src/snapper.h

   1 #ifndef SEEN_SNAPPER_H
   2 #define SEEN_SNAPPER_H
   3
   4 /**
   5  *    \file src/snapper.h
   6  *    \brief Snapper class.
   7  *
   8  *    Authors:
   9  *      Carl Hetherington <inkscape@carlh.net>
  10  *      Diederik van Lierop <mail@diedenrezi.nl>
  11  *
  12  *    Released under GNU GPL, read the file 'COPYING' for more information.
  13  */
  14
  15 #include <map>
  16 #include <list>
  17 #include "libnr/nr-coord.h"
  18 #include "libnr/nr-point.h"
  19 #include "libnr/nr-maybe.h"
  20
  21 #include "snapped-point.h"
  22 #include "snapped-line.h"
  23
  24 struct SnappedConstraints {
  25     std::list<Inkscape::SnappedPoint> points;
  26     std::list<Inkscape::SnappedLineSegment> lines;
  27     std::list<Inkscape::SnappedLine> grid_lines;
  28     std::list<Inkscape::SnappedLine> guide_lines;
  29 };
  30
  31 struct SPNamedView;
  32 struct SPItem;
  33
  34 namespace Inkscape
  35 {
  36
  37 /// Parent for classes that can snap points to something
  38 class Snapper
  39 {
  40 public:
  41     Snapper() {}
  42     Snapper(SPNamedView const *nv, ::NR::Coord const d);
  43     virtual ~Snapper() {}
  44
  45     /// Point types to snap.
  46     typedef int PointType;
  47     static const PointType SNAPPOINT_NODE;
  48     static const PointType SNAPPOINT_BBOX;
  49     static const PointType SNAPPOINT_GUIDE;
  50
  51     void setSnapFrom(PointType t, bool s);
  52     bool getSnapFrom(PointType t) const;
  53
  54     void setSnapperTolerance(NR::Coord t);
  55     NR::Coord getSnapperTolerance() const; //returns the tolerance of the snapper in screen pixels (i.e. independent of zoom)
  56     bool getSnapperAlwaysSnap() const; //if true, then the snapper will always snap, regardless of its tolerance
  57
  58     /**
  59     *  \return true if this Snapper will snap at least one kind of point.
  60     */
  61     virtual bool ThisSnapperMightSnap() const {return (_snap_enabled && _snap_from != 0);} // will likely be overridden by derived classes
  62
  63     void setEnabled(bool s);
  64     bool getEnabled() const {return _snap_enabled;}
  65
  66     void freeSnap(SnappedConstraints &sc,
  67                           PointType const &t,
  68                           NR::Point const &p,
  69                           bool const &first_point,
  70                           std::vector<NR::Point> &points_to_snap,
  71                           SPItem const *it) const;
  72
  73     void freeSnap(SnappedConstraints &sc,
  74                           PointType const &t,
  75                           NR::Point const &p,
  76                           bool const &first_point,
  77                           std::vector<NR::Point> &points_to_snap,
  78                           std::vector<SPItem const *> const &it,
  79                           std::vector<NR::Point> *unselected_nodes) const;
  80
  81     class ConstraintLine
  82     {
  83     public:
  84         ConstraintLine(NR::Point const &d) : _has_point(false), _direction(d) {}
  85         ConstraintLine(NR::Point const &p, NR::Point const &d) : _has_point(true), _point(p), _direction(d) {}
  86
  87         bool hasPoint() const {
  88             return _has_point;
  89         }
  90
  91         NR::Point getPoint() const {
  92             return _point;
  93         }
  94
  95         NR::Point getDirection() const {
  96             return _direction;
  97         }
  98
  99     private:
 100
 101         bool _has_point;
 102         NR::Point _point;
 103         NR::Point _direction;
 104     };
 105
 106     void constrainedSnap(SnappedConstraints &sc,
 107                                  PointType const &t,
 108                                  NR::Point const &p,
 109                                  bool const &first_point,
 110                                  std::vector<NR::Point> &points_to_snap,
 111                                  ConstraintLine const &c,
 112                                  SPItem const *it) const;
 113
 114     void constrainedSnap(SnappedConstraints &sc,
 115                                  PointType const &t,
 116                                  NR::Point const &p,
 117                                  bool const &first_point,
 118                                  std::vector<NR::Point> &points_to_snap,
 119                                  ConstraintLine const &c,
 120                                  std::vector<SPItem const *> const &it) const;
 121
 122 protected:
 123     SPNamedView const *_named_view;
 124     int _snap_from; ///< bitmap of point types that we will snap from
 125     bool _snap_enabled; ///< true if this snapper is enabled, otherwise false
 126
 127 private:
 128     NR::Coord _snapper_tolerance;   ///< snap tolerance in desktop coordinates
 129                                     // must be private to enforce the usage of getTolerance(), which retrieves
 130                                     // the tolerance in screen pixels (making it zoom independent)
 131
 132
 133     /**
 134      *  Try to snap a point to whatever this snapper is interested in.  Any
 135      *  snap that occurs will be to the nearest "interesting" thing (e.g. a
 136      *  grid or guide line)
 137      *
 138      *  \param p Point to snap (desktop coordinates).
 139      *  \param it Items that should not be snapped to.
 140      *  \return Snapped point.
 141      */
 142     virtual void _doFreeSnap(SnappedConstraints &sc,
 143                                      PointType const &t,
 144                                      NR::Point const &p,
 145                                      bool const &first_point,
 146                                      std::vector<NR::Point> &points_to_snap,
 147                                      std::vector<SPItem const *> const &it,
 148                                      std::vector<NR::Point> *unselected_nodes) const = 0;
 149
 150     /**
 151      *  Try to snap a point to whatever this snapper is interested in, where
 152      *  the snap point is constrained to lie along a specified vector from the
 153      *  original point.
 154      *
 155      *  \param p Point to snap (desktop coordinates).
 156      *  \param c Vector to constrain the snap to.
 157      *  \param it Items that should not be snapped to.
 158      *  \return Snapped point.
 159      */
 160     virtual void _doConstrainedSnap(SnappedConstraints &sc,
 161                                             PointType const &t,
 162                                             NR::Point const &p,
 163                                             bool const &first_point,
 164                                             std::vector<NR::Point> &points_to_snap,
 165                                             ConstraintLine const &c,
 166                                             std::vector<SPItem const *> const &it) const = 0;
 167 };
 168
 169 }
 170
 171 #endif /* !SEEN_SNAPPER_H */
 172
 173 /*
 174   Local Variables:
 175   mode:c++
 176   c-file-style:"stroustrup"
 177   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 178   indent-tabs-mode:nil
 179   fill-column:99
 180   End:
 181 */
 182 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :