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) 1999-2009 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 "sp-guide.h"
34 #include "preferences.h"
35 #include "event-context.h"
36 using std::vector;
38 /**
39 * Construct a SnapManager for a SPNamedView.
40 *
41 * \param v `Owning' SPNamedView.
42 */
44 SnapManager::SnapManager(SPNamedView const *v) :
45 guide(this, 0),
46 object(this, 0),
47 snapprefs(),
48 _named_view(v)
49 {
50 }
52 /**
53 * \brief Return a list of snappers
54 *
55 * Inkscape snaps to objects, grids, and guides. For each of these snap targets a
56 * separate class is used, which has been derived from the base Snapper class. The
57 * getSnappers() method returns a list of pointers to instances of this class. This
58 * list contains exactly one instance of the guide snapper and of the object snapper
59 * class, but any number of grid snappers (because each grid has its own snapper
60 * instance)
61 *
62 * \return List of snappers that we use.
63 */
64 SnapManager::SnapperList
65 SnapManager::getSnappers() const
66 {
67 SnapManager::SnapperList s;
68 s.push_back(&guide);
69 s.push_back(&object);
71 SnapManager::SnapperList gs = getGridSnappers();
72 s.splice(s.begin(), gs);
74 return s;
75 }
77 /**
78 * \brief Return a list of gridsnappers
79 *
80 * Each grid has its own instance of the snapper class. This way snapping can
81 * be enabled per grid individually. A list will be returned containing the
82 * pointers to these instances, but only for grids that are being displayed
83 * and for which snapping is enabled.
84 *
85 * \return List of gridsnappers that we use.
86 */
87 SnapManager::SnapperList
88 SnapManager::getGridSnappers() const
89 {
90 SnapperList s;
92 if (_desktop && _desktop->gridsEnabled() && snapprefs.getSnapToGrids()) {
93 for ( GSList const *l = _named_view->grids; l != NULL; l = l->next) {
94 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
95 s.push_back(grid->snapper);
96 }
97 }
99 return s;
100 }
102 /**
103 * \brief Return true if any snapping might occur, whether its to grids, guides or objects
104 *
105 * Each snapper instance handles its own snapping target, e.g. grids, guides or
106 * objects. This method iterates through all these snapper instances and returns
107 * true if any of the snappers might possible snap, considering only the relevant
108 * snapping preferences.
109 *
110 * \return true if one of the snappers will try to snap to something.
111 */
113 bool SnapManager::someSnapperMightSnap() const
114 {
115 if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) {
116 return false;
117 }
119 SnapperList const s = getSnappers();
120 SnapperList::const_iterator i = s.begin();
121 while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
122 i++;
123 }
125 return (i != s.end());
126 }
128 /**
129 * \return true if one of the grids might be snapped to.
130 */
132 bool SnapManager::gridSnapperMightSnap() const
133 {
134 if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) {
135 return false;
136 }
138 SnapperList const s = getGridSnappers();
139 SnapperList::const_iterator i = s.begin();
140 while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
141 i++;
142 }
144 return (i != s.end());
145 }
147 /**
148 * \brief Try to snap a point to grids, guides or objects.
149 *
150 * Try to snap a point to grids, guides or objects, in two degrees-of-freedom,
151 * i.e. snap in any direction on the two dimensional canvas to the nearest
152 * snap target. freeSnapReturnByRef() is equal in snapping behavior to
153 * freeSnap(), but the former returns the snapped point trough the referenced
154 * parameter p. This parameter p initially contains the position of the snap
155 * source and will we overwritten by the target position if snapping has occurred.
156 * This makes snapping transparent to the calling code. If this is not desired
157 * because either the calling code must know whether snapping has occurred, or
158 * because the original position should not be touched, then freeSnap() should be
159 * called instead.
160 *
161 * PS: SnapManager::setup() must have been called before calling this method,
162 * but only once for a set of points
163 *
164 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
165 * \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred
166 * \param source_type Detailed description of the source type, will be used by the snap indicator
167 * \param first_point If true then this point is the first one from a set of points, all from the same selection and having the same transformation
168 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
169 */
171 void SnapManager::freeSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
172 Geom::Point &p,
173 Inkscape::SnapSourceType const source_type,
174 bool first_point,
175 Geom::OptRect const &bbox_to_snap) const
176 {
177 //TODO: PointType and source_type are somewhat redundant; can't we get rid of the point_type parameter?
178 Inkscape::SnappedPoint const s = freeSnap(point_type, p, source_type, first_point, 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 point_type Category of points to which the source point belongs: node, guide or bounding box
195 * \param p Current position of the snap source
196 * \param source_type Detailed description of the source type, will be used by the snap indicator
197 * \param first_point If true then this point is the first one from a set of points, all from the same selection and having the same transformation
198 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
199 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
200 */
203 Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::SnapPreferences::PointType point_type,
204 Geom::Point const &p,
205 Inkscape::SnapSourceType const &source_type,
206 bool first_point,
207 Geom::OptRect const &bbox_to_snap) const
208 {
209 if (!someSnapperMightSnap()) {
210 return Inkscape::SnappedPoint(p, source_type, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
211 }
213 std::vector<SPItem const *> *items_to_ignore;
214 if (_item_to_ignore) { // If we have only a single item to ignore
215 // then build a list containing this single item;
216 // This single-item list will prevail over any other _items_to_ignore list, should that exist
217 items_to_ignore = new std::vector<SPItem const *>;
218 items_to_ignore->push_back(_item_to_ignore);
219 } else {
220 items_to_ignore = _items_to_ignore;
221 }
223 SnappedConstraints sc;
224 SnapperList const snappers = getSnappers();
226 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
227 (*i)->freeSnap(sc, point_type, p, source_type, first_point, bbox_to_snap, items_to_ignore, _unselected_nodes);
228 }
230 if (_item_to_ignore) {
231 delete items_to_ignore;
232 }
234 return findBestSnap(p, source_type, sc, false);
235 }
237 /**
238 * \brief Snap to the closest multiple of a grid pitch
239 *
240 * When pasting, we would like to snap to the grid. Problem is that we don't know which
241 * nodes were aligned to the grid at the time of copying, so we don't know which nodes
242 * to snap. If we'd snap an unaligned node to the grid, previously aligned nodes would
243 * become unaligned. That's undesirable. Instead we will make sure that the offset
244 * between the source and its pasted copy is a multiple of the grid pitch. If the source
245 * was aligned, then the copy will therefore also be aligned.
246 *
247 * PS: Whether we really find a multiple also depends on the snapping range! Most users
248 * will have "always snap" enabled though, in which case a multiple will always be found.
249 * PS2: When multiple grids are present then the result will become ambiguous. There is no
250 * way to control to which grid this method will snap.
251 *
252 * \param t Vector that represents the offset of the pasted copy with respect to the original
253 * \return Offset vector after snapping to the closest multiple of a grid pitch
254 */
256 Geom::Point SnapManager::multipleOfGridPitch(Geom::Point const &t) const
257 {
258 if (!snapprefs.getSnapEnabledGlobally()) // No need to check for snapprefs.getSnapPostponedGlobally() here
259 return t;
261 if (_desktop && _desktop->gridsEnabled()) {
262 bool success = false;
263 Geom::Point nearest_multiple;
264 Geom::Coord nearest_distance = NR_HUGE;
266 // It will snap to the grid for which we find the closest snap. This might be a different
267 // grid than to which the objects were initially aligned. I don't see an easy way to fix
268 // this, so when using multiple grids one can get unexpected results
270 // Cannot use getGridSnappers() because we need both the grids AND their snappers
271 // Therefore we iterate through all grids manually
272 for (GSList const *l = _named_view->grids; l != NULL; l = l->next) {
273 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
274 const Inkscape::Snapper* snapper = grid->snapper;
275 if (snapper && snapper->ThisSnapperMightSnap()) {
276 // To find the nearest multiple of the grid pitch for a given translation t, we
277 // will use the grid snapper. Simply snapping the value t to the grid will do, but
278 // only if the origin of the grid is at (0,0). If it's not then compensate for this
279 // in the translation t
280 Geom::Point const t_offset = t + grid->origin;
281 SnappedConstraints sc;
282 // Only the first three parameters are being used for grid snappers
283 snapper->freeSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_NODE, t_offset, Inkscape::SNAPSOURCE_UNDEFINED, TRUE, Geom::OptRect(), NULL, NULL);
284 // Find the best snap for this grid, including intersections of the grid-lines
285 Inkscape::SnappedPoint s = findBestSnap(t_offset, Inkscape::SNAPSOURCE_UNDEFINED, sc, false);
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 }
293 }
294 }
296 if (success)
297 return nearest_multiple;
298 }
300 return t;
301 }
303 /**
304 * \brief Try to snap a point along a constraint line to grids, guides or objects.
305 *
306 * Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
307 * i.e. snap in a specific direction on the two dimensional canvas to the nearest
308 * snap target.
309 *
310 * constrainedSnapReturnByRef() is equal in snapping behavior to
311 * constrainedSnap(), but the former returns the snapped point trough the referenced
312 * parameter p. This parameter p initially contains the position of the snap
313 * source and will we overwritten by the target position if snapping has occurred.
314 * This makes snapping transparent to the calling code. If this is not desired
315 * because either the calling code must know whether snapping has occurred, or
316 * because the original position should not be touched, then constrainedSnap() should
317 * be called instead.
318 *
319 * PS: SnapManager::setup() must have been called before calling this method,
320 * but only once for a set of points
321 *
322 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
323 * \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred
324 * \param source_type Detailed description of the source type, will be used by the snap indicator
325 * \param constraint The direction or line along which snapping must occur
326 * \param first_point If true then this point is the first one from a set of points, all from the same selection and having the same transformation
327 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
328 */
330 void SnapManager::constrainedSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
331 Geom::Point &p,
332 Inkscape::SnapSourceType const source_type,
333 Inkscape::Snapper::ConstraintLine const &constraint,
334 bool first_point,
335 Geom::OptRect const &bbox_to_snap) const
336 {
337 Inkscape::SnappedPoint const s = constrainedSnap(point_type, p, source_type, constraint, first_point, bbox_to_snap);
338 s.getPoint(p);
339 }
341 /**
342 * \brief Try to snap a point along a constraint line to grids, guides or objects.
343 *
344 * Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
345 * i.e. snap in a specific direction on the two dimensional canvas to the nearest
346 * snap target. constrainedSnap is equal in snapping behavior to
347 * constrainedSnapReturnByRef(). Please read the comments of the latter for more details.
348 *
349 * PS: SnapManager::setup() must have been called before calling this method,
350 * but only once for a set of points
351 *
352 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
353 * \param p Current position of the snap source
354 * \param source_type Detailed description of the source type, will be used by the snap indicator
355 * \param constraint The direction or line along which snapping must occur
356 * \param first_point If true then this point is the first one from a set of points, all from the same selection and having the same transformation
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::SnapPreferences::PointType point_type,
361 Geom::Point const &p,
362 Inkscape::SnapSourceType const &source_type,
363 Inkscape::Snapper::ConstraintLine const &constraint,
364 bool first_point,
365 Geom::OptRect const &bbox_to_snap) const
366 {
367 if (!someSnapperMightSnap()) {
368 return Inkscape::SnappedPoint(p, source_type, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
369 }
371 std::vector<SPItem const *> *items_to_ignore;
372 if (_item_to_ignore) { // If we have only a single item to ignore
373 // then build a list containing this single item;
374 // This single-item list will prevail over any other _items_to_ignore list, should that exist
375 items_to_ignore = new std::vector<SPItem const *>;
376 items_to_ignore->push_back(_item_to_ignore);
377 } else {
378 items_to_ignore = _items_to_ignore;
379 }
381 Geom::Point pp = constraint.projection(p);
383 SnappedConstraints sc;
384 SnapperList const snappers = getSnappers();
385 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
386 (*i)->constrainedSnap(sc, point_type, pp, source_type, first_point, bbox_to_snap, constraint, items_to_ignore);
387 }
389 if (_item_to_ignore) {
390 delete items_to_ignore;
391 }
393 return findBestSnap(p, source_type, sc, true);
394 }
396 /**
397 * \brief Try to snap a point of a guide to another guide or to a node
398 *
399 * Try to snap a point of a guide to another guide or to a node in two degrees-
400 * of-freedom, i.e. snap in any direction on the two dimensional canvas to the
401 * nearest snap target. This method is used when dragging or rotating a guide
402 *
403 * PS: SnapManager::setup() must have been called before calling this method,
404 *
405 * \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
406 * \param guide_normal Vector normal to the guide line
407 */
408 void SnapManager::guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const
409 {
410 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
411 return;
412 }
414 if (!(object.GuidesMightSnap() || snapprefs.getSnapToGuides())) {
415 return;
416 }
418 Inkscape::SnapSourceType source_type = Inkscape::SNAPSOURCE_GUIDE_ORIGIN;
419 if (drag_type == SP_DRAG_ROTATE) {
420 source_type = Inkscape::SNAPSOURCE_GUIDE;
421 }
423 // Snap to nodes
424 SnappedConstraints sc;
425 if (object.GuidesMightSnap()) {
426 object.guideFreeSnap(sc, p, guide_normal);
427 }
429 // Snap to guides & grid lines
430 SnapperList snappers = getGridSnappers();
431 snappers.push_back(&guide);
432 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
433 (*i)->freeSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, source_type, true, Geom::OptRect(), NULL, NULL);
434 }
436 // Snap to intersections of curves, but not to the curves themselves! (see _snapTranslatingGuideToNodes in object-snapper.cpp)
437 Inkscape::SnappedPoint const s = findBestSnap(p, source_type, sc, false, true);
439 s.getPoint(p);
440 }
442 /**
443 * \brief Try to snap a point on a guide to the intersection with another guide or a path
444 *
445 * Try to snap a point on a guide to the intersection of that guide with another
446 * guide or with a path. The snapped point will lie somewhere on the guide-line,
447 * making this is a constrained snap, i.e. in only one degree-of-freedom.
448 * This method is used when dragging the origin of the guide along the guide itself.
449 *
450 * PS: SnapManager::setup() must have been called before calling this method,
451 *
452 * \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
453 * \param guide_normal Vector normal to the guide line
454 */
456 void SnapManager::guideConstrainedSnap(Geom::Point &p, SPGuide const &guideline) const
457 {
458 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
459 return;
460 }
462 if (!(object.ThisSnapperMightSnap() || snapprefs.getSnapToGuides())) {
463 return;
464 }
466 Inkscape::SnapSourceType source_type = Inkscape::SNAPSOURCE_GUIDE_ORIGIN;
468 // Snap to nodes or paths
469 SnappedConstraints sc;
470 Inkscape::Snapper::ConstraintLine cl(guideline.point_on_line, Geom::rot90(guideline.normal_to_line));
471 if (object.ThisSnapperMightSnap()) {
472 object.constrainedSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, source_type, true, Geom::OptRect(), cl, NULL);
473 }
475 // Snap to guides & grid lines
476 SnapperList snappers = getGridSnappers();
477 snappers.push_back(&guide);
478 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
479 (*i)->constrainedSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, source_type, true, Geom::OptRect(), cl, NULL);
480 }
482 Inkscape::SnappedPoint const s = findBestSnap(p, source_type, sc, false);
483 s.getPoint(p);
484 }
486 /**
487 * \brief Method for snapping sets of points while they are being transformed
488 *
489 * Method for snapping sets of points while they are being transformed, when using
490 * for example the selector tool. This method is for internal use only, and should
491 * not have to be called directly. Use freeSnapTransalation(), constrainedSnapScale(),
492 * etc. instead.
493 *
494 * This is what is being done in this method: transform each point, find out whether
495 * a free snap or constrained snap is more appropriate, do the snapping, calculate
496 * some metrics to quantify the snap "distance", and see if it's better than the
497 * previous snap. Finally, the best ("nearest") snap from all these points is returned.
498 *
499 * \param type Category of points to which the source point belongs: node or bounding box.
500 * \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.
501 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
502 * \param constrained true if the snap is constrained, e.g. for stretching or for purely horizontal translation.
503 * \param constraint The direction or line along which snapping must occur, if 'constrained' is true; otherwise undefined.
504 * \param transformation_type Type of transformation to apply to points before trying to snap them.
505 * \param transformation Description of the transformation; details depend on the type.
506 * \param origin Origin of the transformation, if applicable.
507 * \param dim Dimension to which the transformation applies, if applicable.
508 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
509 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
510 */
512 Inkscape::SnappedPoint SnapManager::_snapTransformed(
513 Inkscape::SnapPreferences::PointType type,
514 std::vector<std::pair<Geom::Point, int> > const &points,
515 Geom::Point const &pointer,
516 bool constrained,
517 Inkscape::Snapper::ConstraintLine const &constraint,
518 Transformation transformation_type,
519 Geom::Point const &transformation,
520 Geom::Point const &origin,
521 Geom::Dim2 dim,
522 bool uniform) const
523 {
524 /* We have a list of points, which we are proposing to transform in some way. We need to see
525 ** if any of these points, when transformed, snap to anything. If they do, we return the
526 ** appropriate transformation with `true'; otherwise we return the original scale with `false'.
527 */
529 /* Quick check to see if we have any snappers that are enabled
530 ** Also used to globally disable all snapping
531 */
532 if (someSnapperMightSnap() == false) {
533 return Inkscape::SnappedPoint();
534 }
536 std::vector<std::pair<Geom::Point, int> > transformed_points;
537 Geom::Rect bbox;
539 for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = points.begin(); i != points.end(); i++) {
541 /* Work out the transformed version of this point */
542 Geom::Point transformed = _transformPoint(*i, transformation_type, transformation, origin, dim, uniform);
544 // add the current transformed point to the box hulling all transformed points
545 if (i == points.begin()) {
546 bbox = Geom::Rect(transformed, transformed);
547 } else {
548 bbox.expandTo(transformed);
549 }
551 transformed_points.push_back(std::make_pair(transformed, (*i).second));
552 }
554 /* The current best transformation */
555 Geom::Point best_transformation = transformation;
557 /* The current best metric for the best transformation; lower is better, NR_HUGE
558 ** means that we haven't snapped anything.
559 */
560 Geom::Point best_scale_metric(NR_HUGE, NR_HUGE);
561 Inkscape::SnappedPoint best_snapped_point;
562 g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point
563 g_assert(best_snapped_point.getAtIntersection() == false);
565 std::vector<std::pair<Geom::Point, int> >::const_iterator j = transformed_points.begin();
567 // std::cout << std::endl;
568 for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = points.begin(); i != points.end(); i++) {
570 /* Snap it */
571 Inkscape::SnappedPoint snapped_point;
572 Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint;
573 Geom::Point const b = ((*i).first - origin); // vector to original point
575 if (constrained) {
576 if ((transformation_type == SCALE || transformation_type == STRETCH) && uniform) {
577 // When uniformly scaling, each point will have its own unique constraint line,
578 // running from the scaling origin to the original untransformed point. We will
579 // calculate that line here
580 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, b);
581 } else if (transformation_type == STRETCH) { // when non-uniform stretching {
582 dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i).first, component_vectors[dim]);
583 } else if (transformation_type == TRANSLATION) {
584 // When doing a constrained translation, all points will move in the same direction, i.e.
585 // either horizontally or vertically. The lines along which they move are therefore all
586 // parallel, but might not be colinear. Therefore we will have to set the point through
587 // which the constraint-line runs here, for each point individually.
588 dedicated_constraint.setPoint((*i).first);
589 } // else: leave the original constraint, e.g. for skewing
590 if (transformation_type == SCALE && !uniform) {
591 g_warning("Non-uniform constrained scaling is not supported!");
592 }
593 snapped_point = constrainedSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), dedicated_constraint, i == points.begin(), bbox);
594 } else {
595 bool const c1 = fabs(b[Geom::X]) < 1e-6;
596 bool const c2 = fabs(b[Geom::Y]) < 1e-6;
597 if (transformation_type == SCALE && (c1 || c2) && !(c1 && c2)) {
598 // When scaling, a point aligned either horizontally or vertically with the origin can only
599 // move in that specific direction; therefore it should only snap in that direction, otherwise
600 // we will get snapped points with an invalid transformation
601 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, component_vectors[c1]);
602 snapped_point = constrainedSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), dedicated_constraint, i == points.begin(), bbox);
603 } else {
604 snapped_point = freeSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), i == points.begin(), bbox);
605 }
606 }
607 // std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl;
608 snapped_point.setPointerDistance(Geom::L2(pointer - (*i).first));
610 Geom::Point result;
611 Geom::Point scale_metric(NR_HUGE, NR_HUGE);
613 if (snapped_point.getSnapped()) {
614 /* We snapped. Find the transformation that describes where the snapped point has
615 ** ended up, and also the metric for this transformation.
616 */
617 Geom::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point
618 //Geom::Point const b = (*i - origin); // vector to original point
620 switch (transformation_type) {
621 case TRANSLATION:
622 result = snapped_point.getPoint() - (*i).first;
623 /* Consider the case in which a box is almost aligned with a grid in both
624 * horizontal and vertical directions. The distance to the intersection of
625 * the grid lines will always be larger then the distance to a single grid
626 * line. If we prefer snapping to an intersection instead of to a single
627 * grid line, then we cannot use "metric = Geom::L2(result)". Therefore the
628 * snapped distance will be used as a metric. Please note that the snapped
629 * distance is defined as the distance to the nearest line of the intersection,
630 * and not to the intersection itself!
631 */
632 // Only for translations, the relevant metric will be the real snapped distance,
633 // so we don't have to do anything special here
634 break;
635 case SCALE:
636 {
637 result = Geom::Point(NR_HUGE, NR_HUGE);
638 // If this point *i is horizontally or vertically aligned with
639 // the origin of the scaling, then it will scale purely in X or Y
640 // We can therefore only calculate the scaling in this direction
641 // and the scaling factor for the other direction should remain
642 // untouched (unless scaling is uniform ofcourse)
643 for (int index = 0; index < 2; index++) {
644 if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
645 if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
646 result[index] = a[index] / b[index]; // then calculate it!
647 }
648 // we might leave result[1-index] = NR_HUGE
649 // if scaling didn't occur in the other direction
650 }
651 }
652 // Compare the resulting scaling with the desired scaling
653 scale_metric = result - transformation; // One or both of its components might be NR_HUGE
654 break;
655 }
656 case STRETCH:
657 result = Geom::Point(NR_HUGE, NR_HUGE);
658 if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
659 result[dim] = a[dim] / b[dim];
660 result[1-dim] = uniform ? result[dim] : 1;
661 } else { // STRETCHING might occur for this point, but only when the stretching is uniform
662 if (uniform && fabs(b[1-dim]) > 1e-6) {
663 result[1-dim] = a[1-dim] / b[1-dim];
664 result[dim] = result[1-dim];
665 }
666 }
667 // Store the metric for this transformation as a virtual distance
668 snapped_point.setSnapDistance(std::abs(result[dim] - transformation[dim]));
669 snapped_point.setSecondSnapDistance(NR_HUGE);
670 break;
671 case SKEW:
672 result[0] = (snapped_point.getPoint()[dim] - ((*i).first)[dim]) / (((*i).first)[1 - dim] - origin[1 - dim]); // skew factor
673 result[1] = transformation[1]; // scale factor
674 // Store the metric for this transformation as a virtual distance
675 snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
676 snapped_point.setSecondSnapDistance(NR_HUGE);
677 break;
678 default:
679 g_assert_not_reached();
680 }
682 // When scaling, we're considering the best transformation in each direction separately. We will have a metric in each
683 // direction, whereas for all other transformation we only a single one-dimensional metric. That's why we need to handle
684 // the scaling metric differently
685 if (transformation_type == SCALE) {
686 for (int index = 0; index < 2; index++) {
687 if (fabs(scale_metric[index]) < fabs(best_scale_metric[index])) {
688 best_transformation[index] = result[index];
689 best_scale_metric[index] = fabs(scale_metric[index]);
690 // When scaling, we're considering the best transformation in each direction separately
691 // Therefore two different snapped points might together make a single best transformation
692 // We will however return only a single snapped point (e.g. to display the snapping indicator)
693 best_snapped_point = snapped_point;
694 // std::cout << "SEL ";
695 } // else { std::cout << " ";}
696 }
697 if (uniform) {
698 if (best_scale_metric[0] < best_scale_metric[1]) {
699 best_transformation[1] = best_transformation[0];
700 best_scale_metric[1] = best_scale_metric[0];
701 } else {
702 best_transformation[0] = best_transformation[1];
703 best_scale_metric[0] = best_scale_metric[1];
704 }
705 }
706 } else { // For all transformations other than scaling
707 if (best_snapped_point.isOtherSnapBetter(snapped_point, true)) {
708 best_transformation = result;
709 best_snapped_point = snapped_point;
710 }
711 }
712 }
714 j++;
715 }
717 Geom::Coord best_metric;
718 if (transformation_type == SCALE) {
719 // When scaling, don't ever exit with one of scaling components set to NR_HUGE
720 for (int index = 0; index < 2; index++) {
721 if (best_transformation[index] == NR_HUGE) {
722 if (uniform && best_transformation[1-index] < NR_HUGE) {
723 best_transformation[index] = best_transformation[1-index];
724 } else {
725 best_transformation[index] = transformation[index];
726 }
727 }
728 }
729 best_metric = std::min(best_scale_metric[0], best_scale_metric[1]);
730 } else { // For all transformations other than scaling
731 best_metric = best_snapped_point.getSnapDistance();
732 }
734 best_snapped_point.setTransformation(best_transformation);
735 // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
736 // These rounding errors might be caused by NRRects, see bug #1584301
737 best_snapped_point.setSnapDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
738 return best_snapped_point;
739 }
742 /**
743 * \brief Apply a translation to a set of points and try to snap freely in 2 degrees-of-freedom
744 *
745 * \param point_type Category of points to which the source point belongs: node or bounding box.
746 * \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.
747 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
748 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred
749 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
750 */
752 Inkscape::SnappedPoint SnapManager::freeSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
753 std::vector<std::pair<Geom::Point, int> > const &p,
754 Geom::Point const &pointer,
755 Geom::Point const &tr) const
756 {
757 if (p.size() == 1) {
758 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false), (p.at(0)).second));
759 }
761 return _snapTransformed(point_type, p, pointer, false, Geom::Point(0,0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
762 }
764 /**
765 * \brief Apply a translation to a set of points and try to snap along a constraint
766 *
767 * \param point_type Category of points to which the source point belongs: node or bounding box.
768 * \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.
769 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
770 * \param constraint The direction or line along which snapping must occur.
771 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred.
772 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
773 */
775 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
776 std::vector<std::pair<Geom::Point, int> > const &p,
777 Geom::Point const &pointer,
778 Inkscape::Snapper::ConstraintLine const &constraint,
779 Geom::Point const &tr) const
780 {
781 if (p.size() == 1) {
782 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false), (p.at(0)).second));
783 }
785 return _snapTransformed(point_type, p, pointer, true, constraint, TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
786 }
789 /**
790 * \brief Apply a scaling to a set of points and try to snap freely in 2 degrees-of-freedom
791 *
792 * \param point_type Category of points to which the source point belongs: node or bounding box.
793 * \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.
794 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
795 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
796 * \param o Origin of the scaling
797 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
798 */
800 Inkscape::SnappedPoint SnapManager::freeSnapScale(Inkscape::SnapPreferences::PointType point_type,
801 std::vector<std::pair<Geom::Point, int> > const &p,
802 Geom::Point const &pointer,
803 Geom::Scale const &s,
804 Geom::Point const &o) const
805 {
806 if (p.size() == 1) {
807 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false), (p.at(0)).second));
808 }
810 return _snapTransformed(point_type, p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
811 }
814 /**
815 * \brief Apply a scaling to a set of points and snap such that the aspect ratio of the selection is preserved
816 *
817 * \param point_type Category of points to which the source point belongs: node or bounding box.
818 * \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.
819 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
820 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
821 * \param o Origin of the scaling
822 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
823 */
825 Inkscape::SnappedPoint SnapManager::constrainedSnapScale(Inkscape::SnapPreferences::PointType point_type,
826 std::vector<std::pair<Geom::Point, int> > const &p,
827 Geom::Point const &pointer,
828 Geom::Scale const &s,
829 Geom::Point const &o) const
830 {
831 // When constrained scaling, only uniform scaling is supported.
832 if (p.size() == 1) {
833 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true), (p.at(0)).second));
834 }
836 return _snapTransformed(point_type, p, pointer, true, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
837 }
839 /**
840 * \brief Apply a stretch to a set of points and snap such that the direction of the stretch is preserved
841 *
842 * \param point_type Category of points to which the source point belongs: node or bounding box.
843 * \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.
844 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
845 * \param s Proposed stretch; the final stretch can only be calculated after snapping has occurred
846 * \param o Origin of the stretching
847 * \param d Dimension in which to apply proposed stretch.
848 * \param u true if the stretch should be uniform (i.e. to be applied equally in both dimensions)
849 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
850 */
852 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(Inkscape::SnapPreferences::PointType point_type,
853 std::vector<std::pair<Geom::Point, int> > const &p,
854 Geom::Point const &pointer,
855 Geom::Coord const &s,
856 Geom::Point const &o,
857 Geom::Dim2 d,
858 bool u) const
859 {
860 if (p.size() == 1) {
861 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), STRETCH, Geom::Point(s, s), o, d, u), (p.at(0)).second));
862 }
864 return _snapTransformed(point_type, p, pointer, true, Geom::Point(0,0), STRETCH, Geom::Point(s, s), o, d, u);
865 }
867 /**
868 * \brief Apply a skew to a set of points and snap such that the direction of the skew is preserved
869 *
870 * \param point_type Category of points to which the source point belongs: node or bounding box.
871 * \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.
872 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
873 * \param constraint The direction or line along which snapping must occur.
874 * \param s Proposed skew; the final skew can only be calculated after snapping has occurred
875 * \param o Origin of the proposed skew
876 * \param d Dimension in which to apply proposed skew.
877 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
878 */
880 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(Inkscape::SnapPreferences::PointType point_type,
881 std::vector<std::pair<Geom::Point, int> > const &p,
882 Geom::Point const &pointer,
883 Inkscape::Snapper::ConstraintLine 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 g_assert(!(point_type & Inkscape::SnapPreferences::SNAPPOINT_BBOX));
897 if (p.size() == 1) {
898 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), SKEW, s, o, d, false), (p.at(0)).second));
899 }
901 return _snapTransformed(point_type, p, pointer, true, constraint, SKEW, s, o, d, false);
902 }
904 /**
905 * \brief Given a set of possible snap targets, find the best target (which is not necessarily
906 * also the nearest target), and show the snap indicator if requested
907 *
908 * \param p Current position of the snap source
909 * \param source_type Detailed description of the source type, will be used by the snap indicator
910 * \param sc A structure holding all snap targets that have been found so far
911 * \param constrained True if the snap is constrained, e.g. for stretching or for purely horizontal translation.
912 * \param noCurves If true, then do consider snapping to intersections of curves, but not to the curves themself
913 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
914 */
916 Inkscape::SnappedPoint SnapManager::findBestSnap(Geom::Point const &p,
917 Inkscape::SnapSourceType const source_type,
918 SnappedConstraints &sc,
919 bool constrained,
920 bool noCurves) const
921 {
923 /*
924 std::cout << "Type and number of snapped constraints: " << std::endl;
925 std::cout << " Points : " << sc.points.size() << std::endl;
926 std::cout << " Lines : " << sc.lines.size() << std::endl;
927 std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
928 std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
929 std::cout << " Curves : " << sc.curves.size()<< std::endl;
930 */
932 // Store all snappoints
933 std::list<Inkscape::SnappedPoint> sp_list;
935 // search for the closest snapped point
936 Inkscape::SnappedPoint closestPoint;
937 if (getClosestSP(sc.points, closestPoint)) {
938 sp_list.push_back(closestPoint);
939 }
941 // search for the closest snapped curve
942 if (!noCurves) {
943 Inkscape::SnappedCurve closestCurve;
944 if (getClosestCurve(sc.curves, closestCurve)) {
945 sp_list.push_back(Inkscape::SnappedPoint(closestCurve));
946 }
947 }
949 if (snapprefs.getSnapIntersectionCS()) {
950 // search for the closest snapped intersection of curves
951 Inkscape::SnappedPoint closestCurvesIntersection;
952 if (getClosestIntersectionCS(sc.curves, p, closestCurvesIntersection, _desktop->dt2doc())) {
953 closestCurvesIntersection.setSource(source_type);
954 sp_list.push_back(closestCurvesIntersection);
955 }
956 }
958 // search for the closest snapped grid line
959 Inkscape::SnappedLine closestGridLine;
960 if (getClosestSL(sc.grid_lines, closestGridLine)) {
961 sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
962 }
964 // search for the closest snapped guide line
965 Inkscape::SnappedLine closestGuideLine;
966 if (getClosestSL(sc.guide_lines, closestGuideLine)) {
967 sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
968 }
970 // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
971 // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
973 // When doing a constrained snap however, we're already at an intersection of the constrained line and
974 // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
975 // no need to look for additional intersections
976 if (!constrained) {
977 // search for the closest snapped intersection of grid lines
978 Inkscape::SnappedPoint closestGridPoint;
979 if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
980 closestGridPoint.setSource(source_type);
981 closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
982 sp_list.push_back(closestGridPoint);
983 }
985 // search for the closest snapped intersection of guide lines
986 Inkscape::SnappedPoint closestGuidePoint;
987 if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
988 closestGuidePoint.setSource(source_type);
989 closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
990 sp_list.push_back(closestGuidePoint);
991 }
993 // search for the closest snapped intersection of grid with guide lines
994 if (snapprefs.getSnapIntersectionGG()) {
995 Inkscape::SnappedPoint closestGridGuidePoint;
996 if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
997 closestGridGuidePoint.setSource(source_type);
998 closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
999 sp_list.push_back(closestGridGuidePoint);
1000 }
1001 }
1002 }
1004 // now let's see which snapped point gets a thumbs up
1005 Inkscape::SnappedPoint bestSnappedPoint = Inkscape::SnappedPoint(p, Inkscape::SNAPSOURCE_UNDEFINED, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
1006 // std::cout << "Finding the best snap..." << std::endl;
1007 for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
1008 // first find out if this snapped point is within snapping range
1009 // std::cout << "sp = " << from_2geom((*i).getPoint());
1010 if ((*i).getSnapDistance() <= (*i).getTolerance()) {
1011 // if it's the first point, or if it is closer than the best snapped point so far
1012 if (i == sp_list.begin() || bestSnappedPoint.isOtherSnapBetter(*i, false)) {
1013 // then prefer this point over the previous one
1014 bestSnappedPoint = *i;
1015 }
1016 }
1017 // std::cout << std::endl;
1018 }
1020 // Update the snap indicator, if requested
1021 if (_snapindicator) {
1022 if (bestSnappedPoint.getSnapped()) {
1023 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
1024 } else {
1025 _desktop->snapindicator->remove_snaptarget();
1026 }
1027 }
1029 // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl;
1030 return bestSnappedPoint;
1031 }
1033 /**
1034 * \brief Prepare the snap manager for the actual snapping, which includes building a list of snap targets
1035 * to ignore and toggling the snap indicator
1036 *
1037 * There are two overloaded setup() methods, of which this one only allows for a single item to be ignored
1038 * whereas the other one will take a list of items to ignore
1039 *
1040 * \param desktop Reference to the desktop to which this snap manager is attached
1041 * \param snapindicator If true then a snap indicator will be displayed automatically (when enabled in the preferences)
1042 * \param item_to_ignore This item will not be snapped to, e.g. the item that is currently being dragged. This avoids "self-snapping"
1043 * \param unselected_nodes Stationary nodes of the path that is currently being edited in the node tool and
1044 * that can be snapped too. Nodes not in this list will not be snapped to, to avoid "self-snapping". Of each
1045 * unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored
1046 * \param guide_to_ignore Guide that is currently being dragged and should not be snapped to
1047 */
1049 void SnapManager::setup(SPDesktop const *desktop,
1050 bool snapindicator,
1051 SPItem const *item_to_ignore,
1052 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
1053 SPGuide *guide_to_ignore)
1054 {
1055 g_assert(desktop != NULL);
1056 _item_to_ignore = item_to_ignore;
1057 _items_to_ignore = NULL;
1058 _desktop = desktop;
1059 _snapindicator = snapindicator;
1060 _unselected_nodes = unselected_nodes;
1061 _guide_to_ignore = guide_to_ignore;
1062 }
1064 /**
1065 * \brief Prepare the snap manager for the actual snapping, which includes building a list of snap targets
1066 * to ignore and toggling the snap indicator
1067 *
1068 * There are two overloaded setup() methods, of which the other one only allows for a single item to be ignored
1069 * whereas this one will take a list of items to ignore
1070 *
1071 * \param desktop Reference to the desktop to which this snap manager is attached
1072 * \param snapindicator If true then a snap indicator will be displayed automatically (when enabled in the preferences)
1073 * \param items_to_ignore These items will not be snapped to, e.g. the items that are currently being dragged. This avoids "self-snapping"
1074 * \param unselected_nodes Stationary nodes of the path that is currently being edited in the node tool and
1075 * that can be snapped too. Nodes not in this list will not be snapped to, to avoid "self-snapping". Of each
1076 * unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored
1077 * \param guide_to_ignore Guide that is currently being dragged and should not be snapped to
1078 */
1080 void SnapManager::setup(SPDesktop const *desktop,
1081 bool snapindicator,
1082 std::vector<SPItem const *> &items_to_ignore,
1083 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
1084 SPGuide *guide_to_ignore)
1085 {
1086 g_assert(desktop != NULL);
1087 _item_to_ignore = NULL;
1088 _items_to_ignore = &items_to_ignore;
1089 _desktop = desktop;
1090 _snapindicator = snapindicator;
1091 _unselected_nodes = unselected_nodes;
1092 _guide_to_ignore = guide_to_ignore;
1093 }
1095 SPDocument *SnapManager::getDocument() const
1096 {
1097 return _named_view->document;
1098 }
1100 /**
1101 * \brief Takes an untransformed point, applies the given transformation, and returns the transformed point. Eliminates lots of duplicated code
1102 *
1103 * \param p The untransformed position of the point, paired with an identifier of the type of the snap source.
1104 * \param transformation_type Type of transformation to apply.
1105 * \param transformation Mathematical description of the transformation; details depend on the type.
1106 * \param origin Origin of the transformation, if applicable.
1107 * \param dim Dimension to which the transformation applies, if applicable.
1108 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
1109 * \return The position of the point after transformation
1110 */
1112 Geom::Point SnapManager::_transformPoint(std::pair<Geom::Point, int> const &p,
1113 Transformation const transformation_type,
1114 Geom::Point const &transformation,
1115 Geom::Point const &origin,
1116 Geom::Dim2 const dim,
1117 bool const uniform) const
1118 {
1119 /* Work out the transformed version of this point */
1120 Geom::Point transformed;
1121 switch (transformation_type) {
1122 case TRANSLATION:
1123 transformed = p.first + transformation;
1124 break;
1125 case SCALE:
1126 transformed = (p.first - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
1127 break;
1128 case STRETCH:
1129 {
1130 Geom::Scale s(1, 1);
1131 if (uniform)
1132 s[Geom::X] = s[Geom::Y] = transformation[dim];
1133 else {
1134 s[dim] = transformation[dim];
1135 s[1 - dim] = 1;
1136 }
1137 transformed = ((p.first - origin) * s) + origin;
1138 break;
1139 }
1140 case SKEW:
1141 // Apply the skew factor
1142 transformed[dim] = (p.first)[dim] + transformation[0] * ((p.first)[1 - dim] - origin[1 - dim]);
1143 // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
1144 // Apply that scale factor here
1145 transformed[1-dim] = (p.first - origin)[1 - dim] * transformation[1] + origin[1 - dim];
1146 break;
1147 default:
1148 g_assert_not_reached();
1149 }
1151 return transformed;
1152 }
1154 /**
1155 * \brief Mark the location of the snap source (not the snap target!) on the canvas by drawing a symbol
1156 *
1157 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
1158 * \param p The transformed position of the source point, paired with an identifier of the type of the snap source.
1159 */
1161 void SnapManager::_displaySnapsource(Inkscape::SnapPreferences::PointType point_type, std::pair<Geom::Point, int> const &p) const {
1163 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
1164 if (prefs->getBool("/options/snapclosestonly/value")) {
1165 bool p_is_a_node = point_type & Inkscape::SnapPreferences::SNAPPOINT_NODE;
1166 bool p_is_a_bbox = point_type & Inkscape::SnapPreferences::SNAPPOINT_BBOX;
1167 if (snapprefs.getSnapEnabledGlobally() && ((p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) {
1168 _desktop->snapindicator->set_new_snapsource(p);
1169 } else {
1170 _desktop->snapindicator->remove_snapsource();
1171 }
1172 }
1173 }
1175 /*
1176 Local Variables:
1177 mode:c++
1178 c-file-style:"stroustrup"
1179 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1180 indent-tabs-mode:nil
1181 fill-column:99
1182 End:
1183 */
1184 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :