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), _snap_to_itemnode(true), _snap_to_itempath(true),
48 _snap_to_bboxnode(true), _snap_to_bboxpath(true), _snap_to_page_border(false),
49 _strict_snapping(true)
50 {
51 _candidates = new std::vector<SnapCandidate>;
52 _points_to_snap_to = new std::vector<Geom::Point>;
53 _paths_to_snap_to = new std::vector<Geom::PathVector*>;
54 }
56 Inkscape::ObjectSnapper::~ObjectSnapper()
57 {
58 _candidates->clear();
59 delete _candidates;
61 _points_to_snap_to->clear();
62 delete _points_to_snap_to;
64 _clear_paths();
65 delete _paths_to_snap_to;
66 }
68 /**
69 * Find all items within snapping range.
70 * \param parent Pointer to the document's root, or to a clipped path or mask object
71 * \param it List of items to ignore
72 * \param first_point If true then this point is the first one from a whole bunch of points
73 * \param bbox_to_snap Bounding box hulling the whole bunch of points, all from the same selection and having the same transformation
74 * \param DimensionToSnap Snap in X, Y, or both directions.
75 */
77 void Inkscape::ObjectSnapper::_findCandidates(SPObject* parent,
78 std::vector<SPItem const *> const *it,
79 bool const &first_point,
80 Geom::Rect const &bbox_to_snap,
81 DimensionToSnap const snap_dim,
82 bool const clip_or_mask,
83 Geom::Matrix const additional_affine) const // transformation of the item being clipped / masked
84 {
85 bool const c1 = (snap_dim == TRANSL_SNAP_XY) && ThisSnapperMightSnap();
86 bool const c2 = (snap_dim != TRANSL_SNAP_XY) && GuidesMightSnap();
88 if (!(c1 || c2)) {
89 return;
90 }
92 if (first_point) {
93 _candidates->clear();
94 }
96 Geom::Rect bbox_to_snap_incl = bbox_to_snap; // _incl means: will include the snapper tolerance
97 bbox_to_snap_incl.expandBy(getSnapperTolerance()); // see?
99 for (SPObject* o = sp_object_first_child(parent); o != NULL; o = SP_OBJECT_NEXT(o)) {
100 g_assert(_snapmanager->getDesktop() != NULL);
101 if (SP_IS_ITEM(o) && !SP_ITEM(o)->isLocked() && !(_snapmanager->getDesktop()->itemIsHidden(SP_ITEM(o)) && !clip_or_mask)) {
102 // Don't snap to locked items, and
103 // don't snap to hidden objects, unless they're a clipped path or a mask
104 /* See if this item is on the ignore list */
105 std::vector<SPItem const *>::const_iterator i;
106 if (it != NULL) {
107 i = it->begin();
108 while (i != it->end() && *i != o) {
109 i++;
110 }
111 }
113 if (it == NULL || i == it->end()) {
114 SPItem *item = SP_ITEM(o);
115 if (item) {
116 SPObject *obj = NULL;
117 if (!clip_or_mask) { // cannot clip or mask more than once
118 // The current item is not a clipping path or a mask, but might
119 // still be the subject of clipping or masking itself ; if so, then
120 // we should also consider that path or mask for snapping to
121 obj = SP_OBJECT(item->clip_ref->getObject());
122 if (obj) {
123 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
124 }
125 obj = SP_OBJECT(item->mask_ref->getObject());
126 if (obj) {
127 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
128 }
129 }
130 }
132 if (SP_IS_GROUP(o)) {
133 _findCandidates(o, it, false, bbox_to_snap, snap_dim, clip_or_mask, additional_affine);
134 } else {
135 Geom::OptRect bbox_of_item = Geom::Rect();
136 if (clip_or_mask) {
137 // Oh oh, this will get ugly. We cannot use sp_item_i2d_affine directly because we need to
138 // insert an additional transformation in document coordinates (code copied from sp_item_i2d_affine)
139 sp_item_invoke_bbox(item,
140 bbox_of_item,
141 sp_item_i2doc_affine(item) * additional_affine * _snapmanager->getDesktop()->doc2dt(),
142 true);
143 } else {
144 sp_item_invoke_bbox(item, bbox_of_item, sp_item_i2d_affine(item), true);
145 }
146 if (bbox_of_item) {
147 // See if the item is within range
148 if (bbox_to_snap_incl.intersects(*bbox_of_item)) {
149 // This item is within snapping range, so record it as a candidate
150 _candidates->push_back(SnapCandidate(item, clip_or_mask, additional_affine));
151 }
152 }
153 }
154 }
155 }
156 }
157 }
160 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::SnapPreferences::PointType const &t,
161 bool const &first_point) const
162 {
163 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
164 // e.g. when translating an item using the selector tool, then we will only do this for the
165 // first point and store the collection for later use. This significantly improves the performance
166 if (first_point) {
167 _points_to_snap_to->clear();
169 // Determine the type of bounding box we should snap to
170 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
172 bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
173 bool p_is_a_bbox = t & Inkscape::SnapPreferences::SNAPPOINT_BBOX;
174 bool p_is_a_guide = t & Inkscape::SnapPreferences::SNAPPOINT_GUIDE;
176 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
177 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)));
179 if (_snap_to_bboxnode) {
180 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
181 bool prefs_bbox = prefs->getBool("/tools/bounding_box");
182 bbox_type = !prefs_bbox ?
183 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
184 }
186 // Consider the page border for snapping
187 if (_snap_to_page_border) {
188 _getBorderNodes(_points_to_snap_to);
189 }
191 for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
192 //Geom::Matrix i2doc(Geom::identity());
193 SPItem *root_item = (*i).item;
194 if (SP_IS_USE((*i).item)) {
195 root_item = sp_use_root(SP_USE((*i).item));
196 }
197 g_return_if_fail(root_item);
199 //Collect all nodes so we can snap to them
200 if (_snap_to_itemnode) {
201 if (!(_strict_snapping && !p_is_a_node) || p_is_a_guide) {
202 // Note: there are two ways in which intersections are considered:
203 // Method 1: Intersections are calculated for each shape individually, for both the
204 // snap source and snap target (see sp_shape_snappoints)
205 // Method 2: Intersections are calculated for each curve or line that we've snapped to, i.e. only for
206 // the target (see the intersect() method in the SnappedCurve and SnappedLine classes)
207 // Some differences:
208 // - Method 1 doesn't find intersections within a set of multiple objects
209 // - Method 2 only works for targets
210 // When considering intersections as snap targets:
211 // - Method 1 only works when snapping to nodes, whereas
212 // - Method 2 only works when snapping to paths
213 // - There will be performance differences too!
214 // If both methods are being used simultaneously, then this might lead to duplicate targets!
216 // Well, here we will be looking for snap TARGETS. Both methods can therefore be used.
217 // When snapping to paths, we will get a collection of snapped lines and snapped curves. findBestSnap() will
218 // go hunting for intersections (but only when asked to in the prefs of course). In that case we can just
219 // temporarily block the intersections in sp_item_snappoints, we don't need duplicates. If we're not snapping to
220 // paths though but only to item nodes then we should still look for the intersections in sp_item_snappoints()
221 bool old_pref = _snapmanager->snapprefs.getSnapIntersectionCS();
222 if (_snap_to_itempath) {
223 _snapmanager->snapprefs.setSnapIntersectionCS(false);
224 }
226 sp_item_snappoints(root_item, SnapPointsIter(*_points_to_snap_to), &_snapmanager->snapprefs);
228 if (_snap_to_itempath) {
229 _snapmanager->snapprefs.setSnapIntersectionCS(old_pref);
230 }
231 }
232 }
234 //Collect the bounding box's corners so we can snap to them
235 if (_snap_to_bboxnode) {
236 if (!(_strict_snapping && !p_is_a_bbox) || p_is_a_guide) {
237 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
238 // of the item AND the bbox of the clipping path at the same time
239 if (!(*i).clip_or_mask) {
240 Geom::OptRect b = sp_item_bbox_desktop(root_item, bbox_type);
241 getBBoxPoints(b, _points_to_snap_to, _snapmanager->snapprefs.getSnapMidpoints());
242 }
243 }
244 }
245 }
246 }
247 }
249 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
250 Inkscape::SnapPreferences::PointType const &t,
251 Geom::Point const &p,
252 bool const &first_point,
253 std::vector<Geom::Point> *unselected_nodes) const
254 {
255 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
257 _collectNodes(t, first_point);
259 if (unselected_nodes != NULL) {
260 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
261 }
263 SnappedPoint s;
264 bool success = false;
266 for (std::vector<Geom::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
267 Geom::Coord dist = Geom::L2(*k - p);
268 if (dist < getSnapperTolerance() && dist < s.getSnapDistance()) {
269 s = SnappedPoint(*k, SNAPTARGET_NODE, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
270 success = true;
271 }
272 }
274 if (success) {
275 sc.points.push_back(s);
276 }
277 }
279 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
280 Inkscape::SnapPreferences::PointType const &t,
281 Geom::Point const &p,
282 Geom::Point const &guide_normal) const
283 {
284 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
285 _collectNodes(t, true);
287 SnappedPoint s;
288 bool success = false;
290 Geom::Coord tol = getSnapperTolerance();
292 for (std::vector<Geom::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
293 // Project each node (*k) on the guide line (running through point p)
294 Geom::Point p_proj = project_on_linesegment(*k, p, p + Geom::rot90(guide_normal));
295 Geom::Coord dist = Geom::L2(*k - p_proj); // distance from node to the guide
296 Geom::Coord dist2 = Geom::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
297 if ((dist < tol && dist2 < tol) || (getSnapperAlwaysSnap() && dist < s.getSnapDistance())) {
298 s = SnappedPoint(*k, SNAPTARGET_NODE, dist, tol, getSnapperAlwaysSnap(), true);
299 success = true;
300 }
301 }
303 if (success) {
304 sc.points.push_back(s);
305 }
306 }
309 /**
310 * Returns index of first NR_END bpath in array.
311 */
313 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::SnapPreferences::PointType const &t,
314 bool const &first_point) const
315 {
316 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
317 // e.g. when translating an item using the selector tool, then we will only do this for the
318 // first point and store the collection for later use. This significantly improves the performance
319 if (first_point) {
320 _clear_paths();
322 // Determine the type of bounding box we should snap to
323 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
325 bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
327 if (_snap_to_bboxpath) {
328 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
329 int prefs_bbox = prefs->getBool("/tools/bounding_box", 0);
330 bbox_type = !prefs_bbox ?
331 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
332 }
334 // Consider the page border for snapping
335 if (_snap_to_page_border) {
336 Geom::PathVector *border_path = _getBorderPathv();
337 if (border_path != NULL) {
338 _paths_to_snap_to->push_back(border_path);
339 }
340 }
342 for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
344 /* Transform the requested snap point to this item's coordinates */
345 Geom::Matrix i2doc(Geom::identity());
346 SPItem *root_item = NULL;
347 /* We might have a clone at hand, so make sure we get the root item */
348 if (SP_IS_USE((*i).item)) {
349 i2doc = sp_use_get_root_transform(SP_USE((*i).item));
350 root_item = sp_use_root(SP_USE((*i).item));
351 g_return_if_fail(root_item);
352 } else {
353 i2doc = sp_item_i2doc_affine((*i).item);
354 root_item = (*i).item;
355 }
357 //Build a list of all paths considered for snapping to
359 //Add the item's path to snap to
360 if (_snap_to_itempath) {
361 if (!(_strict_snapping && !p_is_a_node)) {
362 // Snapping to the path of characters is very cool, but for a large
363 // chunk of text this will take ages! So limit snapping to text paths
364 // containing max. 240 characters. Snapping the bbox will not be affected
365 bool very_lenghty_prose = false;
366 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
367 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
368 }
369 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
370 // which corresponds to a lag of 500 msec. This is for snapping a rect
371 // to a single line of text.
373 // Snapping for example to a traced bitmap is also very stressing for
374 // the CPU, so we'll only snap to paths having no more than 500 nodes
375 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
376 bool very_complex_path = false;
377 if (SP_IS_PATH(root_item)) {
378 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
379 }
381 if (!very_lenghty_prose && !very_complex_path) {
382 SPCurve *curve = curve_for_item(root_item);
383 if (curve) {
384 // We will get our own copy of the path, which must be freed at some point
385 Geom::PathVector *borderpathv = pathvector_for_curve(root_item, curve, true, true, Geom::identity(), (*i).additional_affine);
386 _paths_to_snap_to->push_back(borderpathv); // Perhaps for speed, get a reference to the Geom::pathvector, and store the transformation besides it.
387 curve->unref();
388 }
389 }
390 }
391 }
393 //Add the item's bounding box to snap to
394 if (_snap_to_bboxpath) {
395 if (!(_strict_snapping && p_is_a_node)) {
396 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
397 // of the item AND the bbox of the clipping path at the same time
398 if (!(*i).clip_or_mask) {
399 Geom::OptRect rect;
400 sp_item_invoke_bbox(root_item, rect, i2doc, TRUE, bbox_type);
401 if (rect) {
402 Geom::PathVector *path = _getPathvFromRect(*rect);
403 _paths_to_snap_to->push_back(path);
404 }
405 }
406 }
407 }
408 }
409 }
410 }
412 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
413 Inkscape::SnapPreferences::PointType const &t,
414 Geom::Point const &p,
415 bool const &first_point,
416 std::vector<Geom::Point> *unselected_nodes,
417 SPPath const *selected_path) const
418 {
419 _collectPaths(t, first_point);
420 // Now we can finally do the real snapping, using the paths collected above
422 g_assert(_snapmanager->getDesktop() != NULL);
423 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p);
425 bool const node_tool_active = _snap_to_itempath && selected_path != NULL;
427 if (first_point) {
428 /* findCandidates() is used for snapping to both paths and nodes. It ignores the path that is
429 * currently being edited, because that path requires special care: when snapping to nodes
430 * only the unselected nodes of that path should be considered, and these will be passed on separately.
431 * This path must not be ignored however when snapping to the paths, so we add it here
432 * manually when applicable.
433 *
434 * Note that this path must be the last in line!
435 * */
436 if (node_tool_active) {
437 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
438 if (curve) {
439 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
440 _paths_to_snap_to->push_back(pathv);
441 curve->unref();
442 }
443 }
444 }
446 for (std::vector<Geom::PathVector*>::const_iterator it_p = _paths_to_snap_to->begin(); it_p != _paths_to_snap_to->end(); it_p++) {
447 bool const being_edited = (node_tool_active && (*it_p) == _paths_to_snap_to->back());
448 //if true then this pathvector it_pv is currently being edited in the node tool
450 // char * svgd = sp_svg_write_path(**it_p);
451 // std::cout << "Dumping the pathvector: " << svgd << std::endl;
453 for(Geom::PathVector::iterator it_pv = (*it_p)->begin(); it_pv != (*it_p)->end(); ++it_pv) {
454 // Find a nearest point for each curve within this path
455 // n curves will return n time values with 0 <= t <= 1
456 std::vector<double> anp = (*it_pv).nearestPointPerCurve(p_doc);
458 std::vector<double>::const_iterator np = anp.begin();
459 unsigned int index = 0;
460 for (; np != anp.end(); np++, index++) {
461 Geom::Curve const *curve = &((*it_pv).at_index(index));
462 Geom::Point const sp_doc = curve->pointAt(*np);
464 bool c1 = true;
465 bool c2 = true;
466 if (being_edited) {
467 /* If the path is being edited, then we should only snap though to stationary pieces of the path
468 * and not to the pieces that are being dragged around. This way we avoid
469 * self-snapping. For this we check whether the nodes at both ends of the current
470 * piece are unselected; if they are then this piece must be stationary
471 */
472 g_assert(unselected_nodes != NULL);
473 Geom::Point start_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(0));
474 Geom::Point end_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(1));
475 c1 = isUnselectedNode(start_pt, unselected_nodes);
476 c2 = isUnselectedNode(end_pt, unselected_nodes);
477 /* Unfortunately, this might yield false positives for coincident nodes. Inkscape might therefore mistakenly
478 * snap to path segments that are not stationary. There are at least two possible ways to overcome this:
479 * - Linking the individual nodes of the SPPath we have here, to the nodes of the NodePath::SubPath class as being
480 * used in sp_nodepath_selected_nodes_move. This class has a member variable called "selected". For this the nodes
481 * should be in the exact same order for both classes, so we can index them
482 * - Replacing the SPPath being used here by the the NodePath::SubPath class; but how?
483 */
484 }
486 Geom::Point const sp_dt = _snapmanager->getDesktop()->doc2dt(sp_doc);
487 if (!being_edited || (c1 && c2)) {
488 Geom::Coord const dist = Geom::distance(sp_doc, p_doc);
489 if (dist < getSnapperTolerance()) {
490 sc.curves.push_back(Inkscape::SnappedCurve(sp_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), false, curve));
491 }
492 }
493 }
494 } // End of: for (Geom::PathVector::iterator ....)
495 }
496 }
498 /* Returns true if point is coincident with one of the unselected nodes */
499 bool Inkscape::ObjectSnapper::isUnselectedNode(Geom::Point const &point, std::vector<Geom::Point> const *unselected_nodes) const
500 {
501 if (unselected_nodes == NULL) {
502 return false;
503 }
505 if (unselected_nodes->size() == 0) {
506 return false;
507 }
509 for (std::vector<Geom::Point>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
510 if (Geom::L2(point - *i) < 1e-4) {
511 return true;
512 }
513 }
515 return false;
516 }
518 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
519 Inkscape::SnapPreferences::PointType const &t,
520 Geom::Point const &p,
521 bool const &first_point,
522 ConstraintLine const &c) const
523 {
525 _collectPaths(t, first_point);
527 // Now we can finally do the real snapping, using the paths collected above
529 g_assert(_snapmanager->getDesktop() != NULL);
530 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p);
532 Geom::Point direction_vector = c.getDirection();
533 if (!is_zero(direction_vector)) {
534 direction_vector = Geom::unit_vector(direction_vector);
535 }
537 Geom::Point const p1_on_cl = c.hasPoint() ? c.getPoint() : p;
538 Geom::Point const p2_on_cl = p1_on_cl + direction_vector;
540 // The intersection point of the constraint line with any path,
541 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
542 // The distance between those points is twice the snapping tolerance
543 Geom::Point const p_proj_on_cl = project_on_linesegment(p, p1_on_cl, p2_on_cl);
544 Geom::Point const p_min_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
545 Geom::Point const p_max_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
547 Geom::Path cl;
548 std::vector<Geom::Path> clv;
549 cl.start(p_min_on_cl);
550 cl.appendNew<Geom::LineSegment>(p_max_on_cl);
551 clv.push_back(cl);
553 for (std::vector<Geom::PathVector*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
554 if (*k) {
555 Geom::CrossingSet cs = Geom::crossings(clv, *(*k));
556 if (cs.size() > 0) {
557 // We need only the first element of cs, because cl is only a single straight linesegment
558 // This first element contains a vector filled with crossings of cl with *k
559 for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
560 if ((*m).ta >= 0 && (*m).ta <= 1 ) {
561 // Reconstruct the point of intersection
562 Geom::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
563 // When it's within snapping range, then return it
564 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
565 Geom::Coord dist = Geom::L2(_snapmanager->getDesktop()->dt2doc(p_proj_on_cl) - p_inters);
566 SnappedPoint s(_snapmanager->getDesktop()->doc2dt(p_inters), SNAPTARGET_PATH, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
567 sc.points.push_back(s);
568 }
569 }
570 }
571 }
572 }
573 }
576 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
577 Inkscape::SnapPreferences::PointType const &t,
578 Geom::Point const &p,
579 bool const &first_point,
580 Geom::OptRect const &bbox_to_snap,
581 std::vector<SPItem const *> const *it,
582 std::vector<Geom::Point> *unselected_nodes) const
583 {
584 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false ) {
585 return;
586 }
588 /* Get a list of all the SPItems that we will try to snap to */
589 if (first_point) {
590 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
591 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
592 }
594 if (_snap_to_itemnode || _snap_to_bboxnode || _snap_to_page_border) {
595 _snapNodes(sc, t, p, first_point, unselected_nodes);
596 }
598 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
599 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
600 if (n > 0) {
601 /* While editing a path in the node tool, findCandidates must ignore that path because
602 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
603 * That path must not be ignored however when snapping to the paths, so we add it here
604 * manually when applicable
605 */
606 SPPath *path = NULL;
607 if (it != NULL) {
608 g_assert(SP_IS_PATH(*it->begin()));
609 g_assert(it->size() == 1);
610 path = SP_PATH(*it->begin());
611 }
612 _snapPaths(sc, t, p, first_point, unselected_nodes, path);
613 } else {
614 _snapPaths(sc, t, p, first_point, NULL, NULL);
615 }
616 }
617 }
619 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
620 Inkscape::SnapPreferences::PointType const &t,
621 Geom::Point const &p,
622 bool const &first_point,
623 Geom::OptRect const &bbox_to_snap,
624 ConstraintLine const &c,
625 std::vector<SPItem const *> const *it) const
626 {
627 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false) {
628 return;
629 }
631 /* Get a list of all the SPItems that we will try to snap to */
632 if (first_point) {
633 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
634 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
635 }
637 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
638 // This is usefull for example when scaling an object while maintaining a fixed aspect ratio. It's
639 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
641 // When snapping to objects, we either snap to their nodes or their paths. It is however very
642 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
643 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
644 // so we will more or less snap to them anyhow.
646 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
647 _snapPathsConstrained(sc, t, p, first_point, c);
648 }
649 }
652 // This method is used to snap a guide to nodes, while dragging the guide around
653 void Inkscape::ObjectSnapper::guideSnap(SnappedConstraints &sc,
654 Geom::Point const &p,
655 Geom::Point const &guide_normal) const
656 {
657 /* Get a list of all the SPItems that we will try to snap to */
658 std::vector<SPItem*> cand;
659 std::vector<SPItem const *> const it; //just an empty list
661 DimensionToSnap snap_dim;
662 if (guide_normal == to_2geom(component_vectors[Geom::Y])) {
663 snap_dim = GUIDE_TRANSL_SNAP_Y;
664 } else if (guide_normal == to_2geom(component_vectors[Geom::X])) {
665 snap_dim = GUIDE_TRANSL_SNAP_X;
666 } else {
667 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
668 }
670 // We don't support ANGLED_GUIDE_ROT_SNAP yet.
672 // It would be cool to allow the user to rotate a guide by dragging it, instead of
673 // only translating it. (For example when CTRL is pressed). We will need an UI part
674 // for that first; and some important usability choices need to be made:
675 // E.g. which point should be used for pivoting? A previously snapped point,
676 // or a transformation center (which can be moved after clicking for the
677 // second time on an object; but should this point then be constrained to the
678 // line, or can it be located anywhere?)
680 _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), snap_dim, false, Geom::identity());
681 _snapTranslatingGuideToNodes(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, guide_normal);
682 // _snapRotatingGuideToNodes has not been implemented yet.
683 }
685 /**
686 * \return true if this Snapper will snap at least one kind of point.
687 */
688 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
689 {
690 bool snap_to_something = _snap_to_itempath || _snap_to_itemnode || _snap_to_bboxpath || _snap_to_bboxnode || _snap_to_page_border;
691 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeBBoxOrNodes() && snap_to_something);
692 }
694 bool Inkscape::ObjectSnapper::GuidesMightSnap() const
695 {
696 bool snap_to_something = _snap_to_itemnode || _snap_to_bboxnode;
697 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeGuide() && snap_to_something);
698 }
700 void Inkscape::ObjectSnapper::_clear_paths() const
701 {
702 for (std::vector<Geom::PathVector*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
703 g_free(*k);
704 }
705 _paths_to_snap_to->clear();
706 }
708 Geom::PathVector* Inkscape::ObjectSnapper::_getBorderPathv() const
709 {
710 Geom::Rect const border_rect = Geom::Rect(Geom::Point(0,0), Geom::Point(sp_document_width(_snapmanager->getDocument()),sp_document_height(_snapmanager->getDocument())));
711 return _getPathvFromRect(border_rect);
712 }
714 Geom::PathVector* Inkscape::ObjectSnapper::_getPathvFromRect(Geom::Rect const rect) const
715 {
716 SPCurve const *border_curve = SPCurve::new_from_rect(rect);
717 if (border_curve) {
718 Geom::PathVector *dummy = new Geom::PathVector(border_curve->get_pathvector());
719 return dummy;
720 } else {
721 return NULL;
722 }
723 }
725 void Inkscape::ObjectSnapper::_getBorderNodes(std::vector<Geom::Point> *points) const
726 {
727 Geom::Coord w = sp_document_width(_snapmanager->getDocument());
728 Geom::Coord h = sp_document_height(_snapmanager->getDocument());
729 points->push_back(Geom::Point(0,0));
730 points->push_back(Geom::Point(0,h));
731 points->push_back(Geom::Point(w,h));
732 points->push_back(Geom::Point(w,0));
733 }
735 void Inkscape::getBBoxPoints(Geom::OptRect const bbox, std::vector<Geom::Point> *points, bool const includeMidpoints)
736 {
737 if (bbox) {
738 // collect the corners of the bounding box
739 for ( unsigned k = 0 ; k < 4 ; k++ ) {
740 points->push_back(bbox->corner(k));
741 // optionally, collect the midpoints of the bounding box's edges too
742 if (includeMidpoints) {
743 points->push_back((bbox->corner(k) + bbox->corner((k+1) % 4))/2);
744 }
745 }
746 }
747 }
749 /*
750 Local Variables:
751 mode:c++
752 c-file-style:"stroustrup"
753 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
754 indent-tabs-mode:nil
755 fill-column:99
756 End:
757 */
758 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :