352683623fe16079f8aa8f911ae31360dadac4df
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);
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, false);
370 if (!someSnapperMightSnap()) {
371 // The constraint should always be enforced, so we return pp here instead of p
372 if (_snapindicator) {
373 _desktop->snapindicator->set_new_snaptarget(no_snap);
374 }
375 return no_snap;
376 }
378 // Then try to snap the projected point
379 Inkscape::SnapCandidatePoint candidate(pp, p.getSourceType(), p.getSourceNum(), Inkscape::SNAPTARGET_UNDEFINED, Geom::Rect());
381 SnappedConstraints sc;
382 SnapperList const snappers = getSnappers();
383 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
384 (*i)->constrainedSnap(sc, candidate, bbox_to_snap, constraint, &_items_to_ignore);
385 }
387 Inkscape::SnappedPoint result = findBestSnap(candidate, sc, true);
389 if (result.getSnapped()) {
390 return result;
391 }
393 // The constraint should always be enforced, so we return pp here instead of p
394 if (_snapindicator) {
395 _desktop->snapindicator->set_new_snaptarget(no_snap);
396 }
397 return no_snap;
398 }
400 /**
401 * \brief Try to snap a point of a guide to another guide or to a node
402 *
403 * Try to snap a point of a guide to another guide or to a node in two degrees-
404 * of-freedom, i.e. snap in any direction on the two dimensional canvas to the
405 * nearest snap target. This method is used when dragging or rotating a guide
406 *
407 * PS: SnapManager::setup() must have been called before calling this method,
408 *
409 * \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
410 * \param guide_normal Vector normal to the guide line
411 */
412 void SnapManager::guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const
413 {
414 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
415 return;
416 }
418 if (!(object.GuidesMightSnap() || snapprefs.getSnapToGuides())) {
419 return;
420 }
422 Inkscape::SnapCandidatePoint candidate(p, Inkscape::SNAPSOURCE_GUIDE_ORIGIN);
423 if (drag_type == SP_DRAG_ROTATE) {
424 candidate = Inkscape::SnapCandidatePoint(p, Inkscape::SNAPSOURCE_GUIDE);
425 }
427 // Snap to nodes
428 SnappedConstraints sc;
429 if (object.GuidesMightSnap()) {
430 object.guideFreeSnap(sc, p, guide_normal);
431 }
433 // Snap to guides & grid lines
434 SnapperList snappers = getGridSnappers();
435 snappers.push_back(&guide);
436 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
437 (*i)->freeSnap(sc, candidate, Geom::OptRect(), NULL, NULL);
438 }
440 // Snap to intersections of curves, but not to the curves themselves! (see _snapTranslatingGuideToNodes in object-snapper.cpp)
441 Inkscape::SnappedPoint const s = findBestSnap(candidate, sc, false, true);
443 s.getPoint(p);
444 }
446 /**
447 * \brief Try to snap a point on a guide to the intersection with another guide or a path
448 *
449 * Try to snap a point on a guide to the intersection of that guide with another
450 * guide or with a path. The snapped point will lie somewhere on the guide-line,
451 * making this is a constrained snap, i.e. in only one degree-of-freedom.
452 * This method is used when dragging the origin of the guide along the guide itself.
453 *
454 * PS: SnapManager::setup() must have been called before calling this method,
455 *
456 * \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
457 * \param guide_normal Vector normal to the guide line
458 */
460 void SnapManager::guideConstrainedSnap(Geom::Point &p, SPGuide const &guideline) const
461 {
462 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
463 return;
464 }
466 if (!(object.ThisSnapperMightSnap() || snapprefs.getSnapToGuides())) {
467 return;
468 }
470 Inkscape::SnapCandidatePoint candidate(p, Inkscape::SNAPSOURCE_GUIDE_ORIGIN, Inkscape::SNAPTARGET_UNDEFINED);
472 // Snap to nodes or paths
473 SnappedConstraints sc;
474 Inkscape::Snapper::ConstraintLine cl(guideline.point_on_line, Geom::rot90(guideline.normal_to_line));
475 if (object.ThisSnapperMightSnap()) {
476 object.constrainedSnap(sc, candidate, Geom::OptRect(), cl, NULL);
477 }
479 // Snap to guides & grid lines
480 SnapperList snappers = getGridSnappers();
481 snappers.push_back(&guide);
482 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
483 (*i)->constrainedSnap(sc, candidate, Geom::OptRect(), cl, NULL);
484 }
486 Inkscape::SnappedPoint const s = findBestSnap(candidate, sc, false);
487 s.getPoint(p);
488 }
490 /**
491 * \brief Method for snapping sets of points while they are being transformed
492 *
493 * Method for snapping sets of points while they are being transformed, when using
494 * for example the selector tool. This method is for internal use only, and should
495 * not have to be called directly. Use freeSnapTransalation(), constrainedSnapScale(),
496 * etc. instead.
497 *
498 * This is what is being done in this method: transform each point, find out whether
499 * a free snap or constrained snap is more appropriate, do the snapping, calculate
500 * some metrics to quantify the snap "distance", and see if it's better than the
501 * previous snap. Finally, the best ("nearest") snap from all these points is returned.
502 *
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 std::vector<Inkscape::SnapCandidatePoint> const &points,
517 Geom::Point const &pointer,
518 bool constrained,
519 Inkscape::Snapper::ConstraintLine const &constraint,
520 Transformation transformation_type,
521 Geom::Point const &transformation,
522 Geom::Point const &origin,
523 Geom::Dim2 dim,
524 bool uniform) const
525 {
526 /* We have a list of points, which we are proposing to transform in some way. We need to see
527 ** if any of these points, when transformed, snap to anything. If they do, we return the
528 ** appropriate transformation with `true'; otherwise we return the original scale with `false'.
529 */
531 /* Quick check to see if we have any snappers that are enabled
532 ** Also used to globally disable all snapping
533 */
534 if (someSnapperMightSnap() == false) {
535 return Inkscape::SnappedPoint(pointer);
536 }
538 std::vector<Inkscape::SnapCandidatePoint> transformed_points;
539 Geom::Rect bbox;
541 long source_num = 0;
542 for (std::vector<Inkscape::SnapCandidatePoint>::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(Inkscape::SnapCandidatePoint(transformed, (*i).getSourceType(), source_num));
555 source_num++;
556 }
558 /* The current best transformation */
559 Geom::Point best_transformation = transformation;
561 /* The current best metric for the best transformation; lower is better, NR_HUGE
562 ** means that we haven't snapped anything.
563 */
564 Geom::Point best_scale_metric(NR_HUGE, NR_HUGE);
565 Inkscape::SnappedPoint best_snapped_point;
566 g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point
567 g_assert(best_snapped_point.getAtIntersection() == false);
569 std::vector<Inkscape::SnapCandidatePoint>::const_iterator j = transformed_points.begin();
572 // std::cout << std::endl;
573 for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = points.begin(); i != points.end(); i++) {
575 /* Snap it */
576 Inkscape::SnappedPoint snapped_point;
577 Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint;
578 Geom::Point const b = ((*i).getPoint() - origin); // vector to original point
580 if (constrained) {
581 if ((transformation_type == SCALE || transformation_type == STRETCH) && uniform) {
582 // When uniformly scaling, each point will have its own unique constraint line,
583 // running from the scaling origin to the original untransformed point. We will
584 // calculate that line here
585 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, b);
586 } else if (transformation_type == STRETCH) { // when non-uniform stretching {
587 dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i).getPoint(), component_vectors[dim]);
588 } else if (transformation_type == TRANSLATION) {
589 // When doing a constrained translation, all points will move in the same direction, i.e.
590 // either horizontally or vertically. The lines along which they move are therefore all
591 // parallel, but might not be colinear. Therefore we will have to set the point through
592 // which the constraint-line runs here, for each point individually.
593 dedicated_constraint.setPoint((*i).getPoint());
594 } // else: leave the original constraint, e.g. for skewing
595 if (transformation_type == SCALE && !uniform) {
596 g_warning("Non-uniform constrained scaling is not supported!");
597 }
598 snapped_point = constrainedSnap(*j, dedicated_constraint, bbox);
599 } else {
600 bool const c1 = fabs(b[Geom::X]) < 1e-6;
601 bool const c2 = fabs(b[Geom::Y]) < 1e-6;
602 if (transformation_type == SCALE && (c1 || c2) && !(c1 && c2)) {
603 // When scaling, a point aligned either horizontally or vertically with the origin can only
604 // move in that specific direction; therefore it should only snap in that direction, otherwise
605 // we will get snapped points with an invalid transformation
606 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, component_vectors[c1]);
607 snapped_point = constrainedSnap(*j, dedicated_constraint, bbox);
608 } else {
609 snapped_point = freeSnap(*j, bbox);
610 }
611 }
612 // std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl;
613 snapped_point.setPointerDistance(Geom::L2(pointer - (*i).getPoint()));
615 Geom::Point result;
617 if (snapped_point.getSnapped()) {
618 /* We snapped. Find the transformation that describes where the snapped point has
619 ** ended up, and also the metric for this transformation.
620 */
621 Geom::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point
622 //Geom::Point const b = (*i - origin); // vector to original point
624 switch (transformation_type) {
625 case TRANSLATION:
626 result = snapped_point.getPoint() - (*i).getPoint();
627 /* Consider the case in which a box is almost aligned with a grid in both
628 * horizontal and vertical directions. The distance to the intersection of
629 * the grid lines will always be larger then the distance to a single grid
630 * line. If we prefer snapping to an intersection instead of to a single
631 * grid line, then we cannot use "metric = Geom::L2(result)". Therefore the
632 * snapped distance will be used as a metric. Please note that the snapped
633 * distance is defined as the distance to the nearest line of the intersection,
634 * and not to the intersection itself!
635 */
636 // Only for translations, the relevant metric will be the real snapped distance,
637 // so we don't have to do anything special here
638 break;
639 case SCALE:
640 {
641 result = Geom::Point(NR_HUGE, NR_HUGE);
642 // If this point *i is horizontally or vertically aligned with
643 // the origin of the scaling, then it will scale purely in X or Y
644 // We can therefore only calculate the scaling in this direction
645 // and the scaling factor for the other direction should remain
646 // untouched (unless scaling is uniform ofcourse)
647 for (int index = 0; index < 2; index++) {
648 if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
649 if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
650 result[index] = a[index] / b[index]; // then calculate it!
651 }
652 // we might leave result[1-index] = NR_HUGE
653 // if scaling didn't occur in the other direction
654 }
655 }
656 if (uniform) {
657 if (fabs(result[0]) < fabs(result[1])) {
658 result[1] = result[0];
659 } else {
660 result[0] = result[1];
661 }
662 }
663 // Compare the resulting scaling with the desired scaling
664 Geom::Point scale_metric = Geom::abs(result - transformation); // One or both of its components might be NR_HUGE
665 snapped_point.setSnapDistance(std::min(scale_metric[0], scale_metric[1]));
666 snapped_point.setSecondSnapDistance(std::max(scale_metric[0], scale_metric[1]));
667 break;
668 }
669 case STRETCH:
670 result = Geom::Point(NR_HUGE, NR_HUGE);
671 if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
672 result[dim] = a[dim] / b[dim];
673 result[1-dim] = uniform ? result[dim] : 1;
674 } else { // STRETCHING might occur for this point, but only when the stretching is uniform
675 if (uniform && fabs(b[1-dim]) > 1e-6) {
676 result[1-dim] = a[1-dim] / b[1-dim];
677 result[dim] = result[1-dim];
678 }
679 }
680 // Store the metric for this transformation as a virtual distance
681 snapped_point.setSnapDistance(std::abs(result[dim] - transformation[dim]));
682 snapped_point.setSecondSnapDistance(NR_HUGE);
683 break;
684 case SKEW:
685 result[0] = (snapped_point.getPoint()[dim] - ((*i).getPoint())[dim]) / (((*i).getPoint())[1 - dim] - origin[1 - dim]); // skew factor
686 result[1] = transformation[1]; // scale factor
687 // Store the metric for this transformation as a virtual distance
688 snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
689 snapped_point.setSecondSnapDistance(NR_HUGE);
690 break;
691 default:
692 g_assert_not_reached();
693 }
695 // When scaling, we're considering the best transformation in each direction separately. We will have a metric in each
696 // direction, whereas for all other transformation we only a single one-dimensional metric. That's why we need to handle
697 // the scaling metric differently
698 if (best_snapped_point.isOtherSnapBetter(snapped_point, true)) {
699 best_transformation = result;
700 best_snapped_point = snapped_point;
701 }
702 }
704 j++;
705 }
707 Geom::Coord best_metric;
708 if (transformation_type == SCALE) {
709 // When scaling, don't ever exit with one of scaling components set to NR_HUGE
710 for (int index = 0; index < 2; index++) {
711 if (best_transformation[index] == NR_HUGE) {
712 if (uniform && best_transformation[1-index] < NR_HUGE) {
713 best_transformation[index] = best_transformation[1-index];
714 } else {
715 best_transformation[index] = transformation[index];
716 }
717 }
718 }
719 }
721 best_metric = best_snapped_point.getSnapDistance();
722 best_snapped_point.setTransformation(best_transformation);
723 // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
724 // These rounding errors might be caused by NRRects, see bug #1584301
725 best_snapped_point.setSnapDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
726 return best_snapped_point;
727 }
730 /**
731 * \brief Apply a translation to a set of points and try to snap freely in 2 degrees-of-freedom
732 *
733 * \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.
734 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
735 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred
736 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
737 */
739 Inkscape::SnappedPoint SnapManager::freeSnapTranslation(std::vector<Inkscape::SnapCandidatePoint> const &p,
740 Geom::Point const &pointer,
741 Geom::Point const &tr) const
742 {
743 if (p.size() == 1) {
744 Geom::Point pt = _transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
745 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
746 }
748 return _snapTransformed(p, pointer, false, Geom::Point(0,0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
749 }
751 /**
752 * \brief Apply a translation to a set of points and try to snap along a constraint
753 *
754 * \param point_type Category of points to which the source point belongs: node or bounding box.
755 * \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.
756 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
757 * \param constraint The direction or line along which snapping must occur.
758 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred.
759 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
760 */
762 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslation(std::vector<Inkscape::SnapCandidatePoint> const &p,
763 Geom::Point const &pointer,
764 Inkscape::Snapper::ConstraintLine const &constraint,
765 Geom::Point const &tr) const
766 {
767 if (p.size() == 1) {
768 Geom::Point pt = _transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
769 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
770 }
772 return _snapTransformed(p, pointer, true, constraint, TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
773 }
776 /**
777 * \brief Apply a scaling to a set of points and try to snap freely in 2 degrees-of-freedom
778 *
779 * \param point_type Category of points to which the source point belongs: node or bounding box.
780 * \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.
781 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
782 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
783 * \param o Origin of the scaling
784 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
785 */
787 Inkscape::SnappedPoint SnapManager::freeSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
788 Geom::Point const &pointer,
789 Geom::Scale const &s,
790 Geom::Point const &o) const
791 {
792 if (p.size() == 1) {
793 Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
794 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
795 }
797 return _snapTransformed(p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
798 }
801 /**
802 * \brief Apply a scaling to a set of points and snap such that the aspect ratio of the selection is preserved
803 *
804 * \param point_type Category of points to which the source point belongs: node or bounding box.
805 * \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.
806 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
807 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
808 * \param o Origin of the scaling
809 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
810 */
812 Inkscape::SnappedPoint SnapManager::constrainedSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
813 Geom::Point const &pointer,
814 Geom::Scale const &s,
815 Geom::Point const &o) const
816 {
817 // When constrained scaling, only uniform scaling is supported.
818 if (p.size() == 1) {
819 Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
820 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
821 }
823 return _snapTransformed(p, pointer, true, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
824 }
826 /**
827 * \brief Apply a stretch to a set of points and snap such that the direction of the stretch is preserved
828 *
829 * \param point_type Category of points to which the source point belongs: node or bounding box.
830 * \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.
831 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
832 * \param s Proposed stretch; the final stretch can only be calculated after snapping has occurred
833 * \param o Origin of the stretching
834 * \param d Dimension in which to apply proposed stretch.
835 * \param u true if the stretch should be uniform (i.e. to be applied equally in both dimensions)
836 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
837 */
839 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(std::vector<Inkscape::SnapCandidatePoint> const &p,
840 Geom::Point const &pointer,
841 Geom::Coord const &s,
842 Geom::Point const &o,
843 Geom::Dim2 d,
844 bool u) const
845 {
846 if (p.size() == 1) {
847 Geom::Point pt = _transformPoint(p.at(0), STRETCH, Geom::Point(s, s), o, d, u);
848 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
849 }
851 return _snapTransformed(p, pointer, true, Geom::Point(0,0), STRETCH, Geom::Point(s, s), o, d, u);
852 }
854 /**
855 * \brief Apply a skew to a set of points and snap such that the direction of the skew is preserved
856 *
857 * \param point_type Category of points to which the source point belongs: node or bounding box.
858 * \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.
859 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
860 * \param constraint The direction or line along which snapping must occur.
861 * \param s Proposed skew; the final skew can only be calculated after snapping has occurred
862 * \param o Origin of the proposed skew
863 * \param d Dimension in which to apply proposed skew.
864 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
865 */
867 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(std::vector<Inkscape::SnapCandidatePoint> const &p,
868 Geom::Point const &pointer,
869 Inkscape::Snapper::ConstraintLine const &constraint,
870 Geom::Point const &s,
871 Geom::Point const &o,
872 Geom::Dim2 d) const
873 {
874 // "s" contains skew factor in s[0], and scale factor in s[1]
876 // Snapping the nodes of the bounding box of a selection that is being transformed, will only work if
877 // the transformation of the bounding box is equal to the transformation of the individual nodes. This is
878 // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
879 // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
880 // of bounding boxes is not allowed here.
881 if (p.size() > 0) {
882 g_assert(!(p.at(0).getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY));
883 }
885 if (p.size() == 1) {
886 Geom::Point pt = _transformPoint(p.at(0), SKEW, s, o, d, false);
887 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
888 }
890 return _snapTransformed(p, pointer, true, constraint, SKEW, s, o, d, false);
891 }
893 /**
894 * \brief Given a set of possible snap targets, find the best target (which is not necessarily
895 * also the nearest target), and show the snap indicator if requested
896 *
897 * \param p Source point to be snapped
898 * \param sc A structure holding all snap targets that have been found so far
899 * \param constrained True if the snap is constrained, e.g. for stretching or for purely horizontal translation.
900 * \param noCurves If true, then do consider snapping to intersections of curves, but not to the curves themselves
901 * \param allowOffScreen If true, then snapping to points which are off the screen is allowed (needed for example when pasting to the grid)
902 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
903 */
905 Inkscape::SnappedPoint SnapManager::findBestSnap(Inkscape::SnapCandidatePoint const &p,
906 SnappedConstraints const &sc,
907 bool constrained,
908 bool noCurves,
909 bool allowOffScreen) const
910 {
912 /*
913 std::cout << "Type and number of snapped constraints: " << std::endl;
914 std::cout << " Points : " << sc.points.size() << std::endl;
915 std::cout << " Lines : " << sc.lines.size() << std::endl;
916 std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
917 std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
918 std::cout << " Curves : " << sc.curves.size()<< std::endl;
919 */
921 // Store all snappoints
922 std::list<Inkscape::SnappedPoint> sp_list;
924 // search for the closest snapped point
925 Inkscape::SnappedPoint closestPoint;
926 if (getClosestSP(sc.points, closestPoint)) {
927 sp_list.push_back(closestPoint);
928 }
930 // search for the closest snapped curve
931 if (!noCurves) {
932 Inkscape::SnappedCurve closestCurve;
933 if (getClosestCurve(sc.curves, closestCurve)) {
934 sp_list.push_back(Inkscape::SnappedPoint(closestCurve));
935 }
936 }
938 if (snapprefs.getSnapIntersectionCS()) {
939 // search for the closest snapped intersection of curves
940 Inkscape::SnappedPoint closestCurvesIntersection;
941 if (getClosestIntersectionCS(sc.curves, p.getPoint(), closestCurvesIntersection, _desktop->dt2doc())) {
942 closestCurvesIntersection.setSource(p.getSourceType());
943 sp_list.push_back(closestCurvesIntersection);
944 }
945 }
947 // search for the closest snapped grid line
948 Inkscape::SnappedLine closestGridLine;
949 if (getClosestSL(sc.grid_lines, closestGridLine)) {
950 sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
951 }
953 // search for the closest snapped guide line
954 Inkscape::SnappedLine closestGuideLine;
955 if (getClosestSL(sc.guide_lines, closestGuideLine)) {
956 sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
957 }
959 // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
960 // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
962 // When doing a constrained snap however, we're already at an intersection of the constrained line and
963 // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
964 // no need to look for additional intersections
965 if (!constrained) {
966 // search for the closest snapped intersection of grid lines
967 Inkscape::SnappedPoint closestGridPoint;
968 if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
969 closestGridPoint.setSource(p.getSourceType());
970 closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
971 sp_list.push_back(closestGridPoint);
972 }
974 // search for the closest snapped intersection of guide lines
975 Inkscape::SnappedPoint closestGuidePoint;
976 if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
977 closestGuidePoint.setSource(p.getSourceType());
978 closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
979 sp_list.push_back(closestGuidePoint);
980 }
982 // search for the closest snapped intersection of grid with guide lines
983 if (snapprefs.getSnapIntersectionGG()) {
984 Inkscape::SnappedPoint closestGridGuidePoint;
985 if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
986 closestGridGuidePoint.setSource(p.getSourceType());
987 closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
988 sp_list.push_back(closestGridGuidePoint);
989 }
990 }
991 }
993 // now let's see which snapped point gets a thumbs up
994 Inkscape::SnappedPoint bestSnappedPoint(p.getPoint());
995 // std::cout << "Finding the best snap..." << std::endl;
996 for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
997 // std::cout << "sp = " << (*i).getPoint() << " | source = " << (*i).getSource() << " | target = " << (*i).getTarget();
998 bool onScreen = _desktop->get_display_area().contains((*i).getPoint());
999 if (onScreen || allowOffScreen) { // Only snap to points which are not off the screen
1000 if ((*i).getSnapDistance() <= (*i).getTolerance()) { // Only snap to points within snapping range
1001 // if it's the first point, or if it is closer than the best snapped point so far
1002 if (i == sp_list.begin() || bestSnappedPoint.isOtherSnapBetter(*i, false)) {
1003 // then prefer this point over the previous one
1004 bestSnappedPoint = *i;
1005 }
1006 }
1007 }
1008 // std::cout << std::endl;
1009 }
1011 // Update the snap indicator, if requested
1012 if (_snapindicator) {
1013 if (bestSnappedPoint.getSnapped()) {
1014 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
1015 } else {
1016 _desktop->snapindicator->remove_snaptarget();
1017 }
1018 }
1020 // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl;
1021 return bestSnappedPoint;
1022 }
1024 /// Convenience shortcut when there is only one item to ignore
1025 void SnapManager::setup(SPDesktop const *desktop,
1026 bool snapindicator,
1027 SPItem const *item_to_ignore,
1028 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1029 SPGuide *guide_to_ignore)
1030 {
1031 g_assert(desktop != NULL);
1032 _items_to_ignore.clear();
1033 _items_to_ignore.push_back(item_to_ignore);
1034 _desktop = desktop;
1035 _snapindicator = snapindicator;
1036 _unselected_nodes = unselected_nodes;
1037 _guide_to_ignore = guide_to_ignore;
1038 }
1040 /**
1041 * \brief Prepare the snap manager for the actual snapping, which includes building a list of snap targets
1042 * to ignore and toggling the snap indicator
1043 *
1044 * There are two overloaded setup() methods, of which the other one only allows for a single item to be ignored
1045 * whereas this one will take a list of items to ignore
1046 *
1047 * \param desktop Reference to the desktop to which this snap manager is attached
1048 * \param snapindicator If true then a snap indicator will be displayed automatically (when enabled in the preferences)
1049 * \param items_to_ignore These items will not be snapped to, e.g. the items that are currently being dragged. This avoids "self-snapping"
1050 * \param unselected_nodes Stationary nodes of the path that is currently being edited in the node tool and
1051 * that can be snapped too. Nodes not in this list will not be snapped to, to avoid "self-snapping". Of each
1052 * unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored
1053 * \param guide_to_ignore Guide that is currently being dragged and should not be snapped to
1054 */
1056 void SnapManager::setup(SPDesktop const *desktop,
1057 bool snapindicator,
1058 std::vector<SPItem const *> &items_to_ignore,
1059 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1060 SPGuide *guide_to_ignore)
1061 {
1062 g_assert(desktop != NULL);
1063 _items_to_ignore = items_to_ignore;
1064 _desktop = desktop;
1065 _snapindicator = snapindicator;
1066 _unselected_nodes = unselected_nodes;
1067 _guide_to_ignore = guide_to_ignore;
1068 }
1070 /// Setup, taking the list of items to ignore from the desktop's selection.
1071 void SnapManager::setupIgnoreSelection(SPDesktop const *desktop,
1072 bool snapindicator,
1073 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1074 SPGuide *guide_to_ignore)
1075 {
1076 _desktop = desktop;
1077 _snapindicator = snapindicator;
1078 _unselected_nodes = unselected_nodes;
1079 _guide_to_ignore = guide_to_ignore;
1080 _items_to_ignore.clear();
1082 Inkscape::Selection *sel = _desktop->selection;
1083 GSList const *items = sel->itemList();
1084 for (GSList *i = const_cast<GSList*>(items); i; i = i->next) {
1085 _items_to_ignore.push_back(static_cast<SPItem const *>(i->data));
1086 }
1087 }
1089 SPDocument *SnapManager::getDocument() const
1090 {
1091 return _named_view->document;
1092 }
1094 /**
1095 * \brief Takes an untransformed point, applies the given transformation, and returns the transformed point. Eliminates lots of duplicated code
1096 *
1097 * \param p The untransformed position of the point, paired with an identifier of the type of the snap source.
1098 * \param transformation_type Type of transformation to apply.
1099 * \param transformation Mathematical description of the transformation; details depend on the type.
1100 * \param origin Origin of the transformation, if applicable.
1101 * \param dim Dimension to which the transformation applies, if applicable.
1102 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
1103 * \return The position of the point after transformation
1104 */
1106 Geom::Point SnapManager::_transformPoint(Inkscape::SnapCandidatePoint const &p,
1107 Transformation const transformation_type,
1108 Geom::Point const &transformation,
1109 Geom::Point const &origin,
1110 Geom::Dim2 const dim,
1111 bool const uniform) const
1112 {
1113 /* Work out the transformed version of this point */
1114 Geom::Point transformed;
1115 switch (transformation_type) {
1116 case TRANSLATION:
1117 transformed = p.getPoint() + transformation;
1118 break;
1119 case SCALE:
1120 transformed = (p.getPoint() - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
1121 break;
1122 case STRETCH:
1123 {
1124 Geom::Scale s(1, 1);
1125 if (uniform)
1126 s[Geom::X] = s[Geom::Y] = transformation[dim];
1127 else {
1128 s[dim] = transformation[dim];
1129 s[1 - dim] = 1;
1130 }
1131 transformed = ((p.getPoint() - origin) * s) + origin;
1132 break;
1133 }
1134 case SKEW:
1135 // Apply the skew factor
1136 transformed[dim] = (p.getPoint())[dim] + transformation[0] * ((p.getPoint())[1 - dim] - origin[1 - dim]);
1137 // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
1138 // Apply that scale factor here
1139 transformed[1-dim] = (p.getPoint() - origin)[1 - dim] * transformation[1] + origin[1 - dim];
1140 break;
1141 default:
1142 g_assert_not_reached();
1143 }
1145 return transformed;
1146 }
1148 /**
1149 * \brief Mark the location of the snap source (not the snap target!) on the canvas by drawing a symbol
1150 *
1151 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
1152 * \param p The transformed position of the source point, paired with an identifier of the type of the snap source.
1153 */
1155 void SnapManager::_displaySnapsource(Inkscape::SnapCandidatePoint const &p) const {
1157 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
1158 if (prefs->getBool("/options/snapclosestonly/value")) {
1159 bool p_is_a_node = p.getSourceType() & Inkscape::SNAPSOURCE_NODE_CATEGORY;
1160 bool p_is_a_bbox = p.getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY;
1162 if (snapprefs.getSnapEnabledGlobally() && ((p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) {
1163 _desktop->snapindicator->set_new_snapsource(p);
1164 } else {
1165 _desktop->snapindicator->remove_snapsource();
1166 }
1167 }
1168 }
1170 /*
1171 Local Variables:
1172 mode:c++
1173 c-file-style:"stroustrup"
1174 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1175 indent-tabs-mode:nil
1176 fill-column:99
1177 End:
1178 */
1179 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :