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Clipper.h

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/******************************** LICENSE ********************************

 Copyright 2007 European Centre for Medium-Range Weather Forecasts (ECMWF)

 Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.

 ******************************** LICENSE ********************************/

/*! \file Clipper.h
    \brief Definition of the clipping.
    \author Graphics Section, ECMWF

    Started: 2004

*/ 

#ifndef Clipper_H
#define Clipper_H

#include "magics.h"
#include "PolyCoast.h"
#include "Transformation.h"

namespace magics {

template <class P> 
class Push 
{
public:
      Push(Polyline& poly) : poly_(poly) {}
      ~Push() {}
      void operator()(P& point) { poly_.push_back(point); }
protected:
      Polyline& poly_;
};


template <class P>
bool clockwise(Polyline& c) {
        double area = 0 ;
        if(c.size()) c.push_back(c[0]);

        for(unsigned int j = 0; j < c.size(); j++)
        {
                if(j) area += ( c[j-1].x() * c[j].y() -
                                c[j].x()   * c[j-1].y() );
        }
        if(c.size()) c.pop_back();
        return area < 0;
}

template <class P>
class Empty
{
public:
   Empty() {}
   ~Empty() {}
   bool operator()(const Polyline* poly)
   {
      if ( poly->empty() ) {
        delete poly;
        return true;
      }
      return false;
   }
};


template <class C>
class Clipper
{
public:
      Clipper(const Transformation& transformation) : 
            lastX_(int_MIN), lastY_(int_MIN), 
            lastIn_(false),  current_(0), 
            transformation_(transformation),
            missing_(true) 
      {
            left_ = std::min(transformation_.getMinPCX(), transformation_.getMaxPCX());
            right_ = std::max(transformation_.getMinPCX(), transformation_.getMaxPCX());
            top_ = std::max(transformation_.getMinPCY(), transformation_.getMaxPCY());
            bottom_ = std::min(transformation_.getMinPCY(), transformation_.getMaxPCY());
      }
      ~Clipper() {}
      
      void feed(C& out) { 
            for(  vector<Polyline* >::iterator line = helper_.begin(); line != helper_.end(); ++line) {
                  if ( (*line)->getShading() ) {
                        (*line)->setFilled(true);
                  
                  }
                  out.push_back(*line);
            }
      }
      void adjust(double left, double bottom, double right, double top) {
            left_ = left;
            right_ = right;
            top_ = top;
            bottom_ = bottom;
      }

    bool pointin_;
    void close(PolyCoast& poly)
    {
      // Fisrt we reproject! 
      current_ = poly.getShade();
      
      if ( current_ ) { 
            vector<GeoPoint>& geo = poly.coastlines();
            pointin_ = false;
            for ( vector<GeoPoint>::const_iterator point = geo.begin(); point != geo.end(); ++point)              
                  close(transformation_(*point));
            current_->push_back(current_->front());         
             helper_.push_back(current_);
      }

      current_ = poly.getContour();
      vector<GeoPoint>& geo = poly.coastlines();      
      for ( vector<GeoPoint>::const_iterator point = geo.begin(); point != geo.end(); ++point)              
            (*this)( transformation_(*point));                    
        if ( !current_->empty() ) {
              helper_.push_back(current_); 
        }
        else 
              delete current_; // Was allocated for nothing!
    }
      

    void operator()(const Polyline& poly)
    {
      //if  ( poly.allMissing() ) return;
        current_ = new Polyline();   
      current_->copy(poly);   
      lastX_ = int_MIN;
      lastY_ = int_MIN; 
            lastIn_ = false;
      value_ = poly.front().value();
      allmissing_ = poly.allMissing();
        static int i = 0;
        i++;

        // Useful print to debug clipping problems...
        //Log::dev()<< "[" << poly.front().x() << ", " << poly.front().y() << "]--->[" <<  poly.back().x() << ", " << poly.back().y() << "] at " << i << " with " << poly.size() << " points" << endl;
      //if ( i != 1 )
            //return;

            transformation_.wrapAround(poly);

      /*Polyline projected;
          typename Polyline::const_iterator point = poly.begin();
      for ( ; point != poly.end(); ++point) {
            //if (i == 1) Log::dev()<< "[" << point->x() << ", " << point->y() << "]" << endl;
            projected.push_back(*point);
      }
      */
      
      
      for ( Polyline::const_iterator point = poly.begin(); point != poly.end(); ++point) {
            //PaperPoint clip = *point;
            //transformation_.clip(clip);
            (*this)(*point);
      }
      
      
      if ( !transformation_.concatenate(helper_, current_) ) 
                  helper_.push_back(current_);
    }
   

      void ignoreMissing(bool missing = true) { missing_ = !missing; }
 
      MAGICS_NO_EXPORT bool in(double x, double y) const
      {
            return ((y <= top_ && y >= bottom_) && (x >= left_ && x <= right_));
      }

#define A(x1, y1, x2, y2) (y2 -y1)/(x2-x1)
#define B(a, x, y) (y - a * x)
#define X(a, b, y) ((y - b)/a)
#define Y(a, b, x) ((a * x) + b)

    MAGICS_NO_EXPORT void push_intersection(double x, double y) 
    {
        if (lastX_ == int_MIN) return;

        double a = (lastX_ == x) ? 0 : A(lastX_, lastY_, x, y);
        double b = B(a, x, y);

        // Intersect left?
        if  ( (x <= left_ && lastX_ >= left_) || (lastX_ <= left_ && x >= left_) )
      {
            current_->push_back(PaperPoint(left_, Y(a, b, left_), value_, allmissing_));
            return;
        }
        // Intersect top?
    if  ( (y <= top_ && lastY_ >= top_) || ( lastY_ >= bottom_ && lastY_ <= top_ && y >= top_) )
      {
        double nx = (!a) ? x : X(a, b, top_);
        
        if ( nx > right_ ) nx = right_;
        if ( nx < left_ ) nx = left_;
            
        current_->push_back(PaperPoint(nx, top_, value_, allmissing_));
            
                return;
      }

        // Intersect right?
        if ( (x <= right_ && lastX_ >= right_) || (lastX_ <= right_ && x >= right_) )
      {
            current_->push_back(PaperPoint(right_, Y(a, b, right_), value_, allmissing_));
            return;
        }

        // intersect bottom?
        if ( (y <= bottom_ && lastY_ >= bottom_ && lastY_ <= top_ ) || ( lastY_ <= bottom_ && y >= bottom_) )
      {
            if (!a ) current_->push_back(PaperPoint(x, bottom_));
            else current_->push_back(PaperPoint(X(a, b, bottom_), bottom_, value_, allmissing_));
            return;
        }
    }

    MAGICS_NO_EXPORT void operator()(const PaperPoint& point)
    {
      if (missing_ && point.missing () && !current_->empty()) {
            if ( !transformation_.concatenate(helper_, current_) ) 
                  helper_.push_back(current_);
            Polyline* poly = new Polyline();
            poly->copy(*current_);            
            current_ = poly;
            //out_.push_back(current_);
            return;
      }

        if ( in(point.x(), point.y()) ) {
            if (lastIn_ ) {
                current_->push_back(point);
                lastX_ = point.x();
                lastY_ = point.y();
                        lastIn_ = true;
                return;
            }
            else {
                // We are entering the area ..
                // find intersection -->Push intersection + point... 
                  current_->clear();
                lastIn_ = true;
                push_intersection(point.x(), point.y());
                current_->push_back(point);
                lastX_ = point.x();
                lastY_ = point.y();
            
                return; 
            }
            return;
        }
      
        // Point is out 
        
        if (current_->empty()) {
            lastX_ = point.x();
            lastY_ = point.y();
            lastIn_ = false; 
          
            return;
        }
        // Why?
//        if (current_->size() == 1 ) {
//          current_->clear();
//            lastX_ = point.x();
//            lastY_ = point.y();
//            lastIn_ = false; 
//        
//            return;
//        }
        
        if (!lastIn_) { 
             lastX_ = point.x();
             lastY_ = point.y();
            return;
        }
        else {
            // push_back intersection
            push_intersection(point.x(), point.y());
            lastX_ = current_->back().x();
            lastY_ = current_->back().y();
            // create new Polyline...
           Polyline* poly = new Polyline();
            if ( !transformation_.concatenate(helper_, current_) ) 
                  helper_.push_back(current_);
            poly->copy(*current_);  
            current_ = poly;
            lastIn_ = false;
        }
        return;
     }
    
    //! Only used for coastlines
    MAGICS_NO_EXPORT void close(const PaperPoint& point)
    {
        if ( in(point.x(), point.y()) ) {
           if ( !pointin_ ) {
              push_intersection(point.x(), point.y());
           }
           current_->push_back(point);

           pointin_ = true;
        }
      
        // first point is out!
        else {
          if ( pointin_) {
             // We have to calculate the intersction
             lastX_ = current_->back().x();
             lastY_ = current_->back().y();
             push_intersection(point.x(), point.y());
          }
          else {
             double x =  point.x();
             double y =  point.y();
             lastX_ = x;
             lastY_ = y;

             x = std::min(x, right_);
             x = std::max(x, left_);
             y = std::min(y, top_);
             y = std::max(y, bottom_);
             current_->push_back(PaperPoint(x, y, value_, allmissing_));
          }
          pointin_ = false;
        }
    }
    
    MAGICS_NO_EXPORT void clip(const PaperPoint& point)
    {
        // ONly used for coastlines!
        if ( in(point.x(), point.y()) ) {
          current_->push_back(point);
        }
        else {
          if ( !current_->empty() ) {
              helper_.push_back(current_);
              current_ = current_->getNew();
          }
        }
    }

private:
    double left_;
    double bottom_;
    double right_;
    double top_;
    double lastX_;
    double lastY_;
    bool lastIn_;

    Polyline* current_;
    const Transformation& transformation_;
    vector<Polyline* > helper_;
    bool missing_;

    double value_;
    bool allmissing_;
};

}
#endif

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