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