1 /**
2 * \file object-snapper.cpp
3 * \brief Snapping things to objects.
4 *
5 * Authors:
6 * Carl Hetherington <inkscape@carlh.net>
7 * Diederik van Lierop <mail@diedenrezi.nl>
8 *
9 * Copyright (C) 2005 - 2008 Authors
10 *
11 * Released under GNU GPL, read the file 'COPYING' for more information
12 */
14 #include "svg/svg.h"
15 #include <2geom/path-intersection.h>
16 #include <2geom/point.h>
17 #include <2geom/rect.h>
18 #include <2geom/line.h>
19 #include "document.h"
20 #include "sp-namedview.h"
21 #include "sp-image.h"
22 #include "sp-item-group.h"
23 #include "sp-item.h"
24 #include "sp-use.h"
25 #include "display/curve.h"
26 #include "inkscape.h"
27 #include "preferences.h"
28 #include "sp-text.h"
29 #include "sp-flowtext.h"
30 #include "text-editing.h"
31 #include "sp-clippath.h"
32 #include "sp-mask.h"
33 #include "helper/geom-curves.h"
34 #include "desktop.h"
36 Inkscape::ObjectSnapper::ObjectSnapper(SnapManager *sm, Geom::Coord const d)
37 : Snapper(sm, d)
38 {
39 _candidates = new std::vector<SnapCandidateItem>;
40 _points_to_snap_to = new std::vector<Inkscape::SnapCandidatePoint>;
41 _paths_to_snap_to = new std::vector<Inkscape::SnapCandidatePath >;
42 }
44 Inkscape::ObjectSnapper::~ObjectSnapper()
45 {
46 _candidates->clear();
47 delete _candidates;
49 _points_to_snap_to->clear();
50 delete _points_to_snap_to;
52 _clear_paths();
53 delete _paths_to_snap_to;
54 }
56 /**
57 * \return Snap tolerance (desktop coordinates); depends on current zoom so that it's always the same in screen pixels
58 */
59 Geom::Coord Inkscape::ObjectSnapper::getSnapperTolerance() const
60 {
61 SPDesktop const *dt = _snapmanager->getDesktop();
62 double const zoom = dt ? dt->current_zoom() : 1;
63 return _snapmanager->snapprefs.getObjectTolerance() / zoom;
64 }
66 bool Inkscape::ObjectSnapper::getSnapperAlwaysSnap() const
67 {
68 return _snapmanager->snapprefs.getObjectTolerance() == 10000; //TODO: Replace this threshold of 10000 by a constant; see also tolerance-slider.cpp
69 }
71 /**
72 * Find all items within snapping range.
73 * \param parent Pointer to the document's root, or to a clipped path or mask object
74 * \param it List of items to ignore
75 * \param bbox_to_snap Bounding box hulling the whole bunch of points, all from the same selection and having the same transformation
76 * \param DimensionToSnap Snap in X, Y, or both directions.
77 */
79 void Inkscape::ObjectSnapper::_findCandidates(SPObject* parent,
80 std::vector<SPItem const *> const *it,
81 bool const &first_point,
82 Geom::Rect const &bbox_to_snap,
83 DimensionToSnap const snap_dim,
84 bool const clip_or_mask,
85 Geom::Matrix const additional_affine) const // transformation of the item being clipped / masked
86 {
87 bool const c1 = (snap_dim == TRANSL_SNAP_XY) && ThisSnapperMightSnap();
88 bool const c2 = (snap_dim != TRANSL_SNAP_XY) && GuidesMightSnap();
90 if (!(c1 || c2)) {
91 return;
92 }
94 if (first_point) {
95 _candidates->clear();
96 }
98 Geom::Rect bbox_to_snap_incl = bbox_to_snap; // _incl means: will include the snapper tolerance
99 bbox_to_snap_incl.expandBy(getSnapperTolerance()); // see?
101 for (SPObject* o = sp_object_first_child(parent); o != NULL; o = SP_OBJECT_NEXT(o)) {
102 g_assert(_snapmanager->getDesktop() != NULL);
103 if (SP_IS_ITEM(o) && !(_snapmanager->getDesktop()->itemIsHidden(SP_ITEM(o)) && !clip_or_mask)) {
104 // Snapping to items in a locked layer is allowed
105 // Don't snap to hidden objects, unless they're a clipped path or a mask
106 /* See if this item is on the ignore list */
107 std::vector<SPItem const *>::const_iterator i;
108 if (it != NULL) {
109 i = it->begin();
110 while (i != it->end() && *i != o) {
111 i++;
112 }
113 }
115 if (it == NULL || i == it->end()) {
116 SPItem *item = SP_ITEM(o);
117 if (item) {
118 SPObject *obj = NULL;
119 if (!clip_or_mask) { // cannot clip or mask more than once
120 // The current item is not a clipping path or a mask, but might
121 // still be the subject of clipping or masking itself ; if so, then
122 // we should also consider that path or mask for snapping to
123 obj = SP_OBJECT(item->clip_ref->getObject());
124 if (obj) {
125 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
126 }
127 obj = SP_OBJECT(item->mask_ref->getObject());
128 if (obj) {
129 _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
130 }
131 }
132 }
134 if (SP_IS_GROUP(o)) {
135 _findCandidates(o, it, false, bbox_to_snap, snap_dim, clip_or_mask, additional_affine);
136 } else {
137 Geom::OptRect bbox_of_item = Geom::Rect();
138 if (clip_or_mask) {
139 // Oh oh, this will get ugly. We cannot use sp_item_i2d_affine directly because we need to
140 // insert an additional transformation in document coordinates (code copied from sp_item_i2d_affine)
141 sp_item_invoke_bbox(item,
142 bbox_of_item,
143 sp_item_i2doc_affine(item) * additional_affine * _snapmanager->getDesktop()->doc2dt(),
144 true);
145 } else {
146 sp_item_invoke_bbox(item, bbox_of_item, sp_item_i2d_affine(item), true);
147 }
148 if (bbox_of_item) {
149 // See if the item is within range
150 if (bbox_to_snap_incl.intersects(*bbox_of_item)) {
151 // This item is within snapping range, so record it as a candidate
152 _candidates->push_back(SnapCandidateItem(item, clip_or_mask, additional_affine));
153 // For debugging: print the id of the candidate to the console
154 //SPObject *obj = (SPObject*)item;
155 //std::cout << "Snap candidate added: " << obj->id << std::endl;
156 }
157 }
158 }
159 }
160 }
161 }
162 }
165 void Inkscape::ObjectSnapper::_collectNodes(Inkscape::SnapSourceType const &t,
166 bool const &first_point) const
167 {
168 // Now, let's first collect all points to snap to. If we have a whole bunch of points to snap,
169 // e.g. when translating an item using the selector tool, then we will only do this for the
170 // first point and store the collection for later use. This significantly improves the performance
171 if (first_point) {
172 _points_to_snap_to->clear();
174 // Determine the type of bounding box we should snap to
175 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
177 bool p_is_a_node = t & Inkscape::SNAPSOURCE_NODE_CATEGORY;
178 bool p_is_a_bbox = t & Inkscape::SNAPSOURCE_BBOX_CATEGORY;
179 bool p_is_other = t & Inkscape::SNAPSOURCE_OTHER_CATEGORY;
181 // A point considered for snapping should be either a node, a bbox corner or a guide. Pick only ONE!
182 g_assert(!((p_is_a_node && p_is_a_bbox) || (p_is_a_bbox && p_is_other) || (p_is_a_node && p_is_other)));
184 if (_snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()) {
185 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
186 bool prefs_bbox = prefs->getBool("/tools/bounding_box");
187 bbox_type = !prefs_bbox ?
188 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
189 }
191 // Consider the page border for snapping to
192 if (_snapmanager->snapprefs.getSnapToPageBorder()) {
193 _getBorderNodes(_points_to_snap_to);
194 }
196 for (std::vector<SnapCandidateItem>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
197 //Geom::Matrix i2doc(Geom::identity());
198 SPItem *root_item = (*i).item;
199 if (SP_IS_USE((*i).item)) {
200 root_item = sp_use_root(SP_USE((*i).item));
201 }
202 g_return_if_fail(root_item);
204 //Collect all nodes so we can snap to them
205 if (p_is_a_node || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node) || p_is_other) {
206 // Note: there are two ways in which intersections are considered:
207 // Method 1: Intersections are calculated for each shape individually, for both the
208 // snap source and snap target (see sp_shape_snappoints)
209 // Method 2: Intersections are calculated for each curve or line that we've snapped to, i.e. only for
210 // the target (see the intersect() method in the SnappedCurve and SnappedLine classes)
211 // Some differences:
212 // - Method 1 doesn't find intersections within a set of multiple objects
213 // - Method 2 only works for targets
214 // When considering intersections as snap targets:
215 // - Method 1 only works when snapping to nodes, whereas
216 // - Method 2 only works when snapping to paths
217 // - There will be performance differences too!
218 // If both methods are being used simultaneously, then this might lead to duplicate targets!
220 // Well, here we will be looking for snap TARGETS. Both methods can therefore be used.
221 // When snapping to paths, we will get a collection of snapped lines and snapped curves. findBestSnap() will
222 // go hunting for intersections (but only when asked to in the prefs of course). In that case we can just
223 // temporarily block the intersections in sp_item_snappoints, we don't need duplicates. If we're not snapping to
224 // paths though but only to item nodes then we should still look for the intersections in sp_item_snappoints()
225 bool old_pref = _snapmanager->snapprefs.getSnapIntersectionCS();
226 if (_snapmanager->snapprefs.getSnapToItemPath()) {
227 _snapmanager->snapprefs.setSnapIntersectionCS(false);
228 }
230 sp_item_snappoints(root_item, *_points_to_snap_to, &_snapmanager->snapprefs);
232 if (_snapmanager->snapprefs.getSnapToItemPath()) {
233 _snapmanager->snapprefs.setSnapIntersectionCS(old_pref);
234 }
235 }
237 //Collect the bounding box's corners so we can snap to them
238 if (p_is_a_bbox || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_bbox) || p_is_other) {
239 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
240 // of the item AND the bbox of the clipping path at the same time
241 if (!(*i).clip_or_mask) {
242 Geom::OptRect b = sp_item_bbox_desktop(root_item, bbox_type);
243 getBBoxPoints(b, _points_to_snap_to, true, _snapmanager->snapprefs.getSnapToBBoxNode(), _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints(), _snapmanager->snapprefs.getSnapBBoxMidpoints());
244 }
245 }
246 }
247 }
248 }
250 void Inkscape::ObjectSnapper::_snapNodes(SnappedConstraints &sc,
251 Inkscape::SnapCandidatePoint const &p,
252 std::vector<SnapCandidatePoint> *unselected_nodes) const
253 {
254 // Iterate through all nodes, find out which one is the closest to p, and snap to it!
256 _collectNodes(p.getSourceType(), p.getSourceNum() == 0);
258 if (unselected_nodes != NULL) {
259 _points_to_snap_to->insert(_points_to_snap_to->end(), unselected_nodes->begin(), unselected_nodes->end());
260 }
262 SnappedPoint s;
263 bool success = false;
265 for (std::vector<SnapCandidatePoint>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
266 Geom::Coord dist = Geom::L2((*k).getPoint() - p.getPoint());
267 if (dist < getSnapperTolerance() && dist < s.getSnapDistance()) {
268 s = SnappedPoint((*k).getPoint(), p.getSourceType(), p.getSourceNum(), (*k).getTargetType(), dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true, (*k).getTargetBBox());
269 success = true;
270 }
271 }
273 if (success) {
274 sc.points.push_back(s);
275 }
276 }
278 void Inkscape::ObjectSnapper::_snapTranslatingGuideToNodes(SnappedConstraints &sc,
279 Geom::Point const &p,
280 Geom::Point const &guide_normal) const
281 {
282 // Iterate through all nodes, find out which one is the closest to this guide, and snap to it!
283 _collectNodes(SNAPSOURCE_GUIDE, true);
285 // Although we won't snap to paths here (which would give us under constrained snaps) we can still snap to intersections of paths.
286 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
287 _collectPaths(Inkscape::SnapCandidatePoint(p, SNAPSOURCE_GUIDE), true);
288 _snapPaths(sc, Inkscape::SnapCandidatePoint(p, SNAPSOURCE_GUIDE), NULL, NULL);
289 // The paths themselves should be discarded in findBestSnap(), as we should only snap to their intersections
290 }
292 SnappedPoint s;
294 Geom::Coord tol = getSnapperTolerance();
296 for (std::vector<SnapCandidatePoint>::const_iterator k = _points_to_snap_to->begin(); k != _points_to_snap_to->end(); k++) {
297 // Project each node (*k) on the guide line (running through point p)
298 Geom::Point p_proj = Geom::projection((*k).getPoint(), Geom::Line(p, p + Geom::rot90(guide_normal)));
299 Geom::Coord dist = Geom::L2((*k).getPoint() - p_proj); // distance from node to the guide
300 Geom::Coord dist2 = Geom::L2(p - p_proj); // distance from projection of node on the guide, to the mouse location
301 if ((dist < tol && dist2 < tol) || getSnapperAlwaysSnap()) {
302 s = SnappedPoint((*k).getPoint(), SNAPSOURCE_GUIDE, 0, (*k).getTargetType(), dist, tol, getSnapperAlwaysSnap(), true, (*k).getTargetBBox());
303 sc.points.push_back(s);
304 }
305 }
306 }
309 /**
310 * Returns index of first NR_END bpath in array.
311 */
313 void Inkscape::ObjectSnapper::_collectPaths(Inkscape::SnapCandidatePoint const &p,
314 bool const &first_point) const
315 {
316 // Now, let's first collect all paths to snap to. If we have a whole bunch of points to snap,
317 // e.g. when translating an item using the selector tool, then we will only do this for the
318 // first point and store the collection for later use. This significantly improves the performance
319 if (first_point) {
320 _clear_paths();
322 // Determine the type of bounding box we should snap to
323 SPItem::BBoxType bbox_type = SPItem::GEOMETRIC_BBOX;
325 bool p_is_a_node = p.getSourceType() & Inkscape::SNAPSOURCE_NODE_CATEGORY;
326 bool p_is_other = p.getSourceType() & Inkscape::SNAPSOURCE_OTHER_CATEGORY;
328 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
329 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
330 int prefs_bbox = prefs->getBool("/tools/bounding_box", 0);
331 bbox_type = !prefs_bbox ?
332 SPItem::APPROXIMATE_BBOX : SPItem::GEOMETRIC_BBOX;
333 }
335 // Consider the page border for snapping
336 if (_snapmanager->snapprefs.getSnapToPageBorder()) {
337 Geom::PathVector *border_path = _getBorderPathv();
338 if (border_path != NULL) {
339 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(border_path, SNAPTARGET_PAGE_BORDER, Geom::OptRect()));
340 }
341 }
343 for (std::vector<SnapCandidateItem>::const_iterator i = _candidates->begin(); i != _candidates->end(); i++) {
345 /* Transform the requested snap point to this item's coordinates */
346 Geom::Matrix i2doc(Geom::identity());
347 SPItem *root_item = NULL;
348 /* We might have a clone at hand, so make sure we get the root item */
349 if (SP_IS_USE((*i).item)) {
350 i2doc = sp_use_get_root_transform(SP_USE((*i).item));
351 root_item = sp_use_root(SP_USE((*i).item));
352 g_return_if_fail(root_item);
353 } else {
354 i2doc = sp_item_i2doc_affine((*i).item);
355 root_item = (*i).item;
356 }
358 //Build a list of all paths considered for snapping to
360 //Add the item's path to snap to
361 if (_snapmanager->snapprefs.getSnapToItemPath()) {
362 if (p_is_other || !(_snapmanager->snapprefs.getStrictSnapping() && !p_is_a_node)) {
363 // Snapping to the path of characters is very cool, but for a large
364 // chunk of text this will take ages! So limit snapping to text paths
365 // containing max. 240 characters. Snapping the bbox will not be affected
366 bool very_lenghty_prose = false;
367 if (SP_IS_TEXT(root_item) || SP_IS_FLOWTEXT(root_item)) {
368 very_lenghty_prose = sp_text_get_length(SP_TEXT(root_item)) > 240;
369 }
370 // On my AMD 3000+, the snapping lag becomes annoying at approx. 240 chars
371 // which corresponds to a lag of 500 msec. This is for snapping a rect
372 // to a single line of text.
374 // Snapping for example to a traced bitmap is also very stressing for
375 // the CPU, so we'll only snap to paths having no more than 500 nodes
376 // This also leads to a lag of approx. 500 msec (in my lousy test set-up).
377 bool very_complex_path = false;
378 if (SP_IS_PATH(root_item)) {
379 very_complex_path = sp_nodes_in_path(SP_PATH(root_item)) > 500;
380 }
382 if (!very_lenghty_prose && !very_complex_path) {
383 SPCurve *curve = curve_for_item(root_item);
384 if (curve) {
385 // We will get our own copy of the path, which must be freed at some point
386 Geom::PathVector *borderpathv = pathvector_for_curve(root_item, curve, true, true, Geom::identity(), (*i).additional_affine);
387 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(borderpathv, SNAPTARGET_PATH, Geom::OptRect())); // Perhaps for speed, get a reference to the Geom::pathvector, and store the transformation besides it.
388 curve->unref();
389 }
390 }
391 }
392 }
394 //Add the item's bounding box to snap to
395 if (_snapmanager->snapprefs.getSnapToBBoxPath()) {
396 if (p_is_other || !(_snapmanager->snapprefs.getStrictSnapping() && p_is_a_node)) {
397 // Discard the bbox of a clipped path / mask, because we don't want to snap to both the bbox
398 // of the item AND the bbox of the clipping path at the same time
399 if (!(*i).clip_or_mask) {
400 Geom::OptRect rect;
401 sp_item_invoke_bbox(root_item, rect, i2doc, TRUE, bbox_type);
402 if (rect) {
403 Geom::PathVector *path = _getPathvFromRect(*rect);
404 rect = sp_item_bbox_desktop(root_item, bbox_type);
405 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(path, SNAPTARGET_BBOX_EDGE, rect));
406 }
407 }
408 }
409 }
410 }
411 }
412 }
414 void Inkscape::ObjectSnapper::_snapPaths(SnappedConstraints &sc,
415 Inkscape::SnapCandidatePoint const &p,
416 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
417 SPPath const *selected_path) const
418 {
419 _collectPaths(p, p.getSourceNum() == 0);
420 // Now we can finally do the real snapping, using the paths collected above
422 g_assert(_snapmanager->getDesktop() != NULL);
423 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p.getPoint());
425 bool const node_tool_active = _snapmanager->snapprefs.getSnapToItemPath() && selected_path != NULL;
427 if (p.getSourceNum() == 0) {
428 /* findCandidates() is used for snapping to both paths and nodes. It ignores the path that is
429 * currently being edited, because that path requires special care: when snapping to nodes
430 * only the unselected nodes of that path should be considered, and these will be passed on separately.
431 * This path must not be ignored however when snapping to the paths, so we add it here
432 * manually when applicable.
433 * */
434 if (node_tool_active) {
435 SPCurve *curve = curve_for_item(SP_ITEM(selected_path));
436 if (curve) {
437 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
438 _paths_to_snap_to->push_back(Inkscape::SnapCandidatePath(pathv, SNAPTARGET_PATH, Geom::OptRect(), true));
439 curve->unref();
440 }
441 }
442 }
444 for (std::vector<Inkscape::SnapCandidatePath >::const_iterator it_p = _paths_to_snap_to->begin(); it_p != _paths_to_snap_to->end(); it_p++) {
445 bool const being_edited = node_tool_active && (*it_p).currently_being_edited;
446 //if true then this pathvector it_pv is currently being edited in the node tool
448 for(Geom::PathVector::iterator it_pv = (it_p->path_vector)->begin(); it_pv != (it_p->path_vector)->end(); ++it_pv) {
449 // Find a nearest point for each curve within this path
450 // n curves will return n time values with 0 <= t <= 1
451 std::vector<double> anp = (*it_pv).nearestPointPerCurve(p_doc);
453 std::vector<double>::const_iterator np = anp.begin();
454 unsigned int index = 0;
455 for (; np != anp.end(); np++, index++) {
456 Geom::Curve const *curve = &((*it_pv).at_index(index));
457 Geom::Point const sp_doc = curve->pointAt(*np);
459 bool c1 = true;
460 bool c2 = true;
461 if (being_edited) {
462 /* If the path is being edited, then we should only snap though to stationary pieces of the path
463 * and not to the pieces that are being dragged around. This way we avoid
464 * self-snapping. For this we check whether the nodes at both ends of the current
465 * piece are unselected; if they are then this piece must be stationary
466 */
467 g_assert(unselected_nodes != NULL);
468 Geom::Point start_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(0));
469 Geom::Point end_pt = _snapmanager->getDesktop()->doc2dt(curve->pointAt(1));
470 c1 = isUnselectedNode(start_pt, unselected_nodes);
471 c2 = isUnselectedNode(end_pt, unselected_nodes);
472 /* Unfortunately, this might yield false positives for coincident nodes. Inkscape might therefore mistakenly
473 * snap to path segments that are not stationary. There are at least two possible ways to overcome this:
474 * - Linking the individual nodes of the SPPath we have here, to the nodes of the NodePath::SubPath class as being
475 * used in sp_nodepath_selected_nodes_move. This class has a member variable called "selected". For this the nodes
476 * should be in the exact same order for both classes, so we can index them
477 * - Replacing the SPPath being used here by the the NodePath::SubPath class; but how?
478 */
479 }
481 Geom::Point const sp_dt = _snapmanager->getDesktop()->doc2dt(sp_doc);
482 if (!being_edited || (c1 && c2)) {
483 Geom::Coord const dist = Geom::distance(sp_doc, p_doc);
484 if (dist < getSnapperTolerance()) {
485 sc.curves.push_back(Inkscape::SnappedCurve(sp_dt, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), false, curve, p.getSourceType(), p.getSourceNum(), it_p->target_type, it_p->target_bbox));
486 }
487 }
488 }
489 } // End of: for (Geom::PathVector::iterator ....)
490 }
491 }
493 /* Returns true if point is coincident with one of the unselected nodes */
494 bool Inkscape::ObjectSnapper::isUnselectedNode(Geom::Point const &point, std::vector<Inkscape::SnapCandidatePoint> const *unselected_nodes) const
495 {
496 if (unselected_nodes == NULL) {
497 return false;
498 }
500 if (unselected_nodes->size() == 0) {
501 return false;
502 }
504 for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = unselected_nodes->begin(); i != unselected_nodes->end(); i++) {
505 if (Geom::L2(point - (*i).getPoint()) < 1e-4) {
506 return true;
507 }
508 }
510 return false;
511 }
513 void Inkscape::ObjectSnapper::_snapPathsConstrained(SnappedConstraints &sc,
514 Inkscape::SnapCandidatePoint const &p,
515 ConstraintLine const &c) const
516 {
518 _collectPaths(p, p.getSourceNum() == 0);
520 // Now we can finally do the real snapping, using the paths collected above
522 g_assert(_snapmanager->getDesktop() != NULL);
523 Geom::Point const p_doc = _snapmanager->getDesktop()->dt2doc(p.getPoint());
525 Geom::Point direction_vector = c.getDirection();
526 if (!is_zero(direction_vector)) {
527 direction_vector = Geom::unit_vector(direction_vector);
528 }
530 // The intersection point of the constraint line with any path,
531 // must lie within two points on the constraintline: p_min_on_cl and p_max_on_cl
532 // The distance between those points is twice the snapping tolerance
533 Geom::Point const p_proj_on_cl = p.getPoint(); // projection has already been taken care of in constrainedSnap in the snapmanager;
534 Geom::Point const p_min_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl - getSnapperTolerance() * direction_vector);
535 Geom::Point const p_max_on_cl = _snapmanager->getDesktop()->dt2doc(p_proj_on_cl + getSnapperTolerance() * direction_vector);
537 Geom::Path cl;
538 std::vector<Geom::Path> clv;
539 cl.start(p_min_on_cl);
540 cl.appendNew<Geom::LineSegment>(p_max_on_cl);
541 clv.push_back(cl);
543 for (std::vector<Inkscape::SnapCandidatePath >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
544 if (k->path_vector) {
545 Geom::CrossingSet cs = Geom::crossings(clv, *(k->path_vector));
546 if (cs.size() > 0) {
547 // We need only the first element of cs, because cl is only a single straight linesegment
548 // This first element contains a vector filled with crossings of cl with k->first
549 for (std::vector<Geom::Crossing>::const_iterator m = cs[0].begin(); m != cs[0].end(); m++) {
550 if ((*m).ta >= 0 && (*m).ta <= 1 ) {
551 // Reconstruct the point of intersection
552 Geom::Point p_inters = p_min_on_cl + ((*m).ta) * (p_max_on_cl - p_min_on_cl);
553 // When it's within snapping range, then return it
554 // (within snapping range == between p_min_on_cl and p_max_on_cl == 0 < ta < 1)
555 Geom::Coord dist = Geom::L2(_snapmanager->getDesktop()->dt2doc(p_proj_on_cl) - p_inters);
556 SnappedPoint s(_snapmanager->getDesktop()->doc2dt(p_inters), p.getSourceType(), p.getSourceNum(), k->target_type, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true, k->target_bbox);
557 sc.points.push_back(s);
558 }
559 }
560 }
561 }
562 }
563 }
566 void Inkscape::ObjectSnapper::freeSnap(SnappedConstraints &sc,
567 Inkscape::SnapCandidatePoint const &p,
568 Geom::OptRect const &bbox_to_snap,
569 std::vector<SPItem const *> const *it,
570 std::vector<SnapCandidatePoint> *unselected_nodes) const
571 {
572 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(p.getSourceType()) == false ) {
573 return;
574 }
576 /* Get a list of all the SPItems that we will try to snap to */
577 if (p.getSourceNum() == 0) {
578 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p.getPoint(), p.getPoint());
579 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, p.getSourceNum() == 0, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
580 }
582 if (_snapmanager->snapprefs.getSnapToItemNode() || _snapmanager->snapprefs.getSnapSmoothNodes()
583 || _snapmanager->snapprefs.getSnapToBBoxNode() || _snapmanager->snapprefs.getSnapToPageBorder()
584 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
585 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
586 || _snapmanager->snapprefs.getIncludeItemCenter()) {
587 _snapNodes(sc, p, unselected_nodes);
588 }
590 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
591 unsigned n = (unselected_nodes == NULL) ? 0 : unselected_nodes->size();
592 if (n > 0) {
593 /* While editing a path in the node tool, findCandidates must ignore that path because
594 * of the node snapping requirements (i.e. only unselected nodes must be snapable).
595 * That path must not be ignored however when snapping to the paths, so we add it here
596 * manually when applicable
597 */
598 SPPath *path = NULL;
599 if (it != NULL) {
600 if (it->size() == 1 && SP_IS_PATH(*it->begin())) {
601 path = SP_PATH(*it->begin());
602 } // else: *it->begin() might be a SPGroup, e.g. when editing a LPE of text that has been converted to a group of paths
603 // as reported in bug #356743. In that case we can just ignore it, i.e. not snap to this item
604 }
605 _snapPaths(sc, p, unselected_nodes, path);
606 } else {
607 _snapPaths(sc, p, NULL, NULL);
608 }
609 }
610 }
612 void Inkscape::ObjectSnapper::constrainedSnap( SnappedConstraints &sc,
613 Inkscape::SnapCandidatePoint const &p,
614 Geom::OptRect const &bbox_to_snap,
615 ConstraintLine const &c,
616 std::vector<SPItem const *> const *it) const
617 {
618 if (_snap_enabled == false || _snapmanager->snapprefs.getSnapFrom(p.getSourceType()) == false) {
619 return;
620 }
622 /* Get a list of all the SPItems that we will try to snap to */
623 if (p.getSourceNum() == 0) {
624 Geom::Rect const local_bbox_to_snap = bbox_to_snap ? *bbox_to_snap : Geom::Rect(p.getPoint(), p.getPoint());
625 _findCandidates(sp_document_root(_snapmanager->getDocument()), it, p.getSourceNum() == 0, local_bbox_to_snap, TRANSL_SNAP_XY, false, Geom::identity());
626 }
628 // A constrained snap, is a snap in only one degree of freedom (specified by the constraint line).
629 // This is useful for example when scaling an object while maintaining a fixed aspect ratio. It's
630 // nodes are only allowed to move in one direction (i.e. in one degree of freedom).
632 // When snapping to objects, we either snap to their nodes or their paths. It is however very
633 // unlikely that any node will be exactly at the constrained line, so for a constrained snap
634 // to objects we will only consider the object's paths. Beside, the nodes will be at these paths,
635 // so we will more or less snap to them anyhow.
637 if (_snapmanager->snapprefs.getSnapToItemPath() || _snapmanager->snapprefs.getSnapToBBoxPath() || _snapmanager->snapprefs.getSnapToPageBorder()) {
638 _snapPathsConstrained(sc, p, c);
639 }
640 }
643 // This method is used to snap a guide to nodes, while dragging the guide around
644 void Inkscape::ObjectSnapper::guideFreeSnap(SnappedConstraints &sc,
645 Geom::Point const &p,
646 Geom::Point const &guide_normal) const
647 {
648 /* Get a list of all the SPItems that we will try to snap to */
649 std::vector<SPItem*> cand;
650 std::vector<SPItem const *> const it; //just an empty list
652 DimensionToSnap snap_dim;
653 if (guide_normal == to_2geom(component_vectors[Geom::Y])) {
654 snap_dim = GUIDE_TRANSL_SNAP_Y;
655 } else if (guide_normal == to_2geom(component_vectors[Geom::X])) {
656 snap_dim = GUIDE_TRANSL_SNAP_X;
657 } else {
658 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
659 }
661 _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), snap_dim, false, Geom::identity());
662 _snapTranslatingGuideToNodes(sc, p, guide_normal);
664 }
666 // This method is used to snap the origin of a guide to nodes/paths, while dragging the origin along the guide
667 void Inkscape::ObjectSnapper::guideConstrainedSnap(SnappedConstraints &sc,
668 Geom::Point const &p,
669 Geom::Point const &guide_normal,
670 ConstraintLine const &/*c*/) const
671 {
672 /* Get a list of all the SPItems that we will try to snap to */
673 std::vector<SPItem*> cand;
674 std::vector<SPItem const *> const it; //just an empty list
676 DimensionToSnap snap_dim;
677 if (guide_normal == to_2geom(component_vectors[Geom::Y])) {
678 snap_dim = GUIDE_TRANSL_SNAP_Y;
679 } else if (guide_normal == to_2geom(component_vectors[Geom::X])) {
680 snap_dim = GUIDE_TRANSL_SNAP_X;
681 } else {
682 snap_dim = ANGLED_GUIDE_TRANSL_SNAP;
683 }
685 _findCandidates(sp_document_root(_snapmanager->getDocument()), &it, true, Geom::Rect(p, p), snap_dim, false, Geom::identity());
686 _snapTranslatingGuideToNodes(sc, p, guide_normal);
688 }
690 /**
691 * \return true if this Snapper will snap at least one kind of point.
692 */
693 bool Inkscape::ObjectSnapper::ThisSnapperMightSnap() const
694 {
695 bool snap_to_something = _snapmanager->snapprefs.getSnapToItemPath()
696 || _snapmanager->snapprefs.getSnapToItemNode()
697 || _snapmanager->snapprefs.getSnapToBBoxPath()
698 || _snapmanager->snapprefs.getSnapToBBoxNode()
699 || _snapmanager->snapprefs.getSnapToPageBorder()
700 || _snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()
701 || _snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()
702 || _snapmanager->snapprefs.getIncludeItemCenter();
704 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeBBoxOrNodes() && snap_to_something);
705 }
707 bool Inkscape::ObjectSnapper::GuidesMightSnap() const // almost the same as ThisSnapperMightSnap above, but only looking at points (and not paths)
708 {
709 bool snap_to_something = _snapmanager->snapprefs.getSnapToItemNode()
710 || _snapmanager->snapprefs.getSnapToPageBorder()
711 || (_snapmanager->snapprefs.getSnapModeBBox() && _snapmanager->snapprefs.getSnapToBBoxNode())
712 || (_snapmanager->snapprefs.getSnapModeBBox() && (_snapmanager->snapprefs.getSnapBBoxEdgeMidpoints() || _snapmanager->snapprefs.getSnapBBoxMidpoints()))
713 || (_snapmanager->snapprefs.getSnapModeNode() && (_snapmanager->snapprefs.getSnapLineMidpoints() || _snapmanager->snapprefs.getSnapObjectMidpoints()))
714 || (_snapmanager->snapprefs.getSnapModeNode() && _snapmanager->snapprefs.getIncludeItemCenter())
715 || (_snapmanager->snapprefs.getSnapModeNode() && (_snapmanager->snapprefs.getSnapToItemPath() && _snapmanager->snapprefs.getSnapIntersectionCS()));
717 return (_snap_enabled && _snapmanager->snapprefs.getSnapModeGuide() && snap_to_something);
718 }
720 void Inkscape::ObjectSnapper::_clear_paths() const
721 {
722 for (std::vector<Inkscape::SnapCandidatePath >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); k++) {
723 delete k->path_vector;
724 }
725 _paths_to_snap_to->clear();
726 }
728 Geom::PathVector* Inkscape::ObjectSnapper::_getBorderPathv() const
729 {
730 Geom::Rect const border_rect = Geom::Rect(Geom::Point(0,0), Geom::Point(sp_document_width(_snapmanager->getDocument()),sp_document_height(_snapmanager->getDocument())));
731 return _getPathvFromRect(border_rect);
732 }
734 Geom::PathVector* Inkscape::ObjectSnapper::_getPathvFromRect(Geom::Rect const rect) const
735 {
736 SPCurve const *border_curve = SPCurve::new_from_rect(rect);
737 if (border_curve) {
738 Geom::PathVector *dummy = new Geom::PathVector(border_curve->get_pathvector());
739 return dummy;
740 } else {
741 return NULL;
742 }
743 }
745 void Inkscape::ObjectSnapper::_getBorderNodes(std::vector<SnapCandidatePoint> *points) const
746 {
747 Geom::Coord w = sp_document_width(_snapmanager->getDocument());
748 Geom::Coord h = sp_document_height(_snapmanager->getDocument());
749 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(0,0), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
750 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(0,h), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
751 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(w,h), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
752 points->push_back(Inkscape::SnapCandidatePoint(Geom::Point(w,0), SNAPSOURCE_UNDEFINED, SNAPTARGET_PAGE_CORNER));
753 }
755 void Inkscape::getBBoxPoints(Geom::OptRect const bbox,
756 std::vector<SnapCandidatePoint> *points,
757 bool const /*isTarget*/,
758 bool const includeCorners,
759 bool const includeLineMidpoints,
760 bool const includeObjectMidpoints)
761 {
762 if (bbox) {
763 // collect the corners of the bounding box
764 for ( unsigned k = 0 ; k < 4 ; k++ ) {
765 if (includeCorners) {
766 points->push_back(Inkscape::SnapCandidatePoint(bbox->corner(k), Inkscape::SNAPSOURCE_BBOX_CORNER, 0, Inkscape::SNAPTARGET_BBOX_CORNER, *bbox));
767 }
768 // optionally, collect the midpoints of the bounding box's edges too
769 if (includeLineMidpoints) {
770 points->push_back(Inkscape::SnapCandidatePoint((bbox->corner(k) + bbox->corner((k+1) % 4))/2, Inkscape::SNAPSOURCE_BBOX_EDGE_MIDPOINT, 0, Inkscape::SNAPTARGET_BBOX_EDGE_MIDPOINT, *bbox));
771 }
772 }
773 if (includeObjectMidpoints) {
774 points->push_back(Inkscape::SnapCandidatePoint(bbox->midpoint(), Inkscape::SNAPSOURCE_BBOX_MIDPOINT, 0, Inkscape::SNAPTARGET_BBOX_MIDPOINT, *bbox));
775 }
776 }
777 }
779 /*
780 Local Variables:
781 mode:c++
782 c-file-style:"stroustrup"
783 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
784 indent-tabs-mode:nil
785 fill-column:99
786 End:
787 */
788 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :