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 bbox_to_snap Bounding box hulling 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 NR::Rect const &bbox_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();
76 if (!(c1 || c2)) {
77 return;
78 }
80 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
82 if (first_point) {
83 _candidates->clear();
84 }
86 NR::Maybe<NR::Rect> bbox_of_item = NR::Rect(); // a default NR::Rect is infinitely large
87 NR::Rect bbox_to_snap_incl = bbox_to_snap; // _incl means: will include the snapper tolerance
88 bbox_to_snap_incl.growBy(getSnapperTolerance()); // see?
90 for (SPObject* o = sp_object_first_child(r); o != NULL; o = SP_OBJECT_NEXT(o)) {
91 if (SP_IS_ITEM(o) && !SP_ITEM(o)->isLocked() && !desktop->itemIsHidden(SP_ITEM(o))) {
93 /* See if this item is on the ignore list */
94 std::vector<SPItem const *>::const_iterator i;
95 if (it != NULL) {
96 i = it->begin();
97 while (i != it->end() && *i != o) {
98 i++;
99 }
100 }
102 if (it == NULL || i == it->end()) {
103 /* See if the item is within range */
104 if (SP_IS_GROUP(o)) {
105 _findCandidates(o, it, false, bbox_to_snap, snap_dim);
106 } else {
107 bbox_of_item = sp_item_bbox_desktop(SP_ITEM(o));
108 if (bbox_of_item) {
109 if (bbox_to_snap_incl.intersects(*bbox_of_item)) {
110 //This item is within snapping range, so record it as a candidate
111 _candidates->push_back(SP_ITEM(o));
112 }
113 }
114 }
115 }
116 }
117 }
118 }
121 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::Snapper::PointType const &t,
122 bool const &first_point) const
123 {
124 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
125 // e.g. when translating an item using the selector tool, then we will only do this for the
126 // first point and store the collection for later use. This significantly improves the performance
127 if (first_point) {
128 _points_to_snap_to->clear();
130 // Determine the type of bounding box we should snap to
131 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
133 bool p_is_a_node = t & Inkscape::Snapper::SNAPPOINT_NODE;
134 bool p_is_a_bbox = t & Inkscape::Snapper::SNAPPOINT_BBOX;
135 bool p_is_a_guide = t & Inkscape::Snapper::SNAPPOINT_GUIDE;
137 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
138 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));
140 if (_snap_to_bboxnode) {
141 int prefs_bbox = prefs_get_int_attribute("tools", "bounding_box", 0);
142 bbox_type = (prefs_bbox ==0)?
143 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
144 }
146 for (std::vector<SPItem*>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
147 //NR::Matrix i2doc(NR::identity());
148 SPItem *root_item = *i;
149 if (SP_IS_USE(*i)) {
150 root_item = sp_use_root(SP_USE(*i));
151 }
152 g_return_if_fail(root_item);
154 //Collect all nodes so we can snap to them
155 if (_snap_to_itemnode) {
156 if (!(_strict_snapping && !p_is_a_node) || p_is_a_guide) {
157 sp_item_snappoints(root_item, _include_item_center, SnapPointsIter(*_points_to_snap_to));
158 }
159 }
161 //Collect the bounding box's corners so we can snap to them
162 if (_snap_to_bboxnode) {
163 if (!(_strict_snapping && !p_is_a_bbox) || p_is_a_guide) {
164 NR::Maybe<NR::Rect> b = sp_item_bbox_desktop(root_item, bbox_type);
165 if (b) {
166 for ( unsigned k = 0 ; k < 4 ; k++ ) {
167 _points_to_snap_to->push_back(b->corner(k));
168 }
169 }
170 }
171 }
172 }
173 }
174 }
176 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
177 Inkscape::Snapper::PointType const &t,
178 NR::Point const &p,
179 bool const &first_point,
180 std::vector<NR::Point> *unselected_nodes) const
181 {
182 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
184 _collectNodes(t, first_point);
186 if (unselected_nodes != NULL) {
187 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
188 }
190 SnappedPoint s;
191 bool success = false;
193 for (std::vector<NR::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
194 NR::Coord dist = NR::L2(*k - p);
195 if (dist < getSnapperTolerance() && dist < s.getDistance()) {
196 s = SnappedPoint(*k, SNAPTARGET_NODE, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
197 success = true;
198 }
199 }
201 if (success) {
202 sc.points.push_back(s);
203 }
204 }
206 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
207 Inkscape::Snapper::PointType const &t,
208 NR::Point const &p,
209 NR::Point const &guide_normal) const
210 {
211 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
212 _collectNodes(t, true);
214 SnappedPoint s;
215 bool success = false;
217 NR::Coord tol = getSnapperTolerance();
219 for (std::vector<NR::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
220 // Project each node (*k) on the guide line (running through point p)
221 NR::Point p_proj = project_on_linesegment(*k, p, p + NR::rot90(guide_normal));
222 NR::Coord dist = NR::L2(*k - p_proj); // distance from node to the guide
223 NR::Coord dist2 = NR::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
224 if ((dist < tol && dist2 < tol || getSnapperAlwaysSnap()) && dist < s.getDistance()) {
225 s = SnappedPoint(*k, SNAPTARGET_NODE, dist, tol, getSnapperAlwaysSnap());
226 success = true;
227 }
228 }
230 if (success) {
231 sc.points.push_back(s);
232 }
233 }
235 /**
236 * Returns index of first NR_END bpath in array.
237 */
238 static unsigned sp_bpath_length(NArtBpath const bpath[])
239 {
240 g_return_val_if_fail(bpath != NULL, FALSE);
241 unsigned ret = 0;
242 while ( bpath[ret].code != NR_END ) {
243 ++ret;
244 }
245 ++ret;
246 return ret;
247 }
249 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::Snapper::PointType const &t,
250 bool const &first_point,
251 NArtBpath const *border_bpath) const
252 {
253 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
254 // e.g. when translating an item using the selector tool, then we will only do this for the
255 // first point and store the collection for later use. This significantly improves the performance
256 if (first_point) {
257 _clear_paths();
259 // Determine the type of bounding box we should snap to
260 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
262 bool p_is_a_node = t & Inkscape::Snapper::SNAPPOINT_NODE;
264 if (_snap_to_bboxpath) {
265 int prefs_bbox = prefs_get_int_attribute("tools", "bounding_box", 0);
266 bbox_type = (prefs_bbox ==0)?
267 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
268 }
270 // Consider the page border for snapping
271 if (border_bpath != NULL) {
272 // make our own copy of the const*
273 NArtBpath *new_bpath;
274 unsigned const len = sp_bpath_length(border_bpath);
275 new_bpath = g_new(NArtBpath, len);
276 memcpy(new_bpath, border_bpath, len * sizeof(NArtBpath));
278 _bpaths_to_snap_to->push_back(new_bpath);
279 }
281 for (std::vector<SPItem*>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
283 /* Transform the requested snap point to this item's coordinates */
284 NR::Matrix i2doc(NR::identity());
285 SPItem *root_item = NULL;
286 /* We might have a clone at hand, so make sure we get the root item */
287 if (SP_IS_USE(*i)) {
288 i2doc = sp_use_get_root_transform(SP_USE(*i));
289 root_item = sp_use_root(SP_USE(*i));
290 g_return_if_fail(root_item);
291 } else {
292 i2doc = sp_item_i2doc_affine(*i);
293 root_item = *i;
294 }
296 //Build a list of all paths considered for snapping to
298 //Add the item's path to snap to
299 if (_snap_to_itempath) {
300 if (!(_strict_snapping && !p_is_a_node)) {
301 // Snapping to the path of characters is very cool, but for a large
302 // chunk of text this will take ages! So limit snapping to text paths
303 // containing max. 240 characters. Snapping the bbox will not be affected
304 bool very_lenghty_prose = false;
305 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
306 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
307 }
308 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
309 // which corresponds to a lag of 500 msec. This is for snapping a rect
310 // to a single line of text.
312 // Snapping for example to a traced bitmap is also very stressing for
313 // the CPU, so we'll only snap to paths having no more than 500 nodes
314 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
315 bool very_complex_path = false;
316 if (SP_IS_PATH(root_item)) {
317 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
318 }
320 if (!very_lenghty_prose && !very_complex_path) {
321 SPCurve *curve = curve_for_item(root_item);
322 if (curve) {
323 NArtBpath *bpath = bpath_for_curve(root_item, curve, true, true);
324 _bpaths_to_snap_to->push_back(bpath);
325 // Because we set doTransformation to true in bpath_for_curve, we
326 // will get a dupe of the path, which must be freed at some point
327 curve->unref();
328 }
329 }
330 }
331 }
333 //Add the item's bounding box to snap to
334 if (_snap_to_bboxpath) {
335 if (!(_strict_snapping && p_is_a_node)) {
336 NRRect rect;
337 sp_item_invoke_bbox(root_item, &rect, i2doc, TRUE, bbox_type);
338 NArtBpath *bpath = nr_path_from_rect(rect);
339 _bpaths_to_snap_to->push_back(bpath);
340 }
341 }
342 }
343 }
344 }
346 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
347 Inkscape::Snapper::PointType const &t,
348 NR::Point const &p,
349 bool const &first_point,
350 std::vector<NR::Point> *unselected_nodes,
351 SPPath const *selected_path,
352 NArtBpath const *border_bpath) const
353 {
354 _collectPaths(t, first_point, border_bpath);
355 // Now we can finally do the real snapping, using the paths collected above
356 SnappedPoint s;
357 bool success = false;
359 /* FIXME: this seems like a hack. Perhaps Snappers should be
360 ** in SPDesktop rather than SPNamedView?
361 */
362 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
363 NR::Point const p_doc = desktop->dt2doc(p);
365 bool const node_tool_active = _snap_to_itempath && selected_path != NULL;
367 if (first_point) {
368 /* While editing a path in the node tool, findCandidates must ignore that path because
369 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
370 * This path must not be ignored however when snapping to the paths, so we add it here
371 * manually when applicable.
372 *
373 * Note that this path must be the last in line!
374 * */
375 if (node_tool_active) {
376 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
377 if (curve) {
378 NArtBpath *bpath = bpath_for_curve(SP_ITEM(selected_path), curve, true, true);
379 _bpaths_to_snap_to->push_back(bpath);
380 // Because we set doTransformation to true in bpath_for_curve, we
381 // will get a dupe of the path, which must be freed at some point
382 curve->unref();
383 }
384 }
385 // Convert all bpaths to Paths, because here we really must have Paths
386 // (whereas in _snapPathsConstrained we will use the original bpaths)
387 for (std::vector<NArtBpath*>::const_iterator k = _bpaths_to_snap_to->begin(); k != _bpaths_to_snap_to->end(); k++) {
388 Path *path = bpath_to_Path(*k);
389 if (path) {
390 path->ConvertWithBackData(0.01); //This is extremely time consuming!
391 _paths_to_snap_to->push_back(path);
392 }
393 }
394 }
396 for (std::vector<Path*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
397 if (*k) {
398 bool const being_edited = (node_tool_active && (*k) == _paths_to_snap_to->back());
399 //if true then this path k is currently being edited in the node tool
401 for (unsigned i = 1 ; i < (*k)->pts.size() ; i++) {
402 //pts describes a polyline approximation, which might consist of 1000s of points!
403 NR::Point start_point;
404 NR::Point end_point;
405 NR::Maybe<Path::cut_position> o = NR::Nothing();
406 if (being_edited) {
407 /* If the path is being edited, then we will try to snap to each piece of the
408 * path individually. We should only snap though to stationary pieces of the paths
409 * and not to the pieces that are being dragged around. This way we avoid
410 * self-snapping. For this we check whether the nodes at both ends of the current
411 * piece are unselected; if they are then this piece must be stationary
412 */
413 unsigned piece = (*k)->pts[i].piece;
414 // Example: a cubic spline is a single piece within a path; it will be drawn using
415 // a polyline, which is described by the collection of lines between the points pts[i]
416 (*k)->PointAt(piece, 0, start_point);
417 (*k)->PointAt(piece, 1, end_point);
418 start_point = desktop->doc2dt(start_point);
419 end_point = desktop->doc2dt(end_point);
420 g_assert(unselected_nodes != NULL);
421 bool c1 = isUnselectedNode(start_point, unselected_nodes);
422 bool c2 = isUnselectedNode(end_point, unselected_nodes);
423 if (c1 && c2) {
424 o = get_nearest_position_on_Path(*k, p_doc, i);
425 }
426 } else {
427 /* If the path is NOT being edited, then we will try to snap to the path as a
428 * whole, so we need to do this only once and we will break out at the end of
429 * this for-loop iteration */
430 /* Look for the nearest position on this SPItem to our snap point */
431 o = get_nearest_position_on_Path(*k, p_doc);
432 (*k)->PointAt(o->piece, 0, start_point);
433 (*k)->PointAt(o->piece, 1, end_point);
434 start_point = desktop->doc2dt(start_point);
435 end_point = desktop->doc2dt(end_point);
436 }
438 if (o && o->t >= 0 && o->t <= 1) {
439 /* Convert the nearest point back to desktop coordinates */
440 NR::Point const o_it = get_point_on_Path(*k, o->piece, o->t);
442 /* IF YOU'RE BUG HUNTING: IT LOOKS LIKE get_point_on_Path SOMETIMES
443 * RETURNS THE WRONG POINT (WITH AN OFFSET, BUT STILL ON THE PATH.
444 * THIS BUG WILL NO LONGER BE ENCOUNTERED ONCE WE'VE SWITCHED TO
445 * 2GEOM FOR THE OBJECT SNAPPER
446 */
448 NR::Point const o_dt = desktop->doc2dt(o_it);
449 NR::Coord const dist = NR::L2(o_dt - p);
451 if (dist < getSnapperTolerance()) {
452 // if we snap to a straight line segment (within a path), then return this line segment
453 if ((*k)->IsLineSegment(o->piece)) {
454 sc.lines.push_back(Inkscape::SnappedLineSegment(o_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), start_point, end_point));
455 } else {
456 // for segments other than straight lines of a path, we'll return just the closest snapped point
457 if (dist < s.getDistance()) {
458 s = SnappedPoint(o_dt, SNAPTARGET_PATH, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
459 success = true;
460 }
461 }
462 }
463 }
465 // If the path is NOT being edited, then we will try to snap to the path as a whole
466 // so we need to do this only once
467 if (!being_edited) break;
468 }
469 }
470 }
472 if (success) {
473 sc.points.push_back(s);
474 }
475 }
477 /* Returns true if point is coincident with one of the unselected nodes */
478 bool Inkscape::ObjectSnapper::isUnselectedNode(NR::Point const &point, std::vector<NR::Point> const *unselected_nodes) const
479 {
480 if (unselected_nodes == NULL) {
481 return false;
482 }
484 if (unselected_nodes->size() == 0) {
485 return false;
486 }
488 for (std::vector<NR::Point>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
489 if (NR::L2(point - *i) < 1e-4) {
490 return true;
491 }
492 }
494 return false;
495 }
497 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
498 Inkscape::Snapper::PointType const &t,
499 NR::Point const &p,
500 bool const &first_point,
501 ConstraintLine const &c) const
502 {
504 // Consider the page's border for snapping to
505 NArtBpath const *border_bpath = _snap_to_page_border ? _getBorderBPath() : NULL;
507 _collectPaths(t, first_point, border_bpath);
509 // Now we can finally do the real snapping, using the paths collected above
511 /* FIXME: this seems like a hack. Perhaps Snappers should be
512 ** in SPDesktop rather than SPNamedView?
513 */
514 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
515 NR::Point const p_doc = desktop->dt2doc(p);
517 NR::Point direction_vector = c.getDirection();
518 if (!is_zero(direction_vector)) {
519 direction_vector = NR::unit_vector(direction_vector);
520 }
522 NR::Point const p1_on_cl = c.hasPoint() ? c.getPoint() : p;
523 NR::Point const p2_on_cl = p1_on_cl + direction_vector;
525 // The intersection point of the constraint line with any path,
526 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
527 // The distance between those points is twice the snapping tolerance
528 NR::Point const p_proj_on_cl = project_on_linesegment(p, p1_on_cl, p2_on_cl);
529 NR::Point const p_min_on_cl = desktop->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
530 NR::Point const p_max_on_cl = desktop->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
532 Geom::Path cl;
533 std::vector<Geom::Path> clv;
534 cl.start(p_min_on_cl.to_2geom());
535 cl.appendNew<Geom::LineSegment>(p_max_on_cl.to_2geom());
536 clv.push_back(cl);
538 for (std::vector<NArtBpath*>::const_iterator k = _bpaths_to_snap_to->begin(); k != _bpaths_to_snap_to->end(); k++) {
539 if (*k) {
540 // convert a Path object (see src/livarot/Path.h) to a 2geom's path object (see 2geom/path.h)
541 // TODO: (Diederik) Only do this once for the first point, needs some storage of pointers in a member variable
542 std::vector<Geom::Path> path_2geom = BPath_to_2GeomPath(*k);
544 Geom::CrossingSet cs = Geom::crossings(clv, path_2geom);
545 if (cs.size() > 0) {
546 // We need only the first element of cs, because cl is only a single straight linesegment
547 // This first element contains a vector filled with crossings of cl with path_2geom
548 for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
549 if ((*m).ta >= 0 && (*m).ta <= 1 ) {
550 // Reconstruct the point of intersection
551 NR::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
552 // When it's within snapping range, then return it
553 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
554 NR::Coord dist = NR::L2(desktop->dt2doc(p_proj_on_cl) - p_inters);
555 SnappedPoint s(desktop->doc2dt(p_inters), SNAPTARGET_PATH, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
556 sc.points.push_back(s);
557 }
558 }
559 }
560 }
561 }
562 }
565 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
566 Inkscape::Snapper::PointType const &t,
567 NR::Point const &p,
568 bool const &first_point,
569 NR::Maybe<NR::Rect> const &bbox_to_snap,
570 std::vector<SPItem const *> const *it,
571 std::vector<NR::Point> *unselected_nodes) const
572 {
573 if (_snap_enabled == false || getSnapFrom(t) == false || _named_view == NULL) {
574 return;
575 }
577 /* Get a list of all the SPItems that we will try to snap to */
578 if (first_point) {
579 NR::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : NR::Rect(p, p);
580 _findCandidates(sp_document_root(_named_view->document), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY);
581 }
583 if (_snap_to_itemnode || _snap_to_bboxnode) {
584 _snapNodes(sc, t, p, first_point, unselected_nodes);
585 }
587 // Consider the page's border for snapping to
588 NArtBpath const *border_bpath = _snap_to_page_border ? _getBorderBPath() : NULL;
590 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
591 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
592 if (n > 0) {
593 /* While editing a path in the node tool, findCandidates must ignore that path because
594 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
595 * That path must not be ignored however when snapping to the paths, so we add it here
596 * manually when applicable
597 */
598 SPPath *path = NULL;
599 if (it != NULL) {
600 g_assert(SP_IS_PATH(*it->begin()));
601 g_assert(it->size() == 1);
602 path = SP_PATH(*it->begin());
603 }
604 _snapPaths(sc, t, p, first_point, unselected_nodes, path, border_bpath);
605 } else {
606 _snapPaths(sc, t, p, first_point, NULL, NULL, border_bpath);
607 }
608 }
609 }
611 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
612 Inkscape::Snapper::PointType const &t,
613 NR::Point const &p,
614 bool const &first_point,
615 NR::Maybe<NR::Rect> const &bbox_to_snap,
616 ConstraintLine const &c,
617 std::vector<SPItem const *> const *it) const
618 {
619 if (_snap_enabled == false || getSnapFrom(t) == false || _named_view == NULL) {
620 return;
621 }
623 /* Get a list of all the SPItems that we will try to snap to */
624 if (first_point) {
625 NR::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : NR::Rect(p, p);
626 _findCandidates(sp_document_root(_named_view->document), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY);
627 }
629 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
630 // This is usefull for example when scaling an object while maintaining a fixed aspect ratio. It's
631 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
633 // When snapping to objects, we either snap to their nodes or their paths. It is however very
634 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
635 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
636 // so we will more or less snap to them anyhow.
638 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
639 _snapPathsConstrained(sc, t, p, first_point, c);
640 }
641 }
644 // This method is used to snap a guide to nodes, while dragging the guide around
645 void Inkscape::ObjectSnapper::guideSnap(SnappedConstraints &sc,
646 NR::Point const &p,
647 NR::Point const &guide_normal) const
648 {
649 if ( NULL == _named_view ) {
650 return;
651 }
653 /* Get a list of all the SPItems that we will try to snap to */
654 std::vector<SPItem*> cand;
655 std::vector<SPItem const *> const it; //just an empty list
657 DimensionToSnap snap_dim;
658 if (guide_normal == component_vectors[NR::Y]) {
659 snap_dim = GUIDE_TRANSL_SNAP_Y;
660 } else if (guide_normal == component_vectors[NR::X]) {
661 snap_dim = GUIDE_TRANSL_SNAP_X;
662 } else {
663 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
664 }
666 // We don't support ANGLED_GUIDE_ROT_SNAP yet.
668 // It would be cool to allow the user to rotate a guide by dragging it, instead of
669 // only translating it. (For example when CTRL is pressed). We will need an UI part
670 // for that first; and some important usability choices need to be made:
671 // E.g. which point should be used for pivoting? A previously snapped point,
672 // or a transformation center (which can be moved after clicking for the
673 // second time on an object; but should this point then be constrained to the
674 // line, or can it be located anywhere?)
676 _findCandidates(sp_document_root(_named_view->document), &it, true, NR::Rect(p, p), snap_dim);
677 _snapTranslatingGuideToNodes(sc, Inkscape::Snapper::SNAPPOINT_GUIDE, p, guide_normal);
679 // _snapRotatingGuideToNodes has not been implemented yet.
680 }
682 /**
683 * \return true if this Snapper will snap at least one kind of point.
684 */
685 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
686 {
687 bool snap_to_something = _snap_to_itempath || _snap_to_itemnode || _snap_to_bboxpath || _snap_to_bboxnode || _snap_to_page_border;
688 return (_snap_enabled && _snap_from != 0 && snap_to_something);
689 }
691 bool Inkscape::ObjectSnapper::GuidesMightSnap() const
692 {
693 bool snap_to_something = _snap_to_itemnode || _snap_to_bboxnode;
694 return (_snap_enabled && (_snap_from & SNAPPOINT_GUIDE) && snap_to_something);
695 }
697 void Inkscape::ObjectSnapper::_clear_paths() const
698 {
699 for (std::vector<NArtBpath*>::const_iterator k = _bpaths_to_snap_to->begin(); k != _bpaths_to_snap_to->end(); k++) {
700 g_free(*k);
701 }
702 _bpaths_to_snap_to->clear();
704 for (std::vector<Path*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
705 delete *k;
706 }
707 _paths_to_snap_to->clear();
708 }
710 NArtBpath const* Inkscape::ObjectSnapper::_getBorderBPath() const
711 {
712 NArtBpath const *border_bpath = NULL;
713 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)));
714 SPCurve const *border_curve = SPCurve::new_from_rect(border_rect);
715 if (border_curve) {
716 border_bpath = SP_CURVE_BPATH(border_curve);
717 }
719 return border_bpath;
720 }
721 /*
722 Local Variables:
723 mode:c++
724 c-file-style:"stroustrup"
725 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
726 indent-tabs-mode:nil
727 fill-column:99
728 End:
729 */
730 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :