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