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 - 2010 Authors
10 *
11 * Released under GNU GPL, read the file 'COPYING' for more information
12 */
14 #include "svg/svg.h"
15 #include <2geom/path-intersection.h>
16 #include <2geom/pathvector.h>
17 #include <2geom/point.h>
18 #include <2geom/rect.h>
19 #include <2geom/line.h>
20 #include <2geom/circle.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 "inkscape.h"
29 #include "preferences.h"
30 #include "sp-text.h"
31 #include "sp-flowtext.h"
32 #include "text-editing.h"
33 #include "sp-clippath.h"
34 #include "sp-mask.h"
35 #include "helper/geom-curves.h"
36 #include "desktop.h"
38 Inkscape::ObjectSnapper::ObjectSnapper(SnapManager *sm, Geom::Coord const d)
39 : Snapper(sm, d)
40 {
41 _candidates = new std::vector<SnapCandidateItem>;
42 _points_to_snap_to = new std::vector<Inkscape::SnapCandidatePoint>;
43 _paths_to_snap_to = new std::vector<Inkscape::SnapCandidatePath >;
44 }
46 Inkscape::ObjectSnapper::~ObjectSnapper()
47 {
48 _candidates->clear();
49 delete _candidates;
51 _points_to_snap_to->clear();
52 delete _points_to_snap_to;
54 _clear_paths();
55 delete _paths_to_snap_to;
56 }
58 /**
59 * \return Snap tolerance (desktop coordinates); depends on current zoom so that it's always the same in screen pixels
60 */
61 Geom::Coord Inkscape::ObjectSnapper::getSnapperTolerance() const
62 {
63 SPDesktop const *dt = _snapmanager->getDesktop();
64 double const zoom = dt ? dt->current_zoom() : 1;
65 return _snapmanager->snapprefs.getObjectTolerance() / zoom;
66 }
68 bool Inkscape::ObjectSnapper::getSnapperAlwaysSnap() const
69 {
70 return _snapmanager->snapprefs.getObjectTolerance() == 10000; //TODO: Replace this threshold of 10000 by a constant; see also tolerance-slider.cpp
71 }
73 /**
74 * Find all items within snapping range.
75 * \param parent Pointer to the document's root, or to a clipped path or mask object
76 * \param it List of items to ignore
77 * \param bbox_to_snap Bounding box hulling the whole bunch of points, all from the same selection and having the same transformation
78 */
80 void Inkscape::ObjectSnapper::_findCandidates(SPObject* parent,
81 std::vector<SPItem const *> const *it,
82 bool const &first_point,
83 Geom::Rect const &bbox_to_snap,
84 bool const clip_or_mask,
85 Geom::Matrix const additional_affine) const // transformation of the item being clipped / masked
86 {
87 if (!ThisSnapperMightSnap()) {
88 return;
89 }
91 if (_snapmanager->getDesktop() == NULL) {
92 g_warning("desktop == NULL, so we cannot snap; please inform the developpers of this bug");
93 // Apparently the etup() method from the SnapManager class hasn't been called before trying to snap.
94 }
96 if (first_point) {
97 _candidates->clear();
98 }
100 Geom::Rect bbox_to_snap_incl = bbox_to_snap; // _incl means: will include the snapper tolerance
101 bbox_to_snap_incl.expandBy(getSnapperTolerance()); // see?
103 for (SPObject* o = sp_object_first_child(parent); o != NULL; o = SP_OBJECT_NEXT(o)) {
104 if (SP_IS_ITEM(o) && !(_snapmanager->getDesktop()->itemIsHidden(SP_ITEM(o)) && !clip_or_mask)) {
105 // Snapping to items in a locked layer is allowed
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 if (item) {
119 SPObject *obj = NULL;
120 if (!clip_or_mask) { // cannot clip or mask more than once
121 // The current item is not a clipping path or a mask, but might
122 // still be the subject of clipping or masking itself ; if so, then
123 // we should also consider that path or mask for snapping to
124 obj = SP_OBJECT(item->clip_ref->getObject());
125 if (obj) {
126 _findCandidates(obj, it, false, bbox_to_snap, true, sp_item_i2doc_affine(item));
127 }
128 obj = SP_OBJECT(item->mask_ref->getObject());
129 if (obj) {
130 _findCandidates(obj, it, false, bbox_to_snap, true, sp_item_i2doc_affine(item));
131 }
132 }
133 }
135 if (SP_IS_GROUP(o)) {
136 _findCandidates(o, it, false, bbox_to_snap, clip_or_mask, additional_affine);
137 } else {
138 Geom::OptRect bbox_of_item = Geom::Rect();
139 if (clip_or_mask) {
140 // Oh oh, this will get ugly. We cannot use sp_item_i2d_affine directly because we need to
141 // insert an additional transformation in document coordinates (code copied from sp_item_i2d_affine)
142 sp_item_invoke_bbox(item,
143 bbox_of_item,
144 sp_item_i2doc_affine(item) * additional_affine * _snapmanager->getDesktop()->doc2dt(),
145 true);
146 } else {
147 sp_item_invoke_bbox(item, bbox_of_item, sp_item_i2d_affine(item), true);
148 }
149 if (bbox_of_item) {
150 // See if the item is within range
151 if (bbox_to_snap_incl.intersects(*bbox_of_item)
152 || (_snapmanager->snapprefs.getIncludeItemCenter() && bbox_to_snap_incl.contains(item->getCenter()))) { // rotation center might be outside of the bounding box
153 // This item is within snapping range, so record it as a candidate
154 _candidates->push_back(SnapCandidateItem(item, clip_or_mask, additional_affine));
155 // For debugging: print the id of the candidate to the console
156 // SPObject *obj = (SPObject*)item;
157 // std::cout << "Snap candidate added: " << obj->getId() << std::endl;
158 }
159 }
160 }
161 }
162 }
163 }
164 }
167 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::SnapSourceType const &t,
168 bool const &first_point) const
169 {
170 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
171 // e.g. when translating an item using the selector tool, then we will only do this for the
172 // first point and store the collection for later use. This significantly improves the performance
173 if (first_point) {
174 _points_to_snap_to->clear();
176 // Determine the type of bounding box we should snap to
177 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
179 bool p_is_a_node = t & Inkscape::SNAPSOURCE_NODE_CATEGORY;
180 bool p_is_a_bbox = t & Inkscape::SNAPSOURCE_BBOX_CATEGORY;
181 bool p_is_other = t & Inkscape::SNAPSOURCE_OTHER_CATEGORY;
183 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
184 g_assert(!((p_is_a_node && p_is_a_bbox) || (p_is_a_bbox && p_is_other) || (p_is_a_node && p_is_other)));
186 if (_snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()) {
187 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
188 bool prefs_bbox = prefs->getBool("/tools/bounding_box");
189 bbox_type = !prefs_bbox ?
190 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
191 }
193 // Consider the page border for snapping to
194 if (_snapmanager->snapprefs.getSnapToPageBorder()) {
195 _getBorderNodes(_points_to_snap_to);
196 }
198 for (std::vector<SnapCandidateItem>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
199 //Geom::Matrix i2doc(Geom::identity());
200 SPItem *root_item = (*i).item;
201 if (SP_IS_USE((*i).item)) {
202 root_item = sp_use_root(SP_USE((*i).item));
203 }
204 g_return_if_fail(root_item);
206 //Collect all nodes so we can snap to them
207 if (p_is_a_node || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node) || p_is_other) {
208 // Note: there are two ways in which intersections are considered:
209 // Method 1: Intersections are calculated for each shape individually, for both the
210 // snap source and snap target (see sp_shape_snappoints)
211 // Method 2: Intersections are calculated for each curve or line that we've snapped to, i.e. only for
212 // the target (see the intersect() method in the SnappedCurve and SnappedLine classes)
213 // Some differences:
214 // - Method 1 doesn't find intersections within a set of multiple objects
215 // - Method 2 only works for targets
216 // When considering intersections as snap targets:
217 // - Method 1 only works when snapping to nodes, whereas
218 // - Method 2 only works when snapping to paths
219 // - There will be performance differences too!
220 // If both methods are being used simultaneously, then this might lead to duplicate targets!
222 // Well, here we will be looking for snap TARGETS. Both methods can therefore be used.
223 // When snapping to paths, we will get a collection of snapped lines and snapped curves. findBestSnap() will
224 // go hunting for intersections (but only when asked to in the prefs of course). In that case we can just
225 // temporarily block the intersections in sp_item_snappoints, we don't need duplicates. If we're not snapping to
226 // paths though but only to item nodes then we should still look for the intersections in sp_item_snappoints()
227 bool old_pref = _snapmanager->snapprefs.getSnapIntersectionCS();
228 if (_snapmanager->snapprefs.getSnapToItemPath()) {
229 _snapmanager->snapprefs.setSnapIntersectionCS(false);
230 }
232 // We should not snap a transformation center to any of the centers of the items in the
233 // current selection (see the comment in SelTrans::centerRequest())
234 bool old_pref2 = _snapmanager->snapprefs.getIncludeItemCenter();
235 if (old_pref2) {
236 for ( GSList const *itemlist = _snapmanager->getRotationCenterSource(); itemlist != NULL; itemlist = g_slist_next(itemlist) ) {
237 if ((*i).item == reinterpret_cast<SPItem*>(itemlist->data)) {
238 // don't snap to this item's rotation center
239 _snapmanager->snapprefs.setIncludeItemCenter(false);
240 break;
241 }
242 }
243 }
245 sp_item_snappoints(root_item, *_points_to_snap_to, &_snapmanager->snapprefs);
247 // restore the original snap preferences
248 _snapmanager->snapprefs.setSnapIntersectionCS(old_pref);
249 _snapmanager->snapprefs.setIncludeItemCenter(old_pref2);
250 }
252 //Collect the bounding box's corners so we can snap to them
253 if (p_is_a_bbox || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_bbox) || p_is_other) {
254 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
255 // of the item AND the bbox of the clipping path at the same time
256 if (!(*i).clip_or_mask) {
257 Geom::OptRect b = sp_item_bbox_desktop(root_item, bbox_type);
258 getBBoxPoints(b, _points_to_snap_to, true, _snapmanager->snapprefs.getSnapToBBoxNode(), _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints(), _snapmanager->snapprefs.getSnapBBoxMidpoints());
259 }
260 }
261 }
262 }
263 }
265 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
266 Inkscape::SnapCandidatePoint const &p,
267 std::vector<SnapCandidatePoint> *unselected_nodes,
268 SnapConstraint const &c,
269 Geom::Point const &p_proj_on_constraint) const
270 {
271 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
273 _collectNodes(p.getSourceType(), p.getSourceNum() <= 0);
275 if (unselected_nodes != NULL && unselected_nodes->size() > 0) {
276 g_assert(_points_to_snap_to != NULL);
277 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
278 }
280 SnappedPoint s;
281 bool success = false;
283 for (std::vector<SnapCandidatePoint>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
284 Geom::Point target_pt = (*k).getPoint();
285 Geom::Coord dist = NR_HUGE;
286 if (!c.isUndefined()) {
287 // We're snapping to nodes along a constraint only, so find out if this node
288 // is at the constraint, while allowing for a small margin
289 if (Geom::L2(target_pt - c.projection(target_pt)) > 1e-9) {
290 // The distance from the target point to its projection on the constraint
291 // is too large, so this point is not on the constraint. Skip it!
292 continue;
293 }
294 dist = Geom::L2(target_pt - p_proj_on_constraint);
295 } else {
296 // Free (unconstrained) snapping
297 dist = Geom::L2(target_pt - p.getPoint());
298 }
300 if (dist < getSnapperTolerance() && dist < s.getSnapDistance()) {
301 s = SnappedPoint(target_pt, p.getSourceType(), p.getSourceNum(), (*k).getTargetType(), dist, getSnapperTolerance(), getSnapperAlwaysSnap(), false, true, (*k).getTargetBBox());
302 success = true;
303 }
304 }
306 if (success) {
307 sc.points.push_back(s);
308 }
309 }
311 void Inkscape::ObjectSnapper::_snapTranslatingGuide(SnappedConstraints &sc,
312 Geom::Point const &p,
313 Geom::Point const &guide_normal) const
314 {
315 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
316 _collectNodes(SNAPSOURCE_GUIDE, true);
318 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
319 _collectPaths(p, SNAPSOURCE_GUIDE, true);
320 _snapPaths(sc, Inkscape::SnapCandidatePoint(p, SNAPSOURCE_GUIDE), NULL, NULL);
321 }
323 SnappedPoint s;
325 Geom::Coord tol = getSnapperTolerance();
327 for (std::vector<SnapCandidatePoint>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
328 Geom::Point target_pt = (*k).getPoint();
329 // Project each node (*k) on the guide line (running through point p)
330 Geom::Point p_proj = Geom::projection(target_pt, Geom::Line(p, p + Geom::rot90(guide_normal)));
331 Geom::Coord dist = Geom::L2(target_pt - p_proj); // distance from node to the guide
332 Geom::Coord dist2 = Geom::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
333 if ((dist < tol && dist2 < tol) || getSnapperAlwaysSnap()) {
334 s = SnappedPoint(target_pt, SNAPSOURCE_GUIDE, 0, (*k).getTargetType(), dist, tol, getSnapperAlwaysSnap(), false, true, (*k).getTargetBBox());
335 sc.points.push_back(s);
336 }
337 }
338 }
341 /**
342 * Returns index of first NR_END bpath in array.
343 */
345 void Inkscape::ObjectSnapper::_collectPaths(Geom::Point p,
346 Inkscape::SnapSourceType const source_type,
347 bool const &first_point) const
348 {
349 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
350 // e.g. when translating an item using the selector tool, then we will only do this for the
351 // first point and store the collection for later use. This significantly improves the performance
352 if (first_point) {
353 _clear_paths();
355 // Determine the type of bounding box we should snap to
356 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
358 bool p_is_a_node = source_type & Inkscape::SNAPSOURCE_NODE_CATEGORY;
359 bool p_is_other = source_type & Inkscape::SNAPSOURCE_OTHER_CATEGORY;
361 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
362 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
363 int prefs_bbox = prefs->getBool("/tools/bounding_box", 0);
364 bbox_type = !prefs_bbox ?
365 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
366 }
368 // Consider the page border for snapping
369 if (_snapmanager->snapprefs.getSnapToPageBorder() && _snapmanager->snapprefs.getSnapModeBBoxOrNodes()) {
370 Geom::PathVector *border_path = _getBorderPathv();
371 if (border_path != NULL) {
372 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(border_path, SNAPTARGET_PAGE_BORDER, Geom::OptRect()));
373 }
374 }
376 for (std::vector<SnapCandidateItem>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
378 /* Transform the requested snap point to this item's coordinates */
379 Geom::Matrix i2doc(Geom::identity());
380 SPItem *root_item = NULL;
381 /* We might have a clone at hand, so make sure we get the root item */
382 if (SP_IS_USE((*i).item)) {
383 i2doc = sp_use_get_root_transform(SP_USE((*i).item));
384 root_item = sp_use_root(SP_USE((*i).item));
385 g_return_if_fail(root_item);
386 } else {
387 i2doc = sp_item_i2doc_affine((*i).item);
388 root_item = (*i).item;
389 }
391 //Build a list of all paths considered for snapping to
393 //Add the item's path to snap to
394 if (_snapmanager->snapprefs.getSnapToItemPath() && _snapmanager->snapprefs.getSnapModeNode()) {
395 if (p_is_other || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node)) {
396 // Snapping to the path of characters is very cool, but for a large
397 // chunk of text this will take ages! So limit snapping to text paths
398 // containing max. 240 characters. Snapping the bbox will not be affected
399 bool very_lenghty_prose = false;
400 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
401 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
402 }
403 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
404 // which corresponds to a lag of 500 msec. This is for snapping a rect
405 // to a single line of text.
407 // Snapping for example to a traced bitmap is also very stressing for
408 // the CPU, so we'll only snap to paths having no more than 500 nodes
409 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
410 bool very_complex_path = false;
411 if (SP_IS_PATH(root_item)) {
412 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
413 }
415 if (!very_lenghty_prose && !very_complex_path) {
416 SPCurve *curve = curve_for_item(root_item);
417 if (curve) {
418 // We will get our own copy of the pathvector, which must be freed at some point
420 // Geom::PathVector *pv = pathvector_for_curve(root_item, curve, true, true, Geom::identity(), (*i).additional_affine);
422 Geom::PathVector *pv = new Geom::PathVector(curve->get_pathvector());
423 (*pv) *= sp_item_i2d_affine(root_item) * (*i).additional_affine * _snapmanager->getDesktop()->doc2dt(); // (_edit_transform * _i2d_transform);
425 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(pv, SNAPTARGET_PATH, Geom::OptRect())); // Perhaps for speed, get a reference to the Geom::pathvector, and store the transformation besides it.
426 curve->unref();
427 }
428 }
429 }
430 }
432 //Add the item's bounding box to snap to
433 if (_snapmanager->snapprefs.getSnapToBBoxPath() && _snapmanager->snapprefs.getSnapModeBBox()) {
434 if (p_is_other || !(_snapmanager->snapprefs.getStrictSnapping() && p_is_a_node)) {
435 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
436 // of the item AND the bbox of the clipping path at the same time
437 if (!(*i).clip_or_mask) {
438 Geom::OptRect rect;
439 sp_item_invoke_bbox(root_item, rect, i2doc, TRUE, bbox_type);
440 if (rect) {
441 Geom::PathVector *path = _getPathvFromRect(*rect);
442 rect = sp_item_bbox_desktop(root_item, bbox_type);
443 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(path, SNAPTARGET_BBOX_EDGE, rect));
444 }
445 }
446 }
447 }
448 }
449 }
450 }
452 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
453 Inkscape::SnapCandidatePoint const &p,
454 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
455 SPPath const *selected_path) const
456 {
457 _collectPaths(p.getPoint(), p.getSourceType(), p.getSourceNum() <= 0);
458 // Now we can finally do the real snapping, using the paths collected above
460 g_assert(_snapmanager->getDesktop() != NULL);
461 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p.getPoint());
463 bool const node_tool_active = _snapmanager->snapprefs.getSnapToItemPath() && selected_path != NULL;
465 if (p.getSourceNum() <= 0) {
466 /* findCandidates() is used for snapping to both paths and nodes. It ignores the path that is
467 * currently being edited, because that path requires special care: when snapping to nodes
468 * only the unselected nodes of that path should be considered, and these will be passed on separately.
469 * This path must not be ignored however when snapping to the paths, so we add it here
470 * manually when applicable.
471 * */
472 if (node_tool_active) {
473 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
474 if (curve) {
475 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
476 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(pathv, SNAPTARGET_PATH, Geom::OptRect(), true));
477 curve->unref();
478 }
479 }
480 }
482 int num_path = 0;
483 int num_segm = 0;
485 for (std::vector<Inkscape::SnapCandidatePath >::const_iterator it_p = _paths_to_snap_to->begin(); it_p != _paths_to_snap_to->end(); it_p++) {
486 bool const being_edited = node_tool_active && (*it_p).currently_being_edited;
487 //if true then this pathvector it_pv is currently being edited in the node tool
489 for(Geom::PathVector::iterator it_pv = (it_p->path_vector)->begin(); it_pv != (it_p->path_vector)->end(); ++it_pv) {
490 // Find a nearest point for each curve within this path
491 // n curves will return n time values with 0 <= t <= 1
492 std::vector<double> anp = (*it_pv).nearestPointPerCurve(p_doc);
494 std::vector<double>::const_iterator np = anp.begin();
495 unsigned int index = 0;
496 for (; np != anp.end(); np++, index++) {
497 Geom::Curve const *curve = &((*it_pv).at_index(index));
498 Geom::Point const sp_doc = curve->pointAt(*np);
500 bool c1 = true;
501 bool c2 = true;
502 if (being_edited) {
503 /* If the path is being edited, then we should only snap though to stationary pieces of the path
504 * and not to the pieces that are being dragged around. This way we avoid
505 * self-snapping. For this we check whether the nodes at both ends of the current
506 * piece are unselected; if they are then this piece must be stationary
507 */
508 g_assert(unselected_nodes != NULL);
509 Geom::Point start_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(0));
510 Geom::Point end_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(1));
511 c1 = isUnselectedNode(start_pt, unselected_nodes);
512 c2 = isUnselectedNode(end_pt, unselected_nodes);
513 /* Unfortunately, this might yield false positives for coincident nodes. Inkscape might therefore mistakenly
514 * snap to path segments that are not stationary. There are at least two possible ways to overcome this:
515 * - Linking the individual nodes of the SPPath we have here, to the nodes of the NodePath::SubPath class as being
516 * used in sp_nodepath_selected_nodes_move. This class has a member variable called "selected". For this the nodes
517 * should be in the exact same order for both classes, so we can index them
518 * - Replacing the SPPath being used here by the the NodePath::SubPath class; but how?
519 */
520 }
522 Geom::Point const sp_dt = _snapmanager->getDesktop()->doc2dt(sp_doc);
523 if (!being_edited || (c1 && c2)) {
524 Geom::Coord const dist = Geom::distance(sp_doc, p_doc);
525 if (dist < getSnapperTolerance()) {
526 sc.curves.push_back(Inkscape::SnappedCurve(sp_dt, num_path, num_segm, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), false, curve, p.getSourceType(), p.getSourceNum(), it_p->target_type, it_p->target_bbox));
527 }
528 }
529 }
530 num_segm++;
531 } // End of: for (Geom::PathVector::iterator ....)
532 num_path++;
533 }
534 }
536 /* Returns true if point is coincident with one of the unselected nodes */
537 bool Inkscape::ObjectSnapper::isUnselectedNode(Geom::Point const &point, std::vector<Inkscape::SnapCandidatePoint> const *unselected_nodes) const
538 {
539 if (unselected_nodes == NULL) {
540 return false;
541 }
543 if (unselected_nodes->size() == 0) {
544 return false;
545 }
547 for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
548 if (Geom::L2(point - (*i).getPoint()) < 1e-4) {
549 return true;
550 }
551 }
553 return false;
554 }
556 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
557 Inkscape::SnapCandidatePoint const &p,
558 SnapConstraint const &c,
559 Geom::Point const &p_proj_on_constraint) const
560 {
562 _collectPaths(p_proj_on_constraint, p.getSourceType(), p.getSourceNum() <= 0);
564 // Now we can finally do the real snapping, using the paths collected above
566 g_assert(_snapmanager->getDesktop() != NULL);
567 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p_proj_on_constraint);
569 Geom::Point direction_vector = c.getDirection();
570 if (!is_zero(direction_vector)) {
571 direction_vector = Geom::unit_vector(direction_vector);
572 }
574 // The intersection point of the constraint line with any path, must lie within two points on the
575 // SnapConstraint: p_min_on_cl and p_max_on_cl. The distance between those points is twice the snapping tolerance
576 Geom::Point const p_min_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_constraint - getSnapperTolerance() * direction_vector);
577 Geom::Point const p_max_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_constraint + getSnapperTolerance() * direction_vector);
578 Geom::Coord tolerance = getSnapperTolerance();
580 // PS: Because the paths we're about to snap to are all expressed relative to document coordinate system, we will have
581 // to convert the snapper coordinates from the desktop coordinates to document coordinates
583 std::vector<Geom::Path> constraint_path;
584 if (c.isCircular()) {
585 Geom::Circle constraint_circle(_snapmanager->getDesktop()->dt2doc(c.getPoint()), c.getRadius());
586 constraint_circle.getPath(constraint_path);
587 } else {
588 Geom::Path constraint_line;
589 constraint_line.start(p_min_on_cl);
590 constraint_line.appendNew<Geom::LineSegment>(p_max_on_cl);
591 constraint_path.push_back(constraint_line);
592 }
593 // Length of constraint_path will always be one
595 // Find all intersections of the constrained path with the snap target candidates
596 std::vector<Geom::Point> intersections;
597 for (std::vector<Inkscape::SnapCandidatePath >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
598 if (k->path_vector) {
599 // Do the intersection math
600 Geom::CrossingSet cs = Geom::crossings(constraint_path, *(k->path_vector));
601 // Store the results as intersection points
602 unsigned int index = 0;
603 for (Geom::CrossingSet::const_iterator i = cs.begin(); i != cs.end(); i++) {
604 if (index >= constraint_path.size()) {
605 break;
606 }
607 // Reconstruct and store the points of intersection
608 for (Geom::Crossings::const_iterator m = (*i).begin(); m != (*i).end(); m++) {
609 intersections.push_back(constraint_path[index].pointAt((*m).ta));
610 }
611 index++;
612 }
614 //Geom::crossings will not consider the closing segment apparently, so we'll handle that separately here
615 //TODO: This should have been fixed in rev. #9859, which makes this workaround obsolete
616 for(Geom::PathVector::iterator it_pv = k->path_vector->begin(); it_pv != k->path_vector->end(); ++it_pv) {
617 if (it_pv->closed()) {
618 // Get the closing linesegment and convert it to a path
619 Geom::Path cls;
620 cls.close(false);
621 cls.append(it_pv->back_closed());
622 // Intersect that closing path with the constrained path
623 Geom::Crossings cs = Geom::crossings(constraint_path.front(), cls);
624 // Reconstruct and store the points of intersection
625 index = 0; // assuming the constraint path vector has only one path
626 for (Geom::Crossings::const_iterator m = cs.begin(); m != cs.end(); m++) {
627 intersections.push_back(constraint_path[index].pointAt((*m).ta));
628 }
629 }
630 }
632 // Convert the collected points of intersection to snapped points
633 for (std::vector<Geom::Point>::iterator p_inters = intersections.begin(); p_inters != intersections.end(); p_inters++) {
634 // Convert to desktop coordinates
635 (*p_inters) = _snapmanager->getDesktop()->doc2dt(*p_inters);
636 // Construct a snapped point
637 Geom::Coord dist = Geom::L2(p.getPoint() - *p_inters);
638 SnappedPoint s = SnappedPoint(*p_inters, p.getSourceType(), p.getSourceNum(), k->target_type, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true, k->target_bbox);;
639 // Store the snapped point
640 if (dist <= tolerance) { // If the intersection is within snapping range, then we might snap to it
641 sc.points.push_back(s);
642 }
643 }
644 }
645 }
646 }
649 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
650 Inkscape::SnapCandidatePoint const &p,
651 Geom::OptRect const &bbox_to_snap,
652 std::vector<SPItem const *> const *it,
653 std::vector<SnapCandidatePoint> *unselected_nodes) const
654 {
655 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(p.getSourceType()) == false ) {
656 return;
657 }
659 /* Get a list of all the SPItems that we will try to snap to */
660 if (p.getSourceNum() <= 0) {
661 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p.getPoint(), p.getPoint());
662 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, p.getSourceNum() <= 0, local_bbox_to_snap, false, Geom::identity());
663 }
665 // TODO: Argh, UGLY! Get rid of this here, move this logic to the snap manager
666 bool snap_nodes = (_snapmanager->snapprefs.getSnapModeNode() && (
667 _snapmanager->snapprefs.getSnapToItemNode() ||
668 _snapmanager->snapprefs.getSnapSmoothNodes() ||
669 _snapmanager->snapprefs.getSnapLineMidpoints() ||
670 _snapmanager->snapprefs.getSnapObjectMidpoints()
671 )) || (_snapmanager->snapprefs.getSnapModeBBox() && (
672 _snapmanager->snapprefs.getSnapToBBoxNode() ||
673 _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() ||
674 _snapmanager->snapprefs.getSnapBBoxMidpoints()
675 )) || (_snapmanager->snapprefs.getSnapModeBBoxOrNodes() && (
676 _snapmanager->snapprefs.getIncludeItemCenter() ||
677 _snapmanager->snapprefs.getSnapToPageBorder()
678 ));
680 if (snap_nodes) {
681 _snapNodes(sc, p, unselected_nodes);
682 }
684 if ((_snapmanager->snapprefs.getSnapModeNode() && _snapmanager->snapprefs.getSnapToItemPath()) ||
685 (_snapmanager->snapprefs.getSnapModeBBox() && _snapmanager->snapprefs.getSnapToBBoxPath()) ||
686 (_snapmanager->snapprefs.getSnapModeBBoxOrNodes() && _snapmanager->snapprefs.getSnapToPageBorder())) {
687 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
688 if (n > 0) {
689 /* While editing a path in the node tool, findCandidates must ignore that path because
690 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
691 * That path must not be ignored however when snapping to the paths, so we add it here
692 * manually when applicable
693 */
694 SPPath *path = NULL;
695 if (it != NULL) {
696 if (it->size() == 1 && SP_IS_PATH(*it->begin())) {
697 path = SP_PATH(*it->begin());
698 } // else: *it->begin() might be a SPGroup, e.g. when editing a LPE of text that has been converted to a group of paths
699 // as reported in bug #356743. In that case we can just ignore it, i.e. not snap to this item
700 }
701 _snapPaths(sc, p, unselected_nodes, path);
702 } else {
703 _snapPaths(sc, p, NULL, NULL);
704 }
705 }
706 }
708 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
709 Inkscape::SnapCandidatePoint const &p,
710 Geom::OptRect const &bbox_to_snap,
711 SnapConstraint const &c,
712 std::vector<SPItem const *> const *it,
713 std::vector<SnapCandidatePoint> *unselected_nodes) const
714 {
715 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(p.getSourceType()) == false) {
716 return;
717 }
719 // project the mouse pointer onto the constraint. Only the projected point will be considered for snapping
720 Geom::Point pp = c.projection(p.getPoint());
722 /* Get a list of all the SPItems that we will try to snap to */
723 if (p.getSourceNum() <= 0) {
724 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(pp, pp);
725 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, p.getSourceNum() <= 0, local_bbox_to_snap, false, Geom::identity());
726 }
728 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
729 // This is useful for example when scaling an object while maintaining a fixed aspect ratio. It's
730 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
732 // TODO: Argh, UGLY! Get rid of this here, move this logic to the snap manager
733 bool snap_nodes = (_snapmanager->snapprefs.getSnapModeNode() && (
734 _snapmanager->snapprefs.getSnapToItemNode() ||
735 _snapmanager->snapprefs.getSnapSmoothNodes() ||
736 _snapmanager->snapprefs.getSnapLineMidpoints() ||
737 _snapmanager->snapprefs.getSnapObjectMidpoints()
738 )) || (_snapmanager->snapprefs.getSnapModeBBox() && (
739 _snapmanager->snapprefs.getSnapToBBoxNode() ||
740 _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() ||
741 _snapmanager->snapprefs.getSnapBBoxMidpoints()
742 )) || (_snapmanager->snapprefs.getSnapModeBBoxOrNodes() && (
743 _snapmanager->snapprefs.getIncludeItemCenter() ||
744 _snapmanager->snapprefs.getSnapToPageBorder()
745 ));
747 if (snap_nodes) {
748 _snapNodes(sc, p, unselected_nodes, c, pp);
749 }
751 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
752 _snapPathsConstrained(sc, p, c, pp);
753 }
754 }
757 // This method is used to snap a guide to nodes, while dragging the guide around
758 void Inkscape::ObjectSnapper::guideFreeSnap(SnappedConstraints &sc,
759 Geom::Point const &p,
760 Geom::Point const &guide_normal) const
761 {
762 /* Get a list of all the SPItems that we will try to snap to */
763 std::vector<SPItem*> cand;
764 std::vector<SPItem const *> const it; //just an empty list
766 _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), false, Geom::identity());
767 _snapTranslatingGuide(sc, p, guide_normal);
769 }
771 // This method is used to snap the origin of a guide to nodes/paths, while dragging the origin along the guide
772 void Inkscape::ObjectSnapper::guideConstrainedSnap(SnappedConstraints &sc,
773 Geom::Point const &p,
774 Geom::Point const &guide_normal,
775 SnapConstraint const &/*c*/) const
776 {
777 /* Get a list of all the SPItems that we will try to snap to */
778 std::vector<SPItem*> cand;
779 std::vector<SPItem const *> const it; //just an empty list
781 _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), false, Geom::identity());
782 _snapTranslatingGuide(sc, p, guide_normal);
784 }
786 /**
787 * \return true if this Snapper will snap at least one kind of point.
788 */
789 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
790 {
791 bool snap_to_something = (_snapmanager->snapprefs.getSnapModeNode() && (
792 _snapmanager->snapprefs.getSnapToItemPath() ||
793 _snapmanager->snapprefs.getSnapToItemNode() ||
794 _snapmanager->snapprefs.getSnapSmoothNodes() ||
795 _snapmanager->snapprefs.getSnapLineMidpoints() ||
796 _snapmanager->snapprefs.getSnapObjectMidpoints()
797 )) || (_snapmanager->snapprefs.getSnapModeBBox() && (
798 _snapmanager->snapprefs.getSnapToBBoxPath() ||
799 _snapmanager->snapprefs.getSnapToBBoxNode() ||
800 _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() ||
801 _snapmanager->snapprefs.getSnapBBoxMidpoints()
802 )) || (_snapmanager->snapprefs.getSnapModeBBoxOrNodes() && (
803 _snapmanager->snapprefs.getSnapToPageBorder() ||
804 _snapmanager->snapprefs.getIncludeItemCenter()
805 ));
807 return (_snap_enabled && snap_to_something);
808 }
810 void Inkscape::ObjectSnapper::_clear_paths() const
811 {
812 for (std::vector<Inkscape::SnapCandidatePath >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
813 delete k->path_vector;
814 }
815 _paths_to_snap_to->clear();
816 }
818 Geom::PathVector* Inkscape::ObjectSnapper::_getBorderPathv() const
819 {
820 Geom::Rect const border_rect = Geom::Rect(Geom::Point(0,0), Geom::Point(sp_document_width(_snapmanager->getDocument()),sp_document_height(_snapmanager->getDocument())));
821 return _getPathvFromRect(border_rect);
822 }
824 Geom::PathVector* Inkscape::ObjectSnapper::_getPathvFromRect(Geom::Rect const rect) const
825 {
826 SPCurve const *border_curve = SPCurve::new_from_rect(rect, true);
827 if (border_curve) {
828 Geom::PathVector *dummy = new Geom::PathVector(border_curve->get_pathvector());
829 return dummy;
830 } else {
831 return NULL;
832 }
833 }
835 void Inkscape::ObjectSnapper::_getBorderNodes(std::vector<SnapCandidatePoint> *points) const
836 {
837 Geom::Coord w = sp_document_width(_snapmanager->getDocument());
838 Geom::Coord h = sp_document_height(_snapmanager->getDocument());
839 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(0,0), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
840 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(0,h), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
841 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(w,h), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
842 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(w,0), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
843 }
845 void Inkscape::getBBoxPoints(Geom::OptRect const bbox,
846 std::vector<SnapCandidatePoint> *points,
847 bool const /*isTarget*/,
848 bool const includeCorners,
849 bool const includeLineMidpoints,
850 bool const includeObjectMidpoints)
851 {
852 if (bbox) {
853 // collect the corners of the bounding box
854 for ( unsigned k = 0 ; k < 4 ; k++ ) {
855 if (includeCorners) {
856 points->push_back(Inkscape::SnapCandidatePoint(bbox->corner(k), Inkscape::SNAPSOURCE_BBOX_CORNER, -1, Inkscape::SNAPTARGET_BBOX_CORNER, *bbox));
857 }
858 // optionally, collect the midpoints of the bounding box's edges too
859 if (includeLineMidpoints) {
860 points->push_back(Inkscape::SnapCandidatePoint((bbox->corner(k) + bbox->corner((k+1) % 4))/2, Inkscape::SNAPSOURCE_BBOX_EDGE_MIDPOINT, -1, Inkscape::SNAPTARGET_BBOX_EDGE_MIDPOINT, *bbox));
861 }
862 }
863 if (includeObjectMidpoints) {
864 points->push_back(Inkscape::SnapCandidatePoint(bbox->midpoint(), Inkscape::SNAPSOURCE_BBOX_MIDPOINT, -1, Inkscape::SNAPTARGET_BBOX_MIDPOINT, *bbox));
865 }
866 }
867 }
869 /*
870 Local Variables:
871 mode:c++
872 c-file-style:"stroustrup"
873 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
874 indent-tabs-mode:nil
875 fill-column:99
876 End:
877 */
878 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :