remove_rectangle_overlap.cpp

/**
 * \brief remove overlaps between a set of rectangles.
 *
 * Authors:
 *   Tim Dwyer <tgdwyer@gmail.com>
 *
 * Copyright (C) 2005 Authors
 *
 * Released under GNU LGPL.  Read the file 'COPYING' for more information.
 */

#include <iostream>
#include <cassert>
#include "generate-constraints.h"
#include "solve_VPSC.h"
#include "variable.h"
#include "constraint.h"
#ifdef RECTANGLE_OVERLAP_LOGGING
#include <fstream>
#include "blocks.h"
using std::ios;
using std::ofstream;
using std::endl;
#endif

#define EXTRA_GAP 0.0001
using namespace vpsc;

double Rectangle::xBorder=0;
double Rectangle::yBorder=0;
/**
 * Takes an array of n rectangles and moves them as little as possible
 * such that rectangles are separated by at least xBorder horizontally
 * and yBorder vertically
 *
 * Works in three passes: 
 * 1) removes some overlap horizontally
 * 2) removes remaining overlap vertically
 * 3) a last horizontal pass removes all overlap starting from original
 *    x-positions - this corrects the case where rectangles were moved 
 *    too much in the first pass.
 */
void removeRectangleOverlap(unsigned n, Rectangle *rs[], double xBorder, double yBorder) {
      try {
      // The extra gap avoids numerical imprecision problems
      Rectangle::setXBorder(xBorder+EXTRA_GAP);
      Rectangle::setYBorder(yBorder+EXTRA_GAP);
      Variable **vs=new Variable*[n];
      for(unsigned i=0;i<n;i++) {
            vs[i]=new Variable(i,0,1);
      }
      Constraint **cs;
      double *oldX = new double[n];
      unsigned m=generateXConstraints(n,rs,vs,cs,true);
      for(unsigned i=0;i<n;i++) {
            oldX[i]=vs[i]->desiredPosition;
      }
      Solver vpsc_x(n,vs,m,cs);
#ifdef RECTANGLE_OVERLAP_LOGGING
      ofstream f(LOGFILE,ios::app);
      f<<"Calling VPSC: Horizontal pass 1"<<endl;
      f.close();
#endif
      vpsc_x.solve();
      for(unsigned i=0;i<n;i++) {
            rs[i]->moveCentreX(vs[i]->position());
      }
      for(unsigned i = 0; i < m; ++i) {
            delete cs[i];
      }
      delete [] cs;
      // Removing the extra gap here ensures things that were moved to be adjacent to
      // one another above are not considered overlapping
      Rectangle::setXBorder(Rectangle::xBorder-EXTRA_GAP);
      m=generateYConstraints(n,rs,vs,cs);
      Solver vpsc_y(n,vs,m,cs);
#ifdef RECTANGLE_OVERLAP_LOGGING
      f.open(LOGFILE,ios::app);
      f<<"Calling VPSC: Vertical pass"<<endl;
      f.close();
#endif
      vpsc_y.solve();
      for(unsigned i=0;i<n;i++) {
            rs[i]->moveCentreY(vs[i]->position());
            rs[i]->moveCentreX(oldX[i]);
      }
      delete [] oldX;
      for(unsigned i = 0; i < m; ++i) {
            delete cs[i];
      }
      delete [] cs;
      Rectangle::setYBorder(Rectangle::yBorder-EXTRA_GAP);
      m=generateXConstraints(n,rs,vs,cs,false);
      Solver vpsc_x2(n,vs,m,cs);
#ifdef RECTANGLE_OVERLAP_LOGGING
      f.open(LOGFILE,ios::app);
      f<<"Calling VPSC: Horizontal pass 2"<<endl;
      f.close();
#endif
      vpsc_x2.solve();
      for(unsigned i = 0; i < m; ++i) {
            delete cs[i];
      }
      delete [] cs;
      for(unsigned i=0;i<n;i++) {
            rs[i]->moveCentreX(vs[i]->position());
            delete vs[i];
      }
      delete [] vs;
      } catch (char const *str) {
            std::cerr<<str<<std::endl;
            for(unsigned i=0;i<n;i++) {
                  std::cerr << *rs[i]<<std::endl;
            }
      }
}