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 "libnr/n-art-bpath.h"
15 #include "libnr/nr-path.h"
16 #include "libnr/nr-rect-ops.h"
17 #include "libnr/nr-point-fns.h"
18 #include "libnr/n-art-bpath-2geom.h"
19 #include "2geom/path-intersection.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 "desktop.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"
34 Inkscape::ObjectSnapper::ObjectSnapper(SPNamedView const *nv, NR::Coord const d)
35 : Snapper(nv, d), _snap_to_itemnode(true), _snap_to_itempath(true),
36 _snap_to_bboxnode(true), _snap_to_bboxpath(true), _snap_to_page_border(false),
37 _strict_snapping(true), _include_item_center(false)
38 {
39 _candidates = new std::vector<SPItem*>;
40 _points_to_snap_to = new std::vector<NR::Point>;
41 _bpaths_to_snap_to = new std::vector<NArtBpath*>;
42 _paths_to_snap_to = new std::vector<Path*>;
43 }
45 Inkscape::ObjectSnapper::~ObjectSnapper()
46 {
47 _candidates->clear(); //Don't delete the candidates themselves, as these are not ours!
48 delete _candidates;
50 _points_to_snap_to->clear();
51 delete _points_to_snap_to;
53 _clear_paths();
54 delete _paths_to_snap_to;
55 delete _bpaths_to_snap_to;
56 }
58 /**
59 * Find all items within snapping range.
60 * \param r Pointer to the current document
61 * \param it List of items to ignore
62 * \param first_point If true then this point is the first one from a whole bunch of points
63 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
64 * \param DimensionToSnap Snap in X, Y, or both directions.
65 */
67 void Inkscape::ObjectSnapper::_findCandidates(SPObject* r,
68 std::vector<SPItem const *> const &it,
69 bool const &first_point,
70 std::vector<NR::Point> &points_to_snap,
71 DimensionToSnap const snap_dim) const
72 {
73 bool const c1 = (snap_dim == TRANSL_SNAP_XY) && ThisSnapperMightSnap();
74 bool const c2 = (snap_dim != TRANSL_SNAP_XY) && GuidesMightSnap();
75 bool const c3 = points_to_snap.size() == 0;
77 if (!(c1 || c2) || c3) {
78 return;
79 }
81 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
83 if (first_point) {
84 _candidates->clear();
85 }
87 NR::Maybe<NR::Rect> bbox = NR::Rect(); // a default NR::Rect is infinitely large
88 NR::Coord t = getSnapperTolerance();
90 // When dragging a guide...
91 NR::Point p_guide = points_to_snap[0];
92 if (!getSnapperAlwaysSnap()) {
93 bbox = NR::Rect(p_guide, p_guide); // bbox is now just a single point: p_guide
94 bbox->growBy(t); // bbox width and height now measure 2x snapper tolerance
95 // for angled guidelines the bbox is now larger than really needed
96 // (up to sqrt(2) for 45 deg. guidelines) but we'll leave it like that
97 } // else: use an infinitely large bbox to find candidates
99 for (SPObject* o = sp_object_first_child(r); o != NULL; o = SP_OBJECT_NEXT(o)) {
100 if (SP_IS_ITEM(o) && !SP_ITEM(o)->isLocked() && !desktop->itemIsHidden(SP_ITEM(o))) {
102 /* See if this item is on the ignore list */
103 std::vector<SPItem const *>::const_iterator i = it.begin();
104 while (i != it.end() && *i != o) {
105 i++;
106 }
108 if (i == it.end()) {
109 /* See if the item is within range */
110 if (SP_IS_GROUP(o)) {
111 _findCandidates(o, it, false, points_to_snap, snap_dim);
112 } else {
113 // Now let's see if any of the snapping points is within snapping range of this object
114 if (snap_dim == TRANSL_SNAP_XY) {
115 bbox = sp_item_bbox_desktop(SP_ITEM(o));
116 } // else: we're snapping a guide to an object and we will use the bbox as defined above
118 if (bbox) {
119 for (std::vector<NR::Point>::const_iterator i = points_to_snap.begin(); i != points_to_snap.end(); i++) {
120 NR::Point b_min = bbox->min();
121 NR::Point b_max = bbox->max();
122 bool withinX = ((*i)[NR::X] >= b_min[NR::X] - t) && ((*i)[NR::X] <= b_max[NR::X] + t);
123 bool withinY = ((*i)[NR::Y] >= b_min[NR::Y] - t) && ((*i)[NR::Y] <= b_max[NR::Y] + t);
124 if (withinX && withinY) {
125 //We've found a point that is within snapping range
126 //of this object, so record it as a candidate
127 _candidates->push_back(SP_ITEM(o));
128 break;
129 }
130 }
131 }
132 }
133 }
134 }
135 }
136 }
139 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::Snapper::PointType const &t,
140 bool const &first_point) const
141 {
142 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
143 // e.g. when translating an item using the selector tool, then we will only do this for the
144 // first point and store the collection for later use. This significantly improves the performance
145 if (first_point) {
146 _points_to_snap_to->clear();
148 // Determine the type of bounding box we should snap to
149 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
151 bool p_is_a_node = t & Inkscape::Snapper::SNAPPOINT_NODE;
152 bool p_is_a_bbox = t & Inkscape::Snapper::SNAPPOINT_BBOX;
153 bool p_is_a_guide = t & Inkscape::Snapper::SNAPPOINT_GUIDE;
155 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
156 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));
158 if (_snap_to_bboxnode) {
159 int prefs_bbox = prefs_get_int_attribute("tools", "bounding_box", 0);
160 bbox_type = (prefs_bbox ==0)?
161 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
162 }
164 for (std::vector<SPItem*>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
165 //NR::Matrix i2doc(NR::identity());
166 SPItem *root_item = *i;
167 if (SP_IS_USE(*i)) {
168 root_item = sp_use_root(SP_USE(*i));
169 }
170 g_return_if_fail(root_item);
172 //Collect all nodes so we can snap to them
173 if (_snap_to_itemnode) {
174 if (!(_strict_snapping && !p_is_a_node) || p_is_a_guide) {
175 sp_item_snappoints(root_item, _include_item_center, SnapPointsIter(*_points_to_snap_to));
176 }
177 }
179 //Collect the bounding box's corners so we can snap to them
180 if (_snap_to_bboxnode) {
181 if (!(_strict_snapping && !p_is_a_bbox) || p_is_a_guide) {
182 NR::Maybe<NR::Rect> b = sp_item_bbox_desktop(root_item, bbox_type);
183 if (b) {
184 for ( unsigned k = 0 ; k < 4 ; k++ ) {
185 _points_to_snap_to->push_back(b->corner(k));
186 }
187 }
188 }
189 }
190 }
191 }
192 }
194 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
195 Inkscape::Snapper::PointType const &t,
196 NR::Point const &p,
197 bool const &first_point,
198 std::vector<NR::Point> *unselected_nodes) const
199 {
200 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
202 _collectNodes(t, first_point);
204 if (unselected_nodes != NULL) {
205 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
206 }
208 SnappedPoint s;
209 bool success = false;
211 for (std::vector<NR::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
212 NR::Coord dist = NR::L2(*k - p);
213 if (dist < getSnapperTolerance() && dist < s.getDistance()) {
214 s = SnappedPoint(*k, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
215 success = true;
216 }
217 }
219 if (success) {
220 sc.points.push_back(s);
221 }
222 }
224 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
225 Inkscape::Snapper::PointType const &t,
226 NR::Point const &p,
227 NR::Point const &guide_normal) const
228 {
229 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
230 _collectNodes(t, true);
232 SnappedPoint s;
233 bool success = false;
235 NR::Coord tol = getSnapperTolerance();
237 for (std::vector<NR::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
238 // Project each node (*k) on the guide line (running through point p)
239 NR::Point p_proj = project_on_linesegment(*k, p, p + NR::rot90(guide_normal));
240 NR::Coord dist = NR::L2(*k - p_proj); // distance from node to the guide
241 NR::Coord dist2 = NR::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
242 if ((dist < tol && dist2 < tol || getSnapperAlwaysSnap()) && dist < s.getDistance()) {
243 s = SnappedPoint(*k, dist, tol, getSnapperAlwaysSnap());
244 success = true;
245 }
246 }
248 if (success) {
249 sc.points.push_back(s);
250 }
251 }
253 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::Snapper::PointType const &t,
254 bool const &first_point,
255 NArtBpath *border_bpath) const
256 {
257 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
258 // e.g. when translating an item using the selector tool, then we will only do this for the
259 // first point and store the collection for later use. This significantly improves the performance
260 if (first_point) {
261 _clear_paths();
263 // Determine the type of bounding box we should snap to
264 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
266 bool p_is_a_node = t & Inkscape::Snapper::SNAPPOINT_NODE;
268 if (_snap_to_bboxpath) {
269 int prefs_bbox = prefs_get_int_attribute("tools", "bounding_box", 0);
270 bbox_type = (prefs_bbox ==0)?
271 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
272 }
274 // Consider the page border for snapping
275 if (border_bpath != NULL) {
276 _bpaths_to_snap_to->push_back(border_bpath);
277 }
279 for (std::vector<SPItem*>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
281 /* Transform the requested snap point to this item's coordinates */
282 NR::Matrix i2doc(NR::identity());
283 SPItem *root_item = NULL;
284 /* We might have a clone at hand, so make sure we get the root item */
285 if (SP_IS_USE(*i)) {
286 i2doc = sp_use_get_root_transform(SP_USE(*i));
287 root_item = sp_use_root(SP_USE(*i));
288 g_return_if_fail(root_item);
289 } else {
290 i2doc = sp_item_i2doc_affine(*i);
291 root_item = *i;
292 }
294 //Build a list of all paths considered for snapping to
296 //Add the item's path to snap to
297 if (_snap_to_itempath) {
298 if (!(_strict_snapping && !p_is_a_node)) {
299 // Snapping to the path of characters is very cool, but for a large
300 // chunk of text this will take ages! So limit snapping to text paths
301 // containing max. 240 characters. Snapping the bbox will not be affected
302 bool very_lenghty_prose = false;
303 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
304 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
305 }
306 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
307 // which corresponds to a lag of 500 msec. This is for snapping a rect
308 // to a single line of text.
310 // Snapping for example to a traced bitmap is also very stressing for
311 // the CPU, so we'll only snap to paths having no more than 500 nodes
312 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
313 bool very_complex_path = false;
314 if (SP_IS_PATH(root_item)) {
315 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
316 }
318 if (!very_lenghty_prose && !very_complex_path) {
319 SPCurve *curve = curve_for_item(root_item);
320 if (curve) {
321 NArtBpath *bpath = bpath_for_curve(root_item, curve, true, true);
322 _bpaths_to_snap_to->push_back(bpath);
323 // Because we set doTransformation to true in bpath_for_curve, we
324 // will get a dupe of the path, which must be freed at some point
325 sp_curve_unref(curve);
326 }
327 }
328 }
329 }
331 //Add the item's bounding box to snap to
332 if (_snap_to_bboxpath) {
333 if (!(_strict_snapping && p_is_a_node)) {
334 NRRect rect;
335 sp_item_invoke_bbox(root_item, &rect, i2doc, TRUE, bbox_type);
336 NArtBpath *bpath = nr_path_from_rect(rect);
337 _bpaths_to_snap_to->push_back(bpath);
338 }
339 }
340 }
341 }
342 }
344 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
345 Inkscape::Snapper::PointType const &t,
346 NR::Point const &p,
347 bool const &first_point,
348 std::vector<NR::Point> *unselected_nodes,
349 SPPath const *selected_path,
350 NArtBpath *border_bpath) const
351 {
352 _collectPaths(t, first_point, border_bpath);
353 // Now we can finally do the real snapping, using the paths collected above
354 SnappedPoint s;
355 bool success = false;
357 /* FIXME: this seems like a hack. Perhaps Snappers should be
358 ** in SPDesktop rather than SPNamedView?
359 */
360 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
361 NR::Point const p_doc = desktop->dt2doc(p);
363 bool const node_tool_active = _snap_to_itempath && selected_path != NULL;
365 if (first_point) {
366 /* While editing a path in the node tool, findCandidates must ignore that path because
367 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
368 * This path must not be ignored however when snapping to the paths, so we add it here
369 * manually when applicable.
370 *
371 * Note that this path must be the last in line!
372 * */
373 if (node_tool_active) {
374 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
375 if (curve) {
376 NArtBpath *bpath = bpath_for_curve(SP_ITEM(selected_path), curve, true, true);
377 _bpaths_to_snap_to->push_back(bpath);
378 // Because we set doTransformation to true in bpath_for_curve, we
379 // will get a dupe of the path, which must be freed at some point
380 sp_curve_unref(curve);
381 }
382 }
383 // Convert all bpaths to Paths, because here we really must have Paths
384 // (whereas in _snapPathsConstrained we will use the original bpaths)
385 for (std::vector<NArtBpath*>::const_iterator k = _bpaths_to_snap_to->begin(); k != _bpaths_to_snap_to->end(); k++) {
386 Path *path = bpath_to_Path(*k);
387 if (path) {
388 path->ConvertWithBackData(0.01); //This is extremely time consuming!
389 _paths_to_snap_to->push_back(path);
390 }
391 }
392 }
394 for (std::vector<Path*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
395 if (*k) {
396 bool const being_edited = (node_tool_active && (*k) == _paths_to_snap_to->back());
397 //if true then this path k is currently being edited in the node tool
399 for (unsigned i = 1 ; i < (*k)->pts.size() ; i++) {
400 NR::Point start_point;
401 NR::Point end_point;
402 NR::Maybe<Path::cut_position> o = NR::Nothing();
403 if (being_edited) {
404 /* If the path is being edited, then we will try to snap to each piece of the
405 * path individually. We should only snap though to stationary pieces of the paths
406 * and not to the pieces that are being dragged around. This way we avoid
407 * self-snapping. For this we check whether the nodes at both ends of the current
408 * piece are unselected; if they are then this piece must be stationary
409 */
410 unsigned piece = (*k)->pts[i].piece;
411 // Example: a cubic spline is a single piece within a path; it will be drawn using
412 // a polyline, which is described by the collection of lines between the points pts[i]
413 (*k)->PointAt(piece, 0, start_point);
414 (*k)->PointAt(piece, 1, end_point);
415 start_point = desktop->doc2dt(start_point);
416 end_point = desktop->doc2dt(end_point);
417 g_assert(unselected_nodes != NULL);
418 bool c1 = isUnselectedNode(start_point, unselected_nodes);
419 bool c2 = isUnselectedNode(end_point, unselected_nodes);
420 if (c1 && c2) {
421 o = get_nearest_position_on_Path(*k, p_doc, i);
422 }
423 } else {
424 /* If the path is NOT being edited, then we will try to snap to the path as a
425 * whole, so we need to do this only once and we will break out at the end of
426 * this for-loop iteration */
427 /* Look for the nearest position on this SPItem to our snap point */
428 o = get_nearest_position_on_Path(*k, p_doc);
429 (*k)->PointAt(o->piece, 0, start_point);
430 (*k)->PointAt(o->piece, 1, end_point);
431 start_point = desktop->doc2dt(start_point);
432 end_point = desktop->doc2dt(end_point);
433 }
435 if (o && o->t >= 0 && o->t <= 1) {
436 /* Convert the nearest point back to desktop coordinates */
437 NR::Point const o_it = get_point_on_Path(*k, o->piece, o->t);
438 NR::Point const o_dt = desktop->doc2dt(o_it);
439 NR::Coord const dist = NR::L2(o_dt - p);
441 if (dist < getSnapperTolerance()) {
442 // if we snap to a straight line segment (within a path), then return this line segment
443 if ((*k)->IsLineSegment(o->piece)) {
444 sc.lines.push_back(Inkscape::SnappedLineSegment(o_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), start_point, end_point));
445 } else {
446 // for segments other than straight lines of a path, we'll return just the closest snapped point
447 if (dist < s.getDistance()) {
448 s = SnappedPoint(o_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
449 success = true;
450 }
451 }
452 }
453 }
455 // If the path is NOT being edited, then we will try to snap to the path as a whole
456 // so we need to do this only once
457 if (!being_edited) break;
458 }
459 }
460 }
462 if (success) {
463 sc.points.push_back(s);
464 }
465 }
467 /* Returns true if point is coincident with one of the unselected nodes */
468 bool Inkscape::ObjectSnapper::isUnselectedNode(NR::Point const &point, std::vector<NR::Point> const *unselected_nodes) const
469 {
470 if (unselected_nodes == NULL) {
471 return false;
472 }
474 if (unselected_nodes->size() == 0) {
475 return false;
476 }
478 for (std::vector<NR::Point>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
479 if (NR::L2(point - *i) < 1e-4) {
480 return true;
481 }
482 }
484 return false;
485 }
487 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
488 Inkscape::Snapper::PointType const &t,
489 NR::Point const &p,
490 bool const &first_point,
491 ConstraintLine const &c) const
492 {
494 // Consider the page's border for snapping to
495 NArtBpath *border_bpath = _snap_to_page_border ? _getBorderBPath() : NULL;
497 _collectPaths(t, first_point, border_bpath);
499 // Now we can finally do the real snapping, using the paths collected above
501 /* FIXME: this seems like a hack. Perhaps Snappers should be
502 ** in SPDesktop rather than SPNamedView?
503 */
504 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
505 NR::Point const p_doc = desktop->dt2doc(p);
507 NR::Point direction_vector = c.getDirection();
508 if (!is_zero(direction_vector)) {
509 direction_vector = NR::unit_vector(direction_vector);
510 }
512 NR::Point const p1_on_cl = c.hasPoint() ? c.getPoint() : p;
513 NR::Point const p2_on_cl = p1_on_cl + direction_vector;
515 // The intersection point of the constraint line with any path,
516 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
517 // The distance between those points is twice the snapping tolerance
518 NR::Point const p_proj_on_cl = project_on_linesegment(p, p1_on_cl, p2_on_cl);
519 NR::Point const p_min_on_cl = desktop->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
520 NR::Point const p_max_on_cl = desktop->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
522 Geom::Path cl;
523 cl.start(p_min_on_cl.to_2geom());
524 cl.appendNew<Geom::LineSegment>(p_max_on_cl.to_2geom());
526 for (std::vector<NArtBpath*>::const_iterator k = _bpaths_to_snap_to->begin(); k != _bpaths_to_snap_to->end(); k++) {
527 if (*k) {
528 // convert a Path object (see src/livarot/Path.h) to a 2geom's path object (see 2geom/path.h)
529 // TODO: (Diederik) Only do this once for the first point, needs some storage of pointers in a member variable
530 std::vector<Geom::Path> path_2geom = BPath_to_2GeomPath(*k);
532 for (std::vector<Geom::Path>::const_iterator l = path_2geom.begin(); l != path_2geom.end(); l++) {
533 Geom::SimpleCrosser sxr;
534 Geom::Crossings crossings = sxr.crossings(*l, cl);
535 for (std::vector<Geom::Crossing>::const_iterator m = crossings.begin(); m != crossings.end(); m++) {
536 // Reconstruct the point of intersection
537 NR::Point p_inters = p_min_on_cl + ((*m).tb) * (p_max_on_cl - p_min_on_cl);
538 // When it's within snapping range, then return it
539 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < tb < 1)
540 if ((*m).tb >= 0 && (*m).tb <= 1 ) {
541 NR::Coord dist = NR::L2(desktop->dt2doc(p_proj_on_cl) - p_inters);
542 SnappedPoint s(desktop->doc2dt(p_inters), dist, getSnapperTolerance(), getSnapperAlwaysSnap());
543 sc.points.push_back(s);
544 }
545 }
546 }
547 }
548 }
549 }
552 void Inkscape::ObjectSnapper::_doFreeSnap(SnappedConstraints &sc,
553 Inkscape::Snapper::PointType const &t,
554 NR::Point const &p,
555 bool const &first_point,
556 std::vector<NR::Point> &points_to_snap,
557 std::vector<SPItem const *> const &it,
558 std::vector<NR::Point> *unselected_nodes) const
559 {
560 if ( NULL == _named_view ) {
561 return;
562 }
564 /* Get a list of all the SPItems that we will try to snap to */
565 if (first_point) {
566 _findCandidates(sp_document_root(_named_view->document), it, first_point, points_to_snap, TRANSL_SNAP_XY);
567 }
569 if (_snap_to_itemnode || _snap_to_bboxnode) {
570 _snapNodes(sc, t, p, first_point, unselected_nodes);
571 }
573 // Consider the page's border for snapping to
574 NArtBpath *border_bpath = _snap_to_page_border ? _getBorderBPath() : NULL;
576 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
577 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
578 if (n > 0) {
579 /* While editing a path in the node tool, findCandidates must ignore that path because
580 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
581 * That path must not be ignored however when snapping to the paths, so we add it here
582 * manually when applicable
583 */
584 g_assert(it.size() == 1);
585 g_assert(SP_IS_PATH(*it.begin()));
586 _snapPaths(sc, t, p, first_point, unselected_nodes, SP_PATH(*it.begin()), border_bpath);
587 } else {
588 _snapPaths(sc, t, p, first_point, NULL, NULL, border_bpath);
589 }
590 }
591 }
593 void Inkscape::ObjectSnapper::_doConstrainedSnap( SnappedConstraints &sc,
594 Inkscape::Snapper::PointType const &t,
595 NR::Point const &p,
596 bool const &first_point,
597 std::vector<NR::Point> &points_to_snap,
598 ConstraintLine const &c,
599 std::vector<SPItem const *> const &it) const
600 {
601 if ( NULL == _named_view ) {
602 return;
603 }
605 /* Get a list of all the SPItems that we will try to snap to */
606 if (first_point) {
607 _findCandidates(sp_document_root(_named_view->document), it, first_point, points_to_snap, TRANSL_SNAP_XY);
608 }
610 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
611 // This is usefull for example when scaling an object while maintaining a fixed aspect ratio. It's
612 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
614 // When snapping to objects, we either snap to their nodes or their paths. It is however very
615 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
616 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
617 // so we will more or less snap to them anyhow.
619 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
620 _snapPathsConstrained(sc, t, p, first_point, c);
621 }
622 }
625 // This method is used to snap a guide to nodes, while dragging the guide around
626 void Inkscape::ObjectSnapper::guideSnap(SnappedConstraints &sc,
627 NR::Point const &p,
628 NR::Point const &guide_normal) const
629 {
630 if ( NULL == _named_view ) {
631 return;
632 }
634 /* Get a list of all the SPItems that we will try to snap to */
635 std::vector<SPItem*> cand;
636 std::vector<SPItem const *> const it; //just an empty list
638 std::vector<NR::Point> points_to_snap;
639 points_to_snap.push_back(p);
641 DimensionToSnap snap_dim;
642 if (guide_normal == component_vectors[NR::Y]) {
643 snap_dim = GUIDE_TRANSL_SNAP_Y;
644 } else if (guide_normal == component_vectors[NR::X]) {
645 snap_dim = GUIDE_TRANSL_SNAP_X;
646 } else {
647 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
648 }
649 // We don't support ANGLED_GUIDE_ROT_SNAP yet.
651 // It would be cool to allow the user to rotate a guide by dragging it, instead of
652 // only translating it. (For example when CTRL is pressed). We will need an UI part
653 // for that first; and some important usability choices need to be made:
654 // E.g. which point should be used for pivoting? A previously snapped point,
655 // or a transformation center (which can be moved after clicking for the
656 // second time on an object; but should this point then be constrained to the
657 // line, or can it be located anywhere?)
659 _findCandidates(sp_document_root(_named_view->document), it, true, points_to_snap, snap_dim);
660 _snapTranslatingGuideToNodes(sc, Inkscape::Snapper::SNAPPOINT_GUIDE, p, guide_normal);
662 // _snapRotatingGuideToNodes has not been implemented yet.
663 }
665 /**
666 * \return true if this Snapper will snap at least one kind of point.
667 */
668 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
669 {
670 bool snap_to_something = _snap_to_itempath || _snap_to_itemnode || _snap_to_bboxpath || _snap_to_bboxnode || _snap_to_page_border;
671 return (_snap_enabled && _snap_from != 0 && snap_to_something);
672 }
674 bool Inkscape::ObjectSnapper::GuidesMightSnap() const
675 {
676 bool snap_to_something = _snap_to_itemnode || _snap_to_bboxnode;
677 return (_snap_enabled && (_snap_from & SNAPPOINT_GUIDE) && snap_to_something);
678 }
680 void Inkscape::ObjectSnapper::_clear_paths() const
681 {
682 for (std::vector<NArtBpath*>::const_iterator k = _bpaths_to_snap_to->begin(); k != _bpaths_to_snap_to->end(); k++) {
683 g_free(*k);
684 }
685 _bpaths_to_snap_to->clear();
687 for (std::vector<Path*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
688 delete *k;
689 }
690 _paths_to_snap_to->clear();
691 }
693 NArtBpath* Inkscape::ObjectSnapper::_getBorderBPath() const
694 {
695 NArtBpath *border_bpath = NULL;
696 NR::Rect const border_rect = NR::Rect(NR::Point(0,0), NR::Point(sp_document_width(_named_view->document),sp_document_height(_named_view->document)));
697 SPCurve const *border_curve = sp_curve_new_from_rect(border_rect);
698 if (border_curve) {
699 border_bpath = SP_CURVE_BPATH(border_curve);
700 }
702 return border_bpath;
703 }
704 /*
705 Local Variables:
706 mode:c++
707 c-file-style:"stroustrup"
708 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
709 indent-tabs-mode:nil
710 fill-column:99
711 End:
712 */
713 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :