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-path.h"
16 #include "libnr/nr-rect-ops.h"
17 #include "libnr/nr-point-fns.h"
18 #include <2geom/path-intersection.h>
19 #include <2geom/point.h>
20 #include <2geom/rect.h>
21 #include "document.h"
22 #include "sp-namedview.h"
23 #include "sp-image.h"
24 #include "sp-item-group.h"
25 #include "sp-item.h"
26 #include "sp-use.h"
27 #include "display/curve.h"
28 #include "inkscape.h"
29 #include "prefs-utils.h"
30 #include "sp-text.h"
31 #include "sp-flowtext.h"
32 #include "text-editing.h"
33 #include "sp-clippath.h"
34 #include "sp-mask.h"
35 #include "helper/geom-curves.h"
36 #include "desktop.h"
38 Inkscape::SnapCandidate::SnapCandidate(SPItem* item, bool clip_or_mask, Geom::Matrix additional_affine)
39 : item(item), clip_or_mask(clip_or_mask), additional_affine(additional_affine)
40 {
41 }
43 Inkscape::SnapCandidate::~SnapCandidate()
44 {
45 }
47 Inkscape::ObjectSnapper::ObjectSnapper(SPNamedView const *nv, Geom::Coord const d)
48 : Snapper(nv, d), _snap_to_itemnode(true), _snap_to_itempath(true),
49 _snap_to_bboxnode(true), _snap_to_bboxpath(true), _snap_to_page_border(false),
50 _strict_snapping(true), _include_item_center(false)
51 {
52 _candidates = new std::vector<SnapCandidate>;
53 _points_to_snap_to = new std::vector<Geom::Point>;
54 _paths_to_snap_to = new std::vector<Geom::PathVector*>;
55 }
57 Inkscape::ObjectSnapper::~ObjectSnapper()
58 {
59 _candidates->clear();
60 delete _candidates;
62 _points_to_snap_to->clear();
63 delete _points_to_snap_to;
65 _clear_paths();
66 delete _paths_to_snap_to;
67 }
69 /**
70 * Find all items within snapping range.
71 * \param parent Pointer to the document's root, or to a clipped path or mask object
72 * \param it List of items to ignore
73 * \param first_point If true then this point is the first one from a whole bunch of points
74 * \param bbox_to_snap Bounding box hulling the whole bunch of points, all from the same selection and having the same transformation
75 * \param DimensionToSnap Snap in X, Y, or both directions.
76 */
78 void Inkscape::ObjectSnapper::_findCandidates(SPObject* parent,
79 std::vector<SPItem const *> const *it,
80 bool const &first_point,
81 Geom::Rect const &bbox_to_snap,
82 DimensionToSnap const snap_dim,
83 bool const clip_or_mask,
84 Geom::Matrix const additional_affine) const // transformation of the item being clipped / masked
85 {
86 bool const c1 = (snap_dim == TRANSL_SNAP_XY) && ThisSnapperMightSnap();
87 bool const c2 = (snap_dim != TRANSL_SNAP_XY) && GuidesMightSnap();
89 if (!(c1 || c2)) {
90 return;
91 }
93 if (first_point) {
94 _candidates->clear();
95 }
97 Geom::Rect bbox_to_snap_incl = bbox_to_snap; // _incl means: will include the snapper tolerance
98 bbox_to_snap_incl.expandBy(getSnapperTolerance()); // see?
100 for (SPObject* o = sp_object_first_child(parent); o != NULL; o = SP_OBJECT_NEXT(o)) {
101 g_assert(_named_view->snap_manager.getDesktop() != NULL);
102 if (SP_IS_ITEM(o) && !SP_ITEM(o)->isLocked() && !(_named_view->snap_manager.getDesktop()->itemIsHidden(SP_ITEM(o)) && !clip_or_mask)) {
103 // Don't snap to locked items, and
104 // don't snap to hidden objects, unless they're a clipped path or a mask
105 /* See if this item is on the ignore list */
106 std::vector<SPItem const *>::const_iterator i;
107 if (it != NULL) {
108 i = it->begin();
109 while (i != it->end() && *i != o) {
110 i++;
111 }
112 }
114 if (it == NULL || i == it->end()) {
115 SPItem *item = SP_ITEM(o);
116 Geom::Matrix transform = Geom::identity();
117 if (item) {
118 SPObject *obj = NULL;
119 if (clip_or_mask) { // If the current item is a clipping path or a mask
120 // then store the transformation of the clipped path or mask itself
121 // but also take into account the additional affine of the object
122 // being clipped / masked
123 transform = to_2geom(item->transform) * additional_affine;
124 } else { // cannot clip or mask more than once
125 // The current item is not a clipping path or a mask, but might
126 // still be the subject of clipping or masking itself ; if so, then
127 // we should also consider that path or mask for snapping to
128 obj = SP_OBJECT(item->clip_ref->getObject());
129 if (obj) {
130 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, item->transform);
131 }
132 obj = SP_OBJECT(item->mask_ref->getObject());
133 if (obj) {
134 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, item->transform);
135 }
136 }
137 }
139 if (SP_IS_GROUP(o)) {
140 _findCandidates(o, it, false, bbox_to_snap, snap_dim, false, Geom::identity());
141 } else {
142 boost::optional<NR::Rect> bbox_of_item = NR::Rect();
143 if (clip_or_mask) {
144 // Oh oh, this will get ugly. We cannot use sp_item_i2d_affine directly because we need to
145 // insert an additional transformation in document coordinates (code copied from sp_item_i2d_affine)
146 sp_item_invoke_bbox(item,
147 bbox_of_item,
148 from_2geom(to_2geom(sp_item_i2doc_affine(item)) * matrix_to_desktop(additional_affine, item)),
149 true);
150 } else {
151 sp_item_invoke_bbox(item, bbox_of_item, sp_item_i2d_affine(item), true);
152 }
153 if (bbox_of_item) {
154 // See if the item is within range
155 if (bbox_to_snap_incl.intersects(to_2geom(*bbox_of_item))) {
156 // This item is within snapping range, so record it as a candidate
157 _candidates->push_back(SnapCandidate(item, clip_or_mask, additional_affine));
158 }
159 }
160 }
161 }
162 }
163 }
164 }
167 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::Snapper::PointType const &t,
168 bool const &first_point) const
169 {
170 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
171 // e.g. when translating an item using the selector tool, then we will only do this for the
172 // first point and store the collection for later use. This significantly improves the performance
173 if (first_point) {
174 _points_to_snap_to->clear();
176 // Determine the type of bounding box we should snap to
177 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
179 bool p_is_a_node = t & Inkscape::Snapper::SNAPPOINT_NODE;
180 bool p_is_a_bbox = t & Inkscape::Snapper::SNAPPOINT_BBOX;
181 bool p_is_a_guide = t & Inkscape::Snapper::SNAPPOINT_GUIDE;
183 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
184 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));
186 if (_snap_to_bboxnode) {
187 int prefs_bbox = prefs_get_int_attribute("tools", "bounding_box", 0);
188 bbox_type = (prefs_bbox == 0)?
189 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
190 }
192 // Consider the page border for snapping
193 if (_snap_to_page_border) {
194 _getBorderNodes(_points_to_snap_to);
195 }
197 for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
198 //Geom::Matrix i2doc(Geom::identity());
199 SPItem *root_item = (*i).item;
200 if (SP_IS_USE((*i).item)) {
201 root_item = sp_use_root(SP_USE((*i).item));
202 }
203 g_return_if_fail(root_item);
205 //Collect all nodes so we can snap to them
206 if (_snap_to_itemnode) {
207 if (!(_strict_snapping && !p_is_a_node) || p_is_a_guide) {
208 std::vector<NR::Point> dummy_vctr;
209 sp_item_snappoints(root_item, _include_item_center, SnapPointsIter(dummy_vctr));
210 to_2geom(dummy_vctr, *_points_to_snap_to);
211 }
212 }
214 //Collect the bounding box's corners so we can snap to them
215 if (_snap_to_bboxnode) {
216 if (!(_strict_snapping && !p_is_a_bbox) || p_is_a_guide) {
217 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
218 // of the item AND the bbox of the clipping path at the same time
219 if (!(*i).clip_or_mask) {
220 boost::optional<NR::Rect> b = sp_item_bbox_desktop(root_item, bbox_type);
221 if (b) {
222 for ( unsigned k = 0 ; k < 4 ; k++ ) {
223 _points_to_snap_to->push_back(to_2geom(b->corner(k)));
224 }
225 }
226 }
227 }
228 }
229 }
230 }
231 }
233 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
234 Inkscape::Snapper::PointType const &t,
235 Geom::Point const &p,
236 bool const &first_point,
237 std::vector<Geom::Point> *unselected_nodes) const
238 {
239 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
241 _collectNodes(t, first_point);
243 if (unselected_nodes != NULL) {
244 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
245 }
247 SnappedPoint s;
248 bool success = false;
250 for (std::vector<Geom::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
251 Geom::Coord dist = Geom::L2(*k - p);
252 if (dist < getSnapperTolerance() && dist < s.getDistance()) {
253 s = SnappedPoint(*k, SNAPTARGET_NODE, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
254 success = true;
255 }
256 }
258 if (success) {
259 sc.points.push_back(s);
260 }
261 }
263 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
264 Inkscape::Snapper::PointType const &t,
265 Geom::Point const &p,
266 Geom::Point const &guide_normal) const
267 {
268 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
269 _collectNodes(t, true);
271 SnappedPoint s;
272 bool success = false;
274 Geom::Coord tol = getSnapperTolerance();
276 for (std::vector<Geom::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
277 // Project each node (*k) on the guide line (running through point p)
278 Geom::Point p_proj = project_on_linesegment(*k, p, p + Geom::rot90(guide_normal));
279 Geom::Coord dist = Geom::L2(*k - p_proj); // distance from node to the guide
280 Geom::Coord dist2 = Geom::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
281 if ((dist < tol && dist2 < tol || getSnapperAlwaysSnap()) && dist < s.getDistance()) {
282 s = SnappedPoint(*k, SNAPTARGET_NODE, dist, tol, getSnapperAlwaysSnap());
283 success = true;
284 }
285 }
287 if (success) {
288 sc.points.push_back(s);
289 }
290 }
293 /**
294 * Returns index of first NR_END bpath in array.
295 */
297 /* Obsolete
298 static unsigned sp_bpath_length(NArtBpath const bpath[])
299 {
300 g_return_val_if_fail(bpath != NULL, FALSE);
301 unsigned ret = 0;
302 while ( bpath[ret].code != NR_END ) {
303 ++ret;
304 }
305 ++ret;
306 return ret;
307 }*/
309 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::Snapper::PointType const &t,
310 bool const &first_point) const
311 {
312 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
313 // e.g. when translating an item using the selector tool, then we will only do this for the
314 // first point and store the collection for later use. This significantly improves the performance
315 if (first_point) {
316 _clear_paths();
318 // Determine the type of bounding box we should snap to
319 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
321 bool p_is_a_node = t & Inkscape::Snapper::SNAPPOINT_NODE;
323 if (_snap_to_bboxpath) {
324 int prefs_bbox = prefs_get_int_attribute("tools", "bounding_box", 0);
325 bbox_type = (prefs_bbox ==0)?
326 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
327 }
329 // Consider the page border for snapping
330 if (_snap_to_page_border) {
331 Geom::PathVector *border_path = _getBorderPathv();
332 if (border_path != NULL) {
333 _paths_to_snap_to->push_back(border_path);
334 }
335 }
337 for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
339 /* Transform the requested snap point to this item's coordinates */
340 Geom::Matrix i2doc(Geom::identity());
341 SPItem *root_item = NULL;
342 /* We might have a clone at hand, so make sure we get the root item */
343 if (SP_IS_USE((*i).item)) {
344 i2doc = sp_use_get_root_transform(SP_USE((*i).item));
345 root_item = sp_use_root(SP_USE((*i).item));
346 g_return_if_fail(root_item);
347 } else {
348 i2doc = sp_item_i2doc_affine((*i).item);
349 root_item = (*i).item;
350 }
352 //Build a list of all paths considered for snapping to
354 //Add the item's path to snap to
355 if (_snap_to_itempath) {
356 if (!(_strict_snapping && !p_is_a_node)) {
357 // Snapping to the path of characters is very cool, but for a large
358 // chunk of text this will take ages! So limit snapping to text paths
359 // containing max. 240 characters. Snapping the bbox will not be affected
360 bool very_lenghty_prose = false;
361 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
362 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
363 }
364 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
365 // which corresponds to a lag of 500 msec. This is for snapping a rect
366 // to a single line of text.
368 // Snapping for example to a traced bitmap is also very stressing for
369 // the CPU, so we'll only snap to paths having no more than 500 nodes
370 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
371 bool very_complex_path = false;
372 if (SP_IS_PATH(root_item)) {
373 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
374 }
376 if (!very_lenghty_prose && !very_complex_path) {
377 SPCurve *curve = curve_for_item(root_item);
378 if (curve) {
379 // We will get our own copy of the path, which must be freed at some point
380 Geom::PathVector *borderpathv = pathvector_for_curve(root_item, curve, true, true, Geom::identity(), (*i).additional_affine);
381 _paths_to_snap_to->push_back(borderpathv); // Perhaps for speed, get a reference to the Geom::pathvector, and store the transformation besides it.
382 curve->unref();
383 }
384 }
385 }
386 }
388 //Add the item's bounding box to snap to
389 if (_snap_to_bboxpath) {
390 if (!(_strict_snapping && p_is_a_node)) {
391 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
392 // of the item AND the bbox of the clipping path at the same time
393 if (!(*i).clip_or_mask) {
394 NRRect rect;
395 sp_item_invoke_bbox(root_item, &rect, i2doc, TRUE, bbox_type);
396 Geom::Rect const rect2 = to_2geom(*rect.upgrade());
397 Geom::PathVector *path = _getPathvFromRect(rect2);
398 _paths_to_snap_to->push_back(path);
399 }
400 }
401 }
402 }
403 }
404 }
406 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
407 Inkscape::Snapper::PointType const &t,
408 Geom::Point const &p,
409 bool const &first_point,
410 std::vector<Geom::Point> *unselected_nodes,
411 SPPath const *selected_path) const
412 {
413 _collectPaths(t, first_point);
414 // Now we can finally do the real snapping, using the paths collected above
416 g_assert(_named_view->snap_manager.getDesktop() != NULL);
417 Geom::Point const p_doc = _named_view->snap_manager.getDesktop()->dt2doc(p);
419 bool const node_tool_active = _snap_to_itempath && selected_path != NULL;
421 if (first_point) {
422 /* While editing a path in the node tool, findCandidates must ignore that path because
423 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
424 * This path must not be ignored however when snapping to the paths, so we add it here
425 * manually when applicable.
426 *
427 * Note that this path must be the last in line!
428 * */
429 if (node_tool_active) {
430 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
431 if (curve) {
432 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
433 _paths_to_snap_to->push_back(pathv);
434 curve->unref();
435 }
436 }
437 }
439 for (std::vector<Geom::PathVector*>::const_iterator it_p = _paths_to_snap_to->begin(); it_p != _paths_to_snap_to->end(); it_p++) {
440 bool const being_edited = (node_tool_active && (*it_p) == _paths_to_snap_to->back());
441 //if true then this pathvector it_pv is currently being edited in the node tool
443 // char * svgd = sp_svg_write_path(**it_p);
444 // std::cout << "Dumping the pathvector: " << svgd << std::endl;
446 for(Geom::PathVector::iterator it_pv = (*it_p)->begin(); it_pv != (*it_p)->end(); ++it_pv) {
447 // Find a nearest point for each curve within this path
448 // n curves will return n time values with 0 <= t <= 1
449 std::vector<double> anp = (*it_pv).nearestPointPerCurve(p_doc);
451 std::vector<double>::const_iterator np = anp.begin();
452 unsigned int index = 0;
453 for (; np != anp.end(); np++, index++) {
454 Geom::Curve const *curve = &((*it_pv).at_index(index));
455 Geom::Point const sp_doc = curve->pointAt(*np);
457 bool c1 = true;
458 bool c2 = true;
459 if (being_edited) {
460 /* If the path is being edited, then we should only snap though to stationary pieces of the path
461 * and not to the pieces that are being dragged around. This way we avoid
462 * self-snapping. For this we check whether the nodes at both ends of the current
463 * piece are unselected; if they are then this piece must be stationary
464 */
465 g_assert(unselected_nodes != NULL);
466 Geom::Point start_pt = _named_view->snap_manager.getDesktop()->doc2dt(curve->pointAt(0));
467 Geom::Point end_pt = _named_view->snap_manager.getDesktop()->doc2dt(curve->pointAt(1));
468 c1 = isUnselectedNode(start_pt, unselected_nodes);
469 c2 = isUnselectedNode(end_pt, unselected_nodes);
470 }
472 Geom::Point const sp_dt = _named_view->snap_manager.getDesktop()->doc2dt(sp_doc);
473 if (!being_edited || (c1 && c2)) {
474 Geom::Coord const dist = Geom::distance(sp_doc, p_doc);
475 if (dist < getSnapperTolerance()) {
476 sc.curves.push_back(Inkscape::SnappedCurve(from_2geom(sp_dt), dist, getSnapperTolerance(), getSnapperAlwaysSnap(), curve));
477 }
478 }
479 }
480 } // End of: for (Geom::PathVector::iterator ....)
481 }
482 }
484 /* Returns true if point is coincident with one of the unselected nodes */
485 bool Inkscape::ObjectSnapper::isUnselectedNode(Geom::Point const &point, std::vector<Geom::Point> const *unselected_nodes) const
486 {
487 if (unselected_nodes == NULL) {
488 return false;
489 }
491 if (unselected_nodes->size() == 0) {
492 return false;
493 }
495 for (std::vector<Geom::Point>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
496 if (Geom::L2(point - *i) < 1e-4) {
497 return true;
498 }
499 }
501 return false;
502 }
504 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
505 Inkscape::Snapper::PointType const &t,
506 Geom::Point const &p,
507 bool const &first_point,
508 ConstraintLine const &c) const
509 {
511 _collectPaths(t, first_point);
513 // Now we can finally do the real snapping, using the paths collected above
515 g_assert(_named_view->snap_manager.getDesktop() != NULL);
516 Geom::Point const p_doc = _named_view->snap_manager.getDesktop()->dt2doc(p);
518 Geom::Point direction_vector = c.getDirection();
519 if (!is_zero(direction_vector)) {
520 direction_vector = Geom::unit_vector(direction_vector);
521 }
523 Geom::Point const p1_on_cl = c.hasPoint() ? c.getPoint() : p;
524 Geom::Point const p2_on_cl = p1_on_cl + direction_vector;
526 // The intersection point of the constraint line with any path,
527 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
528 // The distance between those points is twice the snapping tolerance
529 Geom::Point const p_proj_on_cl = project_on_linesegment(p, p1_on_cl, p2_on_cl);
530 Geom::Point const p_min_on_cl = _named_view->snap_manager.getDesktop()->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
531 Geom::Point const p_max_on_cl = _named_view->snap_manager.getDesktop()->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
533 Geom::Path cl;
534 std::vector<Geom::Path> clv;
535 cl.start(p_min_on_cl);
536 cl.appendNew<Geom::LineSegment>(p_max_on_cl);
537 clv.push_back(cl);
539 for (std::vector<Geom::PathVector*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
540 if (*k) {
541 Geom::CrossingSet cs = Geom::crossings(clv, *(*k));
542 if (cs.size() > 0) {
543 // We need only the first element of cs, because cl is only a single straight linesegment
544 // This first element contains a vector filled with crossings of cl with *k
545 for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
546 if ((*m).ta >= 0 && (*m).ta <= 1 ) {
547 // Reconstruct the point of intersection
548 Geom::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
549 // When it's within snapping range, then return it
550 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
551 Geom::Coord dist = Geom::L2(_named_view->snap_manager.getDesktop()->dt2doc(p_proj_on_cl) - p_inters);
552 SnappedPoint s(_named_view->snap_manager.getDesktop()->doc2dt(p_inters), SNAPTARGET_PATH, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
553 sc.points.push_back(s);
554 }
555 }
556 }
557 }
558 }
559 }
562 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
563 Inkscape::Snapper::PointType const &t,
564 Geom::Point const &p,
565 bool const &first_point,
566 boost::optional<Geom::Rect> const &bbox_to_snap,
567 std::vector<SPItem const *> const *it,
568 std::vector<Geom::Point> *unselected_nodes) const
569 {
570 if (_snap_enabled == false || getSnapFrom(t) == false || _named_view == NULL) {
571 return;
572 }
574 /* Get a list of all the SPItems that we will try to snap to */
575 if (first_point) {
576 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
577 _findCandidates(sp_document_root(_named_view->document), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
578 }
580 if (_snap_to_itemnode || _snap_to_bboxnode || _snap_to_page_border) {
581 _snapNodes(sc, t, p, first_point, unselected_nodes);
582 }
584 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
585 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
586 if (n > 0) {
587 /* While editing a path in the node tool, findCandidates must ignore that path because
588 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
589 * That path must not be ignored however when snapping to the paths, so we add it here
590 * manually when applicable
591 */
592 SPPath *path = NULL;
593 if (it != NULL) {
594 g_assert(SP_IS_PATH(*it->begin()));
595 g_assert(it->size() == 1);
596 path = SP_PATH(*it->begin());
597 }
598 _snapPaths(sc, t, p, first_point, unselected_nodes, path);
599 } else {
600 _snapPaths(sc, t, p, first_point, NULL, NULL);
601 }
602 }
603 }
605 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
606 Inkscape::Snapper::PointType const &t,
607 Geom::Point const &p,
608 bool const &first_point,
609 boost::optional<Geom::Rect> const &bbox_to_snap,
610 ConstraintLine const &c,
611 std::vector<SPItem const *> const *it) const
612 {
613 if (_snap_enabled == false || getSnapFrom(t) == false || _named_view == NULL) {
614 return;
615 }
617 /* Get a list of all the SPItems that we will try to snap to */
618 if (first_point) {
619 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
620 _findCandidates(sp_document_root(_named_view->document), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
621 }
623 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
624 // This is usefull for example when scaling an object while maintaining a fixed aspect ratio. It's
625 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
627 // When snapping to objects, we either snap to their nodes or their paths. It is however very
628 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
629 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
630 // so we will more or less snap to them anyhow.
632 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
633 _snapPathsConstrained(sc, t, p, first_point, c);
634 }
635 }
638 // This method is used to snap a guide to nodes, while dragging the guide around
639 void Inkscape::ObjectSnapper::guideSnap(SnappedConstraints &sc,
640 Geom::Point const &p,
641 Geom::Point const &guide_normal) const
642 {
643 if ( NULL == _named_view ) {
644 return;
645 }
647 /* Get a list of all the SPItems that we will try to snap to */
648 std::vector<SPItem*> cand;
649 std::vector<SPItem const *> const it; //just an empty list
651 DimensionToSnap snap_dim;
652 if (guide_normal == to_2geom(component_vectors[Geom::Y])) {
653 snap_dim = GUIDE_TRANSL_SNAP_Y;
654 } else if (guide_normal == to_2geom(component_vectors[Geom::X])) {
655 snap_dim = GUIDE_TRANSL_SNAP_X;
656 } else {
657 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
658 }
660 // We don't support ANGLED_GUIDE_ROT_SNAP yet.
662 // It would be cool to allow the user to rotate a guide by dragging it, instead of
663 // only translating it. (For example when CTRL is pressed). We will need an UI part
664 // for that first; and some important usability choices need to be made:
665 // E.g. which point should be used for pivoting? A previously snapped point,
666 // or a transformation center (which can be moved after clicking for the
667 // second time on an object; but should this point then be constrained to the
668 // line, or can it be located anywhere?)
670 _findCandidates(sp_document_root(_named_view->document), &it, true, Geom::Rect(p, p), snap_dim, false, Geom::identity());
671 _snapTranslatingGuideToNodes(sc, Inkscape::Snapper::SNAPPOINT_GUIDE, p, guide_normal);
672 // _snapRotatingGuideToNodes has not been implemented yet.
673 }
675 /**
676 * \return true if this Snapper will snap at least one kind of point.
677 */
678 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
679 {
680 bool snap_to_something = _snap_to_itempath || _snap_to_itemnode || _snap_to_bboxpath || _snap_to_bboxnode || _snap_to_page_border;
681 return (_snap_enabled && _snap_from != 0 && snap_to_something);
682 }
684 bool Inkscape::ObjectSnapper::GuidesMightSnap() const
685 {
686 bool snap_to_something = _snap_to_itemnode || _snap_to_bboxnode;
687 return (_snap_enabled && (_snap_from & SNAPPOINT_GUIDE) && snap_to_something);
688 }
690 void Inkscape::ObjectSnapper::_clear_paths() const
691 {
692 for (std::vector<Geom::PathVector*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
693 g_free(*k);
694 }
695 _paths_to_snap_to->clear();
696 }
698 Geom::PathVector* Inkscape::ObjectSnapper::_getBorderPathv() const
699 {
700 Geom::Rect const border_rect = Geom::Rect(Geom::Point(0,0), Geom::Point(sp_document_width(_named_view->document),sp_document_height(_named_view->document)));
701 return _getPathvFromRect(border_rect);
702 }
704 Geom::PathVector* Inkscape::ObjectSnapper::_getPathvFromRect(Geom::Rect const rect) const
705 {
706 SPCurve const *border_curve = SPCurve::new_from_rect(rect);
707 if (border_curve) {
708 Geom::PathVector *dummy = new Geom::PathVector(border_curve->get_pathvector());
709 return dummy;
710 } else {
711 return NULL;
712 }
713 }
715 void Inkscape::ObjectSnapper::_getBorderNodes(std::vector<Geom::Point> *points) const
716 {
717 Geom::Coord w = sp_document_width(_named_view->document);
718 Geom::Coord h = sp_document_height(_named_view->document);
719 points->push_back(Geom::Point(0,0));
720 points->push_back(Geom::Point(0,h));
721 points->push_back(Geom::Point(w,h));
722 points->push_back(Geom::Point(w,0));
723 }
725 /*
726 Local Variables:
727 mode:c++
728 c-file-style:"stroustrup"
729 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
730 indent-tabs-mode:nil
731 fill-column:99
732 End:
733 */
734 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :