c1ed08f12f7610b7d0004001078ddcad98423f58
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/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 // This item is within snapping range, so record it as a candidate
153 _candidates->push_back(SnapCandidateItem(item, clip_or_mask, additional_affine));
154 // For debugging: print the id of the candidate to the console
155 // SPObject *obj = (SPObject*)item;
156 // std::cout << "Snap candidate added: " << obj->getId() << std::endl;
157 }
158 }
159 }
160 }
161 }
162 }
163 }
166 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::SnapSourceType const &t,
167 bool const &first_point) const
168 {
169 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
170 // e.g. when translating an item using the selector tool, then we will only do this for the
171 // first point and store the collection for later use. This significantly improves the performance
172 if (first_point) {
173 _points_to_snap_to->clear();
175 // Determine the type of bounding box we should snap to
176 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
178 bool p_is_a_node = t & Inkscape::SNAPSOURCE_NODE_CATEGORY;
179 bool p_is_a_bbox = t & Inkscape::SNAPSOURCE_BBOX_CATEGORY;
180 bool p_is_other = t & Inkscape::SNAPSOURCE_OTHER_CATEGORY;
182 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
183 g_assert(!((p_is_a_node && p_is_a_bbox) || (p_is_a_bbox && p_is_other) || (p_is_a_node && p_is_other)));
185 if (_snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()) {
186 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
187 bool prefs_bbox = prefs->getBool("/tools/bounding_box");
188 bbox_type = !prefs_bbox ?
189 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
190 }
192 // Consider the page border for snapping to
193 if (_snapmanager->snapprefs.getSnapToPageBorder()) {
194 _getBorderNodes(_points_to_snap_to);
195 }
197 for (std::vector<SnapCandidateItem>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
198 //Geom::Matrix i2doc(Geom::identity());
199 SPItem *root_item = (*i).item;
200 if (SP_IS_USE((*i).item)) {
201 root_item = sp_use_root(SP_USE((*i).item));
202 }
203 g_return_if_fail(root_item);
205 //Collect all nodes so we can snap to them
206 if (p_is_a_node || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node) || p_is_other) {
207 // Note: there are two ways in which intersections are considered:
208 // Method 1: Intersections are calculated for each shape individually, for both the
209 // snap source and snap target (see sp_shape_snappoints)
210 // Method 2: Intersections are calculated for each curve or line that we've snapped to, i.e. only for
211 // the target (see the intersect() method in the SnappedCurve and SnappedLine classes)
212 // Some differences:
213 // - Method 1 doesn't find intersections within a set of multiple objects
214 // - Method 2 only works for targets
215 // When considering intersections as snap targets:
216 // - Method 1 only works when snapping to nodes, whereas
217 // - Method 2 only works when snapping to paths
218 // - There will be performance differences too!
219 // If both methods are being used simultaneously, then this might lead to duplicate targets!
221 // Well, here we will be looking for snap TARGETS. Both methods can therefore be used.
222 // When snapping to paths, we will get a collection of snapped lines and snapped curves. findBestSnap() will
223 // go hunting for intersections (but only when asked to in the prefs of course). In that case we can just
224 // temporarily block the intersections in sp_item_snappoints, we don't need duplicates. If we're not snapping to
225 // paths though but only to item nodes then we should still look for the intersections in sp_item_snappoints()
226 bool old_pref = _snapmanager->snapprefs.getSnapIntersectionCS();
227 if (_snapmanager->snapprefs.getSnapToItemPath()) {
228 _snapmanager->snapprefs.setSnapIntersectionCS(false);
229 }
231 bool old_pref2 = _snapmanager->snapprefs.getIncludeItemCenter();
232 if ((*i).item == _snapmanager->getRotationCenterSource()) {
233 // don't snap to this item's rotation center
234 _snapmanager->snapprefs.setIncludeItemCenter(false);
235 }
237 sp_item_snappoints(root_item, *_points_to_snap_to, &_snapmanager->snapprefs);
239 // restore the original snap preferences
240 _snapmanager->snapprefs.setSnapIntersectionCS(old_pref);
241 _snapmanager->snapprefs.setIncludeItemCenter(old_pref2);
242 }
244 //Collect the bounding box's corners so we can snap to them
245 if (p_is_a_bbox || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_bbox) || p_is_other) {
246 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
247 // of the item AND the bbox of the clipping path at the same time
248 if (!(*i).clip_or_mask) {
249 Geom::OptRect b = sp_item_bbox_desktop(root_item, bbox_type);
250 getBBoxPoints(b, _points_to_snap_to, true, _snapmanager->snapprefs.getSnapToBBoxNode(), _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints(), _snapmanager->snapprefs.getSnapBBoxMidpoints());
251 }
252 }
253 }
254 }
255 }
257 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
258 Inkscape::SnapCandidatePoint const &p,
259 std::vector<SnapCandidatePoint> *unselected_nodes) const
260 {
261 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
263 _collectNodes(p.getSourceType(), p.getSourceNum() == 0);
265 if (unselected_nodes != NULL) {
266 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
267 }
269 SnappedPoint s;
270 bool success = false;
272 for (std::vector<SnapCandidatePoint>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
273 Geom::Coord dist = Geom::L2((*k).getPoint() - p.getPoint());
274 if (dist < getSnapperTolerance() && dist < s.getSnapDistance()) {
275 s = SnappedPoint((*k).getPoint(), p.getSourceType(), p.getSourceNum(), (*k).getTargetType(), dist, getSnapperTolerance(), getSnapperAlwaysSnap(), false, true, (*k).getTargetBBox());
276 success = true;
277 }
278 }
280 if (success) {
281 sc.points.push_back(s);
282 }
283 }
285 void Inkscape::ObjectSnapper::_snapTranslatingGuide(SnappedConstraints &sc,
286 Geom::Point const &p,
287 Geom::Point const &guide_normal) const
288 {
289 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
290 _collectNodes(SNAPSOURCE_GUIDE, true);
292 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
293 _collectPaths(Inkscape::SnapCandidatePoint(p, SNAPSOURCE_GUIDE), true);
294 _snapPaths(sc, Inkscape::SnapCandidatePoint(p, SNAPSOURCE_GUIDE), NULL, NULL);
295 }
297 SnappedPoint s;
299 Geom::Coord tol = getSnapperTolerance();
301 for (std::vector<SnapCandidatePoint>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
303 // Project each node (*k) on the guide line (running through point p)
304 Geom::Point p_proj = Geom::projection((*k).getPoint(), Geom::Line(p, p + Geom::rot90(guide_normal)));
305 Geom::Coord dist = Geom::L2((*k).getPoint() - p_proj); // distance from node to the guide
306 Geom::Coord dist2 = Geom::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
307 if ((dist < tol && dist2 < tol) || getSnapperAlwaysSnap()) {
308 s = SnappedPoint((*k).getPoint(), SNAPSOURCE_GUIDE, 0, (*k).getTargetType(), dist, tol, getSnapperAlwaysSnap(), false, true, (*k).getTargetBBox());
309 sc.points.push_back(s);
310 }
311 }
312 }
315 /**
316 * Returns index of first NR_END bpath in array.
317 */
319 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::SnapCandidatePoint const &p,
320 bool const &first_point) const
321 {
322 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
323 // e.g. when translating an item using the selector tool, then we will only do this for the
324 // first point and store the collection for later use. This significantly improves the performance
325 if (first_point) {
326 _clear_paths();
328 // Determine the type of bounding box we should snap to
329 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
331 bool p_is_a_node = p.getSourceType() & Inkscape::SNAPSOURCE_NODE_CATEGORY;
332 bool p_is_other = p.getSourceType() & Inkscape::SNAPSOURCE_OTHER_CATEGORY;
334 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
335 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
336 int prefs_bbox = prefs->getBool("/tools/bounding_box", 0);
337 bbox_type = !prefs_bbox ?
338 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
339 }
341 // Consider the page border for snapping
342 if (_snapmanager->snapprefs.getSnapToPageBorder() && _snapmanager->snapprefs.getSnapModeBBoxOrNodes()) {
343 Geom::PathVector *border_path = _getBorderPathv();
344 if (border_path != NULL) {
345 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(border_path, SNAPTARGET_PAGE_BORDER, Geom::OptRect()));
346 }
347 }
349 for (std::vector<SnapCandidateItem>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
351 /* Transform the requested snap point to this item's coordinates */
352 Geom::Matrix i2doc(Geom::identity());
353 SPItem *root_item = NULL;
354 /* We might have a clone at hand, so make sure we get the root item */
355 if (SP_IS_USE((*i).item)) {
356 i2doc = sp_use_get_root_transform(SP_USE((*i).item));
357 root_item = sp_use_root(SP_USE((*i).item));
358 g_return_if_fail(root_item);
359 } else {
360 i2doc = sp_item_i2doc_affine((*i).item);
361 root_item = (*i).item;
362 }
364 //Build a list of all paths considered for snapping to
366 //Add the item's path to snap to
367 if (_snapmanager->snapprefs.getSnapToItemPath() && _snapmanager->snapprefs.getSnapModeNode()) {
368 if (p_is_other || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node)) {
369 // Snapping to the path of characters is very cool, but for a large
370 // chunk of text this will take ages! So limit snapping to text paths
371 // containing max. 240 characters. Snapping the bbox will not be affected
372 bool very_lenghty_prose = false;
373 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
374 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
375 }
376 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
377 // which corresponds to a lag of 500 msec. This is for snapping a rect
378 // to a single line of text.
380 // Snapping for example to a traced bitmap is also very stressing for
381 // the CPU, so we'll only snap to paths having no more than 500 nodes
382 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
383 bool very_complex_path = false;
384 if (SP_IS_PATH(root_item)) {
385 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
386 }
388 if (!very_lenghty_prose && !very_complex_path) {
389 SPCurve *curve = curve_for_item(root_item);
390 if (curve) {
391 // We will get our own copy of the pathvector, which must be freed at some point
393 // Geom::PathVector *pv = pathvector_for_curve(root_item, curve, true, true, Geom::identity(), (*i).additional_affine);
395 Geom::PathVector *pv = new Geom::PathVector(curve->get_pathvector());
396 (*pv) *= sp_item_i2d_affine(root_item) * (*i).additional_affine * _snapmanager->getDesktop()->doc2dt(); // (_edit_transform * _i2d_transform);
398 _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.
399 curve->unref();
400 }
401 }
402 }
403 }
405 //Add the item's bounding box to snap to
406 if (_snapmanager->snapprefs.getSnapToBBoxPath() && _snapmanager->snapprefs.getSnapModeBBox()) {
407 if (p_is_other || !(_snapmanager->snapprefs.getStrictSnapping() && p_is_a_node)) {
408 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
409 // of the item AND the bbox of the clipping path at the same time
410 if (!(*i).clip_or_mask) {
411 Geom::OptRect rect;
412 sp_item_invoke_bbox(root_item, rect, i2doc, TRUE, bbox_type);
413 if (rect) {
414 Geom::PathVector *path = _getPathvFromRect(*rect);
415 rect = sp_item_bbox_desktop(root_item, bbox_type);
416 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(path, SNAPTARGET_BBOX_EDGE, rect));
417 }
418 }
419 }
420 }
421 }
422 }
423 }
425 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
426 Inkscape::SnapCandidatePoint const &p,
427 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
428 SPPath const *selected_path) const
429 {
430 _collectPaths(p, p.getSourceNum() == 0);
431 // Now we can finally do the real snapping, using the paths collected above
433 g_assert(_snapmanager->getDesktop() != NULL);
434 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p.getPoint());
436 bool const node_tool_active = _snapmanager->snapprefs.getSnapToItemPath() && selected_path != NULL;
438 if (p.getSourceNum() == 0) {
439 /* findCandidates() is used for snapping to both paths and nodes. It ignores the path that is
440 * currently being edited, because that path requires special care: when snapping to nodes
441 * only the unselected nodes of that path should be considered, and these will be passed on separately.
442 * This path must not be ignored however when snapping to the paths, so we add it here
443 * manually when applicable.
444 * */
445 if (node_tool_active) {
446 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
447 if (curve) {
448 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
449 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(pathv, SNAPTARGET_PATH, Geom::OptRect(), true));
450 curve->unref();
451 }
452 }
453 }
455 int num_path = 0;
456 int num_segm = 0;
458 for (std::vector<Inkscape::SnapCandidatePath >::const_iterator it_p = _paths_to_snap_to->begin(); it_p != _paths_to_snap_to->end(); it_p++) {
459 bool const being_edited = node_tool_active && (*it_p).currently_being_edited;
460 //if true then this pathvector it_pv is currently being edited in the node tool
462 for(Geom::PathVector::iterator it_pv = (it_p->path_vector)->begin(); it_pv != (it_p->path_vector)->end(); ++it_pv) {
463 // Find a nearest point for each curve within this path
464 // n curves will return n time values with 0 <= t <= 1
465 std::vector<double> anp = (*it_pv).nearestPointPerCurve(p_doc);
467 std::vector<double>::const_iterator np = anp.begin();
468 unsigned int index = 0;
469 for (; np != anp.end(); np++, index++) {
470 Geom::Curve const *curve = &((*it_pv).at_index(index));
471 Geom::Point const sp_doc = curve->pointAt(*np);
473 bool c1 = true;
474 bool c2 = true;
475 if (being_edited) {
476 /* If the path is being edited, then we should only snap though to stationary pieces of the path
477 * and not to the pieces that are being dragged around. This way we avoid
478 * self-snapping. For this we check whether the nodes at both ends of the current
479 * piece are unselected; if they are then this piece must be stationary
480 */
481 g_assert(unselected_nodes != NULL);
482 Geom::Point start_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(0));
483 Geom::Point end_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(1));
484 c1 = isUnselectedNode(start_pt, unselected_nodes);
485 c2 = isUnselectedNode(end_pt, unselected_nodes);
486 /* Unfortunately, this might yield false positives for coincident nodes. Inkscape might therefore mistakenly
487 * snap to path segments that are not stationary. There are at least two possible ways to overcome this:
488 * - Linking the individual nodes of the SPPath we have here, to the nodes of the NodePath::SubPath class as being
489 * used in sp_nodepath_selected_nodes_move. This class has a member variable called "selected". For this the nodes
490 * should be in the exact same order for both classes, so we can index them
491 * - Replacing the SPPath being used here by the the NodePath::SubPath class; but how?
492 */
493 }
495 Geom::Point const sp_dt = _snapmanager->getDesktop()->doc2dt(sp_doc);
496 if (!being_edited || (c1 && c2)) {
497 Geom::Coord const dist = Geom::distance(sp_doc, p_doc);
498 if (dist < getSnapperTolerance()) {
499 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));
500 }
501 }
502 }
503 num_segm++;
504 } // End of: for (Geom::PathVector::iterator ....)
505 num_path++;
506 }
507 }
509 /* Returns true if point is coincident with one of the unselected nodes */
510 bool Inkscape::ObjectSnapper::isUnselectedNode(Geom::Point const &point, std::vector<Inkscape::SnapCandidatePoint> const *unselected_nodes) const
511 {
512 if (unselected_nodes == NULL) {
513 return false;
514 }
516 if (unselected_nodes->size() == 0) {
517 return false;
518 }
520 for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
521 if (Geom::L2(point - (*i).getPoint()) < 1e-4) {
522 return true;
523 }
524 }
526 return false;
527 }
529 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
530 Inkscape::SnapCandidatePoint const &p,
531 SnapConstraint const &c) const
532 {
534 _collectPaths(p, p.getSourceNum() == 0);
536 // Now we can finally do the real snapping, using the paths collected above
538 g_assert(_snapmanager->getDesktop() != NULL);
539 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p.getPoint());
541 Geom::Point direction_vector = c.getDirection();
542 if (!is_zero(direction_vector)) {
543 direction_vector = Geom::unit_vector(direction_vector);
544 }
546 // The intersection point of the constraint line with any path, must lie within two points on the
547 // SnapConstraint: p_min_on_cl and p_max_on_cl. The distance between those points is twice the snapping tolerance
548 Geom::Point const p_proj_on_cl = p.getPoint(); // projection has already been taken care of in constrainedSnap in the snapmanager;
549 Geom::Point const p_min_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
550 Geom::Point const p_max_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
551 Geom::Coord tolerance = getSnapperTolerance();
553 // PS: Because the paths we're about to snap to are all expressed relative to document coordinate system, we will have
554 // to convert the snapper coordinates from the desktop coordinates to document coordinates
556 std::vector<Geom::Path> constraint_path;
557 if (c.isCircular()) {
558 Geom::Circle constraint_circle(_snapmanager->getDesktop()->dt2doc(c.getPoint()), c.getRadius());
559 constraint_circle.getPath(constraint_path);
560 } else {
561 Geom::Path constraint_line;
562 constraint_line.start(p_min_on_cl);
563 constraint_line.appendNew<Geom::LineSegment>(p_max_on_cl);
564 constraint_path.push_back(constraint_line);
565 }
567 for (std::vector<Inkscape::SnapCandidatePath >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
568 if (k->path_vector) {
569 Geom::CrossingSet cs = Geom::crossings(constraint_path, *(k->path_vector));
570 unsigned int index = 0;
571 for (Geom::CrossingSet::const_iterator i = cs.begin(); i != cs.end(); i++) {
572 if (index >= constraint_path.size()) {
573 break;
574 }
575 for (Geom::Crossings::const_iterator m = (*i).begin(); m != (*i).end(); m++) {
576 //std::cout << "ta = " << (*m).ta << " | tb = " << (*m).tb << std::endl;
577 // Reconstruct the point of intersection
578 Geom::Point p_inters = constraint_path[index].pointAt((*m).ta);
579 // .. and convert it to desktop coordinates
580 p_inters = _snapmanager->getDesktop()->doc2dt(p_inters);
581 Geom::Coord dist = Geom::L2(p_proj_on_cl - p_inters);
582 SnappedPoint s = SnappedPoint(p_inters, p.getSourceType(), p.getSourceNum(), k->target_type, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true, k->target_bbox);;
583 if (dist <= tolerance) { // If the intersection is within snapping range, then we might snap to it
584 sc.points.push_back(s);
585 }
586 }
587 index++;
588 }
589 }
590 }
591 }
594 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
595 Inkscape::SnapCandidatePoint const &p,
596 Geom::OptRect const &bbox_to_snap,
597 std::vector<SPItem const *> const *it,
598 std::vector<SnapCandidatePoint> *unselected_nodes) const
599 {
600 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(p.getSourceType()) == false ) {
601 return;
602 }
604 /* Get a list of all the SPItems that we will try to snap to */
605 if (p.getSourceNum() == 0) {
606 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p.getPoint(), p.getPoint());
607 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, p.getSourceNum() == 0, local_bbox_to_snap, false, Geom::identity());
608 }
611 bool snap_nodes = (_snapmanager->snapprefs.getSnapModeNode() && (
612 _snapmanager->snapprefs.getSnapToItemNode() ||
613 _snapmanager->snapprefs.getSnapSmoothNodes() ||
614 _snapmanager->snapprefs.getSnapLineMidpoints() ||
615 _snapmanager->snapprefs.getSnapObjectMidpoints()
616 )) || (_snapmanager->snapprefs.getSnapModeBBox() && (
617 _snapmanager->snapprefs.getSnapToBBoxNode() ||
618 _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() ||
619 _snapmanager->snapprefs.getSnapBBoxMidpoints()
620 )) || (_snapmanager->snapprefs.getSnapModeBBoxOrNodes() && (
621 _snapmanager->snapprefs.getIncludeItemCenter() ||
622 _snapmanager->snapprefs.getSnapToPageBorder()
623 ));
625 if (snap_nodes) {
626 _snapNodes(sc, p, unselected_nodes);
627 }
629 if (_snapmanager->snapprefs.getSnapModeNode() && _snapmanager->snapprefs.getSnapToItemPath() ||
630 _snapmanager->snapprefs.getSnapModeBBox() && _snapmanager->snapprefs.getSnapToBBoxPath() ||
631 _snapmanager->snapprefs.getSnapModeBBoxOrNodes() && _snapmanager->snapprefs.getSnapToPageBorder()) {
632 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
633 if (n > 0) {
634 /* While editing a path in the node tool, findCandidates must ignore that path because
635 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
636 * That path must not be ignored however when snapping to the paths, so we add it here
637 * manually when applicable
638 */
639 SPPath *path = NULL;
640 if (it != NULL) {
641 if (it->size() == 1 && SP_IS_PATH(*it->begin())) {
642 path = SP_PATH(*it->begin());
643 } // else: *it->begin() might be a SPGroup, e.g. when editing a LPE of text that has been converted to a group of paths
644 // as reported in bug #356743. In that case we can just ignore it, i.e. not snap to this item
645 }
646 _snapPaths(sc, p, unselected_nodes, path);
647 } else {
648 _snapPaths(sc, p, NULL, NULL);
649 }
650 }
651 }
653 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
654 Inkscape::SnapCandidatePoint const &p,
655 Geom::OptRect const &bbox_to_snap,
656 SnapConstraint const &c,
657 std::vector<SPItem const *> const *it) const
658 {
659 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(p.getSourceType()) == false) {
660 return;
661 }
663 /* Get a list of all the SPItems that we will try to snap to */
664 if (p.getSourceNum() == 0) {
665 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p.getPoint(), p.getPoint());
666 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, p.getSourceNum() == 0, local_bbox_to_snap, false, Geom::identity());
667 }
669 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
670 // This is useful for example when scaling an object while maintaining a fixed aspect ratio. It's
671 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
673 // When snapping to objects, we either snap to their nodes or their paths. It is however very
674 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
675 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
676 // so we will more or less snap to them anyhow.
678 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
679 _snapPathsConstrained(sc, p, c);
680 }
681 }
684 // This method is used to snap a guide to nodes, while dragging the guide around
685 void Inkscape::ObjectSnapper::guideFreeSnap(SnappedConstraints &sc,
686 Geom::Point const &p,
687 Geom::Point const &guide_normal) const
688 {
689 /* Get a list of all the SPItems that we will try to snap to */
690 std::vector<SPItem*> cand;
691 std::vector<SPItem const *> const it; //just an empty list
693 _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), false, Geom::identity());
694 _snapTranslatingGuide(sc, p, guide_normal);
696 }
698 // This method is used to snap the origin of a guide to nodes/paths, while dragging the origin along the guide
699 void Inkscape::ObjectSnapper::guideConstrainedSnap(SnappedConstraints &sc,
700 Geom::Point const &p,
701 Geom::Point const &guide_normal,
702 SnapConstraint const &/*c*/) const
703 {
704 /* Get a list of all the SPItems that we will try to snap to */
705 std::vector<SPItem*> cand;
706 std::vector<SPItem const *> const it; //just an empty list
708 _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), false, Geom::identity());
709 _snapTranslatingGuide(sc, p, guide_normal);
711 }
713 /**
714 * \return true if this Snapper will snap at least one kind of point.
715 */
716 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
717 {
718 bool snap_to_something = (_snapmanager->snapprefs.getSnapModeNode() && (
719 _snapmanager->snapprefs.getSnapToItemPath() ||
720 _snapmanager->snapprefs.getSnapToItemNode() ||
721 _snapmanager->snapprefs.getSnapSmoothNodes() ||
722 _snapmanager->snapprefs.getSnapLineMidpoints() ||
723 _snapmanager->snapprefs.getSnapObjectMidpoints()
724 )) || (_snapmanager->snapprefs.getSnapModeBBox() && (
725 _snapmanager->snapprefs.getSnapToBBoxPath() ||
726 _snapmanager->snapprefs.getSnapToBBoxNode() ||
727 _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() ||
728 _snapmanager->snapprefs.getSnapBBoxMidpoints()
729 )) || (_snapmanager->snapprefs.getSnapModeBBoxOrNodes() && (
730 _snapmanager->snapprefs.getSnapToPageBorder() ||
731 _snapmanager->snapprefs.getIncludeItemCenter()
732 ));
734 return (_snap_enabled && snap_to_something);
735 }
737 void Inkscape::ObjectSnapper::_clear_paths() const
738 {
739 for (std::vector<Inkscape::SnapCandidatePath >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
740 delete k->path_vector;
741 }
742 _paths_to_snap_to->clear();
743 }
745 Geom::PathVector* Inkscape::ObjectSnapper::_getBorderPathv() const
746 {
747 Geom::Rect const border_rect = Geom::Rect(Geom::Point(0,0), Geom::Point(sp_document_width(_snapmanager->getDocument()),sp_document_height(_snapmanager->getDocument())));
748 return _getPathvFromRect(border_rect);
749 }
751 Geom::PathVector* Inkscape::ObjectSnapper::_getPathvFromRect(Geom::Rect const rect) const
752 {
753 SPCurve const *border_curve = SPCurve::new_from_rect(rect, true);
754 if (border_curve) {
755 Geom::PathVector *dummy = new Geom::PathVector(border_curve->get_pathvector());
756 return dummy;
757 } else {
758 return NULL;
759 }
760 }
762 void Inkscape::ObjectSnapper::_getBorderNodes(std::vector<SnapCandidatePoint> *points) const
763 {
764 Geom::Coord w = sp_document_width(_snapmanager->getDocument());
765 Geom::Coord h = sp_document_height(_snapmanager->getDocument());
766 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(0,0), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
767 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(0,h), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
768 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(w,h), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
769 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(w,0), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
770 }
772 void Inkscape::getBBoxPoints(Geom::OptRect const bbox,
773 std::vector<SnapCandidatePoint> *points,
774 bool const /*isTarget*/,
775 bool const includeCorners,
776 bool const includeLineMidpoints,
777 bool const includeObjectMidpoints)
778 {
779 if (bbox) {
780 // collect the corners of the bounding box
781 for ( unsigned k = 0 ; k < 4 ; k++ ) {
782 if (includeCorners) {
783 points->push_back(Inkscape::SnapCandidatePoint(bbox->corner(k), Inkscape::SNAPSOURCE_BBOX_CORNER, 0, Inkscape::SNAPTARGET_BBOX_CORNER, *bbox));
784 }
785 // optionally, collect the midpoints of the bounding box's edges too
786 if (includeLineMidpoints) {
787 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));
788 }
789 }
790 if (includeObjectMidpoints) {
791 points->push_back(Inkscape::SnapCandidatePoint(bbox->midpoint(), Inkscape::SNAPSOURCE_BBOX_MIDPOINT, 0, Inkscape::SNAPTARGET_BBOX_MIDPOINT, *bbox));
792 }
793 }
794 }
796 /*
797 Local Variables:
798 mode:c++
799 c-file-style:"stroustrup"
800 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
801 indent-tabs-mode:nil
802 fill-column:99
803 End:
804 */
805 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :