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 // 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) {
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>::const_iterator j = transformed_points.begin();
565 // std::cout << std::endl;
566 for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = points.begin(); i != points.end(); i++) {
568 /* Snap it */
569 Inkscape::SnappedPoint snapped_point;
570 Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint;
571 Geom::Point const b = ((*i).getPoint() - origin); // vector to original point
573 if (constrained) {
574 if ((transformation_type == SCALE || transformation_type == STRETCH) && uniform) {
575 // When uniformly scaling, each point will have its own unique constraint line,
576 // running from the scaling origin to the original untransformed point. We will
577 // calculate that line here
578 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, b);
579 } else if (transformation_type == STRETCH) { // when non-uniform stretching {
580 dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i).getPoint(), component_vectors[dim]);
581 } else if (transformation_type == TRANSLATION) {
582 // When doing a constrained translation, all points will move in the same direction, i.e.
583 // either horizontally or vertically. The lines along which they move are therefore all
584 // parallel, but might not be colinear. Therefore we will have to set the point through
585 // which the constraint-line runs here, for each point individually.
586 dedicated_constraint.setPoint((*i).getPoint());
587 } // else: leave the original constraint, e.g. for skewing
588 if (transformation_type == SCALE && !uniform) {
589 g_warning("Non-uniform constrained scaling is not supported!");
590 }
591 snapped_point = constrainedSnap(*j, dedicated_constraint, bbox);
592 } else {
593 bool const c1 = fabs(b[Geom::X]) < 1e-6;
594 bool const c2 = fabs(b[Geom::Y]) < 1e-6;
595 if (transformation_type == SCALE && (c1 || c2) && !(c1 && c2)) {
596 // When scaling, a point aligned either horizontally or vertically with the origin can only
597 // move in that specific direction; therefore it should only snap in that direction, otherwise
598 // we will get snapped points with an invalid transformation
599 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, component_vectors[c1]);
600 snapped_point = constrainedSnap(*j, dedicated_constraint, bbox);
601 } else {
602 snapped_point = freeSnap(*j, bbox);
603 }
604 }
605 // std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl;
606 snapped_point.setPointerDistance(Geom::L2(pointer - (*i).getPoint()));
608 Geom::Point result;
610 if (snapped_point.getSnapped()) {
611 /* We snapped. Find the transformation that describes where the snapped point has
612 ** ended up, and also the metric for this transformation.
613 */
614 Geom::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point
615 //Geom::Point const b = (*i - origin); // vector to original point
617 switch (transformation_type) {
618 case TRANSLATION:
619 result = snapped_point.getPoint() - (*i).getPoint();
620 /* Consider the case in which a box is almost aligned with a grid in both
621 * horizontal and vertical directions. The distance to the intersection of
622 * the grid lines will always be larger then the distance to a single grid
623 * line. If we prefer snapping to an intersection instead of to a single
624 * grid line, then we cannot use "metric = Geom::L2(result)". Therefore the
625 * snapped distance will be used as a metric. Please note that the snapped
626 * distance is defined as the distance to the nearest line of the intersection,
627 * and not to the intersection itself!
628 */
629 // Only for translations, the relevant metric will be the real snapped distance,
630 // so we don't have to do anything special here
631 break;
632 case SCALE:
633 {
634 result = Geom::Point(NR_HUGE, NR_HUGE);
635 // If this point *i is horizontally or vertically aligned with
636 // the origin of the scaling, then it will scale purely in X or Y
637 // We can therefore only calculate the scaling in this direction
638 // and the scaling factor for the other direction should remain
639 // untouched (unless scaling is uniform ofcourse)
640 for (int index = 0; index < 2; index++) {
641 if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
642 if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
643 result[index] = a[index] / b[index]; // then calculate it!
644 }
645 // we might leave result[1-index] = NR_HUGE
646 // if scaling didn't occur in the other direction
647 }
648 }
649 if (uniform) {
650 if (fabs(result[0]) < fabs(result[1])) {
651 result[1] = result[0];
652 } else {
653 result[0] = result[1];
654 }
655 }
656 // Compare the resulting scaling with the desired scaling
657 Geom::Point scale_metric = Geom::abs(result - transformation); // One or both of its components might be NR_HUGE
658 snapped_point.setSnapDistance(std::min(scale_metric[0], scale_metric[1]));
659 snapped_point.setSecondSnapDistance(std::max(scale_metric[0], scale_metric[1]));
660 break;
661 }
662 case STRETCH:
663 result = Geom::Point(NR_HUGE, NR_HUGE);
664 if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
665 result[dim] = a[dim] / b[dim];
666 result[1-dim] = uniform ? result[dim] : 1;
667 } else { // STRETCHING might occur for this point, but only when the stretching is uniform
668 if (uniform && fabs(b[1-dim]) > 1e-6) {
669 result[1-dim] = a[1-dim] / b[1-dim];
670 result[dim] = result[1-dim];
671 }
672 }
673 // Store the metric for this transformation as a virtual distance
674 snapped_point.setSnapDistance(std::abs(result[dim] - transformation[dim]));
675 snapped_point.setSecondSnapDistance(NR_HUGE);
676 break;
677 case SKEW:
678 result[0] = (snapped_point.getPoint()[dim] - ((*i).getPoint())[dim]) / (((*i).getPoint())[1 - dim] - origin[1 - dim]); // skew factor
679 result[1] = transformation[1]; // scale factor
680 // Store the metric for this transformation as a virtual distance
681 snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
682 snapped_point.setSecondSnapDistance(NR_HUGE);
683 break;
684 default:
685 g_assert_not_reached();
686 }
688 // When scaling, we're considering the best transformation in each direction separately. We will have a metric in each
689 // direction, whereas for all other transformation we only a single one-dimensional metric. That's why we need to handle
690 // the scaling metric differently
691 if (best_snapped_point.isOtherSnapBetter(snapped_point, true)) {
692 best_transformation = result;
693 best_snapped_point = snapped_point;
694 }
695 }
697 j++;
698 }
700 Geom::Coord best_metric;
701 if (transformation_type == SCALE) {
702 // When scaling, don't ever exit with one of scaling components set to NR_HUGE
703 for (int index = 0; index < 2; index++) {
704 if (best_transformation[index] == NR_HUGE) {
705 if (uniform && best_transformation[1-index] < NR_HUGE) {
706 best_transformation[index] = best_transformation[1-index];
707 } else {
708 best_transformation[index] = transformation[index];
709 }
710 }
711 }
712 }
714 best_metric = best_snapped_point.getSnapDistance();
715 best_snapped_point.setTransformation(best_transformation);
716 // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
717 // These rounding errors might be caused by NRRects, see bug #1584301
718 best_snapped_point.setSnapDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
719 return best_snapped_point;
720 }
723 /**
724 * \brief Apply a translation to a set of points and try to snap freely in 2 degrees-of-freedom
725 *
726 * \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.
727 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
728 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred
729 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
730 */
732 Inkscape::SnappedPoint SnapManager::freeSnapTranslation(std::vector<Inkscape::SnapCandidatePoint> const &p,
733 Geom::Point const &pointer,
734 Geom::Point const &tr) const
735 {
736 if (p.size() == 1) {
737 Geom::Point pt = _transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
738 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
739 }
741 return _snapTransformed(p, pointer, false, Geom::Point(0,0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
742 }
744 /**
745 * \brief Apply a translation to a set of points and try to snap along a constraint
746 *
747 * \param point_type Category of points to which the source point belongs: node or bounding box.
748 * \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.
749 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
750 * \param constraint The direction or line along which snapping must occur.
751 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred.
752 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
753 */
755 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslation(std::vector<Inkscape::SnapCandidatePoint> const &p,
756 Geom::Point const &pointer,
757 Inkscape::Snapper::ConstraintLine const &constraint,
758 Geom::Point const &tr) const
759 {
760 if (p.size() == 1) {
761 Geom::Point pt = _transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
762 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
763 }
765 return _snapTransformed(p, pointer, true, constraint, TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
766 }
769 /**
770 * \brief Apply a scaling to a set of points and try to snap freely in 2 degrees-of-freedom
771 *
772 * \param point_type Category of points to which the source point belongs: node or bounding box.
773 * \param p Collection of points to snap (snap sources), at their untransformed position, all points undergoing the same transformation. Paired with an identifier of the type of the snap source.
774 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
775 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
776 * \param o Origin of the scaling
777 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
778 */
780 Inkscape::SnappedPoint SnapManager::freeSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
781 Geom::Point const &pointer,
782 Geom::Scale const &s,
783 Geom::Point const &o) const
784 {
785 if (p.size() == 1) {
786 Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
787 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
788 }
790 return _snapTransformed(p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
791 }
794 /**
795 * \brief Apply a scaling to a set of points and snap such that the aspect ratio of the selection is preserved
796 *
797 * \param point_type Category of points to which the source point belongs: node or bounding box.
798 * \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.
799 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
800 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
801 * \param o Origin of the scaling
802 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
803 */
805 Inkscape::SnappedPoint SnapManager::constrainedSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
806 Geom::Point const &pointer,
807 Geom::Scale const &s,
808 Geom::Point const &o) const
809 {
810 // When constrained scaling, only uniform scaling is supported.
811 if (p.size() == 1) {
812 Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
813 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
814 }
816 return _snapTransformed(p, pointer, true, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
817 }
819 /**
820 * \brief Apply a stretch to a set of points and snap such that the direction of the stretch is preserved
821 *
822 * \param point_type Category of points to which the source point belongs: node or bounding box.
823 * \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.
824 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
825 * \param s Proposed stretch; the final stretch can only be calculated after snapping has occurred
826 * \param o Origin of the stretching
827 * \param d Dimension in which to apply proposed stretch.
828 * \param u true if the stretch should be uniform (i.e. to be applied equally in both dimensions)
829 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
830 */
832 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(std::vector<Inkscape::SnapCandidatePoint> const &p,
833 Geom::Point const &pointer,
834 Geom::Coord const &s,
835 Geom::Point const &o,
836 Geom::Dim2 d,
837 bool u) const
838 {
839 if (p.size() == 1) {
840 Geom::Point pt = _transformPoint(p.at(0), STRETCH, Geom::Point(s, s), o, d, u);
841 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
842 }
844 return _snapTransformed(p, pointer, true, Geom::Point(0,0), STRETCH, Geom::Point(s, s), o, d, u);
845 }
847 /**
848 * \brief Apply a skew to a set of points and snap such that the direction of the skew is preserved
849 *
850 * \param point_type Category of points to which the source point belongs: node or bounding box.
851 * \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.
852 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
853 * \param constraint The direction or line along which snapping must occur.
854 * \param s Proposed skew; the final skew can only be calculated after snapping has occurred
855 * \param o Origin of the proposed skew
856 * \param d Dimension in which to apply proposed skew.
857 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
858 */
860 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(std::vector<Inkscape::SnapCandidatePoint> const &p,
861 Geom::Point const &pointer,
862 Inkscape::Snapper::ConstraintLine const &constraint,
863 Geom::Point const &s,
864 Geom::Point const &o,
865 Geom::Dim2 d) const
866 {
867 // "s" contains skew factor in s[0], and scale factor in s[1]
869 // Snapping the nodes of the bounding box of a selection that is being transformed, will only work if
870 // the transformation of the bounding box is equal to the transformation of the individual nodes. This is
871 // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
872 // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
873 // of bounding boxes is not allowed here.
874 if (p.size() > 0) {
875 g_assert(!(p.at(0).getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY));
876 }
878 if (p.size() == 1) {
879 Geom::Point pt = _transformPoint(p.at(0), SKEW, s, o, d, false);
880 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
881 }
883 return _snapTransformed(p, pointer, true, constraint, SKEW, s, o, d, false);
884 }
886 /**
887 * \brief Given a set of possible snap targets, find the best target (which is not necessarily
888 * also the nearest target), and show the snap indicator if requested
889 *
890 * \param p Source point to be snapped
891 * \param sc A structure holding all snap targets that have been found so far
892 * \param constrained True if the snap is constrained, e.g. for stretching or for purely horizontal translation.
893 * \param noCurves If true, then do consider snapping to intersections of curves, but not to the curves themselves
894 * \param allowOffScreen If true, then snapping to points which are off the screen is allowed (needed for example when pasting to the grid)
895 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
896 */
898 Inkscape::SnappedPoint SnapManager::findBestSnap(Inkscape::SnapCandidatePoint const &p,
899 SnappedConstraints const &sc,
900 bool constrained,
901 bool noCurves,
902 bool allowOffScreen) const
903 {
905 /*
906 std::cout << "Type and number of snapped constraints: " << std::endl;
907 std::cout << " Points : " << sc.points.size() << std::endl;
908 std::cout << " Lines : " << sc.lines.size() << std::endl;
909 std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
910 std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
911 std::cout << " Curves : " << sc.curves.size()<< std::endl;
912 */
914 // Store all snappoints
915 std::list<Inkscape::SnappedPoint> sp_list;
917 // search for the closest snapped point
918 Inkscape::SnappedPoint closestPoint;
919 if (getClosestSP(sc.points, closestPoint)) {
920 sp_list.push_back(closestPoint);
921 }
923 // search for the closest snapped curve
924 if (!noCurves) {
925 Inkscape::SnappedCurve closestCurve;
926 if (getClosestCurve(sc.curves, closestCurve)) {
927 sp_list.push_back(Inkscape::SnappedPoint(closestCurve));
928 }
929 }
931 if (snapprefs.getSnapIntersectionCS()) {
932 // search for the closest snapped intersection of curves
933 Inkscape::SnappedPoint closestCurvesIntersection;
934 if (getClosestIntersectionCS(sc.curves, p.getPoint(), closestCurvesIntersection, _desktop->dt2doc())) {
935 closestCurvesIntersection.setSource(p.getSourceType());
936 sp_list.push_back(closestCurvesIntersection);
937 }
938 }
940 // search for the closest snapped grid line
941 Inkscape::SnappedLine closestGridLine;
942 if (getClosestSL(sc.grid_lines, closestGridLine)) {
943 sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
944 }
946 // search for the closest snapped guide line
947 Inkscape::SnappedLine closestGuideLine;
948 if (getClosestSL(sc.guide_lines, closestGuideLine)) {
949 sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
950 }
952 // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
953 // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
955 // When doing a constrained snap however, we're already at an intersection of the constrained line and
956 // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
957 // no need to look for additional intersections
958 if (!constrained) {
959 // search for the closest snapped intersection of grid lines
960 Inkscape::SnappedPoint closestGridPoint;
961 if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
962 closestGridPoint.setSource(p.getSourceType());
963 closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
964 sp_list.push_back(closestGridPoint);
965 }
967 // search for the closest snapped intersection of guide lines
968 Inkscape::SnappedPoint closestGuidePoint;
969 if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
970 closestGuidePoint.setSource(p.getSourceType());
971 closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
972 sp_list.push_back(closestGuidePoint);
973 }
975 // search for the closest snapped intersection of grid with guide lines
976 if (snapprefs.getSnapIntersectionGG()) {
977 Inkscape::SnappedPoint closestGridGuidePoint;
978 if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
979 closestGridGuidePoint.setSource(p.getSourceType());
980 closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
981 sp_list.push_back(closestGridGuidePoint);
982 }
983 }
984 }
986 // now let's see which snapped point gets a thumbs up
987 Inkscape::SnappedPoint bestSnappedPoint(p.getPoint());
988 // std::cout << "Finding the best snap..." << std::endl;
989 for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
990 // std::cout << "sp = " << (*i).getPoint() << " | source = " << (*i).getSource() << " | target = " << (*i).getTarget();
991 bool onScreen = _desktop->get_display_area().contains((*i).getPoint());
992 if (onScreen || allowOffScreen) { // Only snap to points which are not off the screen
993 if ((*i).getSnapDistance() <= (*i).getTolerance()) { // Only snap to points within snapping range
994 // if it's the first point, or if it is closer than the best snapped point so far
995 if (i == sp_list.begin() || bestSnappedPoint.isOtherSnapBetter(*i, false)) {
996 // then prefer this point over the previous one
997 bestSnappedPoint = *i;
998 }
999 }
1000 }
1001 // std::cout << std::endl;
1002 }
1004 // Update the snap indicator, if requested
1005 if (_snapindicator) {
1006 if (bestSnappedPoint.getSnapped()) {
1007 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
1008 } else {
1009 _desktop->snapindicator->remove_snaptarget();
1010 }
1011 }
1013 // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl;
1014 return bestSnappedPoint;
1015 }
1017 /// Convenience shortcut when there is only one item to ignore
1018 void SnapManager::setup(SPDesktop const *desktop,
1019 bool snapindicator,
1020 SPItem const *item_to_ignore,
1021 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1022 SPGuide *guide_to_ignore)
1023 {
1024 g_assert(desktop != NULL);
1025 _items_to_ignore.clear();
1026 _items_to_ignore.push_back(item_to_ignore);
1027 _desktop = desktop;
1028 _snapindicator = snapindicator;
1029 _unselected_nodes = unselected_nodes;
1030 _guide_to_ignore = guide_to_ignore;
1031 }
1033 /**
1034 * \brief Prepare the snap manager for the actual snapping, which includes building a list of snap targets
1035 * to ignore and toggling the snap indicator
1036 *
1037 * There are two overloaded setup() methods, of which the other one only allows for a single item to be ignored
1038 * whereas this one will take a list of items to ignore
1039 *
1040 * \param desktop Reference to the desktop to which this snap manager is attached
1041 * \param snapindicator If true then a snap indicator will be displayed automatically (when enabled in the preferences)
1042 * \param items_to_ignore These items will not be snapped to, e.g. the items that are currently being dragged. This avoids "self-snapping"
1043 * \param unselected_nodes Stationary nodes of the path that is currently being edited in the node tool and
1044 * that can be snapped too. Nodes not in this list will not be snapped to, to avoid "self-snapping". Of each
1045 * unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored
1046 * \param guide_to_ignore Guide that is currently being dragged and should not be snapped to
1047 */
1049 void SnapManager::setup(SPDesktop const *desktop,
1050 bool snapindicator,
1051 std::vector<SPItem const *> &items_to_ignore,
1052 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1053 SPGuide *guide_to_ignore)
1054 {
1055 g_assert(desktop != NULL);
1056 _items_to_ignore = items_to_ignore;
1057 _desktop = desktop;
1058 _snapindicator = snapindicator;
1059 _unselected_nodes = unselected_nodes;
1060 _guide_to_ignore = guide_to_ignore;
1061 }
1063 /// Setup, taking the list of items to ignore from the desktop's selection.
1064 void SnapManager::setupIgnoreSelection(SPDesktop const *desktop,
1065 bool snapindicator,
1066 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1067 SPGuide *guide_to_ignore)
1068 {
1069 _desktop = desktop;
1070 _snapindicator = snapindicator;
1071 _unselected_nodes = unselected_nodes;
1072 _guide_to_ignore = guide_to_ignore;
1073 _items_to_ignore.clear();
1075 Inkscape::Selection *sel = _desktop->selection;
1076 GSList const *items = sel->itemList();
1077 for (GSList *i = const_cast<GSList*>(items); i; i = i->next) {
1078 _items_to_ignore.push_back(static_cast<SPItem const *>(i->data));
1079 }
1080 }
1082 SPDocument *SnapManager::getDocument() const
1083 {
1084 return _named_view->document;
1085 }
1087 /**
1088 * \brief Takes an untransformed point, applies the given transformation, and returns the transformed point. Eliminates lots of duplicated code
1089 *
1090 * \param p The untransformed position of the point, paired with an identifier of the type of the snap source.
1091 * \param transformation_type Type of transformation to apply.
1092 * \param transformation Mathematical description of the transformation; details depend on the type.
1093 * \param origin Origin of the transformation, if applicable.
1094 * \param dim Dimension to which the transformation applies, if applicable.
1095 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
1096 * \return The position of the point after transformation
1097 */
1099 Geom::Point SnapManager::_transformPoint(Inkscape::SnapCandidatePoint const &p,
1100 Transformation const transformation_type,
1101 Geom::Point const &transformation,
1102 Geom::Point const &origin,
1103 Geom::Dim2 const dim,
1104 bool const uniform) const
1105 {
1106 /* Work out the transformed version of this point */
1107 Geom::Point transformed;
1108 switch (transformation_type) {
1109 case TRANSLATION:
1110 transformed = p.getPoint() + transformation;
1111 break;
1112 case SCALE:
1113 transformed = (p.getPoint() - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
1114 break;
1115 case STRETCH:
1116 {
1117 Geom::Scale s(1, 1);
1118 if (uniform)
1119 s[Geom::X] = s[Geom::Y] = transformation[dim];
1120 else {
1121 s[dim] = transformation[dim];
1122 s[1 - dim] = 1;
1123 }
1124 transformed = ((p.getPoint() - origin) * s) + origin;
1125 break;
1126 }
1127 case SKEW:
1128 // Apply the skew factor
1129 transformed[dim] = (p.getPoint())[dim] + transformation[0] * ((p.getPoint())[1 - dim] - origin[1 - dim]);
1130 // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
1131 // Apply that scale factor here
1132 transformed[1-dim] = (p.getPoint() - origin)[1 - dim] * transformation[1] + origin[1 - dim];
1133 break;
1134 default:
1135 g_assert_not_reached();
1136 }
1138 return transformed;
1139 }
1141 /**
1142 * \brief Mark the location of the snap source (not the snap target!) on the canvas by drawing a symbol
1143 *
1144 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
1145 * \param p The transformed position of the source point, paired with an identifier of the type of the snap source.
1146 */
1148 void SnapManager::_displaySnapsource(Inkscape::SnapCandidatePoint const &p) const {
1150 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
1151 if (prefs->getBool("/options/snapclosestonly/value")) {
1152 bool p_is_a_node = p.getSourceType() & Inkscape::SNAPSOURCE_NODE_CATEGORY;
1153 bool p_is_a_bbox = p.getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY;
1155 if (snapprefs.getSnapEnabledGlobally() && ((p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) {
1156 _desktop->snapindicator->set_new_snapsource(p);
1157 } else {
1158 _desktop->snapindicator->remove_snapsource();
1159 }
1160 }
1161 }
1163 /*
1164 Local Variables:
1165 mode:c++
1166 c-file-style:"stroustrup"
1167 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1168 indent-tabs-mode:nil
1169 fill-column:99
1170 End:
1171 */
1172 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :