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) 1999-2010 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"
26 #include "snapped-curve.h"
28 #include "display/canvas-grid.h"
29 #include "display/snap-indicator.h"
31 #include "inkscape.h"
32 #include "desktop.h"
33 #include "selection.h"
34 #include "sp-guide.h"
35 #include "preferences.h"
36 #include "event-context.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(this, 0),
47 object(this, 0),
48 snapprefs(),
49 _named_view(v)
50 {
51 }
53 /**
54 * \brief Return a list of snappers
55 *
56 * Inkscape snaps to objects, grids, and guides. For each of these snap targets a
57 * separate class is used, which has been derived from the base Snapper class. The
58 * getSnappers() method returns a list of pointers to instances of this class. This
59 * list contains exactly one instance of the guide snapper and of the object snapper
60 * class, but any number of grid snappers (because each grid has its own snapper
61 * instance)
62 *
63 * \return List of snappers that we use.
64 */
65 SnapManager::SnapperList
66 SnapManager::getSnappers() const
67 {
68 SnapManager::SnapperList s;
69 s.push_back(&guide);
70 s.push_back(&object);
72 SnapManager::SnapperList gs = getGridSnappers();
73 s.splice(s.begin(), gs);
75 return s;
76 }
78 /**
79 * \brief Return a list of gridsnappers
80 *
81 * Each grid has its own instance of the snapper class. This way snapping can
82 * be enabled per grid individually. A list will be returned containing the
83 * pointers to these instances, but only for grids that are being displayed
84 * and for which snapping is enabled.
85 *
86 * \return List of gridsnappers that we use.
87 */
88 SnapManager::SnapperList
89 SnapManager::getGridSnappers() const
90 {
91 SnapperList s;
93 if (_desktop && _desktop->gridsEnabled() && snapprefs.getSnapToGrids()) {
94 for ( GSList const *l = _named_view->grids; l != NULL; l = l->next) {
95 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
96 s.push_back(grid->snapper);
97 }
98 }
100 return s;
101 }
103 /**
104 * \brief Return true if any snapping might occur, whether its to grids, guides or objects
105 *
106 * Each snapper instance handles its own snapping target, e.g. grids, guides or
107 * objects. This method iterates through all these snapper instances and returns
108 * true if any of the snappers might possible snap, considering only the relevant
109 * snapping preferences.
110 *
111 * \return true if one of the snappers will try to snap to something.
112 */
114 bool SnapManager::someSnapperMightSnap() const
115 {
116 if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) {
117 return false;
118 }
120 SnapperList const s = getSnappers();
121 SnapperList::const_iterator i = s.begin();
122 while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
123 i++;
124 }
126 return (i != s.end());
127 }
129 /**
130 * \return true if one of the grids might be snapped to.
131 */
133 bool SnapManager::gridSnapperMightSnap() const
134 {
135 if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) {
136 return false;
137 }
139 SnapperList const s = getGridSnappers();
140 SnapperList::const_iterator i = s.begin();
141 while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
142 i++;
143 }
145 return (i != s.end());
146 }
148 /**
149 * \brief Try to snap a point to grids, guides or objects.
150 *
151 * Try to snap a point to grids, guides or objects, in two degrees-of-freedom,
152 * i.e. snap in any direction on the two dimensional canvas to the nearest
153 * snap target. freeSnapReturnByRef() is equal in snapping behavior to
154 * freeSnap(), but the former returns the snapped point trough the referenced
155 * parameter p. This parameter p initially contains the position of the snap
156 * source and will we overwritten by the target position if snapping has occurred.
157 * This makes snapping transparent to the calling code. If this is not desired
158 * because either the calling code must know whether snapping has occurred, or
159 * because the original position should not be touched, then freeSnap() should be
160 * called instead.
161 *
162 * PS:
163 * 1) SnapManager::setup() must have been called before calling this method,
164 * but only once for a set of points
165 * 2) Only to be used when a single source point is to be snapped; it assumes
166 * that source_num = 0, which is inefficient when snapping sets our source points
167 *
168 * \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred
169 * \param source_type Detailed description of the source type, will be used by the snap indicator
170 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
171 */
173 void SnapManager::freeSnapReturnByRef(Geom::Point &p,
174 Inkscape::SnapSourceType const source_type,
175 Geom::OptRect const &bbox_to_snap) const
176 {
177 Inkscape::SnappedPoint const s = freeSnap(Inkscape::SnapCandidatePoint(p, source_type), bbox_to_snap);
178 s.getPoint(p);
179 }
182 /**
183 * \brief Try to snap a point to grids, guides or objects.
184 *
185 * Try to snap a point to grids, guides or objects, in two degrees-of-freedom,
186 * i.e. snap in any direction on the two dimensional canvas to the nearest
187 * snap target. freeSnap() is equal in snapping behavior to
188 * freeSnapReturnByRef(). Please read the comments of the latter for more details
189 *
190 * PS: SnapManager::setup() must have been called before calling this method,
191 * but only once for a set of points
192 *
193 * \param p Source point to be snapped
194 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
195 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
196 */
199 Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::SnapCandidatePoint const &p,
200 Geom::OptRect const &bbox_to_snap) const
201 {
202 if (!someSnapperMightSnap()) {
203 return Inkscape::SnappedPoint(p, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false, false);
204 }
206 SnappedConstraints sc;
207 SnapperList const snappers = getSnappers();
209 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
210 (*i)->freeSnap(sc, p, bbox_to_snap, &_items_to_ignore, _unselected_nodes);
211 }
213 return findBestSnap(p, sc, false);
214 }
216 void SnapManager::preSnap(Inkscape::SnapCandidatePoint const &p)
217 {
218 // setup() must have been called before calling this method!
220 if (_snapindicator) {
221 _snapindicator = false; // prevent other methods from drawing a snap indicator; we want to control this here
222 Inkscape::SnappedPoint s = freeSnap(p);
223 if (s.getSnapped()) {
224 _desktop->snapindicator->set_new_snaptarget(s, true);
225 } else {
226 _desktop->snapindicator->remove_snaptarget(true);
227 }
228 _snapindicator = true; // restore the original value
229 }
230 }
232 /**
233 * \brief Snap to the closest multiple of a grid pitch
234 *
235 * When pasting, we would like to snap to the grid. Problem is that we don't know which
236 * nodes were aligned to the grid at the time of copying, so we don't know which nodes
237 * to snap. If we'd snap an unaligned node to the grid, previously aligned nodes would
238 * become unaligned. That's undesirable. Instead we will make sure that the offset
239 * between the source and its pasted copy is a multiple of the grid pitch. If the source
240 * was aligned, then the copy will therefore also be aligned.
241 *
242 * PS: Whether we really find a multiple also depends on the snapping range! Most users
243 * will have "always snap" enabled though, in which case a multiple will always be found.
244 * PS2: When multiple grids are present then the result will become ambiguous. There is no
245 * way to control to which grid this method will snap.
246 *
247 * \param t Vector that represents the offset of the pasted copy with respect to the original
248 * \return Offset vector after snapping to the closest multiple of a grid pitch
249 */
251 Geom::Point SnapManager::multipleOfGridPitch(Geom::Point const &t, Geom::Point const &origin)
252 {
253 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally())
254 return t;
256 if (_desktop && _desktop->gridsEnabled()) {
257 bool success = false;
258 Geom::Point nearest_multiple;
259 Geom::Coord nearest_distance = NR_HUGE;
260 Inkscape::SnappedPoint bestSnappedPoint(t);
262 // It will snap to the grid for which we find the closest snap. This might be a different
263 // grid than to which the objects were initially aligned. I don't see an easy way to fix
264 // this, so when using multiple grids one can get unexpected results
266 // Cannot use getGridSnappers() because we need both the grids AND their snappers
267 // Therefore we iterate through all grids manually
268 for (GSList const *l = _named_view->grids; l != NULL; l = l->next) {
269 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
270 const Inkscape::Snapper* snapper = grid->snapper;
271 if (snapper && snapper->ThisSnapperMightSnap()) {
272 // To find the nearest multiple of the grid pitch for a given translation t, we
273 // will use the grid snapper. Simply snapping the value t to the grid will do, but
274 // only if the origin of the grid is at (0,0). If it's not then compensate for this
275 // in the translation t
276 Geom::Point const t_offset = t + grid->origin;
277 SnappedConstraints sc;
278 // Only the first three parameters are being used for grid snappers
279 snapper->freeSnap(sc, Inkscape::SnapCandidatePoint(t_offset, Inkscape::SNAPSOURCE_GRID_PITCH),Geom::OptRect(), NULL, NULL);
280 // Find the best snap for this grid, including intersections of the grid-lines
281 bool old_val = _snapindicator;
282 _snapindicator = false;
283 Inkscape::SnappedPoint s = findBestSnap(Inkscape::SnapCandidatePoint(t_offset, Inkscape::SNAPSOURCE_GRID_PITCH), sc, false, false, true);
284 _snapindicator = old_val;
285 if (s.getSnapped() && (s.getSnapDistance() < nearest_distance)) {
286 // use getSnapDistance() instead of getWeightedDistance() here because the pointer's position
287 // doesn't tell us anything about which node to snap
288 success = true;
289 nearest_multiple = s.getPoint() - to_2geom(grid->origin);
290 nearest_distance = s.getSnapDistance();
291 bestSnappedPoint = s;
292 }
293 }
294 }
296 if (success) {
297 bestSnappedPoint.setPoint(origin + nearest_multiple);
298 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
299 return nearest_multiple;
300 }
301 }
303 return t;
304 }
306 /**
307 * \brief Try to snap a point along a constraint line to grids, guides or objects.
308 *
309 * Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
310 * i.e. snap in a specific direction on the two dimensional canvas to the nearest
311 * snap target.
312 *
313 * constrainedSnapReturnByRef() is equal in snapping behavior to
314 * constrainedSnap(), but the former returns the snapped point trough the referenced
315 * parameter p. This parameter p initially contains the position of the snap
316 * source and will we overwritten by the target position if snapping has occurred.
317 * This makes snapping transparent to the calling code. If this is not desired
318 * because either the calling code must know whether snapping has occurred, or
319 * because the original position should not be touched, then constrainedSnap() should
320 * be called instead.
321 *
322 * PS:
323 * 1) SnapManager::setup() must have been called before calling this method,
324 * but only once for a set of points
325 * 2) Only to be used when a single source point is to be snapped; it assumes
326 * that source_num = 0, which is inefficient when snapping sets our source points
328 *
329 * \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred
330 * \param source_type Detailed description of the source type, will be used by the snap indicator
331 * \param constraint The direction or line along which snapping must occur
332 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
333 */
335 void SnapManager::constrainedSnapReturnByRef(Geom::Point &p,
336 Inkscape::SnapSourceType const source_type,
337 Inkscape::Snapper::SnapConstraint const &constraint,
338 Geom::OptRect const &bbox_to_snap) const
339 {
340 Inkscape::SnappedPoint const s = constrainedSnap(Inkscape::SnapCandidatePoint(p, source_type, 0), constraint, bbox_to_snap);
341 s.getPoint(p);
342 }
344 /**
345 * \brief Try to snap a point along a constraint line to grids, guides or objects.
346 *
347 * Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
348 * i.e. snap in a specific direction on the two dimensional canvas to the nearest
349 * snap target. constrainedSnap is equal in snapping behavior to
350 * constrainedSnapReturnByRef(). Please read the comments of the latter for more details.
351 *
352 * PS: SnapManager::setup() must have been called before calling this method,
353 * but only once for a set of points
354 *
355 * \param p Source point to be snapped
356 * \param constraint The direction or line along which snapping must occur
357 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
358 */
360 Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::SnapCandidatePoint const &p,
361 Inkscape::Snapper::SnapConstraint const &constraint,
362 Geom::OptRect const &bbox_to_snap) const
363 {
364 // First project the mouse pointer onto the constraint
365 Geom::Point pp = constraint.projection(p.getPoint());
367 Inkscape::SnappedPoint no_snap = Inkscape::SnappedPoint(pp, p.getSourceType(), p.getSourceNum(), Inkscape::SNAPTARGET_CONSTRAINT, NR_HUGE, 0, false, true, false);
369 if (!someSnapperMightSnap()) {
370 // Always return point on constraint
371 return no_snap;
372 }
374 SnappedConstraints sc;
375 SnapperList const snappers = getSnappers();
376 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
377 (*i)->constrainedSnap(sc, p, bbox_to_snap, constraint, &_items_to_ignore);
378 }
380 Inkscape::SnappedPoint result = findBestSnap(p, sc, true);
382 if (result.getSnapped()) {
383 // only change the snap indicator if we really snapped to something
384 if (_snapindicator) {
385 _desktop->snapindicator->set_new_snaptarget(result);
386 }
387 return result;
388 }
389 return no_snap;
390 }
392 /**
393 * \brief Try to snap a point of a guide to another guide or to a node
394 *
395 * Try to snap a point of a guide to another guide or to a node in two degrees-
396 * of-freedom, i.e. snap in any direction on the two dimensional canvas to the
397 * nearest snap target. This method is used when dragging or rotating a guide
398 *
399 * PS: SnapManager::setup() must have been called before calling this method,
400 *
401 * \param p Current position of the point on the guide that is to be snapped; will be overwritten by the position of the snap target if snapping has occurred
402 * \param guide_normal Vector normal to the guide line
403 */
404 void SnapManager::guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const
405 {
406 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
407 return;
408 }
410 if (!(object.ThisSnapperMightSnap() || snapprefs.getSnapToGuides())) {
411 return;
412 }
414 Inkscape::SnapCandidatePoint candidate(p, Inkscape::SNAPSOURCE_GUIDE_ORIGIN);
415 if (drag_type == SP_DRAG_ROTATE) {
416 candidate = Inkscape::SnapCandidatePoint(p, Inkscape::SNAPSOURCE_GUIDE);
417 }
419 // Snap to nodes
420 SnappedConstraints sc;
421 if (object.ThisSnapperMightSnap()) {
422 object.guideFreeSnap(sc, p, guide_normal);
423 }
425 // Snap to guides & grid lines
426 SnapperList snappers = getGridSnappers();
427 snappers.push_back(&guide);
428 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
429 (*i)->freeSnap(sc, candidate, Geom::OptRect(), NULL, NULL);
430 }
432 Inkscape::SnappedPoint const s = findBestSnap(candidate, sc, false, false);
434 s.getPoint(p);
435 }
437 /**
438 * \brief Try to snap a point on a guide to the intersection with another guide or a path
439 *
440 * Try to snap a point on a guide to the intersection of that guide with another
441 * guide or with a path. The snapped point will lie somewhere on the guide-line,
442 * making this is a constrained snap, i.e. in only one degree-of-freedom.
443 * This method is used when dragging the origin of the guide along the guide itself.
444 *
445 * PS: SnapManager::setup() must have been called before calling this method,
446 *
447 * \param p Current position of the point on the guide that is to be snapped; will be overwritten by the position of the snap target if snapping has occurred
448 * \param guide_normal Vector normal to the guide line
449 */
451 void SnapManager::guideConstrainedSnap(Geom::Point &p, SPGuide const &guideline) const
452 {
453 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
454 return;
455 }
457 if (!(object.ThisSnapperMightSnap() || snapprefs.getSnapToGuides())) {
458 return;
459 }
461 Inkscape::SnapCandidatePoint candidate(p, Inkscape::SNAPSOURCE_GUIDE_ORIGIN, Inkscape::SNAPTARGET_UNDEFINED);
463 // Snap to nodes or paths
464 SnappedConstraints sc;
465 Inkscape::Snapper::SnapConstraint cl(guideline.point_on_line, Geom::rot90(guideline.normal_to_line));
466 if (object.ThisSnapperMightSnap()) {
467 object.constrainedSnap(sc, candidate, Geom::OptRect(), cl, NULL);
468 }
470 // Snap to guides & grid lines
471 SnapperList snappers = getGridSnappers();
472 snappers.push_back(&guide);
473 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
474 (*i)->constrainedSnap(sc, candidate, Geom::OptRect(), cl, NULL);
475 }
477 Inkscape::SnappedPoint const s = findBestSnap(candidate, sc, false);
478 s.getPoint(p);
479 }
481 /**
482 * \brief Method for snapping sets of points while they are being transformed
483 *
484 * Method for snapping sets of points while they are being transformed, when using
485 * for example the selector tool. This method is for internal use only, and should
486 * not have to be called directly. Use freeSnapTransalation(), constrainedSnapScale(),
487 * etc. instead.
488 *
489 * This is what is being done in this method: transform each point, find out whether
490 * a free snap or constrained snap is more appropriate, do the snapping, calculate
491 * some metrics to quantify the snap "distance", and see if it's better than the
492 * previous snap. Finally, the best ("nearest") snap from all these points is returned.
493 *
494 * \param points Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
495 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
496 * \param constrained true if the snap is constrained, e.g. for stretching or for purely horizontal translation.
497 * \param constraint The direction or line along which snapping must occur, if 'constrained' is true; otherwise undefined.
498 * \param transformation_type Type of transformation to apply to points before trying to snap them.
499 * \param transformation Description of the transformation; details depend on the type.
500 * \param origin Origin of the transformation, if applicable.
501 * \param dim Dimension to which the transformation applies, if applicable.
502 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
503 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
504 */
506 Inkscape::SnappedPoint SnapManager::_snapTransformed(
507 std::vector<Inkscape::SnapCandidatePoint> const &points,
508 Geom::Point const &pointer,
509 bool constrained,
510 Inkscape::Snapper::SnapConstraint const &constraint,
511 Transformation transformation_type,
512 Geom::Point const &transformation,
513 Geom::Point const &origin,
514 Geom::Dim2 dim,
515 bool uniform) const
516 {
517 /* We have a list of points, which we are proposing to transform in some way. We need to see
518 ** if any of these points, when transformed, snap to anything. If they do, we return the
519 ** appropriate transformation with `true'; otherwise we return the original scale with `false'.
520 */
522 /* Quick check to see if we have any snappers that are enabled
523 ** Also used to globally disable all snapping
524 */
525 if (someSnapperMightSnap() == false || points.size() == 0) {
526 return Inkscape::SnappedPoint(pointer);
527 }
529 std::vector<Inkscape::SnapCandidatePoint> transformed_points;
530 Geom::Rect bbox;
532 long source_num = 0;
533 for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = points.begin(); i != points.end(); i++) {
535 /* Work out the transformed version of this point */
536 Geom::Point transformed = _transformPoint(*i, transformation_type, transformation, origin, dim, uniform);
538 // add the current transformed point to the box hulling all transformed points
539 if (i == points.begin()) {
540 bbox = Geom::Rect(transformed, transformed);
541 } else {
542 bbox.expandTo(transformed);
543 }
545 transformed_points.push_back(Inkscape::SnapCandidatePoint(transformed, (*i).getSourceType(), source_num));
546 source_num++;
547 }
549 /* The current best transformation */
550 Geom::Point best_transformation = transformation;
552 /* The current best metric for the best transformation; lower is better, NR_HUGE
553 ** means that we haven't snapped anything.
554 */
555 Geom::Point best_scale_metric(NR_HUGE, NR_HUGE);
556 Inkscape::SnappedPoint best_snapped_point;
557 g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point
558 g_assert(best_snapped_point.getAtIntersection() == false);
560 // Warnings for the devs
561 if (constrained && transformation_type == SCALE && !uniform) {
562 g_warning("Non-uniform constrained scaling is not supported!");
563 }
565 if (!constrained && transformation_type == ROTATE) {
566 // We do not yet allow for simultaneous rotation and scaling
567 g_warning("Unconstrained rotation is not supported!");
568 }
570 std::vector<Inkscape::SnapCandidatePoint>::iterator j = transformed_points.begin();
572 // std::cout << std::endl;
573 bool first_free_snap = true;
574 for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = points.begin(); i != points.end(); i++) {
576 /* Snap it */
577 Inkscape::SnappedPoint snapped_point;
578 Inkscape::Snapper::SnapConstraint dedicated_constraint = constraint;
579 Geom::Point const b = ((*i).getPoint() - origin); // vector to original point (not the transformed point! required for rotations!)
581 if (constrained) {
582 if (((transformation_type == SCALE || transformation_type == STRETCH) && uniform)) {
583 // When uniformly scaling, each point will have its own unique constraint line,
584 // running from the scaling origin to the original untransformed point. We will
585 // calculate that line here
586 dedicated_constraint = Inkscape::Snapper::SnapConstraint(origin, b);
587 } else if (transformation_type == ROTATE) {
588 Geom::Coord r = Geom::L2(b); // the radius of the circular constraint
589 if (r < 1e-9) { // points too close to the rotation center will not move. Don't try to snap these
590 // as they will always yield a perfect snap result if they're already snapped beforehand (e.g.
591 // when the transformation center has been snapped to a grid intersection in the selector tool)
592 continue; // skip this SnapCandidate and continue with the next one
593 // PS1: Apparently we don't have to do this for skewing, but why?
594 // PS2: We cannot easily filter these points upstream, e.g. in the grab() method (seltrans.cpp)
595 // because the rotation center will change when pressing shift, and grab() won't be recalled.
596 // Filtering could be done in handleRequest() (again in seltrans.cpp), by iterating through
597 // the snap candidates. But hey, we're iterating here anyway.
598 }
599 dedicated_constraint = Inkscape::Snapper::SnapConstraint(origin, b, r);
600 } else if (transformation_type == STRETCH) { // when non-uniform stretching {
601 dedicated_constraint = Inkscape::Snapper::SnapConstraint((*i).getPoint(), component_vectors[dim]);
602 } else if (transformation_type == TRANSLATE) {
603 // When doing a constrained translation, all points will move in the same direction, i.e.
604 // either horizontally or vertically. The lines along which they move are therefore all
605 // parallel, but might not be colinear. Therefore we will have to specify the point through
606 // which the constraint-line runs here, for each point individually. (we could also have done this
607 // earlier on, e.g. in seltrans.cpp but we're being lazy there and don't want to add an iteration loop)
608 dedicated_constraint = Inkscape::Snapper::SnapConstraint((*i).getPoint(), constraint.getDirection());
609 } // else: leave the original constraint, e.g. for skewing
610 snapped_point = constrainedSnap(*j, dedicated_constraint, bbox);
611 } else {
612 bool const c1 = fabs(b[Geom::X]) < 1e-6;
613 bool const c2 = fabs(b[Geom::Y]) < 1e-6;
614 if (transformation_type == SCALE && (c1 || c2) && !(c1 && c2)) {
615 // When scaling, a point aligned either horizontally or vertically with the origin can only
616 // move in that specific direction; therefore it should only snap in that direction, otherwise
617 // we will get snapped points with an invalid transformation
618 dedicated_constraint = Inkscape::Snapper::SnapConstraint(origin, component_vectors[c1]);
619 snapped_point = constrainedSnap(*j, dedicated_constraint, bbox);
620 } else {
621 // If we have a collection of SnapCandidatePoints, with mixed constrained snapping and free snapping
622 // requirements, then freeSnap might never see the SnapCandidatePoint with source_num == 0. The freeSnap()
623 // method in the object snapper depends on this, because only for source-num == 0 the target nodes will
624 // be collected. Therefore we enforce that the first SnapCandidatePoint that is to be freeSnapped always
625 // has source_num == 0;
626 // TODO: This is a bit ugly so fix this; do we need sourcenum for anything else? if we don't then get rid
627 // of it and explicitely communicate to the object snapper that this is a first point
628 if (first_free_snap) {
629 (*j).setSourceNum(0);
630 first_free_snap = false;
631 }
632 snapped_point = freeSnap(*j, bbox);
633 }
634 }
635 // std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl;
636 snapped_point.setPointerDistance(Geom::L2(pointer - (*i).getPoint()));
638 Geom::Point result;
640 if (snapped_point.getSnapped()) {
641 /* We snapped. Find the transformation that describes where the snapped point has
642 ** ended up, and also the metric for this transformation.
643 */
644 Geom::Point const a = snapped_point.getPoint() - origin; // vector to snapped point
645 //Geom::Point const b = (*i - origin); // vector to original point
647 switch (transformation_type) {
648 case TRANSLATE:
649 result = snapped_point.getPoint() - (*i).getPoint();
650 /* Consider the case in which a box is almost aligned with a grid in both
651 * horizontal and vertical directions. The distance to the intersection of
652 * the grid lines will always be larger then the distance to a single grid
653 * line. If we prefer snapping to an intersection instead of to a single
654 * grid line, then we cannot use "metric = Geom::L2(result)". Therefore the
655 * snapped distance will be used as a metric. Please note that the snapped
656 * distance is defined as the distance to the nearest line of the intersection,
657 * and not to the intersection itself!
658 */
659 // Only for translations, the relevant metric will be the real snapped distance,
660 // so we don't have to do anything special here
661 break;
662 case SCALE:
663 {
664 result = Geom::Point(NR_HUGE, NR_HUGE);
665 // If this point *i is horizontally or vertically aligned with
666 // the origin of the scaling, then it will scale purely in X or Y
667 // We can therefore only calculate the scaling in this direction
668 // and the scaling factor for the other direction should remain
669 // untouched (unless scaling is uniform of course)
670 for (int index = 0; index < 2; index++) {
671 if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
672 if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
673 result[index] = a[index] / b[index]; // then calculate it!
674 }
675 // we might leave result[1-index] = NR_HUGE
676 // if scaling didn't occur in the other direction
677 }
678 }
679 if (uniform) {
680 if (fabs(result[0]) < fabs(result[1])) {
681 result[1] = result[0];
682 } else {
683 result[0] = result[1];
684 }
685 }
686 // Compare the resulting scaling with the desired scaling
687 Geom::Point scale_metric = Geom::abs(result - transformation); // One or both of its components might be NR_HUGE
688 snapped_point.setSnapDistance(std::min(scale_metric[0], scale_metric[1]));
689 snapped_point.setSecondSnapDistance(std::max(scale_metric[0], scale_metric[1]));
690 break;
691 }
692 case STRETCH:
693 result = Geom::Point(NR_HUGE, NR_HUGE);
694 if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
695 result[dim] = a[dim] / b[dim];
696 result[1-dim] = uniform ? result[dim] : 1;
697 } else { // STRETCHING might occur for this point, but only when the stretching is uniform
698 if (uniform && fabs(b[1-dim]) > 1e-6) {
699 result[1-dim] = a[1-dim] / b[1-dim];
700 result[dim] = result[1-dim];
701 }
702 }
703 // Store the metric for this transformation as a virtual distance
704 snapped_point.setSnapDistance(std::abs(result[dim] - transformation[dim]));
705 snapped_point.setSecondSnapDistance(NR_HUGE);
706 break;
707 case SKEW:
708 result[0] = (snapped_point.getPoint()[dim] - ((*i).getPoint())[dim]) / b[1 - dim]; // skew factor
709 result[1] = transformation[1]; // scale factor
710 // Store the metric for this transformation as a virtual distance
711 snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
712 snapped_point.setSecondSnapDistance(NR_HUGE);
713 break;
714 case ROTATE:
715 // a is vector to snapped point; b is vector to original point; now lets calculate angle between a and b
716 result[0] = atan2(Geom::dot(Geom::rot90(b), a), Geom::dot(b, a));
717 result[1] = result[1]; // how else should we store an angle in a point ;-)
718 // Store the metric for this transformation as a virtual distance (we're storing an angle)
719 snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
720 snapped_point.setSecondSnapDistance(NR_HUGE);
721 break;
722 default:
723 g_assert_not_reached();
724 }
726 if (best_snapped_point.isOtherSnapBetter(snapped_point, true)) {
727 best_transformation = result;
728 best_snapped_point = snapped_point;
729 }
730 }
732 j++;
733 }
735 Geom::Coord best_metric;
736 if (transformation_type == SCALE) {
737 // When scaling, don't ever exit with one of scaling components set to NR_HUGE
738 for (int index = 0; index < 2; index++) {
739 if (best_transformation[index] == NR_HUGE) {
740 if (uniform && best_transformation[1-index] < NR_HUGE) {
741 best_transformation[index] = best_transformation[1-index];
742 } else {
743 best_transformation[index] = transformation[index];
744 }
745 }
746 }
747 }
749 best_metric = best_snapped_point.getSnapDistance();
750 best_snapped_point.setTransformation(best_transformation);
751 // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
752 // These rounding errors might be caused by NRRects, see bug #1584301
753 best_snapped_point.setSnapDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
754 return best_snapped_point;
755 }
758 /**
759 * \brief Apply a translation to a set of points and try to snap freely in 2 degrees-of-freedom
760 *
761 * \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
762 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
763 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred
764 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
765 */
767 Inkscape::SnappedPoint SnapManager::freeSnapTranslate(std::vector<Inkscape::SnapCandidatePoint> const &p,
768 Geom::Point const &pointer,
769 Geom::Point const &tr) const
770 {
771 if (p.size() == 1) {
772 Geom::Point pt = _transformPoint(p.at(0), TRANSLATE, tr, Geom::Point(0,0), Geom::X, false);
773 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
774 }
778 return _snapTransformed(p, pointer, false, Geom::Point(0,0), TRANSLATE, tr, Geom::Point(0,0), Geom::X, false);
779 }
781 /**
782 * \brief Apply a translation to a set of points and try to snap along a constraint
783 *
784 * \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
785 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
786 * \param constraint The direction or line along which snapping must occur.
787 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred.
788 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
789 */
791 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslate(std::vector<Inkscape::SnapCandidatePoint> const &p,
792 Geom::Point const &pointer,
793 Inkscape::Snapper::SnapConstraint const &constraint,
794 Geom::Point const &tr) const
795 {
796 if (p.size() == 1) {
797 Geom::Point pt = _transformPoint(p.at(0), TRANSLATE, tr, Geom::Point(0,0), Geom::X, false);
798 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
799 }
801 return _snapTransformed(p, pointer, true, constraint, TRANSLATE, tr, Geom::Point(0,0), Geom::X, false);
802 }
805 /**
806 * \brief Apply a scaling to a set of points and try to snap freely in 2 degrees-of-freedom
807 *
808 * \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
809 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
810 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
811 * \param o Origin of the scaling
812 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
813 */
815 Inkscape::SnappedPoint SnapManager::freeSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
816 Geom::Point const &pointer,
817 Geom::Scale const &s,
818 Geom::Point const &o) const
819 {
820 if (p.size() == 1) {
821 Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
822 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
823 }
825 return _snapTransformed(p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
826 }
829 /**
830 * \brief Apply a scaling to a set of points and snap such that the aspect ratio of the selection is preserved
831 *
832 * \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
833 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
834 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
835 * \param o Origin of the scaling
836 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
837 */
839 Inkscape::SnappedPoint SnapManager::constrainedSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
840 Geom::Point const &pointer,
841 Geom::Scale const &s,
842 Geom::Point const &o) const
843 {
844 // When constrained scaling, only uniform scaling is supported.
845 if (p.size() == 1) {
846 Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
847 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
848 }
850 return _snapTransformed(p, pointer, true, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
851 }
853 /**
854 * \brief Apply a stretch to a set of points and snap such that the direction of the stretch is preserved
855 *
856 * \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
857 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
858 * \param s Proposed stretch; the final stretch can only be calculated after snapping has occurred
859 * \param o Origin of the stretching
860 * \param d Dimension in which to apply proposed stretch.
861 * \param u true if the stretch should be uniform (i.e. to be applied equally in both dimensions)
862 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
863 */
865 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(std::vector<Inkscape::SnapCandidatePoint> const &p,
866 Geom::Point const &pointer,
867 Geom::Coord const &s,
868 Geom::Point const &o,
869 Geom::Dim2 d,
870 bool u) const
871 {
872 if (p.size() == 1) {
873 Geom::Point pt = _transformPoint(p.at(0), STRETCH, Geom::Point(s, s), o, d, u);
874 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
875 }
877 return _snapTransformed(p, pointer, true, Geom::Point(0,0), STRETCH, Geom::Point(s, s), o, d, u);
878 }
880 /**
881 * \brief Apply a skew to a set of points and snap such that the direction of the skew is preserved
882 *
883 * \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
884 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
885 * \param constraint The direction or line along which snapping must occur.
886 * \param s Proposed skew; the final skew can only be calculated after snapping has occurred
887 * \param o Origin of the proposed skew
888 * \param d Dimension in which to apply proposed skew.
889 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
890 */
892 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(std::vector<Inkscape::SnapCandidatePoint> const &p,
893 Geom::Point const &pointer,
894 Inkscape::Snapper::SnapConstraint const &constraint,
895 Geom::Point const &s,
896 Geom::Point const &o,
897 Geom::Dim2 d) const
898 {
899 // "s" contains skew factor in s[0], and scale factor in s[1]
901 // Snapping the nodes of the bounding box of a selection that is being transformed, will only work if
902 // the transformation of the bounding box is equal to the transformation of the individual nodes. This is
903 // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
904 // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
905 // of bounding boxes is not allowed here.
906 if (p.size() > 0) {
907 g_assert(!(p.at(0).getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY));
908 }
910 if (p.size() == 1) {
911 Geom::Point pt = _transformPoint(p.at(0), SKEW, s, o, d, false);
912 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
913 }
915 return _snapTransformed(p, pointer, true, constraint, SKEW, s, o, d, false);
916 }
918 /**
919 * \brief Apply a rotation to a set of points and snap, without scaling
920 *
921 * \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
922 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
923 * \param angle Proposed rotation (in radians); the final rotation can only be calculated after snapping has occurred
924 * \param o Origin of the rotation
925 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
926 */
928 Inkscape::SnappedPoint SnapManager::constrainedSnapRotate(std::vector<Inkscape::SnapCandidatePoint> const &p,
929 Geom::Point const &pointer,
930 Geom::Coord const &angle,
931 Geom::Point const &o) const
932 {
933 // Snapping the nodes of the bounding box of a selection that is being transformed, will only work if
934 // the transformation of the bounding box is equal to the transformation of the individual nodes. This is
935 // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
936 // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
937 // of bounding boxes is not allowed here.
939 if (p.size() == 1) {
940 Geom::Point pt = _transformPoint(p.at(0), ROTATE, Geom::Point(angle, angle), o, Geom::X, false);
941 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
942 }
944 return _snapTransformed(p, pointer, true, Geom::Point(0,0), ROTATE, Geom::Point(angle, angle), o, Geom::X, false);
946 }
948 /**
949 * \brief Given a set of possible snap targets, find the best target (which is not necessarily
950 * also the nearest target), and show the snap indicator if requested
951 *
952 * \param p Source point to be snapped
953 * \param sc A structure holding all snap targets that have been found so far
954 * \param constrained True if the snap is constrained, e.g. for stretching or for purely horizontal translation.
955 * \param noCurves If true, then do consider snapping to intersections of curves, but not to the curves themselves
956 * \param allowOffScreen If true, then snapping to points which are off the screen is allowed (needed for example when pasting to the grid)
957 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
958 */
960 Inkscape::SnappedPoint SnapManager::findBestSnap(Inkscape::SnapCandidatePoint const &p,
961 SnappedConstraints const &sc,
962 bool constrained,
963 bool noCurves,
964 bool allowOffScreen) const
965 {
968 /*
969 std::cout << "Type and number of snapped constraints: " << std::endl;
970 std::cout << " Points : " << sc.points.size() << std::endl;
971 std::cout << " Lines : " << sc.lines.size() << std::endl;
972 std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
973 std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
974 std::cout << " Curves : " << sc.curves.size()<< std::endl;
975 */
977 // Store all snappoints
978 std::list<Inkscape::SnappedPoint> sp_list;
980 // search for the closest snapped point
981 Inkscape::SnappedPoint closestPoint;
982 if (getClosestSP(sc.points, closestPoint)) {
983 sp_list.push_back(closestPoint);
984 }
986 // search for the closest snapped curve
987 if (!noCurves) {
988 Inkscape::SnappedCurve closestCurve;
989 if (getClosestCurve(sc.curves, closestCurve)) {
990 sp_list.push_back(Inkscape::SnappedPoint(closestCurve));
991 }
992 }
994 if (snapprefs.getSnapIntersectionCS()) {
995 // search for the closest snapped intersection of curves
996 Inkscape::SnappedPoint closestCurvesIntersection;
997 if (getClosestIntersectionCS(sc.curves, p.getPoint(), closestCurvesIntersection, _desktop->dt2doc())) {
998 closestCurvesIntersection.setSource(p.getSourceType());
999 sp_list.push_back(closestCurvesIntersection);
1000 }
1001 }
1003 // search for the closest snapped grid line
1004 Inkscape::SnappedLine closestGridLine;
1005 if (getClosestSL(sc.grid_lines, closestGridLine)) {
1006 sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
1007 }
1009 // search for the closest snapped guide line
1010 Inkscape::SnappedLine closestGuideLine;
1011 if (getClosestSL(sc.guide_lines, closestGuideLine)) {
1012 sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
1013 }
1015 // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
1016 // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
1018 // When doing a constrained snap however, we're already at an intersection of the constrained line and
1019 // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
1020 // no need to look for additional intersections
1021 if (!constrained) {
1022 // search for the closest snapped intersection of grid lines
1023 Inkscape::SnappedPoint closestGridPoint;
1024 if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
1025 closestGridPoint.setSource(p.getSourceType());
1026 closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
1027 sp_list.push_back(closestGridPoint);
1028 }
1030 // search for the closest snapped intersection of guide lines
1031 Inkscape::SnappedPoint closestGuidePoint;
1032 if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
1033 closestGuidePoint.setSource(p.getSourceType());
1034 closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
1035 sp_list.push_back(closestGuidePoint);
1036 }
1038 // search for the closest snapped intersection of grid with guide lines
1039 if (snapprefs.getSnapIntersectionGG()) {
1040 Inkscape::SnappedPoint closestGridGuidePoint;
1041 if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
1042 closestGridGuidePoint.setSource(p.getSourceType());
1043 closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
1044 sp_list.push_back(closestGridGuidePoint);
1045 }
1046 }
1047 }
1049 // now let's see which snapped point gets a thumbs up
1050 Inkscape::SnappedPoint bestSnappedPoint(p.getPoint());
1051 // std::cout << "Finding the best snap..." << std::endl;
1052 for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
1053 // std::cout << "sp = " << (*i).getPoint() << " | source = " << (*i).getSource() << " | target = " << (*i).getTarget();
1054 bool onScreen = _desktop->get_display_area().contains((*i).getPoint());
1055 if (onScreen || allowOffScreen) { // Only snap to points which are not off the screen
1056 if ((*i).getSnapDistance() <= (*i).getTolerance()) { // Only snap to points within snapping range
1057 // if it's the first point, or if it is closer than the best snapped point so far
1058 if (i == sp_list.begin() || bestSnappedPoint.isOtherSnapBetter(*i, false)) {
1059 // then prefer this point over the previous one
1060 bestSnappedPoint = *i;
1061 }
1062 }
1063 }
1064 // std::cout << std::endl;
1065 }
1067 // Update the snap indicator, if requested
1068 if (_snapindicator) {
1069 if (bestSnappedPoint.getSnapped()) {
1070 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
1071 } else {
1072 _desktop->snapindicator->remove_snaptarget();
1073 }
1074 }
1076 // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl;
1077 return bestSnappedPoint;
1078 }
1080 /// Convenience shortcut when there is only one item to ignore
1081 void SnapManager::setup(SPDesktop const *desktop,
1082 bool snapindicator,
1083 SPItem const *item_to_ignore,
1084 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1085 SPGuide *guide_to_ignore)
1086 {
1087 g_assert(desktop != NULL);
1088 _items_to_ignore.clear();
1089 _items_to_ignore.push_back(item_to_ignore);
1090 _desktop = desktop;
1091 _snapindicator = snapindicator;
1092 _unselected_nodes = unselected_nodes;
1093 _guide_to_ignore = guide_to_ignore;
1094 _rotation_center_source_item = NULL;
1095 }
1097 /**
1098 * \brief Prepare the snap manager for the actual snapping, which includes building a list of snap targets
1099 * to ignore and toggling the snap indicator
1100 *
1101 * There are two overloaded setup() methods, of which the other one only allows for a single item to be ignored
1102 * whereas this one will take a list of items to ignore
1103 *
1104 * \param desktop Reference to the desktop to which this snap manager is attached
1105 * \param snapindicator If true then a snap indicator will be displayed automatically (when enabled in the preferences)
1106 * \param items_to_ignore These items will not be snapped to, e.g. the items that are currently being dragged. This avoids "self-snapping"
1107 * \param unselected_nodes Stationary nodes of the path that is currently being edited in the node tool and
1108 * that can be snapped too. Nodes not in this list will not be snapped to, to avoid "self-snapping". Of each
1109 * unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored
1110 * \param guide_to_ignore Guide that is currently being dragged and should not be snapped to
1111 */
1113 void SnapManager::setup(SPDesktop const *desktop,
1114 bool snapindicator,
1115 std::vector<SPItem const *> &items_to_ignore,
1116 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1117 SPGuide *guide_to_ignore)
1118 {
1119 g_assert(desktop != NULL);
1120 _items_to_ignore = items_to_ignore;
1121 _desktop = desktop;
1122 _snapindicator = snapindicator;
1123 _unselected_nodes = unselected_nodes;
1124 _guide_to_ignore = guide_to_ignore;
1125 _rotation_center_source_item = NULL;
1126 }
1128 /// Setup, taking the list of items to ignore from the desktop's selection.
1129 void SnapManager::setupIgnoreSelection(SPDesktop const *desktop,
1130 bool snapindicator,
1131 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1132 SPGuide *guide_to_ignore)
1133 {
1134 _desktop = desktop;
1135 _snapindicator = snapindicator;
1136 _unselected_nodes = unselected_nodes;
1137 _guide_to_ignore = guide_to_ignore;
1138 _rotation_center_source_item = NULL;
1139 _items_to_ignore.clear();
1141 Inkscape::Selection *sel = _desktop->selection;
1142 GSList const *items = sel->itemList();
1143 for (GSList *i = const_cast<GSList*>(items); i; i = i->next) {
1144 _items_to_ignore.push_back(static_cast<SPItem const *>(i->data));
1145 }
1146 }
1148 SPDocument *SnapManager::getDocument() const
1149 {
1150 return _named_view->document;
1151 }
1153 /**
1154 * \brief Takes an untransformed point, applies the given transformation, and returns the transformed point. Eliminates lots of duplicated code
1155 *
1156 * \param p The untransformed position of the point, paired with an identifier of the type of the snap source.
1157 * \param transformation_type Type of transformation to apply.
1158 * \param transformation Mathematical description of the transformation; details depend on the type.
1159 * \param origin Origin of the transformation, if applicable.
1160 * \param dim Dimension to which the transformation applies, if applicable.
1161 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
1162 * \return The position of the point after transformation
1163 */
1165 Geom::Point SnapManager::_transformPoint(Inkscape::SnapCandidatePoint const &p,
1166 Transformation const transformation_type,
1167 Geom::Point const &transformation,
1168 Geom::Point const &origin,
1169 Geom::Dim2 const dim,
1170 bool const uniform) const
1171 {
1172 /* Work out the transformed version of this point */
1173 Geom::Point transformed;
1174 switch (transformation_type) {
1175 case TRANSLATE:
1176 transformed = p.getPoint() + transformation;
1177 break;
1178 case SCALE:
1179 transformed = (p.getPoint() - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
1180 break;
1181 case STRETCH:
1182 {
1183 Geom::Scale s(1, 1);
1184 if (uniform)
1185 s[Geom::X] = s[Geom::Y] = transformation[dim];
1186 else {
1187 s[dim] = transformation[dim];
1188 s[1 - dim] = 1;
1189 }
1190 transformed = ((p.getPoint() - origin) * s) + origin;
1191 break;
1192 }
1193 case SKEW:
1194 // Apply the skew factor
1195 transformed[dim] = (p.getPoint())[dim] + transformation[0] * ((p.getPoint())[1 - dim] - origin[1 - dim]);
1196 // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
1197 // Apply that scale factor here
1198 transformed[1-dim] = (p.getPoint() - origin)[1 - dim] * transformation[1] + origin[1 - dim];
1199 break;
1200 case ROTATE:
1201 // for rotations: transformation[0] stores the angle in radians
1202 transformed = (p.getPoint() - origin) * Geom::Rotate(transformation[0]) + origin;
1203 break;
1204 default:
1205 g_assert_not_reached();
1206 }
1208 return transformed;
1209 }
1211 /**
1212 * \brief Mark the location of the snap source (not the snap target!) on the canvas by drawing a symbol
1213 *
1214 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
1215 * \param p The transformed position of the source point, paired with an identifier of the type of the snap source.
1216 */
1218 void SnapManager::_displaySnapsource(Inkscape::SnapCandidatePoint const &p) const {
1220 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
1221 if (prefs->getBool("/options/snapclosestonly/value")) {
1222 bool p_is_a_node = p.getSourceType() & Inkscape::SNAPSOURCE_NODE_CATEGORY;
1223 bool p_is_a_bbox = p.getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY;
1224 bool p_is_other = p.getSourceType() & Inkscape::SNAPSOURCE_OTHER_CATEGORY;
1226 if (snapprefs.getSnapEnabledGlobally() && (p_is_other || (p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) {
1227 _desktop->snapindicator->set_new_snapsource(p);
1228 } else {
1229 _desktop->snapindicator->remove_snapsource();
1230 }
1231 }
1232 }
1234 /*
1235 Local Variables:
1236 mode:c++
1237 c-file-style:"stroustrup"
1238 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1239 indent-tabs-mode:nil
1240 fill-column:99
1241 End:
1242 */
1243 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :