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 //TODO: SnapCandidatePoint and point_type are somewhat redundant; can't we get rid of the point_type parameter?
178 Inkscape::SnappedPoint const s = freeSnap(Inkscape::SnapCandidatePoint(p, source_type), bbox_to_snap);
179 s.getPoint(p);
180 }
183 /**
184 * \brief Try to snap a point to grids, guides or objects.
185 *
186 * Try to snap a point to grids, guides or objects, in two degrees-of-freedom,
187 * i.e. snap in any direction on the two dimensional canvas to the nearest
188 * snap target. freeSnap() is equal in snapping behavior to
189 * freeSnapReturnByRef(). Please read the comments of the latter for more details
190 *
191 * PS: SnapManager::setup() must have been called before calling this method,
192 * but only once for a set of points
193 *
194 * \param p Source point to be snapped
195 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
196 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
197 */
200 Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::SnapCandidatePoint const &p,
201 Geom::OptRect const &bbox_to_snap) const
202 {
203 if (!someSnapperMightSnap()) {
204 return Inkscape::SnappedPoint(p, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false, false);
205 }
207 SnappedConstraints sc;
208 SnapperList const snappers = getSnappers();
210 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
211 (*i)->freeSnap(sc, p, bbox_to_snap, &_items_to_ignore, _unselected_nodes);
212 }
214 return findBestSnap(p, sc, false);
215 }
217 void SnapManager::preSnap(Inkscape::SnapCandidatePoint const &p)
218 {
219 // setup() must have been called before calling this method!
221 if (_snapindicator) {
222 _snapindicator = false; // prevent other methods from drawing a snap indicator; we want to control this here
223 Inkscape::SnappedPoint s = freeSnap(p);
224 if (s.getSnapped()) {
225 _desktop->snapindicator->set_new_snaptarget(s, true);
226 } else {
227 _desktop->snapindicator->remove_snaptarget(true);
228 }
229 _snapindicator = true; // restore the original value
230 }
231 }
233 /**
234 * \brief Snap to the closest multiple of a grid pitch
235 *
236 * When pasting, we would like to snap to the grid. Problem is that we don't know which
237 * nodes were aligned to the grid at the time of copying, so we don't know which nodes
238 * to snap. If we'd snap an unaligned node to the grid, previously aligned nodes would
239 * become unaligned. That's undesirable. Instead we will make sure that the offset
240 * between the source and its pasted copy is a multiple of the grid pitch. If the source
241 * was aligned, then the copy will therefore also be aligned.
242 *
243 * PS: Whether we really find a multiple also depends on the snapping range! Most users
244 * will have "always snap" enabled though, in which case a multiple will always be found.
245 * PS2: When multiple grids are present then the result will become ambiguous. There is no
246 * way to control to which grid this method will snap.
247 *
248 * \param t Vector that represents the offset of the pasted copy with respect to the original
249 * \return Offset vector after snapping to the closest multiple of a grid pitch
250 */
252 Geom::Point SnapManager::multipleOfGridPitch(Geom::Point const &t, Geom::Point const &origin)
253 {
254 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally())
255 return t;
257 if (_desktop && _desktop->gridsEnabled()) {
258 bool success = false;
259 Geom::Point nearest_multiple;
260 Geom::Coord nearest_distance = NR_HUGE;
261 Inkscape::SnappedPoint bestSnappedPoint(t);
263 // It will snap to the grid for which we find the closest snap. This might be a different
264 // grid than to which the objects were initially aligned. I don't see an easy way to fix
265 // this, so when using multiple grids one can get unexpected results
267 // Cannot use getGridSnappers() because we need both the grids AND their snappers
268 // Therefore we iterate through all grids manually
269 for (GSList const *l = _named_view->grids; l != NULL; l = l->next) {
270 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
271 const Inkscape::Snapper* snapper = grid->snapper;
272 if (snapper && snapper->ThisSnapperMightSnap()) {
273 // To find the nearest multiple of the grid pitch for a given translation t, we
274 // will use the grid snapper. Simply snapping the value t to the grid will do, but
275 // only if the origin of the grid is at (0,0). If it's not then compensate for this
276 // in the translation t
277 Geom::Point const t_offset = t + grid->origin;
278 SnappedConstraints sc;
279 // Only the first three parameters are being used for grid snappers
280 snapper->freeSnap(sc, Inkscape::SnapCandidatePoint(t_offset, Inkscape::SNAPSOURCE_GRID_PITCH),Geom::OptRect(), NULL, NULL);
281 // Find the best snap for this grid, including intersections of the grid-lines
282 bool old_val = _snapindicator;
283 _snapindicator = false;
284 Inkscape::SnappedPoint s = findBestSnap(Inkscape::SnapCandidatePoint(t_offset, Inkscape::SNAPSOURCE_GRID_PITCH), sc, false, false, true);
285 _snapindicator = old_val;
286 if (s.getSnapped() && (s.getSnapDistance() < nearest_distance)) {
287 // use getSnapDistance() instead of getWeightedDistance() here because the pointer's position
288 // doesn't tell us anything about which node to snap
289 success = true;
290 nearest_multiple = s.getPoint() - to_2geom(grid->origin);
291 nearest_distance = s.getSnapDistance();
292 bestSnappedPoint = s;
293 }
294 }
295 }
297 if (success) {
298 bestSnappedPoint.setPoint(origin + nearest_multiple);
299 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
300 return nearest_multiple;
301 }
302 }
304 return t;
305 }
307 /**
308 * \brief Try to snap a point along a constraint line to grids, guides or objects.
309 *
310 * Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
311 * i.e. snap in a specific direction on the two dimensional canvas to the nearest
312 * snap target.
313 *
314 * constrainedSnapReturnByRef() is equal in snapping behavior to
315 * constrainedSnap(), but the former returns the snapped point trough the referenced
316 * parameter p. This parameter p initially contains the position of the snap
317 * source and will we overwritten by the target position if snapping has occurred.
318 * This makes snapping transparent to the calling code. If this is not desired
319 * because either the calling code must know whether snapping has occurred, or
320 * because the original position should not be touched, then constrainedSnap() should
321 * be called instead.
322 *
323 * PS:
324 * 1) SnapManager::setup() must have been called before calling this method,
325 * but only once for a set of points
326 * 2) Only to be used when a single source point is to be snapped; it assumes
327 * that source_num = 0, which is inefficient when snapping sets our source points
329 *
330 * \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred
331 * \param source_type Detailed description of the source type, will be used by the snap indicator
332 * \param constraint The direction or line along which snapping must occur
333 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
334 */
336 void SnapManager::constrainedSnapReturnByRef(Geom::Point &p,
337 Inkscape::SnapSourceType const source_type,
338 Inkscape::Snapper::SnapConstraint const &constraint,
339 Geom::OptRect const &bbox_to_snap) const
340 {
341 Inkscape::SnappedPoint const s = constrainedSnap(Inkscape::SnapCandidatePoint(p, source_type, 0), constraint, bbox_to_snap);
342 s.getPoint(p);
343 }
345 /**
346 * \brief Try to snap a point along a constraint line to grids, guides or objects.
347 *
348 * Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
349 * i.e. snap in a specific direction on the two dimensional canvas to the nearest
350 * snap target. constrainedSnap is equal in snapping behavior to
351 * constrainedSnapReturnByRef(). Please read the comments of the latter for more details.
352 *
353 * PS: SnapManager::setup() must have been called before calling this method,
354 * but only once for a set of points
355 *
356 * \param p Source point to be snapped
357 * \param constraint The direction or line along which snapping must occur
358 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
359 */
361 Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::SnapCandidatePoint const &p,
362 Inkscape::Snapper::SnapConstraint const &constraint,
363 Geom::OptRect const &bbox_to_snap) const
364 {
365 // First project the mouse pointer onto the constraint
366 Geom::Point pp = constraint.projection(p.getPoint());
368 Inkscape::SnappedPoint no_snap = Inkscape::SnappedPoint(pp, p.getSourceType(), p.getSourceNum(), Inkscape::SNAPTARGET_CONSTRAINT, NR_HUGE, 0, false, true, false);
370 if (!someSnapperMightSnap()) {
371 // Always return point on constraint
372 return no_snap;
373 }
375 SnappedConstraints sc;
376 SnapperList const snappers = getSnappers();
377 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
378 (*i)->constrainedSnap(sc, p, bbox_to_snap, constraint, &_items_to_ignore);
379 }
381 Inkscape::SnappedPoint result = findBestSnap(p, sc, true);
383 if (result.getSnapped()) {
384 // only change the snap indicator if we really snapped to something
385 if (_snapindicator) {
386 _desktop->snapindicator->set_new_snaptarget(result);
387 }
388 return result;
389 }
390 return no_snap;
391 }
393 /**
394 * \brief Try to snap a point of a guide to another guide or to a node
395 *
396 * Try to snap a point of a guide to another guide or to a node in two degrees-
397 * of-freedom, i.e. snap in any direction on the two dimensional canvas to the
398 * nearest snap target. This method is used when dragging or rotating a guide
399 *
400 * PS: SnapManager::setup() must have been called before calling this method,
401 *
402 * \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
403 * \param guide_normal Vector normal to the guide line
404 */
405 void SnapManager::guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const
406 {
407 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
408 return;
409 }
411 if (!(object.GuidesMightSnap() || snapprefs.getSnapToGuides())) {
412 return;
413 }
415 Inkscape::SnapCandidatePoint candidate(p, Inkscape::SNAPSOURCE_GUIDE_ORIGIN);
416 if (drag_type == SP_DRAG_ROTATE) {
417 candidate = Inkscape::SnapCandidatePoint(p, Inkscape::SNAPSOURCE_GUIDE);
418 }
420 // Snap to nodes
421 SnappedConstraints sc;
422 if (object.GuidesMightSnap()) {
423 object.guideFreeSnap(sc, p, guide_normal);
424 }
426 // Snap to guides & grid lines
427 SnapperList snappers = getGridSnappers();
428 snappers.push_back(&guide);
429 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
430 (*i)->freeSnap(sc, candidate, Geom::OptRect(), NULL, NULL);
431 }
433 Inkscape::SnappedPoint const s = findBestSnap(candidate, sc, false, false);
435 s.getPoint(p);
436 }
438 /**
439 * \brief Try to snap a point on a guide to the intersection with another guide or a path
440 *
441 * Try to snap a point on a guide to the intersection of that guide with another
442 * guide or with a path. The snapped point will lie somewhere on the guide-line,
443 * making this is a constrained snap, i.e. in only one degree-of-freedom.
444 * This method is used when dragging the origin of the guide along the guide itself.
445 *
446 * PS: SnapManager::setup() must have been called before calling this method,
447 *
448 * \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
449 * \param guide_normal Vector normal to the guide line
450 */
452 void SnapManager::guideConstrainedSnap(Geom::Point &p, SPGuide const &guideline) const
453 {
454 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
455 return;
456 }
458 if (!(object.ThisSnapperMightSnap() || snapprefs.getSnapToGuides())) {
459 return;
460 }
462 Inkscape::SnapCandidatePoint candidate(p, Inkscape::SNAPSOURCE_GUIDE_ORIGIN, Inkscape::SNAPTARGET_UNDEFINED);
464 // Snap to nodes or paths
465 SnappedConstraints sc;
466 Inkscape::Snapper::SnapConstraint cl(guideline.point_on_line, Geom::rot90(guideline.normal_to_line));
467 if (object.ThisSnapperMightSnap()) {
468 object.constrainedSnap(sc, candidate, Geom::OptRect(), cl, NULL);
469 }
471 // Snap to guides & grid lines
472 SnapperList snappers = getGridSnappers();
473 snappers.push_back(&guide);
474 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
475 (*i)->constrainedSnap(sc, candidate, Geom::OptRect(), cl, NULL);
476 }
478 Inkscape::SnappedPoint const s = findBestSnap(candidate, sc, false);
479 s.getPoint(p);
480 }
482 /**
483 * \brief Method for snapping sets of points while they are being transformed
484 *
485 * Method for snapping sets of points while they are being transformed, when using
486 * for example the selector tool. This method is for internal use only, and should
487 * not have to be called directly. Use freeSnapTransalation(), constrainedSnapScale(),
488 * etc. instead.
489 *
490 * This is what is being done in this method: transform each point, find out whether
491 * a free snap or constrained snap is more appropriate, do the snapping, calculate
492 * some metrics to quantify the snap "distance", and see if it's better than the
493 * previous snap. Finally, the best ("nearest") snap from all these points is returned.
494 *
495 * \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.
496 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
497 * \param constrained true if the snap is constrained, e.g. for stretching or for purely horizontal translation.
498 * \param constraint The direction or line along which snapping must occur, if 'constrained' is true; otherwise undefined.
499 * \param transformation_type Type of transformation to apply to points before trying to snap them.
500 * \param transformation Description of the transformation; details depend on the type.
501 * \param origin Origin of the transformation, if applicable.
502 * \param dim Dimension to which the transformation applies, if applicable.
503 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
504 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
505 */
507 Inkscape::SnappedPoint SnapManager::_snapTransformed(
508 std::vector<Inkscape::SnapCandidatePoint> const &points,
509 Geom::Point const &pointer,
510 bool constrained,
511 Inkscape::Snapper::SnapConstraint const &constraint,
512 Transformation transformation_type,
513 Geom::Point const &transformation,
514 Geom::Point const &origin,
515 Geom::Dim2 dim,
516 bool uniform) const
517 {
518 /* We have a list of points, which we are proposing to transform in some way. We need to see
519 ** if any of these points, when transformed, snap to anything. If they do, we return the
520 ** appropriate transformation with `true'; otherwise we return the original scale with `false'.
521 */
523 /* Quick check to see if we have any snappers that are enabled
524 ** Also used to globally disable all snapping
525 */
526 if (someSnapperMightSnap() == false || points.size() == 0) {
527 return Inkscape::SnappedPoint(pointer);
528 }
530 std::vector<Inkscape::SnapCandidatePoint> transformed_points;
531 Geom::Rect bbox;
533 long source_num = 0;
534 for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = points.begin(); i != points.end(); i++) {
536 /* Work out the transformed version of this point */
537 Geom::Point transformed = _transformPoint(*i, transformation_type, transformation, origin, dim, uniform);
539 // add the current transformed point to the box hulling all transformed points
540 if (i == points.begin()) {
541 bbox = Geom::Rect(transformed, transformed);
542 } else {
543 bbox.expandTo(transformed);
544 }
546 transformed_points.push_back(Inkscape::SnapCandidatePoint(transformed, (*i).getSourceType(), source_num));
547 source_num++;
548 }
550 /* The current best transformation */
551 Geom::Point best_transformation = transformation;
553 /* The current best metric for the best transformation; lower is better, NR_HUGE
554 ** means that we haven't snapped anything.
555 */
556 Geom::Point best_scale_metric(NR_HUGE, NR_HUGE);
557 Inkscape::SnappedPoint best_snapped_point;
558 g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point
559 g_assert(best_snapped_point.getAtIntersection() == false);
561 // Warnings for the devs
562 if (constrained && transformation_type == SCALE && !uniform) {
563 g_warning("Non-uniform constrained scaling is not supported!");
564 }
566 if (!constrained && transformation_type == ROTATE) {
567 // We do not yet allow for simultaneous rotation and scaling
568 g_warning("Unconstrained rotation is not supported!");
569 }
571 std::vector<Inkscape::SnapCandidatePoint>::iterator j = transformed_points.begin();
573 // std::cout << std::endl;
574 bool first_free_snap = true;
575 for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = points.begin(); i != points.end(); i++) {
577 /* Snap it */
578 Inkscape::SnappedPoint snapped_point;
579 Inkscape::Snapper::SnapConstraint dedicated_constraint = constraint;
580 Geom::Point const b = ((*i).getPoint() - origin); // vector to original point (not the transformed point! required for rotations!)
582 if (constrained) {
583 if (((transformation_type == SCALE || transformation_type == STRETCH) && uniform)) {
584 // When uniformly scaling, each point will have its own unique constraint line,
585 // running from the scaling origin to the original untransformed point. We will
586 // calculate that line here
587 dedicated_constraint = Inkscape::Snapper::SnapConstraint(origin, b);
588 } else if (transformation_type == ROTATE) {
589 // Geom::L2(b) is the radius of the circular constraint
590 dedicated_constraint = Inkscape::Snapper::SnapConstraint(origin, b, Geom::L2(b));
591 } else if (transformation_type == STRETCH) { // when non-uniform stretching {
592 dedicated_constraint = Inkscape::Snapper::SnapConstraint((*i).getPoint(), component_vectors[dim]);
593 } else if (transformation_type == TRANSLATE) {
594 // When doing a constrained translation, all points will move in the same direction, i.e.
595 // either horizontally or vertically. The lines along which they move are therefore all
596 // parallel, but might not be colinear. Therefore we will have to specify the point through
597 // which the constraint-line runs here, for each point individually. (we could also have done this
598 // earlier on, e.g. in seltrans.cpp but we're being lazy there and don't want to add an iteration loop)
599 dedicated_constraint = Inkscape::Snapper::SnapConstraint((*i).getPoint(), constraint.getDirection());
600 } // else: leave the original constraint, e.g. for skewing
601 snapped_point = constrainedSnap(*j, dedicated_constraint, bbox);
602 } else {
603 bool const c1 = fabs(b[Geom::X]) < 1e-6;
604 bool const c2 = fabs(b[Geom::Y]) < 1e-6;
605 if (transformation_type == SCALE && (c1 || c2) && !(c1 && c2)) {
606 // When scaling, a point aligned either horizontally or vertically with the origin can only
607 // move in that specific direction; therefore it should only snap in that direction, otherwise
608 // we will get snapped points with an invalid transformation
609 dedicated_constraint = Inkscape::Snapper::SnapConstraint(origin, component_vectors[c1]);
610 snapped_point = constrainedSnap(*j, dedicated_constraint, bbox);
611 } else {
612 // If we have a collection of SnapCandidatePoints, with mixed constrained snapping and free snapping
613 // requirements, then freeSnap might never see the SnapCandidatePoint with source_num == 0. The freeSnap()
614 // method in the object snapper depends on this, because only for source-num == 0 the target nodes will
615 // be collected. Therefore we enforce that the first SnapCandidatePoint that is to be freeSnapped always
616 // has source_num == 0;
617 // TODO: This is a bit ugly so fix this; do we need sourcenum for anything else? if we don't then get rid
618 // of it and explicitely communicate to the object snapper that this is a first point
619 if (first_free_snap) {
620 (*j).setSourceNum(0);
621 first_free_snap = false;
622 }
623 snapped_point = freeSnap(*j, bbox);
624 }
625 }
626 // std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl;
627 snapped_point.setPointerDistance(Geom::L2(pointer - (*i).getPoint()));
629 Geom::Point result;
631 if (snapped_point.getSnapped()) {
632 /* We snapped. Find the transformation that describes where the snapped point has
633 ** ended up, and also the metric for this transformation.
634 */
635 Geom::Point const a = snapped_point.getPoint() - origin; // vector to snapped point
636 //Geom::Point const b = (*i - origin); // vector to original point
638 switch (transformation_type) {
639 case TRANSLATE:
640 result = snapped_point.getPoint() - (*i).getPoint();
641 /* Consider the case in which a box is almost aligned with a grid in both
642 * horizontal and vertical directions. The distance to the intersection of
643 * the grid lines will always be larger then the distance to a single grid
644 * line. If we prefer snapping to an intersection instead of to a single
645 * grid line, then we cannot use "metric = Geom::L2(result)". Therefore the
646 * snapped distance will be used as a metric. Please note that the snapped
647 * distance is defined as the distance to the nearest line of the intersection,
648 * and not to the intersection itself!
649 */
650 // Only for translations, the relevant metric will be the real snapped distance,
651 // so we don't have to do anything special here
652 break;
653 case SCALE:
654 {
655 result = Geom::Point(NR_HUGE, NR_HUGE);
656 // If this point *i is horizontally or vertically aligned with
657 // the origin of the scaling, then it will scale purely in X or Y
658 // We can therefore only calculate the scaling in this direction
659 // and the scaling factor for the other direction should remain
660 // untouched (unless scaling is uniform of course)
661 for (int index = 0; index < 2; index++) {
662 if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
663 if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
664 result[index] = a[index] / b[index]; // then calculate it!
665 }
666 // we might leave result[1-index] = NR_HUGE
667 // if scaling didn't occur in the other direction
668 }
669 }
670 if (uniform) {
671 if (fabs(result[0]) < fabs(result[1])) {
672 result[1] = result[0];
673 } else {
674 result[0] = result[1];
675 }
676 }
677 // Compare the resulting scaling with the desired scaling
678 Geom::Point scale_metric = Geom::abs(result - transformation); // One or both of its components might be NR_HUGE
679 snapped_point.setSnapDistance(std::min(scale_metric[0], scale_metric[1]));
680 snapped_point.setSecondSnapDistance(std::max(scale_metric[0], scale_metric[1]));
681 break;
682 }
683 case STRETCH:
684 result = Geom::Point(NR_HUGE, NR_HUGE);
685 if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
686 result[dim] = a[dim] / b[dim];
687 result[1-dim] = uniform ? result[dim] : 1;
688 } else { // STRETCHING might occur for this point, but only when the stretching is uniform
689 if (uniform && fabs(b[1-dim]) > 1e-6) {
690 result[1-dim] = a[1-dim] / b[1-dim];
691 result[dim] = result[1-dim];
692 }
693 }
694 // Store the metric for this transformation as a virtual distance
695 snapped_point.setSnapDistance(std::abs(result[dim] - transformation[dim]));
696 snapped_point.setSecondSnapDistance(NR_HUGE);
697 break;
698 case SKEW:
699 result[0] = (snapped_point.getPoint()[dim] - ((*i).getPoint())[dim]) / b[1 - dim]; // skew factor
700 result[1] = transformation[1]; // scale factor
701 // Store the metric for this transformation as a virtual distance
702 snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
703 snapped_point.setSecondSnapDistance(NR_HUGE);
704 break;
705 case ROTATE:
706 // a is vector to snapped point; b is vector to original point; now lets calculate angle between a and b
707 result[0] = atan2(Geom::dot(Geom::rot90(b), a), Geom::dot(b, a));
708 result[1] = result[1]; // how else should we store an angle in a point ;-)
709 // Store the metric for this transformation as a virtual distance (we're storing an angle)
710 snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
711 snapped_point.setSecondSnapDistance(NR_HUGE);
712 break;
713 default:
714 g_assert_not_reached();
715 }
717 if (best_snapped_point.isOtherSnapBetter(snapped_point, true)) {
718 best_transformation = result;
719 best_snapped_point = snapped_point;
720 }
721 }
723 j++;
724 }
726 Geom::Coord best_metric;
727 if (transformation_type == SCALE) {
728 // When scaling, don't ever exit with one of scaling components set to NR_HUGE
729 for (int index = 0; index < 2; index++) {
730 if (best_transformation[index] == NR_HUGE) {
731 if (uniform && best_transformation[1-index] < NR_HUGE) {
732 best_transformation[index] = best_transformation[1-index];
733 } else {
734 best_transformation[index] = transformation[index];
735 }
736 }
737 }
738 }
740 best_metric = best_snapped_point.getSnapDistance();
741 best_snapped_point.setTransformation(best_transformation);
742 // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
743 // These rounding errors might be caused by NRRects, see bug #1584301
744 best_snapped_point.setSnapDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
745 return best_snapped_point;
746 }
749 /**
750 * \brief Apply a translation to a set of points and try to snap freely in 2 degrees-of-freedom
751 *
752 * \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.
753 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
754 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred
755 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
756 */
758 Inkscape::SnappedPoint SnapManager::freeSnapTranslate(std::vector<Inkscape::SnapCandidatePoint> const &p,
759 Geom::Point const &pointer,
760 Geom::Point const &tr) const
761 {
762 if (p.size() == 1) {
763 Geom::Point pt = _transformPoint(p.at(0), TRANSLATE, tr, Geom::Point(0,0), Geom::X, false);
764 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
765 }
767 return _snapTransformed(p, pointer, false, Geom::Point(0,0), TRANSLATE, tr, Geom::Point(0,0), Geom::X, false);
768 }
770 /**
771 * \brief Apply a translation to a set of points and try to snap along a constraint
772 *
773 * \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.
774 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
775 * \param constraint The direction or line along which snapping must occur.
776 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred.
777 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
778 */
780 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslate(std::vector<Inkscape::SnapCandidatePoint> const &p,
781 Geom::Point const &pointer,
782 Inkscape::Snapper::SnapConstraint const &constraint,
783 Geom::Point const &tr) const
784 {
785 if (p.size() == 1) {
786 Geom::Point pt = _transformPoint(p.at(0), TRANSLATE, tr, Geom::Point(0,0), Geom::X, false);
787 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
788 }
790 return _snapTransformed(p, pointer, true, constraint, TRANSLATE, tr, Geom::Point(0,0), Geom::X, false);
791 }
794 /**
795 * \brief Apply a scaling to a set of points and try to snap freely in 2 degrees-of-freedom
796 *
797 * \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.
798 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
799 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
800 * \param o Origin of the scaling
801 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
802 */
804 Inkscape::SnappedPoint SnapManager::freeSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
805 Geom::Point const &pointer,
806 Geom::Scale const &s,
807 Geom::Point const &o) const
808 {
809 if (p.size() == 1) {
810 Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
811 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
812 }
814 return _snapTransformed(p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
815 }
818 /**
819 * \brief Apply a scaling to a set of points and snap such that the aspect ratio of the selection is preserved
820 *
821 * \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.
822 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
823 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
824 * \param o Origin of the scaling
825 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
826 */
828 Inkscape::SnappedPoint SnapManager::constrainedSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
829 Geom::Point const &pointer,
830 Geom::Scale const &s,
831 Geom::Point const &o) const
832 {
833 // When constrained scaling, only uniform scaling is supported.
834 if (p.size() == 1) {
835 Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
836 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
837 }
839 return _snapTransformed(p, pointer, true, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
840 }
842 /**
843 * \brief Apply a stretch to a set of points and snap such that the direction of the stretch is preserved
844 *
845 * \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.
846 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
847 * \param s Proposed stretch; the final stretch can only be calculated after snapping has occurred
848 * \param o Origin of the stretching
849 * \param d Dimension in which to apply proposed stretch.
850 * \param u true if the stretch should be uniform (i.e. to be applied equally in both dimensions)
851 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
852 */
854 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(std::vector<Inkscape::SnapCandidatePoint> const &p,
855 Geom::Point const &pointer,
856 Geom::Coord const &s,
857 Geom::Point const &o,
858 Geom::Dim2 d,
859 bool u) const
860 {
861 if (p.size() == 1) {
862 Geom::Point pt = _transformPoint(p.at(0), STRETCH, Geom::Point(s, s), o, d, u);
863 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
864 }
866 return _snapTransformed(p, pointer, true, Geom::Point(0,0), STRETCH, Geom::Point(s, s), o, d, u);
867 }
869 /**
870 * \brief Apply a skew to a set of points and snap such that the direction of the skew is preserved
871 *
872 * \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.
873 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
874 * \param constraint The direction or line along which snapping must occur.
875 * \param s Proposed skew; the final skew can only be calculated after snapping has occurred
876 * \param o Origin of the proposed skew
877 * \param d Dimension in which to apply proposed skew.
878 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
879 */
881 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(std::vector<Inkscape::SnapCandidatePoint> const &p,
882 Geom::Point const &pointer,
883 Inkscape::Snapper::SnapConstraint const &constraint,
884 Geom::Point const &s,
885 Geom::Point const &o,
886 Geom::Dim2 d) const
887 {
888 // "s" contains skew factor in s[0], and scale factor in s[1]
890 // Snapping the nodes of the bounding box of a selection that is being transformed, will only work if
891 // the transformation of the bounding box is equal to the transformation of the individual nodes. This is
892 // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
893 // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
894 // of bounding boxes is not allowed here.
895 if (p.size() > 0) {
896 g_assert(!(p.at(0).getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY));
897 }
899 if (p.size() == 1) {
900 Geom::Point pt = _transformPoint(p.at(0), SKEW, s, o, d, false);
901 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
902 }
904 return _snapTransformed(p, pointer, true, constraint, SKEW, s, o, d, false);
905 }
907 /**
908 * \brief Apply a rotation to a set of points and snap, without scaling
909 *
910 * \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.
911 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
912 * \param angle Proposed rotation (in radians); the final rotation can only be calculated after snapping has occurred
913 * \param o Origin of the rotation
914 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
915 */
917 Inkscape::SnappedPoint SnapManager::constrainedSnapRotate(std::vector<Inkscape::SnapCandidatePoint> const &p,
918 Geom::Point const &pointer,
919 Geom::Coord const &angle,
920 Geom::Point const &o) const
921 {
922 // Snapping the nodes of the bounding box of a selection that is being transformed, will only work if
923 // the transformation of the bounding box is equal to the transformation of the individual nodes. This is
924 // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
925 // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
926 // of bounding boxes is not allowed here.
928 if (p.size() == 1) {
929 Geom::Point pt = _transformPoint(p.at(0), ROTATE, Geom::Point(angle, angle), o, Geom::X, false);
930 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
931 }
933 return _snapTransformed(p, pointer, true, Geom::Point(0,0), ROTATE, Geom::Point(angle, angle), o, Geom::X, false);
935 }
937 /**
938 * \brief Given a set of possible snap targets, find the best target (which is not necessarily
939 * also the nearest target), and show the snap indicator if requested
940 *
941 * \param p Source point to be snapped
942 * \param sc A structure holding all snap targets that have been found so far
943 * \param constrained True if the snap is constrained, e.g. for stretching or for purely horizontal translation.
944 * \param noCurves If true, then do consider snapping to intersections of curves, but not to the curves themselves
945 * \param allowOffScreen If true, then snapping to points which are off the screen is allowed (needed for example when pasting to the grid)
946 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
947 */
949 Inkscape::SnappedPoint SnapManager::findBestSnap(Inkscape::SnapCandidatePoint const &p,
950 SnappedConstraints const &sc,
951 bool constrained,
952 bool noCurves,
953 bool allowOffScreen) const
954 {
957 /*
958 std::cout << "Type and number of snapped constraints: " << std::endl;
959 std::cout << " Points : " << sc.points.size() << std::endl;
960 std::cout << " Lines : " << sc.lines.size() << std::endl;
961 std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
962 std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
963 std::cout << " Curves : " << sc.curves.size()<< std::endl;
964 */
966 // Store all snappoints
967 std::list<Inkscape::SnappedPoint> sp_list;
969 // search for the closest snapped point
970 Inkscape::SnappedPoint closestPoint;
971 if (getClosestSP(sc.points, closestPoint)) {
972 sp_list.push_back(closestPoint);
973 }
975 // search for the closest snapped curve
976 if (!noCurves) {
977 Inkscape::SnappedCurve closestCurve;
978 if (getClosestCurve(sc.curves, closestCurve)) {
979 sp_list.push_back(Inkscape::SnappedPoint(closestCurve));
980 }
981 }
983 if (snapprefs.getSnapIntersectionCS()) {
984 // search for the closest snapped intersection of curves
985 Inkscape::SnappedPoint closestCurvesIntersection;
986 if (getClosestIntersectionCS(sc.curves, p.getPoint(), closestCurvesIntersection, _desktop->dt2doc())) {
987 closestCurvesIntersection.setSource(p.getSourceType());
988 sp_list.push_back(closestCurvesIntersection);
989 }
990 }
992 // search for the closest snapped grid line
993 Inkscape::SnappedLine closestGridLine;
994 if (getClosestSL(sc.grid_lines, closestGridLine)) {
995 sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
996 }
998 // search for the closest snapped guide line
999 Inkscape::SnappedLine closestGuideLine;
1000 if (getClosestSL(sc.guide_lines, closestGuideLine)) {
1001 sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
1002 }
1004 // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
1005 // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
1007 // When doing a constrained snap however, we're already at an intersection of the constrained line and
1008 // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
1009 // no need to look for additional intersections
1010 if (!constrained) {
1011 // search for the closest snapped intersection of grid lines
1012 Inkscape::SnappedPoint closestGridPoint;
1013 if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
1014 closestGridPoint.setSource(p.getSourceType());
1015 closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
1016 sp_list.push_back(closestGridPoint);
1017 }
1019 // search for the closest snapped intersection of guide lines
1020 Inkscape::SnappedPoint closestGuidePoint;
1021 if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
1022 closestGuidePoint.setSource(p.getSourceType());
1023 closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
1024 sp_list.push_back(closestGuidePoint);
1025 }
1027 // search for the closest snapped intersection of grid with guide lines
1028 if (snapprefs.getSnapIntersectionGG()) {
1029 Inkscape::SnappedPoint closestGridGuidePoint;
1030 if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
1031 closestGridGuidePoint.setSource(p.getSourceType());
1032 closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
1033 sp_list.push_back(closestGridGuidePoint);
1034 }
1035 }
1036 }
1038 // now let's see which snapped point gets a thumbs up
1039 Inkscape::SnappedPoint bestSnappedPoint(p.getPoint());
1040 // std::cout << "Finding the best snap..." << std::endl;
1041 for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
1042 // std::cout << "sp = " << (*i).getPoint() << " | source = " << (*i).getSource() << " | target = " << (*i).getTarget();
1043 bool onScreen = _desktop->get_display_area().contains((*i).getPoint());
1044 if (onScreen || allowOffScreen) { // Only snap to points which are not off the screen
1045 if ((*i).getSnapDistance() <= (*i).getTolerance()) { // Only snap to points within snapping range
1046 // if it's the first point, or if it is closer than the best snapped point so far
1047 if (i == sp_list.begin() || bestSnappedPoint.isOtherSnapBetter(*i, false)) {
1048 // then prefer this point over the previous one
1049 bestSnappedPoint = *i;
1050 }
1051 }
1052 }
1053 // std::cout << std::endl;
1054 }
1056 // Update the snap indicator, if requested
1057 if (_snapindicator) {
1058 if (bestSnappedPoint.getSnapped()) {
1059 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
1060 } else {
1061 _desktop->snapindicator->remove_snaptarget();
1062 }
1063 }
1065 // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl;
1066 return bestSnappedPoint;
1067 }
1069 /// Convenience shortcut when there is only one item to ignore
1070 void SnapManager::setup(SPDesktop const *desktop,
1071 bool snapindicator,
1072 SPItem const *item_to_ignore,
1073 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1074 SPGuide *guide_to_ignore)
1075 {
1076 g_assert(desktop != NULL);
1077 _items_to_ignore.clear();
1078 _items_to_ignore.push_back(item_to_ignore);
1079 _desktop = desktop;
1080 _snapindicator = snapindicator;
1081 _unselected_nodes = unselected_nodes;
1082 _guide_to_ignore = guide_to_ignore;
1083 }
1085 /**
1086 * \brief Prepare the snap manager for the actual snapping, which includes building a list of snap targets
1087 * to ignore and toggling the snap indicator
1088 *
1089 * There are two overloaded setup() methods, of which the other one only allows for a single item to be ignored
1090 * whereas this one will take a list of items to ignore
1091 *
1092 * \param desktop Reference to the desktop to which this snap manager is attached
1093 * \param snapindicator If true then a snap indicator will be displayed automatically (when enabled in the preferences)
1094 * \param items_to_ignore These items will not be snapped to, e.g. the items that are currently being dragged. This avoids "self-snapping"
1095 * \param unselected_nodes Stationary nodes of the path that is currently being edited in the node tool and
1096 * that can be snapped too. Nodes not in this list will not be snapped to, to avoid "self-snapping". Of each
1097 * unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored
1098 * \param guide_to_ignore Guide that is currently being dragged and should not be snapped to
1099 */
1101 void SnapManager::setup(SPDesktop const *desktop,
1102 bool snapindicator,
1103 std::vector<SPItem const *> &items_to_ignore,
1104 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1105 SPGuide *guide_to_ignore)
1106 {
1107 g_assert(desktop != NULL);
1108 _items_to_ignore = items_to_ignore;
1109 _desktop = desktop;
1110 _snapindicator = snapindicator;
1111 _unselected_nodes = unselected_nodes;
1112 _guide_to_ignore = guide_to_ignore;
1113 }
1115 /// Setup, taking the list of items to ignore from the desktop's selection.
1116 void SnapManager::setupIgnoreSelection(SPDesktop const *desktop,
1117 bool snapindicator,
1118 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1119 SPGuide *guide_to_ignore)
1120 {
1121 _desktop = desktop;
1122 _snapindicator = snapindicator;
1123 _unselected_nodes = unselected_nodes;
1124 _guide_to_ignore = guide_to_ignore;
1125 _items_to_ignore.clear();
1127 Inkscape::Selection *sel = _desktop->selection;
1128 GSList const *items = sel->itemList();
1129 for (GSList *i = const_cast<GSList*>(items); i; i = i->next) {
1130 _items_to_ignore.push_back(static_cast<SPItem const *>(i->data));
1131 }
1132 }
1134 SPDocument *SnapManager::getDocument() const
1135 {
1136 return _named_view->document;
1137 }
1139 /**
1140 * \brief Takes an untransformed point, applies the given transformation, and returns the transformed point. Eliminates lots of duplicated code
1141 *
1142 * \param p The untransformed position of the point, paired with an identifier of the type of the snap source.
1143 * \param transformation_type Type of transformation to apply.
1144 * \param transformation Mathematical description of the transformation; details depend on the type.
1145 * \param origin Origin of the transformation, if applicable.
1146 * \param dim Dimension to which the transformation applies, if applicable.
1147 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
1148 * \return The position of the point after transformation
1149 */
1151 Geom::Point SnapManager::_transformPoint(Inkscape::SnapCandidatePoint const &p,
1152 Transformation const transformation_type,
1153 Geom::Point const &transformation,
1154 Geom::Point const &origin,
1155 Geom::Dim2 const dim,
1156 bool const uniform) const
1157 {
1158 /* Work out the transformed version of this point */
1159 Geom::Point transformed;
1160 switch (transformation_type) {
1161 case TRANSLATE:
1162 transformed = p.getPoint() + transformation;
1163 break;
1164 case SCALE:
1165 transformed = (p.getPoint() - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
1166 break;
1167 case STRETCH:
1168 {
1169 Geom::Scale s(1, 1);
1170 if (uniform)
1171 s[Geom::X] = s[Geom::Y] = transformation[dim];
1172 else {
1173 s[dim] = transformation[dim];
1174 s[1 - dim] = 1;
1175 }
1176 transformed = ((p.getPoint() - origin) * s) + origin;
1177 break;
1178 }
1179 case SKEW:
1180 // Apply the skew factor
1181 transformed[dim] = (p.getPoint())[dim] + transformation[0] * ((p.getPoint())[1 - dim] - origin[1 - dim]);
1182 // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
1183 // Apply that scale factor here
1184 transformed[1-dim] = (p.getPoint() - origin)[1 - dim] * transformation[1] + origin[1 - dim];
1185 break;
1186 case ROTATE:
1187 // for rotations: transformation[0] stores the angle in radians
1188 transformed = (p.getPoint() - origin) * Geom::Rotate(transformation[0]) + origin;
1189 break;
1190 default:
1191 g_assert_not_reached();
1192 }
1194 return transformed;
1195 }
1197 /**
1198 * \brief Mark the location of the snap source (not the snap target!) on the canvas by drawing a symbol
1199 *
1200 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
1201 * \param p The transformed position of the source point, paired with an identifier of the type of the snap source.
1202 */
1204 void SnapManager::_displaySnapsource(Inkscape::SnapCandidatePoint const &p) const {
1206 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
1207 if (prefs->getBool("/options/snapclosestonly/value")) {
1208 bool p_is_a_node = p.getSourceType() & Inkscape::SNAPSOURCE_NODE_CATEGORY;
1209 bool p_is_a_bbox = p.getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY;
1211 if (snapprefs.getSnapEnabledGlobally() && ((p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) {
1212 _desktop->snapindicator->set_new_snapsource(p);
1213 } else {
1214 _desktop->snapindicator->remove_snapsource();
1215 }
1216 }
1217 }
1219 /*
1220 Local Variables:
1221 mode:c++
1222 c-file-style:"stroustrup"
1223 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1224 indent-tabs-mode:nil
1225 fill-column:99
1226 End:
1227 */
1228 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :