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[inkscape.git] / src / snap.cpp
index 592c65fec3280b94708a70864d11ac28df4cb91b..a170046c23c4a70232e82819e25f3d03d6e4affc 100644 (file)
 
 /**
  * \file snap.cpp
- *
- * \brief Various snapping methods
+ * \brief SnapManager class.
  *
  * Authors:
  *   Lauris Kaplinski <lauris@kaplinski.com>
  *   Frank Felfe <innerspace@iname.com>
+ *   Nathan Hurst <njh@njhurst.com>
  *   Carl Hetherington <inkscape@carlh.net>
+ *   Diederik van Lierop <mail@diedenrezi.nl>
  *
- * Copyright (C) 1999-2002 Authors
+ * Copyright (C) 2006-2007 Johan Engelen <johan@shouraizou.nl>
+ * Copyrigth (C) 2004      Nathan Hurst
+ * Copyright (C) 1999-2009 Authors
  *
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
+#include <utility>
+
 #include "sp-namedview.h"
 #include "snap.h"
+#include "snapped-line.h"
+#include "snapped-curve.h"
+
 #include <libnr/nr-point-fns.h>
 #include <libnr/nr-scale-ops.h>
 #include <libnr/nr-values.h>
 
-SnapManager::SnapperList SnapManager::getSnappers() const
+#include "display/canvas-grid.h"
+#include "display/snap-indicator.h"
+
+#include "inkscape.h"
+#include "desktop.h"
+#include "sp-guide.h"
+#include "preferences.h"
+using std::vector;
+
+/**
+ *  Construct a SnapManager for a SPNamedView.
+ *
+ *  \param v `Owning' SPNamedView.
+ */
+
+SnapManager::SnapManager(SPNamedView const *v) :
+    guide(this, 0),
+    object(this, 0),
+    snapprefs(),
+    _named_view(v)
+{
+}
+
+/**
+ *  \return List of snappers that we use.
+ */
+SnapManager::SnapperList
+SnapManager::getSnappers() const
 {
     SnapManager::SnapperList s;
-    s.push_back(&grid);
     s.push_back(&guide);
     s.push_back(&object);
+
+    SnapManager::SnapperList gs = getGridSnappers();
+    s.splice(s.begin(), gs);
+
+    return s;
+}
+
+/**
+ *  \return List of gridsnappers that we use.
+ */
+SnapManager::SnapperList
+SnapManager::getGridSnappers() const
+{
+    SnapperList s;
+
+    //FIXME: this code should actually do this: add new grid snappers that are active for this desktop. now it just adds all gridsnappers
+    if (_desktop && _desktop->gridsEnabled() && snapprefs.getSnapToGrids()) {
+        for ( GSList const *l = _named_view->grids; l != NULL; l = l->next) {
+            Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
+            s.push_back(grid->snapper);
+        }
+    }
+
     return s;
 }
 
 /**
  * \return true if one of the snappers will try to snap something.
  */
-bool SnapManager::willSnapSomething() const
+
+bool SnapManager::someSnapperMightSnap() const
 {
+    if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) {
+        return false;
+    }
+
     SnapperList const s = getSnappers();
     SnapperList::const_iterator i = s.begin();
-    while (i != s.end() && (*i)->willSnapSomething() == false) {
+    while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
         i++;
     }
 
     return (i != s.end());
 }
 
+/**
+ * \return true if one of the snappers will try to snap something.
+ */
 
-/* FIXME: lots of cut-and-paste here.  This needs some
-** functor voodoo to cut it all down a bit.
-*/
+bool SnapManager::gridSnapperMightSnap() const
+{
+    if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) {
+        return false;
+    }
+
+    SnapperList const s = getGridSnappers();
+    SnapperList::const_iterator i = s.begin();
+    while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
+        i++;
+    }
 
-Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::Snapper::PointType t,
-                                             NR::Point const &p,
-                                             SPItem const *it) const
+    return (i != s.end());
+}
+
+/**
+ *  Try to snap a point to any of the specified snappers.
+ *
+ *  \param point_type Type of point.
+ *  \param p Point.
+ *  \param first_point If true then this point is the first one from a whole bunch of points
+ *  \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
+ *  \param snappers List of snappers to try to snap to
+ *  \return Snapped point.
+ */
 
+void SnapManager::freeSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
+                                                                                        Geom::Point &p,
+                                                                                        Inkscape::SnapSourceType const source_type,
+                                                                                        bool first_point,
+                                             Geom::OptRect const &bbox_to_snap) const
 {
-    std::list<SPItem const *> lit;
-    lit.push_back(it);
-    return freeSnap(t, p, lit);
+    Inkscape::SnappedPoint const s = freeSnap(point_type, p, source_type, first_point, bbox_to_snap);
+    s.getPoint(p);
 }
 
 
-Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::Snapper::PointType t,
-                                             NR::Point const &p,
-                                             std::list<SPItem const *> const &it) const
+/**
+ *  Try to snap a point to any of the specified snappers.
+ *
+ *  \param point_type Type of point.
+ *  \param p Point.
+ *  \param first_point If true then this point is the first one from a whole bunch of points
+ *  \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
+ *  \param snappers List of snappers to try to snap to
+ *  \return Snapped point.
+ */
+
+Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::SnapPreferences::PointType point_type,
+                                                                                        Geom::Point const &p,
+                                                                                        Inkscape::SnapSourceType const &source_type,
+                                                                                        bool first_point,
+                                             Geom::OptRect const &bbox_to_snap) const
 {
-    Inkscape::SnappedPoint r(p, NR_HUGE);
+       if (_desktop->canvas->context_snap_delay_active == false) {
+               g_warning("context_snap_delay_active has not been set to true by the current context. Please report this!");
+               // When the context goes into dragging-mode, then Inkscape should call this: sp_canvas_set_snap_delay_active(desktop->canvas, true);
+       }
 
+       if (!someSnapperMightSnap()) {
+        return Inkscape::SnappedPoint(p, source_type, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
+    }
+
+    std::vector<SPItem const *> *items_to_ignore;
+    if (_item_to_ignore) { // If we have only a single item to ignore
+        // then build a list containing this single item;
+        // This single-item list will prevail over any other _items_to_ignore list, should that exist
+        items_to_ignore = new std::vector<SPItem const *>;
+        items_to_ignore->push_back(_item_to_ignore);
+    } else {
+        items_to_ignore = _items_to_ignore;
+    }
+
+    SnappedConstraints sc;
     SnapperList const snappers = getSnappers();
+
     for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
-        Inkscape::SnappedPoint const s = (*i)->freeSnap(t, p, it);
-        if (s.getDistance() < r.getDistance()) {
-            r = s;
+        (*i)->freeSnap(sc, point_type, p, source_type, first_point, bbox_to_snap, items_to_ignore, _unselected_nodes);
+    }
+
+    if (_item_to_ignore) {
+        delete items_to_ignore;
+    }
+
+    return findBestSnap(p, source_type, sc, false);
+}
+
+// When pasting, we would like to snap to the grid. Problem is that we don't know which nodes were
+// aligned to the grid at the time of copying, so we don't know which nodes to snap. If we'd snap an
+// unaligned node to the grid, previously aligned nodes would become unaligned. That's undesirable.
+// Instead we will make sure that the offset between the source and the copy is a multiple of the grid
+// pitch. If the source was aligned, then the copy will therefore also be aligned
+// PS: Whether we really find a multiple also depends on the snapping range!
+Geom::Point SnapManager::multipleOfGridPitch(Geom::Point const &t) const
+{
+    if (!snapprefs.getSnapEnabledGlobally()) // No need to check for snapprefs.getSnapPostponedGlobally() here
+        return t;
+
+    //FIXME: this code should actually do this: add new grid snappers that are active for this desktop. now it just adds all gridsnappers
+
+    if (_desktop && _desktop->gridsEnabled()) {
+        bool success = false;
+        Geom::Point nearest_multiple;
+        Geom::Coord nearest_distance = NR_HUGE;
+
+        // It will snap to the grid for which we find the closest snap. This might be a different
+        // grid than to which the objects were initially aligned. I don't see an easy way to fix
+        // this, so when using multiple grids one can get unexpected results
+
+        // Cannot use getGridSnappers() because we need both the grids AND their snappers
+        // Therefore we iterate through all grids manually
+        for (GSList const *l = _named_view->grids; l != NULL; l = l->next) {
+            Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
+            const Inkscape::Snapper* snapper = grid->snapper;
+            if (snapper && snapper->ThisSnapperMightSnap()) {
+                // To find the nearest multiple of the grid pitch for a given translation t, we
+                // will use the grid snapper. Simply snapping the value t to the grid will do, but
+                // only if the origin of the grid is at (0,0). If it's not then compensate for this
+                // in the translation t
+                Geom::Point const t_offset = t + grid->origin;
+                SnappedConstraints sc;
+                // Only the first three parameters are being used for grid snappers
+                snapper->freeSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_NODE, t_offset, Inkscape::SNAPSOURCE_UNDEFINED, TRUE, Geom::OptRect(), NULL, NULL);
+                // Find the best snap for this grid, including intersections of the grid-lines
+                Inkscape::SnappedPoint s = findBestSnap(t_offset, Inkscape::SNAPSOURCE_UNDEFINED, sc, false);
+                if (s.getSnapped() && (s.getSnapDistance() < nearest_distance)) {
+                    // use getSnapDistance() instead of getWeightedDistance() here because the pointer's position
+                    // doesn't tell us anything about which node to snap
+                    success = true;
+                    nearest_multiple = s.getPoint() - to_2geom(grid->origin);
+                    nearest_distance = s.getSnapDistance();
+                }
+            }
         }
+
+        if (success)
+            return nearest_multiple;
     }
 
-    return r;
+    return t;
 }
 
+/**
+ *  Try to snap a point to any interested snappers.  A snap will only occur along
+ *  a line described by a Inkscape::Snapper::ConstraintLine.
+ *
+ *  \param point_type Type of point.
+ *  \param p Point.
+ *  \param first_point If true then this point is the first one from a whole bunch of points
+ *  \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
+ *  \param constraint Constraint line.
+ *  \return Snapped point.
+ */
 
-Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::Snapper::PointType t,
-                                                    NR::Point const &p,
-                                                    NR::Point const &c,
-                                                    SPItem const *it) const
+void SnapManager::constrainedSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
+                                                                                                       Geom::Point &p,
+                                                                                                       Inkscape::SnapSourceType const source_type,
+                                                    Inkscape::Snapper::ConstraintLine const &constraint,
+                                                    bool first_point,
+                                                    Geom::OptRect const &bbox_to_snap) const
 {
-    std::list<SPItem const *> lit;
-    lit.push_back(it);
-    return constrainedSnap(t, p, c, lit);
+    Inkscape::SnappedPoint const s = constrainedSnap(point_type, p, source_type, constraint, first_point, bbox_to_snap);
+    s.getPoint(p);
 }
 
 
-Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::Snapper::PointType t,
-                                                    NR::Point const &p,
-                                                    NR::Point const &c,
-                                                    std::list<SPItem const *> const &it) const
+/**
+ *  Try to snap a point to any interested snappers.  A snap will only occur along
+ *  a line described by a Inkscape::Snapper::ConstraintLine.
+ *
+ *  \param point_type Type of point.
+ *  \param p Point.
+ *  \param first_point If true then this point is the first one from a whole bunch of points
+ *  \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
+ *  \param constraint Constraint line.
+ *  \return Snapped point.
+ */
+
+Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::SnapPreferences::PointType point_type,
+                                                                                                       Geom::Point const &p,
+                                                                                                       Inkscape::SnapSourceType const &source_type,
+                                                    Inkscape::Snapper::ConstraintLine const &constraint,
+                                                    bool first_point,
+                                                    Geom::OptRect const &bbox_to_snap) const
 {
-    Inkscape::SnappedPoint r(p, NR_HUGE);
+       if (_desktop->canvas->context_snap_delay_active == false) {
+               g_warning("context_snap_delay_active has not been set to true by the current context. Please report this!");
+               // When the context goes into dragging-mode, then Inkscape should call this: sp_canvas_set_snap_delay_active(desktop->canvas, true);
+       }
 
+       if (!someSnapperMightSnap()) {
+        return Inkscape::SnappedPoint(p, source_type, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
+    }
+
+    std::vector<SPItem const *> *items_to_ignore;
+    if (_item_to_ignore) { // If we have only a single item to ignore
+        // then build a list containing this single item;
+        // This single-item list will prevail over any other _items_to_ignore list, should that exist
+        items_to_ignore = new std::vector<SPItem const *>;
+        items_to_ignore->push_back(_item_to_ignore);
+    } else {
+        items_to_ignore = _items_to_ignore;
+    }
+
+    SnappedConstraints sc;
     SnapperList const snappers = getSnappers();
     for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
-        Inkscape::SnappedPoint const s = (*i)->constrainedSnap(t, p, c, it);
-        if (s.getDistance() < r.getDistance()) {
-            r = s;
-        }
+        (*i)->constrainedSnap(sc, point_type, p, source_type, first_point, bbox_to_snap, constraint, items_to_ignore);
     }
 
-    return r;
-}
+    if (_item_to_ignore) {
+        delete items_to_ignore;
+    }
 
+    return findBestSnap(p, source_type, sc, true);
+}
 
-std::pair<NR::Point, bool> SnapManager::freeSnapTranslation(Inkscape::Snapper::PointType t,
-                                                            std::vector<NR::Point> const &p,
-                                                            std::list<SPItem const *> const &it,
-                                                            NR::Point const &tr) const
+void SnapManager::guideSnap(Geom::Point &p, Geom::Point const &guide_normal) const
 {
-    if (willSnapSomething() == false) {
-        return std::make_pair(tr, false);
-    }
+    // This method is used to snap a guide to nodes, while dragging the guide around
 
-    NR::Point best_translation = tr;
-    NR::Coord best_distance = NR_HUGE;
+       if (_desktop->canvas->context_snap_delay_active == false) {
+               g_warning("context_snap_delay_active has not been set to true by the current context. Please report this!");
+               // When the context goes into dragging-mode, then Inkscape should call this: sp_canvas_set_snap_delay_active(desktop->canvas, true);
+       }
 
-    for (std::vector<NR::Point>::const_iterator i = p.begin(); i != p.end(); i++) {
-        /* Translated version of this point */
-        NR::Point const q = *i + tr;
-        /* Snap it */
-        Inkscape::SnappedPoint s = freeSnap(t, q, it);
-        if (s.getDistance() < NR_HUGE) {
-            /* Resulting translation */
-            NR::Point const r = s.getPoint() - *i;
-            NR::Coord const d = NR::L2(r);
-            if (d < best_distance) {
-                best_distance = d;
-                best_translation = r;
-            }
-        }
+    if ( !(object.GuidesMightSnap() && snapprefs.getSnapEnabledGlobally()) || snapprefs.getSnapPostponedGlobally() ) {
+        return;
     }
 
-    return std::make_pair(best_translation, best_distance < NR_HUGE);
+    SnappedConstraints sc;
+    object.guideSnap(sc, p, guide_normal);
+
+    Inkscape::SnappedPoint const s = findBestSnap(p, Inkscape::SNAPSOURCE_GUIDE, sc, false);
+    s.getPoint(p);
 }
 
 
+/**
+ *  Main internal snapping method, which is called by the other, friendlier, public
+ *  methods.  It's a bit hairy as it has lots of parameters, but it saves on a lot
+ *  of duplicated code.
+ *
+ *  \param type Type of points being snapped.
+ *  \param points List of points to snap (i.e. untransformed).
+ *  \param pointer Location of the mouse pointer, at the time when dragging started (i.e. "untransformed")
+ *  \param constrained true if the snap is constrained.
+ *  \param constraint Constraint line to use, if `constrained' is true, otherwise undefined.
+ *  \param transformation_type Type of transformation to apply to points before trying to snap them.
+ *  \param transformation Description of the transformation; details depend on the type.
+ *  \param origin Origin of the transformation, if applicable.
+ *  \param dim Dimension of the transformation, if applicable.
+ *  \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
+ */
 
-std::pair<NR::Point, bool> SnapManager::constrainedSnapTranslation(Inkscape::Snapper::PointType t,
-                                                                   std::vector<NR::Point> const &p,
-                                                                   NR::Point const &c,
-                                                                   std::list<SPItem const *> const &it,
-                                                                   NR::Point const &tr) const
+Inkscape::SnappedPoint SnapManager::_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
 {
-    if (willSnapSomething() == false) {
-        return std::make_pair(tr, false);
+    /* We have a list of points, which we are proposing to transform in some way.  We need to see
+    ** if any of these points, when transformed, snap to anything.  If they do, we return the
+    ** appropriate transformation with `true'; otherwise we return the original scale with `false'.
+    */
+
+    /* Quick check to see if we have any snappers that are enabled
+    ** Also used to globally disable all snapping
+    */
+    if (someSnapperMightSnap() == false) {
+        return Inkscape::SnappedPoint();
     }
 
-    NR::Point best_translation = tr;
-    NR::Coord best_distance = NR_HUGE;
+    std::vector<std::pair<Geom::Point, int> > transformed_points;
+    Geom::Rect bbox;
 
-    for (std::vector<NR::Point>::const_iterator i = p.begin(); i != p.end(); i++) {
-        /* Translated version of this point */
-        NR::Point const q = *i + tr;
-        /* Snap it */
-        Inkscape::SnappedPoint s = constrainedSnap(t, q, c, it);
-        if (s.getDistance() < NR_HUGE) {
-            /* Resulting translation */
-            NR::Point const r = s.getPoint() - *i;
-            NR::Coord const d = NR::L2(r);
-            if (d < best_distance) {
-                best_distance = d;
-                best_translation = r;
-            }
+    for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = points.begin(); i != points.end(); i++) {
+
+        /* Work out the transformed version of this point */
+        Geom::Point transformed = _transformPoint(*i, transformation_type, transformation, origin, dim, uniform);
+
+        // add the current transformed point to the box hulling all transformed points
+        if (i == points.begin()) {
+            bbox = Geom::Rect(transformed, transformed);
+        } else {
+            bbox.expandTo(transformed);
         }
+
+        transformed_points.push_back(std::make_pair(transformed, (*i).second));
     }
 
-    return std::make_pair(best_translation, best_distance < NR_HUGE);
-}
+    /* The current best transformation */
+    Geom::Point best_transformation = transformation;
 
+    /* The current best metric for the best transformation; lower is better, NR_HUGE
+    ** means that we haven't snapped anything.
+    */
+    Geom::Point best_scale_metric(NR_HUGE, NR_HUGE);
+    Inkscape::SnappedPoint best_snapped_point;
+    g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point
+    g_assert(best_snapped_point.getAtIntersection() == false);
+
+    std::vector<std::pair<Geom::Point, int> >::const_iterator j = transformed_points.begin();
+
+    // std::cout << std::endl;
+    for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = points.begin(); i != points.end(); i++) {
+
+        /* Snap it */
+        Inkscape::SnappedPoint snapped_point;
+        Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint;
+        Geom::Point const b = ((*i).first - origin); // vector to original point
+
+        if (constrained) {
+            if ((transformation_type == SCALE || transformation_type == STRETCH) && uniform) {
+                // When uniformly scaling, each point will have its own unique constraint line,
+                // running from the scaling origin to the original untransformed point. We will
+                // calculate that line here
+                dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, b);
+            } else if (transformation_type == STRETCH) { // when non-uniform stretching {
+                dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i).first, component_vectors[dim]);
+            } else if (transformation_type == TRANSLATION) {
+                // When doing a constrained translation, all points will move in the same direction, i.e.
+                // either horizontally or vertically. The lines along which they move are therefore all
+                // parallel, but might not be colinear. Therefore we will have to set the point through
+                // which the constraint-line runs here, for each point individually.
+                dedicated_constraint.setPoint((*i).first);
+            } // else: leave the original constraint, e.g. for skewing
+            if (transformation_type == SCALE && !uniform) {
+                g_warning("Non-uniform constrained scaling is not supported!");
+            }
+            snapped_point = constrainedSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), dedicated_constraint, i == points.begin(), bbox);
+        } else {
+            bool const c1 = fabs(b[Geom::X]) < 1e-6;
+            bool const c2 = fabs(b[Geom::Y]) < 1e-6;
+            if (transformation_type == SCALE && (c1 || c2) && !(c1 && c2)) {
+                // When scaling, a point aligned either horizontally or vertically with the origin can only
+                // move in that specific direction; therefore it should only snap in that direction, otherwise
+                // we will get snapped points with an invalid transformation
+                dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, component_vectors[c1]);
+                snapped_point = constrainedSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), dedicated_constraint, i == points.begin(), bbox);
+            } else {
+                snapped_point = freeSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), i == points.begin(), bbox);
+            }
+        }
+        // std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl;
+        snapped_point.setPointerDistance(Geom::L2(pointer - (*i).first));
+
+        Geom::Point result;
+        Geom::Point scale_metric(NR_HUGE, NR_HUGE);
+
+        if (snapped_point.getSnapped()) {
+            /* We snapped.  Find the transformation that describes where the snapped point has
+            ** ended up, and also the metric for this transformation.
+            */
+            Geom::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point
+            //Geom::Point const b = (*i - origin); // vector to original point
+
+            switch (transformation_type) {
+                case TRANSLATION:
+                    result = snapped_point.getPoint() - (*i).first;
+                    /* Consider the case in which a box is almost aligned with a grid in both
+                     * horizontal and vertical directions. The distance to the intersection of
+                     * the grid lines will always be larger then the distance to a single grid
+                     * line. If we prefer snapping to an intersection instead of to a single
+                     * grid line, then we cannot use "metric = Geom::L2(result)". Therefore the
+                     * snapped distance will be used as a metric. Please note that the snapped
+                     * distance is defined as the distance to the nearest line of the intersection,
+                     * and not to the intersection itself!
+                     */
+                    // Only for translations, the relevant metric will be the real snapped distance,
+                    // so we don't have to do anything special here
+                    break;
+                case SCALE:
+                {
+                    result = Geom::Point(NR_HUGE, NR_HUGE);
+                    // If this point *i is horizontally or vertically aligned with
+                    // the origin of the scaling, then it will scale purely in X or Y
+                    // We can therefore only calculate the scaling in this direction
+                    // and the scaling factor for the other direction should remain
+                    // untouched (unless scaling is uniform ofcourse)
+                    for (int index = 0; index < 2; index++) {
+                        if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
+                            if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
+                                result[index] = a[index] / b[index]; // then calculate it!
+                            }
+                            // we might leave result[1-index] = NR_HUGE
+                            // if scaling didn't occur in the other direction
+                        }
+                    }
+                    // Compare the resulting scaling with the desired scaling
+                    scale_metric = result - transformation; // One or both of its components might be NR_HUGE
+                    break;
+                }
+                case STRETCH:
+                    result = Geom::Point(NR_HUGE, NR_HUGE);
+                    if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
+                        result[dim] = a[dim] / b[dim];
+                        result[1-dim] = uniform ? result[dim] : 1;
+                    } else { // STRETCHING might occur for this point, but only when the stretching is uniform
+                        if (uniform && fabs(b[1-dim]) > 1e-6) {
+                           result[1-dim] = a[1-dim] / b[1-dim];
+                           result[dim] = result[1-dim];
+                        }
+                    }
+                    // Store the metric for this transformation as a virtual distance
+                    snapped_point.setSnapDistance(std::abs(result[dim] - transformation[dim]));
+                    snapped_point.setSecondSnapDistance(NR_HUGE);
+                    break;
+                case SKEW:
+                    result[0] = (snapped_point.getPoint()[dim] - ((*i).first)[dim]) / (((*i).first)[1 - dim] - origin[1 - dim]); // skew factor
+                    result[1] = transformation[1]; // scale factor
+                    // Store the metric for this transformation as a virtual distance
+                    snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
+                    snapped_point.setSecondSnapDistance(NR_HUGE);
+                    break;
+                default:
+                    g_assert_not_reached();
+            }
 
+            // When scaling, we're considering the best transformation in each direction separately. We will have a metric in each
+            // direction, whereas for all other transformation we only a single one-dimensional metric. That's why we need to handle
+            // the scaling metric differently
+            if (transformation_type == SCALE) {
+                for (int index = 0; index < 2; index++) {
+                    if (fabs(scale_metric[index]) < fabs(best_scale_metric[index])) {
+                        best_transformation[index] = result[index];
+                        best_scale_metric[index] = fabs(scale_metric[index]);
+                        // When scaling, we're considering the best transformation in each direction separately
+                        // Therefore two different snapped points might together make a single best transformation
+                        // We will however return only a single snapped point (e.g. to display the snapping indicator)
+                        best_snapped_point = snapped_point;
+                        // std::cout << "SEL ";
+                    } // else { std::cout << "    ";}
+                }
+                if (uniform) {
+                    if (best_scale_metric[0] < best_scale_metric[1]) {
+                        best_transformation[1] = best_transformation[0];
+                        best_scale_metric[1] = best_scale_metric[0];
+                    } else {
+                        best_transformation[0] = best_transformation[1];
+                        best_scale_metric[0] = best_scale_metric[1];
+                    }
+                }
+            } else { // For all transformations other than scaling
+                if (best_snapped_point.isOtherSnapBetter(snapped_point, true)) {
+                    best_transformation = result;
+                    best_snapped_point = snapped_point;
+                }
+            }
+        }
 
+        j++;
+    }
 
+    Geom::Coord best_metric;
+    if (transformation_type == SCALE) {
+        // When scaling, don't ever exit with one of scaling components set to NR_HUGE
+        for (int index = 0; index < 2; index++) {
+            if (best_transformation[index] == NR_HUGE) {
+                if (uniform && best_transformation[1-index] < NR_HUGE) {
+                    best_transformation[index] = best_transformation[1-index];
+                } else {
+                    best_transformation[index] = transformation[index];
+                }
+            }
+        }
+        best_metric = std::min(best_scale_metric[0], best_scale_metric[1]);
+    } else { // For all transformations other than scaling
+        best_metric = best_snapped_point.getSnapDistance();
+    }
 
+    best_snapped_point.setTransformation(best_transformation);
+    // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
+    // These rounding errors might be caused by NRRects, see bug #1584301
+    best_snapped_point.setSnapDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
+    return best_snapped_point;
+}
 
-/// Minimal distance to norm before point is considered for snap.
-static const double MIN_DIST_NORM = 1.0;
 
 /**
- * Try to snap \a req in one dimension.
+ *  Try to snap a list of points to any interested snappers after they have undergone
+ *  a translation.
  *
- * \param nv NamedView to use.
- * \param req Point to snap; updated to the snapped point if a snap occurred.
- * \param dim Dimension to snap in.
- * \return Distance to the snap point along the \a dim axis, or \c NR_HUGE
- *    if no snap occurred.
+ *  \param point_type Type of points.
+ *  \param p Points.
+ *  \param tr Proposed translation.
+ *  \return Snapped translation, if a snap occurred, and a flag indicating whether a snap occurred.
  */
-NR::Coord namedview_dim_snap(SPNamedView const *nv, Inkscape::Snapper::PointType t, NR::Point &req,
-                             NR::Dim2 const dim, SPItem const *it)
-{
-    return namedview_vector_snap(nv, t, req, component_vectors[dim], it);
-}
 
-NR::Coord namedview_dim_snap(SPNamedView const *nv, Inkscape::Snapper::PointType t, NR::Point &req,
-                             NR::Dim2 const dim, std::list<SPItem const *> const &it)
+Inkscape::SnappedPoint SnapManager::freeSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
+                                                        std::vector<std::pair<Geom::Point, int> > const &p,
+                                                        Geom::Point const &pointer,
+                                                        Geom::Point const &tr) const
 {
-    return namedview_vector_snap(nv, t, req, component_vectors[dim], it);
+    if (p.size() == 1) {
+        _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false), (p.at(0)).second));
+    }
+
+    return _snapTransformed(point_type, p, pointer, false, Geom::Point(0,0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
 }
 
 
-NR::Coord namedview_vector_snap(SPNamedView const *nv, Inkscape::Snapper::PointType t,
-                                NR::Point &req, NR::Point const &d,
-                                SPItem const *it)
+/**
+ *  Try to snap a list of points to any interested snappers after they have undergone a
+ *  translation.  A snap will only occur along a line described by a
+ *  Inkscape::Snapper::ConstraintLine.
+ *
+ *  \param point_type Type of points.
+ *  \param p Points.
+ *  \param constraint Constraint line.
+ *  \param tr Proposed translation.
+ *  \return Snapped translation, if a snap occurred, and a flag indicating whether a snap occurred.
+ */
+
+Inkscape::SnappedPoint SnapManager::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
 {
-    std::list<SPItem const *> lit;
-    lit.push_back(it);
-    return namedview_vector_snap(nv, t, req, d, lit);
+    if (p.size() == 1) {
+        _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false), (p.at(0)).second));
+    }
+
+    return _snapTransformed(point_type, p, pointer, true, constraint, TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
 }
 
+
 /**
- * Look for snap point along the line described by the point \a req
- * and the direction vector \a d.
- * Modifies req to the snap point, if one is found.
- * \return The distance from \a req to the snap point along the vector \a d,
- * or \c NR_HUGE if no snap point was found.
+ *  Try to snap a list of points to any interested snappers after they have undergone
+ *  a scale.
  *
- * \pre d \81â\89\81  (0, 0).
+ *  \param point_type Type of points.
+ *  \param p Points.
+ *  \param s Proposed scale.
+ *  \param o Origin of proposed scale.
+ *  \return Snapped scale, if a snap occurred, and a flag indicating whether a snap occurred.
  */
-NR::Coord namedview_vector_snap(SPNamedView const *nv, Inkscape::Snapper::PointType t,
-                                NR::Point &req, NR::Point const &d,
-                                std::list<SPItem const *> const &it)
-{
-    g_assert(nv != NULL);
-    g_assert(SP_IS_NAMEDVIEW(nv));
 
-    SnapManager::SnapperList const snappers = nv->snap_manager.getSnappers();
-
-    NR::Coord best = NR_HUGE;
-    for (SnapManager::SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
-        Inkscape::SnappedPoint const s = (*i)->constrainedSnap(t, req, d, it);
-        if (s.getDistance() < best) {
-            req = s.getPoint();
-            best = s.getDistance();
-        }
+Inkscape::SnappedPoint SnapManager::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
+{
+    if (p.size() == 1) {
+        _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false), (p.at(0)).second));
     }
 
-    return best;
+    return _snapTransformed(point_type, p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
 }
 
 
-/*
- * functions for lists of points
+/**
+ *  Try to snap a list of points to any interested snappers after they have undergone
+ *  a scale.  A snap will only occur along a line described by a
+ *  Inkscape::Snapper::ConstraintLine.
  *
- * All functions take a list of NR::Point and parameter indicating the proposed transformation.
- * They return the updated transformation parameter.
+ *  \param point_type Type of points.
+ *  \param p Points.
+ *  \param s Proposed scale.
+ *  \param o Origin of proposed scale.
+ *  \return Snapped scale, if a snap occurred, and a flag indicating whether a snap occurred.
  */
 
-/**
- * Snap list of points in one dimension.
- * \return Coordinate difference.
- */
-std::pair<NR::Coord, bool> namedview_dim_snap_list(SPNamedView const *nv, Inkscape::Snapper::PointType t,
-                                                   const std::vector<NR::Point> &p,
-                                                   NR::Coord const dx, NR::Dim2 const dim,
-                                                   std::list<SPItem const *> const &it
-                                                   )
+Inkscape::SnappedPoint SnapManager::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
 {
-    NR::Coord dist = NR_HUGE;
-    NR::Coord xdist = dx;
-
-    SnapManager const &m = nv->snap_manager;
-
-    if (m.willSnapSomething()) {
-        for (std::vector<NR::Point>::const_iterator i = p.begin(); i != p.end(); i++) {
-            NR::Point q = *i;
-            NR::Coord const pre = q[dim];
-            q[dim] += dx;
-            NR::Coord const d = namedview_dim_snap(nv, t, q, dim, it);
-            if (d < dist) {
-                xdist = q[dim] - pre;
-                dist = d;
-            }
-        }
+    // When constrained scaling, only uniform scaling is supported.
+    if (p.size() == 1) {
+        _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true), (p.at(0)).second));
     }
 
-    return std::make_pair(xdist, dist < NR_HUGE);
+    return _snapTransformed(point_type, p, pointer, true, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
 }
 
+
 /**
- * Snap list of points in two dimensions.
+ *  Try to snap a list of points to any interested snappers after they have undergone
+ *  a stretch.
+ *
+ *  \param point_type Type of points.
+ *  \param p Points.
+ *  \param s Proposed stretch.
+ *  \param o Origin of proposed stretch.
+ *  \param d Dimension in which to apply proposed stretch.
+ *  \param u true if the stretch should be uniform (ie to be applied equally in both dimensions)
+ *  \return Snapped stretch, if a snap occurred, and a flag indicating whether a snap occurred.
  */
-std::pair<double, bool> namedview_vector_snap_list(SPNamedView const *nv, Inkscape::Snapper::PointType t,
-                                                   const std::vector<NR::Point> &p, NR::Point const &norm,
-                                                   NR::scale const &s, std::list<SPItem const *> const &it)
+
+Inkscape::SnappedPoint SnapManager::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 u) const
 {
-    using NR::X;
-    using NR::Y;
-
-    SnapManager const &m = nv->snap_manager;
-
-    if (m.willSnapSomething() == false) {
-        return std::make_pair(s[X], false);
-    }
-
-    NR::Coord dist = NR_HUGE;
-    double ratio = fabs(s[X]);
-    for (std::vector<NR::Point>::const_iterator i = p.begin(); i != p.end(); i++) {
-        NR::Point const &q = *i;
-        NR::Point check = ( q - norm ) * s + norm;
-        if (NR::LInfty( q - norm ) > MIN_DIST_NORM) {
-            NR::Coord d = namedview_vector_snap(nv, t, check, check - norm, it);
-            if (d < dist) {
-                dist = d;
-                NR::Dim2 const dominant = ( ( fabs( q[X] - norm[X] )  >
-                                              fabs( q[Y] - norm[Y] ) )
-                                            ? X
-                                            : Y );
-                ratio = ( ( check[dominant] - norm[dominant] )
-                          / ( q[dominant] - norm[dominant] ) );
-            }
-        }
+    if (p.size() == 1) {
+        _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), STRETCH, Geom::Point(s, s), o, d, u), (p.at(0)).second));
     }
 
-    return std::make_pair(ratio, dist < NR_HUGE);
+    return _snapTransformed(point_type, p, pointer, true, Geom::Point(0,0), STRETCH, Geom::Point(s, s), o, d, u);
 }
 
 
 /**
- * Try to snap points in \a p after they have been scaled by \a sx with respect to
- * the origin \a norm.  The best snap is the one that changes the scale least.
+ *  Try to snap a list of points to any interested snappers after they have undergone
+ *  a skew.
  *
- * \return Pair containing snapped scale and a flag which is true if a snap was made.
+ *  \param point_type Type of points.
+ *  \param p Points.
+ *  \param s Proposed skew.
+ *  \param o Origin of proposed skew.
+ *  \param d Dimension in which to apply proposed skew.
+ *  \return Snapped skew, if a snap occurred, and a flag indicating whether a snap occurred.
  */
-std::pair<double, bool> namedview_dim_snap_list_scale(SPNamedView const *nv, Inkscape::Snapper::PointType t,
-                                                      const std::vector<NR::Point> &p, NR::Point const &norm,
-                                                      double const sx, NR::Dim2 dim,
-                                                      std::list<const SPItem *> const &it)
+
+Inkscape::SnappedPoint SnapManager::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,
+                                                 Geom::Point const &o,
+                                                 Geom::Dim2 d) const
 {
-    SnapManager const &m = nv->snap_manager;
-    if (m.willSnapSomething() == false) {
-        return std::make_pair(sx, false);
+    // "s" contains skew factor in s[0], and scale factor in s[1]
+
+    // Snapping the nodes of the boundingbox of a selection that is being transformed, will only work if
+    // the transformation of the bounding box is equal to the transformation of the individual nodes. This is
+    // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
+    // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
+    // of bounding boxes is not allowed here.
+    g_assert(!(point_type & Inkscape::SnapPreferences::SNAPPOINT_BBOX));
+
+    if (p.size() == 1) {
+        _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), SKEW, s, o, d, false), (p.at(0)).second));
     }
 
-    g_assert(dim < 2);
+    return _snapTransformed(point_type, p, pointer, true, constraint, SKEW, s, o, d, false);
+}
 
-    NR::Coord dist = NR_HUGE;
-    double scale = sx;
+Inkscape::SnappedPoint SnapManager::findBestSnap(Geom::Point const &p, Inkscape::SnapSourceType const source_type, SnappedConstraints &sc, bool constrained) const
+{
+
+    /*
+    std::cout << "Type and number of snapped constraints: " << std::endl;
+    std::cout << "  Points      : " << sc.points.size() << std::endl;
+    std::cout << "  Lines       : " << sc.lines.size() << std::endl;
+    std::cout << "  Grid lines  : " << sc.grid_lines.size()<< std::endl;
+    std::cout << "  Guide lines : " << sc.guide_lines.size()<< std::endl;
+    std::cout << "  Curves      : " << sc.curves.size()<< std::endl;
+    */
+
+    // Store all snappoints
+    std::list<Inkscape::SnappedPoint> sp_list;
+
+    // search for the closest snapped point
+    Inkscape::SnappedPoint closestPoint;
+    if (getClosestSP(sc.points, closestPoint)) {
+        sp_list.push_back(closestPoint);
+    }
 
-    for (std::vector<NR::Point>::const_iterator i = p.begin(); i != p.end(); i++) {
-        NR::Point q = *i;
-        NR::Point check = q;
+    // search for the closest snapped curve
+    Inkscape::SnappedCurve closestCurve;
+    if (getClosestCurve(sc.curves, closestCurve)) {
+        sp_list.push_back(Inkscape::SnappedPoint(closestCurve));
+    }
+
+    if (snapprefs.getSnapIntersectionCS()) {
+        // search for the closest snapped intersection of curves
+        Inkscape::SnappedPoint closestCurvesIntersection;
+        if (getClosestIntersectionCS(sc.curves, p, closestCurvesIntersection, _desktop->dt2doc())) {
+               closestCurvesIntersection.setSource(source_type);
+               sp_list.push_back(closestCurvesIntersection);
+        }
+    }
+
+    // search for the closest snapped grid line
+    Inkscape::SnappedLine closestGridLine;
+    if (getClosestSL(sc.grid_lines, closestGridLine)) {
+        closestGridLine.setTarget(Inkscape::SNAPTARGET_GRID);
+        sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
+    }
+
+    // search for the closest snapped guide line
+    Inkscape::SnappedLine closestGuideLine;
+    if (getClosestSL(sc.guide_lines, closestGuideLine)) {
+        closestGuideLine.setTarget(Inkscape::SNAPTARGET_GUIDE);
+        sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
+    }
+
+    // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
+    // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
+
+    // When doing a constrained snap however, we're already at an intersection of the constrained line and
+    // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
+    // no need to look for additional intersections
+    if (!constrained) {
+        // search for the closest snapped intersection of grid lines
+        Inkscape::SnappedPoint closestGridPoint;
+        if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
+               closestGridPoint.setSource(source_type);
+               closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
+            sp_list.push_back(closestGridPoint);
+        }
 
-        /* Scaled version of the point we are looking at */
-        check[dim] = (sx * (q - norm) + norm)[dim];
+        // search for the closest snapped intersection of guide lines
+        Inkscape::SnappedPoint closestGuidePoint;
+        if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
+               closestGuidePoint.setSource(source_type);
+               closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
+            sp_list.push_back(closestGuidePoint);
+        }
 
-        if (fabs (q[dim] - norm[dim]) > MIN_DIST_NORM) {
-            /* Snap this point */
-            const NR::Coord d = namedview_dim_snap (nv, t, check, dim, it);
-            /* Work out the resulting scale factor */
-            double snapped_scale = (check[dim] - norm[dim]) / (q[dim] - norm[dim]);
+        // search for the closest snapped intersection of grid with guide lines
+        if (snapprefs.getSnapIntersectionGG()) {
+            Inkscape::SnappedPoint closestGridGuidePoint;
+            if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
+               closestGridGuidePoint.setSource(source_type);
+               closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
+                sp_list.push_back(closestGridGuidePoint);
+            }
+        }
+    }
 
-            if (dist == NR_HUGE || fabs(snapped_scale - sx) < fabs(scale - sx)) {
-                /* This is either the first point, or the snapped scale
-                ** is the closest yet to the original.
-                */
-                scale = snapped_scale;
-                dist = d;
+    // now let's see which snapped point gets a thumbs up
+    Inkscape::SnappedPoint bestSnappedPoint = Inkscape::SnappedPoint(p, Inkscape::SNAPSOURCE_UNDEFINED, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
+    // std::cout << "Finding the best snap..." << std::endl;
+    for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
+        // first find out if this snapped point is within snapping range
+        // std::cout << "sp = " << from_2geom((*i).getPoint());
+        if ((*i).getSnapDistance() <= (*i).getTolerance()) {
+            // if it's the first point, or if it is closer than the best snapped point so far
+            if (i == sp_list.begin() || bestSnappedPoint.isOtherSnapBetter(*i, false)) {
+                // then prefer this point over the previous one
+                bestSnappedPoint = *i;
             }
         }
+        // std::cout << std::endl;
     }
 
-    return std::make_pair(scale, dist < NR_HUGE);
+    // Update the snap indicator, if requested
+    if (_snapindicator) {
+        if (bestSnappedPoint.getSnapped()) {
+            _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
+        } else {
+            _desktop->snapindicator->remove_snaptarget();
+        }
+    }
+
+    // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl;
+    return bestSnappedPoint;
 }
 
-/**
- * Try to snap points after they have been skewed.
- */
-double namedview_dim_snap_list_skew(SPNamedView const *nv, Inkscape::Snapper::PointType t,
-                                    const std::vector<NR::Point> &p, NR::Point const &norm,
-                                    double const sx, NR::Dim2 const dim)
+void SnapManager::setup(SPDesktop const *desktop, bool snapindicator, SPItem const *item_to_ignore, std::vector<std::pair<Geom::Point, int> > *unselected_nodes)
 {
-    SnapManager const &m = nv->snap_manager;
-
-    if (m.willSnapSomething() == false) {
-        return sx;
-    }
+    g_assert(desktop != NULL);
+    _item_to_ignore = item_to_ignore;
+    _items_to_ignore = NULL;
+    _desktop = desktop;
+    _snapindicator = snapindicator;
+    _unselected_nodes = unselected_nodes;
+}
 
-    g_assert(dim < 2);
+void SnapManager::setup(SPDesktop const *desktop, bool snapindicator, std::vector<SPItem const *> &items_to_ignore, std::vector<std::pair<Geom::Point, int> > *unselected_nodes)
+{
+    g_assert(desktop != NULL);
+    _item_to_ignore = NULL;
+    _items_to_ignore = &items_to_ignore;
+    _desktop = desktop;
+    _snapindicator = snapindicator;
+    _unselected_nodes = unselected_nodes;
+}
 
-    gdouble dist = NR_HUGE;
-    gdouble skew = sx;
+SPDocument *SnapManager::getDocument() const
+{
+    return _named_view->document;
+}
 
-    for (std::vector<NR::Point>::const_iterator i = p.begin(); i != p.end(); i++) {
-        NR::Point q = *i;
-        NR::Point check = q;
-        // apply shear
-        check[dim] += sx * (q[!dim] - norm[!dim]);
-        if (fabs (q[!dim] - norm[!dim]) > MIN_DIST_NORM) {
-            const gdouble d = namedview_dim_snap (nv, t, check, dim, NULL);
-            if (d < fabs (dist)) {
-                dist = d;
-                skew = (check[dim] - q[dim]) / (q[!dim] - norm[!dim]);
+Geom::Point SnapManager::_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
+{
+    /* Work out the transformed version of this point */
+    Geom::Point transformed;
+    switch (transformation_type) {
+        case TRANSLATION:
+            transformed = p.first + transformation;
+            break;
+        case SCALE:
+            transformed = (p.first - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
+            break;
+        case STRETCH:
+        {
+            Geom::Scale s(1, 1);
+            if (uniform)
+                s[Geom::X] = s[Geom::Y] = transformation[dim];
+            else {
+                s[dim] = transformation[dim];
+                s[1 - dim] = 1;
             }
+            transformed = ((p.first - origin) * s) + origin;
+            break;
         }
+        case SKEW:
+            // Apply the skew factor
+            transformed[dim] = (p.first)[dim] + transformation[0] * ((p.first)[1 - dim] - origin[1 - dim]);
+            // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
+            // Apply that scale factor here
+            transformed[1-dim] = (p.first - origin)[1 - dim] * transformation[1] + origin[1 - dim];
+            break;
+        default:
+            g_assert_not_reached();
     }
 
-    return skew;
+    return transformed;
 }
 
+void SnapManager::_displaySnapsource(Inkscape::SnapPreferences::PointType point_type, std::pair<Geom::Point, int> const &p) const {
+
+    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+    if (prefs->getBool("/options/snapclosestonly/value")) {
+        bool p_is_a_node = point_type & Inkscape::SnapPreferences::SNAPPOINT_NODE;
+        bool p_is_a_bbox = point_type & Inkscape::SnapPreferences::SNAPPOINT_BBOX;
+        if (snapprefs.getSnapEnabledGlobally() && ((p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) {
+            _desktop->snapindicator->set_new_snapsource(p);
+        } else {
+            _desktop->snapindicator->remove_snapsource();
+        }
+    }
+}
 
 /*
   Local Variables: