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 Geom::Matrix transform = Geom::identity();
116 if (item) {
117 SPObject *obj = NULL;
118 if (clip_or_mask) { // If the current item is a clipping path or a mask
119 // then store the transformation of the clipped path or mask itself
120 // but also take into account the additional affine of the object
121 // being clipped / masked
122 transform = to_2geom(item->transform) * additional_affine;
123 } else { // cannot clip or mask more than once
124 // The current item is not a clipping path or a mask, but might
125 // still be the subject of clipping or masking itself ; if so, then
126 // we should also consider that path or mask for snapping to
127 obj = SP_OBJECT(item->clip_ref->getObject());
128 if (obj) {
129 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, item->transform);
130 }
131 obj = SP_OBJECT(item->mask_ref->getObject());
132 if (obj) {
133 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, item->transform);
134 }
135 }
136 }
138 if (SP_IS_GROUP(o)) {
139 _findCandidates(o, it, false, bbox_to_snap, snap_dim, false, Geom::identity());
140 } else {
141 Geom::OptRect bbox_of_item = Geom::Rect();
142 if (clip_or_mask) {
143 // Oh oh, this will get ugly. We cannot use sp_item_i2d_affine directly because we need to
144 // insert an additional transformation in document coordinates (code copied from sp_item_i2d_affine)
145 sp_item_invoke_bbox(item,
146 bbox_of_item,
147 sp_item_i2doc_affine(item) * matrix_to_desktop(additional_affine, item),
148 true);
149 } else {
150 sp_item_invoke_bbox(item, bbox_of_item, sp_item_i2d_affine(item), true);
151 }
152 if (bbox_of_item) {
153 // See if the item is within range
154 if (bbox_to_snap_incl.intersects(*bbox_of_item)) {
155 // This item is within snapping range, so record it as a candidate
156 _candidates->push_back(SnapCandidate(item, clip_or_mask, additional_affine));
157 }
158 }
159 }
160 }
161 }
162 }
163 }
166 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::SnapPreferences::PointType const &t,
167 bool const &first_point) const
168 {
169 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
170 // e.g. when translating an item using the selector tool, then we will only do this for the
171 // first point and store the collection for later use. This significantly improves the performance
172 if (first_point) {
173 _points_to_snap_to->clear();
175 // Determine the type of bounding box we should snap to
176 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
178 bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
179 bool p_is_a_bbox = t & Inkscape::SnapPreferences::SNAPPOINT_BBOX;
180 bool p_is_a_guide = t & Inkscape::SnapPreferences::SNAPPOINT_GUIDE;
182 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
183 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)));
185 if (_snap_to_bboxnode) {
186 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
187 bool prefs_bbox = prefs->getBool("/tools/bounding_box");
188 bbox_type = !prefs_bbox ?
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 // Note: there are two ways in which intersections are considered:
209 // Method 1: Intersections are calculated for each shape individually, for both the
210 // snap source and snap target (see sp_shape_snappoints)
211 // Method 2: Intersections are calculated for each curve or line that we've snapped to, i.e. only for
212 // the target (see the intersect() method in the SnappedCurve and SnappedLine classes)
213 // Some differences:
214 // - Method 1 doesn't find intersections within a set of multiple objects
215 // - Method 2 only works for targets
216 // When considering intersections as snap targets:
217 // - Method 1 only works when snapping to nodes, whereas
218 // - Method 2 only works when snapping to paths
219 // - There will be performance differences too!
220 // If both methods are being used simultaneously, then this might lead to duplicate targets!
222 // Well, here we will be looking for snap TARGETS. Both methods can therefore be used.
223 // When snapping to paths, we will get a collection of snapped lines and snapped curves. findBestSnap() will
224 // go hunting for intersections (but only when asked to in the prefs of course). In that case we can just
225 // temporarily block the intersections in sp_item_snappoints, we don't need duplicates. If we're not snapping to
226 // paths though but only to item nodes then we should still look for the intersections in sp_item_snappoints()
227 bool old_pref = _snapmanager->snapprefs.getSnapIntersectionCS();
228 if (_snap_to_itempath) {
229 _snapmanager->snapprefs.setSnapIntersectionCS(false);
230 }
232 sp_item_snappoints(root_item, SnapPointsIter(*_points_to_snap_to), &_snapmanager->snapprefs);
234 if (_snap_to_itempath) {
235 _snapmanager->snapprefs.setSnapIntersectionCS(old_pref);
236 }
237 }
238 }
240 //Collect the bounding box's corners so we can snap to them
241 if (_snap_to_bboxnode) {
242 if (!(_strict_snapping && !p_is_a_bbox) || p_is_a_guide) {
243 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
244 // of the item AND the bbox of the clipping path at the same time
245 if (!(*i).clip_or_mask) {
246 Geom::OptRect b = sp_item_bbox_desktop(root_item, bbox_type);
247 if (b) {
248 for ( unsigned k = 0 ; k < 4 ; k++ ) {
249 _points_to_snap_to->push_back(b->corner(k));
250 }
251 }
252 }
253 }
254 }
255 }
256 }
257 }
259 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
260 Inkscape::SnapPreferences::PointType const &t,
261 Geom::Point const &p,
262 bool const &first_point,
263 std::vector<Geom::Point> *unselected_nodes) const
264 {
265 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
267 _collectNodes(t, first_point);
269 if (unselected_nodes != NULL) {
270 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
271 }
273 SnappedPoint s;
274 bool success = false;
276 for (std::vector<Geom::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
277 Geom::Coord dist = Geom::L2(*k - p);
278 if (dist < getSnapperTolerance() && dist < s.getSnapDistance()) {
279 s = SnappedPoint(*k, SNAPTARGET_NODE, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
280 success = true;
281 }
282 }
284 if (success) {
285 sc.points.push_back(s);
286 }
287 }
289 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
290 Inkscape::SnapPreferences::PointType const &t,
291 Geom::Point const &p,
292 Geom::Point const &guide_normal) const
293 {
294 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
295 _collectNodes(t, true);
297 SnappedPoint s;
298 bool success = false;
300 Geom::Coord tol = getSnapperTolerance();
302 for (std::vector<Geom::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
303 // Project each node (*k) on the guide line (running through point p)
304 Geom::Point p_proj = project_on_linesegment(*k, p, p + Geom::rot90(guide_normal));
305 Geom::Coord dist = Geom::L2(*k - p_proj); // distance from node to the guide
306 Geom::Coord dist2 = Geom::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
307 if ((dist < tol && dist2 < tol) || (getSnapperAlwaysSnap() && dist < s.getSnapDistance())) {
308 s = SnappedPoint(*k, SNAPTARGET_NODE, dist, tol, getSnapperAlwaysSnap(), true);
309 success = true;
310 }
311 }
313 if (success) {
314 sc.points.push_back(s);
315 }
316 }
319 /**
320 * Returns index of first NR_END bpath in array.
321 */
323 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::SnapPreferences::PointType const &t,
324 bool const &first_point) const
325 {
326 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
327 // e.g. when translating an item using the selector tool, then we will only do this for the
328 // first point and store the collection for later use. This significantly improves the performance
329 if (first_point) {
330 _clear_paths();
332 // Determine the type of bounding box we should snap to
333 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
335 bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
337 if (_snap_to_bboxpath) {
338 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
339 int prefs_bbox = prefs->getBool("/tools/bounding_box", 0);
340 bbox_type = !prefs_bbox ?
341 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
342 }
344 // Consider the page border for snapping
345 if (_snap_to_page_border) {
346 Geom::PathVector *border_path = _getBorderPathv();
347 if (border_path != NULL) {
348 _paths_to_snap_to->push_back(border_path);
349 }
350 }
352 for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
354 /* Transform the requested snap point to this item's coordinates */
355 Geom::Matrix i2doc(Geom::identity());
356 SPItem *root_item = NULL;
357 /* We might have a clone at hand, so make sure we get the root item */
358 if (SP_IS_USE((*i).item)) {
359 i2doc = sp_use_get_root_transform(SP_USE((*i).item));
360 root_item = sp_use_root(SP_USE((*i).item));
361 g_return_if_fail(root_item);
362 } else {
363 i2doc = sp_item_i2doc_affine((*i).item);
364 root_item = (*i).item;
365 }
367 //Build a list of all paths considered for snapping to
369 //Add the item's path to snap to
370 if (_snap_to_itempath) {
371 if (!(_strict_snapping && !p_is_a_node)) {
372 // Snapping to the path of characters is very cool, but for a large
373 // chunk of text this will take ages! So limit snapping to text paths
374 // containing max. 240 characters. Snapping the bbox will not be affected
375 bool very_lenghty_prose = false;
376 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
377 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
378 }
379 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
380 // which corresponds to a lag of 500 msec. This is for snapping a rect
381 // to a single line of text.
383 // Snapping for example to a traced bitmap is also very stressing for
384 // the CPU, so we'll only snap to paths having no more than 500 nodes
385 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
386 bool very_complex_path = false;
387 if (SP_IS_PATH(root_item)) {
388 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
389 }
391 if (!very_lenghty_prose && !very_complex_path) {
392 SPCurve *curve = curve_for_item(root_item);
393 if (curve) {
394 // We will get our own copy of the path, which must be freed at some point
395 Geom::PathVector *borderpathv = pathvector_for_curve(root_item, curve, true, true, Geom::identity(), (*i).additional_affine);
396 _paths_to_snap_to->push_back(borderpathv); // Perhaps for speed, get a reference to the Geom::pathvector, and store the transformation besides it.
397 curve->unref();
398 }
399 }
400 }
401 }
403 //Add the item's bounding box to snap to
404 if (_snap_to_bboxpath) {
405 if (!(_strict_snapping && p_is_a_node)) {
406 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
407 // of the item AND the bbox of the clipping path at the same time
408 if (!(*i).clip_or_mask) {
409 Geom::OptRect rect;
410 sp_item_invoke_bbox(root_item, rect, i2doc, TRUE, bbox_type);
411 if (rect) {
412 Geom::PathVector *path = _getPathvFromRect(*rect);
413 _paths_to_snap_to->push_back(path);
414 }
415 }
416 }
417 }
418 }
419 }
420 }
422 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
423 Inkscape::SnapPreferences::PointType const &t,
424 Geom::Point const &p,
425 bool const &first_point,
426 std::vector<Geom::Point> *unselected_nodes,
427 SPPath const *selected_path) const
428 {
429 _collectPaths(t, first_point);
430 // Now we can finally do the real snapping, using the paths collected above
432 g_assert(_snapmanager->getDesktop() != NULL);
433 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p);
435 bool const node_tool_active = _snap_to_itempath && selected_path != NULL;
437 if (first_point) {
438 /* findCandidates() is used for snapping to both paths and nodes. It ignores the path that is
439 * currently being edited, because that path requires special care: when snapping to nodes
440 * only the unselected nodes of that path should be considered, and these will be passed on separately.
441 * This path must not be ignored however when snapping to the paths, so we add it here
442 * manually when applicable.
443 *
444 * Note that this path must be the last in line!
445 * */
446 if (node_tool_active) {
447 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
448 if (curve) {
449 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
450 _paths_to_snap_to->push_back(pathv);
451 curve->unref();
452 }
453 }
454 }
456 for (std::vector<Geom::PathVector*>::const_iterator it_p = _paths_to_snap_to->begin(); it_p != _paths_to_snap_to->end(); it_p++) {
457 bool const being_edited = (node_tool_active && (*it_p) == _paths_to_snap_to->back());
458 //if true then this pathvector it_pv is currently being edited in the node tool
460 // char * svgd = sp_svg_write_path(**it_p);
461 // std::cout << "Dumping the pathvector: " << svgd << std::endl;
463 for(Geom::PathVector::iterator it_pv = (*it_p)->begin(); it_pv != (*it_p)->end(); ++it_pv) {
464 // Find a nearest point for each curve within this path
465 // n curves will return n time values with 0 <= t <= 1
466 std::vector<double> anp = (*it_pv).nearestPointPerCurve(p_doc);
468 std::vector<double>::const_iterator np = anp.begin();
469 unsigned int index = 0;
470 for (; np != anp.end(); np++, index++) {
471 Geom::Curve const *curve = &((*it_pv).at_index(index));
472 Geom::Point const sp_doc = curve->pointAt(*np);
474 bool c1 = true;
475 bool c2 = true;
476 if (being_edited) {
477 /* If the path is being edited, then we should only snap though to stationary pieces of the path
478 * and not to the pieces that are being dragged around. This way we avoid
479 * self-snapping. For this we check whether the nodes at both ends of the current
480 * piece are unselected; if they are then this piece must be stationary
481 */
482 g_assert(unselected_nodes != NULL);
483 Geom::Point start_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(0));
484 Geom::Point end_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(1));
485 c1 = isUnselectedNode(start_pt, unselected_nodes);
486 c2 = isUnselectedNode(end_pt, unselected_nodes);
487 /* Unfortunately, this might yield false positives for coincident nodes. Inkscape might therefore mistakenly
488 * snap to path segments that are not stationary. There are at least two possible ways to overcome this:
489 * - Linking the individual nodes of the SPPath we have here, to the nodes of the NodePath::SubPath class as being
490 * used in sp_nodepath_selected_nodes_move. This class has a member variable called "selected". For this the nodes
491 * should be in the exact same order for both classes, so we can index them
492 * - Replacing the SPPath being used here by the the NodePath::SubPath class; but how?
493 */
494 }
496 Geom::Point const sp_dt = _snapmanager->getDesktop()->doc2dt(sp_doc);
497 if (!being_edited || (c1 && c2)) {
498 Geom::Coord const dist = Geom::distance(sp_doc, p_doc);
499 if (dist < getSnapperTolerance()) {
500 sc.curves.push_back(Inkscape::SnappedCurve(from_2geom(sp_dt), dist, getSnapperTolerance(), getSnapperAlwaysSnap(), false, curve));
501 }
502 }
503 }
504 } // End of: for (Geom::PathVector::iterator ....)
505 }
506 }
508 /* Returns true if point is coincident with one of the unselected nodes */
509 bool Inkscape::ObjectSnapper::isUnselectedNode(Geom::Point const &point, std::vector<Geom::Point> const *unselected_nodes) const
510 {
511 if (unselected_nodes == NULL) {
512 return false;
513 }
515 if (unselected_nodes->size() == 0) {
516 return false;
517 }
519 for (std::vector<Geom::Point>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
520 if (Geom::L2(point - *i) < 1e-4) {
521 return true;
522 }
523 }
525 return false;
526 }
528 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
529 Inkscape::SnapPreferences::PointType const &t,
530 Geom::Point const &p,
531 bool const &first_point,
532 ConstraintLine const &c) const
533 {
535 _collectPaths(t, first_point);
537 // Now we can finally do the real snapping, using the paths collected above
539 g_assert(_snapmanager->getDesktop() != NULL);
540 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p);
542 Geom::Point direction_vector = c.getDirection();
543 if (!is_zero(direction_vector)) {
544 direction_vector = Geom::unit_vector(direction_vector);
545 }
547 Geom::Point const p1_on_cl = c.hasPoint() ? c.getPoint() : p;
548 Geom::Point const p2_on_cl = p1_on_cl + direction_vector;
550 // The intersection point of the constraint line with any path,
551 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
552 // The distance between those points is twice the snapping tolerance
553 Geom::Point const p_proj_on_cl = project_on_linesegment(p, p1_on_cl, p2_on_cl);
554 Geom::Point const p_min_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
555 Geom::Point const p_max_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
557 Geom::Path cl;
558 std::vector<Geom::Path> clv;
559 cl.start(p_min_on_cl);
560 cl.appendNew<Geom::LineSegment>(p_max_on_cl);
561 clv.push_back(cl);
563 for (std::vector<Geom::PathVector*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
564 if (*k) {
565 Geom::CrossingSet cs = Geom::crossings(clv, *(*k));
566 if (cs.size() > 0) {
567 // We need only the first element of cs, because cl is only a single straight linesegment
568 // This first element contains a vector filled with crossings of cl with *k
569 for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
570 if ((*m).ta >= 0 && (*m).ta <= 1 ) {
571 // Reconstruct the point of intersection
572 Geom::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
573 // When it's within snapping range, then return it
574 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
575 Geom::Coord dist = Geom::L2(_snapmanager->getDesktop()->dt2doc(p_proj_on_cl) - p_inters);
576 SnappedPoint s(_snapmanager->getDesktop()->doc2dt(p_inters), SNAPTARGET_PATH, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
577 sc.points.push_back(s);
578 }
579 }
580 }
581 }
582 }
583 }
586 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
587 Inkscape::SnapPreferences::PointType const &t,
588 Geom::Point const &p,
589 bool const &first_point,
590 Geom::OptRect const &bbox_to_snap,
591 std::vector<SPItem const *> const *it,
592 std::vector<Geom::Point> *unselected_nodes) const
593 {
594 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false ) {
595 return;
596 }
598 /* Get a list of all the SPItems that we will try to snap to */
599 if (first_point) {
600 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
601 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
602 }
604 if (_snap_to_itemnode || _snap_to_bboxnode || _snap_to_page_border) {
605 _snapNodes(sc, t, p, first_point, unselected_nodes);
606 }
608 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
609 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
610 if (n > 0) {
611 /* While editing a path in the node tool, findCandidates must ignore that path because
612 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
613 * That path must not be ignored however when snapping to the paths, so we add it here
614 * manually when applicable
615 */
616 SPPath *path = NULL;
617 if (it != NULL) {
618 g_assert(SP_IS_PATH(*it->begin()));
619 g_assert(it->size() == 1);
620 path = SP_PATH(*it->begin());
621 }
622 _snapPaths(sc, t, p, first_point, unselected_nodes, path);
623 } else {
624 _snapPaths(sc, t, p, first_point, NULL, NULL);
625 }
626 }
627 }
629 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
630 Inkscape::SnapPreferences::PointType const &t,
631 Geom::Point const &p,
632 bool const &first_point,
633 Geom::OptRect const &bbox_to_snap,
634 ConstraintLine const &c,
635 std::vector<SPItem const *> const *it) const
636 {
637 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false) {
638 return;
639 }
641 /* Get a list of all the SPItems that we will try to snap to */
642 if (first_point) {
643 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
644 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
645 }
647 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
648 // This is usefull for example when scaling an object while maintaining a fixed aspect ratio. It's
649 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
651 // When snapping to objects, we either snap to their nodes or their paths. It is however very
652 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
653 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
654 // so we will more or less snap to them anyhow.
656 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
657 _snapPathsConstrained(sc, t, p, first_point, c);
658 }
659 }
662 // This method is used to snap a guide to nodes, while dragging the guide around
663 void Inkscape::ObjectSnapper::guideSnap(SnappedConstraints &sc,
664 Geom::Point const &p,
665 Geom::Point const &guide_normal) const
666 {
667 /* Get a list of all the SPItems that we will try to snap to */
668 std::vector<SPItem*> cand;
669 std::vector<SPItem const *> const it; //just an empty list
671 DimensionToSnap snap_dim;
672 if (guide_normal == to_2geom(component_vectors[Geom::Y])) {
673 snap_dim = GUIDE_TRANSL_SNAP_Y;
674 } else if (guide_normal == to_2geom(component_vectors[Geom::X])) {
675 snap_dim = GUIDE_TRANSL_SNAP_X;
676 } else {
677 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
678 }
680 // We don't support ANGLED_GUIDE_ROT_SNAP yet.
682 // It would be cool to allow the user to rotate a guide by dragging it, instead of
683 // only translating it. (For example when CTRL is pressed). We will need an UI part
684 // for that first; and some important usability choices need to be made:
685 // E.g. which point should be used for pivoting? A previously snapped point,
686 // or a transformation center (which can be moved after clicking for the
687 // second time on an object; but should this point then be constrained to the
688 // line, or can it be located anywhere?)
690 _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), snap_dim, false, Geom::identity());
691 _snapTranslatingGuideToNodes(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, guide_normal);
692 // _snapRotatingGuideToNodes has not been implemented yet.
693 }
695 /**
696 * \return true if this Snapper will snap at least one kind of point.
697 */
698 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
699 {
700 bool snap_to_something = _snap_to_itempath || _snap_to_itemnode || _snap_to_bboxpath || _snap_to_bboxnode || _snap_to_page_border;
701 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeBBoxOrNodes() && snap_to_something);
702 }
704 bool Inkscape::ObjectSnapper::GuidesMightSnap() const
705 {
706 bool snap_to_something = _snap_to_itemnode || _snap_to_bboxnode;
707 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeGuide() && snap_to_something);
708 }
710 void Inkscape::ObjectSnapper::_clear_paths() const
711 {
712 for (std::vector<Geom::PathVector*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
713 g_free(*k);
714 }
715 _paths_to_snap_to->clear();
716 }
718 Geom::PathVector* Inkscape::ObjectSnapper::_getBorderPathv() const
719 {
720 Geom::Rect const border_rect = Geom::Rect(Geom::Point(0,0), Geom::Point(sp_document_width(_snapmanager->getDocument()),sp_document_height(_snapmanager->getDocument())));
721 return _getPathvFromRect(border_rect);
722 }
724 Geom::PathVector* Inkscape::ObjectSnapper::_getPathvFromRect(Geom::Rect const rect) const
725 {
726 SPCurve const *border_curve = SPCurve::new_from_rect(rect);
727 if (border_curve) {
728 Geom::PathVector *dummy = new Geom::PathVector(border_curve->get_pathvector());
729 return dummy;
730 } else {
731 return NULL;
732 }
733 }
735 void Inkscape::ObjectSnapper::_getBorderNodes(std::vector<Geom::Point> *points) const
736 {
737 Geom::Coord w = sp_document_width(_snapmanager->getDocument());
738 Geom::Coord h = sp_document_height(_snapmanager->getDocument());
739 points->push_back(Geom::Point(0,0));
740 points->push_back(Geom::Point(0,h));
741 points->push_back(Geom::Point(w,h));
742 points->push_back(Geom::Point(w,0));
743 }
745 /*
746 Local Variables:
747 mode:c++
748 c-file-style:"stroustrup"
749 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
750 indent-tabs-mode:nil
751 fill-column:99
752 End:
753 */
754 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :