src/snap.h

   1 #ifndef SEEN_SNAP_H
   2 #define SEEN_SNAP_H
   3
   4 /**
   5  * \file snap.h
   6  * \brief SnapManager class.
   7  *
   8  * The SnapManager class handles most (if not all) of the interfacing of the snapping mechanisms with the
   9  * other parts of the code base. It stores the references to the various types of snappers for grid, guides
  10  * and objects, and it stores most of the snapping preferences. Besides that it provides methods to setup
  11  * the snapping environment (e.g. keeps a list of the items to ignore when looking for snap target candidates,
  12  * and toggling of the snap indicator), and it provides many different methods for the snapping itself (free
  13  * snapping vs. constrained snapping, returning the result by reference or through a return statement, etc.)
  14  *
  15  * Authors:
  16  *   Lauris Kaplinski <lauris@kaplinski.com>
  17  *   Frank Felfe <innerspace@iname.com>
  18  *   Carl Hetherington <inkscape@carlh.net>
  19  *   Diederik van Lierop <mail@diedenrezi.nl>
  20  *
  21  * Copyright (C) 2006-2007 Johan Engelen <johan@shouraizou.nl>
  22  * Copyright (C) 2000-2002 Lauris Kaplinski
  23  * Copyright (C) 2000-2009 Authors
  24  *
  25  * Released under GNU GPL, read the file 'COPYING' for more information
  26  */
  27
  28 #include <vector>
  29
  30 #include "guide-snapper.h"
  31 #include "object-snapper.h"
  32 #include "snap-preferences.h"
  33
  34 class SPNamedView;
  35
  36 /// Class to coordinate snapping operations
  37
  38 /**
  39  *  Each SPNamedView has one of these.  It offers methods to snap points to whatever
  40  *  snappers are defined (e.g. grid, guides etc.).  It also allows callers to snap
  41  *  points which have undergone some transformation (e.g. translation, scaling etc.)
  42  */
  43
  44 class SnapManager
  45 {
  46 public:
  47         enum Transformation {
  48         TRANSLATION,
  49         SCALE,
  50         STRETCH,
  51         SKEW
  52     };
  53
  54         SnapManager(SPNamedView const *v);
  55
  56     typedef std::list<const Inkscape::Snapper*> SnapperList;
  57
  58     bool someSnapperMightSnap() const;
  59     bool gridSnapperMightSnap() const;
  60
  61     void setup(SPDesktop const *desktop,
  62                         bool snapindicator = true,
  63                         SPItem const *item_to_ignore = NULL,
  64                         std::vector<std::pair<Geom::Point, int> > *unselected_nodes = NULL,
  65                         SPGuide *guide_to_ignore = NULL);
  66
  67     void setup(SPDesktop const *desktop,
  68                 bool snapindicator,
  69                 std::vector<SPItem const *> &items_to_ignore,
  70                 std::vector<std::pair<Geom::Point, int> > *unselected_nodes = NULL,
  71                 SPGuide *guide_to_ignore = NULL);
  72
  73     // freeSnapReturnByRef() is preferred over freeSnap(), because it only returns a
  74     // point if snapping has occurred (by overwriting p); otherwise p is untouched
  75     void freeSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
  76                                                         Geom::Point &p,
  77                                                         Inkscape::SnapSourceType const source_type,
  78                                                         bool first_point = true,
  79                                                         Geom::OptRect const &bbox_to_snap = Geom::OptRect()) const;
  80
  81
  82     Inkscape::SnappedPoint freeSnap(Inkscape::SnapPreferences::PointType point_type,
  83                                                                         Geom::Point const &p,
  84                                                             Inkscape::SnapSourceType const &source_type,
  85                                         bool first_point = true,
  86                                     Geom::OptRect const &bbox_to_snap = Geom::OptRect() ) const;
  87
  88     Geom::Point multipleOfGridPitch(Geom::Point const &t) const;
  89
  90     // constrainedSnapReturnByRef() is preferred over constrainedSnap(), because it only returns a
  91     // point, by overwriting p, if snapping has occurred; otherwise p is untouched
  92     void constrainedSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
  93                                                                         Geom::Point &p,
  94                                                                         Inkscape::SnapSourceType const source_type,
  95                                                                         Inkscape::Snapper::ConstraintLine const &constraint,
  96                                                                         bool first_point = true,
  97                                                                         Geom::OptRect const &bbox_to_snap = Geom::OptRect()) const;
  98
  99     Inkscape::SnappedPoint constrainedSnap(Inkscape::SnapPreferences::PointType point_type,
 100                                                                                    Geom::Point const &p,
 101                                                                                    Inkscape::SnapSourceType const &source_type,
 102                                                                                    Inkscape::Snapper::ConstraintLine const &constraint,
 103                                                                                    bool first_point = true,
 104                                            Geom::OptRect const &bbox_to_snap = Geom::OptRect()) const;
 105
 106     void guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal) const;
 107     void guideConstrainedSnap(Geom::Point &p, SPGuide const &guideline) const;
 108
 109     Inkscape::SnappedPoint freeSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
 110                                                std::vector<std::pair<Geom::Point, int> > const &p,
 111                                                Geom::Point const &pointer,
 112                                                Geom::Point const &tr) const;
 113
 114     Inkscape::SnappedPoint constrainedSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
 115                                                       std::vector<std::pair<Geom::Point, int> > const &p,
 116                                                       Geom::Point const &pointer,
 117                                                       Inkscape::Snapper::ConstraintLine const &constraint,
 118                                                       Geom::Point const &tr) const;
 119
 120     Inkscape::SnappedPoint freeSnapScale(Inkscape::SnapPreferences::PointType point_type,
 121                                          std::vector<std::pair<Geom::Point, int> > const &p,
 122                                          Geom::Point const &pointer,
 123                                          Geom::Scale const &s,
 124                                          Geom::Point const &o) const;
 125
 126     Inkscape::SnappedPoint constrainedSnapScale(Inkscape::SnapPreferences::PointType point_type,
 127                                                 std::vector<std::pair<Geom::Point, int> > const &p,
 128                                                 Geom::Point const &pointer,
 129                                                 Geom::Scale const &s,
 130                                                 Geom::Point const &o) const;
 131
 132     Inkscape::SnappedPoint constrainedSnapStretch(Inkscape::SnapPreferences::PointType point_type,
 133                                                   std::vector<std::pair<Geom::Point, int> > const &p,
 134                                                   Geom::Point const &pointer,
 135                                                   Geom::Coord const &s,
 136                                                   Geom::Point const &o,
 137                                                   Geom::Dim2 d,
 138                                                   bool uniform) const;
 139
 140     Inkscape::SnappedPoint constrainedSnapSkew(Inkscape::SnapPreferences::PointType point_type,
 141                                                std::vector<std::pair<Geom::Point, int> > const &p,
 142                                                Geom::Point const &pointer,
 143                                                Inkscape::Snapper::ConstraintLine const &constraint,
 144                                                Geom::Point const &s, // s[0] = skew factor, s[1] = scale factor
 145                                                Geom::Point const &o,
 146                                                Geom::Dim2 d) const;
 147
 148     Inkscape::GuideSnapper guide;      ///< guide snapper
 149     Inkscape::ObjectSnapper object;    ///< snapper to other objects
 150     Inkscape::SnapPreferences snapprefs;
 151
 152     SnapperList getSnappers() const;
 153     SnapperList getGridSnappers() const;
 154
 155     SPDesktop const *getDesktop() const {return _desktop;}
 156     SPNamedView const *getNamedView() const {return _named_view;}
 157     SPDocument *getDocument() const;
 158     SPGuide const *getGuideToIgnore() const {return _guide_to_ignore;}
 159
 160     bool getSnapIndicator() const {return _snapindicator;}
 161
 162 protected:
 163     SPNamedView const *_named_view;
 164
 165 private:
 166     std::vector<SPItem const *> *_items_to_ignore; ///< Items that should not be snapped to, for example the items that are currently being dragged. Set using the setup() method
 167     SPItem const *_item_to_ignore; ///< Single item that should not be snapped to. If not NULL then this takes precedence over _items_to_ignore. Set using the setup() method
 168     SPGuide *_guide_to_ignore; ///< A guide that should not be snapped to, e.g. the guide that is currently being dragged
 169     SPDesktop const *_desktop;
 170     bool _snapindicator; ///< When true, an indicator will be drawn at the position that was being snapped to
 171     std::vector<std::pair<Geom::Point, int> > *_unselected_nodes; ///< Nodes of the path that is currently being edited and which have not been selected and which will therefore be stationary. Only these nodes will be considered for snapping to. Of each unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored
 172     //TODO: Make _unselected_nodes type safe; in the line above int is used for Inkscape::SnapTargetType, but if I remember
 173     //correctly then in other cases the int is being used for Inkscape::SnapSourceType, or for both. How to make
 174     //this type safe?
 175
 176     Inkscape::SnappedPoint _snapTransformed(Inkscape::SnapPreferences::PointType type,
 177                                             std::vector<std::pair<Geom::Point, int> > const &points,
 178                                             Geom::Point const &pointer,
 179                                             bool constrained,
 180                                             Inkscape::Snapper::ConstraintLine const &constraint,
 181                                             Transformation transformation_type,
 182                                             Geom::Point const &transformation,
 183                                             Geom::Point const &origin,
 184                                             Geom::Dim2 dim,
 185                                             bool uniform) const;
 186
 187     Geom::Point _transformPoint(std::pair<Geom::Point, int> const &p,
 188                                             Transformation const transformation_type,
 189                                             Geom::Point const &transformation,
 190                                             Geom::Point const &origin,
 191                                             Geom::Dim2 const dim,
 192                                             bool const uniform) const;
 193
 194     void _displaySnapsource(Inkscape::SnapPreferences::PointType point_type, std::pair<Geom::Point, int> const &p) const;
 195
 196     Inkscape::SnappedPoint findBestSnap(Geom::Point const &p, Inkscape::SnapSourceType const source_type, SnappedConstraints &sc, bool constrained) const;
 197 };
 198
 199 #endif /* !SEEN_SNAP_H */
 200
 201 /*
 202   Local Variables:
 203   mode:c++
 204   c-file-style:"stroustrup"
 205   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 206   indent-tabs-mode:nil
 207   fill-column:99
 208   End:
 209 */
 210 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :