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path.cpp

/*
 * Path - Series of continuous curves
 *   
 * Copyright 2007  MenTaLguY <mental@rydia.net>
 *     
 * This library is free software; you can redistribute it and/or 
 * modify it either under the terms of the GNU Lesser General Public
 * License version 2.1 as published by the Free Software Foundation
 * (the "LGPL") or, at your option, under the terms of the Mozilla
 * Public License Version 1.1 (the "MPL"). If you do not alter this 
 * notice, a recipient may use your version of this file under either
 * the MPL or the LGPL.
 *            
 * You should have received a copy of the LGPL along with this library
 * in the file COPYING-LGPL-2.1; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 * You should have received a copy of the MPL along with this library 
 * in the file COPYING-MPL-1.1
 *                
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *                   
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
 * the specific language governing rights and limitations.
 */

#include "path.h"

#include "ord.h"

namespace Geom {

int CurveHelpers::root_winding(Curve const &c, Point p) {
    std::vector<double> ts = c.roots(p[Y], Y);

    if(ts.empty()) return 0;

    double const fudge = 0.01; //fudge factor used on first and last

    std::sort(ts.begin(), ts.end());

    // winding determined by crossings at roots
    int wind=0;
    // previous time
    double pt = ts.front() - fudge;
    for ( std::vector<double>::iterator ti = ts.begin()
        ; ti != ts.end()
        ; ++ti )
    {
        double t = *ti;
        if ( t <= 0. || t >= 1. ) continue; //skip endpoint roots 
        if ( c.valueAt(t, X) > p[X] ) { // root is ray intersection
            // Get t of next:
            std::vector<double>::iterator next = ti;
            next++;
            double nt;
            if(next == ts.end()) nt = t + fudge; else nt = *next;
            
            // Check before in time and after in time for positions
            // Currently we're using the average times between next and previous segs
            Cmp after_to_ray =  cmp(c.valueAt((t + nt) / 2, Y), p[Y]);
            Cmp before_to_ray = cmp(c.valueAt((t + pt) / 2, Y), p[Y]);
            // if y is included, these will have opposite values, giving order.
            Cmp dt = cmp(after_to_ray, before_to_ray);
            if(dt != EQUAL_TO) //Should always be true, but yah never know..
                wind += dt;
            pt = t;
        }
    }
    
    return wind;
}

void Path::swap(Path &other) {
  std::swap(curves_, other.curves_);
  std::swap(closed_, other.closed_);
  std::swap(*final_, *other.final_);
  curves_[curves_.size()-1] = final_;
  other.curves_[other.curves_.size()-1] = other.final_;
}

Rect Path::boundsFast() const {
  Rect bounds=front().boundsFast();
  for ( const_iterator iter=++begin(); iter != end() ; ++iter ) {
    bounds.unionWith(iter->boundsFast());
  }
  return bounds;
}

Rect Path::boundsExact() const {
  Rect bounds=front().boundsExact();
  for ( const_iterator iter=++begin(); iter != end() ; ++iter ) {
    bounds.unionWith(iter->boundsExact());
  }
  return bounds;
}

template<typename iter>
iter inc(iter const &x, unsigned n) {
  iter ret = x;
  for(unsigned i = 0; i < n; i++)
    ret++;
  return ret;
}

//This assumes that you can't be perfect in your t-vals, and as such, tweaks the start
void Path::appendPortionTo(Path &ret, double from, double to) const {
  assert(from >= 0 && to >= 0);
  if(to == 0) to = size()+0.999999;
  if(from == to) { return; }
  double fi, ti;
  double ff = modf(from, &fi), tf = modf(to, &ti);
  if(tf == 0) { ti--; tf = 1; }
  const_iterator fromi = inc(begin(), (unsigned)fi);
  if(fi == ti && from < to) {
    Curve *v = fromi->portion(ff, tf);
    ret.append(*v);
    delete v;
    return;
  }
  const_iterator toi = inc(begin(), (unsigned)ti);
  if(ff != 1.) {
    Curve *fromv = fromi->portion(ff, 1.);
    //fromv->setInitial(ret.finalPoint());
    ret.append(*fromv);
    delete fromv;
  }
  if(from >= to) {
    const_iterator ender = end();
    if(ender->initialPoint() == ender->finalPoint()) ender++;
    ret.insert(ret.end(), ++fromi, ender);
    ret.insert(ret.end(), begin(), toi);
  } else {
    ret.insert(ret.end(), ++fromi, toi);
  }
  Curve *tov = toi->portion(0., tf);
  ret.append(*tov);
  delete tov;
}

const double eps = .1;

void Path::append(Curve const &curve) {
  if ( curves_.front() != final_ && !are_near(curve.initialPoint(), (*final_)[0], eps) ) {
    throwContinuityError();
  }
  do_append(curve.duplicate());
}

void Path::append(D2<SBasis> const &curve) {
  if ( curves_.front() != final_ ) {
    for ( int i = 0 ; i < 2 ; ++i ) {
      if ( !are_near(curve[i][0][0], (*final_)[0][i], eps) ) {
        throwContinuityError();
      }
    }
  }
  do_append(new SBasisCurve(curve));
}

void Path::do_update(Sequence::iterator first_replaced,
                     Sequence::iterator last_replaced,
                     Sequence::iterator first,
                    Sequence::iterator last)
{
  // note: modifies the contents of [first,last)

  check_continuity(first_replaced, last_replaced, first, last);
  delete_range(first_replaced, last_replaced);
  if ( ( last - first ) == ( last_replaced - first_replaced ) ) {
    std::copy(first, last, first_replaced);
  } else {
    // this approach depends on std::vector's behavior WRT iterator stability
    curves_.erase(first_replaced, last_replaced);
    curves_.insert(first_replaced, first, last);
  }

  if ( curves_.front() != final_ ) {
    final_->setPoint(0, back().finalPoint());
    final_->setPoint(1, front().initialPoint());
  }
}

void Path::do_append(Curve *curve) {
  if ( curves_.front() == final_ ) {
    final_->setPoint(1, curve->initialPoint());
  }
  curves_.insert(curves_.end()-1, curve);
  final_->setPoint(0, curve->finalPoint());
}

void Path::delete_range(Sequence::iterator first, Sequence::iterator last) {
  for ( Sequence::iterator iter=first ; iter != last ; ++iter ) {
    delete *iter;
  }
}

void Path::check_continuity(Sequence::iterator first_replaced,
                            Sequence::iterator last_replaced,
                            Sequence::iterator first,
                            Sequence::iterator last)
{
  if ( first != last ) {
    if ( first_replaced != curves_.begin() ) {
      if ( !are_near( (*first_replaced)->initialPoint(), (*first)->initialPoint(), eps ) ) {
        throwContinuityError();
      }
    }
    if ( last_replaced != (curves_.end()-1) ) {
      if ( !are_near( (*(last_replaced-1))->finalPoint(), (*(last-1))->finalPoint(), eps ) ) {
        throwContinuityError();
      }
    }
  } else if ( first_replaced != last_replaced && first_replaced != curves_.begin() && last_replaced != curves_.end()-1) {
    if ( !are_near((*first_replaced)->initialPoint(), (*(last_replaced-1))->finalPoint(), eps ) ) {
      throwContinuityError();
    }
  }
}

Rect SVGEllipticalArc::boundsFast() const {
    throwNotImplemented();
}
Rect SVGEllipticalArc::boundsExact() const {
    throwNotImplemented();
}
Rect SVGEllipticalArc::boundsLocal(Interval i, unsigned deg) const {
    throwNotImplemented();
}

std::vector<Point> SVGEllipticalArc::pointAndDerivatives(Coord t, unsigned n) const {
    throwNotImplemented();
}

std::vector<double> SVGEllipticalArc::roots(double v, Dim2 d) const {
    throwNotImplemented();
}

D2<SBasis> SVGEllipticalArc::toSBasis() const {
    return D2<SBasis>(Linear(initial_[X], final_[X]), Linear(initial_[Y], final_[Y]));
}

}

/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(substatement-open . 0))
  indent-tabs-mode:nil
  c-brace-offset:0
  fill-column:99
  End:
  vim: filetype=cpp:expandtab:shiftwidth=2:tabstop=8:softtabstop=2 :
*/

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