515008964e2864432beda0c36ceb10edce3f9ea1
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<Geom::Point>;
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
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, SnapPointsIter(*_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, _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 bool const &first_point,
262 std::vector<Geom::Point> *unselected_nodes) const
263 {
264 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
266 _collectNodes(t, first_point);
268 if (unselected_nodes != NULL) {
269 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
270 }
272 SnappedPoint s;
273 bool success = false;
275 for (std::vector<Geom::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
276 Geom::Coord dist = Geom::L2(*k - p);
277 if (dist < getSnapperTolerance() && dist < s.getSnapDistance()) {
278 s = SnappedPoint(*k, SNAPTARGET_NODE, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
279 success = true;
280 }
281 }
283 if (success) {
284 sc.points.push_back(s);
285 }
286 }
288 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
289 Inkscape::SnapPreferences::PointType const &t,
290 Geom::Point const &p,
291 Geom::Point const &guide_normal) const
292 {
293 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
294 _collectNodes(t, true);
296 SnappedPoint s;
297 bool success = false;
299 Geom::Coord tol = getSnapperTolerance();
301 for (std::vector<Geom::Point>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
302 // Project each node (*k) on the guide line (running through point p)
303 Geom::Point p_proj = project_on_linesegment(*k, p, p + Geom::rot90(guide_normal));
304 Geom::Coord dist = Geom::L2(*k - p_proj); // distance from node to the guide
305 Geom::Coord dist2 = Geom::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
306 if ((dist < tol && dist2 < tol) || (getSnapperAlwaysSnap() && dist < s.getSnapDistance())) {
307 s = SnappedPoint(*k, SNAPTARGET_NODE, dist, tol, getSnapperAlwaysSnap(), true);
308 success = true;
309 }
310 }
312 if (success) {
313 sc.points.push_back(s);
314 }
315 }
318 /**
319 * Returns index of first NR_END bpath in array.
320 */
322 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::SnapPreferences::PointType const &t,
323 bool const &first_point) const
324 {
325 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
326 // e.g. when translating an item using the selector tool, then we will only do this for the
327 // first point and store the collection for later use. This significantly improves the performance
328 if (first_point) {
329 _clear_paths();
331 // Determine the type of bounding box we should snap to
332 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
334 bool p_is_a_node = t & Inkscape::SnapPreferences::SNAPPOINT_NODE;
336 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
337 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
338 int prefs_bbox = prefs->getBool("/tools/bounding_box", 0);
339 bbox_type = !prefs_bbox ?
340 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
341 }
343 // Consider the page border for snapping
344 if (_snapmanager->snapprefs.getSnapToPageBorder()) {
345 Geom::PathVector *border_path = _getBorderPathv();
346 if (border_path != NULL) {
347 _paths_to_snap_to->push_back(std::make_pair<Geom::PathVector*, SnapTargetType>(border_path, SNAPTARGET_PAGE_BORDER));
348 }
349 }
351 for (std::vector<SnapCandidate>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
353 /* Transform the requested snap point to this item's coordinates */
354 Geom::Matrix i2doc(Geom::identity());
355 SPItem *root_item = NULL;
356 /* We might have a clone at hand, so make sure we get the root item */
357 if (SP_IS_USE((*i).item)) {
358 i2doc = sp_use_get_root_transform(SP_USE((*i).item));
359 root_item = sp_use_root(SP_USE((*i).item));
360 g_return_if_fail(root_item);
361 } else {
362 i2doc = sp_item_i2doc_affine((*i).item);
363 root_item = (*i).item;
364 }
366 //Build a list of all paths considered for snapping to
368 //Add the item's path to snap to
369 if (_snapmanager->snapprefs.getSnapToItemPath()) {
370 if (!(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node)) {
371 // Snapping to the path of characters is very cool, but for a large
372 // chunk of text this will take ages! So limit snapping to text paths
373 // containing max. 240 characters. Snapping the bbox will not be affected
374 bool very_lenghty_prose = false;
375 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
376 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
377 }
378 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
379 // which corresponds to a lag of 500 msec. This is for snapping a rect
380 // to a single line of text.
382 // Snapping for example to a traced bitmap is also very stressing for
383 // the CPU, so we'll only snap to paths having no more than 500 nodes
384 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
385 bool very_complex_path = false;
386 if (SP_IS_PATH(root_item)) {
387 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
388 }
390 if (!very_lenghty_prose && !very_complex_path) {
391 SPCurve *curve = curve_for_item(root_item);
392 if (curve) {
393 // We will get our own copy of the path, which must be freed at some point
394 Geom::PathVector *borderpathv = pathvector_for_curve(root_item, curve, true, true, Geom::identity(), (*i).additional_affine);
395 _paths_to_snap_to->push_back(std::make_pair<Geom::PathVector*, SnapTargetType>(borderpathv, SNAPTARGET_PATH)); // Perhaps for speed, get a reference to the Geom::pathvector, and store the transformation besides it.
396 curve->unref();
397 }
398 }
399 }
400 }
402 //Add the item's bounding box to snap to
403 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
404 if (!(_snapmanager->snapprefs.getStrictSnapping() && p_is_a_node)) {
405 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
406 // of the item AND the bbox of the clipping path at the same time
407 if (!(*i).clip_or_mask) {
408 Geom::OptRect rect;
409 sp_item_invoke_bbox(root_item, rect, i2doc, TRUE, bbox_type);
410 if (rect) {
411 Geom::PathVector *path = _getPathvFromRect(*rect);
412 _paths_to_snap_to->push_back(std::make_pair<Geom::PathVector*, SnapTargetType>(path, SNAPTARGET_BBOX_EDGE));
413 }
414 }
415 }
416 }
417 }
418 }
419 }
421 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
422 Inkscape::SnapPreferences::PointType const &t,
423 Geom::Point const &p,
424 bool const &first_point,
425 std::vector<Geom::Point> *unselected_nodes,
426 SPPath const *selected_path) const
427 {
428 _collectPaths(t, first_point);
429 // Now we can finally do the real snapping, using the paths collected above
431 g_assert(_snapmanager->getDesktop() != NULL);
432 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p);
434 bool const node_tool_active = _snapmanager->snapprefs.getSnapToItemPath() && selected_path != NULL;
436 if (first_point) {
437 /* findCandidates() is used for snapping to both paths and nodes. It ignores the path that is
438 * currently being edited, because that path requires special care: when snapping to nodes
439 * only the unselected nodes of that path should be considered, and these will be passed on separately.
440 * This path must not be ignored however when snapping to the paths, so we add it here
441 * manually when applicable.
442 *
443 * Note that this path must be the last in line!
444 * */
445 if (node_tool_active) {
446 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
447 if (curve) {
448 Geom::PathVector *pathv = pathvector_for_curve(SP_ITEM(selected_path), curve, true, true, Geom::identity(), Geom::identity()); // We will get our own copy of the path, which must be freed at some point
449 _paths_to_snap_to->push_back(std::make_pair<Geom::PathVector*, SnapTargetType>(pathv, SNAPTARGET_PATH));
450 curve->unref();
451 }
452 }
453 }
455 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++) {
456 bool const being_edited = (node_tool_active && (*it_p) == _paths_to_snap_to->back());
457 //if true then this pathvector it_pv is currently being edited in the node tool
459 // char * svgd = sp_svg_write_path(**it_p->first);
460 // std::cout << "Dumping the pathvector: " << svgd << std::endl;
462 for(Geom::PathVector::iterator it_pv = (it_p->first)->begin(); it_pv != (it_p->first)->end(); ++it_pv) {
463 // Find a nearest point for each curve within this path
464 // n curves will return n time values with 0 <= t <= 1
465 std::vector<double> anp = (*it_pv).nearestPointPerCurve(p_doc);
467 std::vector<double>::const_iterator np = anp.begin();
468 unsigned int index = 0;
469 for (; np != anp.end(); np++, index++) {
470 Geom::Curve const *curve = &((*it_pv).at_index(index));
471 Geom::Point const sp_doc = curve->pointAt(*np);
473 bool c1 = true;
474 bool c2 = true;
475 if (being_edited) {
476 /* If the path is being edited, then we should only snap though to stationary pieces of the path
477 * and not to the pieces that are being dragged around. This way we avoid
478 * self-snapping. For this we check whether the nodes at both ends of the current
479 * piece are unselected; if they are then this piece must be stationary
480 */
481 g_assert(unselected_nodes != NULL);
482 Geom::Point start_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(0));
483 Geom::Point end_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(1));
484 c1 = isUnselectedNode(start_pt, unselected_nodes);
485 c2 = isUnselectedNode(end_pt, unselected_nodes);
486 /* Unfortunately, this might yield false positives for coincident nodes. Inkscape might therefore mistakenly
487 * snap to path segments that are not stationary. There are at least two possible ways to overcome this:
488 * - Linking the individual nodes of the SPPath we have here, to the nodes of the NodePath::SubPath class as being
489 * used in sp_nodepath_selected_nodes_move. This class has a member variable called "selected". For this the nodes
490 * should be in the exact same order for both classes, so we can index them
491 * - Replacing the SPPath being used here by the the NodePath::SubPath class; but how?
492 */
493 }
495 Geom::Point const sp_dt = _snapmanager->getDesktop()->doc2dt(sp_doc);
496 if (!being_edited || (c1 && c2)) {
497 Geom::Coord const dist = Geom::distance(sp_doc, p_doc);
498 if (dist < getSnapperTolerance()) {
499 sc.curves.push_back(Inkscape::SnappedCurve(sp_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), false, curve, it_p->second));
500 }
501 }
502 }
503 } // End of: for (Geom::PathVector::iterator ....)
504 }
505 }
507 /* Returns true if point is coincident with one of the unselected nodes */
508 bool Inkscape::ObjectSnapper::isUnselectedNode(Geom::Point const &point, std::vector<Geom::Point> const *unselected_nodes) const
509 {
510 if (unselected_nodes == NULL) {
511 return false;
512 }
514 if (unselected_nodes->size() == 0) {
515 return false;
516 }
518 for (std::vector<Geom::Point>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
519 if (Geom::L2(point - *i) < 1e-4) {
520 return true;
521 }
522 }
524 return false;
525 }
527 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
528 Inkscape::SnapPreferences::PointType const &t,
529 Geom::Point const &p,
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 Geom::Point const p1_on_cl = c.hasPoint() ? c.getPoint() : p;
547 Geom::Point const p2_on_cl = p1_on_cl + direction_vector;
549 // The intersection point of the constraint line with any path,
550 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
551 // The distance between those points is twice the snapping tolerance
552 Geom::Point const p_proj_on_cl = project_on_linesegment(p, p1_on_cl, p2_on_cl);
553 Geom::Point const p_min_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
554 Geom::Point const p_max_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
556 Geom::Path cl;
557 std::vector<Geom::Path> clv;
558 cl.start(p_min_on_cl);
559 cl.appendNew<Geom::LineSegment>(p_max_on_cl);
560 clv.push_back(cl);
562 for (std::vector<std::pair<Geom::PathVector*, SnapTargetType> >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
563 if (k->first) {
564 Geom::CrossingSet cs = Geom::crossings(clv, *(k->first));
565 if (cs.size() > 0) {
566 // We need only the first element of cs, because cl is only a single straight linesegment
567 // This first element contains a vector filled with crossings of cl with k->first
568 for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
569 if ((*m).ta >= 0 && (*m).ta <= 1 ) {
570 // Reconstruct the point of intersection
571 Geom::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
572 // When it's within snapping range, then return it
573 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
574 Geom::Coord dist = Geom::L2(_snapmanager->getDesktop()->dt2doc(p_proj_on_cl) - p_inters);
575 SnappedPoint s(_snapmanager->getDesktop()->doc2dt(p_inters), k->second, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true);
576 sc.points.push_back(s);
577 }
578 }
579 }
580 }
581 }
582 }
585 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
586 Inkscape::SnapPreferences::PointType const &t,
587 Geom::Point const &p,
588 bool const &first_point,
589 Geom::OptRect const &bbox_to_snap,
590 std::vector<SPItem const *> const *it,
591 std::vector<Geom::Point> *unselected_nodes) const
592 {
593 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(t) == false ) {
594 return;
595 }
597 /* Get a list of all the SPItems that we will try to snap to */
598 if (first_point) {
599 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p, p);
600 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, first_point, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
601 }
603 if (_snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapSmoothNodes()
604 || _snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapToPageBorder()
605 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
606 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
607 || _snapmanager->snapprefs.getIncludeItemCenter()) {
608 _snapNodes(sc, t, p, first_point, unselected_nodes);
609 }
611 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
612 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
613 if (n > 0) {
614 /* While editing a path in the node tool, findCandidates must ignore that path because
615 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
616 * That path must not be ignored however when snapping to the paths, so we add it here
617 * manually when applicable
618 */
619 SPPath *path = NULL;
620 if (it != NULL) {
621 g_assert(SP_IS_PATH(*it->begin()));
622 g_assert(it->size() == 1);
623 path = SP_PATH(*it->begin());
624 }
625 _snapPaths(sc, t, p, first_point, unselected_nodes, path);
626 } else {
627 _snapPaths(sc, t, p, first_point, NULL, NULL);
628 }
629 }
630 }
632 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
633 Inkscape::SnapPreferences::PointType const &t,
634 Geom::Point const &p,
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 usefull 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, 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<Geom::Point> *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(Geom::Point(0,0));
751 points->push_back(Geom::Point(0,h));
752 points->push_back(Geom::Point(w,h));
753 points->push_back(Geom::Point(w,0));
754 }
756 void Inkscape::getBBoxPoints(Geom::OptRect const bbox, std::vector<Geom::Point> *points, 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(bbox->corner(k));
763 }
764 // optionally, collect the midpoints of the bounding box's edges too
765 if (includeLineMidpoints) {
766 points->push_back((bbox->corner(k) + bbox->corner((k+1) % 4))/2);
767 }
768 }
769 if (includeObjectMidpoints) {
770 points->push_back(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 :