46b9ecad297e4c3154ff6dca23cb6a4256b22e2a
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 void SnapManager::freeSnapReturnByRef(Inkscape::Snapper::PointType point_type,
183 NR::Point &p,
184 bool first_point,
185 boost::optional<NR::Rect> const &bbox_to_snap) const
186 {
187 Inkscape::SnappedPoint const s = freeSnap(point_type, p, first_point, bbox_to_snap);
188 s.getPoint(p);
189 }
191 /**
192 * Try to snap a point to any of the specified snappers.
193 *
194 * \param point_type Type of point.
195 * \param p Point.
196 * \param first_point If true then this point is the first one from a whole bunch of points
197 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
198 * \param snappers List of snappers to try to snap to
199 * \return Snapped point.
200 */
202 Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::Snapper::PointType point_type,
203 NR::Point const &p,
204 bool first_point,
205 boost::optional<NR::Rect> const &bbox_to_snap) const
206 {
207 if (!SomeSnapperMightSnap()) {
208 return Inkscape::SnappedPoint(p, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false);
209 }
211 std::vector<SPItem const *> *items_to_ignore;
212 if (_item_to_ignore) { // If we have only a single item to ignore
213 // then build a list containing this single item;
214 // This single-item list will prevail over any other _items_to_ignore list, should that exist
215 items_to_ignore = new std::vector<SPItem const *>;
216 items_to_ignore->push_back(_item_to_ignore);
217 } else {
218 items_to_ignore = _items_to_ignore;
219 }
221 SnappedConstraints sc;
222 SnapperList const snappers = getSnappers();
224 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
225 (*i)->freeSnap(sc, point_type, p, first_point, bbox_to_snap, items_to_ignore, _unselected_nodes);
226 }
228 if (_item_to_ignore) {
229 delete items_to_ignore;
230 }
232 return findBestSnap(p, sc, false);
233 }
235 // When pasting, we would like to snap to the grid. Problem is that we don't know which nodes were
236 // aligned to the grid at the time of copying, so we don't know which nodes to snap. If we'd snap an
237 // unaligned node to the grid, previously aligned nodes would become unaligned. That's undesirable.
238 // Instead we will make sure that the offset between the source and the copy is a multiple of the grid
239 // pitch. If the source was aligned, then the copy will therefore also be aligned
240 // PS: Wether we really find a multiple also depends on the snapping range!
241 Geom::Point SnapManager::multipleOfGridPitch(Geom::Point const &t) const
242 {
243 if (!_snap_enabled_globally)
244 return t;
246 //FIXME: this code should actually do this: add new grid snappers that are active for this desktop. now it just adds all gridsnappers
247 SPDesktop* desktop = SP_ACTIVE_DESKTOP;
249 if (desktop && desktop->gridsEnabled()) {
250 bool success = false;
251 NR::Point nearest_multiple;
252 NR::Coord nearest_distance = NR_HUGE;
254 // It will snap to the grid for which we find the closest snap. This might be a different
255 // grid than to which the objects were initially aligned. I don't see an easy way to fix
256 // this, so when using multiple grids one can get unexpected results
258 // Cannot use getGridSnappers() because we need both the grids AND their snappers
259 // Therefor we iterate through all grids manually
260 for (GSList const *l = _named_view->grids; l != NULL; l = l->next) {
261 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
262 const Inkscape::Snapper* snapper = grid->snapper;
263 if (snapper && snapper->ThisSnapperMightSnap()) {
264 // To find the nearest multiple of the grid pitch for a given translation t, we
265 // will use the grid snapper. Simply snapping the value t to the grid will do, but
266 // only if the origin of the grid is at (0,0). If it's not then compensate for this
267 // in the translation t
268 NR::Point const t_offset = from_2geom(t) + grid->origin;
269 SnappedConstraints sc;
270 // Only the first three parameters are being used for grid snappers
271 snapper->freeSnap(sc, Inkscape::Snapper::SNAPPOINT_NODE, t_offset, TRUE, boost::optional<NR::Rect>(), NULL, NULL);
272 // Find the best snap for this grid, including intersections of the grid-lines
273 Inkscape::SnappedPoint s = findBestSnap(t_offset, sc, false);
274 if (s.getSnapped() && (s.getDistance() < nearest_distance)) {
275 success = true;
276 nearest_multiple = s.getPoint() - grid->origin;
277 nearest_distance = s.getDistance();
278 }
279 }
280 }
282 if (success)
283 return to_2geom(nearest_multiple);
284 }
286 return t;
287 }
289 /**
290 * Try to snap a point to any interested snappers. A snap will only occur along
291 * a line described by a Inkscape::Snapper::ConstraintLine.
292 *
293 * \param point_type Type of point.
294 * \param p Point.
295 * \param first_point If true then this point is the first one from a whole bunch of points
296 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
297 * \param constraint Constraint line.
298 * \return Snapped point.
299 */
301 void SnapManager::constrainedSnapReturnByRef(Inkscape::Snapper::PointType point_type,
302 NR::Point &p,
303 Inkscape::Snapper::ConstraintLine const &constraint,
304 bool first_point,
305 boost::optional<NR::Rect> const &bbox_to_snap) const
306 {
307 Inkscape::SnappedPoint const s = constrainedSnap(point_type, p, constraint, first_point, bbox_to_snap);
308 s.getPoint(p);
309 }
311 /**
312 * Try to snap a point to any interested snappers. A snap will only occur along
313 * a line described by a Inkscape::Snapper::ConstraintLine.
314 *
315 * \param point_type Type of point.
316 * \param p Point.
317 * \param first_point If true then this point is the first one from a whole bunch of points
318 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
319 * \param constraint Constraint line.
320 * \return Snapped point.
321 */
323 Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::Snapper::PointType point_type,
324 NR::Point const &p,
325 Inkscape::Snapper::ConstraintLine const &constraint,
326 bool first_point,
327 boost::optional<NR::Rect> const &bbox_to_snap) const
328 {
329 if (!SomeSnapperMightSnap()) {
330 return Inkscape::SnappedPoint(p, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false);
331 }
333 std::vector<SPItem const *> *items_to_ignore;
334 if (_item_to_ignore) { // If we have only a single item to ignore
335 // then build a list containing this single item;
336 // This single-item list will prevail over any other _items_to_ignore list, should that exist
337 items_to_ignore = new std::vector<SPItem const *>;
338 items_to_ignore->push_back(_item_to_ignore);
339 } else {
340 items_to_ignore = _items_to_ignore;
341 }
343 SnappedConstraints sc;
344 SnapperList const snappers = getSnappers();
345 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
346 (*i)->constrainedSnap(sc, point_type, p, first_point, bbox_to_snap, constraint, items_to_ignore);
347 }
349 if (_item_to_ignore) {
350 delete items_to_ignore;
351 }
353 return findBestSnap(p, sc, true);
354 }
356 void SnapManager::guideSnap(NR::Point &p, NR::Point const &guide_normal) const
357 {
358 // This method is used to snap a guide to nodes, while dragging the guide around
360 if (!(object.GuidesMightSnap() && _snap_enabled_globally)) {
361 return;
362 }
364 SnappedConstraints sc;
365 object.guideSnap(sc, p, guide_normal);
367 Inkscape::SnappedPoint const s = findBestSnap(p, sc, false);
368 s.getPoint(p);
369 }
372 /**
373 * Main internal snapping method, which is called by the other, friendlier, public
374 * methods. It's a bit hairy as it has lots of parameters, but it saves on a lot
375 * of duplicated code.
376 *
377 * \param type Type of points being snapped.
378 * \param points List of points to snap.
379 * \param constrained true if the snap is constrained.
380 * \param constraint Constraint line to use, if `constrained' is true, otherwise undefined.
381 * \param transformation_type Type of transformation to apply to points before trying to snap them.
382 * \param transformation Description of the transformation; details depend on the type.
383 * \param origin Origin of the transformation, if applicable.
384 * \param dim Dimension of the transformation, if applicable.
385 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
386 */
388 Inkscape::SnappedPoint SnapManager::_snapTransformed(
389 Inkscape::Snapper::PointType type,
390 std::vector<NR::Point> const &points,
391 bool constrained,
392 Inkscape::Snapper::ConstraintLine const &constraint,
393 Transformation transformation_type,
394 NR::Point const &transformation,
395 NR::Point const &origin,
396 NR::Dim2 dim,
397 bool uniform) const
398 {
399 /* We have a list of points, which we are proposing to transform in some way. We need to see
400 ** if any of these points, when transformed, snap to anything. If they do, we return the
401 ** appropriate transformation with `true'; otherwise we return the original scale with `false'.
402 */
404 /* Quick check to see if we have any snappers that are enabled
405 ** Also used to globally disable all snapping
406 */
407 if (SomeSnapperMightSnap() == false) {
408 g_assert(points.size() > 0);
409 return Inkscape::SnappedPoint();
410 }
412 std::vector<NR::Point> transformed_points;
413 NR::Rect bbox;
415 for (std::vector<NR::Point>::const_iterator i = points.begin(); i != points.end(); i++) {
417 /* Work out the transformed version of this point */
418 NR::Point transformed;
419 switch (transformation_type) {
420 case TRANSLATION:
421 transformed = *i + transformation;
422 break;
423 case SCALE:
424 transformed = (*i - origin) * NR::scale(transformation[NR::X], transformation[NR::Y]) + origin;
425 break;
426 case STRETCH:
427 {
428 NR::scale s(1, 1);
429 if (uniform)
430 s[NR::X] = s[NR::Y] = transformation[dim];
431 else {
432 s[dim] = transformation[dim];
433 s[1 - dim] = 1;
434 }
435 transformed = ((*i - origin) * s) + origin;
436 break;
437 }
438 case SKEW:
439 // Apply the skew factor
440 transformed[dim] = (*i)[dim] + transformation[0] * ((*i)[1 - dim] - origin[1 - dim]);
441 // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
442 // Apply that scale factor here
443 transformed[1-dim] = (*i - origin)[1 - dim] * transformation[1] + origin[1 - dim];
444 break;
445 default:
446 g_assert_not_reached();
447 }
449 // add the current transformed point to the box hulling all transformed points
450 if (i == points.begin()) {
451 bbox = NR::Rect(transformed, transformed);
452 } else {
453 bbox.expandTo(transformed);
454 }
456 transformed_points.push_back(transformed);
457 }
459 /* The current best transformation */
460 NR::Point best_transformation = transformation;
462 /* The current best metric for the best transformation; lower is better, NR_HUGE
463 ** means that we haven't snapped anything.
464 */
465 NR::Coord best_metric = NR_HUGE;
466 NR::Coord best_second_metric = NR_HUGE;
467 NR::Point best_scale_metric(NR_HUGE, NR_HUGE);
468 Inkscape::SnappedPoint best_snapped_point;
469 g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point
470 g_assert(best_snapped_point.getAtIntersection() == false);
472 std::vector<NR::Point>::const_iterator j = transformed_points.begin();
474 // std::cout << std::endl;
475 for (std::vector<NR::Point>::const_iterator i = points.begin(); i != points.end(); i++) {
477 /* Snap it */
478 Inkscape::SnappedPoint snapped_point;
480 if (constrained) {
481 Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint;
482 if ((transformation_type == SCALE || transformation_type == STRETCH) && uniform) {
483 // When uniformly scaling, each point will have its own unique constraint line,
484 // running from the scaling origin to the original untransformed point. We will
485 // calculate that line here
486 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, (*i) - origin);
487 } else if (transformation_type == STRETCH) { // when non-uniform stretching {
488 dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i), component_vectors[dim]);
489 } else if (transformation_type == TRANSLATION) {
490 // When doing a constrained translation, all points will move in the same direction, i.e.
491 // either horizontally or vertically. The lines along which they move are therefore all
492 // parallel, but might not be colinear. Therefore we will have to set the point through
493 // which the constraint-line runs here, for each point individually.
494 dedicated_constraint.setPoint(*i);
495 } // else: leave the original constraint, e.g. for skewing
496 if (transformation_type == SCALE && !uniform) {
497 g_warning("Non-uniform constrained scaling is not supported!");
498 }
499 snapped_point = constrainedSnap(type, *j, dedicated_constraint, i == points.begin(), bbox);
500 } else {
501 snapped_point = freeSnap(type, *j, i == points.begin(), bbox);
502 }
504 NR::Point result;
505 NR::Coord metric = NR_HUGE;
506 NR::Coord second_metric = NR_HUGE;
507 NR::Point scale_metric(NR_HUGE, NR_HUGE);
509 if (snapped_point.getSnapped()) {
510 /* We snapped. Find the transformation that describes where the snapped point has
511 ** ended up, and also the metric for this transformation.
512 */
513 NR::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point
514 NR::Point const b = (*i - origin); // vector to original point
516 switch (transformation_type) {
517 case TRANSLATION:
518 result = snapped_point.getPoint() - *i;
519 /* Consider the case in which a box is almost aligned with a grid in both
520 * horizontal and vertical directions. The distance to the intersection of
521 * the grid lines will always be larger then the distance to a single grid
522 * line. If we prefer snapping to an intersection instead of to a single
523 * grid line, then we cannot use "metric = NR::L2(result)". Therefore the
524 * snapped distance will be used as a metric. Please note that the snapped
525 * distance is defined as the distance to the nearest line of the intersection,
526 * and not to the intersection itself!
527 */
528 metric = snapped_point.getDistance(); //used to be: metric = NR::L2(result);
529 second_metric = snapped_point.getSecondDistance();
530 break;
531 case SCALE:
532 {
533 result = NR::Point(NR_HUGE, NR_HUGE);
534 // If this point *i is horizontally or vertically aligned with
535 // the origin of the scaling, then it will scale purely in X or Y
536 // We can therefore only calculate the scaling in this direction
537 // and the scaling factor for the other direction should remain
538 // untouched (unless scaling is uniform ofcourse)
539 for (int index = 0; index < 2; index++) {
540 if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
541 if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
542 result[index] = a[index] / b[index]; // then calculate it!
543 }
544 // we might leave result[1-index] = NR_HUGE
545 // if scaling didn't occur in the other direction
546 }
547 }
548 // Compare the resulting scaling with the desired scaling
549 scale_metric = result - transformation; // One or both of its components might be NR_HUGE
550 break;
551 }
552 case STRETCH:
553 result = NR::Point(NR_HUGE, NR_HUGE);
554 if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
555 result[dim] = a[dim] / b[dim];
556 result[1-dim] = uniform ? result[dim] : 1;
557 } else { // STRETCHING might occur for this point, but only when the stretching is uniform
558 if (uniform && fabs(b[1-dim]) > 1e-6) {
559 result[1-dim] = a[1-dim] / b[1-dim];
560 result[dim] = result[1-dim];
561 }
562 }
563 metric = std::abs(result[dim] - transformation[dim]);
564 break;
565 case SKEW:
566 result[0] = (snapped_point.getPoint()[dim] - (*i)[dim]) / ((*i)[1 - dim] - origin[1 - dim]); // skew factor
567 result[1] = transformation[1]; // scale factor
568 metric = std::abs(result[0] - transformation[0]);
569 break;
570 default:
571 g_assert_not_reached();
572 }
574 /* Note it if it's the best so far */
575 if (transformation_type == SCALE) {
576 for (int index = 0; index < 2; index++) {
577 if (fabs(scale_metric[index]) < fabs(best_scale_metric[index])) {
578 best_transformation[index] = result[index];
579 best_scale_metric[index] = fabs(scale_metric[index]);
580 // When scaling, we're considering the best transformation in each direction separately
581 // Therefore two different snapped points might together make a single best transformation
582 // We will however return only a single snapped point (e.g. to display the snapping indicator)
583 best_snapped_point = snapped_point;
584 // std::cout << "SEL ";
585 } // else { std::cout << " ";}
586 }
587 if (uniform) {
588 if (best_scale_metric[0] < best_scale_metric[1]) {
589 best_transformation[1] = best_transformation[0];
590 best_scale_metric[1] = best_scale_metric[0];
591 } else {
592 best_transformation[0] = best_transformation[1];
593 best_scale_metric[0] = best_scale_metric[1];
594 }
595 }
596 best_metric = std::min(best_scale_metric[0], best_scale_metric[1]);
597 // std::cout << "P_orig = " << (*i) << " | scale_metric = " << scale_metric << " | distance = " << snapped_point.getDistance() << " | P_snap = " << snapped_point.getPoint() << std::endl;
598 } else {
599 bool const c1 = metric < best_metric;
600 bool const c2 = metric == best_metric && snapped_point.getAtIntersection() == true && best_snapped_point.getAtIntersection() == false;
601 bool const c3a = metric == best_metric && snapped_point.getAtIntersection() == true && best_snapped_point.getAtIntersection() == true;
602 bool const c3b = second_metric < best_second_metric;
603 bool const c4 = snapped_point.getAlwaysSnap() == true && best_snapped_point.getAlwaysSnap() == false;
604 bool const c4n = snapped_point.getAlwaysSnap() == false && best_snapped_point.getAlwaysSnap() == true;
606 if ((c1 || c2 || (c3a && c3b) || c4) && !c4n) {
607 best_transformation = result;
608 best_metric = metric;
609 best_second_metric = second_metric;
610 best_snapped_point = snapped_point;
611 // std::cout << "SEL ";
612 } // else { std::cout << " ";}
613 // std::cout << "P_orig = " << (*i) << " | metric = " << metric << " | distance = " << snapped_point.getDistance() << " | second metric = " << second_metric << " | P_snap = " << snapped_point.getPoint() << std::endl;
614 }
615 }
617 j++;
618 }
620 if (transformation_type == SCALE) {
621 // When scaling, don't ever exit with one of scaling components set to NR_HUGE
622 for (int index = 0; index < 2; index++) {
623 if (best_transformation[index] == NR_HUGE) {
624 if (uniform && best_transformation[1-index] < NR_HUGE) {
625 best_transformation[index] = best_transformation[1-index];
626 } else {
627 best_transformation[index] = transformation[index];
628 }
629 }
630 }
631 }
633 best_snapped_point.setTransformation(best_transformation);
634 // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
635 // These rounding errors might be caused by NRRects, see bug #1584301
636 best_snapped_point.setDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
637 return best_snapped_point;
638 }
641 /**
642 * Try to snap a list of points to any interested snappers after they have undergone
643 * a translation.
644 *
645 * \param point_type Type of points.
646 * \param p Points.
647 * \param tr Proposed translation.
648 * \return Snapped translation, if a snap occurred, and a flag indicating whether a snap occurred.
649 */
651 Inkscape::SnappedPoint SnapManager::freeSnapTranslation(Inkscape::Snapper::PointType point_type,
652 std::vector<NR::Point> const &p,
653 NR::Point const &tr) const
654 {
655 return _snapTransformed(point_type, p, false, NR::Point(), TRANSLATION, tr, NR::Point(), NR::X, false);
656 }
659 /**
660 * Try to snap a list of points to any interested snappers after they have undergone a
661 * translation. A snap will only occur along a line described by a
662 * Inkscape::Snapper::ConstraintLine.
663 *
664 * \param point_type Type of points.
665 * \param p Points.
666 * \param constraint Constraint line.
667 * \param tr Proposed translation.
668 * \return Snapped translation, if a snap occurred, and a flag indicating whether a snap occurred.
669 */
671 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslation(Inkscape::Snapper::PointType point_type,
672 std::vector<NR::Point> const &p,
673 Inkscape::Snapper::ConstraintLine const &constraint,
674 NR::Point const &tr) const
675 {
676 return _snapTransformed(point_type, p, true, constraint, TRANSLATION, tr, NR::Point(), NR::X, false);
677 }
680 /**
681 * Try to snap a list of points to any interested snappers after they have undergone
682 * a scale.
683 *
684 * \param point_type Type of points.
685 * \param p Points.
686 * \param s Proposed scale.
687 * \param o Origin of proposed scale.
688 * \return Snapped scale, if a snap occurred, and a flag indicating whether a snap occurred.
689 */
691 Inkscape::SnappedPoint SnapManager::freeSnapScale(Inkscape::Snapper::PointType point_type,
692 std::vector<NR::Point> const &p,
693 NR::scale const &s,
694 NR::Point const &o) const
695 {
696 return _snapTransformed(point_type, p, false, NR::Point(), SCALE, NR::Point(s[NR::X], s[NR::Y]), o, NR::X, false);
697 }
700 /**
701 * Try to snap a list of points to any interested snappers after they have undergone
702 * a scale. A snap will only occur along a line described by a
703 * Inkscape::Snapper::ConstraintLine.
704 *
705 * \param point_type Type of points.
706 * \param p Points.
707 * \param s Proposed scale.
708 * \param o Origin of proposed scale.
709 * \return Snapped scale, if a snap occurred, and a flag indicating whether a snap occurred.
710 */
712 Inkscape::SnappedPoint SnapManager::constrainedSnapScale(Inkscape::Snapper::PointType point_type,
713 std::vector<NR::Point> const &p,
714 NR::scale const &s,
715 NR::Point const &o) const
716 {
717 // When constrained scaling, only uniform scaling is supported.
718 return _snapTransformed(point_type, p, true, NR::Point(), SCALE, NR::Point(s[NR::X], s[NR::Y]), o, NR::X, true);
719 }
722 /**
723 * Try to snap a list of points to any interested snappers after they have undergone
724 * a stretch.
725 *
726 * \param point_type Type of points.
727 * \param p Points.
728 * \param s Proposed stretch.
729 * \param o Origin of proposed stretch.
730 * \param d Dimension in which to apply proposed stretch.
731 * \param u true if the stretch should be uniform (ie to be applied equally in both dimensions)
732 * \return Snapped stretch, if a snap occurred, and a flag indicating whether a snap occurred.
733 */
735 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(Inkscape::Snapper::PointType point_type,
736 std::vector<NR::Point> const &p,
737 NR::Coord const &s,
738 NR::Point const &o,
739 NR::Dim2 d,
740 bool u) const
741 {
742 return _snapTransformed(point_type, p, true, NR::Point(), STRETCH, NR::Point(s, s), o, d, u);
743 }
746 /**
747 * Try to snap a list of points to any interested snappers after they have undergone
748 * a skew.
749 *
750 * \param point_type Type of points.
751 * \param p Points.
752 * \param s Proposed skew.
753 * \param o Origin of proposed skew.
754 * \param d Dimension in which to apply proposed skew.
755 * \return Snapped skew, if a snap occurred, and a flag indicating whether a snap occurred.
756 */
758 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(Inkscape::Snapper::PointType point_type,
759 std::vector<NR::Point> const &p,
760 Inkscape::Snapper::ConstraintLine const &constraint,
761 NR::Point const &s,
762 NR::Point const &o,
763 NR::Dim2 d) const
764 {
765 // "s" contains skew factor in s[0], and scale factor in s[1]
766 return _snapTransformed(point_type, p, true, constraint, SKEW, s, o, d, false);
767 }
769 Inkscape::SnappedPoint SnapManager::findBestSnap(NR::Point const &p, SnappedConstraints &sc, bool constrained) const
770 {
771 /*
772 std::cout << "Type and number of snapped constraints: " << std::endl;
773 std::cout << " Points : " << sc.points.size() << std::endl;
774 std::cout << " Lines : " << sc.lines.size() << std::endl;
775 std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
776 std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
777 */
779 // Store all snappoints
780 std::list<Inkscape::SnappedPoint> sp_list;
782 // search for the closest snapped point
783 Inkscape::SnappedPoint closestPoint;
784 if (getClosestSP(sc.points, closestPoint)) {
785 sp_list.push_back(closestPoint);
786 }
788 // search for the closest snapped line segment
789 Inkscape::SnappedLineSegment closestLineSegment;
790 if (getClosestSLS(sc.lines, closestLineSegment)) {
791 sp_list.push_back(Inkscape::SnappedPoint(closestLineSegment));
792 }
794 if (_intersectionLS) {
795 // search for the closest snapped intersection of line segments
796 Inkscape::SnappedPoint closestLineSegmentIntersection;
797 if (getClosestIntersectionSLS(sc.lines, closestLineSegmentIntersection)) {
798 sp_list.push_back(closestLineSegmentIntersection);
799 }
800 }
802 // search for the closest snapped grid line
803 Inkscape::SnappedLine closestGridLine;
804 if (getClosestSL(sc.grid_lines, closestGridLine)) {
805 closestGridLine.setTarget(Inkscape::SNAPTARGET_GRID);
806 sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
807 }
809 // search for the closest snapped guide line
810 Inkscape::SnappedLine closestGuideLine;
811 if (getClosestSL(sc.guide_lines, closestGuideLine)) {
812 closestGuideLine.setTarget(Inkscape::SNAPTARGET_GUIDE);
813 sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
814 }
816 // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
817 // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
819 // When doing a constrained snap however, we're already at an intersection of the constrained line and
820 // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
821 // no need to look for additional intersections
822 if (!constrained) {
823 // search for the closest snapped intersection of grid lines
824 Inkscape::SnappedPoint closestGridPoint;
825 if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
826 closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
827 sp_list.push_back(closestGridPoint);
828 }
830 // search for the closest snapped intersection of guide lines
831 Inkscape::SnappedPoint closestGuidePoint;
832 if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
833 closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
834 sp_list.push_back(closestGuidePoint);
835 }
837 // search for the closest snapped intersection of grid with guide lines
838 if (_intersectionGG) {
839 Inkscape::SnappedPoint closestGridGuidePoint;
840 if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
841 closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
842 sp_list.push_back(closestGridGuidePoint);
843 }
844 }
845 }
847 // now let's see which snapped point gets a thumbs up
848 Inkscape::SnappedPoint bestSnappedPoint = Inkscape::SnappedPoint(p, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false);
849 for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
850 // first find out if this snapped point is within snapping range
851 if ((*i).getDistance() <= (*i).getTolerance()) {
852 // if it's the first point
853 bool c1 = (i == sp_list.begin());
854 // or, if it's closer
855 bool c2 = (*i).getDistance() < bestSnappedPoint.getDistance();
856 // or, if it's for a snapper with "always snap" turned on, and the previous wasn't
857 bool c3 = (*i).getAlwaysSnap() && !bestSnappedPoint.getAlwaysSnap();
858 // But in no case fall back from a snapper with "always snap" on to one with "always snap" off
859 bool c3n = !(*i).getAlwaysSnap() && bestSnappedPoint.getAlwaysSnap();
860 // or, if it's just as close then consider the second distance
861 // (which is only relevant for points at an intersection)
862 bool c4a = ((*i).getDistance() == bestSnappedPoint.getDistance());
863 bool c4b = (*i).getSecondDistance() < bestSnappedPoint.getSecondDistance();
864 // then prefer this point over the previous one
865 if ((c1 || c2 || c3 || (c4a && c4b)) && !c3n) {
866 bestSnappedPoint = *i;
867 }
868 }
869 }
872 // Update the snap indicator, if requested
873 if (_desktop_for_snapindicator) {
874 if (bestSnappedPoint.getSnapped()) {
875 _desktop_for_snapindicator->snapindicator->set_new_snappoint(bestSnappedPoint);
876 } else {
877 _desktop_for_snapindicator->snapindicator->remove_snappoint();
878 }
879 }
881 // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << std::endl;
882 return bestSnappedPoint;
883 }
885 void SnapManager::setup(SPDesktop const *desktop_for_snapindicator, SPItem const *item_to_ignore, std::vector<NR::Point> *unselected_nodes)
886 {
887 _item_to_ignore = item_to_ignore;
888 _items_to_ignore = NULL;
889 _desktop_for_snapindicator = desktop_for_snapindicator;
890 _unselected_nodes = unselected_nodes;
891 }
893 void SnapManager::setup(SPDesktop const *desktop_for_snapindicator, std::vector<SPItem const *> &items_to_ignore, std::vector<NR::Point> *unselected_nodes)
894 {
895 _item_to_ignore = NULL;
896 _items_to_ignore = &items_to_ignore;
897 _desktop_for_snapindicator = desktop_for_snapindicator;
898 _unselected_nodes = unselected_nodes;
899 }
901 /*
902 Local Variables:
903 mode:c++
904 c-file-style:"stroustrup"
905 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
906 indent-tabs-mode:nil
907 fill-column:99
908 End:
909 */
910 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :