts[i].x;
      dy = pts[i + 1].y - pts[i].y;
      x = pts[i].x + gf_mulfix(a, dx);
      y = pts[i].y + gf_mulfix(a, dy);
      e = gf_path_add_move_to(dashed, x, y);
      if (e) goto err_exit;
      totaldist += dists[i];
      dist = pen->dash_offset;
      pen->dash_offset = 0;
      start_ind = i;
    } else {
      totaldist += dists[i];
    }
  }
  dash -= dash_dist;

  /* subpath fits within first dash and no offset*/
  if (!dist && totaldist <= dash) {
    if (toggleinit) {
      gf_path_add_move_to_vec(dashed, &pts[0]);
      for (i=1; i<nb_pts; i++) {
        gf_path_add_line_to_vec(dashed, &pts[i]);
      }
    }
    gf_free(dists);
    return GF_OK;
  }

  /* subpath is composed of at least one dash */
  phase = 0;
  toggle = toggleinit;
  i = start_ind;

  if (toggle && !dist) {
    e = gf_path_add_move_to_vec(dashed, &pts[i]);
    if (e) goto err_exit;
    firstindex = dashed->n_contours - 1;
  }

  while (i < nb_pts - 1) {
    /* dash boundary is next */
    if (dists[i] - dist > dash - phase) {
      Fixed a, x, y, dx, dy;
      dist += dash - phase;
      a = gf_divfix(dist, dists[i]);
      dx = pts[i + 1].x - pts[i].x;
      dy = pts[i + 1].y - pts[i].y;
      x = pts[i].x + gf_mulfix(a, dx);
      y = pts[i].y + gf_mulfix(a, dy);

      if (!toggle_check || ((x != pts[i].x) || (y != pts[i].y))) {
        if (toggle) {
          e = gf_path_add_line_to(dashed, x, y);
          if (e) goto err_exit;
        }
        else {
          e = gf_path_add_move_to(dashed, x, y);
          if (e) goto err_exit;
        }
      }

      /* advance to next dash */
      toggle = !toggle;
      phase = 0;
      offset = next_offset;
      dash = gf_path_get_dash(pen, offset, &next_offset);
      if (length_scale) dash = gf_mulfix(dash, length_scale);
    }
    /* end of line in subpath is next */
    else {
      phase += dists[i] - dist;
      i ++;
      toggle_check = GF_FALSE;
      dist = 0;
      if (toggle) {
        e = gf_path_add_line_to_vec(dashed, &pts[i]);
        if (e) goto err_exit;
        toggle_check = GF_TRUE;

        if ( (firstindex>=0) && (i == (nb_pts - 1) && ((firstindex + 1) != (s32) start_ind ) ))  {
          /*merge if closed path*/
          if ((pts[0].x==pts[nb_pts-1].x) && (pts[0].y==pts[nb_pts-1].y)) {
            e = gf_path_mergedashes(dashed, firstindex);
            if (e) goto err_exit;
          }
        }
      }
    }
  }

err_exit:
//  pen->dash_offset = dist;
  gf_free(dists);
  return GF_OK;
}

static GF_Path *gf_path_dash(GF_Path *path, GF_PenSettings *pen)
{
  u32 i, j, nb_pts;
  GF_Point2D *pts;
  Fixed length_scale = 0;
  Fixed dash_off = pen->dash_offset;
  GF_Path *dashed = gf_path_new();


  /* calculate line lengths and update offset*/
  if (pen->path_length>0) {
    Fixed totaldist = 0;
    nb_pts = 0;
    for (i=0; i<path->n_contours; i++) {
      pts = &path->points[nb_pts];
      nb_pts = 1+path->contours[i] - nb_pts;

      for (j=0; j<nb_pts-1; j++) {
        GF_Point2D diff;
        diff.x = pts[j+1].x - pts[j].x;
        diff.y = pts[j+1].y - pts[j].y;
        totaldist += gf_v2d_len(&diff);
      }
      nb_pts = 1+path->contours[i];
    }
    length_scale = gf_divfix(totaldist, pen->path_length);
    pen->dash_offset = gf_mulfix(pen->dash_offset, length_scale);
  }

  nb_pts = 0;
  for (i=0; i<path->n_contours; i++) {
    pts = &path->points[nb_pts];
    nb_pts = 1+path->contours[i] - nb_pts;
    evg_dash_subpath(dashed, pts, nb_pts, pen, length_scale);
    nb_pts = 1+path->contours[i];
//    if (length_scale) pen->dash_offset = gf_mulfix(pen->dash_offset, length_scale);
  }
  pen->dash_offset = dash_off;
  dashed->flags |= GF_PATH_FILL_ZERO_NONZERO;
  return dashed;
}

GF_EXPORT
GF_Path *gf_path_get_outline(GF_Path *path, GF_PenSettings pen)
{
  s32 error;
  GF_Path *outline;
  GF_Path *dashed;
  GF_Path *scaled;
  FT_Stroker stroker;
  if (!path || !pen.width) return NULL;

  memset(&stroker, 0, sizeof(stroker));
  stroker.borders[0].start = -1;
  stroker.borders[1].start = -1;
  stroker.line_cap = pen.cap;
  stroker.line_join = pen.join;
  stroker.miter_limit = pen.miterLimit;
  stroker.radius = pen.width/2;

  gf_path_flatten(path);

  scaled = NULL;
  /*if not centered, simply scale path...*/
  if (pen.align) {
    Fixed sx, sy;
    GF_Rect bounds;
    gf_path_get_bounds(path, &bounds);
    if (pen.align==GF_PATH_LINE_OUTSIDE) {
      sx = gf_divfix(bounds.width+pen.width, bounds.width);
      sy = gf_divfix(bounds.height+pen.width, bounds.height);
    } else {
      /*note: this may result in negative scaling, not our pb but the author's one*/
      sx = gf_divfix(bounds.width-pen.width, bounds.width);
      sy = gf_divfix(bounds.height-pen.width, bounds.height);
    }
    if (sx && sy) {
      u32 i;
      scaled = gf_path_clone(path);
      for (i=0; i<scaled->n_points; i++) {
        scaled->points[i].x = gf_mulfix(scaled->points[i].x, sx);
        scaled->points[i].y = gf_mulfix(scaled->points[i].y, sy);
      }
      path = scaled;
    }
  }

  /*if dashing, first flatten path then dash all segments*/
  dashed = NULL;
  /*security, seen in some SVG files*/
  if (pen.dash_set && (pen.dash_set->num_dash==1) && (pen.dash_set->dashes[0]==0)) pen.dash = GF_DASH_STYLE_PLAIN;
  if (pen.dash) {
    GF_Path *flat;
    flat = gf_path_get_flatten(path);
    if (!flat) return NULL;
    dashed = gf_path_dash(flat, &pen);
    gf_path_del(flat);
    if (!dashed) return NULL;
    path = dashed;
  }

  outline = NULL;
  error = FT_Stroker_ParseOutline(&stroker, path);
  if (!error) {
    u32 nb_pt, nb_cnt;
    error = FT_Stroker_GetCounts(&stroker, &nb_pt, &nb_cnt);
    if (!error) {
      outline = gf_path_new();
      if (nb_pt) {
        FT_StrokeBorder sborder;
        outline->points = (GF_Point2D *) gf_malloc(sizeof(GF_Point2D)*nb_pt);
        outline->tags = (u8 *) gf_malloc(sizeof(u8)*nb_pt);
        outline->contours = (u32 *) gf_malloc(sizeof(u32)*nb_cnt);
        outline->n_alloc_points = nb_pt;
        sborder = &stroker.borders[0];
        if (sborder->valid ) ft_stroke_border_export(sborder, outline);
        sborder = &stroker.borders[1];
        /*if left border is valid this is a closed path, used odd/even rule - we will have issues at recovering
        segments...*/
        if (sborder->valid && sborder->num_points) {
          ft_stroke_border_export(sborder, outline);
        }
        /*otherwise this is an open path, use zero/non-zero*/
        else {
          outline->flags |= GF_PATH_FILL_ZERO_NONZERO;
        }
      }
      outline->flags |= GF_PATH_BBOX_DIRTY;

      /*our caps are cubic bezier!!*/
      if ( (path->flags & GF_PATH_FLATTENED) && (pen.cap!=GF_LINE_CAP_ROUND) && (pen.join!=GF_LINE_JOIN_ROUND) )
        outline->flags |= GF_PATH_FLATTENED;
    }
  }

  if (stroker.borders[0].points) gf_free(stroker.borders[0].points);
  if (stroker.borders[0].tags) gf_free(stroker.borders[0].tags);
  if (stroker.borders[1].points) gf_free(stroker.borders[1].points);
  if (stroker.borders[1].tags) gf_free(stroker.borders[1].tags);

  if (dashed) gf_path_del(dashed);
  if (scaled) gf_path_del(scaled);

  return outline;
}

#endif //GPAC_DISABLE_EVG

Coverage Report

Created: 2026-04-12 08:39