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snap.h

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#ifndef SEEN_SNAP_H
#define SEEN_SNAP_H

/**
 * \file snap.h
 * \brief SnapManager class.
 *
 * The SnapManager class handles most (if not all) of the interfacing of the snapping mechanisms with the
 * other parts of the code base. It stores the references to the various types of snappers for grid, guides
 * and objects, and it stores most of the snapping preferences. Besides that it provides methods to setup
 * the snapping environment (e.g. keeps a list of the items to ignore when looking for snap target candidates,
 * and toggling of the snap indicator), and it provides many different methods for the snapping itself (free
 * snapping vs. constrained snapping, returning the result by reference or through a return statement, etc.)
 *
 * Authors:
 *   Lauris Kaplinski <lauris@kaplinski.com>
 *   Frank Felfe <innerspace@iname.com>
 *   Carl Hetherington <inkscape@carlh.net>
 *   Diederik van Lierop <mail@diedenrezi.nl>
 *
 * Copyright (C) 2006-2007 Johan Engelen <johan@shouraizou.nl>
 * Copyright (C) 2000-2002 Lauris Kaplinski
 * Copyright (C) 2000-2009 Authors
 *
 * Released under GNU GPL, read the file 'COPYING' for more information
 */

#include <vector>

#include "guide-snapper.h"
#include "object-snapper.h"
#include "snap-preferences.h"

/* Guides */
enum SPGuideDragType { // used both here and in desktop-events.cpp
    SP_DRAG_TRANSLATE,
    SP_DRAG_ROTATE,
    SP_DRAG_MOVE_ORIGIN,
    SP_DRAG_NONE
};

class SPNamedView;

/// Class to coordinate snapping operations

/**
 *  Each SPNamedView has one of these.  It offers methods to snap points to whatever
 *  snappers are defined (e.g. grid, guides etc.).  It also allows callers to snap
 *  points which have undergone some transformation (e.g. translation, scaling etc.)
 */

00052 class SnapManager
{
public:
      enum Transformation {
        TRANSLATION,
        SCALE,
        STRETCH,
        SKEW
    };

      SnapManager(SPNamedView const *v);

    typedef std::list<const Inkscape::Snapper*> SnapperList;

    bool someSnapperMightSnap() const;
    bool gridSnapperMightSnap() const;

    void setup(SPDesktop const *desktop,
                  bool snapindicator = true,
                  SPItem const *item_to_ignore = NULL,
                  std::vector<std::pair<Geom::Point, int> > *unselected_nodes = NULL,
                  SPGuide *guide_to_ignore = NULL);

    void setup(SPDesktop const *desktop,
            bool snapindicator,
            std::vector<SPItem const *> &items_to_ignore,
            std::vector<std::pair<Geom::Point, int> > *unselected_nodes = NULL,
            SPGuide *guide_to_ignore = NULL);

    // freeSnapReturnByRef() is preferred over freeSnap(), because it only returns a
    // point if snapping has occurred (by overwriting p); otherwise p is untouched
    void freeSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
                                          Geom::Point &p,
                                          Inkscape::SnapSourceType const source_type,
                                          bool first_point = true,
                                          Geom::OptRect const &bbox_to_snap = Geom::OptRect()) const;


    Inkscape::SnappedPoint freeSnap(Inkscape::SnapPreferences::PointType point_type,
                                                      Geom::Point const &p,
                                              Inkscape::SnapSourceType const &source_type,
                                    bool first_point = true,
                                    Geom::OptRect const &bbox_to_snap = Geom::OptRect() ) const;

    Geom::Point multipleOfGridPitch(Geom::Point const &t) const;

    // constrainedSnapReturnByRef() is preferred over constrainedSnap(), because it only returns a
    // point, by overwriting p, if snapping has occurred; otherwise p is untouched
    void constrainedSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
                                                      Geom::Point &p,
                                                      Inkscape::SnapSourceType const source_type,
                                                      Inkscape::Snapper::ConstraintLine const &constraint,
                                                      bool first_point = true,
                                                      Geom::OptRect const &bbox_to_snap = Geom::OptRect()) const;

    Inkscape::SnappedPoint constrainedSnap(Inkscape::SnapPreferences::PointType point_type,
                                                               Geom::Point const &p,
                                                               Inkscape::SnapSourceType const &source_type,
                                                               Inkscape::Snapper::ConstraintLine const &constraint,
                                                               bool first_point = true,
                                           Geom::OptRect const &bbox_to_snap = Geom::OptRect()) const;

    void guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const;
    void guideConstrainedSnap(Geom::Point &p, SPGuide const &guideline) const;

    Inkscape::SnappedPoint freeSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
                                               std::vector<std::pair<Geom::Point, int> > const &p,
                                               Geom::Point const &pointer,
                                               Geom::Point const &tr) const;

    Inkscape::SnappedPoint constrainedSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
                                                      std::vector<std::pair<Geom::Point, int> > const &p,
                                                      Geom::Point const &pointer,
                                                      Inkscape::Snapper::ConstraintLine const &constraint,
                                                      Geom::Point const &tr) const;

    Inkscape::SnappedPoint freeSnapScale(Inkscape::SnapPreferences::PointType point_type,
                                         std::vector<std::pair<Geom::Point, int> > const &p,
                                         Geom::Point const &pointer,
                                         Geom::Scale const &s,
                                         Geom::Point const &o) const;

    Inkscape::SnappedPoint constrainedSnapScale(Inkscape::SnapPreferences::PointType point_type,
                                                std::vector<std::pair<Geom::Point, int> > const &p,
                                                Geom::Point const &pointer,
                                                Geom::Scale const &s,
                                                Geom::Point const &o) const;

    Inkscape::SnappedPoint constrainedSnapStretch(Inkscape::SnapPreferences::PointType point_type,
                                                  std::vector<std::pair<Geom::Point, int> > const &p,
                                                  Geom::Point const &pointer,
                                                  Geom::Coord const &s,
                                                  Geom::Point const &o,
                                                  Geom::Dim2 d,
                                                  bool uniform) const;

    Inkscape::SnappedPoint constrainedSnapSkew(Inkscape::SnapPreferences::PointType point_type,
                                               std::vector<std::pair<Geom::Point, int> > const &p,
                                               Geom::Point const &pointer,
                                               Inkscape::Snapper::ConstraintLine const &constraint,
                                               Geom::Point const &s, // s[0] = skew factor, s[1] = scale factor
                                               Geom::Point const &o,
                                               Geom::Dim2 d) const;

00156     Inkscape::GuideSnapper guide;      ///< guide snapper
00157     Inkscape::ObjectSnapper object;    ///< snapper to other objects
    Inkscape::SnapPreferences snapprefs;

    SnapperList getSnappers() const;
    SnapperList getGridSnappers() const;

    SPDesktop const *getDesktop() const {return _desktop;}
    SPNamedView const *getNamedView() const {return _named_view;}
    SPDocument *getDocument() const;
    SPGuide const *getGuideToIgnore() const {return _guide_to_ignore;}

    bool getSnapIndicator() const {return _snapindicator;}

protected:
    SPNamedView const *_named_view;

private:
00174     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
00175     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
00176     SPGuide *_guide_to_ignore; ///< A guide that should not be snapped to, e.g. the guide that is currently being dragged
    SPDesktop const *_desktop;
00178     bool _snapindicator; ///< When true, an indicator will be drawn at the position that was being snapped to
00179     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
    //TODO: Make _unselected_nodes type safe; in the line above int is used for Inkscape::SnapTargetType, but if I remember
    //correctly then in other cases the int is being used for Inkscape::SnapSourceType, or for both. How to make
    //this type safe?

    Inkscape::SnappedPoint _snapTransformed(Inkscape::SnapPreferences::PointType type,
                                            std::vector<std::pair<Geom::Point, int> > const &points,
                                            Geom::Point const &pointer,
                                            bool constrained,
                                            Inkscape::Snapper::ConstraintLine const &constraint,
                                            Transformation transformation_type,
                                            Geom::Point const &transformation,
                                            Geom::Point const &origin,
                                            Geom::Dim2 dim,
                                            bool uniform) const;

    Geom::Point _transformPoint(std::pair<Geom::Point, int> const &p,
                                            Transformation const transformation_type,
                                            Geom::Point const &transformation,
                                            Geom::Point const &origin,
                                            Geom::Dim2 const dim,
                                            bool const uniform) const;

    void _displaySnapsource(Inkscape::SnapPreferences::PointType point_type, std::pair<Geom::Point, int> const &p) const;

    Inkscape::SnappedPoint findBestSnap(Geom::Point const &p, Inkscape::SnapSourceType const source_type, SnappedConstraints &sc, bool constrained, bool noCurves = false) const;
};

#endif /* !SEEN_SNAP_H */

/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
  indent-tabs-mode:nil
  fill-column:99
  End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :

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