lpe-knot.h

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// SPDX-License-Identifier: GPL-2.0-or-later
/* Authors:
 *   Jean-Francois Barraud <jf.barraud@gmail.com>
 *   Johan Engelen <j.b.c.engelen@alumnus.utwente.nl>
 *
 * Copyright (C) Authors 2007-2012
 *
 * Released under GNU GPL v2+, read the file 'COPYING' for more information.
 */
 
#ifndef INKSCAPE_LPE_KNOT_H
#define INKSCAPE_LPE_KNOT_H
 
 
#include "live_effects/effect.h"
#include "live_effects/lpegroupbbox.h"
#include "live_effects/parameter/array.h"
#include "live_effects/parameter/hidden.h"
#include "live_effects/parameter/parameter.h"
//#include "live_effects/parameter/path.h"
#include "live_effects/parameter/bool.h"
#include <2geom/crossing.h>
 
class SPLPEItem;
 
namespace Inkscape {
namespace LivePathEffect {
 
class KnotHolderEntityCrossingSwitcher;
 
// CrossingPoint, CrossingPoints:
//   "point oriented" storage of crossing data (needed to find crossing nearest to a click, etc...)
//TODO: evaluate how lpeknot-specific that is? Should something like this exist in 2geom?
namespace LPEKnotNS {//just in case...
struct CrossingPoint {
  Geom::Point pt;
  int sign; //+/-1 = positive or neg crossing, 0 = flat.
  unsigned i, j;  //paths components meeting in this point.
  unsigned ni, nj;  //this crossing is the ni-th along i, nj-th along j.
  double ti, tj;  //time along paths.
};
 
class CrossingPoints : public  std::vector<CrossingPoint>{
public:
  CrossingPoints() : std::vector<CrossingPoint>() {}
  CrossingPoints(Geom::CrossingSet const &cs, Geom::PathVector const &path);//for self crossings only!
  CrossingPoints(Geom::PathVector const &paths);
  CrossingPoints(std::vector<double> const &input);
  std::vector<double> to_vector();
  CrossingPoint get(unsigned const i, unsigned const ni);
  void inherit_signs(CrossingPoints const &from_other, int default_value = 1);
};
} 
 
class LPEKnot : public Effect, GroupBBoxEffect {
public:
  LPEKnot(LivePathEffectObject *lpeobject);
  ~LPEKnot() override;
  
  void doBeforeEffect (SPLPEItem const* lpeitem) override;
  Geom::PathVector doEffect_path (Geom::PathVector const & input_path) override;
  
  /* the knotholder entity classes must be declared friends */
  friend class KnotHolderEntityCrossingSwitcher;
  void addKnotHolderEntities(KnotHolder *knotholder, SPItem *item) override;
 
protected:
  void addCanvasIndicators(SPLPEItem const *lpeitem, std::vector<Geom::PathVector> &hp_vec) override;
  Geom::PathVector supplied_path; //for knotholder business
  
private:
  void updateSwitcher();
 
  ScalarParam interruption_width;
  BoolParam prop_to_stroke_width;
  BoolParam both;
  BoolParam inverse_width;
  // "add_stroke_width" and "add_other_stroke_width" parameters are not used since Inkscape 1.0,
  // but changed from bool to hidden parameter to retain backward compatibility and dont show in the UI
  HiddenParam add_stroke_width;
  HiddenParam add_other_stroke_width;
  ScalarParam switcher_size;
  ArrayParam<double> crossing_points_vector;//svg storage of crossing_points
  
  LPEKnotNS::CrossingPoints crossing_points;//topology representation of the knot.
  
  Geom::PathVector gpaths;//the collection of all the paths in the object or group.
  std::vector<double> gstroke_widths;//the collection of all the stroke widths in the object or group.
 
  //UI: please, someone, help me to improve this!!
  unsigned selectedCrossing;//the selected crossing
  Geom::Point switcher;//where to put the "switcher" helper
  
  LPEKnot(const LPEKnot&) = delete;
  LPEKnot& operator=(const LPEKnot&) = delete;
  
};
  
} //namespace LivePathEffect
} //namespace Inkscape
 
#endif