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 /* 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<std::pair<Geom::Point, int> > *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<std::pair<Geom::Point, int> > *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                                 long source_num = 0,
  87                                 Geom::OptRect const &bbox_to_snap = Geom::OptRect()) const;
  88
  89
  90     Inkscape::SnappedPoint freeSnap(Inkscape::SnapPreferences::PointType point_type,
  91                                     Geom::Point const &p,
  92                                     Inkscape::SnapSourceType const &source_type,
  93                                     long source_num = 0,
  94                                     Geom::OptRect const &bbox_to_snap = Geom::OptRect() ) const;
  95
  96     Geom::Point multipleOfGridPitch(Geom::Point const &t) const;
  97
  98     // constrainedSnapReturnByRef() is preferred over constrainedSnap(), because it only returns a
  99     // point, by overwriting p, if snapping has occurred; otherwise p is untouched
 100     void constrainedSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
 101                                     Geom::Point &p,
 102                                     Inkscape::SnapSourceType const source_type,
 103                                     Inkscape::Snapper::ConstraintLine const &constraint,
 104                                     long source_num = 0,
 105                                     Geom::OptRect const &bbox_to_snap = Geom::OptRect()) const;
 106
 107     Inkscape::SnappedPoint constrainedSnap(Inkscape::SnapPreferences::PointType point_type,
 108                                            Geom::Point const &p,
 109                                            Inkscape::SnapSourceType const &source_type,
 110                                            Inkscape::Snapper::ConstraintLine const &constraint,
 111                                            long source_num = 0,
 112                                            Geom::OptRect const &bbox_to_snap = Geom::OptRect()) const;
 113
 114     void guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const;
 115     void guideConstrainedSnap(Geom::Point &p, SPGuide const &guideline) const;
 116
 117     Inkscape::SnappedPoint freeSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
 118                                                std::vector<std::pair<Geom::Point, int> > const &p,
 119                                                Geom::Point const &pointer,
 120                                                Geom::Point const &tr) const;
 121
 122     Inkscape::SnappedPoint constrainedSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
 123                                                       std::vector<std::pair<Geom::Point, int> > const &p,
 124                                                       Geom::Point const &pointer,
 125                                                       Inkscape::Snapper::ConstraintLine const &constraint,
 126                                                       Geom::Point const &tr) const;
 127
 128     Inkscape::SnappedPoint freeSnapScale(Inkscape::SnapPreferences::PointType point_type,
 129                                          std::vector<std::pair<Geom::Point, int> > const &p,
 130                                          Geom::Point const &pointer,
 131                                          Geom::Scale const &s,
 132                                          Geom::Point const &o) const;
 133
 134     Inkscape::SnappedPoint constrainedSnapScale(Inkscape::SnapPreferences::PointType point_type,
 135                                                 std::vector<std::pair<Geom::Point, int> > const &p,
 136                                                 Geom::Point const &pointer,
 137                                                 Geom::Scale const &s,
 138                                                 Geom::Point const &o) const;
 139
 140     Inkscape::SnappedPoint constrainedSnapStretch(Inkscape::SnapPreferences::PointType point_type,
 141                                                   std::vector<std::pair<Geom::Point, int> > const &p,
 142                                                   Geom::Point const &pointer,
 143                                                   Geom::Coord const &s,
 144                                                   Geom::Point const &o,
 145                                                   Geom::Dim2 d,
 146                                                   bool uniform) const;
 147
 148     Inkscape::SnappedPoint constrainedSnapSkew(Inkscape::SnapPreferences::PointType point_type,
 149                                                std::vector<std::pair<Geom::Point, int> > const &p,
 150                                                Geom::Point const &pointer,
 151                                                Inkscape::Snapper::ConstraintLine const &constraint,
 152                                                Geom::Point const &s, // s[0] = skew factor, s[1] = scale factor
 153                                                Geom::Point const &o,
 154                                                Geom::Dim2 d) const;
 155
 156     Inkscape::GuideSnapper guide;      ///< guide snapper
 157     Inkscape::ObjectSnapper object;    ///< snapper to other objects
 158     Inkscape::SnapPreferences snapprefs;
 159
 160     SnapperList getSnappers() const;
 161     SnapperList getGridSnappers() const;
 162
 163     SPDesktop const *getDesktop() const {return _desktop;}
 164     SPNamedView const *getNamedView() const {return _named_view;}
 165     SPDocument *getDocument() const;
 166     SPGuide const *getGuideToIgnore() const {return _guide_to_ignore;}
 167
 168     bool getSnapIndicator() const {return _snapindicator;}
 169
 170     Inkscape::SnappedPoint findBestSnap(Geom::Point const &p, Inkscape::SnapSourceType const source_type, SnappedConstraints &sc, bool constrained, bool noCurves = false) const;
 171
 172 protected:
 173     SPNamedView const *_named_view;
 174
 175 private:
 176     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
 177     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
 178     SPGuide *_guide_to_ignore; ///< A guide that should not be snapped to, e.g. the guide that is currently being dragged
 179     SPDesktop const *_desktop;
 180     bool _snapindicator; ///< When true, an indicator will be drawn at the position that was being snapped to
 181     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
 182     //TODO: Make _unselected_nodes type safe; in the line above int is used for Inkscape::SnapTargetType, but if I remember
 183     //correctly then in other cases the int is being used for Inkscape::SnapSourceType, or for both. How to make
 184     //this type safe?
 185
 186     Inkscape::SnappedPoint _snapTransformed(Inkscape::SnapPreferences::PointType type,
 187                                             std::vector<std::pair<Geom::Point, int> > const &points,
 188                                             Geom::Point const &pointer,
 189                                             bool constrained,
 190                                             Inkscape::Snapper::ConstraintLine const &constraint,
 191                                             Transformation transformation_type,
 192                                             Geom::Point const &transformation,
 193                                             Geom::Point const &origin,
 194                                             Geom::Dim2 dim,
 195                                             bool uniform) const;
 196
 197     Geom::Point _transformPoint(std::pair<Geom::Point, int> const &p,
 198                                             Transformation const transformation_type,
 199                                             Geom::Point const &transformation,
 200                                             Geom::Point const &origin,
 201                                             Geom::Dim2 const dim,
 202                                             bool const uniform) const;
 203
 204     void _displaySnapsource(Inkscape::SnapPreferences::PointType point_type, std::pair<Geom::Point, int> const &p) const;
 205 };
 206
 207 #endif /* !SEEN_SNAP_H */
 208
 209 /*
 210   Local Variables:
 211   mode:c++
 212   c-file-style:"stroustrup"
 213   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 214   indent-tabs-mode:nil
 215   fill-column:99
 216   End:
 217 */
 218 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :