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 }
382 // First project the mouse pointer onto the constraint
383 Geom::Point pp = constraint.projection(p);
384 // Then try to snap the projected point
386 SnappedConstraints sc;
387 SnapperList const snappers = getSnappers();
388 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
389 (*i)->constrainedSnap(sc, point_type, pp, source_type, first_point, bbox_to_snap, constraint, items_to_ignore);
390 }
392 if (_item_to_ignore) {
393 delete items_to_ignore;
394 }
396 return findBestSnap(pp, source_type, sc, true);
397 }
399 /**
400 * \brief Try to snap a point of a guide to another guide or to a node
401 *
402 * Try to snap a point of a guide to another guide or to a node in two degrees-
403 * of-freedom, i.e. snap in any direction on the two dimensional canvas to the
404 * nearest snap target. This method is used when dragging or rotating a guide
405 *
406 * PS: SnapManager::setup() must have been called before calling this method,
407 *
408 * \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
409 * \param guide_normal Vector normal to the guide line
410 */
411 void SnapManager::guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const
412 {
413 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
414 return;
415 }
417 if (!(object.GuidesMightSnap() || snapprefs.getSnapToGuides())) {
418 return;
419 }
421 Inkscape::SnapSourceType source_type = Inkscape::SNAPSOURCE_GUIDE_ORIGIN;
422 if (drag_type == SP_DRAG_ROTATE) {
423 source_type = Inkscape::SNAPSOURCE_GUIDE;
424 }
426 // Snap to nodes
427 SnappedConstraints sc;
428 if (object.GuidesMightSnap()) {
429 object.guideFreeSnap(sc, p, guide_normal);
430 }
432 // Snap to guides & grid lines
433 SnapperList snappers = getGridSnappers();
434 snappers.push_back(&guide);
435 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
436 (*i)->freeSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, source_type, true, Geom::OptRect(), NULL, NULL);
437 }
439 // Snap to intersections of curves, but not to the curves themselves! (see _snapTranslatingGuideToNodes in object-snapper.cpp)
440 Inkscape::SnappedPoint const s = findBestSnap(p, source_type, sc, false, true);
442 s.getPoint(p);
443 }
445 /**
446 * \brief Try to snap a point on a guide to the intersection with another guide or a path
447 *
448 * Try to snap a point on a guide to the intersection of that guide with another
449 * guide or with a path. The snapped point will lie somewhere on the guide-line,
450 * making this is a constrained snap, i.e. in only one degree-of-freedom.
451 * This method is used when dragging the origin of the guide along the guide itself.
452 *
453 * PS: SnapManager::setup() must have been called before calling this method,
454 *
455 * \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
456 * \param guide_normal Vector normal to the guide line
457 */
459 void SnapManager::guideConstrainedSnap(Geom::Point &p, SPGuide const &guideline) const
460 {
461 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
462 return;
463 }
465 if (!(object.ThisSnapperMightSnap() || snapprefs.getSnapToGuides())) {
466 return;
467 }
469 Inkscape::SnapSourceType source_type = Inkscape::SNAPSOURCE_GUIDE_ORIGIN;
471 // Snap to nodes or paths
472 SnappedConstraints sc;
473 Inkscape::Snapper::ConstraintLine cl(guideline.point_on_line, Geom::rot90(guideline.normal_to_line));
474 if (object.ThisSnapperMightSnap()) {
475 object.constrainedSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, source_type, true, Geom::OptRect(), cl, NULL);
476 }
478 // Snap to guides & grid lines
479 SnapperList snappers = getGridSnappers();
480 snappers.push_back(&guide);
481 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
482 (*i)->constrainedSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, source_type, true, Geom::OptRect(), cl, NULL);
483 }
485 Inkscape::SnappedPoint const s = findBestSnap(p, source_type, sc, false);
486 s.getPoint(p);
487 }
489 /**
490 * \brief Method for snapping sets of points while they are being transformed
491 *
492 * Method for snapping sets of points while they are being transformed, when using
493 * for example the selector tool. This method is for internal use only, and should
494 * not have to be called directly. Use freeSnapTransalation(), constrainedSnapScale(),
495 * etc. instead.
496 *
497 * This is what is being done in this method: transform each point, find out whether
498 * a free snap or constrained snap is more appropriate, do the snapping, calculate
499 * some metrics to quantify the snap "distance", and see if it's better than the
500 * previous snap. Finally, the best ("nearest") snap from all these points is returned.
501 *
502 * \param type Category of points to which the source point belongs: node or bounding box.
503 * \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.
504 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
505 * \param constrained true if the snap is constrained, e.g. for stretching or for purely horizontal translation.
506 * \param constraint The direction or line along which snapping must occur, if 'constrained' is true; otherwise undefined.
507 * \param transformation_type Type of transformation to apply to points before trying to snap them.
508 * \param transformation Description of the transformation; details depend on the type.
509 * \param origin Origin of the transformation, if applicable.
510 * \param dim Dimension to which the transformation applies, if applicable.
511 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
512 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
513 */
515 Inkscape::SnappedPoint SnapManager::_snapTransformed(
516 Inkscape::SnapPreferences::PointType type,
517 std::vector<std::pair<Geom::Point, int> > const &points,
518 Geom::Point const &pointer,
519 bool constrained,
520 Inkscape::Snapper::ConstraintLine const &constraint,
521 Transformation transformation_type,
522 Geom::Point const &transformation,
523 Geom::Point const &origin,
524 Geom::Dim2 dim,
525 bool uniform) const
526 {
527 /* We have a list of points, which we are proposing to transform in some way. We need to see
528 ** if any of these points, when transformed, snap to anything. If they do, we return the
529 ** appropriate transformation with `true'; otherwise we return the original scale with `false'.
530 */
532 /* Quick check to see if we have any snappers that are enabled
533 ** Also used to globally disable all snapping
534 */
535 if (someSnapperMightSnap() == false) {
536 return Inkscape::SnappedPoint();
537 }
539 std::vector<std::pair<Geom::Point, int> > transformed_points;
540 Geom::Rect bbox;
542 for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = points.begin(); i != points.end(); i++) {
544 /* Work out the transformed version of this point */
545 Geom::Point transformed = _transformPoint(*i, transformation_type, transformation, origin, dim, uniform);
547 // add the current transformed point to the box hulling all transformed points
548 if (i == points.begin()) {
549 bbox = Geom::Rect(transformed, transformed);
550 } else {
551 bbox.expandTo(transformed);
552 }
554 transformed_points.push_back(std::make_pair(transformed, (*i).second));
555 }
557 /* The current best transformation */
558 Geom::Point best_transformation = transformation;
560 /* The current best metric for the best transformation; lower is better, NR_HUGE
561 ** means that we haven't snapped anything.
562 */
563 Geom::Point best_scale_metric(NR_HUGE, NR_HUGE);
564 Inkscape::SnappedPoint best_snapped_point;
565 g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point
566 g_assert(best_snapped_point.getAtIntersection() == false);
568 std::vector<std::pair<Geom::Point, int> >::const_iterator j = transformed_points.begin();
570 // std::cout << std::endl;
571 for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = points.begin(); i != points.end(); i++) {
573 /* Snap it */
574 Inkscape::SnappedPoint snapped_point;
575 Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint;
576 Geom::Point const b = ((*i).first - origin); // vector to original point
578 if (constrained) {
579 if ((transformation_type == SCALE || transformation_type == STRETCH) && uniform) {
580 // When uniformly scaling, each point will have its own unique constraint line,
581 // running from the scaling origin to the original untransformed point. We will
582 // calculate that line here
583 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, b);
584 } else if (transformation_type == STRETCH) { // when non-uniform stretching {
585 dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i).first, component_vectors[dim]);
586 } else if (transformation_type == TRANSLATION) {
587 // When doing a constrained translation, all points will move in the same direction, i.e.
588 // either horizontally or vertically. The lines along which they move are therefore all
589 // parallel, but might not be colinear. Therefore we will have to set the point through
590 // which the constraint-line runs here, for each point individually.
591 dedicated_constraint.setPoint((*i).first);
592 } // else: leave the original constraint, e.g. for skewing
593 if (transformation_type == SCALE && !uniform) {
594 g_warning("Non-uniform constrained scaling is not supported!");
595 }
596 snapped_point = constrainedSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), dedicated_constraint, i == points.begin(), bbox);
597 } else {
598 bool const c1 = fabs(b[Geom::X]) < 1e-6;
599 bool const c2 = fabs(b[Geom::Y]) < 1e-6;
600 if (transformation_type == SCALE && (c1 || c2) && !(c1 && c2)) {
601 // When scaling, a point aligned either horizontally or vertically with the origin can only
602 // move in that specific direction; therefore it should only snap in that direction, otherwise
603 // we will get snapped points with an invalid transformation
604 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, component_vectors[c1]);
605 snapped_point = constrainedSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), dedicated_constraint, i == points.begin(), bbox);
606 } else {
607 snapped_point = freeSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), i == points.begin(), bbox);
608 }
609 }
610 // std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl;
611 snapped_point.setPointerDistance(Geom::L2(pointer - (*i).first));
613 Geom::Point result;
614 Geom::Point scale_metric(NR_HUGE, NR_HUGE);
616 if (snapped_point.getSnapped()) {
617 /* We snapped. Find the transformation that describes where the snapped point has
618 ** ended up, and also the metric for this transformation.
619 */
620 Geom::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point
621 //Geom::Point const b = (*i - origin); // vector to original point
623 switch (transformation_type) {
624 case TRANSLATION:
625 result = snapped_point.getPoint() - (*i).first;
626 /* Consider the case in which a box is almost aligned with a grid in both
627 * horizontal and vertical directions. The distance to the intersection of
628 * the grid lines will always be larger then the distance to a single grid
629 * line. If we prefer snapping to an intersection instead of to a single
630 * grid line, then we cannot use "metric = Geom::L2(result)". Therefore the
631 * snapped distance will be used as a metric. Please note that the snapped
632 * distance is defined as the distance to the nearest line of the intersection,
633 * and not to the intersection itself!
634 */
635 // Only for translations, the relevant metric will be the real snapped distance,
636 // so we don't have to do anything special here
637 break;
638 case SCALE:
639 {
640 result = Geom::Point(NR_HUGE, NR_HUGE);
641 // If this point *i is horizontally or vertically aligned with
642 // the origin of the scaling, then it will scale purely in X or Y
643 // We can therefore only calculate the scaling in this direction
644 // and the scaling factor for the other direction should remain
645 // untouched (unless scaling is uniform ofcourse)
646 for (int index = 0; index < 2; index++) {
647 if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
648 if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
649 result[index] = a[index] / b[index]; // then calculate it!
650 }
651 // we might leave result[1-index] = NR_HUGE
652 // if scaling didn't occur in the other direction
653 }
654 }
655 // Compare the resulting scaling with the desired scaling
656 scale_metric = result - transformation; // One or both of its components might be NR_HUGE
657 break;
658 }
659 case STRETCH:
660 result = Geom::Point(NR_HUGE, NR_HUGE);
661 if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
662 result[dim] = a[dim] / b[dim];
663 result[1-dim] = uniform ? result[dim] : 1;
664 } else { // STRETCHING might occur for this point, but only when the stretching is uniform
665 if (uniform && fabs(b[1-dim]) > 1e-6) {
666 result[1-dim] = a[1-dim] / b[1-dim];
667 result[dim] = result[1-dim];
668 }
669 }
670 // Store the metric for this transformation as a virtual distance
671 snapped_point.setSnapDistance(std::abs(result[dim] - transformation[dim]));
672 snapped_point.setSecondSnapDistance(NR_HUGE);
673 break;
674 case SKEW:
675 result[0] = (snapped_point.getPoint()[dim] - ((*i).first)[dim]) / (((*i).first)[1 - dim] - origin[1 - dim]); // skew factor
676 result[1] = transformation[1]; // scale factor
677 // Store the metric for this transformation as a virtual distance
678 snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
679 snapped_point.setSecondSnapDistance(NR_HUGE);
680 break;
681 default:
682 g_assert_not_reached();
683 }
685 // When scaling, we're considering the best transformation in each direction separately. We will have a metric in each
686 // direction, whereas for all other transformation we only a single one-dimensional metric. That's why we need to handle
687 // the scaling metric differently
688 if (transformation_type == SCALE) {
689 for (int index = 0; index < 2; index++) {
690 if (fabs(scale_metric[index]) < fabs(best_scale_metric[index])) {
691 best_transformation[index] = result[index];
692 best_scale_metric[index] = fabs(scale_metric[index]);
693 // When scaling, we're considering the best transformation in each direction separately
694 // Therefore two different snapped points might together make a single best transformation
695 // We will however return only a single snapped point (e.g. to display the snapping indicator)
696 best_snapped_point = snapped_point;
697 // std::cout << "SEL ";
698 } // else { std::cout << " ";}
699 }
700 if (uniform) {
701 if (best_scale_metric[0] < best_scale_metric[1]) {
702 best_transformation[1] = best_transformation[0];
703 best_scale_metric[1] = best_scale_metric[0];
704 } else {
705 best_transformation[0] = best_transformation[1];
706 best_scale_metric[0] = best_scale_metric[1];
707 }
708 }
709 } else { // For all transformations other than scaling
710 if (best_snapped_point.isOtherSnapBetter(snapped_point, true)) {
711 best_transformation = result;
712 best_snapped_point = snapped_point;
713 }
714 }
715 }
717 j++;
718 }
720 Geom::Coord best_metric;
721 if (transformation_type == SCALE) {
722 // When scaling, don't ever exit with one of scaling components set to NR_HUGE
723 for (int index = 0; index < 2; index++) {
724 if (best_transformation[index] == NR_HUGE) {
725 if (uniform && best_transformation[1-index] < NR_HUGE) {
726 best_transformation[index] = best_transformation[1-index];
727 } else {
728 best_transformation[index] = transformation[index];
729 }
730 }
731 }
732 best_metric = std::min(best_scale_metric[0], best_scale_metric[1]);
733 } else { // For all transformations other than scaling
734 best_metric = best_snapped_point.getSnapDistance();
735 }
737 best_snapped_point.setTransformation(best_transformation);
738 // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
739 // These rounding errors might be caused by NRRects, see bug #1584301
740 best_snapped_point.setSnapDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
741 return best_snapped_point;
742 }
745 /**
746 * \brief Apply a translation to a set of points and try to snap freely in 2 degrees-of-freedom
747 *
748 * \param point_type Category of points to which the source point belongs: node or bounding box.
749 * \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.
750 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
751 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred
752 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
753 */
755 Inkscape::SnappedPoint SnapManager::freeSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
756 std::vector<std::pair<Geom::Point, int> > const &p,
757 Geom::Point const &pointer,
758 Geom::Point const &tr) const
759 {
760 if (p.size() == 1) {
761 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false), (p.at(0)).second));
762 }
764 return _snapTransformed(point_type, p, pointer, false, Geom::Point(0,0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
765 }
767 /**
768 * \brief Apply a translation to a set of points and try to snap along a constraint
769 *
770 * \param point_type Category of points to which the source point belongs: node or bounding box.
771 * \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.
772 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
773 * \param constraint The direction or line along which snapping must occur.
774 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred.
775 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
776 */
778 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
779 std::vector<std::pair<Geom::Point, int> > const &p,
780 Geom::Point const &pointer,
781 Inkscape::Snapper::ConstraintLine const &constraint,
782 Geom::Point const &tr) const
783 {
784 if (p.size() == 1) {
785 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false), (p.at(0)).second));
786 }
788 return _snapTransformed(point_type, p, pointer, true, constraint, TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
789 }
792 /**
793 * \brief Apply a scaling to a set of points and try to snap freely in 2 degrees-of-freedom
794 *
795 * \param point_type Category of points to which the source point belongs: node or bounding box.
796 * \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.
797 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
798 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
799 * \param o Origin of the scaling
800 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
801 */
803 Inkscape::SnappedPoint SnapManager::freeSnapScale(Inkscape::SnapPreferences::PointType point_type,
804 std::vector<std::pair<Geom::Point, int> > 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 _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));
811 }
813 return _snapTransformed(point_type, p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
814 }
817 /**
818 * \brief Apply a scaling to a set of points and snap such that the aspect ratio of the selection is preserved
819 *
820 * \param point_type Category of points to which the source point belongs: node or bounding box.
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(Inkscape::SnapPreferences::PointType point_type,
829 std::vector<std::pair<Geom::Point, int> > const &p,
830 Geom::Point const &pointer,
831 Geom::Scale const &s,
832 Geom::Point const &o) const
833 {
834 // When constrained scaling, only uniform scaling is supported.
835 if (p.size() == 1) {
836 _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));
837 }
839 return _snapTransformed(point_type, 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 point_type Category of points to which the source point belongs: node or bounding box.
846 * \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.
847 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
848 * \param s Proposed stretch; the final stretch can only be calculated after snapping has occurred
849 * \param o Origin of the stretching
850 * \param d Dimension in which to apply proposed stretch.
851 * \param u true if the stretch should be uniform (i.e. to be applied equally in both dimensions)
852 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
853 */
855 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(Inkscape::SnapPreferences::PointType point_type,
856 std::vector<std::pair<Geom::Point, int> > const &p,
857 Geom::Point const &pointer,
858 Geom::Coord const &s,
859 Geom::Point const &o,
860 Geom::Dim2 d,
861 bool u) const
862 {
863 if (p.size() == 1) {
864 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), STRETCH, Geom::Point(s, s), o, d, u), (p.at(0)).second));
865 }
867 return _snapTransformed(point_type, p, pointer, true, Geom::Point(0,0), STRETCH, Geom::Point(s, s), o, d, u);
868 }
870 /**
871 * \brief Apply a skew to a set of points and snap such that the direction of the skew is preserved
872 *
873 * \param point_type Category of points to which the source point belongs: node or bounding box.
874 * \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.
875 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
876 * \param constraint The direction or line along which snapping must occur.
877 * \param s Proposed skew; the final skew can only be calculated after snapping has occurred
878 * \param o Origin of the proposed skew
879 * \param d Dimension in which to apply proposed skew.
880 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
881 */
883 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(Inkscape::SnapPreferences::PointType point_type,
884 std::vector<std::pair<Geom::Point, int> > const &p,
885 Geom::Point const &pointer,
886 Inkscape::Snapper::ConstraintLine const &constraint,
887 Geom::Point const &s,
888 Geom::Point const &o,
889 Geom::Dim2 d) const
890 {
891 // "s" contains skew factor in s[0], and scale factor in s[1]
893 // Snapping the nodes of the bounding box of a selection that is being transformed, will only work if
894 // the transformation of the bounding box is equal to the transformation of the individual nodes. This is
895 // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
896 // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
897 // of bounding boxes is not allowed here.
898 g_assert(!(point_type & Inkscape::SnapPreferences::SNAPPOINT_BBOX));
900 if (p.size() == 1) {
901 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), SKEW, s, o, d, false), (p.at(0)).second));
902 }
904 return _snapTransformed(point_type, p, pointer, true, constraint, SKEW, s, o, d, false);
905 }
907 /**
908 * \brief Given a set of possible snap targets, find the best target (which is not necessarily
909 * also the nearest target), and show the snap indicator if requested
910 *
911 * \param p Current position of the snap source
912 * \param source_type Detailed description of the source type, will be used by the snap indicator
913 * \param sc A structure holding all snap targets that have been found so far
914 * \param constrained True if the snap is constrained, e.g. for stretching or for purely horizontal translation.
915 * \param noCurves If true, then do consider snapping to intersections of curves, but not to the curves themself
916 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
917 */
919 Inkscape::SnappedPoint SnapManager::findBestSnap(Geom::Point const &p,
920 Inkscape::SnapSourceType const source_type,
921 SnappedConstraints &sc,
922 bool constrained,
923 bool noCurves) const
924 {
926 /*
927 std::cout << "Type and number of snapped constraints: " << std::endl;
928 std::cout << " Points : " << sc.points.size() << std::endl;
929 std::cout << " Lines : " << sc.lines.size() << std::endl;
930 std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
931 std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
932 std::cout << " Curves : " << sc.curves.size()<< std::endl;
933 */
935 // Store all snappoints
936 std::list<Inkscape::SnappedPoint> sp_list;
938 // search for the closest snapped point
939 Inkscape::SnappedPoint closestPoint;
940 if (getClosestSP(sc.points, closestPoint)) {
941 sp_list.push_back(closestPoint);
942 }
944 // search for the closest snapped curve
945 if (!noCurves) {
946 Inkscape::SnappedCurve closestCurve;
947 if (getClosestCurve(sc.curves, closestCurve)) {
948 sp_list.push_back(Inkscape::SnappedPoint(closestCurve));
949 }
950 }
952 if (snapprefs.getSnapIntersectionCS()) {
953 // search for the closest snapped intersection of curves
954 Inkscape::SnappedPoint closestCurvesIntersection;
955 if (getClosestIntersectionCS(sc.curves, p, closestCurvesIntersection, _desktop->dt2doc())) {
956 closestCurvesIntersection.setSource(source_type);
957 sp_list.push_back(closestCurvesIntersection);
958 }
959 }
961 // search for the closest snapped grid line
962 Inkscape::SnappedLine closestGridLine;
963 if (getClosestSL(sc.grid_lines, closestGridLine)) {
964 sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
965 }
967 // search for the closest snapped guide line
968 Inkscape::SnappedLine closestGuideLine;
969 if (getClosestSL(sc.guide_lines, closestGuideLine)) {
970 sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
971 }
973 // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
974 // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
976 // When doing a constrained snap however, we're already at an intersection of the constrained line and
977 // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
978 // no need to look for additional intersections
979 if (!constrained) {
980 // search for the closest snapped intersection of grid lines
981 Inkscape::SnappedPoint closestGridPoint;
982 if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
983 closestGridPoint.setSource(source_type);
984 closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
985 sp_list.push_back(closestGridPoint);
986 }
988 // search for the closest snapped intersection of guide lines
989 Inkscape::SnappedPoint closestGuidePoint;
990 if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
991 closestGuidePoint.setSource(source_type);
992 closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
993 sp_list.push_back(closestGuidePoint);
994 }
996 // search for the closest snapped intersection of grid with guide lines
997 if (snapprefs.getSnapIntersectionGG()) {
998 Inkscape::SnappedPoint closestGridGuidePoint;
999 if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
1000 closestGridGuidePoint.setSource(source_type);
1001 closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
1002 sp_list.push_back(closestGridGuidePoint);
1003 }
1004 }
1005 }
1007 // now let's see which snapped point gets a thumbs up
1008 Inkscape::SnappedPoint bestSnappedPoint = Inkscape::SnappedPoint(p, Inkscape::SNAPSOURCE_UNDEFINED, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
1009 // std::cout << "Finding the best snap..." << std::endl;
1010 for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
1011 // first find out if this snapped point is within snapping range
1012 // std::cout << "sp = " << from_2geom((*i).getPoint());
1013 if ((*i).getSnapDistance() <= (*i).getTolerance()) {
1014 // if it's the first point, or if it is closer than the best snapped point so far
1015 if (i == sp_list.begin() || bestSnappedPoint.isOtherSnapBetter(*i, false)) {
1016 // then prefer this point over the previous one
1017 bestSnappedPoint = *i;
1018 }
1019 }
1020 // std::cout << std::endl;
1021 }
1023 // Update the snap indicator, if requested
1024 if (_snapindicator) {
1025 if (bestSnappedPoint.getSnapped()) {
1026 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
1027 } else {
1028 _desktop->snapindicator->remove_snaptarget();
1029 }
1030 }
1032 // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl;
1033 return bestSnappedPoint;
1034 }
1036 /**
1037 * \brief Prepare the snap manager for the actual snapping, which includes building a list of snap targets
1038 * to ignore and toggling the snap indicator
1039 *
1040 * There are two overloaded setup() methods, of which this one only allows for a single item to be ignored
1041 * whereas the other one will take a list of items to ignore
1042 *
1043 * \param desktop Reference to the desktop to which this snap manager is attached
1044 * \param snapindicator If true then a snap indicator will be displayed automatically (when enabled in the preferences)
1045 * \param item_to_ignore This item will not be snapped to, e.g. the item that is currently being dragged. This avoids "self-snapping"
1046 * \param unselected_nodes Stationary nodes of the path that is currently being edited in the node tool and
1047 * that can be snapped too. Nodes not in this list will not be snapped to, to avoid "self-snapping". Of each
1048 * unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored
1049 * \param guide_to_ignore Guide that is currently being dragged and should not be snapped to
1050 */
1052 void SnapManager::setup(SPDesktop const *desktop,
1053 bool snapindicator,
1054 SPItem const *item_to_ignore,
1055 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
1056 SPGuide *guide_to_ignore)
1057 {
1058 g_assert(desktop != NULL);
1059 _item_to_ignore = item_to_ignore;
1060 _items_to_ignore = NULL;
1061 _desktop = desktop;
1062 _snapindicator = snapindicator;
1063 _unselected_nodes = unselected_nodes;
1064 _guide_to_ignore = guide_to_ignore;
1065 }
1067 /**
1068 * \brief Prepare the snap manager for the actual snapping, which includes building a list of snap targets
1069 * to ignore and toggling the snap indicator
1070 *
1071 * There are two overloaded setup() methods, of which the other one only allows for a single item to be ignored
1072 * whereas this one will take a list of items to ignore
1073 *
1074 * \param desktop Reference to the desktop to which this snap manager is attached
1075 * \param snapindicator If true then a snap indicator will be displayed automatically (when enabled in the preferences)
1076 * \param items_to_ignore These items will not be snapped to, e.g. the items that are currently being dragged. This avoids "self-snapping"
1077 * \param unselected_nodes Stationary nodes of the path that is currently being edited in the node tool and
1078 * that can be snapped too. Nodes not in this list will not be snapped to, to avoid "self-snapping". Of each
1079 * unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored
1080 * \param guide_to_ignore Guide that is currently being dragged and should not be snapped to
1081 */
1083 void SnapManager::setup(SPDesktop const *desktop,
1084 bool snapindicator,
1085 std::vector<SPItem const *> &items_to_ignore,
1086 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
1087 SPGuide *guide_to_ignore)
1088 {
1089 g_assert(desktop != NULL);
1090 _item_to_ignore = NULL;
1091 _items_to_ignore = &items_to_ignore;
1092 _desktop = desktop;
1093 _snapindicator = snapindicator;
1094 _unselected_nodes = unselected_nodes;
1095 _guide_to_ignore = guide_to_ignore;
1096 }
1098 SPDocument *SnapManager::getDocument() const
1099 {
1100 return _named_view->document;
1101 }
1103 /**
1104 * \brief Takes an untransformed point, applies the given transformation, and returns the transformed point. Eliminates lots of duplicated code
1105 *
1106 * \param p The untransformed position of the point, paired with an identifier of the type of the snap source.
1107 * \param transformation_type Type of transformation to apply.
1108 * \param transformation Mathematical description of the transformation; details depend on the type.
1109 * \param origin Origin of the transformation, if applicable.
1110 * \param dim Dimension to which the transformation applies, if applicable.
1111 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
1112 * \return The position of the point after transformation
1113 */
1115 Geom::Point SnapManager::_transformPoint(std::pair<Geom::Point, int> const &p,
1116 Transformation const transformation_type,
1117 Geom::Point const &transformation,
1118 Geom::Point const &origin,
1119 Geom::Dim2 const dim,
1120 bool const uniform) const
1121 {
1122 /* Work out the transformed version of this point */
1123 Geom::Point transformed;
1124 switch (transformation_type) {
1125 case TRANSLATION:
1126 transformed = p.first + transformation;
1127 break;
1128 case SCALE:
1129 transformed = (p.first - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
1130 break;
1131 case STRETCH:
1132 {
1133 Geom::Scale s(1, 1);
1134 if (uniform)
1135 s[Geom::X] = s[Geom::Y] = transformation[dim];
1136 else {
1137 s[dim] = transformation[dim];
1138 s[1 - dim] = 1;
1139 }
1140 transformed = ((p.first - origin) * s) + origin;
1141 break;
1142 }
1143 case SKEW:
1144 // Apply the skew factor
1145 transformed[dim] = (p.first)[dim] + transformation[0] * ((p.first)[1 - dim] - origin[1 - dim]);
1146 // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
1147 // Apply that scale factor here
1148 transformed[1-dim] = (p.first - origin)[1 - dim] * transformation[1] + origin[1 - dim];
1149 break;
1150 default:
1151 g_assert_not_reached();
1152 }
1154 return transformed;
1155 }
1157 /**
1158 * \brief Mark the location of the snap source (not the snap target!) on the canvas by drawing a symbol
1159 *
1160 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
1161 * \param p The transformed position of the source point, paired with an identifier of the type of the snap source.
1162 */
1164 void SnapManager::_displaySnapsource(Inkscape::SnapPreferences::PointType point_type, std::pair<Geom::Point, int> const &p) const {
1166 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
1167 if (prefs->getBool("/options/snapclosestonly/value")) {
1168 bool p_is_a_node = point_type & Inkscape::SnapPreferences::SNAPPOINT_NODE;
1169 bool p_is_a_bbox = point_type & Inkscape::SnapPreferences::SNAPPOINT_BBOX;
1170 if (snapprefs.getSnapEnabledGlobally() && ((p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) {
1171 _desktop->snapindicator->set_new_snapsource(p);
1172 } else {
1173 _desktop->snapindicator->remove_snapsource();
1174 }
1175 }
1176 }
1178 /*
1179 Local Variables:
1180 mode:c++
1181 c-file-style:"stroustrup"
1182 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1183 indent-tabs-mode:nil
1184 fill-column:99
1185 End:
1186 */
1187 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :