1 #define __SP_DESKTOP_SNAP_C__
3 /**
4 * \file snap.cpp
5 * \brief SnapManager class.
6 *
7 * Authors:
8 * Lauris Kaplinski <lauris@kaplinski.com>
9 * Frank Felfe <innerspace@iname.com>
10 * Nathan Hurst <njh@njhurst.com>
11 * Carl Hetherington <inkscape@carlh.net>
12 * Diederik van Lierop <mail@diedenrezi.nl>
13 *
14 * Copyright (C) 2006-2007 Johan Engelen <johan@shouraizou.nl>
15 * Copyrigth (C) 2004 Nathan Hurst
16 * Copyright (C) 1999-2010 Authors
17 *
18 * Released under GNU GPL, read the file 'COPYING' for more information
19 */
21 #include <utility>
23 #include "sp-namedview.h"
24 #include "snap.h"
25 #include "snapped-line.h"
26 #include "snapped-curve.h"
28 #include "display/canvas-grid.h"
29 #include "display/snap-indicator.h"
31 #include "inkscape.h"
32 #include "desktop.h"
33 #include "selection.h"
34 #include "sp-guide.h"
35 #include "preferences.h"
36 #include "event-context.h"
37 using std::vector;
39 /**
40 * Construct a SnapManager for a SPNamedView.
41 *
42 * \param v `Owning' SPNamedView.
43 */
45 SnapManager::SnapManager(SPNamedView const *v) :
46 guide(this, 0),
47 object(this, 0),
48 snapprefs(),
49 _named_view(v)
50 {
51 }
53 /**
54 * \brief Return a list of snappers
55 *
56 * Inkscape snaps to objects, grids, and guides. For each of these snap targets a
57 * separate class is used, which has been derived from the base Snapper class. The
58 * getSnappers() method returns a list of pointers to instances of this class. This
59 * list contains exactly one instance of the guide snapper and of the object snapper
60 * class, but any number of grid snappers (because each grid has its own snapper
61 * instance)
62 *
63 * \return List of snappers that we use.
64 */
65 SnapManager::SnapperList
66 SnapManager::getSnappers() const
67 {
68 SnapManager::SnapperList s;
69 s.push_back(&guide);
70 s.push_back(&object);
72 SnapManager::SnapperList gs = getGridSnappers();
73 s.splice(s.begin(), gs);
75 return s;
76 }
78 /**
79 * \brief Return a list of gridsnappers
80 *
81 * Each grid has its own instance of the snapper class. This way snapping can
82 * be enabled per grid individually. A list will be returned containing the
83 * pointers to these instances, but only for grids that are being displayed
84 * and for which snapping is enabled.
85 *
86 * \return List of gridsnappers that we use.
87 */
88 SnapManager::SnapperList
89 SnapManager::getGridSnappers() const
90 {
91 SnapperList s;
93 if (_desktop && _desktop->gridsEnabled() && snapprefs.getSnapToGrids()) {
94 for ( GSList const *l = _named_view->grids; l != NULL; l = l->next) {
95 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
96 s.push_back(grid->snapper);
97 }
98 }
100 return s;
101 }
103 /**
104 * \brief Return true if any snapping might occur, whether its to grids, guides or objects
105 *
106 * Each snapper instance handles its own snapping target, e.g. grids, guides or
107 * objects. This method iterates through all these snapper instances and returns
108 * true if any of the snappers might possible snap, considering only the relevant
109 * snapping preferences.
110 *
111 * \return true if one of the snappers will try to snap to something.
112 */
114 bool SnapManager::someSnapperMightSnap() const
115 {
116 if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) {
117 return false;
118 }
120 SnapperList const s = getSnappers();
121 SnapperList::const_iterator i = s.begin();
122 while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
123 i++;
124 }
126 return (i != s.end());
127 }
129 /**
130 * \return true if one of the grids might be snapped to.
131 */
133 bool SnapManager::gridSnapperMightSnap() const
134 {
135 if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) {
136 return false;
137 }
139 SnapperList const s = getGridSnappers();
140 SnapperList::const_iterator i = s.begin();
141 while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
142 i++;
143 }
145 return (i != s.end());
146 }
148 /**
149 * \brief Try to snap a point to grids, guides or objects.
150 *
151 * Try to snap a point to grids, guides or objects, in two degrees-of-freedom,
152 * i.e. snap in any direction on the two dimensional canvas to the nearest
153 * snap target. freeSnapReturnByRef() is equal in snapping behavior to
154 * freeSnap(), but the former returns the snapped point trough the referenced
155 * parameter p. This parameter p initially contains the position of the snap
156 * source and will we overwritten by the target position if snapping has occurred.
157 * This makes snapping transparent to the calling code. If this is not desired
158 * because either the calling code must know whether snapping has occurred, or
159 * because the original position should not be touched, then freeSnap() should be
160 * called instead.
161 *
162 * PS:
163 * 1) SnapManager::setup() must have been called before calling this method,
164 * but only once for a set of points
165 * 2) Only to be used when a single source point is to be snapped; it assumes
166 * that source_num = 0, which is inefficient when snapping sets our source points
167 *
168 * \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred
169 * \param source_type Detailed description of the source type, will be used by the snap indicator
170 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
171 */
173 void SnapManager::freeSnapReturnByRef(Geom::Point &p,
174 Inkscape::SnapSourceType const source_type,
175 Geom::OptRect const &bbox_to_snap) const
176 {
177 //TODO: SnapCandidatePoint and point_type are somewhat redundant; can't we get rid of the point_type parameter?
178 Inkscape::SnappedPoint const s = freeSnap(Inkscape::SnapCandidatePoint(p, source_type), bbox_to_snap);
179 s.getPoint(p);
180 }
183 /**
184 * \brief Try to snap a point to grids, guides or objects.
185 *
186 * Try to snap a point to grids, guides or objects, in two degrees-of-freedom,
187 * i.e. snap in any direction on the two dimensional canvas to the nearest
188 * snap target. freeSnap() is equal in snapping behavior to
189 * freeSnapReturnByRef(). Please read the comments of the latter for more details
190 *
191 * PS: SnapManager::setup() must have been called before calling this method,
192 * but only once for a set of points
193 *
194 * \param p Source point to be snapped
195 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
196 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
197 */
200 Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::SnapCandidatePoint const &p,
201 Geom::OptRect const &bbox_to_snap) const
202 {
203 if (!someSnapperMightSnap()) {
204 return Inkscape::SnappedPoint(p, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false, false);
205 }
207 SnappedConstraints sc;
208 SnapperList const snappers = getSnappers();
210 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
211 (*i)->freeSnap(sc, p, bbox_to_snap, &_items_to_ignore, _unselected_nodes);
212 }
214 return findBestSnap(p, sc, false);
215 }
217 void SnapManager::preSnap(Inkscape::SnapCandidatePoint const &p)
218 {
219 // setup() must have been called before calling this method!
221 if (_snapindicator) {
222 _snapindicator = false; // prevent other methods from drawing a snap indicator; we want to control this here
223 Inkscape::SnappedPoint s = freeSnap(p);
224 if (s.getSnapped()) {
225 _desktop->snapindicator->set_new_snaptarget(s, true);
226 } else {
227 _desktop->snapindicator->remove_snaptarget(true);
228 }
229 _snapindicator = true; // restore the original value
230 }
231 }
233 /**
234 * \brief Snap to the closest multiple of a grid pitch
235 *
236 * When pasting, we would like to snap to the grid. Problem is that we don't know which
237 * nodes were aligned to the grid at the time of copying, so we don't know which nodes
238 * to snap. If we'd snap an unaligned node to the grid, previously aligned nodes would
239 * become unaligned. That's undesirable. Instead we will make sure that the offset
240 * between the source and its pasted copy is a multiple of the grid pitch. If the source
241 * was aligned, then the copy will therefore also be aligned.
242 *
243 * PS: Whether we really find a multiple also depends on the snapping range! Most users
244 * will have "always snap" enabled though, in which case a multiple will always be found.
245 * PS2: When multiple grids are present then the result will become ambiguous. There is no
246 * way to control to which grid this method will snap.
247 *
248 * \param t Vector that represents the offset of the pasted copy with respect to the original
249 * \return Offset vector after snapping to the closest multiple of a grid pitch
250 */
252 Geom::Point SnapManager::multipleOfGridPitch(Geom::Point const &t, Geom::Point const &origin)
253 {
254 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally())
255 return t;
257 if (_desktop && _desktop->gridsEnabled()) {
258 bool success = false;
259 Geom::Point nearest_multiple;
260 Geom::Coord nearest_distance = NR_HUGE;
261 Inkscape::SnappedPoint bestSnappedPoint(t);
263 // It will snap to the grid for which we find the closest snap. This might be a different
264 // grid than to which the objects were initially aligned. I don't see an easy way to fix
265 // this, so when using multiple grids one can get unexpected results
267 // Cannot use getGridSnappers() because we need both the grids AND their snappers
268 // Therefore we iterate through all grids manually
269 for (GSList const *l = _named_view->grids; l != NULL; l = l->next) {
270 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
271 const Inkscape::Snapper* snapper = grid->snapper;
272 if (snapper && snapper->ThisSnapperMightSnap()) {
273 // To find the nearest multiple of the grid pitch for a given translation t, we
274 // will use the grid snapper. Simply snapping the value t to the grid will do, but
275 // only if the origin of the grid is at (0,0). If it's not then compensate for this
276 // in the translation t
277 Geom::Point const t_offset = t + grid->origin;
278 SnappedConstraints sc;
279 // Only the first three parameters are being used for grid snappers
280 snapper->freeSnap(sc, Inkscape::SnapCandidatePoint(t_offset, Inkscape::SNAPSOURCE_GRID_PITCH),Geom::OptRect(), NULL, NULL);
281 // Find the best snap for this grid, including intersections of the grid-lines
282 bool old_val = _snapindicator;
283 _snapindicator = false;
284 Inkscape::SnappedPoint s = findBestSnap(Inkscape::SnapCandidatePoint(t_offset, Inkscape::SNAPSOURCE_GRID_PITCH), sc, false, false, true);
285 _snapindicator = old_val;
286 if (s.getSnapped() && (s.getSnapDistance() < nearest_distance)) {
287 // use getSnapDistance() instead of getWeightedDistance() here because the pointer's position
288 // doesn't tell us anything about which node to snap
289 success = true;
290 nearest_multiple = s.getPoint() - to_2geom(grid->origin);
291 nearest_distance = s.getSnapDistance();
292 bestSnappedPoint = s;
293 }
294 }
295 }
297 if (success) {
298 bestSnappedPoint.setPoint(origin + nearest_multiple);
299 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
300 return nearest_multiple;
301 }
302 }
304 return t;
305 }
307 /**
308 * \brief Try to snap a point along a constraint line to grids, guides or objects.
309 *
310 * Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
311 * i.e. snap in a specific direction on the two dimensional canvas to the nearest
312 * snap target.
313 *
314 * constrainedSnapReturnByRef() is equal in snapping behavior to
315 * constrainedSnap(), but the former returns the snapped point trough the referenced
316 * parameter p. This parameter p initially contains the position of the snap
317 * source and will we overwritten by the target position if snapping has occurred.
318 * This makes snapping transparent to the calling code. If this is not desired
319 * because either the calling code must know whether snapping has occurred, or
320 * because the original position should not be touched, then constrainedSnap() should
321 * be called instead.
322 *
323 * PS:
324 * 1) SnapManager::setup() must have been called before calling this method,
325 * but only once for a set of points
326 * 2) Only to be used when a single source point is to be snapped; it assumes
327 * that source_num = 0, which is inefficient when snapping sets our source points
329 *
330 * \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred
331 * \param source_type Detailed description of the source type, will be used by the snap indicator
332 * \param constraint The direction or line along which snapping must occur
333 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
334 */
336 void SnapManager::constrainedSnapReturnByRef(Geom::Point &p,
337 Inkscape::SnapSourceType const source_type,
338 Inkscape::Snapper::ConstraintLine const &constraint,
339 Geom::OptRect const &bbox_to_snap) const
340 {
341 Inkscape::SnappedPoint const s = constrainedSnap(Inkscape::SnapCandidatePoint(p, source_type, 0), constraint, bbox_to_snap);
342 s.getPoint(p);
343 }
345 /**
346 * \brief Try to snap a point along a constraint line to grids, guides or objects.
347 *
348 * Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
349 * i.e. snap in a specific direction on the two dimensional canvas to the nearest
350 * snap target. constrainedSnap is equal in snapping behavior to
351 * constrainedSnapReturnByRef(). Please read the comments of the latter for more details.
352 *
353 * PS: SnapManager::setup() must have been called before calling this method,
354 * but only once for a set of points
355 *
356 * \param p Source point to be snapped
357 * \param constraint The direction or line along which snapping must occur
358 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
359 */
361 Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::SnapCandidatePoint const &p,
362 Inkscape::Snapper::ConstraintLine const &constraint,
363 Geom::OptRect const &bbox_to_snap) const
364 {
365 // First project the mouse pointer onto the constraint
366 Geom::Point pp = constraint.projection(p.getPoint());
368 Inkscape::SnappedPoint no_snap = Inkscape::SnappedPoint(pp, p.getSourceType(), p.getSourceNum(), Inkscape::SNAPTARGET_CONSTRAINT, Geom::L2(pp - p.getPoint()), 0, false, true, false);
370 if (!someSnapperMightSnap()) {
371 // Always return point on constraint
372 return no_snap;
373 }
375 SnappedConstraints sc;
376 SnapperList const snappers = getSnappers();
377 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
378 (*i)->constrainedSnap(sc, p, bbox_to_snap, constraint, &_items_to_ignore);
379 }
381 Inkscape::SnappedPoint result = findBestSnap(p, sc, true);
383 if (result.getSnapped()) {
384 // only change the snap indicator if we really snapped to something
385 if (_snapindicator) {
386 _desktop->snapindicator->set_new_snaptarget(result);
387 }
388 return result;
389 }
390 return no_snap;
391 }
393 /**
394 * \brief Try to snap a point of a guide to another guide or to a node
395 *
396 * Try to snap a point of a guide to another guide or to a node in two degrees-
397 * of-freedom, i.e. snap in any direction on the two dimensional canvas to the
398 * nearest snap target. This method is used when dragging or rotating a guide
399 *
400 * PS: SnapManager::setup() must have been called before calling this method,
401 *
402 * \param p Current position of the point on the guide that is to be snapped; will be overwritten by the position of the snap target if snapping has occurred
403 * \param guide_normal Vector normal to the guide line
404 */
405 void SnapManager::guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const
406 {
407 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
408 return;
409 }
411 if (!(object.GuidesMightSnap() || snapprefs.getSnapToGuides())) {
412 return;
413 }
415 Inkscape::SnapCandidatePoint candidate(p, Inkscape::SNAPSOURCE_GUIDE_ORIGIN);
416 if (drag_type == SP_DRAG_ROTATE) {
417 candidate = Inkscape::SnapCandidatePoint(p, Inkscape::SNAPSOURCE_GUIDE);
418 }
420 // Snap to nodes
421 SnappedConstraints sc;
422 if (object.GuidesMightSnap()) {
423 object.guideFreeSnap(sc, p, guide_normal);
424 }
426 // Snap to guides & grid lines
427 SnapperList snappers = getGridSnappers();
428 snappers.push_back(&guide);
429 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
430 (*i)->freeSnap(sc, candidate, Geom::OptRect(), NULL, NULL);
431 }
433 // Snap to intersections of curves, but not to the curves themselves! (see _snapTranslatingGuideToNodes in object-snapper.cpp)
434 Inkscape::SnappedPoint const s = findBestSnap(candidate, sc, false, true);
436 s.getPoint(p);
437 }
439 /**
440 * \brief Try to snap a point on a guide to the intersection with another guide or a path
441 *
442 * Try to snap a point on a guide to the intersection of that guide with another
443 * guide or with a path. The snapped point will lie somewhere on the guide-line,
444 * making this is a constrained snap, i.e. in only one degree-of-freedom.
445 * This method is used when dragging the origin of the guide along the guide itself.
446 *
447 * PS: SnapManager::setup() must have been called before calling this method,
448 *
449 * \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
450 * \param guide_normal Vector normal to the guide line
451 */
453 void SnapManager::guideConstrainedSnap(Geom::Point &p, SPGuide const &guideline) const
454 {
455 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
456 return;
457 }
459 if (!(object.ThisSnapperMightSnap() || snapprefs.getSnapToGuides())) {
460 return;
461 }
463 Inkscape::SnapCandidatePoint candidate(p, Inkscape::SNAPSOURCE_GUIDE_ORIGIN, Inkscape::SNAPTARGET_UNDEFINED);
465 // Snap to nodes or paths
466 SnappedConstraints sc;
467 Inkscape::Snapper::ConstraintLine cl(guideline.point_on_line, Geom::rot90(guideline.normal_to_line));
468 if (object.ThisSnapperMightSnap()) {
469 object.constrainedSnap(sc, candidate, Geom::OptRect(), cl, NULL);
470 }
472 // Snap to guides & grid lines
473 SnapperList snappers = getGridSnappers();
474 snappers.push_back(&guide);
475 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
476 (*i)->constrainedSnap(sc, candidate, Geom::OptRect(), cl, NULL);
477 }
479 Inkscape::SnappedPoint const s = findBestSnap(candidate, sc, false);
480 s.getPoint(p);
481 }
483 /**
484 * \brief Method for snapping sets of points while they are being transformed
485 *
486 * Method for snapping sets of points while they are being transformed, when using
487 * for example the selector tool. This method is for internal use only, and should
488 * not have to be called directly. Use freeSnapTransalation(), constrainedSnapScale(),
489 * etc. instead.
490 *
491 * This is what is being done in this method: transform each point, find out whether
492 * a free snap or constrained snap is more appropriate, do the snapping, calculate
493 * some metrics to quantify the snap "distance", and see if it's better than the
494 * previous snap. Finally, the best ("nearest") snap from all these points is returned.
495 *
496 * \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.
497 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
498 * \param constrained true if the snap is constrained, e.g. for stretching or for purely horizontal translation.
499 * \param constraint The direction or line along which snapping must occur, if 'constrained' is true; otherwise undefined.
500 * \param transformation_type Type of transformation to apply to points before trying to snap them.
501 * \param transformation Description of the transformation; details depend on the type.
502 * \param origin Origin of the transformation, if applicable.
503 * \param dim Dimension to which the transformation applies, if applicable.
504 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
505 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
506 */
508 Inkscape::SnappedPoint SnapManager::_snapTransformed(
509 std::vector<Inkscape::SnapCandidatePoint> const &points,
510 Geom::Point const &pointer,
511 bool constrained,
512 Inkscape::Snapper::ConstraintLine const &constraint,
513 Transformation transformation_type,
514 Geom::Point const &transformation,
515 Geom::Point const &origin,
516 Geom::Dim2 dim,
517 bool uniform) const
518 {
519 /* We have a list of points, which we are proposing to transform in some way. We need to see
520 ** if any of these points, when transformed, snap to anything. If they do, we return the
521 ** appropriate transformation with `true'; otherwise we return the original scale with `false'.
522 */
524 /* Quick check to see if we have any snappers that are enabled
525 ** Also used to globally disable all snapping
526 */
527 if (someSnapperMightSnap() == false || points.size() == 0) {
528 return Inkscape::SnappedPoint(pointer);
529 }
531 std::vector<Inkscape::SnapCandidatePoint> transformed_points;
532 Geom::Rect bbox;
534 long source_num = 0;
535 for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = points.begin(); i != points.end(); i++) {
537 /* Work out the transformed version of this point */
538 Geom::Point transformed = _transformPoint(*i, transformation_type, transformation, origin, dim, uniform);
540 // add the current transformed point to the box hulling all transformed points
541 if (i == points.begin()) {
542 bbox = Geom::Rect(transformed, transformed);
543 } else {
544 bbox.expandTo(transformed);
545 }
547 transformed_points.push_back(Inkscape::SnapCandidatePoint(transformed, (*i).getSourceType(), source_num));
548 source_num++;
549 }
551 /* The current best transformation */
552 Geom::Point best_transformation = transformation;
554 /* The current best metric for the best transformation; lower is better, NR_HUGE
555 ** means that we haven't snapped anything.
556 */
557 Geom::Point best_scale_metric(NR_HUGE, NR_HUGE);
558 Inkscape::SnappedPoint best_snapped_point;
559 g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point
560 g_assert(best_snapped_point.getAtIntersection() == false);
562 std::vector<Inkscape::SnapCandidatePoint>::iterator j = transformed_points.begin();
565 // std::cout << std::endl;
566 bool first_free_snap = true;
567 for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = points.begin(); i != points.end(); i++) {
569 /* Snap it */
570 Inkscape::SnappedPoint snapped_point;
571 Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint;
572 Geom::Point const b = ((*i).getPoint() - origin); // vector to original point
574 if (constrained) {
575 if ((transformation_type == SCALE || transformation_type == STRETCH) && uniform) {
576 // When uniformly scaling, each point will have its own unique constraint line,
577 // running from the scaling origin to the original untransformed point. We will
578 // calculate that line here
579 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, b);
580 } else if (transformation_type == STRETCH) { // when non-uniform stretching {
581 dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i).getPoint(), component_vectors[dim]);
582 } else if (transformation_type == TRANSLATION) {
583 // When doing a constrained translation, all points will move in the same direction, i.e.
584 // either horizontally or vertically. The lines along which they move are therefore all
585 // parallel, but might not be colinear. Therefore we will have to set the point through
586 // which the constraint-line runs here, for each point individually.
587 dedicated_constraint.setPoint((*i).getPoint());
588 } // else: leave the original constraint, e.g. for skewing
589 if (transformation_type == SCALE && !uniform) {
590 g_warning("Non-uniform constrained scaling is not supported!");
591 }
592 snapped_point = constrainedSnap(*j, dedicated_constraint, bbox);
593 } else {
594 bool const c1 = fabs(b[Geom::X]) < 1e-6;
595 bool const c2 = fabs(b[Geom::Y]) < 1e-6;
596 if (transformation_type == SCALE && (c1 || c2) && !(c1 && c2)) {
597 // When scaling, a point aligned either horizontally or vertically with the origin can only
598 // move in that specific direction; therefore it should only snap in that direction, otherwise
599 // we will get snapped points with an invalid transformation
600 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, component_vectors[c1]);
601 snapped_point = constrainedSnap(*j, dedicated_constraint, bbox);
602 } else {
603 // If we have a collection of SnapCandidatePoints, with mixed constrained snapping and free snapping
604 // requirements, then freeSnap might never see the SnapCandidatePoint with source_num == 0. The freeSnap()
605 // method in the object snapper depends on this, because only for source-num == 0 the target nodes will
606 // be collected. Therefore we enforce that the first SnapCandidatePoint that is to be freeSnapped always
607 // has source_num == 0;
608 // TODO: This is a bit ugly so fix this; do we need sourcenum for anything else? if we don't then get rid
609 // of it and explicitely communicate to the object snapper that this is a first point
610 if (first_free_snap) {
611 (*j).setSourceNum(0);
612 first_free_snap = false;
613 }
614 snapped_point = freeSnap(*j, bbox);
615 }
616 }
617 // std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl;
618 snapped_point.setPointerDistance(Geom::L2(pointer - (*i).getPoint()));
620 Geom::Point result;
622 if (snapped_point.getSnapped()) {
623 /* We snapped. Find the transformation that describes where the snapped point has
624 ** ended up, and also the metric for this transformation.
625 */
626 Geom::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point
627 //Geom::Point const b = (*i - origin); // vector to original point
629 switch (transformation_type) {
630 case TRANSLATION:
631 result = snapped_point.getPoint() - (*i).getPoint();
632 /* Consider the case in which a box is almost aligned with a grid in both
633 * horizontal and vertical directions. The distance to the intersection of
634 * the grid lines will always be larger then the distance to a single grid
635 * line. If we prefer snapping to an intersection instead of to a single
636 * grid line, then we cannot use "metric = Geom::L2(result)". Therefore the
637 * snapped distance will be used as a metric. Please note that the snapped
638 * distance is defined as the distance to the nearest line of the intersection,
639 * and not to the intersection itself!
640 */
641 // Only for translations, the relevant metric will be the real snapped distance,
642 // so we don't have to do anything special here
643 break;
644 case SCALE:
645 {
646 result = Geom::Point(NR_HUGE, NR_HUGE);
647 // If this point *i is horizontally or vertically aligned with
648 // the origin of the scaling, then it will scale purely in X or Y
649 // We can therefore only calculate the scaling in this direction
650 // and the scaling factor for the other direction should remain
651 // untouched (unless scaling is uniform of course)
652 for (int index = 0; index < 2; index++) {
653 if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
654 if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
655 result[index] = a[index] / b[index]; // then calculate it!
656 }
657 // we might leave result[1-index] = NR_HUGE
658 // if scaling didn't occur in the other direction
659 }
660 }
661 if (uniform) {
662 if (fabs(result[0]) < fabs(result[1])) {
663 result[1] = result[0];
664 } else {
665 result[0] = result[1];
666 }
667 }
668 // Compare the resulting scaling with the desired scaling
669 Geom::Point scale_metric = Geom::abs(result - transformation); // One or both of its components might be NR_HUGE
670 snapped_point.setSnapDistance(std::min(scale_metric[0], scale_metric[1]));
671 snapped_point.setSecondSnapDistance(std::max(scale_metric[0], scale_metric[1]));
672 break;
673 }
674 case STRETCH:
675 result = Geom::Point(NR_HUGE, NR_HUGE);
676 if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
677 result[dim] = a[dim] / b[dim];
678 result[1-dim] = uniform ? result[dim] : 1;
679 } else { // STRETCHING might occur for this point, but only when the stretching is uniform
680 if (uniform && fabs(b[1-dim]) > 1e-6) {
681 result[1-dim] = a[1-dim] / b[1-dim];
682 result[dim] = result[1-dim];
683 }
684 }
685 // Store the metric for this transformation as a virtual distance
686 snapped_point.setSnapDistance(std::abs(result[dim] - transformation[dim]));
687 snapped_point.setSecondSnapDistance(NR_HUGE);
688 break;
689 case SKEW:
690 result[0] = (snapped_point.getPoint()[dim] - ((*i).getPoint())[dim]) / (((*i).getPoint())[1 - dim] - origin[1 - dim]); // skew factor
691 result[1] = transformation[1]; // scale factor
692 // Store the metric for this transformation as a virtual distance
693 snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
694 snapped_point.setSecondSnapDistance(NR_HUGE);
695 break;
696 default:
697 g_assert_not_reached();
698 }
700 if (best_snapped_point.isOtherSnapBetter(snapped_point, true)) {
701 best_transformation = result;
702 best_snapped_point = snapped_point;
703 }
704 }
706 j++;
707 }
709 Geom::Coord best_metric;
710 if (transformation_type == SCALE) {
711 // When scaling, don't ever exit with one of scaling components set to NR_HUGE
712 for (int index = 0; index < 2; index++) {
713 if (best_transformation[index] == NR_HUGE) {
714 if (uniform && best_transformation[1-index] < NR_HUGE) {
715 best_transformation[index] = best_transformation[1-index];
716 } else {
717 best_transformation[index] = transformation[index];
718 }
719 }
720 }
721 }
723 best_metric = best_snapped_point.getSnapDistance();
724 best_snapped_point.setTransformation(best_transformation);
725 // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
726 // These rounding errors might be caused by NRRects, see bug #1584301
727 best_snapped_point.setSnapDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
728 return best_snapped_point;
729 }
732 /**
733 * \brief Apply a translation to a set of points and try to snap freely in 2 degrees-of-freedom
734 *
735 * \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.
736 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
737 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred
738 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
739 */
741 Inkscape::SnappedPoint SnapManager::freeSnapTranslation(std::vector<Inkscape::SnapCandidatePoint> const &p,
742 Geom::Point const &pointer,
743 Geom::Point const &tr) const
744 {
745 if (p.size() == 1) {
746 Geom::Point pt = _transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
747 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
748 }
750 return _snapTransformed(p, pointer, false, Geom::Point(0,0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
751 }
753 /**
754 * \brief Apply a translation to a set of points and try to snap along a constraint
755 *
756 * \param point_type Category of points to which the source point belongs: node or bounding box.
757 * \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.
758 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
759 * \param constraint The direction or line along which snapping must occur.
760 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred.
761 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
762 */
764 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslation(std::vector<Inkscape::SnapCandidatePoint> const &p,
765 Geom::Point const &pointer,
766 Inkscape::Snapper::ConstraintLine const &constraint,
767 Geom::Point const &tr) const
768 {
769 if (p.size() == 1) {
770 Geom::Point pt = _transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
771 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
772 }
774 return _snapTransformed(p, pointer, true, constraint, TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
775 }
778 /**
779 * \brief Apply a scaling to a set of points and try to snap freely in 2 degrees-of-freedom
780 *
781 * \param point_type Category of points to which the source point belongs: node or bounding box.
782 * \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.
783 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
784 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
785 * \param o Origin of the scaling
786 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
787 */
789 Inkscape::SnappedPoint SnapManager::freeSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
790 Geom::Point const &pointer,
791 Geom::Scale const &s,
792 Geom::Point const &o) const
793 {
794 if (p.size() == 1) {
795 Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
796 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
797 }
799 return _snapTransformed(p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
800 }
803 /**
804 * \brief Apply a scaling to a set of points and snap such that the aspect ratio of the selection is preserved
805 *
806 * \param point_type Category of points to which the source point belongs: node or bounding box.
807 * \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.
808 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
809 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
810 * \param o Origin of the scaling
811 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
812 */
814 Inkscape::SnappedPoint SnapManager::constrainedSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
815 Geom::Point const &pointer,
816 Geom::Scale const &s,
817 Geom::Point const &o) const
818 {
819 // When constrained scaling, only uniform scaling is supported.
820 if (p.size() == 1) {
821 Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
822 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
823 }
825 return _snapTransformed(p, pointer, true, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
826 }
828 /**
829 * \brief Apply a stretch to a set of points and snap such that the direction of the stretch is preserved
830 *
831 * \param point_type Category of points to which the source point belongs: node or bounding box.
832 * \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
833 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
834 * \param s Proposed stretch; the final stretch can only be calculated after snapping has occurred
835 * \param o Origin of the stretching
836 * \param d Dimension in which to apply proposed stretch.
837 * \param u true if the stretch should be uniform (i.e. to be applied equally in both dimensions)
838 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
839 */
841 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(std::vector<Inkscape::SnapCandidatePoint> const &p,
842 Geom::Point const &pointer,
843 Geom::Coord const &s,
844 Geom::Point const &o,
845 Geom::Dim2 d,
846 bool u) const
847 {
848 if (p.size() == 1) {
849 Geom::Point pt = _transformPoint(p.at(0), STRETCH, Geom::Point(s, s), o, d, u);
850 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
851 }
853 return _snapTransformed(p, pointer, true, Geom::Point(0,0), STRETCH, Geom::Point(s, s), o, d, u);
854 }
856 /**
857 * \brief Apply a skew to a set of points and snap such that the direction of the skew is preserved
858 *
859 * \param point_type Category of points to which the source point belongs: node or bounding box.
860 * \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.
861 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
862 * \param constraint The direction or line along which snapping must occur.
863 * \param s Proposed skew; the final skew can only be calculated after snapping has occurred
864 * \param o Origin of the proposed skew
865 * \param d Dimension in which to apply proposed skew.
866 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
867 */
869 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(std::vector<Inkscape::SnapCandidatePoint> const &p,
870 Geom::Point const &pointer,
871 Inkscape::Snapper::ConstraintLine const &constraint,
872 Geom::Point const &s,
873 Geom::Point const &o,
874 Geom::Dim2 d) const
875 {
876 // "s" contains skew factor in s[0], and scale factor in s[1]
878 // Snapping the nodes of the bounding box of a selection that is being transformed, will only work if
879 // the transformation of the bounding box is equal to the transformation of the individual nodes. This is
880 // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
881 // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
882 // of bounding boxes is not allowed here.
883 if (p.size() > 0) {
884 g_assert(!(p.at(0).getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY));
885 }
887 if (p.size() == 1) {
888 Geom::Point pt = _transformPoint(p.at(0), SKEW, s, o, d, false);
889 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
890 }
892 return _snapTransformed(p, pointer, true, constraint, SKEW, s, o, d, false);
893 }
895 /**
896 * \brief Given a set of possible snap targets, find the best target (which is not necessarily
897 * also the nearest target), and show the snap indicator if requested
898 *
899 * \param p Source point to be snapped
900 * \param sc A structure holding all snap targets that have been found so far
901 * \param constrained True if the snap is constrained, e.g. for stretching or for purely horizontal translation.
902 * \param noCurves If true, then do consider snapping to intersections of curves, but not to the curves themselves
903 * \param allowOffScreen If true, then snapping to points which are off the screen is allowed (needed for example when pasting to the grid)
904 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
905 */
907 Inkscape::SnappedPoint SnapManager::findBestSnap(Inkscape::SnapCandidatePoint const &p,
908 SnappedConstraints const &sc,
909 bool constrained,
910 bool noCurves,
911 bool allowOffScreen) const
912 {
915 /*
916 std::cout << "Type and number of snapped constraints: " << std::endl;
917 std::cout << " Points : " << sc.points.size() << std::endl;
918 std::cout << " Lines : " << sc.lines.size() << std::endl;
919 std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
920 std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
921 std::cout << " Curves : " << sc.curves.size()<< std::endl;
922 */
924 // Store all snappoints
925 std::list<Inkscape::SnappedPoint> sp_list;
927 // search for the closest snapped point
928 Inkscape::SnappedPoint closestPoint;
929 if (getClosestSP(sc.points, closestPoint)) {
930 sp_list.push_back(closestPoint);
931 }
933 // search for the closest snapped curve
934 if (!noCurves) {
935 Inkscape::SnappedCurve closestCurve;
936 if (getClosestCurve(sc.curves, closestCurve)) {
937 sp_list.push_back(Inkscape::SnappedPoint(closestCurve));
938 }
939 }
941 if (snapprefs.getSnapIntersectionCS()) {
942 // search for the closest snapped intersection of curves
943 Inkscape::SnappedPoint closestCurvesIntersection;
944 if (getClosestIntersectionCS(sc.curves, p.getPoint(), closestCurvesIntersection, _desktop->dt2doc())) {
945 closestCurvesIntersection.setSource(p.getSourceType());
946 sp_list.push_back(closestCurvesIntersection);
947 }
948 }
950 // search for the closest snapped grid line
951 Inkscape::SnappedLine closestGridLine;
952 if (getClosestSL(sc.grid_lines, closestGridLine)) {
953 sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
954 }
956 // search for the closest snapped guide line
957 Inkscape::SnappedLine closestGuideLine;
958 if (getClosestSL(sc.guide_lines, closestGuideLine)) {
959 sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
960 }
962 // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
963 // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
965 // When doing a constrained snap however, we're already at an intersection of the constrained line and
966 // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
967 // no need to look for additional intersections
968 if (!constrained) {
969 // search for the closest snapped intersection of grid lines
970 Inkscape::SnappedPoint closestGridPoint;
971 if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
972 closestGridPoint.setSource(p.getSourceType());
973 closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
974 sp_list.push_back(closestGridPoint);
975 }
977 // search for the closest snapped intersection of guide lines
978 Inkscape::SnappedPoint closestGuidePoint;
979 if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
980 closestGuidePoint.setSource(p.getSourceType());
981 closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
982 sp_list.push_back(closestGuidePoint);
983 }
985 // search for the closest snapped intersection of grid with guide lines
986 if (snapprefs.getSnapIntersectionGG()) {
987 Inkscape::SnappedPoint closestGridGuidePoint;
988 if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
989 closestGridGuidePoint.setSource(p.getSourceType());
990 closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
991 sp_list.push_back(closestGridGuidePoint);
992 }
993 }
994 }
996 // now let's see which snapped point gets a thumbs up
997 Inkscape::SnappedPoint bestSnappedPoint(p.getPoint());
998 // std::cout << "Finding the best snap..." << std::endl;
999 for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
1000 // std::cout << "sp = " << (*i).getPoint() << " | source = " << (*i).getSource() << " | target = " << (*i).getTarget();
1001 bool onScreen = _desktop->get_display_area().contains((*i).getPoint());
1002 if (onScreen || allowOffScreen) { // Only snap to points which are not off the screen
1003 if ((*i).getSnapDistance() <= (*i).getTolerance()) { // Only snap to points within snapping range
1004 // if it's the first point, or if it is closer than the best snapped point so far
1005 if (i == sp_list.begin() || bestSnappedPoint.isOtherSnapBetter(*i, false)) {
1006 // then prefer this point over the previous one
1007 bestSnappedPoint = *i;
1008 }
1009 }
1010 }
1011 // std::cout << std::endl;
1012 }
1014 // Update the snap indicator, if requested
1015 if (_snapindicator) {
1016 if (bestSnappedPoint.getSnapped()) {
1017 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
1018 } else {
1019 _desktop->snapindicator->remove_snaptarget();
1020 }
1021 }
1023 // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl;
1024 return bestSnappedPoint;
1025 }
1027 /// Convenience shortcut when there is only one item to ignore
1028 void SnapManager::setup(SPDesktop const *desktop,
1029 bool snapindicator,
1030 SPItem const *item_to_ignore,
1031 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1032 SPGuide *guide_to_ignore)
1033 {
1034 g_assert(desktop != NULL);
1035 _items_to_ignore.clear();
1036 _items_to_ignore.push_back(item_to_ignore);
1037 _desktop = desktop;
1038 _snapindicator = snapindicator;
1039 _unselected_nodes = unselected_nodes;
1040 _guide_to_ignore = guide_to_ignore;
1041 }
1043 /**
1044 * \brief Prepare the snap manager for the actual snapping, which includes building a list of snap targets
1045 * to ignore and toggling the snap indicator
1046 *
1047 * There are two overloaded setup() methods, of which the other one only allows for a single item to be ignored
1048 * whereas this one will take a list of items to ignore
1049 *
1050 * \param desktop Reference to the desktop to which this snap manager is attached
1051 * \param snapindicator If true then a snap indicator will be displayed automatically (when enabled in the preferences)
1052 * \param items_to_ignore These items will not be snapped to, e.g. the items that are currently being dragged. This avoids "self-snapping"
1053 * \param unselected_nodes Stationary nodes of the path that is currently being edited in the node tool and
1054 * that can be snapped too. Nodes not in this list will not be snapped to, to avoid "self-snapping". Of each
1055 * unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored
1056 * \param guide_to_ignore Guide that is currently being dragged and should not be snapped to
1057 */
1059 void SnapManager::setup(SPDesktop const *desktop,
1060 bool snapindicator,
1061 std::vector<SPItem const *> &items_to_ignore,
1062 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1063 SPGuide *guide_to_ignore)
1064 {
1065 g_assert(desktop != NULL);
1066 _items_to_ignore = items_to_ignore;
1067 _desktop = desktop;
1068 _snapindicator = snapindicator;
1069 _unselected_nodes = unselected_nodes;
1070 _guide_to_ignore = guide_to_ignore;
1071 }
1073 /// Setup, taking the list of items to ignore from the desktop's selection.
1074 void SnapManager::setupIgnoreSelection(SPDesktop const *desktop,
1075 bool snapindicator,
1076 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1077 SPGuide *guide_to_ignore)
1078 {
1079 _desktop = desktop;
1080 _snapindicator = snapindicator;
1081 _unselected_nodes = unselected_nodes;
1082 _guide_to_ignore = guide_to_ignore;
1083 _items_to_ignore.clear();
1085 Inkscape::Selection *sel = _desktop->selection;
1086 GSList const *items = sel->itemList();
1087 for (GSList *i = const_cast<GSList*>(items); i; i = i->next) {
1088 _items_to_ignore.push_back(static_cast<SPItem const *>(i->data));
1089 }
1090 }
1092 SPDocument *SnapManager::getDocument() const
1093 {
1094 return _named_view->document;
1095 }
1097 /**
1098 * \brief Takes an untransformed point, applies the given transformation, and returns the transformed point. Eliminates lots of duplicated code
1099 *
1100 * \param p The untransformed position of the point, paired with an identifier of the type of the snap source.
1101 * \param transformation_type Type of transformation to apply.
1102 * \param transformation Mathematical description of the transformation; details depend on the type.
1103 * \param origin Origin of the transformation, if applicable.
1104 * \param dim Dimension to which the transformation applies, if applicable.
1105 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
1106 * \return The position of the point after transformation
1107 */
1109 Geom::Point SnapManager::_transformPoint(Inkscape::SnapCandidatePoint const &p,
1110 Transformation const transformation_type,
1111 Geom::Point const &transformation,
1112 Geom::Point const &origin,
1113 Geom::Dim2 const dim,
1114 bool const uniform) const
1115 {
1116 /* Work out the transformed version of this point */
1117 Geom::Point transformed;
1118 switch (transformation_type) {
1119 case TRANSLATION:
1120 transformed = p.getPoint() + transformation;
1121 break;
1122 case SCALE:
1123 transformed = (p.getPoint() - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
1124 break;
1125 case STRETCH:
1126 {
1127 Geom::Scale s(1, 1);
1128 if (uniform)
1129 s[Geom::X] = s[Geom::Y] = transformation[dim];
1130 else {
1131 s[dim] = transformation[dim];
1132 s[1 - dim] = 1;
1133 }
1134 transformed = ((p.getPoint() - origin) * s) + origin;
1135 break;
1136 }
1137 case SKEW:
1138 // Apply the skew factor
1139 transformed[dim] = (p.getPoint())[dim] + transformation[0] * ((p.getPoint())[1 - dim] - origin[1 - dim]);
1140 // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
1141 // Apply that scale factor here
1142 transformed[1-dim] = (p.getPoint() - origin)[1 - dim] * transformation[1] + origin[1 - dim];
1143 break;
1144 default:
1145 g_assert_not_reached();
1146 }
1148 return transformed;
1149 }
1151 /**
1152 * \brief Mark the location of the snap source (not the snap target!) on the canvas by drawing a symbol
1153 *
1154 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
1155 * \param p The transformed position of the source point, paired with an identifier of the type of the snap source.
1156 */
1158 void SnapManager::_displaySnapsource(Inkscape::SnapCandidatePoint const &p) const {
1160 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
1161 if (prefs->getBool("/options/snapclosestonly/value")) {
1162 bool p_is_a_node = p.getSourceType() & Inkscape::SNAPSOURCE_NODE_CATEGORY;
1163 bool p_is_a_bbox = p.getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY;
1165 if (snapprefs.getSnapEnabledGlobally() && ((p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) {
1166 _desktop->snapindicator->set_new_snapsource(p);
1167 } else {
1168 _desktop->snapindicator->remove_snapsource();
1169 }
1170 }
1171 }
1173 /*
1174 Local Variables:
1175 mode:c++
1176 c-file-style:"stroustrup"
1177 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1178 indent-tabs-mode:nil
1179 fill-column:99
1180 End:
1181 */
1182 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :