Code

Node tool: fix Tab and Shift+Tab
[inkscape.git] / src / ui / tool / path-manipulator.cpp
index 4b42c16b00f040a6bfb471dc521f704b0c1bad97..7c60efbabbef193183547e4583c8d0daa0a9e626 100644 (file)
@@ -3,6 +3,7 @@
  */
 /* Authors:
  *   Krzysztof KosiƄski <tweenk.pl@gmail.com>
+ *   Abhishek Sharma
  *
  * Copyright (C) 2009 Authors
  * Released under GNU GPL, read the file 'COPYING' for more information
@@ -58,8 +59,21 @@ enum PathChange {
  */
 class PathManipulatorObserver : public Inkscape::XML::NodeObserver {
 public:
-    PathManipulatorObserver(PathManipulator *p) : _pm(p), _blocked(false) {}
-    virtual void notifyAttributeChanged(Inkscape::XML::Node &, GQuark attr,
+    PathManipulatorObserver(PathManipulator *p, Inkscape::XML::Node *node)
+        : _pm(p)
+        , _node(node)
+        , _blocked(false)
+    {
+        Inkscape::GC::anchor(_node);
+        _node->addObserver(*this);
+    }
+
+    ~PathManipulatorObserver() {
+        _node->removeObserver(*this);
+        Inkscape::GC::release(_node);
+    }
+
+    virtual void notifyAttributeChanged(Inkscape::XML::Node &/*node*/, GQuark attr,
         Util::ptr_shared<char>, Util::ptr_shared<char>)
     {
         // do nothing if blocked
@@ -76,10 +90,12 @@ public:
             _pm->_externalChange(PATH_CHANGE_TRANSFORM);
         }
     }
+
     void block() { _blocked = true; }
     void unblock() { _blocked = false; }
 private:
     PathManipulator *_pm;
+    Inkscape::XML::Node *_node;
     bool _blocked;
 };
 
@@ -91,17 +107,20 @@ PathManipulator::PathManipulator(MultiPathManipulator &mpm, SPPath *path,
     , _subpaths(*this)
     , _multi_path_manipulator(mpm)
     , _path(path)
-    , _spcurve(NULL)
+    , _spcurve(new SPCurve())
     , _dragpoint(new CurveDragPoint(*this))
-    , _observer(new PathManipulatorObserver(this))
+    , /* XML Tree being used here directly while it shouldn't be*/_observer(new PathManipulatorObserver(this, SP_OBJECT(path)->getRepr()))
     , _edit_transform(et)
     , _num_selected(0)
     , _show_handles(true)
     , _show_outline(false)
+    , _show_path_direction(false)
+    , _live_outline(true)
+    , _live_objects(true)
     , _lpe_key(lpe_key)
 {
     if (_lpe_key.empty()) {
-        _i2d_transform = sp_item_i2d_affine(SP_ITEM(path));
+        _i2d_transform = SP_ITEM(path)->i2d_affine();
     } else {
         _i2d_transform = Geom::identity();
     }
@@ -116,34 +135,22 @@ PathManipulator::PathManipulator(MultiPathManipulator &mpm, SPPath *path,
         SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
     sp_canvas_bpath_set_fill(SP_CANVAS_BPATH(_outline), 0, SP_WIND_RULE_NONZERO);
 
-    _subpaths.signal_insert_node.connect(
-        sigc::mem_fun(*this, &PathManipulator::_attachNodeHandlers));
-    // NOTE: signal_remove_node is called just before destruction. Nodes are trackable,
-    // so removing the signals manually is not necessary.
-    /*_subpaths.signal_remove_node.connect(
-        sigc::mem_fun(*this, &PathManipulator::_removeNodeHandlers));*/
-
     _selection.signal_update.connect(
         sigc::mem_fun(*this, &PathManipulator::update));
     _selection.signal_point_changed.connect(
         sigc::mem_fun(*this, &PathManipulator::_selectionChanged));
-    _dragpoint->signal_update.connect(
-        sigc::mem_fun(*this, &PathManipulator::update));
     _desktop->signal_zoom_changed.connect(
         sigc::hide( sigc::mem_fun(*this, &PathManipulator::_updateOutlineOnZoomChange)));
 
     _createControlPointsFromGeometry();
-
-    _path->repr->addObserver(*_observer);
 }
 
 PathManipulator::~PathManipulator()
 {
     delete _dragpoint;
-    if (_path) _path->repr->removeObserver(*_observer);
     delete _observer;
     gtk_object_destroy(_outline);
-    if (_spcurve) _spcurve->unref();
+    _spcurve->unref();
     clear();
 }
 
@@ -176,6 +183,11 @@ void PathManipulator::update()
 /** Store the changes to the path in XML. */
 void PathManipulator::writeXML()
 {
+    if (!_live_outline)
+        _updateOutline();
+    if (!_live_objects)
+        _setGeometry();
+
     if (!_path) return;
     _observer->block();
     if (!empty()) {
@@ -203,7 +215,7 @@ void PathManipulator::clear()
 /** Select all nodes in subpaths that have something selected. */
 void PathManipulator::selectSubpaths()
 {
-    for (std::list<SubpathPtr>::iterator i = _subpaths.begin(); i != _subpaths.end(); ++i) {
+    for (SubpathList::iterator i = _subpaths.begin(); i != _subpaths.end(); ++i) {
         NodeList::iterator sp_start = (*i)->begin(), sp_end = (*i)->end();
         for (NodeList::iterator j = sp_start; j != sp_end; ++j) {
             if (j->selected()) {
@@ -217,63 +229,6 @@ void PathManipulator::selectSubpaths()
     }
 }
 
-/** Move the selection forward or backward by one node in each subpath, based on the sign
- * of the parameter. */
-void PathManipulator::shiftSelection(int dir)
-{
-    if (dir == 0) return;
-    if (_num_selected == 0) {
-        // select the first node of the path.
-        SubpathList::iterator s = _subpaths.begin();
-        if (s == _subpaths.end()) return;
-        NodeList::iterator n = (*s)->begin();
-        if (n != (*s)->end())
-            _selection.insert(n.ptr());
-        return;
-    }
-    // We cannot do any tricks here, like iterating in different directions based on
-    // the sign and only setting the selection of nodes behind us, because it would break
-    // for closed paths.
-    for (SubpathList::iterator i = _subpaths.begin(); i != _subpaths.end(); ++i) {
-        std::deque<bool> sels; // I hope this is specialized for bools!
-        unsigned num = 0;
-        
-        for (NodeList::iterator j = (*i)->begin(); j != (*i)->end(); ++j) {
-            sels.push_back(j->selected());
-            _selection.erase(j.ptr());
-            ++num;
-        }
-        if (num == 0) continue; // should never happen! zero-node subpaths are not allowed
-
-        num = 0;
-        // In closed subpath, shift the selection cyclically. In an open one,
-        // let the selection 'slide into nothing' at ends.
-        if (dir > 0) {
-            if ((*i)->closed()) {
-                bool last = sels.back();
-                sels.pop_back();
-                sels.push_front(last);
-            } else {
-                sels.push_front(false);
-            }
-        } else {
-            if ((*i)->closed()) {
-                bool first = sels.front();
-                sels.pop_front();
-                sels.push_back(first);
-            } else {
-                sels.push_back(false);
-                num = 1;
-            }
-        }
-
-        for (NodeList::iterator j = (*i)->begin(); j != (*i)->end(); ++j) {
-            if (sels[num]) _selection.insert(j.ptr());
-            ++num;
-        }
-    }
-}
-
 /** Invert selection in the selected subpaths. */
 void PathManipulator::invertSelectionInSubpaths()
 {
@@ -308,6 +263,39 @@ void PathManipulator::insertNodes()
     }
 }
 
+/** Insert new nodes exactly at the positions of selected nodes while preserving shape.
+ * This is equivalent to breaking, except that it doesn't split into subpaths. */
+void PathManipulator::duplicateNodes()
+{
+    if (_num_selected == 0) return;
+
+    for (SubpathList::iterator i = _subpaths.begin(); i != _subpaths.end(); ++i) {
+        for (NodeList::iterator j = (*i)->begin(); j != (*i)->end(); ++j) {
+            if (j->selected()) {
+                NodeList::iterator k = j.next();
+                Node *n = new Node(_multi_path_manipulator._path_data.node_data, *j);
+
+                // Move the new node to the bottom of the Z-order. This way you can drag all
+                // nodes that were selected before this operation without deselecting
+                // everything because there is a new node above.
+                n->sink();
+
+                n->front()->setPosition(*j->front());
+                j->front()->retract();
+                j->setType(NODE_CUSP, false);
+                (*i)->insert(k, n);
+
+                // We need to manually call the selection change callback to refresh
+                // the handle display correctly.
+                // This call changes num_selected, but we call this once for a selected node
+                // and once for an unselected node, so in the end the number stays correct.
+                _selectionChanged(j.ptr(), true);
+                _selectionChanged(n, false);
+            }
+        }
+    }
+}
+
 /** Replace contiguous selections of nodes in each subpath with one node. */
 void PathManipulator::weldNodes(NodeList::iterator preserve_pos)
 {
@@ -521,7 +509,7 @@ void PathManipulator::deleteNodes(bool keep_shape)
         sel_end = sel_beg;
         
         while (num_selected > 0) {
-            while (!sel_beg->selected()) {
+            while (sel_beg && !sel_beg->selected()) {
                 sel_beg = sel_beg.next();
             }
             sel_end = sel_beg;
@@ -531,6 +519,7 @@ void PathManipulator::deleteNodes(bool keep_shape)
             }
             
             num_selected -= _deleteStretch(sel_beg, sel_end, keep_shape);
+            sel_beg = sel_end;
         }
         ++i;
     }
@@ -586,10 +575,10 @@ unsigned PathManipulator::_deleteStretch(NodeList::iterator start, NodeList::ite
 
     // We can't use nl->erase(start, end), because it would break when the stretch
     // crosses the beginning of a closed subpath
-    NodeList *nl = start->list();
+    NodeList &nl = start->nodeList();
     while (start != end) {
         NodeList::iterator next = start.next();
-        nl->erase(start);
+        nl.erase(start);
         start = next;
     }
 
@@ -708,6 +697,7 @@ void PathManipulator::setSegmentType(SegmentType type)
             case SEGMENT_CUBIC_BEZIER:
                 if (!j->front()->isDegenerate() || !k->back()->isDegenerate())
                     break;
+                // move both handles to 1/3 of the line
                 j->front()->move(j->position() + (k->position() - j->position()) / 3);
                 k->back()->move(k->position() + (j->position() - k->position()) / 3);
                 break;
@@ -716,6 +706,90 @@ void PathManipulator::setSegmentType(SegmentType type)
     }
 }
 
+void PathManipulator::scaleHandle(Node *n, int which, int dir, bool pixel)
+{
+    if (n->type() == NODE_SYMMETRIC || n->type() == NODE_AUTO) {
+        n->setType(NODE_SMOOTH);
+    }
+    Handle *h = _chooseHandle(n, which);
+    double length_change;
+
+    if (pixel) {
+        length_change = 1.0 / _desktop->current_zoom() * dir;
+    } else {
+        Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+        length_change = prefs->getDoubleLimited("/options/defaultscale/value", 2, 1, 1000);
+        length_change *= dir;
+    }
+
+    Geom::Point relpos;
+    if (h->isDegenerate()) {
+        if (dir < 0) return;
+        Node *nh = n->nodeToward(h);
+        if (!nh) return;
+        relpos = Geom::unit_vector(nh->position() - n->position()) * length_change;
+    } else {
+        relpos = h->relativePos();
+        double rellen = relpos.length();
+        relpos *= ((rellen + length_change) / rellen);
+    }
+    h->setRelativePos(relpos);
+    update();
+
+    gchar const *key = which < 0 ? "handle:scale:left" : "handle:scale:right";
+    _commit(_("Scale handle"), key);
+}
+
+void PathManipulator::rotateHandle(Node *n, int which, int dir, bool pixel)
+{
+    if (n->type() != NODE_CUSP) {
+        n->setType(NODE_CUSP);
+    }
+    Handle *h = _chooseHandle(n, which);
+    if (h->isDegenerate()) return;
+
+    double angle;
+    if (pixel) {
+        // Rotate by "one pixel"
+        angle = atan2(1.0 / _desktop->current_zoom(), h->length()) * dir;
+    } else {
+        Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+        int snaps = prefs->getIntLimited("/options/rotationsnapsperpi/value", 12, 1, 1000);
+        angle = M_PI * dir / snaps;
+    }
+
+    h->setRelativePos(h->relativePos() * Geom::Rotate(angle));
+    update();
+    gchar const *key = which < 0 ? "handle:rotate:left" : "handle:rotate:right";
+    _commit(_("Rotate handle"), key);
+}
+
+Handle *PathManipulator::_chooseHandle(Node *n, int which)
+{
+    NodeList::iterator i = NodeList::get_iterator(n);
+    Node *prev = i.prev().ptr();
+    Node *next = i.next().ptr();
+
+    // on an endnode, the remaining handle automatically wins
+    if (!next) return n->back();
+    if (!prev) return n->front();
+
+    // compare X coord ofline segments
+    Geom::Point npos = next->position();
+    Geom::Point ppos = prev->position();
+    if (which < 0) {
+        // pick left handle.
+        // we just swap the handles and pick the right handle below.
+        std::swap(npos, ppos);
+    }
+
+    if (npos[Geom::X] >= ppos[Geom::X]) {
+        return n->front();
+    } else {
+        return n->back();
+    }
+}
+
 /** Set the visibility of handles. */
 void PathManipulator::showHandles(bool show)
 {
@@ -754,6 +828,16 @@ void PathManipulator::showPathDirection(bool show)
     _updateOutline();
 }
 
+void PathManipulator::setLiveOutline(bool set)
+{
+    _live_outline = set;
+}
+
+void PathManipulator::setLiveObjects(bool set)
+{
+    _live_objects = set;
+}
+
 void PathManipulator::setControlsTransform(Geom::Matrix const &tnew)
 {
     Geom::Matrix delta = _i2d_transform.inverse() * _edit_transform.inverse() * tnew * _i2d_transform;
@@ -852,6 +936,8 @@ NodeList::iterator PathManipulator::extremeNode(NodeList::iterator origin, bool
 /** Called by the XML observer when something else than us modifies the path. */
 void PathManipulator::_externalChange(unsigned type)
 {
+    hideDragPoint();
+
     switch (type) {
     case PATH_CHANGE_D: {
         _getGeometry();
@@ -881,7 +967,7 @@ void PathManipulator::_externalChange(unsigned type)
         } break;
     case PATH_CHANGE_TRANSFORM: {
         Geom::Matrix i2d_change = _d2i_transform;
-        _i2d_transform = sp_item_i2d_affine(SP_ITEM(_path));
+        _i2d_transform = SP_ITEM(_path)->i2d_affine();
         _d2i_transform = _i2d_transform.inverse();
         i2d_change *= _i2d_transform;
         for (SubpathList::iterator i = _subpaths.begin(); i != _subpaths.end(); ++i) {
@@ -904,8 +990,14 @@ void PathManipulator::_createControlPointsFromGeometry()
     // so that _updateDragPoint doesn't crash on paths with naked movetos
     Geom::PathVector pathv = pathv_to_linear_and_cubic_beziers(_spcurve->get_pathvector());
     for (Geom::PathVector::iterator i = pathv.begin(); i != pathv.end(); ) {
-        if (i->empty()) pathv.erase(i++);
-        else ++i;
+        // NOTE: this utilizes the fact that Geom::PathVector is an std::vector.
+        // When we erase an element, the next one slides into position,
+        // so we do not increment the iterator even though it is theoretically invalidated.
+        if (i->empty()) {
+            pathv.erase(i);
+        } else {
+            ++i;
+        }
     }
     _spcurve->set_pathvector(pathv);
 
@@ -955,7 +1047,10 @@ void PathManipulator::_createControlPointsFromGeometry()
     // we need to set the nodetypes after all the handles are in place,
     // so that pickBestType works correctly
     // TODO maybe migrate to inkscape:node-types?
-    gchar const *nts_raw = _path ? _path->repr->attribute(_nodetypesKey().data()) : 0;
+    // TODO move this into SPPath - do not manipulate directly
+
+    //XML Tree being used here directly while it shouldn't be.
+    gchar const *nts_raw = _path ? _path->getRepr()->attribute(_nodetypesKey().data()) : 0;
     std::string nodetype_string = nts_raw ? nts_raw : "";
     /* Calculate the needed length of the nodetype string.
      * For closed paths, the entry is duplicated for the starting node,
@@ -1016,8 +1111,10 @@ void PathManipulator::_createGeometryFromControlPoints()
     }
     builder.finish();
     _spcurve->set_pathvector(builder.peek() * (_edit_transform * _i2d_transform).inverse());
-    _updateOutline();
-    _setGeometry();
+    if (_live_outline)
+        _updateOutline();
+    if (_live_objects)
+        _setGeometry();
 }
 
 /** Build one segment of the geometric representation.
@@ -1102,13 +1199,11 @@ void PathManipulator::_getGeometry()
         Effect *lpe = LIVEPATHEFFECT(_path)->get_lpe();
         if (lpe) {
             PathParam *pathparam = dynamic_cast<PathParam *>(lpe->getParameter(_lpe_key.data()));
-            if (!_spcurve)
-                _spcurve = new SPCurve(pathparam->get_pathvector());
-            else
-                _spcurve->set_pathvector(pathparam->get_pathvector());
+            _spcurve->unref();
+            _spcurve = new SPCurve(pathparam->get_pathvector());
         }
     } else {
-        if (_spcurve) _spcurve->unref();
+        _spcurve->unref();
         _spcurve = sp_path_get_curve_for_edit(_path);
     }
 }
@@ -1130,10 +1225,11 @@ void PathManipulator::_setGeometry()
             LIVEPATHEFFECT(_path)->requestModified(SP_OBJECT_MODIFIED_FLAG);
         }
     } else {
-        if (_path->repr->attribute("inkscape:original-d"))
-            sp_path_set_original_curve(_path, _spcurve, true, false);
+        //XML Tree being used here directly while it shouldn't be.
+        if (_path->getRepr()->attribute("inkscape:original-d"))
+            sp_path_set_original_curve(_path, _spcurve, false, false);
         else
-            sp_shape_set_curve(SP_SHAPE(_path), _spcurve, false);
+            SP_SHAPE(_path)->setCurve(_spcurve, false);
     }
 }
 
@@ -1148,48 +1244,24 @@ Glib::ustring PathManipulator::_nodetypesKey()
  * This method is wrong but necessary at the moment. */
 Inkscape::XML::Node *PathManipulator::_getXMLNode()
 {
-    if (_lpe_key.empty()) return _path->repr;
-    return LIVEPATHEFFECT(_path)->repr;
-}
-
-void PathManipulator::_attachNodeHandlers(Node *node)
-{
-    Handle *handles[2] = { node->front(), node->back() };
-    for (int i = 0; i < 2; ++i) {
-        handles[i]->signal_update.connect(
-            sigc::mem_fun(*this, &PathManipulator::update));
-        handles[i]->signal_ungrabbed.connect(
-            sigc::hide(
-                sigc::mem_fun(*this, &PathManipulator::_handleUngrabbed)));
-        handles[i]->signal_grabbed.connect(
-            sigc::bind_return(
-                sigc::hide(
-                    sigc::mem_fun(*this, &PathManipulator::_handleGrabbed)),
-                false));
-        handles[i]->signal_clicked.connect(
-            sigc::bind<0>(
-                sigc::mem_fun(*this, &PathManipulator::_handleClicked),
-                handles[i]));
-    }
-    node->signal_clicked.connect(
-        sigc::bind<0>(
-            sigc::mem_fun(*this, &PathManipulator::_nodeClicked),
-            node));
+    //XML Tree being used here directly while it shouldn't be.
+    if (_lpe_key.empty()) return _path->getRepr();
+    //XML Tree being used here directly while it shouldn't be.
+    return LIVEPATHEFFECT(_path)->getRepr();
 }
 
 bool PathManipulator::_nodeClicked(Node *n, GdkEventButton *event)
 {
-    // cycle between node types on ctrl+click
     if (event->button != 1) return false;
     if (held_alt(*event) && held_control(*event)) {
         // Ctrl+Alt+click: delete nodes
         hideDragPoint();
         NodeList::iterator iter = NodeList::get_iterator(n);
-        NodeList *nl = iter->list();
+        NodeList &nl = iter->nodeList();
 
-        if (nl->size() <= 1 || (nl->size() <= 2 && !nl->closed())) {
+        if (nl.size() <= 1 || (nl.size() <= 2 && !nl.closed())) {
             // Removing last node of closed path - delete it
-            nl->kill();
+            nl.kill();
         } else {
             // In other cases, delete the node under cursor
             _deleteStretch(iter, iter.next(), true);
@@ -1204,17 +1276,11 @@ bool PathManipulator::_nodeClicked(Node *n, GdkEventButton *event)
         return true;
     } else if (held_control(*event)) {
         // Ctrl+click: cycle between node types
-        if (n->isEndNode()) {
-            if (n->type() == NODE_CUSP) {
-                n->setType(NODE_SMOOTH);
-            } else {
-                n->setType(NODE_CUSP);
-            }
-        } else {
+        if (!n->isEndNode()) {
             n->setType(static_cast<NodeType>((n->type() + 1) % NODE_LAST_REAL_TYPE));
+            update();
+            _commit(_("Cycle node type"));
         }
-        update();
-        _commit(_("Cycle node type"));
         return true;
     }
     return false;
@@ -1245,6 +1311,9 @@ bool PathManipulator::_handleClicked(Handle *h, GdkEventButton *event)
 
 void PathManipulator::_selectionChanged(SelectableControlPoint *p, bool selected)
 {
+    if (selected) ++_num_selected;
+    else --_num_selected;
+
     // don't do anything if we do not show handles
     if (!_show_handles) return;
 
@@ -1279,9 +1348,6 @@ void PathManipulator::_selectionChanged(SelectableControlPoint *p, bool selected
             }
         }
     }
-
-    if (selected) ++_num_selected;
-    else --_num_selected;
 }
 
 /** Removes all nodes belonging to this manipulator from the control pont selection */
@@ -1299,19 +1365,26 @@ void PathManipulator::_removeNodesFromSelection()
 void PathManipulator::_commit(Glib::ustring const &annotation)
 {
     writeXML();
-    sp_document_done(sp_desktop_document(_desktop), SP_VERB_CONTEXT_NODE, annotation.data());
+    DocumentUndo::done(sp_desktop_document(_desktop), SP_VERB_CONTEXT_NODE, annotation.data());
+}
+
+void PathManipulator::_commit(Glib::ustring const &annotation, gchar const *key)
+{
+    writeXML();
+    DocumentUndo::maybeDone(sp_desktop_document(_desktop), key, SP_VERB_CONTEXT_NODE,
+                            annotation.data());
 }
 
 /** Update the position of the curve drag point such that it is over the nearest
  * point of the path. */
 void PathManipulator::_updateDragPoint(Geom::Point const &evp)
 {
-    // TODO find a way to make this faster (no transform required)
-    Geom::PathVector pv = _spcurve->get_pathvector() * (_edit_transform * _i2d_transform);
+    Geom::Matrix to_desktop = _edit_transform * _i2d_transform;
+    Geom::PathVector pv = _spcurve->get_pathvector();
     boost::optional<Geom::PathVectorPosition> pvp
-        = Geom::nearestPoint(pv, _desktop->w2d(evp));
+        = Geom::nearestPoint(pv, _desktop->w2d(evp) * to_desktop.inverse());
     if (!pvp) return;
-    Geom::Point nearest_point = _desktop->d2w(pv.at(pvp->path_nr).pointAt(pvp->t));
+    Geom::Point nearest_point = _desktop->d2w(pv.at(pvp->path_nr).pointAt(pvp->t) * to_desktop);
     
     double fracpart;
     std::list<SubpathPtr>::iterator spi = _subpaths.begin();
@@ -1319,7 +1392,10 @@ void PathManipulator::_updateDragPoint(Geom::Point const &evp)
     NodeList::iterator first = (*spi)->before(pvp->t, &fracpart);
     
     double stroke_tolerance = _getStrokeTolerance();
-    if (Geom::distance(evp, nearest_point) < stroke_tolerance) {
+    if (first && first.next() &&
+        fracpart != 0.0 &&
+        Geom::distance(evp, nearest_point) < stroke_tolerance)
+    {
         _dragpoint->setVisible(true);
         _dragpoint->setPosition(_desktop->w2d(nearest_point));
         _dragpoint->setSize(2 * stroke_tolerance);
@@ -1344,7 +1420,7 @@ double PathManipulator::_getStrokeTolerance()
      * drag tolerance setting.  */
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
     double ret = prefs->getIntLimited("/options/dragtolerance/value", 2, 0, 100);
-    if (_path && !SP_OBJECT_STYLE(_path)->stroke.isNone()) {
+    if (_path && SP_OBJECT_STYLE(_path) && !SP_OBJECT_STYLE(_path)->stroke.isNone()) {
         ret += SP_OBJECT_STYLE(_path)->stroke_width.computed * 0.5
             * (_edit_transform * _i2d_transform).descrim() // scale to desktop coords
             * _desktop->current_zoom(); // == _d2w.descrim() - scale to window coords
@@ -1364,4 +1440,4 @@ double PathManipulator::_getStrokeTolerance()
   fill-column:99
   End:
 */
-// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :