1 /**
2 * \file object-snapper.cpp
3 * \brief Snapping things to objects.
4 *
5 * Authors:
6 * Carl Hetherington <inkscape@carlh.net>
7 * Diederik van Lierop <mail@diedenrezi.nl>
8 *
9 * Copyright (C) 2005 - 2008 Authors
10 *
11 * Released under GNU GPL, read the file 'COPYING' for more information
12 */
14 #include "svg/svg.h"
15 #include <2geom/path-intersection.h>
16 #include <2geom/point.h>
17 #include <2geom/rect.h>
18 #include <2geom/line.h>
19 #include "document.h"
20 #include "sp-namedview.h"
21 #include "sp-image.h"
22 #include "sp-item-group.h"
23 #include "sp-item.h"
24 #include "sp-use.h"
25 #include "display/curve.h"
26 #include "inkscape.h"
27 #include "preferences.h"
28 #include "sp-text.h"
29 #include "sp-flowtext.h"
30 #include "text-editing.h"
31 #include "sp-clippath.h"
32 #include "sp-mask.h"
33 #include "helper/geom-curves.h"
34 #include "desktop.h"
36 Inkscape::ObjectSnapper::ObjectSnapper(SnapManager *sm, Geom::Coord const d)
37 : Snapper(sm, d)
38 {
39 _candidates = new std::vector<SnapCandidateItem>;
40 _points_to_snap_to = new std::vector<Inkscape::SnapCandidatePoint>;
41 _paths_to_snap_to = new std::vector<Inkscape::SnapCandidatePath >;
42 }
44 Inkscape::ObjectSnapper::~ObjectSnapper()
45 {
46 _candidates->clear();
47 delete _candidates;
49 _points_to_snap_to->clear();
50 delete _points_to_snap_to;
52 _clear_paths();
53 delete _paths_to_snap_to;
54 }
56 /**
57 * \return Snap tolerance (desktop coordinates); depends on current zoom so that it's always the same in screen pixels
58 */
59 Geom::Coord Inkscape::ObjectSnapper::getSnapperTolerance() const
60 {
61 SPDesktop const *dt = _snapmanager->getDesktop();
62 double const zoom = dt ? dt->current_zoom() : 1;
63 return _snapmanager->snapprefs.getObjectTolerance() / zoom;
64 }
66 bool Inkscape::ObjectSnapper::getSnapperAlwaysSnap() const
67 {
68 return _snapmanager->snapprefs.getObjectTolerance() == 10000; //TODO: Replace this threshold of 10000 by a constant; see also tolerance-slider.cpp
69 }
71 /**
72 * Find all items within snapping range.
73 * \param parent Pointer to the document's root, or to a clipped path or mask object
74 * \param it List of items to ignore
75 * \param bbox_to_snap Bounding box hulling the whole bunch of points, all from the same selection and having the same transformation
76 * \param DimensionToSnap Snap in X, Y, or both directions.
77 */
79 void Inkscape::ObjectSnapper::_findCandidates(SPObject* parent,
80 std::vector<SPItem const *> const *it,
81 bool const &first_point,
82 Geom::Rect const &bbox_to_snap,
83 DimensionToSnap const snap_dim,
84 bool const clip_or_mask,
85 Geom::Matrix const additional_affine) const // transformation of the item being clipped / masked
86 {
87 bool const c1 = (snap_dim == TRANSL_SNAP_XY) && ThisSnapperMightSnap();
88 bool const c2 = (snap_dim != TRANSL_SNAP_XY) && GuidesMightSnap();
90 if (!(c1 || c2)) {
91 return;
92 }
94 if (first_point) {
95 _candidates->clear();
96 }
98 Geom::Rect bbox_to_snap_incl = bbox_to_snap; // _incl means: will include the snapper tolerance
99 bbox_to_snap_incl.expandBy(getSnapperTolerance()); // see?
101 for (SPObject* o = parent->first_child(); o != NULL; o = SP_OBJECT_NEXT(o)) {
102 g_assert(_snapmanager->getDesktop() != NULL);
103 if (SP_IS_ITEM(o) && !(_snapmanager->getDesktop()->itemIsHidden(SP_ITEM(o)) && !clip_or_mask)) {
104 // Snapping to items in a locked layer is allowed
105 // Don't snap to hidden objects, unless they're a clipped path or a mask
106 /* See if this item is on the ignore list */
107 std::vector<SPItem const *>::const_iterator i;
108 if (it != NULL) {
109 i = it->begin();
110 while (i != it->end() && *i != o) {
111 i++;
112 }
113 }
115 if (it == NULL || i == it->end()) {
116 SPItem *item = SP_ITEM(o);
117 if (item) {
118 SPObject *obj = NULL;
119 if (!clip_or_mask) { // cannot clip or mask more than once
120 // The current item is not a clipping path or a mask, but might
121 // still be the subject of clipping or masking itself ; if so, then
122 // we should also consider that path or mask for snapping to
123 obj = SP_OBJECT(item->clip_ref->getObject());
124 if (obj) {
125 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, item->i2doc_affine());
126 }
127 obj = SP_OBJECT(item->mask_ref->getObject());
128 if (obj) {
129 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, item->i2doc_affine());
130 }
131 }
132 }
134 if (SP_IS_GROUP(o)) {
135 _findCandidates(o, it, false, bbox_to_snap, snap_dim, clip_or_mask, additional_affine);
136 } else {
137 Geom::OptRect bbox_of_item = Geom::Rect();
138 if (clip_or_mask) {
139 // Oh oh, this will get ugly. We cannot use sp_item_i2d_affine directly because we need to
140 // insert an additional transformation in document coordinates (code copied from sp_item_i2d_affine)
141 item->invoke_bbox(bbox_of_item,
142 item->i2doc_affine() * additional_affine * _snapmanager->getDesktop()->doc2dt(),
143 true);
144 } else {
145 item->invoke_bbox( bbox_of_item, item->i2d_affine(), true);
146 }
147 if (bbox_of_item) {
148 // See if the item is within range
149 if (bbox_to_snap_incl.intersects(*bbox_of_item)) {
150 // This item is within snapping range, so record it as a candidate
151 _candidates->push_back(SnapCandidateItem(item, clip_or_mask, additional_affine));
152 // For debugging: print the id of the candidate to the console
153 // SPObject *obj = (SPObject*)item;
154 // std::cout << "Snap candidate added: " << obj->getId() << std::endl;
155 }
156 }
157 }
158 }
159 }
160 }
161 }
164 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::SnapSourceType const &t,
165 bool const &first_point) const
166 {
167 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
168 // e.g. when translating an item using the selector tool, then we will only do this for the
169 // first point and store the collection for later use. This significantly improves the performance
170 if (first_point) {
171 _points_to_snap_to->clear();
173 // Determine the type of bounding box we should snap to
174 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
176 bool p_is_a_node = t & Inkscape::SNAPSOURCE_NODE_CATEGORY;
177 bool p_is_a_bbox = t & Inkscape::SNAPSOURCE_BBOX_CATEGORY;
178 bool p_is_other = t & Inkscape::SNAPSOURCE_OTHER_CATEGORY;
180 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
181 g_assert(!((p_is_a_node && p_is_a_bbox) || (p_is_a_bbox && p_is_other) || (p_is_a_node && p_is_other)));
183 if (_snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()) {
184 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
185 bool prefs_bbox = prefs->getBool("/tools/bounding_box");
186 bbox_type = !prefs_bbox ?
187 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
188 }
190 // Consider the page border for snapping to
191 if (_snapmanager->snapprefs.getSnapToPageBorder()) {
192 _getBorderNodes(_points_to_snap_to);
193 }
195 for (std::vector<SnapCandidateItem>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
196 //Geom::Matrix i2doc(Geom::identity());
197 SPItem *root_item = (*i).item;
198 if (SP_IS_USE((*i).item)) {
199 root_item = sp_use_root(SP_USE((*i).item));
200 }
201 g_return_if_fail(root_item);
203 //Collect all nodes so we can snap to them
204 if (p_is_a_node || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node) || p_is_other) {
205 // Note: there are two ways in which intersections are considered:
206 // Method 1: Intersections are calculated for each shape individually, for both the
207 // snap source and snap target (see sp_shape_snappoints)
208 // Method 2: Intersections are calculated for each curve or line that we've snapped to, i.e. only for
209 // the target (see the intersect() method in the SnappedCurve and SnappedLine classes)
210 // Some differences:
211 // - Method 1 doesn't find intersections within a set of multiple objects
212 // - Method 2 only works for targets
213 // When considering intersections as snap targets:
214 // - Method 1 only works when snapping to nodes, whereas
215 // - Method 2 only works when snapping to paths
216 // - There will be performance differences too!
217 // If both methods are being used simultaneously, then this might lead to duplicate targets!
219 // Well, here we will be looking for snap TARGETS. Both methods can therefore be used.
220 // When snapping to paths, we will get a collection of snapped lines and snapped curves. findBestSnap() will
221 // go hunting for intersections (but only when asked to in the prefs of course). In that case we can just
222 // temporarily block the intersections in sp_item_snappoints, we don't need duplicates. If we're not snapping to
223 // paths though but only to item nodes then we should still look for the intersections in sp_item_snappoints()
224 bool old_pref = _snapmanager->snapprefs.getSnapIntersectionCS();
225 if (_snapmanager->snapprefs.getSnapToItemPath()) {
226 _snapmanager->snapprefs.setSnapIntersectionCS(false);
227 }
229 root_item->getSnappoints(*_points_to_snap_to, &_snapmanager->snapprefs);
231 if (_snapmanager->snapprefs.getSnapToItemPath()) {
232 _snapmanager->snapprefs.setSnapIntersectionCS(old_pref);
233 }
234 }
236 //Collect the bounding box's corners so we can snap to them
237 if (p_is_a_bbox || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_bbox) || p_is_other) {
238 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
239 // of the item AND the bbox of the clipping path at the same time
240 if (!(*i).clip_or_mask) {
241 Geom::OptRect b = root_item->getBboxDesktop(bbox_type);
242 getBBoxPoints(b, _points_to_snap_to, true, _snapmanager->snapprefs.getSnapToBBoxNode(), _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints(), _snapmanager->snapprefs.getSnapBBoxMidpoints());
243 }
244 }
245 }
246 }
247 }
249 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
250 Inkscape::SnapCandidatePoint const &p,
251 std::vector<SnapCandidatePoint> *unselected_nodes) const
252 {
253 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
255 _collectNodes(p.getSourceType(), p.getSourceNum() == 0);
257 if (unselected_nodes != NULL) {
258 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
259 }
261 SnappedPoint s;
262 bool success = false;
264 for (std::vector<SnapCandidatePoint>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
265 Geom::Coord dist = Geom::L2((*k).getPoint() - p.getPoint());
266 if (dist < getSnapperTolerance() && dist < s.getSnapDistance()) {
267 s = SnappedPoint((*k).getPoint(), p.getSourceType(), p.getSourceNum(), (*k).getTargetType(), dist, getSnapperTolerance(), getSnapperAlwaysSnap(), false, true, (*k).getTargetBBox());
268 success = true;
269 }
270 }
272 if (success) {
273 sc.points.push_back(s);
274 }
275 }
277 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
278 Geom::Point const &p,
279 Geom::Point const &guide_normal) const
280 {
281 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
282 _collectNodes(SNAPSOURCE_GUIDE, true);
284 // Although we won't snap to paths here (which would give us under constrained snaps) we can still snap to intersections of paths.
285 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
286 _collectPaths(Inkscape::SnapCandidatePoint(p, SNAPSOURCE_GUIDE), true);
287 _snapPaths(sc, Inkscape::SnapCandidatePoint(p, SNAPSOURCE_GUIDE), NULL, NULL);
288 // The paths themselves should be discarded in findBestSnap(), as we should only snap to their intersections
289 }
291 SnappedPoint s;
293 Geom::Coord tol = getSnapperTolerance();
295 for (std::vector<SnapCandidatePoint>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
296 // Project each node (*k) on the guide line (running through point p)
297 Geom::Point p_proj = Geom::projection((*k).getPoint(), Geom::Line(p, p + Geom::rot90(guide_normal)));
298 Geom::Coord dist = Geom::L2((*k).getPoint() - p_proj); // distance from node to the guide
299 Geom::Coord dist2 = Geom::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
300 if ((dist < tol && dist2 < tol) || getSnapperAlwaysSnap()) {
301 s = SnappedPoint((*k).getPoint(), SNAPSOURCE_GUIDE, 0, (*k).getTargetType(), dist, tol, getSnapperAlwaysSnap(), false, true, (*k).getTargetBBox());
302 sc.points.push_back(s);
303 }
304 }
305 }
308 /**
309 * Returns index of first NR_END bpath in array.
310 */
312 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::SnapCandidatePoint const &p,
313 bool const &first_point) const
314 {
315 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
316 // e.g. when translating an item using the selector tool, then we will only do this for the
317 // first point and store the collection for later use. This significantly improves the performance
318 if (first_point) {
319 _clear_paths();
321 // Determine the type of bounding box we should snap to
322 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
324 bool p_is_a_node = p.getSourceType() & Inkscape::SNAPSOURCE_NODE_CATEGORY;
325 bool p_is_other = p.getSourceType() & Inkscape::SNAPSOURCE_OTHER_CATEGORY;
327 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
328 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
329 int prefs_bbox = prefs->getBool("/tools/bounding_box", 0);
330 bbox_type = !prefs_bbox ?
331 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
332 }
334 // Consider the page border for snapping
335 if (_snapmanager->snapprefs.getSnapToPageBorder()) {
336 Geom::PathVector *border_path = _getBorderPathv();
337 if (border_path != NULL) {
338 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(border_path, SNAPTARGET_PAGE_BORDER, Geom::OptRect()));
339 }
340 }
342 for (std::vector<SnapCandidateItem>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
344 /* Transform the requested snap point to this item's coordinates */
345 Geom::Matrix i2doc(Geom::identity());
346 SPItem *root_item = NULL;
347 /* We might have a clone at hand, so make sure we get the root item */
348 if (SP_IS_USE((*i).item)) {
349 i2doc = sp_use_get_root_transform(SP_USE((*i).item));
350 root_item = sp_use_root(SP_USE((*i).item));
351 g_return_if_fail(root_item);
352 } else {
353 i2doc = (*i).item->i2doc_affine();
354 root_item = (*i).item;
355 }
357 //Build a list of all paths considered for snapping to
359 //Add the item's path to snap to
360 if (_snapmanager->snapprefs.getSnapToItemPath()) {
361 if (p_is_other || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node)) {
362 // Snapping to the path of characters is very cool, but for a large
363 // chunk of text this will take ages! So limit snapping to text paths
364 // containing max. 240 characters. Snapping the bbox will not be affected
365 bool very_lenghty_prose = false;
366 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
367 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
368 }
369 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
370 // which corresponds to a lag of 500 msec. This is for snapping a rect
371 // to a single line of text.
373 // Snapping for example to a traced bitmap is also very stressing for
374 // the CPU, so we'll only snap to paths having no more than 500 nodes
375 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
376 bool very_complex_path = false;
377 if (SP_IS_PATH(root_item)) {
378 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
379 }
381 if (!very_lenghty_prose && !very_complex_path) {
382 SPCurve *curve = curve_for_item(root_item);
383 if (curve) {
384 // We will get our own copy of the path, which must be freed at some point
385 Geom::PathVector *borderpathv = pathvector_for_curve(root_item, curve, true, true, Geom::identity(), (*i).additional_affine);
386 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(borderpathv, SNAPTARGET_PATH, Geom::OptRect())); // Perhaps for speed, get a reference to the Geom::pathvector, and store the transformation besides it.
387 curve->unref();
388 }
389 }
390 }
391 }
393 //Add the item's bounding box to snap to
394 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
395 if (p_is_other || !(_snapmanager->snapprefs.getStrictSnapping() && p_is_a_node)) {
396 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
397 // of the item AND the bbox of the clipping path at the same time
398 if (!(*i).clip_or_mask) {
399 Geom::OptRect rect;
400 root_item->invoke_bbox( rect, i2doc, TRUE, bbox_type);
401 if (rect) {
402 Geom::PathVector *path = _getPathvFromRect(*rect);
403 rect = root_item->getBboxDesktop(bbox_type);
404 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(path, SNAPTARGET_BBOX_EDGE, rect));
405 }
406 }
407 }
408 }
409 }
410 }
411 }
413 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
414 Inkscape::SnapCandidatePoint const &p,
415 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
416 SPPath const *selected_path) const
417 {
418 _collectPaths(p, p.getSourceNum() == 0);
419 // Now we can finally do the real snapping, using the paths collected above
421 g_assert(_snapmanager->getDesktop() != NULL);
422 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p.getPoint());
424 bool const node_tool_active = _snapmanager->snapprefs.getSnapToItemPath() && selected_path != NULL;
426 if (p.getSourceNum() == 0) {
427 /* findCandidates() is used for snapping to both paths and nodes. It ignores the path that is
428 * currently being edited, because that path requires special care: when snapping to nodes
429 * only the unselected nodes of that path should be considered, and these will be passed on separately.
430 * This path must not be ignored however when snapping to the paths, so we add it here
431 * manually when applicable.
432 * */
433 if (node_tool_active) {
434 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
435 if (curve) {
436 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
437 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(pathv, SNAPTARGET_PATH, Geom::OptRect(), true));
438 curve->unref();
439 }
440 }
441 }
443 int num_path = 0;
444 int num_segm = 0;
446 for (std::vector<Inkscape::SnapCandidatePath >::const_iterator it_p = _paths_to_snap_to->begin(); it_p != _paths_to_snap_to->end(); it_p++) {
447 bool const being_edited = node_tool_active && (*it_p).currently_being_edited;
448 //if true then this pathvector it_pv is currently being edited in the node tool
450 for(Geom::PathVector::iterator it_pv = (it_p->path_vector)->begin(); it_pv != (it_p->path_vector)->end(); ++it_pv) {
451 // Find a nearest point for each curve within this path
452 // n curves will return n time values with 0 <= t <= 1
453 std::vector<double> anp = (*it_pv).nearestPointPerCurve(p_doc);
455 std::vector<double>::const_iterator np = anp.begin();
456 unsigned int index = 0;
457 for (; np != anp.end(); np++, index++) {
458 Geom::Curve const *curve = &((*it_pv).at_index(index));
459 Geom::Point const sp_doc = curve->pointAt(*np);
461 bool c1 = true;
462 bool c2 = true;
463 if (being_edited) {
464 /* If the path is being edited, then we should only snap though to stationary pieces of the path
465 * and not to the pieces that are being dragged around. This way we avoid
466 * self-snapping. For this we check whether the nodes at both ends of the current
467 * piece are unselected; if they are then this piece must be stationary
468 */
469 g_assert(unselected_nodes != NULL);
470 Geom::Point start_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(0));
471 Geom::Point end_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(1));
472 c1 = isUnselectedNode(start_pt, unselected_nodes);
473 c2 = isUnselectedNode(end_pt, unselected_nodes);
474 /* Unfortunately, this might yield false positives for coincident nodes. Inkscape might therefore mistakenly
475 * snap to path segments that are not stationary. There are at least two possible ways to overcome this:
476 * - Linking the individual nodes of the SPPath we have here, to the nodes of the NodePath::SubPath class as being
477 * used in sp_nodepath_selected_nodes_move. This class has a member variable called "selected". For this the nodes
478 * should be in the exact same order for both classes, so we can index them
479 * - Replacing the SPPath being used here by the the NodePath::SubPath class; but how?
480 */
481 }
483 Geom::Point const sp_dt = _snapmanager->getDesktop()->doc2dt(sp_doc);
484 if (!being_edited || (c1 && c2)) {
485 Geom::Coord const dist = Geom::distance(sp_doc, p_doc);
486 if (dist < getSnapperTolerance()) {
487 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));
488 }
489 }
490 }
491 num_segm++;
492 } // End of: for (Geom::PathVector::iterator ....)
493 num_path++;
494 }
495 }
497 /* Returns true if point is coincident with one of the unselected nodes */
498 bool Inkscape::ObjectSnapper::isUnselectedNode(Geom::Point const &point, std::vector<Inkscape::SnapCandidatePoint> const *unselected_nodes) const
499 {
500 if (unselected_nodes == NULL) {
501 return false;
502 }
504 if (unselected_nodes->size() == 0) {
505 return false;
506 }
508 for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
509 if (Geom::L2(point - (*i).getPoint()) < 1e-4) {
510 return true;
511 }
512 }
514 return false;
515 }
517 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
518 Inkscape::SnapCandidatePoint const &p,
519 ConstraintLine const &c) const
520 {
522 _collectPaths(p, p.getSourceNum() == 0);
524 // Now we can finally do the real snapping, using the paths collected above
526 g_assert(_snapmanager->getDesktop() != NULL);
527 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p.getPoint());
529 Geom::Point direction_vector = c.getDirection();
530 if (!is_zero(direction_vector)) {
531 direction_vector = Geom::unit_vector(direction_vector);
532 }
534 // The intersection point of the constraint line with any path,
535 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
536 // The distance between those points is twice the snapping tolerance
537 Geom::Point const p_proj_on_cl = p.getPoint(); // projection has already been taken care of in constrainedSnap in the snapmanager;
538 Geom::Point const p_min_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
539 Geom::Point const p_max_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
541 Geom::Path cl;
542 std::vector<Geom::Path> clv;
543 cl.start(p_min_on_cl);
544 cl.appendNew<Geom::LineSegment>(p_max_on_cl);
545 clv.push_back(cl);
547 for (std::vector<Inkscape::SnapCandidatePath >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
548 if (k->path_vector) {
549 Geom::CrossingSet cs = Geom::crossings(clv, *(k->path_vector));
550 if (cs.size() > 0) {
551 // We need only the first element of cs, because cl is only a single straight linesegment
552 // This first element contains a vector filled with crossings of cl with k->first
553 for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
554 if ((*m).ta >= 0 && (*m).ta <= 1 ) {
555 // Reconstruct the point of intersection
556 Geom::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
557 // When it's within snapping range, then return it
558 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
559 Geom::Coord dist = Geom::L2(_snapmanager->getDesktop()->dt2doc(p_proj_on_cl) - p_inters);
560 SnappedPoint s(_snapmanager->getDesktop()->doc2dt(p_inters), p.getSourceType(), p.getSourceNum(), k->target_type, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true, k->target_bbox);
561 sc.points.push_back(s);
562 }
563 }
564 }
565 }
566 }
567 }
570 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
571 Inkscape::SnapCandidatePoint const &p,
572 Geom::OptRect const &bbox_to_snap,
573 std::vector<SPItem const *> const *it,
574 std::vector<SnapCandidatePoint> *unselected_nodes) const
575 {
576 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(p.getSourceType()) == false ) {
577 return;
578 }
580 /* Get a list of all the SPItems that we will try to snap to */
581 if (p.getSourceNum() == 0) {
582 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p.getPoint(), p.getPoint());
583 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, p.getSourceNum() == 0, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
584 }
586 if (_snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapSmoothNodes()
587 || _snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapToPageBorder()
588 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
589 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
590 || _snapmanager->snapprefs.getIncludeItemCenter()) {
591 _snapNodes(sc, p, unselected_nodes);
592 }
594 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
595 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
596 if (n > 0) {
597 /* While editing a path in the node tool, findCandidates must ignore that path because
598 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
599 * That path must not be ignored however when snapping to the paths, so we add it here
600 * manually when applicable
601 */
602 SPPath *path = NULL;
603 if (it != NULL) {
604 if (it->size() == 1 && SP_IS_PATH(*it->begin())) {
605 path = SP_PATH(*it->begin());
606 } // else: *it->begin() might be a SPGroup, e.g. when editing a LPE of text that has been converted to a group of paths
607 // as reported in bug #356743. In that case we can just ignore it, i.e. not snap to this item
608 }
609 _snapPaths(sc, p, unselected_nodes, path);
610 } else {
611 _snapPaths(sc, p, NULL, NULL);
612 }
613 }
614 }
616 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
617 Inkscape::SnapCandidatePoint const &p,
618 Geom::OptRect const &bbox_to_snap,
619 ConstraintLine const &c,
620 std::vector<SPItem const *> const *it) const
621 {
622 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(p.getSourceType()) == false) {
623 return;
624 }
626 /* Get a list of all the SPItems that we will try to snap to */
627 if (p.getSourceNum() == 0) {
628 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p.getPoint(), p.getPoint());
629 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, p.getSourceNum() == 0, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
630 }
632 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
633 // This is useful for example when scaling an object while maintaining a fixed aspect ratio. It's
634 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
636 // When snapping to objects, we either snap to their nodes or their paths. It is however very
637 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
638 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
639 // so we will more or less snap to them anyhow.
641 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
642 _snapPathsConstrained(sc, p, c);
643 }
644 }
647 // This method is used to snap a guide to nodes, while dragging the guide around
648 void Inkscape::ObjectSnapper::guideFreeSnap(SnappedConstraints &sc,
649 Geom::Point const &p,
650 Geom::Point const &guide_normal) const
651 {
652 /* Get a list of all the SPItems that we will try to snap to */
653 std::vector<SPItem*> cand;
654 std::vector<SPItem const *> const it; //just an empty list
656 DimensionToSnap snap_dim;
657 if (guide_normal == to_2geom(component_vectors[Geom::Y])) {
658 snap_dim = GUIDE_TRANSL_SNAP_Y;
659 } else if (guide_normal == to_2geom(component_vectors[Geom::X])) {
660 snap_dim = GUIDE_TRANSL_SNAP_X;
661 } else {
662 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
663 }
665 _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), snap_dim, false, Geom::identity());
666 _snapTranslatingGuideToNodes(sc, p, guide_normal);
668 }
670 // This method is used to snap the origin of a guide to nodes/paths, while dragging the origin along the guide
671 void Inkscape::ObjectSnapper::guideConstrainedSnap(SnappedConstraints &sc,
672 Geom::Point const &p,
673 Geom::Point const &guide_normal,
674 ConstraintLine const &/*c*/) const
675 {
676 /* Get a list of all the SPItems that we will try to snap to */
677 std::vector<SPItem*> cand;
678 std::vector<SPItem const *> const it; //just an empty list
680 DimensionToSnap snap_dim;
681 if (guide_normal == to_2geom(component_vectors[Geom::Y])) {
682 snap_dim = GUIDE_TRANSL_SNAP_Y;
683 } else if (guide_normal == to_2geom(component_vectors[Geom::X])) {
684 snap_dim = GUIDE_TRANSL_SNAP_X;
685 } else {
686 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
687 }
689 _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), snap_dim, false, Geom::identity());
690 _snapTranslatingGuideToNodes(sc, p, guide_normal);
692 }
694 /**
695 * \return true if this Snapper will snap at least one kind of point.
696 */
697 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
698 {
699 bool snap_to_something = _snapmanager->snapprefs.getSnapToItemPath()
700 || _snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapSmoothNodes()
701 || _snapmanager->snapprefs.getSnapToBBoxPath()
702 || _snapmanager->snapprefs.getSnapToBBoxNode()
703 || _snapmanager->snapprefs.getSnapToPageBorder()
704 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
705 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
706 || _snapmanager->snapprefs.getIncludeItemCenter();
708 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeBBoxOrNodes() && snap_to_something);
709 }
711 bool Inkscape::ObjectSnapper::GuidesMightSnap() const // almost the same as ThisSnapperMightSnap above, but only looking at points (and not paths)
712 {
713 bool snap_to_something = _snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapSmoothNodes()
714 || _snapmanager->snapprefs.getSnapToPageBorder()
715 || (_snapmanager->snapprefs.getSnapModeBBox() && _snapmanager->snapprefs.getSnapToBBoxNode())
716 || (_snapmanager->snapprefs.getSnapModeBBox() && (_snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()))
717 || (_snapmanager->snapprefs.getSnapModeNode() && (_snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()))
718 || (_snapmanager->snapprefs.getSnapModeNode() && _snapmanager->snapprefs.getIncludeItemCenter())
719 || (_snapmanager->snapprefs.getSnapModeNode() && (_snapmanager->snapprefs.getSnapToItemPath() && _snapmanager->snapprefs.getSnapIntersectionCS()));
721 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeGuide() && snap_to_something);
722 }
724 void Inkscape::ObjectSnapper::_clear_paths() const
725 {
726 for (std::vector<Inkscape::SnapCandidatePath >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
727 delete k->path_vector;
728 }
729 _paths_to_snap_to->clear();
730 }
732 Geom::PathVector* Inkscape::ObjectSnapper::_getBorderPathv() const
733 {
734 Geom::Rect const border_rect = Geom::Rect(Geom::Point(0,0), Geom::Point((_snapmanager->getDocument())->getWidth(),(_snapmanager->getDocument())->getHeight()));
735 return _getPathvFromRect(border_rect);
736 }
738 Geom::PathVector* Inkscape::ObjectSnapper::_getPathvFromRect(Geom::Rect const rect) const
739 {
740 SPCurve const *border_curve = SPCurve::new_from_rect(rect, true);
741 if (border_curve) {
742 Geom::PathVector *dummy = new Geom::PathVector(border_curve->get_pathvector());
743 return dummy;
744 } else {
745 return NULL;
746 }
747 }
749 void Inkscape::ObjectSnapper::_getBorderNodes(std::vector<SnapCandidatePoint> *points) const
750 {
751 Geom::Coord w = (_snapmanager->getDocument())->getWidth();
752 Geom::Coord h = (_snapmanager->getDocument())->getHeight();
753 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(0,0), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
754 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(0,h), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
755 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(w,h), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
756 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(w,0), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
757 }
759 void Inkscape::getBBoxPoints(Geom::OptRect const bbox,
760 std::vector<SnapCandidatePoint> *points,
761 bool const /*isTarget*/,
762 bool const includeCorners,
763 bool const includeLineMidpoints,
764 bool const includeObjectMidpoints)
765 {
766 if (bbox) {
767 // collect the corners of the bounding box
768 for ( unsigned k = 0 ; k < 4 ; k++ ) {
769 if (includeCorners) {
770 points->push_back(Inkscape::SnapCandidatePoint(bbox->corner(k), Inkscape::SNAPSOURCE_BBOX_CORNER, 0, Inkscape::SNAPTARGET_BBOX_CORNER, *bbox));
771 }
772 // optionally, collect the midpoints of the bounding box's edges too
773 if (includeLineMidpoints) {
774 points->push_back(Inkscape::SnapCandidatePoint((bbox->corner(k) + bbox->corner((k+1) % 4))/2, Inkscape::SNAPSOURCE_BBOX_EDGE_MIDPOINT, 0, Inkscape::SNAPTARGET_BBOX_EDGE_MIDPOINT, *bbox));
775 }
776 }
777 if (includeObjectMidpoints) {
778 points->push_back(Inkscape::SnapCandidatePoint(bbox->midpoint(), Inkscape::SNAPSOURCE_BBOX_MIDPOINT, 0, Inkscape::SNAPTARGET_BBOX_MIDPOINT, *bbox));
779 }
780 }
781 }
783 /*
784 Local Variables:
785 mode:c++
786 c-file-style:"stroustrup"
787 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
788 indent-tabs-mode:nil
789 fill-column:99
790 End:
791 */
792 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :