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[inkscape.git] / src / snapper.h
index cad4200ab6e0e237c72af4c8ef9f7e8fa782ed78..91784d3aefa539adf5751e1b58795a3b0f7e6dae 100644 (file)
 
 #include <map>
 #include <list>
-#include "libnr/nr-coord.h"
-#include "libnr/nr-point.h"
-#include "libnr/nr-maybe.h"
+#include <boost/optional.hpp>
+#include <glib.h> // for g_assert
 
 #include "snapped-point.h"
 #include "snapped-line.h"
+#include "snapped-curve.h"
+#include "snap-preferences.h"
+#include "snap-candidate.h"
 
 struct SnappedConstraints {
-    std::list<Inkscape::SnappedPoint> points; 
+    std::list<Inkscape::SnappedPoint> points;
     std::list<Inkscape::SnappedLineSegment> lines;
     std::list<Inkscape::SnappedLine> grid_lines;
     std::list<Inkscape::SnappedLine> guide_lines;
+    std::list<Inkscape::SnappedCurve> curves;
 };
 
-struct SPNamedView;
+class SnapManager;
 struct SPItem;
 
 namespace Inkscape
 {
-
 /// Parent for classes that can snap points to something
 class Snapper
 {
 public:
     Snapper() {}
-    Snapper(SPNamedView const *nv, ::NR::Coord const d);
+    Snapper(SnapManager *sm, ::Geom::Coord const t);
     virtual ~Snapper() {}
 
-    /// Point types to snap.
-    typedef int PointType;
-    static const PointType SNAPPOINT_NODE;
-    static const PointType SNAPPOINT_BBOX;
-    static const PointType SNAPPOINT_GUIDE;
-
-    void setSnapFrom(PointType t, bool s);
-    bool getSnapFrom(PointType t) const;
-    
-    void setSnapperTolerance(NR::Coord t);    
-    NR::Coord getSnapperTolerance() const; //returns the tolerance of the snapper in screen pixels (i.e. independent of zoom)
-    bool getSnapperAlwaysSnap() const; //if true, then the snapper will always snap, regardless of its tolerance
-    
+    virtual Geom::Coord getSnapperTolerance() const = 0; //returns the tolerance of the snapper in screen pixels (i.e. independent of zoom)
+    virtual bool getSnapperAlwaysSnap() const = 0; //if true, then the snapper will always snap, regardless of its tolerance
+
     /**
     *  \return true if this Snapper will snap at least one kind of point.
     */
-    virtual bool ThisSnapperMightSnap() const {return (_snap_enabled && _snap_from != 0);} // will likely be overridden by derived classes
+    virtual bool ThisSnapperMightSnap() const {return _snap_enabled;} // will likely be overridden by derived classes
 
+    // These four methods are only used for grids, for which snapping can be enabled individually
     void setEnabled(bool s);
+    void setSnapVisibleOnly(bool s);
     bool getEnabled() const {return _snap_enabled;}
-
-    void freeSnap(SnappedConstraints &sc,
-                          PointType const &t,
-                          NR::Point const &p,
-                          bool const &first_point,                                             
-                          std::vector<NR::Point> &points_to_snap,                         
-                          SPItem const *it) const;
-                          
-    void freeSnap(SnappedConstraints &sc,
-                          PointType const &t,
-                          NR::Point const &p,
-                          bool const &first_point,                                             
-                          std::vector<NR::Point> &points_to_snap,                         
-                          std::vector<SPItem const *> const &it,
-                          std::vector<NR::Point> *unselected_nodes) const;
-    
-    class ConstraintLine
+    bool getSnapVisibleOnly() const {return _snap_visible_only;}
+
+    virtual void freeSnap(SnappedConstraints &/*sc*/,
+                          Inkscape::SnapCandidatePoint const &/*p*/,
+                          Geom::OptRect const &/*bbox_to_snap*/,
+                          std::vector<SPItem const *> const */*it*/,
+                          std::vector<SnapCandidatePoint> */*unselected_nodes*/) const {};
+
+    // Class for storing the constraint for constrained snapping; can be
+    // - a line (infinite line with origin, running through _point pointing in _direction)
+    // - a direction (infinite line without origin, i.e. only a direction vector, stored in _direction)
+    // - a circle (_point denotes the center, _radius doesn't need an explanation, _direction contains
+    //      the vector from the origin to the original untransformed point);
+    class SnapConstraint
     {
+    private:
+        enum SnapConstraintType {LINE, DIRECTION, CIRCLE, UNDEFINED};
+
     public:
-        ConstraintLine(NR::Point const &d) : _has_point(false), _direction(d) {}
-        ConstraintLine(NR::Point const &p, NR::Point const &d) : _has_point(true), _point(p), _direction(d) {}
+        // Constructs a direction constraint, e.g. horizontal or vertical but without a specified point
+        SnapConstraint(Geom::Point const &d) : _direction(d), _type(DIRECTION) {}
+        // Constructs a linear constraint
+        SnapConstraint(Geom::Point const &p, Geom::Point const &d) : _point(p), _direction(d), _type(LINE) {}
+        SnapConstraint(Geom::Line const &l) : _point(l.origin()), _direction(l.versor()), _type(LINE) {}
+        // Constructs a circular constraint
+        SnapConstraint(Geom::Point const &p, Geom::Point const &d, Geom::Coord const &r) : _point(p), _direction(d), _radius(r), _type(CIRCLE) {}
+        // Undefined, or empty constraint
+        SnapConstraint() : _type(UNDEFINED) {}
+
+        bool hasPoint() const {return _type != DIRECTION && _type != UNDEFINED;}
+
+        Geom::Point getPoint() const {
+            g_assert(_type != DIRECTION && _type != UNDEFINED);
+            return _point;
+        }
 
-        bool hasPoint() const {
-            return _has_point;
+        Geom::Point getDirection() const {
+            return _direction;
         }
 
-        NR::Point getPoint() const {
-            return _point;
+        Geom::Coord getRadius() const {
+            g_assert(_type == CIRCLE);
+            return _radius;
         }
 
-        NR::Point getDirection() const {
-            return _direction;
+        bool isCircular() const { return _type == CIRCLE; }
+        bool isLinear() const { return _type == LINE; }
+        bool isDirection() const { return _type == DIRECTION; }
+        bool isUndefined() const { return _type == UNDEFINED; }
+
+        Geom::Point projection(Geom::Point const &p) const { // returns the projection of p on this constraint
+            if (_type == CIRCLE) {
+                // project on to a circular constraint
+                Geom::Point v_orig = p - _point;
+                Geom::Coord l = Geom::L2(v_orig);
+                if (l > 0) {
+                    return _point + _radius * v_orig/l; // Length of _direction is equal to the radius
+                } else {
+                    // point to be projected is exactly at the center of the circle, so any point on the circle is a projection
+                    return _point + Geom::Point(_radius, 0);
+                }
+            } else if (_type != UNDEFINED){
+                // project on to a linear constraint
+                Geom::Point const p1_on_cl = (_type == LINE) ? _point : p;
+                Geom::Point const p2_on_cl = p1_on_cl + _direction;
+                return Geom::projection(p, Geom::Line(p1_on_cl, p2_on_cl));
+            } else {
+                g_warning("Bug: trying to find the projection onto an undefined constraint");
+                return Geom::Point();
+            }
         }
-        
-    private:
 
-        bool _has_point;
-        NR::Point _point;
-        NR::Point _direction;
+    private:
+        Geom::Point _point;
+        Geom::Point _direction;
+        Geom::Coord _radius;
+        SnapConstraintType _type;
     };
 
-    void constrainedSnap(SnappedConstraints &sc,
-                                 PointType const &t,
-                                 NR::Point const &p,
-                                 bool const &first_point,
-                                 std::vector<NR::Point> &points_to_snap,       
-                                 ConstraintLine const &c,
-                                 SPItem const *it) const;
-
-    void constrainedSnap(SnappedConstraints &sc,
-                                 PointType const &t,
-                                 NR::Point const &p,
-                                 bool const &first_point,
-                                 std::vector<NR::Point> &points_to_snap,                         
-                                 ConstraintLine const &c,
-                                 std::vector<SPItem const *> const &it) const;
-                                 
-protected:
-    SPNamedView const *_named_view;
-    int _snap_from; ///< bitmap of point types that we will snap from
-    bool _snap_enabled; ///< true if this snapper is enabled, otherwise false
-    
-private:
-    NR::Coord _snapper_tolerance;   ///< snap tolerance in desktop coordinates 
-                                    // must be private to enforce the usage of getTolerance(), which retrieves 
-                                    // the tolerance in screen pixels (making it zoom independent)
-
+    virtual void constrainedSnap(SnappedConstraints &/*sc*/,
+                                 Inkscape::SnapCandidatePoint const &/*p*/,
+                                 Geom::OptRect const &/*bbox_to_snap*/,
+                                 SnapConstraint const &/*c*/,
+                                 std::vector<SPItem const *> const */*it*/,
+                                 std::vector<SnapCandidatePoint> */*unselected_nodes*/) const {};
 
-    /**
-     *  Try to snap a point to whatever this snapper is interested in.  Any
-     *  snap that occurs will be to the nearest "interesting" thing (e.g. a
-     *  grid or guide line)
-     *
-     *  \param p Point to snap (desktop coordinates).
-     *  \param it Items that should not be snapped to.
-     *  \return Snapped point.
-     */
-    virtual void _doFreeSnap(SnappedConstraints &sc,
-                                     PointType const &t,
-                                     NR::Point const &p,
-                                     bool const &first_point,                                             
-                                     std::vector<NR::Point> &points_to_snap,
-                                     std::vector<SPItem const *> const &it,
-                                     std::vector<NR::Point> *unselected_nodes) const = 0;
+protected:
+    SnapManager *_snapmanager;
 
-    /**
-     *  Try to snap a point to whatever this snapper is interested in, where
-     *  the snap point is constrained to lie along a specified vector from the
-     *  original point.
-     *
-     *  \param p Point to snap (desktop coordinates).
-     *  \param c Vector to constrain the snap to.
-     *  \param it Items that should not be snapped to.
-     *  \return Snapped point.
-     */    
-    virtual void _doConstrainedSnap(SnappedConstraints &sc,
-                                            PointType const &t,
-                                            NR::Point const &p,
-                                            bool const &first_point,
-                                            std::vector<NR::Point> &points_to_snap,
-                                            ConstraintLine const &c,
-                                            std::vector<SPItem const *> const &it) const = 0;
+    // This is only used for grids, for which snapping can be enabled individually
+    bool _snap_enabled; ///< true if this snapper is enabled, otherwise false
+    bool _snap_visible_only;
 };
 
 }