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 <2geom/point.h>
21 #include <2geom/rect.h>
22 #include "document.h"
23 #include "sp-namedview.h"
24 #include "sp-image.h"
25 #include "sp-item-group.h"
26 #include "sp-item.h"
27 #include "sp-use.h"
28 #include "display/curve.h"
29 #include "desktop.h"
30 #include "inkscape.h"
31 #include "prefs-utils.h"
32 #include "sp-text.h"
33 #include "sp-flowtext.h"
34 #include "text-editing.h"
36 Inkscape::ObjectSnapper::ObjectSnapper(SPNamedView const *nv, NR::Coord const d)
37 : Snapper(nv, d), _snap_to_itemnode(true), _snap_to_itempath(true),
38 _snap_to_bboxnode(true), _snap_to_bboxpath(true), _snap_to_page_border(false),
39 _strict_snapping(true), _include_item_center(false)
40 {
41 _candidates = new std::vector<SPItem*>;
42 _points_to_snap_to = new std::vector<NR::Point>;
43 _bpaths_to_snap_to = new std::vector<NArtBpath*>;
44 _paths_to_snap_to = new std::vector<Path*>;
45 }
47 Inkscape::ObjectSnapper::~ObjectSnapper()
48 {
49 _candidates->clear(); //Don't delete the candidates themselves, as these are not ours!
50 delete _candidates;
52 _points_to_snap_to->clear();
53 delete _points_to_snap_to;
55 _clear_paths();
56 delete _paths_to_snap_to;
57 delete _bpaths_to_snap_to;
58 }
60 /**
61 * Find all items within snapping range.
62 * \param r Pointer to the current document
63 * \param it List of items to ignore
64 * \param first_point If true then this point is the first one from a whole bunch of points
65 * \param bbox_to_snap Bounding box hulling the whole bunch of points, all from the same selection and having the same transformation
66 * \param DimensionToSnap Snap in X, Y, or both directions.
67 */
69 void Inkscape::ObjectSnapper::_findCandidates(SPObject* r,
70 std::vector<SPItem const *> const *it,
71 bool const &first_point,
72 NR::Rect const &bbox_to_snap,
73 DimensionToSnap const snap_dim) const
74 {
75 bool const c1 = (snap_dim == TRANSL_SNAP_XY) && ThisSnapperMightSnap();
76 bool const c2 = (snap_dim != TRANSL_SNAP_XY) && GuidesMightSnap();
78 if (!(c1 || c2)) {
79 return;
80 }
82 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
84 if (first_point) {
85 _candidates->clear();
86 }
88 NR::Maybe<NR::Rect> bbox_of_item = NR::Rect(); // a default NR::Rect is infinitely large
89 NR::Rect bbox_to_snap_incl = bbox_to_snap; // _incl means: will include the snapper tolerance
90 bbox_to_snap_incl.growBy(getSnapperTolerance()); // see?
92 for (SPObject* o = sp_object_first_child(r); o != NULL; o = SP_OBJECT_NEXT(o)) {
93 if (SP_IS_ITEM(o) && !SP_ITEM(o)->isLocked() && !desktop->itemIsHidden(SP_ITEM(o))) {
95 /* See if this item is on the ignore list */
96 std::vector<SPItem const *>::const_iterator i;
97 if (it != NULL) {
98 i = it->begin();
99 while (i != it->end() && *i != o) {
100 i++;
101 }
102 }
104 if (it == NULL || i == it->end()) {
105 /* See if the item is within range */
106 if (SP_IS_GROUP(o)) {
107 _findCandidates(o, it, false, bbox_to_snap, snap_dim);
108 } else {
109 bbox_of_item = sp_item_bbox_desktop(SP_ITEM(o));
110 if (bbox_of_item) {
111 if (bbox_to_snap_incl.intersects(*bbox_of_item)) {
112 //This item is within snapping range, so record it as a candidate
113 _candidates->push_back(SP_ITEM(o));
114 }
115 }
116 }
117 }
118 }
119 }
120 }
123 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::Snapper::PointType const &t,
124 bool const &first_point) const
125 {
126 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
127 // e.g. when translating an item using the selector tool, then we will only do this for the
128 // first point and store the collection for later use. This significantly improves the performance
129 if (first_point) {
130 _points_to_snap_to->clear();
132 // Determine the type of bounding box we should snap to
133 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
135 bool p_is_a_node = t & Inkscape::Snapper::SNAPPOINT_NODE;
136 bool p_is_a_bbox = t & Inkscape::Snapper::SNAPPOINT_BBOX;
137 bool p_is_a_guide = t & Inkscape::Snapper::SNAPPOINT_GUIDE;
139 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
140 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));
142 if (_snap_to_bboxnode) {
143 int prefs_bbox = prefs_get_int_attribute("tools", "bounding_box", 0);
144 bbox_type = (prefs_bbox ==0)?
145 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
146 }
148 for (std::vector<SPItem*>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
149 //NR::Matrix i2doc(NR::identity());
150 SPItem *root_item = *i;
151 if (SP_IS_USE(*i)) {
152 root_item = sp_use_root(SP_USE(*i));
153 }
154 g_return_if_fail(root_item);
156 //Collect all nodes so we can snap to them
157 if (_snap_to_itemnode) {
158 if (!(_strict_snapping && !p_is_a_node) || p_is_a_guide) {
159 sp_item_snappoints(root_item, _include_item_center, SnapPointsIter(*_points_to_snap_to));
160 }
161 }
163 //Collect the bounding box's corners so we can snap to them
164 if (_snap_to_bboxnode) {
165 if (!(_strict_snapping && !p_is_a_bbox) || p_is_a_guide) {
166 NR::Maybe<NR::Rect> b = sp_item_bbox_desktop(root_item, bbox_type);
167 if (b) {
168 for ( unsigned k = 0 ; k < 4 ; k++ ) {
169 _points_to_snap_to->push_back(b->corner(k));
170 }
171 }
172 }
173 }
174 }
175 }
176 }
178 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
179 Inkscape::Snapper::PointType const &t,
180 NR::Point const &p,
181 bool const &first_point,
182 std::vector<NR::Point> *unselected_nodes) const
183 {
184 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
186 _collectNodes(t, first_point);
188 if (unselected_nodes != NULL) {
189 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
190 }
192 SnappedPoint s;
193 bool success = false;
195 for (std::vector<NR::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
196 NR::Coord dist = NR::L2(*k - p);
197 if (dist < getSnapperTolerance() && dist < s.getDistance()) {
198 s = SnappedPoint(*k, SNAPTARGET_NODE, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
199 success = true;
200 }
201 }
203 if (success) {
204 sc.points.push_back(s);
205 }
206 }
208 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
209 Inkscape::Snapper::PointType const &t,
210 NR::Point const &p,
211 NR::Point const &guide_normal) const
212 {
213 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
214 _collectNodes(t, true);
216 SnappedPoint s;
217 bool success = false;
219 NR::Coord tol = getSnapperTolerance();
221 for (std::vector<NR::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
222 // Project each node (*k) on the guide line (running through point p)
223 NR::Point p_proj = project_on_linesegment(*k, p, p + NR::rot90(guide_normal));
224 NR::Coord dist = NR::L2(*k - p_proj); // distance from node to the guide
225 NR::Coord dist2 = NR::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
226 if ((dist < tol && dist2 < tol || getSnapperAlwaysSnap()) && dist < s.getDistance()) {
227 s = SnappedPoint(*k, SNAPTARGET_NODE, dist, tol, getSnapperAlwaysSnap());
228 success = true;
229 }
230 }
232 if (success) {
233 sc.points.push_back(s);
234 }
235 }
237 /**
238 * Returns index of first NR_END bpath in array.
239 */
240 static unsigned sp_bpath_length(NArtBpath const bpath[])
241 {
242 g_return_val_if_fail(bpath != NULL, FALSE);
243 unsigned ret = 0;
244 while ( bpath[ret].code != NR_END ) {
245 ++ret;
246 }
247 ++ret;
248 return ret;
249 }
251 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::Snapper::PointType const &t,
252 bool const &first_point,
253 NArtBpath const *border_bpath) const
254 {
255 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
256 // e.g. when translating an item using the selector tool, then we will only do this for the
257 // first point and store the collection for later use. This significantly improves the performance
258 if (first_point) {
259 _clear_paths();
261 // Determine the type of bounding box we should snap to
262 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
264 bool p_is_a_node = t & Inkscape::Snapper::SNAPPOINT_NODE;
266 if (_snap_to_bboxpath) {
267 int prefs_bbox = prefs_get_int_attribute("tools", "bounding_box", 0);
268 bbox_type = (prefs_bbox ==0)?
269 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
270 }
272 // Consider the page border for snapping
273 if (border_bpath != NULL) {
274 // make our own copy of the const*
275 NArtBpath *new_bpath;
276 unsigned const len = sp_bpath_length(border_bpath);
277 new_bpath = g_new(NArtBpath, len);
278 memcpy(new_bpath, border_bpath, len * sizeof(NArtBpath));
280 _bpaths_to_snap_to->push_back(new_bpath);
281 }
283 for (std::vector<SPItem*>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
285 /* Transform the requested snap point to this item's coordinates */
286 NR::Matrix i2doc(NR::identity());
287 SPItem *root_item = NULL;
288 /* We might have a clone at hand, so make sure we get the root item */
289 if (SP_IS_USE(*i)) {
290 i2doc = sp_use_get_root_transform(SP_USE(*i));
291 root_item = sp_use_root(SP_USE(*i));
292 g_return_if_fail(root_item);
293 } else {
294 i2doc = from_2geom(sp_item_i2doc_affine(*i));
295 root_item = *i;
296 }
298 //Build a list of all paths considered for snapping to
300 //Add the item's path to snap to
301 if (_snap_to_itempath) {
302 if (!(_strict_snapping && !p_is_a_node)) {
303 // Snapping to the path of characters is very cool, but for a large
304 // chunk of text this will take ages! So limit snapping to text paths
305 // containing max. 240 characters. Snapping the bbox will not be affected
306 bool very_lenghty_prose = false;
307 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
308 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
309 }
310 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
311 // which corresponds to a lag of 500 msec. This is for snapping a rect
312 // to a single line of text.
314 // Snapping for example to a traced bitmap is also very stressing for
315 // the CPU, so we'll only snap to paths having no more than 500 nodes
316 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
317 bool very_complex_path = false;
318 if (SP_IS_PATH(root_item)) {
319 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
320 }
322 if (!very_lenghty_prose && !very_complex_path) {
323 SPCurve *curve = curve_for_item(root_item);
324 if (curve) {
325 NArtBpath *bpath = bpath_for_curve(root_item, curve, true, true); // perhaps for speed, get a reference to the Geom::pathvector, and store the transformation besides it. apply transformation on the snap points, instead of generating whole new path
326 _bpaths_to_snap_to->push_back(bpath); // we 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); // we will get a dupe of the path, which must be freed at some point
380 curve->unref();
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 //pts describes a polyline approximation, which might consist of 1000s of points!
401 NR::Point start_point;
402 NR::Point end_point;
403 NR::Maybe<Path::cut_position> o = NR::Nothing();
404 if (being_edited) {
405 /* If the path is being edited, then we will try to snap to each piece of the
406 * path individually. We should only snap though to stationary pieces of the paths
407 * and not to the pieces that are being dragged around. This way we avoid
408 * self-snapping. For this we check whether the nodes at both ends of the current
409 * piece are unselected; if they are then this piece must be stationary
410 */
411 unsigned piece = (*k)->pts[i].piece;
412 // Example: a cubic spline is a single piece within a path; it will be drawn using
413 // a polyline, which is described by the collection of lines between the points pts[i]
414 (*k)->PointAt(piece, 0, start_point);
415 (*k)->PointAt(piece, 1, end_point);
416 start_point = desktop->doc2dt(start_point);
417 end_point = desktop->doc2dt(end_point);
418 g_assert(unselected_nodes != NULL);
419 bool c1 = isUnselectedNode(start_point, unselected_nodes);
420 bool c2 = isUnselectedNode(end_point, unselected_nodes);
421 if (c1 && c2) {
422 o = get_nearest_position_on_Path(*k, p_doc, i);
423 }
424 } else {
425 /* If the path is NOT being edited, then we will try to snap to the path as a
426 * whole, so we need to do this only once and we will break out at the end of
427 * this for-loop iteration */
428 /* Look for the nearest position on this SPItem to our snap point */
429 o = get_nearest_position_on_Path(*k, p_doc);
430 (*k)->PointAt(o->piece, 0, start_point);
431 (*k)->PointAt(o->piece, 1, end_point);
432 start_point = desktop->doc2dt(start_point);
433 end_point = desktop->doc2dt(end_point);
434 }
436 if (o && o->t >= 0 && o->t <= 1) {
437 /* Convert the nearest point back to desktop coordinates */
438 NR::Point const o_it = get_point_on_Path(*k, o->piece, o->t);
440 /* IF YOU'RE BUG HUNTING: IT LOOKS LIKE get_point_on_Path SOMETIMES
441 * RETURNS THE WRONG POINT (WITH AN OFFSET, BUT STILL ON THE PATH.
442 * THIS BUG WILL NO LONGER BE ENCOUNTERED ONCE WE'VE SWITCHED TO
443 * 2GEOM FOR THE OBJECT SNAPPER
444 */
446 NR::Point const o_dt = desktop->doc2dt(o_it);
447 NR::Coord const dist = NR::L2(o_dt - p);
449 if (dist < getSnapperTolerance()) {
450 // if we snap to a straight line segment (within a path), then return this line segment
451 if ((*k)->IsLineSegment(o->piece)) {
452 sc.lines.push_back(Inkscape::SnappedLineSegment(o_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), start_point, end_point));
453 } else {
454 // for segments other than straight lines of a path, we'll return just the closest snapped point
455 if (dist < s.getDistance()) {
456 s = SnappedPoint(o_dt, SNAPTARGET_PATH, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
457 success = true;
458 }
459 }
460 }
461 }
463 // If the path is NOT being edited, then we will try to snap to the path as a whole
464 // so we need to do this only once
465 if (!being_edited) break;
466 }
467 }
468 }
470 if (success) {
471 sc.points.push_back(s);
472 }
473 }
475 /* Returns true if point is coincident with one of the unselected nodes */
476 bool Inkscape::ObjectSnapper::isUnselectedNode(NR::Point const &point, std::vector<NR::Point> const *unselected_nodes) const
477 {
478 if (unselected_nodes == NULL) {
479 return false;
480 }
482 if (unselected_nodes->size() == 0) {
483 return false;
484 }
486 for (std::vector<NR::Point>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
487 if (NR::L2(point - *i) < 1e-4) {
488 return true;
489 }
490 }
492 return false;
493 }
495 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
496 Inkscape::Snapper::PointType const &t,
497 NR::Point const &p,
498 bool const &first_point,
499 ConstraintLine const &c) const
500 {
502 // Consider the page's border for snapping to
503 NArtBpath const *border_bpath = _snap_to_page_border ? _getBorderBPath() : NULL;
505 _collectPaths(t, first_point, border_bpath);
507 // Now we can finally do the real snapping, using the paths collected above
509 /* FIXME: this seems like a hack. Perhaps Snappers should be
510 ** in SPDesktop rather than SPNamedView?
511 */
512 SPDesktop const *desktop = SP_ACTIVE_DESKTOP;
513 NR::Point const p_doc = desktop->dt2doc(p);
515 NR::Point direction_vector = c.getDirection();
516 if (!is_zero(direction_vector)) {
517 direction_vector = NR::unit_vector(direction_vector);
518 }
520 NR::Point const p1_on_cl = c.hasPoint() ? c.getPoint() : p;
521 NR::Point const p2_on_cl = p1_on_cl + direction_vector;
523 // The intersection point of the constraint line with any path,
524 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
525 // The distance between those points is twice the snapping tolerance
526 NR::Point const p_proj_on_cl = project_on_linesegment(p, p1_on_cl, p2_on_cl);
527 NR::Point const p_min_on_cl = desktop->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
528 NR::Point const p_max_on_cl = desktop->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
530 Geom::Path cl;
531 std::vector<Geom::Path> clv;
532 cl.start(p_min_on_cl.to_2geom());
533 cl.appendNew<Geom::LineSegment>(p_max_on_cl.to_2geom());
534 clv.push_back(cl);
536 for (std::vector<NArtBpath*>::const_iterator k = _bpaths_to_snap_to->begin(); k != _bpaths_to_snap_to->end(); k++) {
537 if (*k) {
538 // convert a Path object (see src/livarot/Path.h) to a 2geom's path object (see 2geom/path.h)
539 // TODO: (Diederik) Only do this once for the first point, needs some storage of pointers in a member variable
540 std::vector<Geom::Path> path_2geom = BPath_to_2GeomPath(*k);
542 Geom::CrossingSet cs = Geom::crossings(clv, path_2geom);
543 if (cs.size() > 0) {
544 // We need only the first element of cs, because cl is only a single straight linesegment
545 // This first element contains a vector filled with crossings of cl with path_2geom
546 for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
547 if ((*m).ta >= 0 && (*m).ta <= 1 ) {
548 // Reconstruct the point of intersection
549 NR::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
550 // When it's within snapping range, then return it
551 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
552 NR::Coord dist = NR::L2(desktop->dt2doc(p_proj_on_cl) - p_inters);
553 SnappedPoint s(desktop->doc2dt(p_inters), SNAPTARGET_PATH, dist, getSnapperTolerance(), getSnapperAlwaysSnap());
554 sc.points.push_back(s);
555 }
556 }
557 }
558 }
559 }
560 }
563 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
564 Inkscape::Snapper::PointType const &t,
565 NR::Point const &p,
566 bool const &first_point,
567 NR::Maybe<NR::Rect> const &bbox_to_snap,
568 std::vector<SPItem const *> const *it,
569 std::vector<NR::Point> *unselected_nodes) const
570 {
571 if (_snap_enabled == false || getSnapFrom(t) == false || _named_view == NULL) {
572 return;
573 }
575 /* Get a list of all the SPItems that we will try to snap to */
576 if (first_point) {
577 NR::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : NR::Rect(p, p);
578 _findCandidates(sp_document_root(_named_view->document), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY);
579 }
581 if (_snap_to_itemnode || _snap_to_bboxnode) {
582 _snapNodes(sc, t, p, first_point, unselected_nodes);
583 }
585 // Consider the page's border for snapping to
586 NArtBpath const *border_bpath = _snap_to_page_border ? _getBorderBPath() : NULL;
588 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
589 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
590 if (n > 0) {
591 /* While editing a path in the node tool, findCandidates must ignore that path because
592 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
593 * That path must not be ignored however when snapping to the paths, so we add it here
594 * manually when applicable
595 */
596 SPPath *path = NULL;
597 if (it != NULL) {
598 g_assert(SP_IS_PATH(*it->begin()));
599 g_assert(it->size() == 1);
600 path = SP_PATH(*it->begin());
601 }
602 _snapPaths(sc, t, p, first_point, unselected_nodes, path, border_bpath);
603 } else {
604 _snapPaths(sc, t, p, first_point, NULL, NULL, border_bpath);
605 }
606 }
607 }
609 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
610 Inkscape::Snapper::PointType const &t,
611 NR::Point const &p,
612 bool const &first_point,
613 NR::Maybe<NR::Rect> const &bbox_to_snap,
614 ConstraintLine const &c,
615 std::vector<SPItem const *> const *it) const
616 {
617 if (_snap_enabled == false || getSnapFrom(t) == false || _named_view == NULL) {
618 return;
619 }
621 /* Get a list of all the SPItems that we will try to snap to */
622 if (first_point) {
623 NR::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : NR::Rect(p, p);
624 _findCandidates(sp_document_root(_named_view->document), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY);
625 }
627 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
628 // This is usefull for example when scaling an object while maintaining a fixed aspect ratio. It's
629 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
631 // When snapping to objects, we either snap to their nodes or their paths. It is however very
632 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
633 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
634 // so we will more or less snap to them anyhow.
636 if (_snap_to_itempath || _snap_to_bboxpath || _snap_to_page_border) {
637 _snapPathsConstrained(sc, t, p, first_point, c);
638 }
639 }
642 // This method is used to snap a guide to nodes, while dragging the guide around
643 void Inkscape::ObjectSnapper::guideSnap(SnappedConstraints &sc,
644 NR::Point const &p,
645 NR::Point const &guide_normal) const
646 {
647 if ( NULL == _named_view ) {
648 return;
649 }
651 /* Get a list of all the SPItems that we will try to snap to */
652 std::vector<SPItem*> cand;
653 std::vector<SPItem const *> const it; //just an empty list
655 DimensionToSnap snap_dim;
656 if (guide_normal == component_vectors[NR::Y]) {
657 snap_dim = GUIDE_TRANSL_SNAP_Y;
658 } else if (guide_normal == component_vectors[NR::X]) {
659 snap_dim = GUIDE_TRANSL_SNAP_X;
660 } else {
661 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
662 }
664 // We don't support ANGLED_GUIDE_ROT_SNAP yet.
666 // It would be cool to allow the user to rotate a guide by dragging it, instead of
667 // only translating it. (For example when CTRL is pressed). We will need an UI part
668 // for that first; and some important usability choices need to be made:
669 // E.g. which point should be used for pivoting? A previously snapped point,
670 // or a transformation center (which can be moved after clicking for the
671 // second time on an object; but should this point then be constrained to the
672 // line, or can it be located anywhere?)
674 _findCandidates(sp_document_root(_named_view->document), &it, true, NR::Rect(p, p), snap_dim);
675 _snapTranslatingGuideToNodes(sc, Inkscape::Snapper::SNAPPOINT_GUIDE, p, guide_normal);
677 // _snapRotatingGuideToNodes has not been implemented yet.
678 }
680 /**
681 * \return true if this Snapper will snap at least one kind of point.
682 */
683 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
684 {
685 bool snap_to_something = _snap_to_itempath || _snap_to_itemnode || _snap_to_bboxpath || _snap_to_bboxnode || _snap_to_page_border;
686 return (_snap_enabled && _snap_from != 0 && snap_to_something);
687 }
689 bool Inkscape::ObjectSnapper::GuidesMightSnap() const
690 {
691 bool snap_to_something = _snap_to_itemnode || _snap_to_bboxnode;
692 return (_snap_enabled && (_snap_from & SNAPPOINT_GUIDE) && snap_to_something);
693 }
695 void Inkscape::ObjectSnapper::_clear_paths() const
696 {
697 for (std::vector<NArtBpath*>::const_iterator k = _bpaths_to_snap_to->begin(); k != _bpaths_to_snap_to->end(); k++) {
698 g_free(*k);
699 }
700 _bpaths_to_snap_to->clear();
702 for (std::vector<Path*>::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
703 delete *k;
704 }
705 _paths_to_snap_to->clear();
706 }
708 NArtBpath const* Inkscape::ObjectSnapper::_getBorderBPath() const
709 {
710 NArtBpath const *border_bpath = NULL;
711 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)));
712 SPCurve const *border_curve = SPCurve::new_from_rect(border_rect);
713 if (border_curve) {
714 border_bpath = SP_CURVE_BPATH(border_curve);
715 }
717 return border_bpath;
718 }
719 /*
720 Local Variables:
721 mode:c++
722 c-file-style:"stroustrup"
723 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
724 indent-tabs-mode:nil
725 fill-column:99
726 End:
727 */
728 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :