Code

Allow snapping to objects in hidden layers
[inkscape.git] / src / object-snapper.cpp
1 /**
2  *  \file object-snapper.cpp
3  *  \brief Snapping things to objects.
4  *
5  * Authors:
6  *   Carl Hetherington <inkscape@carlh.net>
7  *   Diederik van Lierop <mail@diedenrezi.nl>
8  *
9  * Copyright (C) 2005 - 2008 Authors
10  *
11  * Released under GNU GPL, read the file 'COPYING' for more information
12  */
14 #include "svg/svg.h"
15 #include "libnr/nr-rect-ops.h"
16 #include "libnr/nr-point-fns.h"
17 #include <2geom/path-intersection.h>
18 #include <2geom/point.h>
19 #include <2geom/rect.h>
20 #include "document.h"
21 #include "sp-namedview.h"
22 #include "sp-image.h"
23 #include "sp-item-group.h"
24 #include "sp-item.h"
25 #include "sp-use.h"
26 #include "display/curve.h"
27 #include "inkscape.h"
28 #include "preferences.h"
29 #include "sp-text.h"
30 #include "sp-flowtext.h"
31 #include "text-editing.h"
32 #include "sp-clippath.h"
33 #include "sp-mask.h"
34 #include "helper/geom-curves.h"
35 #include "desktop.h"
37 Inkscape::SnapCandidate::SnapCandidate(SPItem* item, bool clip_or_mask, Geom::Matrix additional_affine)
38     : item(item), clip_or_mask(clip_or_mask), additional_affine(additional_affine)
39 {
40 }
42 Inkscape::SnapCandidate::~SnapCandidate()
43 {
44 }
46 Inkscape::ObjectSnapper::ObjectSnapper(SnapManager *sm, Geom::Coord const d)
47     : Snapper(sm, d)
48 {
49     _candidates = new std::vector<SnapCandidate>;
50     _points_to_snap_to = new std::vector<std::pair<Geom::Point, int> >;
51     _paths_to_snap_to = new std::vector<std::pair<Geom::PathVector*, SnapTargetType> >;
52 }
54 Inkscape::ObjectSnapper::~ObjectSnapper()
55 {
56     _candidates->clear();
57     delete _candidates;
59     _points_to_snap_to->clear();
60     delete _points_to_snap_to;
62     _clear_paths();
63     delete _paths_to_snap_to;
64 }
66 /**
67  *  \return Snap tolerance (desktop coordinates); depends on current zoom so that it's always the same in screen pixels
68  */
69 Geom::Coord Inkscape::ObjectSnapper::getSnapperTolerance() const
70 {
71         SPDesktop const *dt = _snapmanager->getDesktop();
72         double const zoom =  dt ? dt->current_zoom() : 1;
73         return _snapmanager->snapprefs.getObjectTolerance() / zoom;
74 }
76 bool Inkscape::ObjectSnapper::getSnapperAlwaysSnap() const
77 {
78     return _snapmanager->snapprefs.getObjectTolerance() == 10000; //TODO: Replace this threshold of 10000 by a constant; see also tolerance-slider.cpp
79 }
81 /**
82  *  Find all items within snapping range.
83  *  \param parent Pointer to the document's root, or to a clipped path or mask object
84  *  \param it List of items to ignore
85  *  \param first_point If true then this point is the first one from a whole bunch of points
86  *  \param bbox_to_snap Bounding box hulling the whole bunch of points, all from the same selection and having the same transformation
87  *  \param DimensionToSnap Snap in X, Y, or both directions.
88  */
90 void Inkscape::ObjectSnapper::_findCandidates(SPObject* parent,
91                                               std::vector<SPItem const *> const *it,
92                                               bool const &first_point,
93                                               Geom::Rect const &bbox_to_snap,
94                                               DimensionToSnap const snap_dim,
95                                               bool const clip_or_mask,
96                                               Geom::Matrix const additional_affine) const // transformation of the item being clipped / masked
97 {
98     bool const c1 = (snap_dim == TRANSL_SNAP_XY) && ThisSnapperMightSnap();
99     bool const c2 = (snap_dim != TRANSL_SNAP_XY) && GuidesMightSnap();
101     if (!(c1 || c2)) {
102         return;
103     }
105     if (first_point) {
106         _candidates->clear();
107     }
109     Geom::Rect bbox_to_snap_incl = bbox_to_snap; // _incl means: will include the snapper tolerance
110     bbox_to_snap_incl.expandBy(getSnapperTolerance()); // see?
112     for (SPObject* o = sp_object_first_child(parent); o != NULL; o = SP_OBJECT_NEXT(o)) {
113         g_assert(_snapmanager->getDesktop() != NULL);
114         if (SP_IS_ITEM(o) && !(_snapmanager->getDesktop()->itemIsHidden(SP_ITEM(o)) && !clip_or_mask)) {
115             // Snapping to items in a locked layer is allowed
116             // Don't snap to hidden objects, unless they're a clipped path or a mask
117             /* See if this item is on the ignore list */
118             std::vector<SPItem const *>::const_iterator i;
119             if (it != NULL) {
120                 i = it->begin();
121                 while (i != it->end() && *i != o) {
122                     i++;
123                 }
124             }
126             if (it == NULL || i == it->end()) {
127                 SPItem *item = SP_ITEM(o);
128                 if (item) {
129                     SPObject *obj = NULL;
130                     if (!clip_or_mask) { // cannot clip or mask more than once
131                         // The current item is not a clipping path or a mask, but might
132                         // still be the subject of clipping or masking itself ; if so, then
133                         // we should also consider that path or mask for snapping to
134                         obj = SP_OBJECT(item->clip_ref->getObject());
135                         if (obj) {
136                             _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
137                         }
138                         obj = SP_OBJECT(item->mask_ref->getObject());
139                         if (obj) {
140                             _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
141                         }
142                     }
143                 }
145                 if (SP_IS_GROUP(o)) {
146                     _findCandidates(o, it, false, bbox_to_snap, snap_dim, clip_or_mask, additional_affine);
147                 } else {
148                     Geom::OptRect bbox_of_item = Geom::Rect();
149                     if (clip_or_mask) {
150                         // Oh oh, this will get ugly. We cannot use sp_item_i2d_affine directly because we need to
151                         // insert an additional transformation in document coordinates (code copied from sp_item_i2d_affine)
152                         sp_item_invoke_bbox(item,
153                             bbox_of_item,
154                             sp_item_i2doc_affine(item) * additional_affine * _snapmanager->getDesktop()->doc2dt(),
155                             true);
156                     } else {
157                         sp_item_invoke_bbox(item, bbox_of_item, sp_item_i2d_affine(item), true);
158                     }
159                     if (bbox_of_item) {
160                         // See if the item is within range
161                         if (bbox_to_snap_incl.intersects(*bbox_of_item)) {
162                             // This item is within snapping range, so record it as a candidate
163                             _candidates->push_back(SnapCandidate(item, clip_or_mask, additional_affine));
164                         }
165                     }
166                 }
167             }
168         }
169     }
173 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::SnapPreferences::PointType const &t,
174                                          bool const &first_point) const
176     // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
177     // e.g. when translating an item using the selector tool, then we will only do this for the
178     // first point and store the collection for later use. This significantly improves the performance
179     if (first_point) {
180         _points_to_snap_to->clear();
182          // Determine the type of bounding box we should snap to
183         SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
185         bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
186         bool p_is_a_bbox = t & Inkscape::SnapPreferences::SNAPPOINT_BBOX;
187         bool p_is_a_guide = t & Inkscape::SnapPreferences::SNAPPOINT_GUIDE;
189         // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
190         g_assert(!((p_is_a_node && p_is_a_bbox) || (p_is_a_bbox && p_is_a_guide) || (p_is_a_node && p_is_a_guide)));
192         if (_snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()) {
193             Inkscape::Preferences *prefs = Inkscape::Preferences::get();
194             bool prefs_bbox = prefs->getBool("/tools/bounding_box");
195             bbox_type = !prefs_bbox ?
196                 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
197         }
199         // Consider the page border for snapping to
200         if (_snapmanager->snapprefs.getSnapToPageBorder()) {
201             _getBorderNodes(_points_to_snap_to);
202         }
204         for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
205             //Geom::Matrix i2doc(Geom::identity());
206             SPItem *root_item = (*i).item;
207             if (SP_IS_USE((*i).item)) {
208                 root_item = sp_use_root(SP_USE((*i).item));
209             }
210             g_return_if_fail(root_item);
212             //Collect all nodes so we can snap to them
213                         if (p_is_a_node || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node) || p_is_a_guide) {
214                                 // Note: there are two ways in which intersections are considered:
215                                 // Method 1: Intersections are calculated for each shape individually, for both the
216                                 //           snap source and snap target (see sp_shape_snappoints)
217                                 // Method 2: Intersections are calculated for each curve or line that we've snapped to, i.e. only for
218                                 //           the target (see the intersect() method in the SnappedCurve and SnappedLine classes)
219                                 // Some differences:
220                                 // - Method 1 doesn't find intersections within a set of multiple objects
221                                 // - Method 2 only works for targets
222                                 // When considering intersections as snap targets:
223                                 // - Method 1 only works when snapping to nodes, whereas
224                                 // - Method 2 only works when snapping to paths
225                                 // - There will be performance differences too!
226                                 // If both methods are being used simultaneously, then this might lead to duplicate targets!
228                                 // Well, here we will be looking for snap TARGETS. Both methods can therefore be used.
229                                 // When snapping to paths, we will get a collection of snapped lines and snapped curves. findBestSnap() will
230                                 // go hunting for intersections (but only when asked to in the prefs of course). In that case we can just
231                                 // temporarily block the intersections in sp_item_snappoints, we don't need duplicates. If we're not snapping to
232                                 // paths though but only to item nodes then we should still look for the intersections in sp_item_snappoints()
233                                 bool old_pref = _snapmanager->snapprefs.getSnapIntersectionCS();
234                                 if (_snapmanager->snapprefs.getSnapToItemPath()) {
235                                         _snapmanager->snapprefs.setSnapIntersectionCS(false);
236                                 }
238                                 sp_item_snappoints(root_item, true, *_points_to_snap_to, &_snapmanager->snapprefs);
240                                 if (_snapmanager->snapprefs.getSnapToItemPath()) {
241                                         _snapmanager->snapprefs.setSnapIntersectionCS(old_pref);
242                                 }
243                         }
245             //Collect the bounding box's corners so we can snap to them
246                         if (p_is_a_bbox || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_bbox) || p_is_a_guide) {
247                                 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
248                                 // of the item AND the bbox of the clipping path at the same time
249                                 if (!(*i).clip_or_mask) {
250                                         Geom::OptRect b = sp_item_bbox_desktop(root_item, bbox_type);
251                                         getBBoxPoints(b, _points_to_snap_to, true, _snapmanager->snapprefs.getSnapToBBoxNode(), _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints(), _snapmanager->snapprefs.getSnapBBoxMidpoints());
252                                 }
253                         }
254         }
255     }
258 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
259                                          Inkscape::SnapPreferences::PointType const &t,
260                                          Geom::Point const &p,
261                                          SnapSourceType const &source_type,
262                                          bool const &first_point,
263                                          std::vector<std::pair<Geom::Point, int> > *unselected_nodes) const
265     // Iterate through all nodes, find out which one is the closest to p, and snap to it!
267     _collectNodes(t, first_point);
269     if (unselected_nodes != NULL) {
270         _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
271     }
273     SnappedPoint s;
274     bool success = false;
276     for (std::vector<std::pair<Geom::Point, int> >::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
277         Geom::Coord dist = Geom::L2((*k).first - p);
278         if (dist < getSnapperTolerance() && dist < s.getSnapDistance()) {
279             s = SnappedPoint((*k).first, source_type, static_cast<Inkscape::SnapTargetType>((*k).second), dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
280             success = true;
281         }
282     }
284     if (success) {
285         sc.points.push_back(s);
286     }
289 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
290                                          Inkscape::SnapPreferences::PointType const &t,
291                                          Geom::Point const &p,
292                                          Geom::Point const &guide_normal) const
294     // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
295     _collectNodes(t, true);
297     SnappedPoint s;
298     bool success = false;
300     Geom::Coord tol = getSnapperTolerance();
302     for (std::vector<std::pair<Geom::Point, int> >::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
303         // Project each node (*k) on the guide line (running through point p)
304         Geom::Point p_proj = project_on_linesegment((*k).first, p, p + Geom::rot90(guide_normal));
305         Geom::Coord dist = Geom::L2((*k).first - p_proj); // distance from node to the guide
306         Geom::Coord dist2 = Geom::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
307         if ((dist < tol && dist2 < tol) || (getSnapperAlwaysSnap() && dist < s.getSnapDistance())) {
308             s = SnappedPoint((*k).first, SNAPSOURCE_GUIDE, static_cast<Inkscape::SnapTargetType>((*k).second), dist, tol, getSnapperAlwaysSnap(), true);
309             success = true;
310         }
311     }
313     if (success) {
314         sc.points.push_back(s);
315     }
319 /**
320  * Returns index of first NR_END bpath in array.
321  */
323 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::SnapPreferences::PointType const &t,
324                                          bool const &first_point) const
326     // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
327     // e.g. when translating an item using the selector tool, then we will only do this for the
328     // first point and store the collection for later use. This significantly improves the performance
329     if (first_point) {
330         _clear_paths();
332         // Determine the type of bounding box we should snap to
333         SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
335         bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
337         if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
338             Inkscape::Preferences *prefs = Inkscape::Preferences::get();
339             int prefs_bbox = prefs->getBool("/tools/bounding_box", 0);
340             bbox_type = !prefs_bbox ?
341                 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
342         }
344         // Consider the page border for snapping
345         if (_snapmanager->snapprefs.getSnapToPageBorder()) {
346             Geom::PathVector *border_path = _getBorderPathv();
347             if (border_path != NULL) {
348                 _paths_to_snap_to->push_back(std::make_pair(border_path, SNAPTARGET_PAGE_BORDER));
349             }
350         }
352         for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
354             /* Transform the requested snap point to this item's coordinates */
355             Geom::Matrix i2doc(Geom::identity());
356             SPItem *root_item = NULL;
357             /* We might have a clone at hand, so make sure we get the root item */
358             if (SP_IS_USE((*i).item)) {
359                 i2doc = sp_use_get_root_transform(SP_USE((*i).item));
360                 root_item = sp_use_root(SP_USE((*i).item));
361                 g_return_if_fail(root_item);
362             } else {
363                 i2doc = sp_item_i2doc_affine((*i).item);
364                 root_item = (*i).item;
365             }
367             //Build a list of all paths considered for snapping to
369             //Add the item's path to snap to
370             if (_snapmanager->snapprefs.getSnapToItemPath()) {
371                 if (!(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node)) {
372                     // Snapping to the path of characters is very cool, but for a large
373                     // chunk of text this will take ages! So limit snapping to text paths
374                     // containing max. 240 characters. Snapping the bbox will not be affected
375                     bool very_lenghty_prose = false;
376                     if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
377                         very_lenghty_prose =  sp_text_get_length(SP_TEXT(root_item)) > 240;
378                     }
379                     // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
380                     // which corresponds to a lag of 500 msec. This is for snapping a rect
381                     // to a single line of text.
383                     // Snapping for example to a traced bitmap is also very stressing for
384                     // the CPU, so we'll only snap to paths having no more than 500 nodes
385                     // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
386                     bool very_complex_path = false;
387                     if (SP_IS_PATH(root_item)) {
388                         very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
389                     }
391                     if (!very_lenghty_prose && !very_complex_path) {
392                         SPCurve *curve = curve_for_item(root_item);
393                         if (curve) {
394                             // We will get our own copy of the path, which must be freed at some point
395                             Geom::PathVector *borderpathv = pathvector_for_curve(root_item, curve, true, true, Geom::identity(), (*i).additional_affine);
396                             _paths_to_snap_to->push_back(std::make_pair(borderpathv, SNAPTARGET_PATH)); // Perhaps for speed, get a reference to the Geom::pathvector, and store the transformation besides it.
397                             curve->unref();
398                         }
399                     }
400                 }
401             }
403             //Add the item's bounding box to snap to
404             if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
405                 if (!(_snapmanager->snapprefs.getStrictSnapping() && p_is_a_node)) {
406                     // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
407                     // of the item AND the bbox of the clipping path at the same time
408                     if (!(*i).clip_or_mask) {
409                         Geom::OptRect rect;
410                         sp_item_invoke_bbox(root_item, rect, i2doc, TRUE, bbox_type);
411                         if (rect) {
412                             Geom::PathVector *path = _getPathvFromRect(*rect);
413                             _paths_to_snap_to->push_back(std::make_pair(path, SNAPTARGET_BBOX_EDGE));
414                         }
415                     }
416                 }
417             }
418         }
419     }
422 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
423                                      Inkscape::SnapPreferences::PointType const &t,
424                                      Geom::Point const &p,
425                                      SnapSourceType const &source_type,
426                                      bool const &first_point,
427                                      std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
428                                      SPPath const *selected_path) const
430     _collectPaths(t, first_point);
431     // Now we can finally do the real snapping, using the paths collected above
433     g_assert(_snapmanager->getDesktop() != NULL);
434     Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p);
436     bool const node_tool_active = _snapmanager->snapprefs.getSnapToItemPath() && selected_path != NULL;
438     if (first_point) {
439         /* findCandidates() is used for snapping to both paths and nodes. It ignores the path that is
440          * currently being edited, because that path requires special care: when snapping to nodes
441          * only the unselected nodes of that path should be considered, and these will be passed on separately.
442          * This path must not be ignored however when snapping to the paths, so we add it here
443          * manually when applicable.
444          *
445          * Note that this path must be the last in line!
446          * */
447         if (node_tool_active) {
448             SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
449             if (curve) {
450                 Geom::PathVector *pathv = pathvector_for_curve(SP_ITEM(selected_path), curve, true, true, Geom::identity(), Geom::identity()); // We will get our own copy of the path, which must be freed at some point
451                 _paths_to_snap_to->push_back(std::make_pair(pathv, SNAPTARGET_PATH));
452                 curve->unref();
453             }
454         }
455     }
457     for (std::vector<std::pair<Geom::PathVector*, SnapTargetType> >::const_iterator it_p = _paths_to_snap_to->begin(); it_p != _paths_to_snap_to->end(); it_p++) {
458         bool const being_edited = (node_tool_active && (*it_p) == _paths_to_snap_to->back());
459         //if true then this pathvector it_pv is currently being edited in the node tool
461         // char * svgd = sp_svg_write_path(**it_p->first);
462         // std::cout << "Dumping the pathvector: " << svgd << std::endl;
464         for(Geom::PathVector::iterator it_pv = (it_p->first)->begin(); it_pv != (it_p->first)->end(); ++it_pv) {
465             // Find a nearest point for each curve within this path
466             // n curves will return n time values with 0 <= t <= 1
467             std::vector<double> anp = (*it_pv).nearestPointPerCurve(p_doc);
469             std::vector<double>::const_iterator np = anp.begin();
470             unsigned int index = 0;
471             for (; np != anp.end(); np++, index++) {
472                 Geom::Curve const *curve = &((*it_pv).at_index(index));
473                 Geom::Point const sp_doc = curve->pointAt(*np);
475                 bool c1 = true;
476                 bool c2 = true;
477                 if (being_edited) {
478                     /* If the path is being edited, then we should only snap though to stationary pieces of the path
479                      * and not to the pieces that are being dragged around. This way we avoid
480                      * self-snapping. For this we check whether the nodes at both ends of the current
481                      * piece are unselected; if they are then this piece must be stationary
482                      */
483                     g_assert(unselected_nodes != NULL);
484                     Geom::Point start_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(0));
485                     Geom::Point end_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(1));
486                     c1 = isUnselectedNode(start_pt, unselected_nodes);
487                     c2 = isUnselectedNode(end_pt, unselected_nodes);
488                     /* Unfortunately, this might yield false positives for coincident nodes. Inkscape might therefore mistakenly
489                      * snap to path segments that are not stationary. There are at least two possible ways to overcome this:
490                      * - Linking the individual nodes of the SPPath we have here, to the nodes of the NodePath::SubPath class as being
491                      *   used in sp_nodepath_selected_nodes_move. This class has a member variable called "selected". For this the nodes
492                      *   should be in the exact same order for both classes, so we can index them
493                      * - Replacing the SPPath being used here by the the NodePath::SubPath class; but how?
494                      */
495                 }
497                 Geom::Point const sp_dt = _snapmanager->getDesktop()->doc2dt(sp_doc);
498                 if (!being_edited || (c1 && c2)) {
499                     Geom::Coord const dist = Geom::distance(sp_doc, p_doc);
500                     if (dist < getSnapperTolerance()) {
501                         sc.curves.push_back(Inkscape::SnappedCurve(sp_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), false, curve, source_type, it_p->second));
502                     }
503                 }
504             }
505         } // End of: for (Geom::PathVector::iterator ....)
506     }
509 /* Returns true if point is coincident with one of the unselected nodes */
510 bool Inkscape::ObjectSnapper::isUnselectedNode(Geom::Point const &point, std::vector<std::pair<Geom::Point, int> > const *unselected_nodes) const
512     if (unselected_nodes == NULL) {
513         return false;
514     }
516     if (unselected_nodes->size() == 0) {
517         return false;
518     }
520     for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
521         if (Geom::L2(point - (*i).first) < 1e-4) {
522             return true;
523         }
524     }
526     return false;
529 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
530                                      Inkscape::SnapPreferences::PointType const &t,
531                                      Geom::Point const &p,
532                                      SnapSourceType const source_type,
533                                      bool const &first_point,
534                                      ConstraintLine const &c) const
537     _collectPaths(t, first_point);
539     // Now we can finally do the real snapping, using the paths collected above
541     g_assert(_snapmanager->getDesktop() != NULL);
542     Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p);
544     Geom::Point direction_vector = c.getDirection();
545     if (!is_zero(direction_vector)) {
546         direction_vector = Geom::unit_vector(direction_vector);
547     }
549     Geom::Point const p1_on_cl = c.hasPoint() ? c.getPoint() : p;
550     Geom::Point const p2_on_cl = p1_on_cl + direction_vector;
552     // The intersection point of the constraint line with any path,
553     // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
554     // The distance between those points is twice the snapping tolerance
555     Geom::Point const p_proj_on_cl = project_on_linesegment(p, p1_on_cl, p2_on_cl);
556     Geom::Point const p_min_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
557     Geom::Point const p_max_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
559     Geom::Path cl;
560     std::vector<Geom::Path> clv;
561     cl.start(p_min_on_cl);
562     cl.appendNew<Geom::LineSegment>(p_max_on_cl);
563     clv.push_back(cl);
565     for (std::vector<std::pair<Geom::PathVector*, SnapTargetType> >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
566         if (k->first) {
567             Geom::CrossingSet cs = Geom::crossings(clv, *(k->first));
568             if (cs.size() > 0) {
569                 // We need only the first element of cs, because cl is only a single straight linesegment
570                 // This first element contains a vector filled with crossings of cl with k->first
571                 for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
572                     if ((*m).ta >= 0 && (*m).ta <= 1 ) {
573                         // Reconstruct the point of intersection
574                         Geom::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
575                         // When it's within snapping range, then return it
576                         // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
577                         Geom::Coord dist = Geom::L2(_snapmanager->getDesktop()->dt2doc(p_proj_on_cl) - p_inters);
578                         SnappedPoint s(_snapmanager->getDesktop()->doc2dt(p_inters), source_type, k->second, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
579                         sc.points.push_back(s);
580                     }
581                 }
582             }
583         }
584     }
588 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
589                                             Inkscape::SnapPreferences::PointType const &t,
590                                             Geom::Point const &p,
591                                             SnapSourceType const &source_type,
592                                             bool const &first_point,
593                                             Geom::OptRect const &bbox_to_snap,
594                                             std::vector<SPItem const *> const *it,
595                                             std::vector<std::pair<Geom::Point, int> > *unselected_nodes) const
597     if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false ) {
598         return;
599     }
601     /* Get a list of all the SPItems that we will try to snap to */
602     if (first_point) {
603         Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
604         _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
605     }
607     if (_snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapSmoothNodes()
608         || _snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapToPageBorder()
609                 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
610                 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
611                 || _snapmanager->snapprefs.getIncludeItemCenter()) {
612         _snapNodes(sc, t, p, source_type, first_point, unselected_nodes);
613     }
615     if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
616         unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
617         if (n > 0) {
618             /* While editing a path in the node tool, findCandidates must ignore that path because
619              * of the node snapping requirements (i.e. only unselected nodes must be snapable).
620              * That path must not be ignored however when snapping to the paths, so we add it here
621              * manually when applicable
622              */
623             SPPath *path = NULL;
624             if (it != NULL) {
625                 g_assert(SP_IS_PATH(*it->begin()));
626                 g_assert(it->size() == 1);
627                 path = SP_PATH(*it->begin());
628             }
629             _snapPaths(sc, t, p, source_type, first_point, unselected_nodes, path);
630         } else {
631             _snapPaths(sc, t, p, source_type, first_point, NULL, NULL);
632         }
633     }
636 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
637                                                   Inkscape::SnapPreferences::PointType const &t,
638                                                   Geom::Point const &p,
639                                                   SnapSourceType const &source_type,
640                                                   bool const &first_point,
641                                                   Geom::OptRect const &bbox_to_snap,
642                                                   ConstraintLine const &c,
643                                                   std::vector<SPItem const *> const *it) const
645     if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false) {
646         return;
647     }
649     /* Get a list of all the SPItems that we will try to snap to */
650     if (first_point) {
651         Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
652         _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
653     }
655     // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
656     // This is useful for example when scaling an object while maintaining a fixed aspect ratio. It's
657     // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
659     // When snapping to objects, we either snap to their nodes or their paths. It is however very
660     // unlikely that any node will be exactly at the constrained line, so for a constrained snap
661     // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
662     // so we will more or less snap to them anyhow.
664     if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
665         _snapPathsConstrained(sc, t, p, source_type, first_point, c);
666     }
670 // This method is used to snap a guide to nodes, while dragging the guide around
671 void Inkscape::ObjectSnapper::guideSnap(SnappedConstraints &sc,
672                                         Geom::Point const &p,
673                                         Geom::Point const &guide_normal) const
675     /* Get a list of all the SPItems that we will try to snap to */
676     std::vector<SPItem*> cand;
677     std::vector<SPItem const *> const it; //just an empty list
679     DimensionToSnap snap_dim;
680     if (guide_normal == to_2geom(component_vectors[Geom::Y])) {
681         snap_dim = GUIDE_TRANSL_SNAP_Y;
682     } else if (guide_normal == to_2geom(component_vectors[Geom::X])) {
683         snap_dim = GUIDE_TRANSL_SNAP_X;
684     } else {
685         snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
686     }
688     // We don't support ANGLED_GUIDE_ROT_SNAP yet.
690     // It would be cool to allow the user to rotate a guide by dragging it, instead of
691     // only translating it. (For example when CTRL is pressed). We will need an UI part
692     // for that first; and some important usability choices need to be made:
693     // E.g. which point should be used for pivoting? A previously snapped point,
694     // or a transformation center (which can be moved after clicking for the
695     // second time on an object; but should this point then be constrained to the
696     // line, or can it be located anywhere?)
698     _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), snap_dim, false, Geom::identity());
699     _snapTranslatingGuideToNodes(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, guide_normal);
700     // _snapRotatingGuideToNodes has not been implemented yet.
703 /**
704  *  \return true if this Snapper will snap at least one kind of point.
705  */
706 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
708     bool snap_to_something = _snapmanager->snapprefs.getSnapToItemPath()
709                                                 || _snapmanager->snapprefs.getSnapToItemNode()
710                                                 || _snapmanager->snapprefs.getSnapToBBoxPath()
711                                                 || _snapmanager->snapprefs.getSnapToBBoxNode()
712                                                 || _snapmanager->snapprefs.getSnapToPageBorder()
713                                                 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
714                                                 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
715                                                 || _snapmanager->snapprefs.getIncludeItemCenter();
717     return (_snap_enabled && _snapmanager->snapprefs.getSnapModeBBoxOrNodes() && snap_to_something);
720 bool Inkscape::ObjectSnapper::GuidesMightSnap() const
722     bool snap_to_something = _snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapToBBoxNode();
723     return (_snap_enabled && _snapmanager->snapprefs.getSnapModeGuide() && snap_to_something);
726 void Inkscape::ObjectSnapper::_clear_paths() const
728     for (std::vector<std::pair<Geom::PathVector*, SnapTargetType> >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
729         g_free(k->first);
730     }
731     _paths_to_snap_to->clear();
734 Geom::PathVector* Inkscape::ObjectSnapper::_getBorderPathv() const
736     Geom::Rect const border_rect = Geom::Rect(Geom::Point(0,0), Geom::Point(sp_document_width(_snapmanager->getDocument()),sp_document_height(_snapmanager->getDocument())));
737     return _getPathvFromRect(border_rect);
740 Geom::PathVector* Inkscape::ObjectSnapper::_getPathvFromRect(Geom::Rect const rect) const
742     SPCurve const *border_curve = SPCurve::new_from_rect(rect);
743     if (border_curve) {
744         Geom::PathVector *dummy = new Geom::PathVector(border_curve->get_pathvector());
745         return dummy;
746     } else {
747         return NULL;
748     }
751 void Inkscape::ObjectSnapper::_getBorderNodes(std::vector<std::pair<Geom::Point, int> > *points) const
753     Geom::Coord w = sp_document_width(_snapmanager->getDocument());
754     Geom::Coord h = sp_document_height(_snapmanager->getDocument());
755     points->push_back(std::make_pair(Geom::Point(0,0), SNAPTARGET_PAGE_CORNER));
756     points->push_back(std::make_pair(Geom::Point(0,h), SNAPTARGET_PAGE_CORNER));
757     points->push_back(std::make_pair(Geom::Point(w,h), SNAPTARGET_PAGE_CORNER));
758     points->push_back(std::make_pair(Geom::Point(w,0), SNAPTARGET_PAGE_CORNER));
761 void Inkscape::getBBoxPoints(Geom::OptRect const bbox, std::vector<std::pair<Geom::Point, int> > *points, bool const isTarget, bool const includeCorners, bool const includeLineMidpoints, bool const includeObjectMidpoints)
763         if (bbox) {
764                 // collect the corners of the bounding box
765                 for ( unsigned k = 0 ; k < 4 ; k++ ) {
766                         if (includeCorners) {
767                                 points->push_back(std::make_pair((bbox->corner(k)), isTarget ? int(Inkscape::SNAPTARGET_BBOX_CORNER) : int(Inkscape::SNAPSOURCE_BBOX_CORNER)));
768                         }
769                         // optionally, collect the midpoints of the bounding box's edges too
770                         if (includeLineMidpoints) {
771                                 points->push_back(std::make_pair((bbox->corner(k) + bbox->corner((k+1) % 4))/2, isTarget ? int(Inkscape::SNAPTARGET_BBOX_EDGE_MIDPOINT) : int(Inkscape::SNAPSOURCE_BBOX_EDGE_MIDPOINT)));
772                         }
773                 }
774                 if (includeObjectMidpoints) {
775                         points->push_back(std::make_pair(bbox->midpoint(), isTarget ? int(Inkscape::SNAPTARGET_BBOX_MIDPOINT) : int(Inkscape::SNAPSOURCE_BBOX_MIDPOINT)));
776                 }
777         }
780 /*
781   Local Variables:
782   mode:c++
783   c-file-style:"stroustrup"
784   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
785   indent-tabs-mode:nil
786   fill-column:99
787   End:
788 */
789 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :