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::SnapCandidate::SnapCandidate(SPItem* item, bool clip_or_mask, Geom::Matrix additional_affine)
37 : item(item), clip_or_mask(clip_or_mask), additional_affine(additional_affine)
38 {
39 }
41 Inkscape::SnapCandidate::~SnapCandidate()
42 {
43 }
45 Inkscape::ObjectSnapper::ObjectSnapper(SnapManager *sm, Geom::Coord const d)
46 : Snapper(sm, d)
47 {
48 _candidates = new std::vector<SnapCandidate>;
49 _points_to_snap_to = new std::vector<std::pair<Geom::Point, int> >;
50 _paths_to_snap_to = new std::vector<std::pair<Geom::PathVector*, SnapTargetType> >;
51 }
53 Inkscape::ObjectSnapper::~ObjectSnapper()
54 {
55 _candidates->clear();
56 delete _candidates;
58 _points_to_snap_to->clear();
59 delete _points_to_snap_to;
61 _clear_paths();
62 delete _paths_to_snap_to;
63 }
65 /**
66 * \return Snap tolerance (desktop coordinates); depends on current zoom so that it's always the same in screen pixels
67 */
68 Geom::Coord Inkscape::ObjectSnapper::getSnapperTolerance() const
69 {
70 SPDesktop const *dt = _snapmanager->getDesktop();
71 double const zoom = dt ? dt->current_zoom() : 1;
72 return _snapmanager->snapprefs.getObjectTolerance() / zoom;
73 }
75 bool Inkscape::ObjectSnapper::getSnapperAlwaysSnap() const
76 {
77 return _snapmanager->snapprefs.getObjectTolerance() == 10000; //TODO: Replace this threshold of 10000 by a constant; see also tolerance-slider.cpp
78 }
80 /**
81 * Find all items within snapping range.
82 * \param parent Pointer to the document's root, or to a clipped path or mask object
83 * \param it List of items to ignore
84 * \param first_point If true then this point is the first one from a whole bunch of points
85 * \param bbox_to_snap Bounding box hulling the whole bunch of points, all from the same selection and having the same transformation
86 * \param DimensionToSnap Snap in X, Y, or both directions.
87 */
89 void Inkscape::ObjectSnapper::_findCandidates(SPObject* parent,
90 std::vector<SPItem const *> const *it,
91 bool const &first_point,
92 Geom::Rect const &bbox_to_snap,
93 DimensionToSnap const snap_dim,
94 bool const clip_or_mask,
95 Geom::Matrix const additional_affine) const // transformation of the item being clipped / masked
96 {
97 bool const c1 = (snap_dim == TRANSL_SNAP_XY) && ThisSnapperMightSnap();
98 bool const c2 = (snap_dim != TRANSL_SNAP_XY) && GuidesMightSnap();
100 if (!(c1 || c2)) {
101 return;
102 }
104 if (first_point) {
105 _candidates->clear();
106 }
108 Geom::Rect bbox_to_snap_incl = bbox_to_snap; // _incl means: will include the snapper tolerance
109 bbox_to_snap_incl.expandBy(getSnapperTolerance()); // see?
111 for (SPObject* o = sp_object_first_child(parent); o != NULL; o = SP_OBJECT_NEXT(o)) {
112 g_assert(_snapmanager->getDesktop() != NULL);
113 if (SP_IS_ITEM(o) && !(_snapmanager->getDesktop()->itemIsHidden(SP_ITEM(o)) && !clip_or_mask)) {
114 // Snapping to items in a locked layer is allowed
115 // Don't snap to hidden objects, unless they're a clipped path or a mask
116 /* See if this item is on the ignore list */
117 std::vector<SPItem const *>::const_iterator i;
118 if (it != NULL) {
119 i = it->begin();
120 while (i != it->end() && *i != o) {
121 i++;
122 }
123 }
125 if (it == NULL || i == it->end()) {
126 SPItem *item = SP_ITEM(o);
127 if (item) {
128 SPObject *obj = NULL;
129 if (!clip_or_mask) { // cannot clip or mask more than once
130 // The current item is not a clipping path or a mask, but might
131 // still be the subject of clipping or masking itself ; if so, then
132 // we should also consider that path or mask for snapping to
133 obj = SP_OBJECT(item->clip_ref->getObject());
134 if (obj) {
135 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
136 }
137 obj = SP_OBJECT(item->mask_ref->getObject());
138 if (obj) {
139 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
140 }
141 }
142 }
144 if (SP_IS_GROUP(o)) {
145 _findCandidates(o, it, false, bbox_to_snap, snap_dim, clip_or_mask, additional_affine);
146 } else {
147 Geom::OptRect bbox_of_item = Geom::Rect();
148 if (clip_or_mask) {
149 // Oh oh, this will get ugly. We cannot use sp_item_i2d_affine directly because we need to
150 // insert an additional transformation in document coordinates (code copied from sp_item_i2d_affine)
151 sp_item_invoke_bbox(item,
152 bbox_of_item,
153 sp_item_i2doc_affine(item) * additional_affine * _snapmanager->getDesktop()->doc2dt(),
154 true);
155 } else {
156 sp_item_invoke_bbox(item, bbox_of_item, sp_item_i2d_affine(item), true);
157 }
158 if (bbox_of_item) {
159 // See if the item is within range
160 if (bbox_to_snap_incl.intersects(*bbox_of_item)) {
161 // This item is within snapping range, so record it as a candidate
162 _candidates->push_back(SnapCandidate(item, clip_or_mask, additional_affine));
163 // For debugging: print the id of the candidate to the console
164 // SPObject *obj = (SPObject*)item;
165 // std::cout << "Snap candidate added: " << obj->id << std::endl;
166 }
167 }
168 }
169 }
170 }
171 }
172 }
175 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::SnapPreferences::PointType const &t,
176 bool const &first_point) const
177 {
178 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
179 // e.g. when translating an item using the selector tool, then we will only do this for the
180 // first point and store the collection for later use. This significantly improves the performance
181 if (first_point) {
182 _points_to_snap_to->clear();
184 // Determine the type of bounding box we should snap to
185 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
187 bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
188 bool p_is_a_bbox = t & Inkscape::SnapPreferences::SNAPPOINT_BBOX;
189 bool p_is_a_guide = t & Inkscape::SnapPreferences::SNAPPOINT_GUIDE;
191 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
192 g_assert(!((p_is_a_node && p_is_a_bbox) || (p_is_a_bbox && p_is_a_guide) || (p_is_a_node && p_is_a_guide)));
194 if (_snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()) {
195 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
196 bool prefs_bbox = prefs->getBool("/tools/bounding_box");
197 bbox_type = !prefs_bbox ?
198 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
199 }
201 // Consider the page border for snapping to
202 if (_snapmanager->snapprefs.getSnapToPageBorder()) {
203 _getBorderNodes(_points_to_snap_to);
204 }
206 for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
207 //Geom::Matrix i2doc(Geom::identity());
208 SPItem *root_item = (*i).item;
209 if (SP_IS_USE((*i).item)) {
210 root_item = sp_use_root(SP_USE((*i).item));
211 }
212 g_return_if_fail(root_item);
214 //Collect all nodes so we can snap to them
215 if (p_is_a_node || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node) || p_is_a_guide) {
216 // Note: there are two ways in which intersections are considered:
217 // Method 1: Intersections are calculated for each shape individually, for both the
218 // snap source and snap target (see sp_shape_snappoints)
219 // Method 2: Intersections are calculated for each curve or line that we've snapped to, i.e. only for
220 // the target (see the intersect() method in the SnappedCurve and SnappedLine classes)
221 // Some differences:
222 // - Method 1 doesn't find intersections within a set of multiple objects
223 // - Method 2 only works for targets
224 // When considering intersections as snap targets:
225 // - Method 1 only works when snapping to nodes, whereas
226 // - Method 2 only works when snapping to paths
227 // - There will be performance differences too!
228 // If both methods are being used simultaneously, then this might lead to duplicate targets!
230 // Well, here we will be looking for snap TARGETS. Both methods can therefore be used.
231 // When snapping to paths, we will get a collection of snapped lines and snapped curves. findBestSnap() will
232 // go hunting for intersections (but only when asked to in the prefs of course). In that case we can just
233 // temporarily block the intersections in sp_item_snappoints, we don't need duplicates. If we're not snapping to
234 // paths though but only to item nodes then we should still look for the intersections in sp_item_snappoints()
235 bool old_pref = _snapmanager->snapprefs.getSnapIntersectionCS();
236 if (_snapmanager->snapprefs.getSnapToItemPath()) {
237 _snapmanager->snapprefs.setSnapIntersectionCS(false);
238 }
240 sp_item_snappoints(root_item, true, *_points_to_snap_to, &_snapmanager->snapprefs);
242 if (_snapmanager->snapprefs.getSnapToItemPath()) {
243 _snapmanager->snapprefs.setSnapIntersectionCS(old_pref);
244 }
245 }
247 //Collect the bounding box's corners so we can snap to them
248 if (p_is_a_bbox || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_bbox) || p_is_a_guide) {
249 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
250 // of the item AND the bbox of the clipping path at the same time
251 if (!(*i).clip_or_mask) {
252 Geom::OptRect b = sp_item_bbox_desktop(root_item, bbox_type);
253 getBBoxPoints(b, _points_to_snap_to, true, _snapmanager->snapprefs.getSnapToBBoxNode(), _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints(), _snapmanager->snapprefs.getSnapBBoxMidpoints());
254 }
255 }
256 }
257 }
258 }
260 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
261 Inkscape::SnapPreferences::PointType const &t,
262 Geom::Point const &p,
263 SnapSourceType const &source_type,
264 bool const &first_point,
265 std::vector<std::pair<Geom::Point, int> > *unselected_nodes) const
266 {
267 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
269 _collectNodes(t, first_point);
271 if (unselected_nodes != NULL) {
272 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
273 }
275 SnappedPoint s;
276 bool success = false;
278 for (std::vector<std::pair<Geom::Point, int> >::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
279 Geom::Coord dist = Geom::L2((*k).first - p);
280 if (dist < getSnapperTolerance() && dist < s.getSnapDistance()) {
281 s = SnappedPoint((*k).first, source_type, static_cast<Inkscape::SnapTargetType>((*k).second), dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
282 success = true;
283 }
284 }
286 if (success) {
287 sc.points.push_back(s);
288 }
289 }
291 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
292 Inkscape::SnapPreferences::PointType const &t,
293 Geom::Point const &p,
294 Geom::Point const &guide_normal) const
295 {
296 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
297 _collectNodes(t, true);
299 SnappedPoint s;
301 Geom::Coord tol = getSnapperTolerance();
303 for (std::vector<std::pair<Geom::Point, int> >::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
304 // Project each node (*k) on the guide line (running through point p)
305 Geom::Point p_proj = Geom::projection((*k).first, Geom::Line(p, p + Geom::rot90(guide_normal)));
306 Geom::Coord dist = Geom::L2((*k).first - p_proj); // distance from node to the guide
307 Geom::Coord dist2 = Geom::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
308 if ((dist < tol && dist2 < tol) || getSnapperAlwaysSnap()) {
309 s = SnappedPoint((*k).first, SNAPSOURCE_GUIDE, static_cast<Inkscape::SnapTargetType>((*k).second), dist, tol, getSnapperAlwaysSnap(), true);
310 sc.points.push_back(s);
311 }
312 }
313 }
316 /**
317 * Returns index of first NR_END bpath in array.
318 */
320 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::SnapPreferences::PointType const &t,
321 bool const &first_point) const
322 {
323 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
324 // e.g. when translating an item using the selector tool, then we will only do this for the
325 // first point and store the collection for later use. This significantly improves the performance
326 if (first_point) {
327 _clear_paths();
329 // Determine the type of bounding box we should snap to
330 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
332 bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
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()) {
343 Geom::PathVector *border_path = _getBorderPathv();
344 if (border_path != NULL) {
345 _paths_to_snap_to->push_back(std::make_pair(border_path, SNAPTARGET_PAGE_BORDER));
346 }
347 }
349 for (std::vector<SnapCandidate>::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()) {
368 if (!(_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 path, which must be freed at some point
392 Geom::PathVector *borderpathv = pathvector_for_curve(root_item, curve, true, true, Geom::identity(), (*i).additional_affine);
393 _paths_to_snap_to->push_back(std::make_pair(borderpathv, SNAPTARGET_PATH)); // Perhaps for speed, get a reference to the Geom::pathvector, and store the transformation besides it.
394 curve->unref();
395 }
396 }
397 }
398 }
400 //Add the item's bounding box to snap to
401 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
402 if (!(_snapmanager->snapprefs.getStrictSnapping() && p_is_a_node)) {
403 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
404 // of the item AND the bbox of the clipping path at the same time
405 if (!(*i).clip_or_mask) {
406 Geom::OptRect rect;
407 sp_item_invoke_bbox(root_item, rect, i2doc, TRUE, bbox_type);
408 if (rect) {
409 Geom::PathVector *path = _getPathvFromRect(*rect);
410 _paths_to_snap_to->push_back(std::make_pair(path, SNAPTARGET_BBOX_EDGE));
411 }
412 }
413 }
414 }
415 }
416 }
417 }
419 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
420 Inkscape::SnapPreferences::PointType const &t,
421 Geom::Point const &p,
422 SnapSourceType const &source_type,
423 bool const &first_point,
424 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
425 SPPath const *selected_path) const
426 {
427 _collectPaths(t, first_point);
428 // Now we can finally do the real snapping, using the paths collected above
430 g_assert(_snapmanager->getDesktop() != NULL);
431 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p);
433 bool const node_tool_active = _snapmanager->snapprefs.getSnapToItemPath() && selected_path != NULL;
435 if (first_point) {
436 /* findCandidates() is used for snapping to both paths and nodes. It ignores the path that is
437 * currently being edited, because that path requires special care: when snapping to nodes
438 * only the unselected nodes of that path should be considered, and these will be passed on separately.
439 * This path must not be ignored however when snapping to the paths, so we add it here
440 * manually when applicable.
441 *
442 * Note that this path must be the last in line!
443 * */
444 if (node_tool_active) {
445 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
446 if (curve) {
447 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
448 _paths_to_snap_to->push_back(std::make_pair(pathv, SNAPTARGET_PATH));
449 curve->unref();
450 }
451 }
452 }
454 for (std::vector<std::pair<Geom::PathVector*, SnapTargetType> >::const_iterator it_p = _paths_to_snap_to->begin(); it_p != _paths_to_snap_to->end(); it_p++) {
455 bool const being_edited = (node_tool_active && (*it_p) == _paths_to_snap_to->back());
456 //if true then this pathvector it_pv is currently being edited in the node tool
458 // char * svgd = sp_svg_write_path(**it_p->first);
459 // std::cout << "Dumping the pathvector: " << svgd << std::endl;
461 for(Geom::PathVector::iterator it_pv = (it_p->first)->begin(); it_pv != (it_p->first)->end(); ++it_pv) {
462 // Find a nearest point for each curve within this path
463 // n curves will return n time values with 0 <= t <= 1
464 std::vector<double> anp = (*it_pv).nearestPointPerCurve(p_doc);
466 std::vector<double>::const_iterator np = anp.begin();
467 unsigned int index = 0;
468 for (; np != anp.end(); np++, index++) {
469 Geom::Curve const *curve = &((*it_pv).at_index(index));
470 Geom::Point const sp_doc = curve->pointAt(*np);
472 bool c1 = true;
473 bool c2 = true;
474 if (being_edited) {
475 /* If the path is being edited, then we should only snap though to stationary pieces of the path
476 * and not to the pieces that are being dragged around. This way we avoid
477 * self-snapping. For this we check whether the nodes at both ends of the current
478 * piece are unselected; if they are then this piece must be stationary
479 */
480 g_assert(unselected_nodes != NULL);
481 Geom::Point start_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(0));
482 Geom::Point end_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(1));
483 c1 = isUnselectedNode(start_pt, unselected_nodes);
484 c2 = isUnselectedNode(end_pt, unselected_nodes);
485 /* Unfortunately, this might yield false positives for coincident nodes. Inkscape might therefore mistakenly
486 * snap to path segments that are not stationary. There are at least two possible ways to overcome this:
487 * - Linking the individual nodes of the SPPath we have here, to the nodes of the NodePath::SubPath class as being
488 * used in sp_nodepath_selected_nodes_move. This class has a member variable called "selected". For this the nodes
489 * should be in the exact same order for both classes, so we can index them
490 * - Replacing the SPPath being used here by the the NodePath::SubPath class; but how?
491 */
492 }
494 Geom::Point const sp_dt = _snapmanager->getDesktop()->doc2dt(sp_doc);
495 if (!being_edited || (c1 && c2)) {
496 Geom::Coord const dist = Geom::distance(sp_doc, p_doc);
497 if (dist < getSnapperTolerance()) {
498 sc.curves.push_back(Inkscape::SnappedCurve(sp_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), false, curve, source_type, it_p->second));
499 }
500 }
501 }
502 } // End of: for (Geom::PathVector::iterator ....)
503 }
504 }
506 /* Returns true if point is coincident with one of the unselected nodes */
507 bool Inkscape::ObjectSnapper::isUnselectedNode(Geom::Point const &point, std::vector<std::pair<Geom::Point, int> > const *unselected_nodes) const
508 {
509 if (unselected_nodes == NULL) {
510 return false;
511 }
513 if (unselected_nodes->size() == 0) {
514 return false;
515 }
517 for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
518 if (Geom::L2(point - (*i).first) < 1e-4) {
519 return true;
520 }
521 }
523 return false;
524 }
526 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
527 Inkscape::SnapPreferences::PointType const &t,
528 Geom::Point const &p,
529 SnapSourceType const source_type,
530 bool const &first_point,
531 ConstraintLine const &c) const
532 {
534 _collectPaths(t, first_point);
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);
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,
547 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
548 // The distance between those points is twice the snapping tolerance
549 Geom::Point const p_proj_on_cl = c.projection(p);
550 Geom::Point const p_min_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
551 Geom::Point const p_max_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
553 Geom::Path cl;
554 std::vector<Geom::Path> clv;
555 cl.start(p_min_on_cl);
556 cl.appendNew<Geom::LineSegment>(p_max_on_cl);
557 clv.push_back(cl);
559 for (std::vector<std::pair<Geom::PathVector*, SnapTargetType> >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
560 if (k->first) {
561 Geom::CrossingSet cs = Geom::crossings(clv, *(k->first));
562 if (cs.size() > 0) {
563 // We need only the first element of cs, because cl is only a single straight linesegment
564 // This first element contains a vector filled with crossings of cl with k->first
565 for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
566 if ((*m).ta >= 0 && (*m).ta <= 1 ) {
567 // Reconstruct the point of intersection
568 Geom::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
569 // When it's within snapping range, then return it
570 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
571 Geom::Coord dist = Geom::L2(_snapmanager->getDesktop()->dt2doc(p_proj_on_cl) - p_inters);
572 SnappedPoint s(_snapmanager->getDesktop()->doc2dt(p_inters), source_type, k->second, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
573 sc.points.push_back(s);
574 }
575 }
576 }
577 }
578 }
579 }
582 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
583 Inkscape::SnapPreferences::PointType const &t,
584 Geom::Point const &p,
585 SnapSourceType const &source_type,
586 bool const &first_point,
587 Geom::OptRect const &bbox_to_snap,
588 std::vector<SPItem const *> const *it,
589 std::vector<std::pair<Geom::Point, int> > *unselected_nodes) const
590 {
591 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false ) {
592 return;
593 }
595 /* Get a list of all the SPItems that we will try to snap to */
596 if (first_point) {
597 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
598 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
599 }
601 if (_snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapSmoothNodes()
602 || _snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapToPageBorder()
603 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
604 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
605 || _snapmanager->snapprefs.getIncludeItemCenter()) {
606 _snapNodes(sc, t, p, source_type, first_point, unselected_nodes);
607 }
609 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
610 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
611 if (n > 0) {
612 /* While editing a path in the node tool, findCandidates must ignore that path because
613 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
614 * That path must not be ignored however when snapping to the paths, so we add it here
615 * manually when applicable
616 */
617 SPPath *path = NULL;
618 if (it != NULL) {
619 if (it->size() == 1 && SP_IS_PATH(*it->begin())) {
620 path = SP_PATH(*it->begin());
621 } // else: *it->begin() might be a SPGroup, e.g. when editing a LPE of text that has been converted to a group of paths
622 // as reported in bug #356743. In that case we can just ignore it, i.e. not snap to this item
623 }
624 _snapPaths(sc, t, p, source_type, first_point, unselected_nodes, path);
625 } else {
626 _snapPaths(sc, t, p, source_type, first_point, NULL, NULL);
627 }
628 }
629 }
631 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
632 Inkscape::SnapPreferences::PointType const &t,
633 Geom::Point const &p,
634 SnapSourceType const &source_type,
635 bool const &first_point,
636 Geom::OptRect const &bbox_to_snap,
637 ConstraintLine const &c,
638 std::vector<SPItem const *> const *it) const
639 {
640 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false) {
641 return;
642 }
644 /* Get a list of all the SPItems that we will try to snap to */
645 if (first_point) {
646 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
647 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
648 }
650 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
651 // This is useful for example when scaling an object while maintaining a fixed aspect ratio. It's
652 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
654 // When snapping to objects, we either snap to their nodes or their paths. It is however very
655 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
656 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
657 // so we will more or less snap to them anyhow.
659 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
660 _snapPathsConstrained(sc, t, p, source_type, first_point, c);
661 }
662 }
665 // This method is used to snap a guide to nodes, while dragging the guide around
666 void Inkscape::ObjectSnapper::guideSnap(SnappedConstraints &sc,
667 Geom::Point const &p,
668 Geom::Point const &guide_normal) const
669 {
670 /* Get a list of all the SPItems that we will try to snap to */
671 std::vector<SPItem*> cand;
672 std::vector<SPItem const *> const it; //just an empty list
674 DimensionToSnap snap_dim;
675 if (guide_normal == to_2geom(component_vectors[Geom::Y])) {
676 snap_dim = GUIDE_TRANSL_SNAP_Y;
677 } else if (guide_normal == to_2geom(component_vectors[Geom::X])) {
678 snap_dim = GUIDE_TRANSL_SNAP_X;
679 } else {
680 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
681 }
683 // We don't support ANGLED_GUIDE_ROT_SNAP yet.
685 // It would be cool to allow the user to rotate a guide by dragging it, instead of
686 // only translating it. (For example when CTRL is pressed). We will need an UI part
687 // for that first; and some important usability choices need to be made:
688 // E.g. which point should be used for pivoting? A previously snapped point,
689 // or a transformation center (which can be moved after clicking for the
690 // second time on an object; but should this point then be constrained to the
691 // line, or can it be located anywhere?)
693 _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), snap_dim, false, Geom::identity());
694 _snapTranslatingGuideToNodes(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, guide_normal);
695 // _snapRotatingGuideToNodes has not been implemented yet.
696 }
698 /**
699 * \return true if this Snapper will snap at least one kind of point.
700 */
701 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
702 {
703 bool snap_to_something = _snapmanager->snapprefs.getSnapToItemPath()
704 || _snapmanager->snapprefs.getSnapToItemNode()
705 || _snapmanager->snapprefs.getSnapToBBoxPath()
706 || _snapmanager->snapprefs.getSnapToBBoxNode()
707 || _snapmanager->snapprefs.getSnapToPageBorder()
708 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
709 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
710 || _snapmanager->snapprefs.getIncludeItemCenter();
712 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeBBoxOrNodes() && snap_to_something);
713 }
715 bool Inkscape::ObjectSnapper::GuidesMightSnap() const
716 {
717 bool snap_to_something = _snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapToBBoxNode();
718 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeGuide() && snap_to_something);
719 }
721 void Inkscape::ObjectSnapper::_clear_paths() const
722 {
723 for (std::vector<std::pair<Geom::PathVector*, SnapTargetType> >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
724 g_free(k->first);
725 }
726 _paths_to_snap_to->clear();
727 }
729 Geom::PathVector* Inkscape::ObjectSnapper::_getBorderPathv() const
730 {
731 Geom::Rect const border_rect = Geom::Rect(Geom::Point(0,0), Geom::Point(sp_document_width(_snapmanager->getDocument()),sp_document_height(_snapmanager->getDocument())));
732 return _getPathvFromRect(border_rect);
733 }
735 Geom::PathVector* Inkscape::ObjectSnapper::_getPathvFromRect(Geom::Rect const rect) const
736 {
737 SPCurve const *border_curve = SPCurve::new_from_rect(rect);
738 if (border_curve) {
739 Geom::PathVector *dummy = new Geom::PathVector(border_curve->get_pathvector());
740 return dummy;
741 } else {
742 return NULL;
743 }
744 }
746 void Inkscape::ObjectSnapper::_getBorderNodes(std::vector<std::pair<Geom::Point, int> > *points) const
747 {
748 Geom::Coord w = sp_document_width(_snapmanager->getDocument());
749 Geom::Coord h = sp_document_height(_snapmanager->getDocument());
750 points->push_back(std::make_pair(Geom::Point(0,0), SNAPTARGET_PAGE_CORNER));
751 points->push_back(std::make_pair(Geom::Point(0,h), SNAPTARGET_PAGE_CORNER));
752 points->push_back(std::make_pair(Geom::Point(w,h), SNAPTARGET_PAGE_CORNER));
753 points->push_back(std::make_pair(Geom::Point(w,0), SNAPTARGET_PAGE_CORNER));
754 }
756 void Inkscape::getBBoxPoints(Geom::OptRect const bbox, std::vector<std::pair<Geom::Point, int> > *points, bool const isTarget, bool const includeCorners, bool const includeLineMidpoints, bool const includeObjectMidpoints)
757 {
758 if (bbox) {
759 // collect the corners of the bounding box
760 for ( unsigned k = 0 ; k < 4 ; k++ ) {
761 if (includeCorners) {
762 points->push_back(std::make_pair((bbox->corner(k)), isTarget ? int(Inkscape::SNAPTARGET_BBOX_CORNER) : int(Inkscape::SNAPSOURCE_BBOX_CORNER)));
763 }
764 // optionally, collect the midpoints of the bounding box's edges too
765 if (includeLineMidpoints) {
766 points->push_back(std::make_pair((bbox->corner(k) + bbox->corner((k+1) % 4))/2, isTarget ? int(Inkscape::SNAPTARGET_BBOX_EDGE_MIDPOINT) : int(Inkscape::SNAPSOURCE_BBOX_EDGE_MIDPOINT)));
767 }
768 }
769 if (includeObjectMidpoints) {
770 points->push_back(std::make_pair(bbox->midpoint(), isTarget ? int(Inkscape::SNAPTARGET_BBOX_MIDPOINT) : int(Inkscape::SNAPSOURCE_BBOX_MIDPOINT)));
771 }
772 }
773 }
775 /*
776 Local Variables:
777 mode:c++
778 c-file-style:"stroustrup"
779 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
780 indent-tabs-mode:nil
781 fill-column:99
782 End:
783 */
784 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :