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) 2000-2010 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 /* Guides */
  35 enum SPGuideDragType { // used both here and in desktop-events.cpp
  36     SP_DRAG_TRANSLATE,
  37     SP_DRAG_ROTATE,
  38     SP_DRAG_MOVE_ORIGIN,
  39     SP_DRAG_NONE
  40 };
  41
  42 class SPNamedView;
  43
  44 /// Class to coordinate snapping operations
  45
  46 /**
  47  *  Each SPNamedView has one of these.  It offers methods to snap points to whatever
  48  *  snappers are defined (e.g. grid, guides etc.).  It also allows callers to snap
  49  *  points which have undergone some transformation (e.g. translation, scaling etc.)
  50  */
  51
  52 class SnapManager
  53 {
  54 public:
  55     enum Transformation {
  56         TRANSLATION,
  57         SCALE,
  58         STRETCH,
  59         SKEW
  60     };
  61
  62     SnapManager(SPNamedView const *v);
  63
  64     typedef std::list<const Inkscape::Snapper*> SnapperList;
  65
  66     bool someSnapperMightSnap() const;
  67     bool gridSnapperMightSnap() const;
  68
  69     void setup(SPDesktop const *desktop,
  70             bool snapindicator = true,
  71             SPItem const *item_to_ignore = NULL,
  72             std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes = NULL,
  73             SPGuide *guide_to_ignore = NULL);
  74
  75     void setup(SPDesktop const *desktop,
  76             bool snapindicator,
  77             std::vector<SPItem const *> &items_to_ignore,
  78             std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes = NULL,
  79             SPGuide *guide_to_ignore = NULL);
  80
  81     // freeSnapReturnByRef() is preferred over freeSnap(), because it only returns a
  82     // point if snapping has occurred (by overwriting p); otherwise p is untouched
  83     void freeSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
  84                                 Geom::Point &p,
  85                                 Inkscape::SnapSourceType const source_type,
  86                                 Geom::OptRect const &bbox_to_snap = Geom::OptRect()) const;
  87
  88     Inkscape::SnappedPoint freeSnap(Inkscape::SnapPreferences::PointType const point_type,
  89                                     Inkscape::SnapCandidatePoint const &p,
  90                                     Geom::OptRect const &bbox_to_snap = Geom::OptRect() ) const;
  91
  92     Geom::Point multipleOfGridPitch(Geom::Point const &t) const;
  93
  94     // constrainedSnapReturnByRef() is preferred over constrainedSnap(), because it only returns a
  95     // point, by overwriting p, if snapping has occurred; otherwise p is untouched
  96     void constrainedSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
  97                                     Geom::Point &p,
  98                                     Inkscape::SnapSourceType const source_type,
  99                                     Inkscape::Snapper::ConstraintLine const &constraint,
 100                                     Geom::OptRect const &bbox_to_snap = Geom::OptRect()) const;
 101
 102     Inkscape::SnappedPoint constrainedSnap(Inkscape::SnapPreferences::PointType const point_type,
 103                                            Inkscape::SnapCandidatePoint const &p,
 104                                            Inkscape::Snapper::ConstraintLine const &constraint,
 105                                            Geom::OptRect const &bbox_to_snap = Geom::OptRect()) const;
 106
 107     void guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const;
 108     void guideConstrainedSnap(Geom::Point &p, SPGuide const &guideline) const;
 109
 110     Inkscape::SnappedPoint freeSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
 111                                                std::vector<Inkscape::SnapCandidatePoint> const &p,
 112                                                Geom::Point const &pointer,
 113                                                Geom::Point const &tr) const;
 114
 115     Inkscape::SnappedPoint constrainedSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
 116                                                       std::vector<Inkscape::SnapCandidatePoint> const &p,
 117                                                       Geom::Point const &pointer,
 118                                                       Inkscape::Snapper::ConstraintLine const &constraint,
 119                                                       Geom::Point const &tr) const;
 120
 121     Inkscape::SnappedPoint freeSnapScale(Inkscape::SnapPreferences::PointType point_type,
 122                                          std::vector<Inkscape::SnapCandidatePoint> const &p,
 123                                          Geom::Point const &pointer,
 124                                          Geom::Scale const &s,
 125                                          Geom::Point const &o) const;
 126
 127     Inkscape::SnappedPoint constrainedSnapScale(Inkscape::SnapPreferences::PointType point_type,
 128                                                 std::vector<Inkscape::SnapCandidatePoint> const &p,
 129                                                 Geom::Point const &pointer,
 130                                                 Geom::Scale const &s,
 131                                                 Geom::Point const &o) const;
 132
 133     Inkscape::SnappedPoint constrainedSnapStretch(Inkscape::SnapPreferences::PointType point_type,
 134                                                   std::vector<Inkscape::SnapCandidatePoint> const &p,
 135                                                   Geom::Point const &pointer,
 136                                                   Geom::Coord const &s,
 137                                                   Geom::Point const &o,
 138                                                   Geom::Dim2 d,
 139                                                   bool uniform) const;
 140
 141     Inkscape::SnappedPoint constrainedSnapSkew(Inkscape::SnapPreferences::PointType point_type,
 142                                                std::vector<Inkscape::SnapCandidatePoint> const &p,
 143                                                Geom::Point const &pointer,
 144                                                Inkscape::Snapper::ConstraintLine const &constraint,
 145                                                Geom::Point const &s, // s[0] = skew factor, s[1] = scale factor
 146                                                Geom::Point const &o,
 147                                                Geom::Dim2 d) const;
 148
 149     Inkscape::GuideSnapper guide;      ///< guide snapper
 150     Inkscape::ObjectSnapper object;    ///< snapper to other objects
 151     Inkscape::SnapPreferences snapprefs;
 152
 153     SnapperList getSnappers() const;
 154     SnapperList getGridSnappers() const;
 155
 156     SPDesktop const *getDesktop() const {return _desktop;}
 157     SPNamedView const *getNamedView() const {return _named_view;}
 158     SPDocument *getDocument() const;
 159     SPGuide const *getGuideToIgnore() const {return _guide_to_ignore;}
 160
 161     bool getSnapIndicator() const {return _snapindicator;}
 162
 163     Inkscape::SnappedPoint findBestSnap(Inkscape::SnapCandidatePoint const &p, SnappedConstraints const &sc, bool constrained, bool noCurves = false) const;
 164
 165 protected:
 166     SPNamedView const *_named_view;
 167
 168 private:
 169     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
 170     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
 171     SPGuide *_guide_to_ignore; ///< A guide that should not be snapped to, e.g. the guide that is currently being dragged
 172     SPDesktop const *_desktop;
 173     bool _snapindicator; ///< When true, an indicator will be drawn at the position that was being snapped to
 174     std::vector<Inkscape::SnapCandidatePoint> *_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
 175     //TODO: Make _unselected_nodes type safe; in the line above int is used for Inkscape::SnapTargetType, but if I remember
 176     //correctly then in other cases the int is being used for Inkscape::SnapSourceType, or for both. How to make
 177     //this type safe?
 178
 179     Inkscape::SnappedPoint _snapTransformed(Inkscape::SnapPreferences::PointType type,
 180                                             std::vector<Inkscape::SnapCandidatePoint> const &points,
 181                                             Geom::Point const &pointer,
 182                                             bool constrained,
 183                                             Inkscape::Snapper::ConstraintLine const &constraint,
 184                                             Transformation transformation_type,
 185                                             Geom::Point const &transformation,
 186                                             Geom::Point const &origin,
 187                                             Geom::Dim2 dim,
 188                                             bool uniform) const;
 189
 190     Geom::Point _transformPoint(Inkscape::SnapCandidatePoint const &p,
 191                                             Transformation const transformation_type,
 192                                             Geom::Point const &transformation,
 193                                             Geom::Point const &origin,
 194                                             Geom::Dim2 const dim,
 195                                             bool const uniform) const;
 196
 197     void _displaySnapsource(Inkscape::SnapPreferences::PointType point_type, Inkscape::SnapCandidatePoint const &p) const;
 198 };
 199
 200 #endif /* !SEEN_SNAP_H */
 201
 202 /*
 203   Local Variables:
 204   mode:c++
 205   c-file-style:"stroustrup"
 206   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 207   indent-tabs-mode:nil
 208   fill-column:99
 209   End:
 210 */
 211 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :