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 <2geom/path-intersection.h>
16 #include <2geom/point.h>
17 #include <2geom/rect.h>
18 #include <2geom/line.h>
19 #include "document.h"
20 #include "sp-namedview.h"
21 #include "sp-image.h"
22 #include "sp-item-group.h"
23 #include "sp-item.h"
24 #include "sp-use.h"
25 #include "display/curve.h"
26 #include "inkscape.h"
27 #include "preferences.h"
28 #include "sp-text.h"
29 #include "sp-flowtext.h"
30 #include "text-editing.h"
31 #include "sp-clippath.h"
32 #include "sp-mask.h"
33 #include "helper/geom-curves.h"
34 #include "desktop.h"
36 Inkscape::SnapCandidate::SnapCandidate(SPItem* item, bool clip_or_mask, Geom::Matrix additional_affine)
37 : item(item), clip_or_mask(clip_or_mask), additional_affine(additional_affine)
38 {
39 }
41 Inkscape::SnapCandidate::~SnapCandidate()
42 {
43 }
45 Inkscape::ObjectSnapper::ObjectSnapper(SnapManager *sm, Geom::Coord const d)
46 : Snapper(sm, d)
47 {
48 _candidates = new std::vector<SnapCandidate>;
49 _points_to_snap_to = new std::vector<std::pair<Geom::Point, int> >;
50 _paths_to_snap_to = new std::vector<std::pair<Geom::PathVector*, SnapTargetType> >;
51 }
53 Inkscape::ObjectSnapper::~ObjectSnapper()
54 {
55 _candidates->clear();
56 delete _candidates;
58 _points_to_snap_to->clear();
59 delete _points_to_snap_to;
61 _clear_paths();
62 delete _paths_to_snap_to;
63 }
65 /**
66 * \return Snap tolerance (desktop coordinates); depends on current zoom so that it's always the same in screen pixels
67 */
68 Geom::Coord Inkscape::ObjectSnapper::getSnapperTolerance() const
69 {
70 SPDesktop const *dt = _snapmanager->getDesktop();
71 double const zoom = dt ? dt->current_zoom() : 1;
72 return _snapmanager->snapprefs.getObjectTolerance() / zoom;
73 }
75 bool Inkscape::ObjectSnapper::getSnapperAlwaysSnap() const
76 {
77 return _snapmanager->snapprefs.getObjectTolerance() == 10000; //TODO: Replace this threshold of 10000 by a constant; see also tolerance-slider.cpp
78 }
80 /**
81 * Find all items within snapping range.
82 * \param parent Pointer to the document's root, or to a clipped path or mask object
83 * \param it List of items to ignore
84 * \param first_point If true then this point is the first one from a whole bunch of points
85 * \param bbox_to_snap Bounding box hulling the whole bunch of points, all from the same selection and having the same transformation
86 * \param DimensionToSnap Snap in X, Y, or both directions.
87 */
89 void Inkscape::ObjectSnapper::_findCandidates(SPObject* parent,
90 std::vector<SPItem const *> const *it,
91 bool const &first_point,
92 Geom::Rect const &bbox_to_snap,
93 DimensionToSnap const snap_dim,
94 bool const clip_or_mask,
95 Geom::Matrix const additional_affine) const // transformation of the item being clipped / masked
96 {
97 bool const c1 = (snap_dim == TRANSL_SNAP_XY) && ThisSnapperMightSnap();
98 bool const c2 = (snap_dim != TRANSL_SNAP_XY) && GuidesMightSnap();
100 if (!(c1 || c2)) {
101 return;
102 }
104 if (first_point) {
105 _candidates->clear();
106 }
108 Geom::Rect bbox_to_snap_incl = bbox_to_snap; // _incl means: will include the snapper tolerance
109 bbox_to_snap_incl.expandBy(getSnapperTolerance()); // see?
111 for (SPObject* o = sp_object_first_child(parent); o != NULL; o = SP_OBJECT_NEXT(o)) {
112 g_assert(_snapmanager->getDesktop() != NULL);
113 if (SP_IS_ITEM(o) && !(_snapmanager->getDesktop()->itemIsHidden(SP_ITEM(o)) && !clip_or_mask)) {
114 // Snapping to items in a locked layer is allowed
115 // Don't snap to hidden objects, unless they're a clipped path or a mask
116 /* See if this item is on the ignore list */
117 std::vector<SPItem const *>::const_iterator i;
118 if (it != NULL) {
119 i = it->begin();
120 while (i != it->end() && *i != o) {
121 i++;
122 }
123 }
125 if (it == NULL || i == it->end()) {
126 SPItem *item = SP_ITEM(o);
127 if (item) {
128 SPObject *obj = NULL;
129 if (!clip_or_mask) { // cannot clip or mask more than once
130 // The current item is not a clipping path or a mask, but might
131 // still be the subject of clipping or masking itself ; if so, then
132 // we should also consider that path or mask for snapping to
133 obj = SP_OBJECT(item->clip_ref->getObject());
134 if (obj) {
135 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
136 }
137 obj = SP_OBJECT(item->mask_ref->getObject());
138 if (obj) {
139 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
140 }
141 }
142 }
144 if (SP_IS_GROUP(o)) {
145 _findCandidates(o, it, false, bbox_to_snap, snap_dim, clip_or_mask, additional_affine);
146 } else {
147 Geom::OptRect bbox_of_item = Geom::Rect();
148 if (clip_or_mask) {
149 // Oh oh, this will get ugly. We cannot use sp_item_i2d_affine directly because we need to
150 // insert an additional transformation in document coordinates (code copied from sp_item_i2d_affine)
151 sp_item_invoke_bbox(item,
152 bbox_of_item,
153 sp_item_i2doc_affine(item) * additional_affine * _snapmanager->getDesktop()->doc2dt(),
154 true);
155 } else {
156 sp_item_invoke_bbox(item, bbox_of_item, sp_item_i2d_affine(item), true);
157 }
158 if (bbox_of_item) {
159 // See if the item is within range
160 if (bbox_to_snap_incl.intersects(*bbox_of_item)) {
161 // This item is within snapping range, so record it as a candidate
162 _candidates->push_back(SnapCandidate(item, clip_or_mask, additional_affine));
163 // For debugging: print the id of the candidate to the console
164 // SPObject *obj = (SPObject*)item;
165 // std::cout << "Snap candidate added: " << obj->id << std::endl;
166 }
167 }
168 }
169 }
170 }
171 }
172 }
175 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::SnapPreferences::PointType const &t,
176 bool const &first_point) const
177 {
178 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
179 // e.g. when translating an item using the selector tool, then we will only do this for the
180 // first point and store the collection for later use. This significantly improves the performance
181 if (first_point) {
182 _points_to_snap_to->clear();
184 // Determine the type of bounding box we should snap to
185 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
187 bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
188 bool p_is_a_bbox = t & Inkscape::SnapPreferences::SNAPPOINT_BBOX;
189 bool p_is_a_guide = t & Inkscape::SnapPreferences::SNAPPOINT_GUIDE;
191 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
192 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)));
194 if (_snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()) {
195 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
196 bool prefs_bbox = prefs->getBool("/tools/bounding_box");
197 bbox_type = !prefs_bbox ?
198 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
199 }
201 // Consider the page border for snapping to
202 if (_snapmanager->snapprefs.getSnapToPageBorder()) {
203 _getBorderNodes(_points_to_snap_to);
204 }
206 for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
207 //Geom::Matrix i2doc(Geom::identity());
208 SPItem *root_item = (*i).item;
209 if (SP_IS_USE((*i).item)) {
210 root_item = sp_use_root(SP_USE((*i).item));
211 }
212 g_return_if_fail(root_item);
214 //Collect all nodes so we can snap to them
215 if (p_is_a_node || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node) || p_is_a_guide) {
216 // Note: there are two ways in which intersections are considered:
217 // Method 1: Intersections are calculated for each shape individually, for both the
218 // snap source and snap target (see sp_shape_snappoints)
219 // Method 2: Intersections are calculated for each curve or line that we've snapped to, i.e. only for
220 // the target (see the intersect() method in the SnappedCurve and SnappedLine classes)
221 // Some differences:
222 // - Method 1 doesn't find intersections within a set of multiple objects
223 // - Method 2 only works for targets
224 // When considering intersections as snap targets:
225 // - Method 1 only works when snapping to nodes, whereas
226 // - Method 2 only works when snapping to paths
227 // - There will be performance differences too!
228 // If both methods are being used simultaneously, then this might lead to duplicate targets!
230 // Well, here we will be looking for snap TARGETS. Both methods can therefore be used.
231 // When snapping to paths, we will get a collection of snapped lines and snapped curves. findBestSnap() will
232 // go hunting for intersections (but only when asked to in the prefs of course). In that case we can just
233 // temporarily block the intersections in sp_item_snappoints, we don't need duplicates. If we're not snapping to
234 // paths though but only to item nodes then we should still look for the intersections in sp_item_snappoints()
235 bool old_pref = _snapmanager->snapprefs.getSnapIntersectionCS();
236 if (_snapmanager->snapprefs.getSnapToItemPath()) {
237 _snapmanager->snapprefs.setSnapIntersectionCS(false);
238 }
240 sp_item_snappoints(root_item, true, *_points_to_snap_to, &_snapmanager->snapprefs);
242 if (_snapmanager->snapprefs.getSnapToItemPath()) {
243 _snapmanager->snapprefs.setSnapIntersectionCS(old_pref);
244 }
245 }
247 //Collect the bounding box's corners so we can snap to them
248 if (p_is_a_bbox || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_bbox) || p_is_a_guide) {
249 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
250 // of the item AND the bbox of the clipping path at the same time
251 if (!(*i).clip_or_mask) {
252 Geom::OptRect b = sp_item_bbox_desktop(root_item, bbox_type);
253 getBBoxPoints(b, _points_to_snap_to, true, _snapmanager->snapprefs.getSnapToBBoxNode(), _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints(), _snapmanager->snapprefs.getSnapBBoxMidpoints());
254 }
255 }
256 }
257 }
258 }
260 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
261 Inkscape::SnapPreferences::PointType const &t,
262 Geom::Point const &p,
263 SnapSourceType const &source_type,
264 bool const &first_point,
265 std::vector<std::pair<Geom::Point, int> > *unselected_nodes) const
266 {
267 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
269 _collectNodes(t, first_point);
271 if (unselected_nodes != NULL) {
272 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
273 }
275 SnappedPoint s;
276 bool success = false;
278 for (std::vector<std::pair<Geom::Point, int> >::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
279 Geom::Coord dist = Geom::L2((*k).first - p);
280 if (dist < getSnapperTolerance() && dist < s.getSnapDistance()) {
281 s = SnappedPoint((*k).first, source_type, static_cast<Inkscape::SnapTargetType>((*k).second), dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
282 success = true;
283 }
284 }
286 if (success) {
287 sc.points.push_back(s);
288 }
289 }
291 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
292 Inkscape::SnapPreferences::PointType const &t,
293 Geom::Point const &p,
294 Geom::Point const &guide_normal) const
295 {
296 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
297 _collectNodes(t, true);
299 SnappedPoint s;
300 bool success = false;
302 Geom::Coord tol = getSnapperTolerance();
304 for (std::vector<std::pair<Geom::Point, int> >::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
305 // Project each node (*k) on the guide line (running through point p)
306 Geom::Point p_proj = Geom::projection((*k).first, Geom::Line(p, p + Geom::rot90(guide_normal)));
307 Geom::Coord dist = Geom::L2((*k).first - p_proj); // distance from node to the guide
308 Geom::Coord dist2 = Geom::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
309 if ((dist < tol && dist2 < tol) || (getSnapperAlwaysSnap() && dist < s.getSnapDistance())) {
310 s = SnappedPoint((*k).first, SNAPSOURCE_GUIDE, static_cast<Inkscape::SnapTargetType>((*k).second), dist, tol, getSnapperAlwaysSnap(), true);
311 success = true;
312 }
313 }
315 if (success) {
316 sc.points.push_back(s);
317 }
318 }
321 /**
322 * Returns index of first NR_END bpath in array.
323 */
325 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::SnapPreferences::PointType const &t,
326 bool const &first_point) const
327 {
328 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
329 // e.g. when translating an item using the selector tool, then we will only do this for the
330 // first point and store the collection for later use. This significantly improves the performance
331 if (first_point) {
332 _clear_paths();
334 // Determine the type of bounding box we should snap to
335 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
337 bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
339 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
340 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
341 int prefs_bbox = prefs->getBool("/tools/bounding_box", 0);
342 bbox_type = !prefs_bbox ?
343 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
344 }
346 // Consider the page border for snapping
347 if (_snapmanager->snapprefs.getSnapToPageBorder()) {
348 Geom::PathVector *border_path = _getBorderPathv();
349 if (border_path != NULL) {
350 _paths_to_snap_to->push_back(std::make_pair(border_path, SNAPTARGET_PAGE_BORDER));
351 }
352 }
354 for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
356 /* Transform the requested snap point to this item's coordinates */
357 Geom::Matrix i2doc(Geom::identity());
358 SPItem *root_item = NULL;
359 /* We might have a clone at hand, so make sure we get the root item */
360 if (SP_IS_USE((*i).item)) {
361 i2doc = sp_use_get_root_transform(SP_USE((*i).item));
362 root_item = sp_use_root(SP_USE((*i).item));
363 g_return_if_fail(root_item);
364 } else {
365 i2doc = sp_item_i2doc_affine((*i).item);
366 root_item = (*i).item;
367 }
369 //Build a list of all paths considered for snapping to
371 //Add the item's path to snap to
372 if (_snapmanager->snapprefs.getSnapToItemPath()) {
373 if (!(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node)) {
374 // Snapping to the path of characters is very cool, but for a large
375 // chunk of text this will take ages! So limit snapping to text paths
376 // containing max. 240 characters. Snapping the bbox will not be affected
377 bool very_lenghty_prose = false;
378 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
379 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
380 }
381 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
382 // which corresponds to a lag of 500 msec. This is for snapping a rect
383 // to a single line of text.
385 // Snapping for example to a traced bitmap is also very stressing for
386 // the CPU, so we'll only snap to paths having no more than 500 nodes
387 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
388 bool very_complex_path = false;
389 if (SP_IS_PATH(root_item)) {
390 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
391 }
393 if (!very_lenghty_prose && !very_complex_path) {
394 SPCurve *curve = curve_for_item(root_item);
395 if (curve) {
396 // We will get our own copy of the path, which must be freed at some point
397 Geom::PathVector *borderpathv = pathvector_for_curve(root_item, curve, true, true, Geom::identity(), (*i).additional_affine);
398 _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.
399 curve->unref();
400 }
401 }
402 }
403 }
405 //Add the item's bounding box to snap to
406 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
407 if (!(_snapmanager->snapprefs.getStrictSnapping() && p_is_a_node)) {
408 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
409 // of the item AND the bbox of the clipping path at the same time
410 if (!(*i).clip_or_mask) {
411 Geom::OptRect rect;
412 sp_item_invoke_bbox(root_item, rect, i2doc, TRUE, bbox_type);
413 if (rect) {
414 Geom::PathVector *path = _getPathvFromRect(*rect);
415 _paths_to_snap_to->push_back(std::make_pair(path, SNAPTARGET_BBOX_EDGE));
416 }
417 }
418 }
419 }
420 }
421 }
422 }
424 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
425 Inkscape::SnapPreferences::PointType const &t,
426 Geom::Point const &p,
427 SnapSourceType const &source_type,
428 bool const &first_point,
429 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
430 SPPath const *selected_path) const
431 {
432 _collectPaths(t, first_point);
433 // Now we can finally do the real snapping, using the paths collected above
435 g_assert(_snapmanager->getDesktop() != NULL);
436 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p);
438 bool const node_tool_active = _snapmanager->snapprefs.getSnapToItemPath() && selected_path != NULL;
440 if (first_point) {
441 /* findCandidates() is used for snapping to both paths and nodes. It ignores the path that is
442 * currently being edited, because that path requires special care: when snapping to nodes
443 * only the unselected nodes of that path should be considered, and these will be passed on separately.
444 * This path must not be ignored however when snapping to the paths, so we add it here
445 * manually when applicable.
446 *
447 * Note that this path must be the last in line!
448 * */
449 if (node_tool_active) {
450 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
451 if (curve) {
452 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
453 _paths_to_snap_to->push_back(std::make_pair(pathv, SNAPTARGET_PATH));
454 curve->unref();
455 }
456 }
457 }
459 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++) {
460 bool const being_edited = (node_tool_active && (*it_p) == _paths_to_snap_to->back());
461 //if true then this pathvector it_pv is currently being edited in the node tool
463 // char * svgd = sp_svg_write_path(**it_p->first);
464 // std::cout << "Dumping the pathvector: " << svgd << std::endl;
466 for(Geom::PathVector::iterator it_pv = (it_p->first)->begin(); it_pv != (it_p->first)->end(); ++it_pv) {
467 // Find a nearest point for each curve within this path
468 // n curves will return n time values with 0 <= t <= 1
469 std::vector<double> anp = (*it_pv).nearestPointPerCurve(p_doc);
471 std::vector<double>::const_iterator np = anp.begin();
472 unsigned int index = 0;
473 for (; np != anp.end(); np++, index++) {
474 Geom::Curve const *curve = &((*it_pv).at_index(index));
475 Geom::Point const sp_doc = curve->pointAt(*np);
477 bool c1 = true;
478 bool c2 = true;
479 if (being_edited) {
480 /* If the path is being edited, then we should only snap though to stationary pieces of the path
481 * and not to the pieces that are being dragged around. This way we avoid
482 * self-snapping. For this we check whether the nodes at both ends of the current
483 * piece are unselected; if they are then this piece must be stationary
484 */
485 g_assert(unselected_nodes != NULL);
486 Geom::Point start_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(0));
487 Geom::Point end_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(1));
488 c1 = isUnselectedNode(start_pt, unselected_nodes);
489 c2 = isUnselectedNode(end_pt, unselected_nodes);
490 /* Unfortunately, this might yield false positives for coincident nodes. Inkscape might therefore mistakenly
491 * snap to path segments that are not stationary. There are at least two possible ways to overcome this:
492 * - Linking the individual nodes of the SPPath we have here, to the nodes of the NodePath::SubPath class as being
493 * used in sp_nodepath_selected_nodes_move. This class has a member variable called "selected". For this the nodes
494 * should be in the exact same order for both classes, so we can index them
495 * - Replacing the SPPath being used here by the the NodePath::SubPath class; but how?
496 */
497 }
499 Geom::Point const sp_dt = _snapmanager->getDesktop()->doc2dt(sp_doc);
500 if (!being_edited || (c1 && c2)) {
501 Geom::Coord const dist = Geom::distance(sp_doc, p_doc);
502 if (dist < getSnapperTolerance()) {
503 sc.curves.push_back(Inkscape::SnappedCurve(sp_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), false, curve, source_type, it_p->second));
504 }
505 }
506 }
507 } // End of: for (Geom::PathVector::iterator ....)
508 }
509 }
511 /* Returns true if point is coincident with one of the unselected nodes */
512 bool Inkscape::ObjectSnapper::isUnselectedNode(Geom::Point const &point, std::vector<std::pair<Geom::Point, int> > const *unselected_nodes) const
513 {
514 if (unselected_nodes == NULL) {
515 return false;
516 }
518 if (unselected_nodes->size() == 0) {
519 return false;
520 }
522 for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
523 if (Geom::L2(point - (*i).first) < 1e-4) {
524 return true;
525 }
526 }
528 return false;
529 }
531 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
532 Inkscape::SnapPreferences::PointType const &t,
533 Geom::Point const &p,
534 SnapSourceType const source_type,
535 bool const &first_point,
536 ConstraintLine const &c) const
537 {
539 _collectPaths(t, first_point);
541 // Now we can finally do the real snapping, using the paths collected above
543 g_assert(_snapmanager->getDesktop() != NULL);
544 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p);
546 Geom::Point direction_vector = c.getDirection();
547 if (!is_zero(direction_vector)) {
548 direction_vector = Geom::unit_vector(direction_vector);
549 }
551 // The intersection point of the constraint line with any path,
552 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
553 // The distance between those points is twice the snapping tolerance
554 Geom::Point const p_proj_on_cl = c.projection(p);
555 Geom::Point const p_min_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
556 Geom::Point const p_max_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
558 Geom::Path cl;
559 std::vector<Geom::Path> clv;
560 cl.start(p_min_on_cl);
561 cl.appendNew<Geom::LineSegment>(p_max_on_cl);
562 clv.push_back(cl);
564 for (std::vector<std::pair<Geom::PathVector*, SnapTargetType> >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
565 if (k->first) {
566 Geom::CrossingSet cs = Geom::crossings(clv, *(k->first));
567 if (cs.size() > 0) {
568 // We need only the first element of cs, because cl is only a single straight linesegment
569 // This first element contains a vector filled with crossings of cl with k->first
570 for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
571 if ((*m).ta >= 0 && (*m).ta <= 1 ) {
572 // Reconstruct the point of intersection
573 Geom::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
574 // When it's within snapping range, then return it
575 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
576 Geom::Coord dist = Geom::L2(_snapmanager->getDesktop()->dt2doc(p_proj_on_cl) - p_inters);
577 SnappedPoint s(_snapmanager->getDesktop()->doc2dt(p_inters), source_type, k->second, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
578 sc.points.push_back(s);
579 }
580 }
581 }
582 }
583 }
584 }
587 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
588 Inkscape::SnapPreferences::PointType const &t,
589 Geom::Point const &p,
590 SnapSourceType const &source_type,
591 bool const &first_point,
592 Geom::OptRect const &bbox_to_snap,
593 std::vector<SPItem const *> const *it,
594 std::vector<std::pair<Geom::Point, int> > *unselected_nodes) const
595 {
596 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false ) {
597 return;
598 }
600 /* Get a list of all the SPItems that we will try to snap to */
601 if (first_point) {
602 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
603 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
604 }
606 if (_snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapSmoothNodes()
607 || _snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapToPageBorder()
608 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
609 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
610 || _snapmanager->snapprefs.getIncludeItemCenter()) {
611 _snapNodes(sc, t, p, source_type, first_point, unselected_nodes);
612 }
614 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
615 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
616 if (n > 0) {
617 /* While editing a path in the node tool, findCandidates must ignore that path because
618 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
619 * That path must not be ignored however when snapping to the paths, so we add it here
620 * manually when applicable
621 */
622 SPPath *path = NULL;
623 if (it != NULL) {
624 g_assert(SP_IS_PATH(*it->begin()));
625 g_assert(it->size() == 1);
626 path = SP_PATH(*it->begin());
627 }
628 _snapPaths(sc, t, p, source_type, first_point, unselected_nodes, path);
629 } else {
630 _snapPaths(sc, t, p, source_type, first_point, NULL, NULL);
631 }
632 }
633 }
635 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
636 Inkscape::SnapPreferences::PointType const &t,
637 Geom::Point const &p,
638 SnapSourceType const &source_type,
639 bool const &first_point,
640 Geom::OptRect const &bbox_to_snap,
641 ConstraintLine const &c,
642 std::vector<SPItem const *> const *it) const
643 {
644 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false) {
645 return;
646 }
648 /* Get a list of all the SPItems that we will try to snap to */
649 if (first_point) {
650 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
651 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
652 }
654 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
655 // This is useful for example when scaling an object while maintaining a fixed aspect ratio. It's
656 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
658 // When snapping to objects, we either snap to their nodes or their paths. It is however very
659 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
660 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
661 // so we will more or less snap to them anyhow.
663 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
664 _snapPathsConstrained(sc, t, p, source_type, first_point, c);
665 }
666 }
669 // This method is used to snap a guide to nodes, while dragging the guide around
670 void Inkscape::ObjectSnapper::guideSnap(SnappedConstraints &sc,
671 Geom::Point const &p,
672 Geom::Point const &guide_normal) const
673 {
674 /* Get a list of all the SPItems that we will try to snap to */
675 std::vector<SPItem*> cand;
676 std::vector<SPItem const *> const it; //just an empty list
678 DimensionToSnap snap_dim;
679 if (guide_normal == to_2geom(component_vectors[Geom::Y])) {
680 snap_dim = GUIDE_TRANSL_SNAP_Y;
681 } else if (guide_normal == to_2geom(component_vectors[Geom::X])) {
682 snap_dim = GUIDE_TRANSL_SNAP_X;
683 } else {
684 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
685 }
687 // We don't support ANGLED_GUIDE_ROT_SNAP yet.
689 // It would be cool to allow the user to rotate a guide by dragging it, instead of
690 // only translating it. (For example when CTRL is pressed). We will need an UI part
691 // for that first; and some important usability choices need to be made:
692 // E.g. which point should be used for pivoting? A previously snapped point,
693 // or a transformation center (which can be moved after clicking for the
694 // second time on an object; but should this point then be constrained to the
695 // line, or can it be located anywhere?)
697 _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), snap_dim, false, Geom::identity());
698 _snapTranslatingGuideToNodes(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, guide_normal);
699 // _snapRotatingGuideToNodes has not been implemented yet.
700 }
702 /**
703 * \return true if this Snapper will snap at least one kind of point.
704 */
705 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
706 {
707 bool snap_to_something = _snapmanager->snapprefs.getSnapToItemPath()
708 || _snapmanager->snapprefs.getSnapToItemNode()
709 || _snapmanager->snapprefs.getSnapToBBoxPath()
710 || _snapmanager->snapprefs.getSnapToBBoxNode()
711 || _snapmanager->snapprefs.getSnapToPageBorder()
712 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
713 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
714 || _snapmanager->snapprefs.getIncludeItemCenter();
716 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeBBoxOrNodes() && snap_to_something);
717 }
719 bool Inkscape::ObjectSnapper::GuidesMightSnap() const
720 {
721 bool snap_to_something = _snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapToBBoxNode();
722 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeGuide() && snap_to_something);
723 }
725 void Inkscape::ObjectSnapper::_clear_paths() const
726 {
727 for (std::vector<std::pair<Geom::PathVector*, SnapTargetType> >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
728 g_free(k->first);
729 }
730 _paths_to_snap_to->clear();
731 }
733 Geom::PathVector* Inkscape::ObjectSnapper::_getBorderPathv() const
734 {
735 Geom::Rect const border_rect = Geom::Rect(Geom::Point(0,0), Geom::Point(sp_document_width(_snapmanager->getDocument()),sp_document_height(_snapmanager->getDocument())));
736 return _getPathvFromRect(border_rect);
737 }
739 Geom::PathVector* Inkscape::ObjectSnapper::_getPathvFromRect(Geom::Rect const rect) const
740 {
741 SPCurve const *border_curve = SPCurve::new_from_rect(rect);
742 if (border_curve) {
743 Geom::PathVector *dummy = new Geom::PathVector(border_curve->get_pathvector());
744 return dummy;
745 } else {
746 return NULL;
747 }
748 }
750 void Inkscape::ObjectSnapper::_getBorderNodes(std::vector<std::pair<Geom::Point, int> > *points) const
751 {
752 Geom::Coord w = sp_document_width(_snapmanager->getDocument());
753 Geom::Coord h = sp_document_height(_snapmanager->getDocument());
754 points->push_back(std::make_pair(Geom::Point(0,0), SNAPTARGET_PAGE_CORNER));
755 points->push_back(std::make_pair(Geom::Point(0,h), SNAPTARGET_PAGE_CORNER));
756 points->push_back(std::make_pair(Geom::Point(w,h), SNAPTARGET_PAGE_CORNER));
757 points->push_back(std::make_pair(Geom::Point(w,0), SNAPTARGET_PAGE_CORNER));
758 }
760 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)
761 {
762 if (bbox) {
763 // collect the corners of the bounding box
764 for ( unsigned k = 0 ; k < 4 ; k++ ) {
765 if (includeCorners) {
766 points->push_back(std::make_pair((bbox->corner(k)), isTarget ? int(Inkscape::SNAPTARGET_BBOX_CORNER) : int(Inkscape::SNAPSOURCE_BBOX_CORNER)));
767 }
768 // optionally, collect the midpoints of the bounding box's edges too
769 if (includeLineMidpoints) {
770 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)));
771 }
772 }
773 if (includeObjectMidpoints) {
774 points->push_back(std::make_pair(bbox->midpoint(), isTarget ? int(Inkscape::SNAPTARGET_BBOX_MIDPOINT) : int(Inkscape::SNAPSOURCE_BBOX_MIDPOINT)));
775 }
776 }
777 }
779 /*
780 Local Variables:
781 mode:c++
782 c-file-style:"stroustrup"
783 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
784 indent-tabs-mode:nil
785 fill-column:99
786 End:
787 */
788 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :