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 "desktop.h"
29 #include "inkscape.h"
30 #include "prefs-utils.h"
31 #include "sp-text.h"
32 #include "sp-flowtext.h"
33 #include "text-editing.h"
34 #include "sp-clippath.h"
35 #include "sp-mask.h"
36 #include "helper/geom-curves.h"
38 Inkscape::SnapCandidate::SnapCandidate(SPItem* item, bool clip_or_mask, NR::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, NR::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<NR::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 NR::Rect const &bbox_to_snap,
82 DimensionToSnap const snap_dim,
83 bool const clip_or_mask,
84 NR::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 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
95 if (first_point) {
96 _candidates->clear();
97 }
99 boost::optional<NR::Rect> bbox_of_item = NR::Rect(); // a default NR::Rect is infinitely large
100 NR::Rect bbox_to_snap_incl = bbox_to_snap; // _incl means: will include the snapper tolerance
101 bbox_to_snap_incl.growBy(getSnapperTolerance()); // see?
103 for (SPObject* o = sp_object_first_child(parent); o != NULL; o = SP_OBJECT_NEXT(o)) {
104 if (SP_IS_ITEM(o) && !SP_ITEM(o)->isLocked() && !(desktop->itemIsHidden(SP_ITEM(o)) && !clip_or_mask)) {
105 // Don't snap to locked items, and
106 // don't snap to hidden objects, unless they're a clipped path or a mask
107 /* See if this item is on the ignore list */
108 std::vector<SPItem const *>::const_iterator i;
109 if (it != NULL) {
110 i = it->begin();
111 while (i != it->end() && *i != o) {
112 i++;
113 }
114 }
116 if (it == NULL || i == it->end()) {
117 SPItem *item = SP_ITEM(o);
118 NR::Matrix transform = NR::identity();
119 if (item) {
120 SPObject *obj = NULL;
121 if (clip_or_mask) { // If the current item is a clipping path or a mask
122 // then store the transformation of the clipped path or mask itself
123 // but also take into account the additional affine of the object
124 // being clipped / masked
125 transform = item->transform * additional_affine;
126 } else { // cannot clip or mask more than once
127 // The current item is not a clipping path or a mask, but might
128 // still be the subject of clipping or masking itself ; if so, then
129 // we should also consider that path or mask for snapping to
130 obj = SP_OBJECT(item->clip_ref->getObject());
131 if (obj) {
132 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, item->transform);
133 }
134 obj = SP_OBJECT(item->mask_ref->getObject());
135 if (obj) {
136 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, item->transform);
137 }
138 }
139 }
141 if (SP_IS_GROUP(o)) {
142 _findCandidates(o, it, false, bbox_to_snap, snap_dim, false, NR::identity());
143 } else {
144 if (clip_or_mask) {
145 // Oh oh, this will get ugly. We cannot use sp_item_i2d_affine directly because we need to
146 // insert an additional transformation in document coordinates (code copied from sp_item_i2d_affine)
147 sp_item_invoke_bbox(item,
148 &bbox_of_item,
149 from_2geom(sp_item_i2doc_affine(item) * matrix_to_desktop(to_2geom(additional_affine), item)),
150 true);
152 } else {
153 sp_item_invoke_bbox(item, &bbox_of_item, from_2geom(sp_item_i2d_affine(item)), true);
154 }
155 // See if the item is within range
156 if (bbox_of_item) {
157 if (bbox_to_snap_incl.intersects(*bbox_of_item)) {
158 // This item is within snapping range, so record it as a candidate
159 _candidates->push_back(SnapCandidate(item, clip_or_mask, additional_affine));
160 }
161 }
162 }
163 }
164 }
165 }
166 }
169 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::Snapper::PointType const &t,
170 bool const &first_point) const
171 {
172 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
173 // e.g. when translating an item using the selector tool, then we will only do this for the
174 // first point and store the collection for later use. This significantly improves the performance
175 if (first_point) {
176 _points_to_snap_to->clear();
178 // Determine the type of bounding box we should snap to
179 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
181 bool p_is_a_node = t & Inkscape::Snapper::SNAPPOINT_NODE;
182 bool p_is_a_bbox = t & Inkscape::Snapper::SNAPPOINT_BBOX;
183 bool p_is_a_guide = t & Inkscape::Snapper::SNAPPOINT_GUIDE;
185 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
186 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));
188 if (_snap_to_bboxnode) {
189 int prefs_bbox = prefs_get_int_attribute("tools", "bounding_box", 0);
190 bbox_type = (prefs_bbox == 0)?
191 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
192 }
194 // Consider the page border for snapping
195 if (_snap_to_page_border) {
196 _getBorderNodes(_points_to_snap_to);
197 }
199 for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
200 //NR::Matrix i2doc(NR::identity());
201 SPItem *root_item = (*i).item;
202 if (SP_IS_USE((*i).item)) {
203 root_item = sp_use_root(SP_USE((*i).item));
204 }
205 g_return_if_fail(root_item);
207 //Collect all nodes so we can snap to them
208 if (_snap_to_itemnode) {
209 if (!(_strict_snapping && !p_is_a_node) || p_is_a_guide) {
210 sp_item_snappoints(root_item, _include_item_center, SnapPointsIter(*_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(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 NR::Point const &p,
236 bool const &first_point,
237 std::vector<NR::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<NR::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
251 NR::Coord dist = NR::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 NR::Point const &p,
266 NR::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 NR::Coord tol = getSnapperTolerance();
276 for (std::vector<NR::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 NR::Point p_proj = project_on_linesegment(*k, p, p + NR::rot90(guide_normal));
279 NR::Coord dist = NR::L2(*k - p_proj); // distance from node to the guide
280 NR::Coord dist2 = NR::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 NR::Matrix i2doc(NR::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 = from_2geom(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(), to_2geom((*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 NR::Point const &p,
409 bool const &first_point,
410 std::vector<NR::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 /* FIXME: this seems like a hack. Perhaps Snappers should be
417 ** in SPDesktop rather than SPNamedView?
418 */
419 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
420 Geom::Point const p_doc = to_2geom(desktop->dt2doc(p));
422 bool const node_tool_active = _snap_to_itempath && selected_path != NULL;
424 if (first_point) {
425 /* While editing a path in the node tool, findCandidates must ignore that path because
426 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
427 * This path must not be ignored however when snapping to the paths, so we add it here
428 * manually when applicable.
429 *
430 * Note that this path must be the last in line!
431 * */
432 if (node_tool_active) {
433 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
434 if (curve) {
435 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
436 _paths_to_snap_to->push_back(pathv);
437 curve->unref();
438 }
439 }
440 }
442 for (std::vector<Geom::PathVector*>::const_iterator it_p = _paths_to_snap_to->begin(); it_p != _paths_to_snap_to->end(); it_p++) {
443 bool const being_edited = (node_tool_active && (*it_p) == _paths_to_snap_to->back());
445 //if true then this pathvector it_pv is currently being edited in the node tool
446 SnappedPoint s;
447 bool success = false;
449 // char * svgd = sp_svg_write_path(**it_p);
450 // std::cout << "Dumping the pathvector: " << svgd << std::endl;
452 for(Geom::PathVector::iterator it_pv = (*it_p)->begin(); it_pv != (*it_p)->end(); ++it_pv) {
453 std::vector<double> anp;
455 // Find a nearest point for each curve within this path
456 // (path->allNearestPoints() will not do this for us! It was originally
457 // intended to find for example multiple equidistant solutions)
458 unsigned int num_curves = (*it_pv).size();
459 if ( (*it_pv).closed() ) ++num_curves;
460 for (double t = 0; (t+1) <= double(num_curves); t++) {
461 // Find a nearest point with time value in the range [t, t+1]
462 anp.push_back((*it_pv).nearestPoint(p_doc, t, t+1));
463 }
465 for (std::vector<double>::const_iterator np = anp.begin(); np != anp.end(); np++) {
466 bool c1 = true;
467 bool c2 = true;
468 Geom::Point start_pt = desktop->doc2dt((*it_pv).pointAt(floor(*np)));
469 Geom::Point end_pt = desktop->doc2dt((*it_pv).pointAt(ceil(*np)));
471 if (being_edited) {
472 /* If the path is being edited, then we should only snap though to stationary pieces of the path
473 * and not to the pieces that are being dragged around. This way we avoid
474 * self-snapping. For this we check whether the nodes at both ends of the current
475 * piece are unselected; if they are then this piece must be stationary
476 */
477 g_assert(unselected_nodes != NULL);
478 c1 = isUnselectedNode(from_2geom(start_pt), unselected_nodes);
479 c2 = isUnselectedNode(from_2geom(end_pt), unselected_nodes);
480 }
482 Geom::Point const sp_doc = (*it_pv).pointAt(*np);
483 Geom::Point const sp_dt = desktop->doc2dt(sp_doc);
485 if (!being_edited || (c1 && c2)) {
486 NR::Coord const dist = Geom::distance(sp_doc, p_doc);
487 if (dist < getSnapperTolerance()) {
488 double t = MIN(*np, (*it_pv).size()); // make sure that t is within bounds;
489 //Geom::Curve const & curve = (*it_pv).at_index(int(t));
490 if(is_straight_curve((*it_pv).at_index(int(t)))) {
491 // if we snap to a line segment, then return this line segment (leaves 1 DOF for snapping)
492 sc.lines.push_back(Inkscape::SnappedLineSegment(from_2geom(sp_dt), dist, getSnapperTolerance(), getSnapperAlwaysSnap(), from_2geom(start_pt), from_2geom(end_pt)));
493 } else {
494 // for curves other than line segments, we'll return just the closest snapped point
495 // (this is a fully constrained snap, no degrees of freedom left)
496 if (dist < s.getDistance()) {
497 // If this curve has multiple segments, then we will return only
498 // a single snapped point
499 s = SnappedPoint(from_2geom(sp_dt), SNAPTARGET_PATH, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
500 success = true;
501 }
502 }
503 }
504 }
505 }
506 } // End of: for (Geom::PathVector::iterator ....)
508 // Return a snap point for each path in our collection.
509 // (unless we've already snapped to a line segment, see above)
510 if (success) {
511 sc.points.push_back(s);
512 }
514 }
515 }
517 /* Returns true if point is coincident with one of the unselected nodes */
518 bool Inkscape::ObjectSnapper::isUnselectedNode(NR::Point const &point, std::vector<NR::Point> const *unselected_nodes) const
519 {
520 if (unselected_nodes == NULL) {
521 return false;
522 }
524 if (unselected_nodes->size() == 0) {
525 return false;
526 }
528 for (std::vector<NR::Point>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
529 if (NR::L2(point - *i) < 1e-4) {
530 return true;
531 }
532 }
534 return false;
535 }
537 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
538 Inkscape::Snapper::PointType const &t,
539 NR::Point const &p,
540 bool const &first_point,
541 ConstraintLine const &c) const
542 {
544 _collectPaths(t, first_point);
546 // Now we can finally do the real snapping, using the paths collected above
548 /* FIXME: this seems like a hack. Perhaps Snappers should be
549 ** in SPDesktop rather than SPNamedView?
550 */
551 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
552 NR::Point const p_doc = desktop->dt2doc(p);
554 NR::Point direction_vector = c.getDirection();
555 if (!is_zero(direction_vector)) {
556 direction_vector = NR::unit_vector(direction_vector);
557 }
559 NR::Point const p1_on_cl = c.hasPoint() ? c.getPoint() : p;
560 NR::Point const p2_on_cl = p1_on_cl + direction_vector;
562 // The intersection point of the constraint line with any path,
563 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
564 // The distance between those points is twice the snapping tolerance
565 NR::Point const p_proj_on_cl = project_on_linesegment(p, p1_on_cl, p2_on_cl);
566 NR::Point const p_min_on_cl = desktop->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
567 NR::Point const p_max_on_cl = desktop->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
569 Geom::Path cl;
570 std::vector<Geom::Path> clv;
571 cl.start(p_min_on_cl);
572 cl.appendNew<Geom::LineSegment>(p_max_on_cl);
573 clv.push_back(cl);
575 for (std::vector<Geom::PathVector*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
576 if (*k) {
577 Geom::CrossingSet cs = Geom::crossings(clv, *(*k));
578 if (cs.size() > 0) {
579 // We need only the first element of cs, because cl is only a single straight linesegment
580 // This first element contains a vector filled with crossings of cl with *k
581 for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
582 if ((*m).ta >= 0 && (*m).ta <= 1 ) {
583 // Reconstruct the point of intersection
584 NR::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
585 // When it's within snapping range, then return it
586 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
587 NR::Coord dist = NR::L2(desktop->dt2doc(p_proj_on_cl) - p_inters);
588 SnappedPoint s(desktop->doc2dt(p_inters), SNAPTARGET_PATH, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
589 sc.points.push_back(s);
590 }
591 }
592 }
593 }
594 }
595 }
598 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
599 Inkscape::Snapper::PointType const &t,
600 NR::Point const &p,
601 bool const &first_point,
602 boost::optional<NR::Rect> const &bbox_to_snap,
603 std::vector<SPItem const *> const *it,
604 std::vector<NR::Point> *unselected_nodes) const
605 {
606 if (_snap_enabled == false || getSnapFrom(t) == false || _named_view == NULL) {
607 return;
608 }
610 /* Get a list of all the SPItems that we will try to snap to */
611 if (first_point) {
612 NR::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : NR::Rect(p, p);
613 _findCandidates(sp_document_root(_named_view->document), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, NR::identity());
614 }
616 if (_snap_to_itemnode || _snap_to_bboxnode || _snap_to_page_border) {
617 _snapNodes(sc, t, p, first_point, unselected_nodes);
618 }
620 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
621 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
622 if (n > 0) {
623 /* While editing a path in the node tool, findCandidates must ignore that path because
624 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
625 * That path must not be ignored however when snapping to the paths, so we add it here
626 * manually when applicable
627 */
628 SPPath *path = NULL;
629 if (it != NULL) {
630 g_assert(SP_IS_PATH(*it->begin()));
631 g_assert(it->size() == 1);
632 path = SP_PATH(*it->begin());
633 }
634 _snapPaths(sc, t, p, first_point, unselected_nodes, path);
635 } else {
636 _snapPaths(sc, t, p, first_point, NULL, NULL);
637 }
638 }
639 }
641 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
642 Inkscape::Snapper::PointType const &t,
643 NR::Point const &p,
644 bool const &first_point,
645 boost::optional<NR::Rect> const &bbox_to_snap,
646 ConstraintLine const &c,
647 std::vector<SPItem const *> const *it) const
648 {
649 if (_snap_enabled == false || getSnapFrom(t) == false || _named_view == NULL) {
650 return;
651 }
653 /* Get a list of all the SPItems that we will try to snap to */
654 if (first_point) {
655 NR::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : NR::Rect(p, p);
656 _findCandidates(sp_document_root(_named_view->document), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, NR::identity());
657 }
659 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
660 // This is usefull for example when scaling an object while maintaining a fixed aspect ratio. It's
661 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
663 // When snapping to objects, we either snap to their nodes or their paths. It is however very
664 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
665 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
666 // so we will more or less snap to them anyhow.
668 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
669 _snapPathsConstrained(sc, t, p, first_point, c);
670 }
671 }
674 // This method is used to snap a guide to nodes, while dragging the guide around
675 void Inkscape::ObjectSnapper::guideSnap(SnappedConstraints &sc,
676 NR::Point const &p,
677 NR::Point const &guide_normal) const
678 {
679 if ( NULL == _named_view ) {
680 return;
681 }
683 /* Get a list of all the SPItems that we will try to snap to */
684 std::vector<SPItem*> cand;
685 std::vector<SPItem const *> const it; //just an empty list
687 DimensionToSnap snap_dim;
688 if (guide_normal == component_vectors[NR::Y]) {
689 snap_dim = GUIDE_TRANSL_SNAP_Y;
690 } else if (guide_normal == component_vectors[NR::X]) {
691 snap_dim = GUIDE_TRANSL_SNAP_X;
692 } else {
693 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
694 }
696 // We don't support ANGLED_GUIDE_ROT_SNAP yet.
698 // It would be cool to allow the user to rotate a guide by dragging it, instead of
699 // only translating it. (For example when CTRL is pressed). We will need an UI part
700 // for that first; and some important usability choices need to be made:
701 // E.g. which point should be used for pivoting? A previously snapped point,
702 // or a transformation center (which can be moved after clicking for the
703 // second time on an object; but should this point then be constrained to the
704 // line, or can it be located anywhere?)
706 _findCandidates(sp_document_root(_named_view->document), &it, true, NR::Rect(p, p), snap_dim, false, NR::identity());
707 _snapTranslatingGuideToNodes(sc, Inkscape::Snapper::SNAPPOINT_GUIDE, p, guide_normal);
708 // _snapRotatingGuideToNodes has not been implemented yet.
709 }
711 /**
712 * \return true if this Snapper will snap at least one kind of point.
713 */
714 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
715 {
716 bool snap_to_something = _snap_to_itempath || _snap_to_itemnode || _snap_to_bboxpath || _snap_to_bboxnode || _snap_to_page_border;
717 return (_snap_enabled && _snap_from != 0 && snap_to_something);
718 }
720 bool Inkscape::ObjectSnapper::GuidesMightSnap() const
721 {
722 bool snap_to_something = _snap_to_itemnode || _snap_to_bboxnode;
723 return (_snap_enabled && (_snap_from & SNAPPOINT_GUIDE) && snap_to_something);
724 }
726 void Inkscape::ObjectSnapper::_clear_paths() const
727 {
728 for (std::vector<Geom::PathVector*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
729 g_free(*k);
730 }
731 _paths_to_snap_to->clear();
732 }
734 Geom::PathVector* Inkscape::ObjectSnapper::_getBorderPathv() const
735 {
736 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)));
737 return _getPathvFromRect(border_rect);
738 }
740 Geom::PathVector* Inkscape::ObjectSnapper::_getPathvFromRect(Geom::Rect const rect) const
741 {
742 SPCurve const *border_curve = SPCurve::new_from_rect(rect);
743 if (border_curve) {
744 Geom::PathVector *dummy = new Geom::PathVector(border_curve->get_pathvector());
745 return dummy;
746 } else {
747 return NULL;
748 }
749 }
751 void Inkscape::ObjectSnapper::_getBorderNodes(std::vector<NR::Point> *points) const
752 {
753 Geom::Coord w = sp_document_width(_named_view->document);
754 Geom::Coord h = sp_document_height(_named_view->document);
755 points->push_back(from_2geom(Geom::Point(0,0)));
756 points->push_back(from_2geom(Geom::Point(0,h)));
757 points->push_back(from_2geom(Geom::Point(w,h)));
758 points->push_back(from_2geom(Geom::Point(w,0)));
759 }
761 /*
762 Local Variables:
763 mode:c++
764 c-file-style:"stroustrup"
765 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
766 indent-tabs-mode:nil
767 fill-column:99
768 End:
769 */
770 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :