1 #define __SP_DESKTOP_SNAP_C__
3 /**
4 * \file snap.cpp
5 * \brief SnapManager class.
6 *
7 * Authors:
8 * Lauris Kaplinski <lauris@kaplinski.com>
9 * Frank Felfe <innerspace@iname.com>
10 * Nathan Hurst <njh@njhurst.com>
11 * Carl Hetherington <inkscape@carlh.net>
12 * Diederik van Lierop <mail@diedenrezi.nl>
13 *
14 * Copyright (C) 2006-2007 Johan Engelen <johan@shouraizou.nl>
15 * Copyrigth (C) 2004 Nathan Hurst
16 * Copyright (C) 1999-2008 Authors
17 *
18 * Released under GNU GPL, read the file 'COPYING' for more information
19 */
21 #include <utility>
23 #include "sp-namedview.h"
24 #include "snap.h"
25 #include "snapped-line.h"
27 #include <libnr/nr-point-fns.h>
28 #include <libnr/nr-scale-ops.h>
29 #include <libnr/nr-values.h>
31 #include "display/canvas-grid.h"
32 #include "display/snap-indicator.h"
34 #include "inkscape.h"
35 #include "desktop.h"
36 #include "sp-guide.h"
37 using std::vector;
39 /**
40 * Construct a SnapManager for a SPNamedView.
41 *
42 * \param v `Owning' SPNamedView.
43 */
45 SnapManager::SnapManager(SPNamedView const *v) :
46 guide(v, 0),
47 object(v, 0),
48 _named_view(v),
49 _include_item_center(false),
50 _snap_enabled_globally(true)
51 {
52 }
55 /**
56 * \return List of snappers that we use.
57 */
58 SnapManager::SnapperList
59 SnapManager::getSnappers() const
60 {
61 SnapManager::SnapperList s;
62 s.push_back(&guide);
63 s.push_back(&object);
65 SnapManager::SnapperList gs = getGridSnappers();
66 s.splice(s.begin(), gs);
68 return s;
69 }
71 /**
72 * \return List of gridsnappers that we use.
73 */
74 SnapManager::SnapperList
75 SnapManager::getGridSnappers() const
76 {
77 SnapperList s;
79 //FIXME: this code should actually do this: add new grid snappers that are active for this desktop. now it just adds all gridsnappers
80 SPDesktop* desktop = SP_ACTIVE_DESKTOP;
81 if (desktop && desktop->gridsEnabled()) {
82 for ( GSList const *l = _named_view->grids; l != NULL; l = l->next) {
83 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
84 s.push_back(grid->snapper);
85 }
86 }
88 return s;
89 }
91 /**
92 * \return true if one of the snappers will try to snap something.
93 */
95 bool SnapManager::SomeSnapperMightSnap() const
96 {
97 if (!_snap_enabled_globally) {
98 return false;
99 }
101 SnapperList const s = getSnappers();
102 SnapperList::const_iterator i = s.begin();
103 while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
104 i++;
105 }
107 return (i != s.end());
108 }
110 /*
111 * The snappers have too many parameters to adjust individually. Therefore only
112 * two snapping modes are presented to the user: snapping bounding box corners (to
113 * other bounding boxes, grids or guides), and/or snapping nodes (to other nodes,
114 * paths, grids or guides). To select either of these modes (or both), use the
115 * methods defined below: setSnapModeBBox() and setSnapModeNode().
116 *
117 * */
120 void SnapManager::setSnapModeBBox(bool enabled)
121 {
122 //The default values are being set in sp_namedview_set() (in sp-namedview.cpp)
123 guide.setSnapFrom(Inkscape::Snapper::SNAPPOINT_BBOX, enabled);
125 for ( GSList const *l = _named_view->grids; l != NULL; l = l->next) {
126 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
127 grid->snapper->setSnapFrom(Inkscape::Snapper::SNAPPOINT_BBOX, enabled);
128 }
130 object.setSnapFrom(Inkscape::Snapper::SNAPPOINT_BBOX, enabled);
131 //object.setSnapToBBoxNode(enabled); // On second thought, these should be controlled
132 //object.setSnapToBBoxPath(enabled); // separately by the snapping prefs dialog
133 object.setStrictSnapping(true); //don't snap bboxes to nodes/paths and vice versa
134 }
136 bool SnapManager::getSnapModeBBox() const
137 {
138 return guide.getSnapFrom(Inkscape::Snapper::SNAPPOINT_BBOX);
139 }
141 void SnapManager::setSnapModeNode(bool enabled)
142 {
143 guide.setSnapFrom(Inkscape::Snapper::SNAPPOINT_NODE, enabled);
145 for ( GSList const *l = _named_view->grids; l != NULL; l = l->next) {
146 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
147 grid->snapper->setSnapFrom(Inkscape::Snapper::SNAPPOINT_NODE, enabled);
148 }
150 object.setSnapFrom(Inkscape::Snapper::SNAPPOINT_NODE, enabled);
151 //object.setSnapToItemNode(enabled); // On second thought, these should be controlled
152 //object.setSnapToItemPath(enabled); // separately by the snapping prefs dialog
153 object.setStrictSnapping(true);
154 }
156 bool SnapManager::getSnapModeNode() const
157 {
158 return guide.getSnapFrom(Inkscape::Snapper::SNAPPOINT_NODE);
159 }
161 void SnapManager::setSnapModeGuide(bool enabled)
162 {
163 object.setSnapFrom(Inkscape::Snapper::SNAPPOINT_GUIDE, enabled);
164 }
166 bool SnapManager::getSnapModeGuide() const
167 {
168 return object.getSnapFrom(Inkscape::Snapper::SNAPPOINT_GUIDE);
169 }
171 /**
172 * Try to snap a point to any of the specified snappers.
173 *
174 * \param point_type Type of point.
175 * \param p Point.
176 * \param first_point If true then this point is the first one from a whole bunch of points
177 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
178 * \param snappers List of snappers to try to snap to
179 * \return Snapped point.
180 */
182 Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::Snapper::PointType point_type,
183 NR::Point const &p,
184 bool first_point,
185 NR::Maybe<NR::Rect> const &bbox_to_snap) const
186 {
187 if (!SomeSnapperMightSnap()) {
188 return Inkscape::SnappedPoint(p, NR_HUGE, 0, false);
189 }
191 std::vector<SPItem const *> *items_to_ignore;
192 if (_item_to_ignore) { // If we have only a single item to ignore
193 // then build a list containing this single item;
194 // This single-item list will prevail over any other _items_to_ignore list, should that exist
195 items_to_ignore = new std::vector<SPItem const *>;
196 items_to_ignore->push_back(_item_to_ignore);
197 } else {
198 items_to_ignore = _items_to_ignore;
199 }
201 SnappedConstraints sc;
202 SnapperList const snappers = getSnappers();
204 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
205 (*i)->freeSnap(sc, point_type, p, first_point, bbox_to_snap, items_to_ignore, _unselected_nodes);
206 }
208 if (_item_to_ignore) {
209 delete items_to_ignore;
210 }
212 return findBestSnap(p, sc, false);
213 }
215 /**
216 * Try to snap a point to any interested snappers. A snap will only occur along
217 * a line described by a Inkscape::Snapper::ConstraintLine.
218 *
219 * \param point_type Type of point.
220 * \param p Point.
221 * \param first_point If true then this point is the first one from a whole bunch of points
222 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
223 * \param constraint Constraint line.
224 * \return Snapped point.
225 */
227 Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::Snapper::PointType point_type,
228 NR::Point const &p,
229 Inkscape::Snapper::ConstraintLine const &constraint,
230 bool first_point,
231 NR::Maybe<NR::Rect> const &bbox_to_snap) const
232 {
233 if (!SomeSnapperMightSnap()) {
234 return Inkscape::SnappedPoint(p, NR_HUGE, 0, false);
235 }
237 std::vector<SPItem const *> *items_to_ignore;
238 if (_item_to_ignore) { // If we have only a single item to ignore
239 // then build a list containing this single item;
240 // This single-item list will prevail over any other _items_to_ignore list, should that exist
241 items_to_ignore = new std::vector<SPItem const *>;
242 items_to_ignore->push_back(_item_to_ignore);
243 } else {
244 items_to_ignore = _items_to_ignore;
245 }
247 SnappedConstraints sc;
248 SnapperList const snappers = getSnappers();
249 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
250 (*i)->constrainedSnap(sc, point_type, p, first_point, bbox_to_snap, constraint, items_to_ignore);
251 }
253 if (_item_to_ignore) {
254 delete items_to_ignore;
255 }
257 return findBestSnap(p, sc, true);
258 }
260 Inkscape::SnappedPoint SnapManager::guideSnap(NR::Point const &p,
261 NR::Point const &guide_normal) const
262 {
263 // This method is used to snap a guide to nodes, while dragging the guide around
265 if (!(object.GuidesMightSnap() && _snap_enabled_globally)) {
266 return Inkscape::SnappedPoint(p, NR_HUGE, 0, false);
267 }
269 SnappedConstraints sc;
270 object.guideSnap(sc, p, guide_normal);
272 return findBestSnap(p, sc, false);
273 }
276 /**
277 * Main internal snapping method, which is called by the other, friendlier, public
278 * methods. It's a bit hairy as it has lots of parameters, but it saves on a lot
279 * of duplicated code.
280 *
281 * \param type Type of points being snapped.
282 * \param points List of points to snap.
283 * \param constrained true if the snap is constrained.
284 * \param constraint Constraint line to use, if `constrained' is true, otherwise undefined.
285 * \param transformation_type Type of transformation to apply to points before trying to snap them.
286 * \param transformation Description of the transformation; details depend on the type.
287 * \param origin Origin of the transformation, if applicable.
288 * \param dim Dimension of the transformation, if applicable.
289 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
290 */
292 Inkscape::SnappedPoint SnapManager::_snapTransformed(
293 Inkscape::Snapper::PointType type,
294 std::vector<NR::Point> const &points,
295 bool constrained,
296 Inkscape::Snapper::ConstraintLine const &constraint,
297 Transformation transformation_type,
298 NR::Point const &transformation,
299 NR::Point const &origin,
300 NR::Dim2 dim,
301 bool uniform) const
302 {
303 /* We have a list of points, which we are proposing to transform in some way. We need to see
304 ** if any of these points, when transformed, snap to anything. If they do, we return the
305 ** appropriate transformation with `true'; otherwise we return the original scale with `false'.
306 */
308 /* Quick check to see if we have any snappers that are enabled
309 ** Also used to globally disable all snapping
310 */
311 if (SomeSnapperMightSnap() == false) {
312 return Inkscape::SnappedPoint();
313 }
315 std::vector<NR::Point> transformed_points;
316 NR::Rect bbox;
318 for (std::vector<NR::Point>::const_iterator i = points.begin(); i != points.end(); i++) {
320 /* Work out the transformed version of this point */
321 NR::Point transformed;
322 switch (transformation_type) {
323 case TRANSLATION:
324 transformed = *i + transformation;
325 break;
326 case SCALE:
327 transformed = (*i - origin) * NR::scale(transformation[NR::X], transformation[NR::Y]) + origin;
328 break;
329 case STRETCH:
330 {
331 NR::scale s(1, 1);
332 if (uniform)
333 s[NR::X] = s[NR::Y] = transformation[dim];
334 else {
335 s[dim] = transformation[dim];
336 s[1 - dim] = 1;
337 }
338 transformed = ((*i - origin) * s) + origin;
339 break;
340 }
341 case SKEW:
342 // Apply the skew factor
343 transformed[dim] = (*i)[dim] + transformation[0] * ((*i)[1 - dim] - origin[1 - dim]);
344 // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
345 // Apply that scale factor here
346 transformed[1-dim] = (*i - origin)[1 - dim] * transformation[1] + origin[1 - dim];
347 break;
348 default:
349 g_assert_not_reached();
350 }
352 // add the current transformed point to the box hulling all transformed points
353 if (i == points.begin()) {
354 bbox = NR::Rect(transformed, transformed);
355 } else {
356 bbox.expandTo(transformed);
357 }
359 transformed_points.push_back(transformed);
360 }
362 /* The current best transformation */
363 NR::Point best_transformation = transformation;
365 /* The current best metric for the best transformation; lower is better, NR_HUGE
366 ** means that we haven't snapped anything.
367 */
368 NR::Coord best_metric = NR_HUGE;
369 NR::Coord best_second_metric = NR_HUGE;
370 NR::Point best_scale_metric(NR_HUGE, NR_HUGE);
371 Inkscape::SnappedPoint best_snapped_point;
372 g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point
373 g_assert(best_snapped_point.getAtIntersection() == false);
375 std::vector<NR::Point>::const_iterator j = transformed_points.begin();
377 // std::cout << std::endl;
378 for (std::vector<NR::Point>::const_iterator i = points.begin(); i != points.end(); i++) {
380 /* Snap it */
381 Inkscape::SnappedPoint snapped_point;
383 if (constrained) {
384 Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint;
385 if ((transformation_type == SCALE || transformation_type == STRETCH) && uniform) {
386 // When uniformly scaling, each point will have its own unique constraint line,
387 // running from the scaling origin to the original untransformed point. We will
388 // calculate that line here
389 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, (*i) - origin);
390 } else if (transformation_type == STRETCH) { // when non-uniform stretching {
391 dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i), component_vectors[dim]);
392 } // else: leave the original constraint, e.g. for constrained translation and skewing
393 if (transformation_type == SCALE && !uniform) {
394 g_warning("Non-uniform constrained scaling is not supported!");
395 }
396 snapped_point = constrainedSnap(type, *j, dedicated_constraint, i == points.begin(), bbox);
397 } else {
398 snapped_point = freeSnap(type, *j, i == points.begin(), bbox);
399 }
401 NR::Point result;
402 NR::Coord metric = NR_HUGE;
403 NR::Coord second_metric = NR_HUGE;
404 NR::Point scale_metric(NR_HUGE, NR_HUGE);
406 if (snapped_point.getSnapped()) {
407 /* We snapped. Find the transformation that describes where the snapped point has
408 ** ended up, and also the metric for this transformation.
409 */
410 NR::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point
411 NR::Point const b = (*i - origin); // vector to original point
413 switch (transformation_type) {
414 case TRANSLATION:
415 result = snapped_point.getPoint() - *i;
416 /* Consider the case in which a box is almost aligned with a grid in both
417 * horizontal and vertical directions. The distance to the intersection of
418 * the grid lines will always be larger then the distance to a single grid
419 * line. If we prefer snapping to an intersection instead of to a single
420 * grid line, then we cannot use "metric = NR::L2(result)". Therefore the
421 * snapped distance will be used as a metric. Please note that the snapped
422 * distance is defined as the distance to the nearest line of the intersection,
423 * and not to the intersection itself!
424 */
425 metric = snapped_point.getDistance(); //used to be: metric = NR::L2(result);
426 second_metric = snapped_point.getSecondDistance();
427 break;
428 case SCALE:
429 {
430 result = NR::Point(NR_HUGE, NR_HUGE);
431 // If this point *i is horizontally or vertically aligned with
432 // the origin of the scaling, then it will scale purely in X or Y
433 // We can therefore only calculate the scaling in this direction
434 // and the scaling factor for the other direction should remain
435 // untouched (unless scaling is uniform ofcourse)
436 for (int index = 0; index < 2; index++) {
437 if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
438 if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
439 result[index] = a[index] / b[index]; // then calculate it!
440 }
441 // we might leave result[1-index] = NR_HUGE
442 // if scaling didn't occur in the other direction
443 }
444 }
445 // Compare the resulting scaling with the desired scaling
446 scale_metric = result - transformation; // One or both of its components might be NR_HUGE
447 break;
448 }
449 case STRETCH:
450 result = NR::Point(NR_HUGE, NR_HUGE);
451 if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
452 result[dim] = a[dim] / b[dim];
453 result[1-dim] = uniform ? result[dim] : 1;
454 } else { // STRETCHING might occur for this point, but only when the stretching is uniform
455 if (uniform && fabs(b[1-dim]) > 1e-6) {
456 result[1-dim] = a[1-dim] / b[1-dim];
457 result[dim] = result[1-dim];
458 }
459 }
460 metric = std::abs(result[dim] - transformation[dim]);
461 break;
462 case SKEW:
463 result[0] = (snapped_point.getPoint()[dim] - (*i)[dim]) / ((*i)[1 - dim] - origin[1 - dim]); // skew factor
464 result[1] = transformation[1]; // scale factor
465 metric = std::abs(result[0] - transformation[0]);
466 break;
467 default:
468 g_assert_not_reached();
469 }
471 /* Note it if it's the best so far */
472 if (transformation_type == SCALE) {
473 for (int index = 0; index < 2; index++) {
474 if (fabs(scale_metric[index]) < fabs(best_scale_metric[index])) {
475 best_transformation[index] = result[index];
476 best_scale_metric[index] = fabs(scale_metric[index]);
477 // When scaling, we're considering the best transformation in each direction separately
478 // Therefore two different snapped points might together make a single best transformation
479 // We will however return only a single snapped point (e.g. to display the snapping indicator)
480 best_snapped_point = snapped_point;
481 // std::cout << "SEL ";
482 } // else { std::cout << " ";}
483 }
484 if (uniform) {
485 if (best_scale_metric[0] < best_scale_metric[1]) {
486 best_transformation[1] = best_transformation[0];
487 best_scale_metric[1] = best_scale_metric[0];
488 } else {
489 best_transformation[0] = best_transformation[1];
490 best_scale_metric[0] = best_scale_metric[1];
491 }
492 }
493 best_metric = std::min(best_scale_metric[0], best_scale_metric[1]);
494 // std::cout << "P_orig = " << (*i) << " | scale_metric = " << scale_metric << " | distance = " << snapped_point.getDistance() << " | P_snap = " << snapped_point.getPoint() << std::endl;
495 } else {
496 bool const c1 = metric < best_metric;
497 bool const c2 = metric == best_metric && snapped_point.getAtIntersection() == true && best_snapped_point.getAtIntersection() == false;
498 bool const c3a = metric == best_metric && snapped_point.getAtIntersection() == true && best_snapped_point.getAtIntersection() == true;
499 bool const c3b = second_metric < best_second_metric;
500 bool const c4 = snapped_point.getAlwaysSnap() == true && best_snapped_point.getAlwaysSnap() == false;
501 bool const c4n = snapped_point.getAlwaysSnap() == false && best_snapped_point.getAlwaysSnap() == true;
503 if ((c1 || c2 || (c3a && c3b) || c4) && !c4n) {
504 best_transformation = result;
505 best_metric = metric;
506 best_second_metric = second_metric;
507 best_snapped_point = snapped_point;
508 // std::cout << "SEL ";
509 } // else { std::cout << " ";}
510 // std::cout << "P_orig = " << (*i) << " | metric = " << metric << " | distance = " << snapped_point.getDistance() << " | second metric = " << second_metric << " | P_snap = " << snapped_point.getPoint() << std::endl;
511 }
512 }
514 j++;
515 }
517 if (transformation_type == SCALE) {
518 // When scaling, don't ever exit with one of scaling components set to NR_HUGE
519 for (int index = 0; index < 2; index++) {
520 if (best_transformation[index] == NR_HUGE) {
521 if (uniform && best_transformation[1-index] < NR_HUGE) {
522 best_transformation[index] = best_transformation[1-index];
523 } else {
524 best_transformation[index] = transformation[index];
525 }
526 }
527 }
528 }
530 best_snapped_point.setTransformation(best_transformation);
531 // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
532 // These rounding errors might be caused by NRRects, see bug #1584301
533 best_snapped_point.setDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
534 return best_snapped_point;
535 }
538 /**
539 * Try to snap a list of points to any interested snappers after they have undergone
540 * a translation.
541 *
542 * \param point_type Type of points.
543 * \param p Points.
544 * \param tr Proposed translation.
545 * \return Snapped translation, if a snap occurred, and a flag indicating whether a snap occurred.
546 */
548 Inkscape::SnappedPoint SnapManager::freeSnapTranslation(Inkscape::Snapper::PointType point_type,
549 std::vector<NR::Point> const &p,
550 NR::Point const &tr) const
551 {
552 return _snapTransformed(point_type, p, false, NR::Point(), TRANSLATION, tr, NR::Point(), NR::X, false);
553 }
556 /**
557 * Try to snap a list of points to any interested snappers after they have undergone a
558 * translation. A snap will only occur along a line described by a
559 * Inkscape::Snapper::ConstraintLine.
560 *
561 * \param point_type Type of points.
562 * \param p Points.
563 * \param constraint Constraint line.
564 * \param tr Proposed translation.
565 * \return Snapped translation, if a snap occurred, and a flag indicating whether a snap occurred.
566 */
568 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslation(Inkscape::Snapper::PointType point_type,
569 std::vector<NR::Point> const &p,
570 Inkscape::Snapper::ConstraintLine const &constraint,
571 NR::Point const &tr) const
572 {
573 return _snapTransformed(point_type, p, true, constraint, TRANSLATION, tr, NR::Point(), NR::X, false);
574 }
577 /**
578 * Try to snap a list of points to any interested snappers after they have undergone
579 * a scale.
580 *
581 * \param point_type Type of points.
582 * \param p Points.
583 * \param s Proposed scale.
584 * \param o Origin of proposed scale.
585 * \return Snapped scale, if a snap occurred, and a flag indicating whether a snap occurred.
586 */
588 Inkscape::SnappedPoint SnapManager::freeSnapScale(Inkscape::Snapper::PointType point_type,
589 std::vector<NR::Point> const &p,
590 NR::scale const &s,
591 NR::Point const &o) const
592 {
593 return _snapTransformed(point_type, p, false, NR::Point(), SCALE, NR::Point(s[NR::X], s[NR::Y]), o, NR::X, false);
594 }
597 /**
598 * Try to snap a list of points to any interested snappers after they have undergone
599 * a scale. A snap will only occur along a line described by a
600 * Inkscape::Snapper::ConstraintLine.
601 *
602 * \param point_type Type of points.
603 * \param p Points.
604 * \param s Proposed scale.
605 * \param o Origin of proposed scale.
606 * \return Snapped scale, if a snap occurred, and a flag indicating whether a snap occurred.
607 */
609 Inkscape::SnappedPoint SnapManager::constrainedSnapScale(Inkscape::Snapper::PointType point_type,
610 std::vector<NR::Point> const &p,
611 NR::scale const &s,
612 NR::Point const &o) const
613 {
614 // When constrained scaling, only uniform scaling is supported.
615 return _snapTransformed(point_type, p, true, NR::Point(), SCALE, NR::Point(s[NR::X], s[NR::Y]), o, NR::X, true);
616 }
619 /**
620 * Try to snap a list of points to any interested snappers after they have undergone
621 * a stretch.
622 *
623 * \param point_type Type of points.
624 * \param p Points.
625 * \param s Proposed stretch.
626 * \param o Origin of proposed stretch.
627 * \param d Dimension in which to apply proposed stretch.
628 * \param u true if the stretch should be uniform (ie to be applied equally in both dimensions)
629 * \return Snapped stretch, if a snap occurred, and a flag indicating whether a snap occurred.
630 */
632 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(Inkscape::Snapper::PointType point_type,
633 std::vector<NR::Point> const &p,
634 NR::Coord const &s,
635 NR::Point const &o,
636 NR::Dim2 d,
637 bool u) const
638 {
639 return _snapTransformed(point_type, p, true, NR::Point(), STRETCH, NR::Point(s, s), o, d, u);
640 }
643 /**
644 * Try to snap a list of points to any interested snappers after they have undergone
645 * a skew.
646 *
647 * \param point_type Type of points.
648 * \param p Points.
649 * \param s Proposed skew.
650 * \param o Origin of proposed skew.
651 * \param d Dimension in which to apply proposed skew.
652 * \return Snapped skew, if a snap occurred, and a flag indicating whether a snap occurred.
653 */
655 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(Inkscape::Snapper::PointType point_type,
656 std::vector<NR::Point> const &p,
657 Inkscape::Snapper::ConstraintLine const &constraint,
658 NR::Point const &s,
659 NR::Point const &o,
660 NR::Dim2 d) const
661 {
662 // "s" contains skew factor in s[0], and scale factor in s[1]
663 return _snapTransformed(point_type, p, true, constraint, SKEW, s, o, d, false);
664 }
666 Inkscape::SnappedPoint SnapManager::findBestSnap(NR::Point const &p, SnappedConstraints &sc, bool constrained) const
667 {
668 /*
669 std::cout << "Type and number of snapped constraints: " << std::endl;
670 std::cout << " Points : " << sc.points.size() << std::endl;
671 std::cout << " Lines : " << sc.lines.size() << std::endl;
672 std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
673 std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
674 */
676 // Store all snappoints
677 std::list<Inkscape::SnappedPoint> sp_list;
679 // search for the closest snapped point
680 Inkscape::SnappedPoint closestPoint;
681 if (getClosestSP(sc.points, closestPoint)) {
682 sp_list.push_back(closestPoint);
683 }
685 // search for the closest snapped line segment
686 Inkscape::SnappedLineSegment closestLineSegment;
687 if (getClosestSLS(sc.lines, closestLineSegment)) {
688 sp_list.push_back(Inkscape::SnappedPoint(closestLineSegment));
689 }
691 if (_intersectionLS) {
692 // search for the closest snapped intersection of line segments
693 Inkscape::SnappedPoint closestLineSegmentIntersection;
694 if (getClosestIntersectionSLS(sc.lines, closestLineSegmentIntersection)) {
695 sp_list.push_back(closestLineSegmentIntersection);
696 }
697 }
699 // search for the closest snapped grid line
700 Inkscape::SnappedLine closestGridLine;
701 if (getClosestSL(sc.grid_lines, closestGridLine)) {
702 sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
703 }
705 // search for the closest snapped guide line
706 Inkscape::SnappedLine closestGuideLine;
707 if (getClosestSL(sc.guide_lines, closestGuideLine)) {
708 sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
709 }
711 // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
712 // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
714 // When doing a constrained snap however, we're already at an intersection of the constrained line and
715 // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
716 // no need to look for additional intersections
717 if (!constrained) {
718 // search for the closest snapped intersection of grid lines
719 Inkscape::SnappedPoint closestGridPoint;
720 if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
721 sp_list.push_back(closestGridPoint);
722 }
724 // search for the closest snapped intersection of guide lines
725 Inkscape::SnappedPoint closestGuidePoint;
726 if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
727 sp_list.push_back(closestGuidePoint);
728 }
730 // search for the closest snapped intersection of grid with guide lines
731 if (_intersectionGG) {
732 Inkscape::SnappedPoint closestGridGuidePoint;
733 if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
734 sp_list.push_back(closestGridGuidePoint);
735 }
736 }
737 }
739 // now let's see which snapped point gets a thumbs up
740 Inkscape::SnappedPoint bestSnappedPoint = Inkscape::SnappedPoint(p, NR_HUGE, 0, false);
741 for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
742 // first find out if this snapped point is within snapping range
743 if ((*i).getDistance() <= (*i).getTolerance()) {
744 // if it's the first point
745 bool c1 = (i == sp_list.begin());
746 // or, if it's closer
747 bool c2 = (*i).getDistance() < bestSnappedPoint.getDistance();
748 // or, if it's for a snapper with "always snap" turned on, and the previous wasn't
749 bool c3 = (*i).getAlwaysSnap() && !bestSnappedPoint.getAlwaysSnap();
750 // But in no case fall back from a snapper with "always snap" on to one with "always snap" off
751 bool c3n = !(*i).getAlwaysSnap() && bestSnappedPoint.getAlwaysSnap();
752 // or, if it's just as close then consider the second distance
753 // (which is only relevant for points at an intersection)
754 bool c4a = ((*i).getDistance() == bestSnappedPoint.getDistance());
755 bool c4b = (*i).getSecondDistance() < bestSnappedPoint.getSecondDistance();
756 // then prefer this point over the previous one
757 if ((c1 || c2 || c3 || (c4a && c4b)) && !c3n) {
758 bestSnappedPoint = *i;
759 }
760 }
761 }
764 // Update the snap indicator, if requested
765 if (_desktop_for_snapindicator) {
766 if (bestSnappedPoint.getSnapped()) {
767 _desktop_for_snapindicator->snapindicator->set_new_snappoint(bestSnappedPoint);
768 } else {
769 _desktop_for_snapindicator->snapindicator->remove_snappoint();
770 }
771 }
773 // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << std::endl;
774 return bestSnappedPoint;
775 }
777 void SnapManager::setup(SPDesktop const *desktop_for_snapindicator, SPItem const *item_to_ignore, std::vector<NR::Point> *unselected_nodes)
778 {
779 _item_to_ignore = item_to_ignore;
780 _items_to_ignore = NULL;
781 _desktop_for_snapindicator = desktop_for_snapindicator;
782 _unselected_nodes = unselected_nodes;
783 }
785 void SnapManager::setup(SPDesktop const *desktop_for_snapindicator, std::vector<SPItem const *> &items_to_ignore, std::vector<NR::Point> *unselected_nodes)
786 {
787 _item_to_ignore = NULL;
788 _items_to_ignore = &items_to_ignore;
789 _desktop_for_snapindicator = desktop_for_snapindicator;
790 _unselected_nodes = unselected_nodes;
791 }
793 /*
794 Local Variables:
795 mode:c++
796 c-file-style:"stroustrup"
797 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
798 indent-tabs-mode:nil
799 fill-column:99
800 End:
801 */
802 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :