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 <2geom/line.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::SnapCandidate::SnapCandidate(SPItem* item, bool clip_or_mask, Geom::Matrix additional_affine)
39 : item(item), clip_or_mask(clip_or_mask), additional_affine(additional_affine)
40 {
41 }
43 Inkscape::SnapCandidate::~SnapCandidate()
44 {
45 }
47 Inkscape::ObjectSnapper::ObjectSnapper(SnapManager *sm, Geom::Coord const d)
48 : Snapper(sm, d)
49 {
50 _candidates = new std::vector<SnapCandidate>;
51 _points_to_snap_to = new std::vector<std::pair<Geom::Point, int> >;
52 _paths_to_snap_to = new std::vector<std::pair<Geom::PathVector*, SnapTargetType> >;
53 }
55 Inkscape::ObjectSnapper::~ObjectSnapper()
56 {
57 _candidates->clear();
58 delete _candidates;
60 _points_to_snap_to->clear();
61 delete _points_to_snap_to;
63 _clear_paths();
64 delete _paths_to_snap_to;
65 }
67 /**
68 * \return Snap tolerance (desktop coordinates); depends on current zoom so that it's always the same in screen pixels
69 */
70 Geom::Coord Inkscape::ObjectSnapper::getSnapperTolerance() const
71 {
72 SPDesktop const *dt = _snapmanager->getDesktop();
73 double const zoom = dt ? dt->current_zoom() : 1;
74 return _snapmanager->snapprefs.getObjectTolerance() / zoom;
75 }
77 bool Inkscape::ObjectSnapper::getSnapperAlwaysSnap() const
78 {
79 return _snapmanager->snapprefs.getObjectTolerance() == 10000; //TODO: Replace this threshold of 10000 by a constant; see also tolerance-slider.cpp
80 }
82 /**
83 * Find all items within snapping range.
84 * \param parent Pointer to the document's root, or to a clipped path or mask object
85 * \param it List of items to ignore
86 * \param first_point If true then this point is the first one from a whole bunch of points
87 * \param bbox_to_snap Bounding box hulling the whole bunch of points, all from the same selection and having the same transformation
88 * \param DimensionToSnap Snap in X, Y, or both directions.
89 */
91 void Inkscape::ObjectSnapper::_findCandidates(SPObject* parent,
92 std::vector<SPItem const *> const *it,
93 bool const &first_point,
94 Geom::Rect const &bbox_to_snap,
95 DimensionToSnap const snap_dim,
96 bool const clip_or_mask,
97 Geom::Matrix const additional_affine) const // transformation of the item being clipped / masked
98 {
99 bool const c1 = (snap_dim == TRANSL_SNAP_XY) && ThisSnapperMightSnap();
100 bool const c2 = (snap_dim != TRANSL_SNAP_XY) && GuidesMightSnap();
102 if (!(c1 || c2)) {
103 return;
104 }
106 if (first_point) {
107 _candidates->clear();
108 }
110 Geom::Rect bbox_to_snap_incl = bbox_to_snap; // _incl means: will include the snapper tolerance
111 bbox_to_snap_incl.expandBy(getSnapperTolerance()); // see?
113 for (SPObject* o = sp_object_first_child(parent); o != NULL; o = SP_OBJECT_NEXT(o)) {
114 g_assert(_snapmanager->getDesktop() != NULL);
115 if (SP_IS_ITEM(o) && !(_snapmanager->getDesktop()->itemIsHidden(SP_ITEM(o)) && !clip_or_mask)) {
116 // Snapping to items in a locked layer is allowed
117 // Don't snap to hidden objects, unless they're a clipped path or a mask
118 /* See if this item is on the ignore list */
119 std::vector<SPItem const *>::const_iterator i;
120 if (it != NULL) {
121 i = it->begin();
122 while (i != it->end() && *i != o) {
123 i++;
124 }
125 }
127 if (it == NULL || i == it->end()) {
128 SPItem *item = SP_ITEM(o);
129 if (item) {
130 SPObject *obj = NULL;
131 if (!clip_or_mask) { // cannot clip or mask more than once
132 // The current item is not a clipping path or a mask, but might
133 // still be the subject of clipping or masking itself ; if so, then
134 // we should also consider that path or mask for snapping to
135 obj = SP_OBJECT(item->clip_ref->getObject());
136 if (obj) {
137 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
138 }
139 obj = SP_OBJECT(item->mask_ref->getObject());
140 if (obj) {
141 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
142 }
143 }
144 }
146 if (SP_IS_GROUP(o)) {
147 _findCandidates(o, it, false, bbox_to_snap, snap_dim, clip_or_mask, additional_affine);
148 } else {
149 Geom::OptRect bbox_of_item = Geom::Rect();
150 if (clip_or_mask) {
151 // Oh oh, this will get ugly. We cannot use sp_item_i2d_affine directly because we need to
152 // insert an additional transformation in document coordinates (code copied from sp_item_i2d_affine)
153 sp_item_invoke_bbox(item,
154 bbox_of_item,
155 sp_item_i2doc_affine(item) * additional_affine * _snapmanager->getDesktop()->doc2dt(),
156 true);
157 } else {
158 sp_item_invoke_bbox(item, bbox_of_item, sp_item_i2d_affine(item), true);
159 }
160 if (bbox_of_item) {
161 // See if the item is within range
162 if (bbox_to_snap_incl.intersects(*bbox_of_item)) {
163 // This item is within snapping range, so record it as a candidate
164 _candidates->push_back(SnapCandidate(item, clip_or_mask, additional_affine));
165 // For debugging: print the id of the candidate to the console
166 // SPObject *obj = (SPObject*)item;
167 // std::cout << "Snap candidate added: " << obj->id << std::endl;
168 }
169 }
170 }
171 }
172 }
173 }
174 }
177 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::SnapPreferences::PointType const &t,
178 bool const &first_point) const
179 {
180 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
181 // e.g. when translating an item using the selector tool, then we will only do this for the
182 // first point and store the collection for later use. This significantly improves the performance
183 if (first_point) {
184 _points_to_snap_to->clear();
186 // Determine the type of bounding box we should snap to
187 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
189 bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
190 bool p_is_a_bbox = t & Inkscape::SnapPreferences::SNAPPOINT_BBOX;
191 bool p_is_a_guide = t & Inkscape::SnapPreferences::SNAPPOINT_GUIDE;
193 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
194 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)));
196 if (_snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()) {
197 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
198 bool prefs_bbox = prefs->getBool("/tools/bounding_box");
199 bbox_type = !prefs_bbox ?
200 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
201 }
203 // Consider the page border for snapping to
204 if (_snapmanager->snapprefs.getSnapToPageBorder()) {
205 _getBorderNodes(_points_to_snap_to);
206 }
208 for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
209 //Geom::Matrix i2doc(Geom::identity());
210 SPItem *root_item = (*i).item;
211 if (SP_IS_USE((*i).item)) {
212 root_item = sp_use_root(SP_USE((*i).item));
213 }
214 g_return_if_fail(root_item);
216 //Collect all nodes so we can snap to them
217 if (p_is_a_node || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node) || p_is_a_guide) {
218 // Note: there are two ways in which intersections are considered:
219 // Method 1: Intersections are calculated for each shape individually, for both the
220 // snap source and snap target (see sp_shape_snappoints)
221 // Method 2: Intersections are calculated for each curve or line that we've snapped to, i.e. only for
222 // the target (see the intersect() method in the SnappedCurve and SnappedLine classes)
223 // Some differences:
224 // - Method 1 doesn't find intersections within a set of multiple objects
225 // - Method 2 only works for targets
226 // When considering intersections as snap targets:
227 // - Method 1 only works when snapping to nodes, whereas
228 // - Method 2 only works when snapping to paths
229 // - There will be performance differences too!
230 // If both methods are being used simultaneously, then this might lead to duplicate targets!
232 // Well, here we will be looking for snap TARGETS. Both methods can therefore be used.
233 // When snapping to paths, we will get a collection of snapped lines and snapped curves. findBestSnap() will
234 // go hunting for intersections (but only when asked to in the prefs of course). In that case we can just
235 // temporarily block the intersections in sp_item_snappoints, we don't need duplicates. If we're not snapping to
236 // paths though but only to item nodes then we should still look for the intersections in sp_item_snappoints()
237 bool old_pref = _snapmanager->snapprefs.getSnapIntersectionCS();
238 if (_snapmanager->snapprefs.getSnapToItemPath()) {
239 _snapmanager->snapprefs.setSnapIntersectionCS(false);
240 }
242 sp_item_snappoints(root_item, true, *_points_to_snap_to, &_snapmanager->snapprefs);
244 if (_snapmanager->snapprefs.getSnapToItemPath()) {
245 _snapmanager->snapprefs.setSnapIntersectionCS(old_pref);
246 }
247 }
249 //Collect the bounding box's corners so we can snap to them
250 if (p_is_a_bbox || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_bbox) || p_is_a_guide) {
251 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
252 // of the item AND the bbox of the clipping path at the same time
253 if (!(*i).clip_or_mask) {
254 Geom::OptRect b = sp_item_bbox_desktop(root_item, bbox_type);
255 getBBoxPoints(b, _points_to_snap_to, true, _snapmanager->snapprefs.getSnapToBBoxNode(), _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints(), _snapmanager->snapprefs.getSnapBBoxMidpoints());
256 }
257 }
258 }
259 }
260 }
262 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
263 Inkscape::SnapPreferences::PointType const &t,
264 Geom::Point const &p,
265 SnapSourceType const &source_type,
266 bool const &first_point,
267 std::vector<std::pair<Geom::Point, int> > *unselected_nodes) const
268 {
269 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
271 _collectNodes(t, first_point);
273 if (unselected_nodes != NULL) {
274 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
275 }
277 SnappedPoint s;
278 bool success = false;
280 for (std::vector<std::pair<Geom::Point, int> >::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
281 Geom::Coord dist = Geom::L2((*k).first - p);
282 if (dist < getSnapperTolerance() && dist < s.getSnapDistance()) {
283 s = SnappedPoint((*k).first, source_type, static_cast<Inkscape::SnapTargetType>((*k).second), dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
284 success = true;
285 }
286 }
288 if (success) {
289 sc.points.push_back(s);
290 }
291 }
293 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
294 Inkscape::SnapPreferences::PointType const &t,
295 Geom::Point const &p,
296 Geom::Point const &guide_normal) const
297 {
298 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
299 _collectNodes(t, true);
301 SnappedPoint s;
302 bool success = false;
304 Geom::Coord tol = getSnapperTolerance();
306 for (std::vector<std::pair<Geom::Point, int> >::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
307 // Project each node (*k) on the guide line (running through point p)
308 Geom::Point p_proj = Geom::projection((*k).first, Geom::Line(p, p + Geom::rot90(guide_normal)));
309 Geom::Coord dist = Geom::L2((*k).first - p_proj); // distance from node to the guide
310 Geom::Coord dist2 = Geom::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
311 if ((dist < tol && dist2 < tol) || (getSnapperAlwaysSnap() && dist < s.getSnapDistance())) {
312 s = SnappedPoint((*k).first, SNAPSOURCE_GUIDE, static_cast<Inkscape::SnapTargetType>((*k).second), dist, tol, getSnapperAlwaysSnap(), true);
313 success = true;
314 }
315 }
317 if (success) {
318 sc.points.push_back(s);
319 }
320 }
323 /**
324 * Returns index of first NR_END bpath in array.
325 */
327 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::SnapPreferences::PointType const &t,
328 bool const &first_point) const
329 {
330 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
331 // e.g. when translating an item using the selector tool, then we will only do this for the
332 // first point and store the collection for later use. This significantly improves the performance
333 if (first_point) {
334 _clear_paths();
336 // Determine the type of bounding box we should snap to
337 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
339 bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
341 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
342 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
343 int prefs_bbox = prefs->getBool("/tools/bounding_box", 0);
344 bbox_type = !prefs_bbox ?
345 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
346 }
348 // Consider the page border for snapping
349 if (_snapmanager->snapprefs.getSnapToPageBorder()) {
350 Geom::PathVector *border_path = _getBorderPathv();
351 if (border_path != NULL) {
352 _paths_to_snap_to->push_back(std::make_pair(border_path, SNAPTARGET_PAGE_BORDER));
353 }
354 }
356 for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
358 /* Transform the requested snap point to this item's coordinates */
359 Geom::Matrix i2doc(Geom::identity());
360 SPItem *root_item = NULL;
361 /* We might have a clone at hand, so make sure we get the root item */
362 if (SP_IS_USE((*i).item)) {
363 i2doc = sp_use_get_root_transform(SP_USE((*i).item));
364 root_item = sp_use_root(SP_USE((*i).item));
365 g_return_if_fail(root_item);
366 } else {
367 i2doc = sp_item_i2doc_affine((*i).item);
368 root_item = (*i).item;
369 }
371 //Build a list of all paths considered for snapping to
373 //Add the item's path to snap to
374 if (_snapmanager->snapprefs.getSnapToItemPath()) {
375 if (!(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node)) {
376 // Snapping to the path of characters is very cool, but for a large
377 // chunk of text this will take ages! So limit snapping to text paths
378 // containing max. 240 characters. Snapping the bbox will not be affected
379 bool very_lenghty_prose = false;
380 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
381 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
382 }
383 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
384 // which corresponds to a lag of 500 msec. This is for snapping a rect
385 // to a single line of text.
387 // Snapping for example to a traced bitmap is also very stressing for
388 // the CPU, so we'll only snap to paths having no more than 500 nodes
389 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
390 bool very_complex_path = false;
391 if (SP_IS_PATH(root_item)) {
392 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
393 }
395 if (!very_lenghty_prose && !very_complex_path) {
396 SPCurve *curve = curve_for_item(root_item);
397 if (curve) {
398 // We will get our own copy of the path, which must be freed at some point
399 Geom::PathVector *borderpathv = pathvector_for_curve(root_item, curve, true, true, Geom::identity(), (*i).additional_affine);
400 _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.
401 curve->unref();
402 }
403 }
404 }
405 }
407 //Add the item's bounding box to snap to
408 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
409 if (!(_snapmanager->snapprefs.getStrictSnapping() && p_is_a_node)) {
410 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
411 // of the item AND the bbox of the clipping path at the same time
412 if (!(*i).clip_or_mask) {
413 Geom::OptRect rect;
414 sp_item_invoke_bbox(root_item, rect, i2doc, TRUE, bbox_type);
415 if (rect) {
416 Geom::PathVector *path = _getPathvFromRect(*rect);
417 _paths_to_snap_to->push_back(std::make_pair(path, SNAPTARGET_BBOX_EDGE));
418 }
419 }
420 }
421 }
422 }
423 }
424 }
426 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
427 Inkscape::SnapPreferences::PointType const &t,
428 Geom::Point const &p,
429 SnapSourceType const &source_type,
430 bool const &first_point,
431 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
432 SPPath const *selected_path) const
433 {
434 _collectPaths(t, first_point);
435 // Now we can finally do the real snapping, using the paths collected above
437 g_assert(_snapmanager->getDesktop() != NULL);
438 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p);
440 bool const node_tool_active = _snapmanager->snapprefs.getSnapToItemPath() && selected_path != NULL;
442 if (first_point) {
443 /* findCandidates() is used for snapping to both paths and nodes. It ignores the path that is
444 * currently being edited, because that path requires special care: when snapping to nodes
445 * only the unselected nodes of that path should be considered, and these will be passed on separately.
446 * This path must not be ignored however when snapping to the paths, so we add it here
447 * manually when applicable.
448 *
449 * Note that this path must be the last in line!
450 * */
451 if (node_tool_active) {
452 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
453 if (curve) {
454 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
455 _paths_to_snap_to->push_back(std::make_pair(pathv, SNAPTARGET_PATH));
456 curve->unref();
457 }
458 }
459 }
461 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++) {
462 bool const being_edited = (node_tool_active && (*it_p) == _paths_to_snap_to->back());
463 //if true then this pathvector it_pv is currently being edited in the node tool
465 // char * svgd = sp_svg_write_path(**it_p->first);
466 // std::cout << "Dumping the pathvector: " << svgd << std::endl;
468 for(Geom::PathVector::iterator it_pv = (it_p->first)->begin(); it_pv != (it_p->first)->end(); ++it_pv) {
469 // Find a nearest point for each curve within this path
470 // n curves will return n time values with 0 <= t <= 1
471 std::vector<double> anp = (*it_pv).nearestPointPerCurve(p_doc);
473 std::vector<double>::const_iterator np = anp.begin();
474 unsigned int index = 0;
475 for (; np != anp.end(); np++, index++) {
476 Geom::Curve const *curve = &((*it_pv).at_index(index));
477 Geom::Point const sp_doc = curve->pointAt(*np);
479 bool c1 = true;
480 bool c2 = true;
481 if (being_edited) {
482 /* If the path is being edited, then we should only snap though to stationary pieces of the path
483 * and not to the pieces that are being dragged around. This way we avoid
484 * self-snapping. For this we check whether the nodes at both ends of the current
485 * piece are unselected; if they are then this piece must be stationary
486 */
487 g_assert(unselected_nodes != NULL);
488 Geom::Point start_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(0));
489 Geom::Point end_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(1));
490 c1 = isUnselectedNode(start_pt, unselected_nodes);
491 c2 = isUnselectedNode(end_pt, unselected_nodes);
492 /* Unfortunately, this might yield false positives for coincident nodes. Inkscape might therefore mistakenly
493 * snap to path segments that are not stationary. There are at least two possible ways to overcome this:
494 * - Linking the individual nodes of the SPPath we have here, to the nodes of the NodePath::SubPath class as being
495 * used in sp_nodepath_selected_nodes_move. This class has a member variable called "selected". For this the nodes
496 * should be in the exact same order for both classes, so we can index them
497 * - Replacing the SPPath being used here by the the NodePath::SubPath class; but how?
498 */
499 }
501 Geom::Point const sp_dt = _snapmanager->getDesktop()->doc2dt(sp_doc);
502 if (!being_edited || (c1 && c2)) {
503 Geom::Coord const dist = Geom::distance(sp_doc, p_doc);
504 if (dist < getSnapperTolerance()) {
505 sc.curves.push_back(Inkscape::SnappedCurve(sp_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), false, curve, source_type, it_p->second));
506 }
507 }
508 }
509 } // End of: for (Geom::PathVector::iterator ....)
510 }
511 }
513 /* Returns true if point is coincident with one of the unselected nodes */
514 bool Inkscape::ObjectSnapper::isUnselectedNode(Geom::Point const &point, std::vector<std::pair<Geom::Point, int> > const *unselected_nodes) const
515 {
516 if (unselected_nodes == NULL) {
517 return false;
518 }
520 if (unselected_nodes->size() == 0) {
521 return false;
522 }
524 for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
525 if (Geom::L2(point - (*i).first) < 1e-4) {
526 return true;
527 }
528 }
530 return false;
531 }
533 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
534 Inkscape::SnapPreferences::PointType const &t,
535 Geom::Point const &p,
536 SnapSourceType const source_type,
537 bool const &first_point,
538 ConstraintLine const &c) const
539 {
541 _collectPaths(t, first_point);
543 // Now we can finally do the real snapping, using the paths collected above
545 g_assert(_snapmanager->getDesktop() != NULL);
546 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p);
548 Geom::Point direction_vector = c.getDirection();
549 if (!is_zero(direction_vector)) {
550 direction_vector = Geom::unit_vector(direction_vector);
551 }
553 Geom::Point const p1_on_cl = c.hasPoint() ? c.getPoint() : p;
554 Geom::Point const p2_on_cl = p1_on_cl + direction_vector;
556 // The intersection point of the constraint line with any path,
557 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
558 // The distance between those points is twice the snapping tolerance
559 Geom::Point const p_proj_on_cl = Geom::projection(p, Geom::Line(p1_on_cl, p2_on_cl));
560 Geom::Point const p_min_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
561 Geom::Point const p_max_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
563 Geom::Path cl;
564 std::vector<Geom::Path> clv;
565 cl.start(p_min_on_cl);
566 cl.appendNew<Geom::LineSegment>(p_max_on_cl);
567 clv.push_back(cl);
569 for (std::vector<std::pair<Geom::PathVector*, SnapTargetType> >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
570 if (k->first) {
571 Geom::CrossingSet cs = Geom::crossings(clv, *(k->first));
572 if (cs.size() > 0) {
573 // We need only the first element of cs, because cl is only a single straight linesegment
574 // This first element contains a vector filled with crossings of cl with k->first
575 for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
576 if ((*m).ta >= 0 && (*m).ta <= 1 ) {
577 // Reconstruct the point of intersection
578 Geom::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
579 // When it's within snapping range, then return it
580 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
581 Geom::Coord dist = Geom::L2(_snapmanager->getDesktop()->dt2doc(p_proj_on_cl) - p_inters);
582 SnappedPoint s(_snapmanager->getDesktop()->doc2dt(p_inters), source_type, k->second, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
583 sc.points.push_back(s);
584 }
585 }
586 }
587 }
588 }
589 }
592 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
593 Inkscape::SnapPreferences::PointType const &t,
594 Geom::Point const &p,
595 SnapSourceType const &source_type,
596 bool const &first_point,
597 Geom::OptRect const &bbox_to_snap,
598 std::vector<SPItem const *> const *it,
599 std::vector<std::pair<Geom::Point, int> > *unselected_nodes) const
600 {
601 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false ) {
602 return;
603 }
605 /* Get a list of all the SPItems that we will try to snap to */
606 if (first_point) {
607 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
608 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
609 }
611 if (_snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapSmoothNodes()
612 || _snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapToPageBorder()
613 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
614 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
615 || _snapmanager->snapprefs.getIncludeItemCenter()) {
616 _snapNodes(sc, t, p, source_type, first_point, unselected_nodes);
617 }
619 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
620 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
621 if (n > 0) {
622 /* While editing a path in the node tool, findCandidates must ignore that path because
623 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
624 * That path must not be ignored however when snapping to the paths, so we add it here
625 * manually when applicable
626 */
627 SPPath *path = NULL;
628 if (it != NULL) {
629 g_assert(SP_IS_PATH(*it->begin()));
630 g_assert(it->size() == 1);
631 path = SP_PATH(*it->begin());
632 }
633 _snapPaths(sc, t, p, source_type, first_point, unselected_nodes, path);
634 } else {
635 _snapPaths(sc, t, p, source_type, first_point, NULL, NULL);
636 }
637 }
638 }
640 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
641 Inkscape::SnapPreferences::PointType const &t,
642 Geom::Point const &p,
643 SnapSourceType const &source_type,
644 bool const &first_point,
645 Geom::OptRect const &bbox_to_snap,
646 ConstraintLine const &c,
647 std::vector<SPItem const *> const *it) const
648 {
649 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false) {
650 return;
651 }
653 /* Get a list of all the SPItems that we will try to snap to */
654 if (first_point) {
655 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
656 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
657 }
659 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
660 // This is useful for example when scaling an object while maintaining a fixed aspect ratio. It's
661 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
663 // When snapping to objects, we either snap to their nodes or their paths. It is however very
664 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
665 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
666 // so we will more or less snap to them anyhow.
668 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
669 _snapPathsConstrained(sc, t, p, source_type, first_point, c);
670 }
671 }
674 // This method is used to snap a guide to nodes, while dragging the guide around
675 void Inkscape::ObjectSnapper::guideSnap(SnappedConstraints &sc,
676 Geom::Point const &p,
677 Geom::Point const &guide_normal) const
678 {
679 /* Get a list of all the SPItems that we will try to snap to */
680 std::vector<SPItem*> cand;
681 std::vector<SPItem const *> const it; //just an empty list
683 DimensionToSnap snap_dim;
684 if (guide_normal == to_2geom(component_vectors[Geom::Y])) {
685 snap_dim = GUIDE_TRANSL_SNAP_Y;
686 } else if (guide_normal == to_2geom(component_vectors[Geom::X])) {
687 snap_dim = GUIDE_TRANSL_SNAP_X;
688 } else {
689 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
690 }
692 // We don't support ANGLED_GUIDE_ROT_SNAP yet.
694 // It would be cool to allow the user to rotate a guide by dragging it, instead of
695 // only translating it. (For example when CTRL is pressed). We will need an UI part
696 // for that first; and some important usability choices need to be made:
697 // E.g. which point should be used for pivoting? A previously snapped point,
698 // or a transformation center (which can be moved after clicking for the
699 // second time on an object; but should this point then be constrained to the
700 // line, or can it be located anywhere?)
702 _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), snap_dim, false, Geom::identity());
703 _snapTranslatingGuideToNodes(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, guide_normal);
704 // _snapRotatingGuideToNodes has not been implemented yet.
705 }
707 /**
708 * \return true if this Snapper will snap at least one kind of point.
709 */
710 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
711 {
712 bool snap_to_something = _snapmanager->snapprefs.getSnapToItemPath()
713 || _snapmanager->snapprefs.getSnapToItemNode()
714 || _snapmanager->snapprefs.getSnapToBBoxPath()
715 || _snapmanager->snapprefs.getSnapToBBoxNode()
716 || _snapmanager->snapprefs.getSnapToPageBorder()
717 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
718 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
719 || _snapmanager->snapprefs.getIncludeItemCenter();
721 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeBBoxOrNodes() && snap_to_something);
722 }
724 bool Inkscape::ObjectSnapper::GuidesMightSnap() const
725 {
726 bool snap_to_something = _snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapToBBoxNode();
727 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeGuide() && snap_to_something);
728 }
730 void Inkscape::ObjectSnapper::_clear_paths() const
731 {
732 for (std::vector<std::pair<Geom::PathVector*, SnapTargetType> >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
733 g_free(k->first);
734 }
735 _paths_to_snap_to->clear();
736 }
738 Geom::PathVector* Inkscape::ObjectSnapper::_getBorderPathv() const
739 {
740 Geom::Rect const border_rect = Geom::Rect(Geom::Point(0,0), Geom::Point(sp_document_width(_snapmanager->getDocument()),sp_document_height(_snapmanager->getDocument())));
741 return _getPathvFromRect(border_rect);
742 }
744 Geom::PathVector* Inkscape::ObjectSnapper::_getPathvFromRect(Geom::Rect const rect) const
745 {
746 SPCurve const *border_curve = SPCurve::new_from_rect(rect);
747 if (border_curve) {
748 Geom::PathVector *dummy = new Geom::PathVector(border_curve->get_pathvector());
749 return dummy;
750 } else {
751 return NULL;
752 }
753 }
755 void Inkscape::ObjectSnapper::_getBorderNodes(std::vector<std::pair<Geom::Point, int> > *points) const
756 {
757 Geom::Coord w = sp_document_width(_snapmanager->getDocument());
758 Geom::Coord h = sp_document_height(_snapmanager->getDocument());
759 points->push_back(std::make_pair(Geom::Point(0,0), SNAPTARGET_PAGE_CORNER));
760 points->push_back(std::make_pair(Geom::Point(0,h), SNAPTARGET_PAGE_CORNER));
761 points->push_back(std::make_pair(Geom::Point(w,h), SNAPTARGET_PAGE_CORNER));
762 points->push_back(std::make_pair(Geom::Point(w,0), SNAPTARGET_PAGE_CORNER));
763 }
765 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)
766 {
767 if (bbox) {
768 // collect the corners of the bounding box
769 for ( unsigned k = 0 ; k < 4 ; k++ ) {
770 if (includeCorners) {
771 points->push_back(std::make_pair((bbox->corner(k)), isTarget ? int(Inkscape::SNAPTARGET_BBOX_CORNER) : int(Inkscape::SNAPSOURCE_BBOX_CORNER)));
772 }
773 // optionally, collect the midpoints of the bounding box's edges too
774 if (includeLineMidpoints) {
775 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)));
776 }
777 }
778 if (includeObjectMidpoints) {
779 points->push_back(std::make_pair(bbox->midpoint(), isTarget ? int(Inkscape::SNAPTARGET_BBOX_MIDPOINT) : int(Inkscape::SNAPSOURCE_BBOX_MIDPOINT)));
780 }
781 }
782 }
784 /*
785 Local Variables:
786 mode:c++
787 c-file-style:"stroustrup"
788 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
789 indent-tabs-mode:nil
790 fill-column:99
791 End:
792 */
793 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :