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 "libnr/nr-rect-ops.h"
16 #include "libnr/nr-point-fns.h"
17 #include <2geom/path-intersection.h>
18 #include <2geom/point.h>
19 #include <2geom/rect.h>
20 #include "document.h"
21 #include "sp-namedview.h"
22 #include "sp-image.h"
23 #include "sp-item-group.h"
24 #include "sp-item.h"
25 #include "sp-use.h"
26 #include "display/curve.h"
27 #include "inkscape.h"
28 #include "preferences.h"
29 #include "sp-text.h"
30 #include "sp-flowtext.h"
31 #include "text-editing.h"
32 #include "sp-clippath.h"
33 #include "sp-mask.h"
34 #include "helper/geom-curves.h"
35 #include "desktop.h"
37 Inkscape::SnapCandidate::SnapCandidate(SPItem* item, bool clip_or_mask, Geom::Matrix additional_affine)
38 : item(item), clip_or_mask(clip_or_mask), additional_affine(additional_affine)
39 {
40 }
42 Inkscape::SnapCandidate::~SnapCandidate()
43 {
44 }
46 Inkscape::ObjectSnapper::ObjectSnapper(SnapManager *sm, Geom::Coord const d)
47 : Snapper(sm, d)
48 {
49 _candidates = new std::vector<SnapCandidate>;
50 _points_to_snap_to = new std::vector<std::pair<Geom::Point, int> >;
51 _paths_to_snap_to = new std::vector<std::pair<Geom::PathVector*, SnapTargetType> >;
52 }
54 Inkscape::ObjectSnapper::~ObjectSnapper()
55 {
56 _candidates->clear();
57 delete _candidates;
59 _points_to_snap_to->clear();
60 delete _points_to_snap_to;
62 _clear_paths();
63 delete _paths_to_snap_to;
64 }
66 /**
67 * \return Snap tolerance (desktop coordinates); depends on current zoom so that it's always the same in screen pixels
68 */
69 Geom::Coord Inkscape::ObjectSnapper::getSnapperTolerance() const
70 {
71 SPDesktop const *dt = _snapmanager->getDesktop();
72 double const zoom = dt ? dt->current_zoom() : 1;
73 return _snapmanager->snapprefs.getObjectTolerance() / zoom;
74 }
76 bool Inkscape::ObjectSnapper::getSnapperAlwaysSnap() const
77 {
78 return _snapmanager->snapprefs.getObjectTolerance() == 10000; //TODO: Replace this threshold of 10000 by a constant; see also tolerance-slider.cpp
79 }
81 /**
82 * Find all items within snapping range.
83 * \param parent Pointer to the document's root, or to a clipped path or mask object
84 * \param it List of items to ignore
85 * \param first_point If true then this point is the first one from a whole bunch of points
86 * \param bbox_to_snap Bounding box hulling the whole bunch of points, all from the same selection and having the same transformation
87 * \param DimensionToSnap Snap in X, Y, or both directions.
88 */
90 void Inkscape::ObjectSnapper::_findCandidates(SPObject* parent,
91 std::vector<SPItem const *> const *it,
92 bool const &first_point,
93 Geom::Rect const &bbox_to_snap,
94 DimensionToSnap const snap_dim,
95 bool const clip_or_mask,
96 Geom::Matrix const additional_affine) const // transformation of the item being clipped / masked
97 {
98 bool const c1 = (snap_dim == TRANSL_SNAP_XY) && ThisSnapperMightSnap();
99 bool const c2 = (snap_dim != TRANSL_SNAP_XY) && GuidesMightSnap();
101 if (!(c1 || c2)) {
102 return;
103 }
105 if (first_point) {
106 _candidates->clear();
107 }
109 Geom::Rect bbox_to_snap_incl = bbox_to_snap; // _incl means: will include the snapper tolerance
110 bbox_to_snap_incl.expandBy(getSnapperTolerance()); // see?
112 for (SPObject* o = sp_object_first_child(parent); o != NULL; o = SP_OBJECT_NEXT(o)) {
113 g_assert(_snapmanager->getDesktop() != NULL);
114 if (SP_IS_ITEM(o) && !SP_ITEM(o)->isLocked() && !(_snapmanager->getDesktop()->itemIsHidden(SP_ITEM(o)) && !clip_or_mask)) {
115 // Don't snap to locked items, and
116 // don't snap to hidden objects, unless they're a clipped path or a mask
117 /* See if this item is on the ignore list */
118 std::vector<SPItem const *>::const_iterator i;
119 if (it != NULL) {
120 i = it->begin();
121 while (i != it->end() && *i != o) {
122 i++;
123 }
124 }
126 if (it == NULL || i == it->end()) {
127 SPItem *item = SP_ITEM(o);
128 if (item) {
129 SPObject *obj = NULL;
130 if (!clip_or_mask) { // cannot clip or mask more than once
131 // The current item is not a clipping path or a mask, but might
132 // still be the subject of clipping or masking itself ; if so, then
133 // we should also consider that path or mask for snapping to
134 obj = SP_OBJECT(item->clip_ref->getObject());
135 if (obj) {
136 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
137 }
138 obj = SP_OBJECT(item->mask_ref->getObject());
139 if (obj) {
140 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
141 }
142 }
143 }
145 if (SP_IS_GROUP(o)) {
146 _findCandidates(o, it, false, bbox_to_snap, snap_dim, clip_or_mask, additional_affine);
147 } else {
148 Geom::OptRect bbox_of_item = Geom::Rect();
149 if (clip_or_mask) {
150 // Oh oh, this will get ugly. We cannot use sp_item_i2d_affine directly because we need to
151 // insert an additional transformation in document coordinates (code copied from sp_item_i2d_affine)
152 sp_item_invoke_bbox(item,
153 bbox_of_item,
154 sp_item_i2doc_affine(item) * additional_affine * _snapmanager->getDesktop()->doc2dt(),
155 true);
156 } else {
157 sp_item_invoke_bbox(item, bbox_of_item, sp_item_i2d_affine(item), true);
158 }
159 if (bbox_of_item) {
160 // See if the item is within range
161 if (bbox_to_snap_incl.intersects(*bbox_of_item)) {
162 // This item is within snapping range, so record it as a candidate
163 _candidates->push_back(SnapCandidate(item, clip_or_mask, additional_affine));
164 }
165 }
166 }
167 }
168 }
169 }
170 }
173 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::SnapPreferences::PointType const &t,
174 bool const &first_point) const
175 {
176 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
177 // e.g. when translating an item using the selector tool, then we will only do this for the
178 // first point and store the collection for later use. This significantly improves the performance
179 if (first_point) {
180 _points_to_snap_to->clear();
182 // Determine the type of bounding box we should snap to
183 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
185 bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
186 bool p_is_a_bbox = t & Inkscape::SnapPreferences::SNAPPOINT_BBOX;
187 bool p_is_a_guide = t & Inkscape::SnapPreferences::SNAPPOINT_GUIDE;
189 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
190 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)));
192 if (_snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()) {
193 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
194 bool prefs_bbox = prefs->getBool("/tools/bounding_box");
195 bbox_type = !prefs_bbox ?
196 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
197 }
199 // Consider the page border for snapping to
200 if (_snapmanager->snapprefs.getSnapToPageBorder()) {
201 _getBorderNodes(_points_to_snap_to);
202 }
204 for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
205 //Geom::Matrix i2doc(Geom::identity());
206 SPItem *root_item = (*i).item;
207 if (SP_IS_USE((*i).item)) {
208 root_item = sp_use_root(SP_USE((*i).item));
209 }
210 g_return_if_fail(root_item);
212 //Collect all nodes so we can snap to them
213 if (p_is_a_node || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node) || p_is_a_guide) {
214 // Note: there are two ways in which intersections are considered:
215 // Method 1: Intersections are calculated for each shape individually, for both the
216 // snap source and snap target (see sp_shape_snappoints)
217 // Method 2: Intersections are calculated for each curve or line that we've snapped to, i.e. only for
218 // the target (see the intersect() method in the SnappedCurve and SnappedLine classes)
219 // Some differences:
220 // - Method 1 doesn't find intersections within a set of multiple objects
221 // - Method 2 only works for targets
222 // When considering intersections as snap targets:
223 // - Method 1 only works when snapping to nodes, whereas
224 // - Method 2 only works when snapping to paths
225 // - There will be performance differences too!
226 // If both methods are being used simultaneously, then this might lead to duplicate targets!
228 // Well, here we will be looking for snap TARGETS. Both methods can therefore be used.
229 // When snapping to paths, we will get a collection of snapped lines and snapped curves. findBestSnap() will
230 // go hunting for intersections (but only when asked to in the prefs of course). In that case we can just
231 // temporarily block the intersections in sp_item_snappoints, we don't need duplicates. If we're not snapping to
232 // paths though but only to item nodes then we should still look for the intersections in sp_item_snappoints()
233 bool old_pref = _snapmanager->snapprefs.getSnapIntersectionCS();
234 if (_snapmanager->snapprefs.getSnapToItemPath()) {
235 _snapmanager->snapprefs.setSnapIntersectionCS(false);
236 }
238 sp_item_snappoints(root_item, true, *_points_to_snap_to, &_snapmanager->snapprefs);
240 if (_snapmanager->snapprefs.getSnapToItemPath()) {
241 _snapmanager->snapprefs.setSnapIntersectionCS(old_pref);
242 }
243 }
245 //Collect the bounding box's corners so we can snap to them
246 if (p_is_a_bbox || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_bbox) || p_is_a_guide) {
247 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
248 // of the item AND the bbox of the clipping path at the same time
249 if (!(*i).clip_or_mask) {
250 Geom::OptRect b = sp_item_bbox_desktop(root_item, bbox_type);
251 getBBoxPoints(b, _points_to_snap_to, true, _snapmanager->snapprefs.getSnapToBBoxNode(), _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints(), _snapmanager->snapprefs.getSnapBBoxMidpoints());
252 }
253 }
254 }
255 }
256 }
258 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
259 Inkscape::SnapPreferences::PointType const &t,
260 Geom::Point const &p,
261 SnapSourceType const &source_type,
262 bool const &first_point,
263 std::vector<std::pair<Geom::Point, int> > *unselected_nodes) const
264 {
265 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
267 _collectNodes(t, first_point);
269 if (unselected_nodes != NULL) {
270 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
271 }
273 SnappedPoint s;
274 bool success = false;
276 for (std::vector<std::pair<Geom::Point, int> >::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
277 Geom::Coord dist = Geom::L2((*k).first - p);
278 if (dist < getSnapperTolerance() && dist < s.getSnapDistance()) {
279 s = SnappedPoint((*k).first, source_type, static_cast<Inkscape::SnapTargetType>((*k).second), dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
280 success = true;
281 }
282 }
284 if (success) {
285 sc.points.push_back(s);
286 }
287 }
289 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
290 Inkscape::SnapPreferences::PointType const &t,
291 Geom::Point const &p,
292 Geom::Point const &guide_normal) const
293 {
294 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
295 _collectNodes(t, true);
297 SnappedPoint s;
298 bool success = false;
300 Geom::Coord tol = getSnapperTolerance();
302 for (std::vector<std::pair<Geom::Point, int> >::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 = project_on_linesegment((*k).first, p, p + Geom::rot90(guide_normal));
305 Geom::Coord dist = Geom::L2((*k).first - 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() && dist < s.getSnapDistance())) {
308 s = SnappedPoint((*k).first, SNAPSOURCE_GUIDE, static_cast<Inkscape::SnapTargetType>((*k).second), dist, tol, getSnapperAlwaysSnap(), true);
309 success = true;
310 }
311 }
313 if (success) {
314 sc.points.push_back(s);
315 }
316 }
319 /**
320 * Returns index of first NR_END bpath in array.
321 */
323 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::SnapPreferences::PointType const &t,
324 bool const &first_point) const
325 {
326 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
327 // e.g. when translating an item using the selector tool, then we will only do this for the
328 // first point and store the collection for later use. This significantly improves the performance
329 if (first_point) {
330 _clear_paths();
332 // Determine the type of bounding box we should snap to
333 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
335 bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
337 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
338 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
339 int prefs_bbox = prefs->getBool("/tools/bounding_box", 0);
340 bbox_type = !prefs_bbox ?
341 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
342 }
344 // Consider the page border for snapping
345 if (_snapmanager->snapprefs.getSnapToPageBorder()) {
346 Geom::PathVector *border_path = _getBorderPathv();
347 if (border_path != NULL) {
348 _paths_to_snap_to->push_back(std::make_pair(border_path, SNAPTARGET_PAGE_BORDER));
349 }
350 }
352 for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
354 /* Transform the requested snap point to this item's coordinates */
355 Geom::Matrix i2doc(Geom::identity());
356 SPItem *root_item = NULL;
357 /* We might have a clone at hand, so make sure we get the root item */
358 if (SP_IS_USE((*i).item)) {
359 i2doc = sp_use_get_root_transform(SP_USE((*i).item));
360 root_item = sp_use_root(SP_USE((*i).item));
361 g_return_if_fail(root_item);
362 } else {
363 i2doc = sp_item_i2doc_affine((*i).item);
364 root_item = (*i).item;
365 }
367 //Build a list of all paths considered for snapping to
369 //Add the item's path to snap to
370 if (_snapmanager->snapprefs.getSnapToItemPath()) {
371 if (!(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node)) {
372 // Snapping to the path of characters is very cool, but for a large
373 // chunk of text this will take ages! So limit snapping to text paths
374 // containing max. 240 characters. Snapping the bbox will not be affected
375 bool very_lenghty_prose = false;
376 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
377 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
378 }
379 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
380 // which corresponds to a lag of 500 msec. This is for snapping a rect
381 // to a single line of text.
383 // Snapping for example to a traced bitmap is also very stressing for
384 // the CPU, so we'll only snap to paths having no more than 500 nodes
385 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
386 bool very_complex_path = false;
387 if (SP_IS_PATH(root_item)) {
388 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
389 }
391 if (!very_lenghty_prose && !very_complex_path) {
392 SPCurve *curve = curve_for_item(root_item);
393 if (curve) {
394 // We will get our own copy of the path, which must be freed at some point
395 Geom::PathVector *borderpathv = pathvector_for_curve(root_item, curve, true, true, Geom::identity(), (*i).additional_affine);
396 _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.
397 curve->unref();
398 }
399 }
400 }
401 }
403 //Add the item's bounding box to snap to
404 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
405 if (!(_snapmanager->snapprefs.getStrictSnapping() && p_is_a_node)) {
406 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
407 // of the item AND the bbox of the clipping path at the same time
408 if (!(*i).clip_or_mask) {
409 Geom::OptRect rect;
410 sp_item_invoke_bbox(root_item, rect, i2doc, TRUE, bbox_type);
411 if (rect) {
412 Geom::PathVector *path = _getPathvFromRect(*rect);
413 _paths_to_snap_to->push_back(std::make_pair(path, SNAPTARGET_BBOX_EDGE));
414 }
415 }
416 }
417 }
418 }
419 }
420 }
422 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
423 Inkscape::SnapPreferences::PointType const &t,
424 Geom::Point const &p,
425 SnapSourceType const &source_type,
426 bool const &first_point,
427 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
428 SPPath const *selected_path) const
429 {
430 _collectPaths(t, first_point);
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);
436 bool const node_tool_active = _snapmanager->snapprefs.getSnapToItemPath() && selected_path != NULL;
438 if (first_point) {
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 * Note that this path must be the last in line!
446 * */
447 if (node_tool_active) {
448 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
449 if (curve) {
450 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
451 _paths_to_snap_to->push_back(std::make_pair(pathv, SNAPTARGET_PATH));
452 curve->unref();
453 }
454 }
455 }
457 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++) {
458 bool const being_edited = (node_tool_active && (*it_p) == _paths_to_snap_to->back());
459 //if true then this pathvector it_pv is currently being edited in the node tool
461 // char * svgd = sp_svg_write_path(**it_p->first);
462 // std::cout << "Dumping the pathvector: " << svgd << std::endl;
464 for(Geom::PathVector::iterator it_pv = (it_p->first)->begin(); it_pv != (it_p->first)->end(); ++it_pv) {
465 // Find a nearest point for each curve within this path
466 // n curves will return n time values with 0 <= t <= 1
467 std::vector<double> anp = (*it_pv).nearestPointPerCurve(p_doc);
469 std::vector<double>::const_iterator np = anp.begin();
470 unsigned int index = 0;
471 for (; np != anp.end(); np++, index++) {
472 Geom::Curve const *curve = &((*it_pv).at_index(index));
473 Geom::Point const sp_doc = curve->pointAt(*np);
475 bool c1 = true;
476 bool c2 = true;
477 if (being_edited) {
478 /* If the path is being edited, then we should only snap though to stationary pieces of the path
479 * and not to the pieces that are being dragged around. This way we avoid
480 * self-snapping. For this we check whether the nodes at both ends of the current
481 * piece are unselected; if they are then this piece must be stationary
482 */
483 g_assert(unselected_nodes != NULL);
484 Geom::Point start_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(0));
485 Geom::Point end_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(1));
486 c1 = isUnselectedNode(start_pt, unselected_nodes);
487 c2 = isUnselectedNode(end_pt, unselected_nodes);
488 /* Unfortunately, this might yield false positives for coincident nodes. Inkscape might therefore mistakenly
489 * snap to path segments that are not stationary. There are at least two possible ways to overcome this:
490 * - Linking the individual nodes of the SPPath we have here, to the nodes of the NodePath::SubPath class as being
491 * used in sp_nodepath_selected_nodes_move. This class has a member variable called "selected". For this the nodes
492 * should be in the exact same order for both classes, so we can index them
493 * - Replacing the SPPath being used here by the the NodePath::SubPath class; but how?
494 */
495 }
497 Geom::Point const sp_dt = _snapmanager->getDesktop()->doc2dt(sp_doc);
498 if (!being_edited || (c1 && c2)) {
499 Geom::Coord const dist = Geom::distance(sp_doc, p_doc);
500 if (dist < getSnapperTolerance()) {
501 sc.curves.push_back(Inkscape::SnappedCurve(sp_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), false, curve, source_type, it_p->second));
502 }
503 }
504 }
505 } // End of: for (Geom::PathVector::iterator ....)
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<std::pair<Geom::Point, int> > 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<std::pair<Geom::Point, int> >::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
521 if (Geom::L2(point - (*i).first) < 1e-4) {
522 return true;
523 }
524 }
526 return false;
527 }
529 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
530 Inkscape::SnapPreferences::PointType const &t,
531 Geom::Point const &p,
532 SnapSourceType const source_type,
533 bool const &first_point,
534 ConstraintLine const &c) const
535 {
537 _collectPaths(t, first_point);
539 // Now we can finally do the real snapping, using the paths collected above
541 g_assert(_snapmanager->getDesktop() != NULL);
542 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p);
544 Geom::Point direction_vector = c.getDirection();
545 if (!is_zero(direction_vector)) {
546 direction_vector = Geom::unit_vector(direction_vector);
547 }
549 Geom::Point const p1_on_cl = c.hasPoint() ? c.getPoint() : p;
550 Geom::Point const p2_on_cl = p1_on_cl + direction_vector;
552 // The intersection point of the constraint line with any path,
553 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
554 // The distance between those points is twice the snapping tolerance
555 Geom::Point const p_proj_on_cl = project_on_linesegment(p, p1_on_cl, p2_on_cl);
556 Geom::Point const p_min_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
557 Geom::Point const p_max_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
559 Geom::Path cl;
560 std::vector<Geom::Path> clv;
561 cl.start(p_min_on_cl);
562 cl.appendNew<Geom::LineSegment>(p_max_on_cl);
563 clv.push_back(cl);
565 for (std::vector<std::pair<Geom::PathVector*, SnapTargetType> >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
566 if (k->first) {
567 Geom::CrossingSet cs = Geom::crossings(clv, *(k->first));
568 if (cs.size() > 0) {
569 // We need only the first element of cs, because cl is only a single straight linesegment
570 // This first element contains a vector filled with crossings of cl with k->first
571 for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
572 if ((*m).ta >= 0 && (*m).ta <= 1 ) {
573 // Reconstruct the point of intersection
574 Geom::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
575 // When it's within snapping range, then return it
576 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
577 Geom::Coord dist = Geom::L2(_snapmanager->getDesktop()->dt2doc(p_proj_on_cl) - p_inters);
578 SnappedPoint s(_snapmanager->getDesktop()->doc2dt(p_inters), source_type, k->second, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
579 sc.points.push_back(s);
580 }
581 }
582 }
583 }
584 }
585 }
588 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
589 Inkscape::SnapPreferences::PointType const &t,
590 Geom::Point const &p,
591 SnapSourceType const &source_type,
592 bool const &first_point,
593 Geom::OptRect const &bbox_to_snap,
594 std::vector<SPItem const *> const *it,
595 std::vector<std::pair<Geom::Point, int> > *unselected_nodes) const
596 {
597 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false ) {
598 return;
599 }
601 /* Get a list of all the SPItems that we will try to snap to */
602 if (first_point) {
603 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
604 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
605 }
607 if (_snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapSmoothNodes()
608 || _snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapToPageBorder()
609 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
610 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
611 || _snapmanager->snapprefs.getIncludeItemCenter()) {
612 _snapNodes(sc, t, p, source_type, first_point, unselected_nodes);
613 }
615 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
616 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
617 if (n > 0) {
618 /* While editing a path in the node tool, findCandidates must ignore that path because
619 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
620 * That path must not be ignored however when snapping to the paths, so we add it here
621 * manually when applicable
622 */
623 SPPath *path = NULL;
624 if (it != NULL) {
625 g_assert(SP_IS_PATH(*it->begin()));
626 g_assert(it->size() == 1);
627 path = SP_PATH(*it->begin());
628 }
629 _snapPaths(sc, t, p, source_type, first_point, unselected_nodes, path);
630 } else {
631 _snapPaths(sc, t, p, source_type, first_point, NULL, NULL);
632 }
633 }
634 }
636 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
637 Inkscape::SnapPreferences::PointType const &t,
638 Geom::Point const &p,
639 SnapSourceType const &source_type,
640 bool const &first_point,
641 Geom::OptRect const &bbox_to_snap,
642 ConstraintLine const &c,
643 std::vector<SPItem const *> const *it) const
644 {
645 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false) {
646 return;
647 }
649 /* Get a list of all the SPItems that we will try to snap to */
650 if (first_point) {
651 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
652 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
653 }
655 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
656 // This is useful for example when scaling an object while maintaining a fixed aspect ratio. It's
657 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
659 // When snapping to objects, we either snap to their nodes or their paths. It is however very
660 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
661 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
662 // so we will more or less snap to them anyhow.
664 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
665 _snapPathsConstrained(sc, t, p, source_type, first_point, c);
666 }
667 }
670 // This method is used to snap a guide to nodes, while dragging the guide around
671 void Inkscape::ObjectSnapper::guideSnap(SnappedConstraints &sc,
672 Geom::Point const &p,
673 Geom::Point const &guide_normal) const
674 {
675 /* Get a list of all the SPItems that we will try to snap to */
676 std::vector<SPItem*> cand;
677 std::vector<SPItem const *> const it; //just an empty list
679 DimensionToSnap snap_dim;
680 if (guide_normal == to_2geom(component_vectors[Geom::Y])) {
681 snap_dim = GUIDE_TRANSL_SNAP_Y;
682 } else if (guide_normal == to_2geom(component_vectors[Geom::X])) {
683 snap_dim = GUIDE_TRANSL_SNAP_X;
684 } else {
685 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
686 }
688 // We don't support ANGLED_GUIDE_ROT_SNAP yet.
690 // It would be cool to allow the user to rotate a guide by dragging it, instead of
691 // only translating it. (For example when CTRL is pressed). We will need an UI part
692 // for that first; and some important usability choices need to be made:
693 // E.g. which point should be used for pivoting? A previously snapped point,
694 // or a transformation center (which can be moved after clicking for the
695 // second time on an object; but should this point then be constrained to the
696 // line, or can it be located anywhere?)
698 _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), snap_dim, false, Geom::identity());
699 _snapTranslatingGuideToNodes(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, guide_normal);
700 // _snapRotatingGuideToNodes has not been implemented yet.
701 }
703 /**
704 * \return true if this Snapper will snap at least one kind of point.
705 */
706 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
707 {
708 bool snap_to_something = _snapmanager->snapprefs.getSnapToItemPath()
709 || _snapmanager->snapprefs.getSnapToItemNode()
710 || _snapmanager->snapprefs.getSnapToBBoxPath()
711 || _snapmanager->snapprefs.getSnapToBBoxNode()
712 || _snapmanager->snapprefs.getSnapToPageBorder()
713 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
714 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
715 || _snapmanager->snapprefs.getIncludeItemCenter();
717 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeBBoxOrNodes() && snap_to_something);
718 }
720 bool Inkscape::ObjectSnapper::GuidesMightSnap() const
721 {
722 bool snap_to_something = _snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapToBBoxNode();
723 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeGuide() && snap_to_something);
724 }
726 void Inkscape::ObjectSnapper::_clear_paths() const
727 {
728 for (std::vector<std::pair<Geom::PathVector*, SnapTargetType> >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
729 g_free(k->first);
730 }
731 _paths_to_snap_to->clear();
732 }
734 Geom::PathVector* Inkscape::ObjectSnapper::_getBorderPathv() const
735 {
736 Geom::Rect const border_rect = Geom::Rect(Geom::Point(0,0), Geom::Point(sp_document_width(_snapmanager->getDocument()),sp_document_height(_snapmanager->getDocument())));
737 return _getPathvFromRect(border_rect);
738 }
740 Geom::PathVector* Inkscape::ObjectSnapper::_getPathvFromRect(Geom::Rect const rect) const
741 {
742 SPCurve const *border_curve = SPCurve::new_from_rect(rect);
743 if (border_curve) {
744 Geom::PathVector *dummy = new Geom::PathVector(border_curve->get_pathvector());
745 return dummy;
746 } else {
747 return NULL;
748 }
749 }
751 void Inkscape::ObjectSnapper::_getBorderNodes(std::vector<std::pair<Geom::Point, int> > *points) const
752 {
753 Geom::Coord w = sp_document_width(_snapmanager->getDocument());
754 Geom::Coord h = sp_document_height(_snapmanager->getDocument());
755 points->push_back(std::make_pair(Geom::Point(0,0), SNAPTARGET_PAGE_CORNER));
756 points->push_back(std::make_pair(Geom::Point(0,h), SNAPTARGET_PAGE_CORNER));
757 points->push_back(std::make_pair(Geom::Point(w,h), SNAPTARGET_PAGE_CORNER));
758 points->push_back(std::make_pair(Geom::Point(w,0), SNAPTARGET_PAGE_CORNER));
759 }
761 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)
762 {
763 if (bbox) {
764 // collect the corners of the bounding box
765 for ( unsigned k = 0 ; k < 4 ; k++ ) {
766 if (includeCorners) {
767 points->push_back(std::make_pair((bbox->corner(k)), isTarget ? int(Inkscape::SNAPTARGET_BBOX_CORNER) : int(Inkscape::SNAPSOURCE_BBOX_CORNER)));
768 }
769 // optionally, collect the midpoints of the bounding box's edges too
770 if (includeLineMidpoints) {
771 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)));
772 }
773 }
774 if (includeObjectMidpoints) {
775 points->push_back(std::make_pair(bbox->midpoint(), isTarget ? int(Inkscape::SNAPTARGET_BBOX_MIDPOINT) : int(Inkscape::SNAPSOURCE_BBOX_MIDPOINT)));
776 }
777 }
778 }
780 /*
781 Local Variables:
782 mode:c++
783 c-file-style:"stroustrup"
784 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
785 indent-tabs-mode:nil
786 fill-column:99
787 End:
788 */
789 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :