1 #define __SP_DESKTOP_SNAP_C__
3 /**
4 * \file snap.cpp
5 * \brief SnapManager class.
6 *
7 * Authors:
8 * Lauris Kaplinski <lauris@kaplinski.com>
9 * Frank Felfe <innerspace@iname.com>
10 * Nathan Hurst <njh@njhurst.com>
11 * Carl Hetherington <inkscape@carlh.net>
12 * Diederik van Lierop <mail@diedenrezi.nl>
13 *
14 * Copyright (C) 2006-2007 Johan Engelen <johan@shouraizou.nl>
15 * Copyrigth (C) 2004 Nathan Hurst
16 * Copyright (C) 1999-2010 Authors
17 *
18 * Released under GNU GPL, read the file 'COPYING' for more information
19 */
21 #include <utility>
23 #include "sp-namedview.h"
24 #include "snap.h"
25 #include "snapped-line.h"
26 #include "snapped-curve.h"
28 #include "display/canvas-grid.h"
29 #include "display/snap-indicator.h"
31 #include "inkscape.h"
32 #include "desktop.h"
33 #include "selection.h"
34 #include "sp-guide.h"
35 #include "preferences.h"
36 #include "event-context.h"
37 using std::vector;
39 /**
40 * Construct a SnapManager for a SPNamedView.
41 *
42 * \param v `Owning' SPNamedView.
43 */
45 SnapManager::SnapManager(SPNamedView const *v) :
46 guide(this, 0),
47 object(this, 0),
48 snapprefs(),
49 _named_view(v)
50 {
51 }
53 /**
54 * \brief Return a list of snappers
55 *
56 * Inkscape snaps to objects, grids, and guides. For each of these snap targets a
57 * separate class is used, which has been derived from the base Snapper class. The
58 * getSnappers() method returns a list of pointers to instances of this class. This
59 * list contains exactly one instance of the guide snapper and of the object snapper
60 * class, but any number of grid snappers (because each grid has its own snapper
61 * instance)
62 *
63 * \return List of snappers that we use.
64 */
65 SnapManager::SnapperList
66 SnapManager::getSnappers() const
67 {
68 SnapManager::SnapperList s;
69 s.push_back(&guide);
70 s.push_back(&object);
72 SnapManager::SnapperList gs = getGridSnappers();
73 s.splice(s.begin(), gs);
75 return s;
76 }
78 /**
79 * \brief Return a list of gridsnappers
80 *
81 * Each grid has its own instance of the snapper class. This way snapping can
82 * be enabled per grid individually. A list will be returned containing the
83 * pointers to these instances, but only for grids that are being displayed
84 * and for which snapping is enabled.
85 *
86 * \return List of gridsnappers that we use.
87 */
88 SnapManager::SnapperList
89 SnapManager::getGridSnappers() const
90 {
91 SnapperList s;
93 if (_desktop && _desktop->gridsEnabled() && snapprefs.getSnapToGrids()) {
94 for ( GSList const *l = _named_view->grids; l != NULL; l = l->next) {
95 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
96 s.push_back(grid->snapper);
97 }
98 }
100 return s;
101 }
103 /**
104 * \brief Return true if any snapping might occur, whether its to grids, guides or objects
105 *
106 * Each snapper instance handles its own snapping target, e.g. grids, guides or
107 * objects. This method iterates through all these snapper instances and returns
108 * true if any of the snappers might possible snap, considering only the relevant
109 * snapping preferences.
110 *
111 * \return true if one of the snappers will try to snap to something.
112 */
114 bool SnapManager::someSnapperMightSnap() const
115 {
116 if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) {
117 return false;
118 }
120 SnapperList const s = getSnappers();
121 SnapperList::const_iterator i = s.begin();
122 while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
123 i++;
124 }
126 return (i != s.end());
127 }
129 /**
130 * \return true if one of the grids might be snapped to.
131 */
133 bool SnapManager::gridSnapperMightSnap() const
134 {
135 if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) {
136 return false;
137 }
139 SnapperList const s = getGridSnappers();
140 SnapperList::const_iterator i = s.begin();
141 while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
142 i++;
143 }
145 return (i != s.end());
146 }
148 /**
149 * \brief Try to snap a point to grids, guides or objects.
150 *
151 * Try to snap a point to grids, guides or objects, in two degrees-of-freedom,
152 * i.e. snap in any direction on the two dimensional canvas to the nearest
153 * snap target. freeSnapReturnByRef() is equal in snapping behavior to
154 * freeSnap(), but the former returns the snapped point trough the referenced
155 * parameter p. This parameter p initially contains the position of the snap
156 * source and will we overwritten by the target position if snapping has occurred.
157 * This makes snapping transparent to the calling code. If this is not desired
158 * because either the calling code must know whether snapping has occurred, or
159 * because the original position should not be touched, then freeSnap() should be
160 * called instead.
161 *
162 * PS:
163 * 1) SnapManager::setup() must have been called before calling this method,
164 * but only once for a set of points
165 * 2) Only to be used when a single source point is to be snapped; it assumes
166 * that source_num = 0, which is inefficient when snapping sets our source points
167 *
168 * \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred
169 * \param source_type Detailed description of the source type, will be used by the snap indicator
170 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
171 */
173 void SnapManager::freeSnapReturnByRef(Geom::Point &p,
174 Inkscape::SnapSourceType const source_type,
175 Geom::OptRect const &bbox_to_snap) const
176 {
177 //TODO: SnapCandidatePoint and point_type are somewhat redundant; can't we get rid of the point_type parameter?
178 Inkscape::SnappedPoint const s = freeSnap(Inkscape::SnapCandidatePoint(p, source_type), bbox_to_snap);
179 s.getPoint(p);
180 }
183 /**
184 * \brief Try to snap a point to grids, guides or objects.
185 *
186 * Try to snap a point to grids, guides or objects, in two degrees-of-freedom,
187 * i.e. snap in any direction on the two dimensional canvas to the nearest
188 * snap target. freeSnap() is equal in snapping behavior to
189 * freeSnapReturnByRef(). Please read the comments of the latter for more details
190 *
191 * PS: SnapManager::setup() must have been called before calling this method,
192 * but only once for a set of points
193 *
194 * \param p Source point to be snapped
195 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
196 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
197 */
200 Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::SnapCandidatePoint const &p,
201 Geom::OptRect const &bbox_to_snap) const
202 {
203 if (!someSnapperMightSnap()) {
204 return Inkscape::SnappedPoint(p, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false, false);
205 }
207 SnappedConstraints sc;
208 SnapperList const snappers = getSnappers();
210 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
211 (*i)->freeSnap(sc, p, bbox_to_snap, &_items_to_ignore, _unselected_nodes);
212 }
214 return findBestSnap(p, sc, false);
215 }
217 void SnapManager::preSnap(Inkscape::SnapCandidatePoint const &p)
218 {
219 // setup() must have been called before calling this method!
221 if (_snapindicator) {
222 _snapindicator = false; // prevent other methods from drawing a snap indicator; we want to control this here
223 Inkscape::SnappedPoint s = freeSnap(p);
224 if (s.getSnapped()) {
225 _desktop->snapindicator->set_new_snaptarget(s, true);
226 } else {
227 _desktop->snapindicator->remove_snaptarget(true);
228 }
229 _snapindicator = true; // restore the original value
230 }
231 }
233 /**
234 * \brief Snap to the closest multiple of a grid pitch
235 *
236 * When pasting, we would like to snap to the grid. Problem is that we don't know which
237 * nodes were aligned to the grid at the time of copying, so we don't know which nodes
238 * to snap. If we'd snap an unaligned node to the grid, previously aligned nodes would
239 * become unaligned. That's undesirable. Instead we will make sure that the offset
240 * between the source and its pasted copy is a multiple of the grid pitch. If the source
241 * was aligned, then the copy will therefore also be aligned.
242 *
243 * PS: Whether we really find a multiple also depends on the snapping range! Most users
244 * will have "always snap" enabled though, in which case a multiple will always be found.
245 * PS2: When multiple grids are present then the result will become ambiguous. There is no
246 * way to control to which grid this method will snap.
247 *
248 * \param t Vector that represents the offset of the pasted copy with respect to the original
249 * \return Offset vector after snapping to the closest multiple of a grid pitch
250 */
252 Geom::Point SnapManager::multipleOfGridPitch(Geom::Point const &t, Geom::Point const &origin)
253 {
254 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally())
255 return t;
257 if (_desktop && _desktop->gridsEnabled()) {
258 bool success = false;
259 Geom::Point nearest_multiple;
260 Geom::Coord nearest_distance = NR_HUGE;
261 Inkscape::SnappedPoint bestSnappedPoint(t);
263 // It will snap to the grid for which we find the closest snap. This might be a different
264 // grid than to which the objects were initially aligned. I don't see an easy way to fix
265 // this, so when using multiple grids one can get unexpected results
267 // Cannot use getGridSnappers() because we need both the grids AND their snappers
268 // Therefore we iterate through all grids manually
269 for (GSList const *l = _named_view->grids; l != NULL; l = l->next) {
270 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
271 const Inkscape::Snapper* snapper = grid->snapper;
272 if (snapper && snapper->ThisSnapperMightSnap()) {
273 // To find the nearest multiple of the grid pitch for a given translation t, we
274 // will use the grid snapper. Simply snapping the value t to the grid will do, but
275 // only if the origin of the grid is at (0,0). If it's not then compensate for this
276 // in the translation t
277 Geom::Point const t_offset = t + grid->origin;
278 SnappedConstraints sc;
279 // Only the first three parameters are being used for grid snappers
280 snapper->freeSnap(sc, Inkscape::SnapCandidatePoint(t_offset, Inkscape::SNAPSOURCE_GRID_PITCH),Geom::OptRect(), NULL, NULL);
281 // Find the best snap for this grid, including intersections of the grid-lines
282 bool old_val = _snapindicator;
283 _snapindicator = false;
284 Inkscape::SnappedPoint s = findBestSnap(Inkscape::SnapCandidatePoint(t_offset, Inkscape::SNAPSOURCE_GRID_PITCH), sc, false, false, true);
285 _snapindicator = old_val;
286 if (s.getSnapped() && (s.getSnapDistance() < nearest_distance)) {
287 // use getSnapDistance() instead of getWeightedDistance() here because the pointer's position
288 // doesn't tell us anything about which node to snap
289 success = true;
290 nearest_multiple = s.getPoint() - to_2geom(grid->origin);
291 nearest_distance = s.getSnapDistance();
292 bestSnappedPoint = s;
293 }
294 }
295 }
297 if (success) {
298 bestSnappedPoint.setPoint(origin + nearest_multiple);
299 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
300 return nearest_multiple;
301 }
302 }
304 return t;
305 }
307 /**
308 * \brief Try to snap a point along a constraint line to grids, guides or objects.
309 *
310 * Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
311 * i.e. snap in a specific direction on the two dimensional canvas to the nearest
312 * snap target.
313 *
314 * constrainedSnapReturnByRef() is equal in snapping behavior to
315 * constrainedSnap(), but the former returns the snapped point trough the referenced
316 * parameter p. This parameter p initially contains the position of the snap
317 * source and will we overwritten by the target position if snapping has occurred.
318 * This makes snapping transparent to the calling code. If this is not desired
319 * because either the calling code must know whether snapping has occurred, or
320 * because the original position should not be touched, then constrainedSnap() should
321 * be called instead.
322 *
323 * PS:
324 * 1) SnapManager::setup() must have been called before calling this method,
325 * but only once for a set of points
326 * 2) Only to be used when a single source point is to be snapped; it assumes
327 * that source_num = 0, which is inefficient when snapping sets our source points
329 *
330 * \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred
331 * \param source_type Detailed description of the source type, will be used by the snap indicator
332 * \param constraint The direction or line along which snapping must occur
333 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
334 */
336 void SnapManager::constrainedSnapReturnByRef(Geom::Point &p,
337 Inkscape::SnapSourceType const source_type,
338 Inkscape::Snapper::ConstraintLine const &constraint,
339 Geom::OptRect const &bbox_to_snap) const
340 {
341 Inkscape::SnappedPoint const s = constrainedSnap(Inkscape::SnapCandidatePoint(p, source_type, 0), constraint, bbox_to_snap);
342 s.getPoint(p);
343 }
345 /**
346 * \brief Try to snap a point along a constraint line to grids, guides or objects.
347 *
348 * Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
349 * i.e. snap in a specific direction on the two dimensional canvas to the nearest
350 * snap target. constrainedSnap is equal in snapping behavior to
351 * constrainedSnapReturnByRef(). Please read the comments of the latter for more details.
352 *
353 * PS: SnapManager::setup() must have been called before calling this method,
354 * but only once for a set of points
355 *
356 * \param p Source point to be snapped
357 * \param constraint The direction or line along which snapping must occur
358 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
359 */
361 Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::SnapCandidatePoint const &p,
362 Inkscape::Snapper::ConstraintLine const &constraint,
363 Geom::OptRect const &bbox_to_snap) const
364 {
365 // First project the mouse pointer onto the constraint
366 Geom::Point pp = constraint.projection(p.getPoint());
368 Inkscape::SnappedPoint no_snap = Inkscape::SnappedPoint(pp, p.getSourceType(), p.getSourceNum(), Inkscape::SNAPTARGET_CONSTRAINT, Geom::L2(pp - p.getPoint()), 0, false, true, false);
370 if (!someSnapperMightSnap()) {
371 // Always return point on constraint
372 return no_snap;
373 }
375 SnappedConstraints sc;
376 SnapperList const snappers = getSnappers();
377 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
378 (*i)->constrainedSnap(sc, p, bbox_to_snap, constraint, &_items_to_ignore);
379 }
381 Inkscape::SnappedPoint result = findBestSnap(p, sc, true);
383 if (result.getSnapped()) {
384 // only change the snap indicator if we really snapped to something
385 if (_snapindicator) {
386 _desktop->snapindicator->set_new_snaptarget(result);
387 }
388 return result;
389 }
390 return no_snap;
391 }
393 /**
394 * \brief Try to snap a point of a guide to another guide or to a node
395 *
396 * Try to snap a point of a guide to another guide or to a node in two degrees-
397 * of-freedom, i.e. snap in any direction on the two dimensional canvas to the
398 * nearest snap target. This method is used when dragging or rotating a guide
399 *
400 * PS: SnapManager::setup() must have been called before calling this method,
401 *
402 * \param p Current position of the point on the guide that is to be snapped; will be overwritten by the position of the snap target if snapping has occurred
403 * \param guide_normal Vector normal to the guide line
404 */
405 void SnapManager::guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const
406 {
407 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
408 return;
409 }
411 if (!(object.GuidesMightSnap() || snapprefs.getSnapToGuides())) {
412 return;
413 }
415 Inkscape::SnapCandidatePoint candidate(p, Inkscape::SNAPSOURCE_GUIDE_ORIGIN);
416 if (drag_type == SP_DRAG_ROTATE) {
417 candidate = Inkscape::SnapCandidatePoint(p, Inkscape::SNAPSOURCE_GUIDE);
418 }
420 // Snap to nodes
421 SnappedConstraints sc;
422 if (object.GuidesMightSnap()) {
423 object.guideFreeSnap(sc, p, guide_normal);
424 }
426 // Snap to guides & grid lines
427 SnapperList snappers = getGridSnappers();
428 snappers.push_back(&guide);
429 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
430 (*i)->freeSnap(sc, candidate, Geom::OptRect(), NULL, NULL);
431 }
433 Inkscape::SnappedPoint const s = findBestSnap(candidate, sc, false, false);
435 s.getPoint(p);
436 }
438 /**
439 * \brief Try to snap a point on a guide to the intersection with another guide or a path
440 *
441 * Try to snap a point on a guide to the intersection of that guide with another
442 * guide or with a path. The snapped point will lie somewhere on the guide-line,
443 * making this is a constrained snap, i.e. in only one degree-of-freedom.
444 * This method is used when dragging the origin of the guide along the guide itself.
445 *
446 * PS: SnapManager::setup() must have been called before calling this method,
447 *
448 * \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
449 * \param guide_normal Vector normal to the guide line
450 */
452 void SnapManager::guideConstrainedSnap(Geom::Point &p, SPGuide const &guideline) const
453 {
454 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
455 return;
456 }
458 if (!(object.ThisSnapperMightSnap() || snapprefs.getSnapToGuides())) {
459 return;
460 }
462 Inkscape::SnapCandidatePoint candidate(p, Inkscape::SNAPSOURCE_GUIDE_ORIGIN, Inkscape::SNAPTARGET_UNDEFINED);
464 // Snap to nodes or paths
465 SnappedConstraints sc;
466 Inkscape::Snapper::ConstraintLine cl(guideline.point_on_line, Geom::rot90(guideline.normal_to_line));
467 if (object.ThisSnapperMightSnap()) {
468 object.constrainedSnap(sc, candidate, Geom::OptRect(), cl, NULL);
469 }
471 // Snap to guides & grid lines
472 SnapperList snappers = getGridSnappers();
473 snappers.push_back(&guide);
474 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
475 (*i)->constrainedSnap(sc, candidate, Geom::OptRect(), cl, NULL);
476 }
478 Inkscape::SnappedPoint const s = findBestSnap(candidate, sc, false);
479 s.getPoint(p);
480 }
482 /**
483 * \brief Method for snapping sets of points while they are being transformed
484 *
485 * Method for snapping sets of points while they are being transformed, when using
486 * for example the selector tool. This method is for internal use only, and should
487 * not have to be called directly. Use freeSnapTransalation(), constrainedSnapScale(),
488 * etc. instead.
489 *
490 * This is what is being done in this method: transform each point, find out whether
491 * a free snap or constrained snap is more appropriate, do the snapping, calculate
492 * some metrics to quantify the snap "distance", and see if it's better than the
493 * previous snap. Finally, the best ("nearest") snap from all these points is returned.
494 *
495 * \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.
496 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
497 * \param constrained true if the snap is constrained, e.g. for stretching or for purely horizontal translation.
498 * \param constraint The direction or line along which snapping must occur, if 'constrained' is true; otherwise undefined.
499 * \param transformation_type Type of transformation to apply to points before trying to snap them.
500 * \param transformation Description of the transformation; details depend on the type.
501 * \param origin Origin of the transformation, if applicable.
502 * \param dim Dimension to which the transformation applies, if applicable.
503 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
504 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
505 */
507 Inkscape::SnappedPoint SnapManager::_snapTransformed(
508 std::vector<Inkscape::SnapCandidatePoint> const &points,
509 Geom::Point const &pointer,
510 bool constrained,
511 Inkscape::Snapper::ConstraintLine const &constraint,
512 Transformation transformation_type,
513 Geom::Point const &transformation,
514 Geom::Point const &origin,
515 Geom::Dim2 dim,
516 bool uniform) const
517 {
518 /* We have a list of points, which we are proposing to transform in some way. We need to see
519 ** if any of these points, when transformed, snap to anything. If they do, we return the
520 ** appropriate transformation with `true'; otherwise we return the original scale with `false'.
521 */
523 /* Quick check to see if we have any snappers that are enabled
524 ** Also used to globally disable all snapping
525 */
526 if (someSnapperMightSnap() == false || points.size() == 0) {
527 return Inkscape::SnappedPoint(pointer);
528 }
530 std::vector<Inkscape::SnapCandidatePoint> transformed_points;
531 Geom::Rect bbox;
533 long source_num = 0;
534 for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = points.begin(); i != points.end(); i++) {
536 /* Work out the transformed version of this point */
537 Geom::Point transformed = _transformPoint(*i, transformation_type, transformation, origin, dim, uniform);
539 // add the current transformed point to the box hulling all transformed points
540 if (i == points.begin()) {
541 bbox = Geom::Rect(transformed, transformed);
542 } else {
543 bbox.expandTo(transformed);
544 }
546 transformed_points.push_back(Inkscape::SnapCandidatePoint(transformed, (*i).getSourceType(), source_num));
547 source_num++;
548 }
550 /* The current best transformation */
551 Geom::Point best_transformation = transformation;
553 /* The current best metric for the best transformation; lower is better, NR_HUGE
554 ** means that we haven't snapped anything.
555 */
556 Geom::Point best_scale_metric(NR_HUGE, NR_HUGE);
557 Inkscape::SnappedPoint best_snapped_point;
558 g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point
559 g_assert(best_snapped_point.getAtIntersection() == false);
561 std::vector<Inkscape::SnapCandidatePoint>::iterator j = transformed_points.begin();
564 // std::cout << std::endl;
565 bool first_free_snap = true;
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 // If we have a collection of SnapCandidatePoints, with mixed constrained snapping and free snapping
603 // requirements, then freeSnap might never see the SnapCandidatePoint with source_num == 0. The freeSnap()
604 // method in the object snapper depends on this, because only for source-num == 0 the target nodes will
605 // be collected. Therefore we enforce that the first SnapCandidatePoint that is to be freeSnapped always
606 // has source_num == 0;
607 // TODO: This is a bit ugly so fix this; do we need sourcenum for anything else? if we don't then get rid
608 // of it and explicitely communicate to the object snapper that this is a first point
609 if (first_free_snap) {
610 (*j).setSourceNum(0);
611 first_free_snap = false;
612 }
613 snapped_point = freeSnap(*j, bbox);
614 }
615 }
616 // std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl;
617 snapped_point.setPointerDistance(Geom::L2(pointer - (*i).getPoint()));
619 Geom::Point result;
621 if (snapped_point.getSnapped()) {
622 /* We snapped. Find the transformation that describes where the snapped point has
623 ** ended up, and also the metric for this transformation.
624 */
625 Geom::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point
626 //Geom::Point const b = (*i - origin); // vector to original point
628 switch (transformation_type) {
629 case TRANSLATION:
630 result = snapped_point.getPoint() - (*i).getPoint();
631 /* Consider the case in which a box is almost aligned with a grid in both
632 * horizontal and vertical directions. The distance to the intersection of
633 * the grid lines will always be larger then the distance to a single grid
634 * line. If we prefer snapping to an intersection instead of to a single
635 * grid line, then we cannot use "metric = Geom::L2(result)". Therefore the
636 * snapped distance will be used as a metric. Please note that the snapped
637 * distance is defined as the distance to the nearest line of the intersection,
638 * and not to the intersection itself!
639 */
640 // Only for translations, the relevant metric will be the real snapped distance,
641 // so we don't have to do anything special here
642 break;
643 case SCALE:
644 {
645 result = Geom::Point(NR_HUGE, NR_HUGE);
646 // If this point *i is horizontally or vertically aligned with
647 // the origin of the scaling, then it will scale purely in X or Y
648 // We can therefore only calculate the scaling in this direction
649 // and the scaling factor for the other direction should remain
650 // untouched (unless scaling is uniform of course)
651 for (int index = 0; index < 2; index++) {
652 if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
653 if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
654 result[index] = a[index] / b[index]; // then calculate it!
655 }
656 // we might leave result[1-index] = NR_HUGE
657 // if scaling didn't occur in the other direction
658 }
659 }
660 if (uniform) {
661 if (fabs(result[0]) < fabs(result[1])) {
662 result[1] = result[0];
663 } else {
664 result[0] = result[1];
665 }
666 }
667 // Compare the resulting scaling with the desired scaling
668 Geom::Point scale_metric = Geom::abs(result - transformation); // One or both of its components might be NR_HUGE
669 snapped_point.setSnapDistance(std::min(scale_metric[0], scale_metric[1]));
670 snapped_point.setSecondSnapDistance(std::max(scale_metric[0], scale_metric[1]));
671 break;
672 }
673 case STRETCH:
674 result = Geom::Point(NR_HUGE, NR_HUGE);
675 if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
676 result[dim] = a[dim] / b[dim];
677 result[1-dim] = uniform ? result[dim] : 1;
678 } else { // STRETCHING might occur for this point, but only when the stretching is uniform
679 if (uniform && fabs(b[1-dim]) > 1e-6) {
680 result[1-dim] = a[1-dim] / b[1-dim];
681 result[dim] = result[1-dim];
682 }
683 }
684 // Store the metric for this transformation as a virtual distance
685 snapped_point.setSnapDistance(std::abs(result[dim] - transformation[dim]));
686 snapped_point.setSecondSnapDistance(NR_HUGE);
687 break;
688 case SKEW:
689 result[0] = (snapped_point.getPoint()[dim] - ((*i).getPoint())[dim]) / (((*i).getPoint())[1 - dim] - origin[1 - dim]); // skew factor
690 result[1] = transformation[1]; // scale factor
691 // Store the metric for this transformation as a virtual distance
692 snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
693 snapped_point.setSecondSnapDistance(NR_HUGE);
694 break;
695 default:
696 g_assert_not_reached();
697 }
699 if (best_snapped_point.isOtherSnapBetter(snapped_point, true)) {
700 best_transformation = result;
701 best_snapped_point = snapped_point;
702 }
703 }
705 j++;
706 }
708 Geom::Coord best_metric;
709 if (transformation_type == SCALE) {
710 // When scaling, don't ever exit with one of scaling components set to NR_HUGE
711 for (int index = 0; index < 2; index++) {
712 if (best_transformation[index] == NR_HUGE) {
713 if (uniform && best_transformation[1-index] < NR_HUGE) {
714 best_transformation[index] = best_transformation[1-index];
715 } else {
716 best_transformation[index] = transformation[index];
717 }
718 }
719 }
720 }
722 best_metric = best_snapped_point.getSnapDistance();
723 best_snapped_point.setTransformation(best_transformation);
724 // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
725 // These rounding errors might be caused by NRRects, see bug #1584301
726 best_snapped_point.setSnapDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
727 return best_snapped_point;
728 }
731 /**
732 * \brief Apply a translation to a set of points and try to snap freely in 2 degrees-of-freedom
733 *
734 * \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.
735 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
736 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred
737 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
738 */
740 Inkscape::SnappedPoint SnapManager::freeSnapTranslation(std::vector<Inkscape::SnapCandidatePoint> const &p,
741 Geom::Point const &pointer,
742 Geom::Point const &tr) const
743 {
744 if (p.size() == 1) {
745 Geom::Point pt = _transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
746 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
747 }
749 return _snapTransformed(p, pointer, false, Geom::Point(0,0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
750 }
752 /**
753 * \brief Apply a translation to a set of points and try to snap along a constraint
754 *
755 * \param point_type Category of points to which the source point belongs: node or bounding box.
756 * \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.
757 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
758 * \param constraint The direction or line along which snapping must occur.
759 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred.
760 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
761 */
763 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslation(std::vector<Inkscape::SnapCandidatePoint> const &p,
764 Geom::Point const &pointer,
765 Inkscape::Snapper::ConstraintLine const &constraint,
766 Geom::Point const &tr) const
767 {
768 if (p.size() == 1) {
769 Geom::Point pt = _transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
770 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
771 }
773 return _snapTransformed(p, pointer, true, constraint, TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
774 }
777 /**
778 * \brief Apply a scaling to a set of points and try to snap freely in 2 degrees-of-freedom
779 *
780 * \param point_type Category of points to which the source point belongs: node or bounding box.
781 * \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.
782 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
783 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
784 * \param o Origin of the scaling
785 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
786 */
788 Inkscape::SnappedPoint SnapManager::freeSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
789 Geom::Point const &pointer,
790 Geom::Scale const &s,
791 Geom::Point const &o) const
792 {
793 if (p.size() == 1) {
794 Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
795 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
796 }
798 return _snapTransformed(p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
799 }
802 /**
803 * \brief Apply a scaling to a set of points and snap such that the aspect ratio of the selection is preserved
804 *
805 * \param point_type Category of points to which the source point belongs: node or bounding box.
806 * \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.
807 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
808 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
809 * \param o Origin of the scaling
810 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
811 */
813 Inkscape::SnappedPoint SnapManager::constrainedSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
814 Geom::Point const &pointer,
815 Geom::Scale const &s,
816 Geom::Point const &o) const
817 {
818 // When constrained scaling, only uniform scaling is supported.
819 if (p.size() == 1) {
820 Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
821 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
822 }
824 return _snapTransformed(p, pointer, true, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
825 }
827 /**
828 * \brief Apply a stretch to a set of points and snap such that the direction of the stretch is preserved
829 *
830 * \param point_type Category of points to which the source point belongs: node or bounding box.
831 * \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.
832 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
833 * \param s Proposed stretch; the final stretch can only be calculated after snapping has occurred
834 * \param o Origin of the stretching
835 * \param d Dimension in which to apply proposed stretch.
836 * \param u true if the stretch should be uniform (i.e. to be applied equally in both dimensions)
837 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
838 */
840 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(std::vector<Inkscape::SnapCandidatePoint> const &p,
841 Geom::Point const &pointer,
842 Geom::Coord const &s,
843 Geom::Point const &o,
844 Geom::Dim2 d,
845 bool u) const
846 {
847 if (p.size() == 1) {
848 Geom::Point pt = _transformPoint(p.at(0), STRETCH, Geom::Point(s, s), o, d, u);
849 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
850 }
852 return _snapTransformed(p, pointer, true, Geom::Point(0,0), STRETCH, Geom::Point(s, s), o, d, u);
853 }
855 /**
856 * \brief Apply a skew to a set of points and snap such that the direction of the skew is preserved
857 *
858 * \param point_type Category of points to which the source point belongs: node or bounding box.
859 * \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.
860 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
861 * \param constraint The direction or line along which snapping must occur.
862 * \param s Proposed skew; the final skew can only be calculated after snapping has occurred
863 * \param o Origin of the proposed skew
864 * \param d Dimension in which to apply proposed skew.
865 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
866 */
868 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(std::vector<Inkscape::SnapCandidatePoint> const &p,
869 Geom::Point const &pointer,
870 Inkscape::Snapper::ConstraintLine const &constraint,
871 Geom::Point const &s,
872 Geom::Point const &o,
873 Geom::Dim2 d) const
874 {
875 // "s" contains skew factor in s[0], and scale factor in s[1]
877 // Snapping the nodes of the bounding box of a selection that is being transformed, will only work if
878 // the transformation of the bounding box is equal to the transformation of the individual nodes. This is
879 // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
880 // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
881 // of bounding boxes is not allowed here.
882 if (p.size() > 0) {
883 g_assert(!(p.at(0).getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY));
884 }
886 if (p.size() == 1) {
887 Geom::Point pt = _transformPoint(p.at(0), SKEW, s, o, d, false);
888 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
889 }
891 return _snapTransformed(p, pointer, true, constraint, SKEW, s, o, d, false);
892 }
894 /**
895 * \brief Given a set of possible snap targets, find the best target (which is not necessarily
896 * also the nearest target), and show the snap indicator if requested
897 *
898 * \param p Source point to be snapped
899 * \param sc A structure holding all snap targets that have been found so far
900 * \param constrained True if the snap is constrained, e.g. for stretching or for purely horizontal translation.
901 * \param noCurves If true, then do consider snapping to intersections of curves, but not to the curves themselves
902 * \param allowOffScreen If true, then snapping to points which are off the screen is allowed (needed for example when pasting to the grid)
903 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
904 */
906 Inkscape::SnappedPoint SnapManager::findBestSnap(Inkscape::SnapCandidatePoint const &p,
907 SnappedConstraints const &sc,
908 bool constrained,
909 bool noCurves,
910 bool allowOffScreen) const
911 {
914 /*
915 std::cout << "Type and number of snapped constraints: " << std::endl;
916 std::cout << " Points : " << sc.points.size() << std::endl;
917 std::cout << " Lines : " << sc.lines.size() << std::endl;
918 std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
919 std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
920 std::cout << " Curves : " << sc.curves.size()<< std::endl;
921 */
923 // Store all snappoints
924 std::list<Inkscape::SnappedPoint> sp_list;
926 // search for the closest snapped point
927 Inkscape::SnappedPoint closestPoint;
928 if (getClosestSP(sc.points, closestPoint)) {
929 sp_list.push_back(closestPoint);
930 }
932 // search for the closest snapped curve
933 if (!noCurves) {
934 Inkscape::SnappedCurve closestCurve;
935 if (getClosestCurve(sc.curves, closestCurve)) {
936 sp_list.push_back(Inkscape::SnappedPoint(closestCurve));
937 }
938 }
940 if (snapprefs.getSnapIntersectionCS()) {
941 // search for the closest snapped intersection of curves
942 Inkscape::SnappedPoint closestCurvesIntersection;
943 if (getClosestIntersectionCS(sc.curves, p.getPoint(), closestCurvesIntersection, _desktop->dt2doc())) {
944 closestCurvesIntersection.setSource(p.getSourceType());
945 sp_list.push_back(closestCurvesIntersection);
946 }
947 }
949 // search for the closest snapped grid line
950 Inkscape::SnappedLine closestGridLine;
951 if (getClosestSL(sc.grid_lines, closestGridLine)) {
952 sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
953 }
955 // search for the closest snapped guide line
956 Inkscape::SnappedLine closestGuideLine;
957 if (getClosestSL(sc.guide_lines, closestGuideLine)) {
958 sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
959 }
961 // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
962 // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
964 // When doing a constrained snap however, we're already at an intersection of the constrained line and
965 // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
966 // no need to look for additional intersections
967 if (!constrained) {
968 // search for the closest snapped intersection of grid lines
969 Inkscape::SnappedPoint closestGridPoint;
970 if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
971 closestGridPoint.setSource(p.getSourceType());
972 closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
973 sp_list.push_back(closestGridPoint);
974 }
976 // search for the closest snapped intersection of guide lines
977 Inkscape::SnappedPoint closestGuidePoint;
978 if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
979 closestGuidePoint.setSource(p.getSourceType());
980 closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
981 sp_list.push_back(closestGuidePoint);
982 }
984 // search for the closest snapped intersection of grid with guide lines
985 if (snapprefs.getSnapIntersectionGG()) {
986 Inkscape::SnappedPoint closestGridGuidePoint;
987 if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
988 closestGridGuidePoint.setSource(p.getSourceType());
989 closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
990 sp_list.push_back(closestGridGuidePoint);
991 }
992 }
993 }
995 // now let's see which snapped point gets a thumbs up
996 Inkscape::SnappedPoint bestSnappedPoint(p.getPoint());
997 // std::cout << "Finding the best snap..." << std::endl;
998 for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
999 // std::cout << "sp = " << (*i).getPoint() << " | source = " << (*i).getSource() << " | target = " << (*i).getTarget();
1000 bool onScreen = _desktop->get_display_area().contains((*i).getPoint());
1001 if (onScreen || allowOffScreen) { // Only snap to points which are not off the screen
1002 if ((*i).getSnapDistance() <= (*i).getTolerance()) { // Only snap to points within snapping range
1003 // if it's the first point, or if it is closer than the best snapped point so far
1004 if (i == sp_list.begin() || bestSnappedPoint.isOtherSnapBetter(*i, false)) {
1005 // then prefer this point over the previous one
1006 bestSnappedPoint = *i;
1007 }
1008 }
1009 }
1010 // std::cout << std::endl;
1011 }
1013 // Update the snap indicator, if requested
1014 if (_snapindicator) {
1015 if (bestSnappedPoint.getSnapped()) {
1016 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
1017 } else {
1018 _desktop->snapindicator->remove_snaptarget();
1019 }
1020 }
1022 // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl;
1023 return bestSnappedPoint;
1024 }
1026 /// Convenience shortcut when there is only one item to ignore
1027 void SnapManager::setup(SPDesktop const *desktop,
1028 bool snapindicator,
1029 SPItem const *item_to_ignore,
1030 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1031 SPGuide *guide_to_ignore)
1032 {
1033 g_assert(desktop != NULL);
1034 _items_to_ignore.clear();
1035 _items_to_ignore.push_back(item_to_ignore);
1036 _desktop = desktop;
1037 _snapindicator = snapindicator;
1038 _unselected_nodes = unselected_nodes;
1039 _guide_to_ignore = guide_to_ignore;
1040 }
1042 /**
1043 * \brief Prepare the snap manager for the actual snapping, which includes building a list of snap targets
1044 * to ignore and toggling the snap indicator
1045 *
1046 * There are two overloaded setup() methods, of which the other one only allows for a single item to be ignored
1047 * whereas this one will take a list of items to ignore
1048 *
1049 * \param desktop Reference to the desktop to which this snap manager is attached
1050 * \param snapindicator If true then a snap indicator will be displayed automatically (when enabled in the preferences)
1051 * \param items_to_ignore These items will not be snapped to, e.g. the items that are currently being dragged. This avoids "self-snapping"
1052 * \param unselected_nodes Stationary nodes of the path that is currently being edited in the node tool and
1053 * that can be snapped too. Nodes not in this list will not be snapped to, to avoid "self-snapping". Of each
1054 * unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored
1055 * \param guide_to_ignore Guide that is currently being dragged and should not be snapped to
1056 */
1058 void SnapManager::setup(SPDesktop const *desktop,
1059 bool snapindicator,
1060 std::vector<SPItem const *> &items_to_ignore,
1061 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1062 SPGuide *guide_to_ignore)
1063 {
1064 g_assert(desktop != NULL);
1065 _items_to_ignore = items_to_ignore;
1066 _desktop = desktop;
1067 _snapindicator = snapindicator;
1068 _unselected_nodes = unselected_nodes;
1069 _guide_to_ignore = guide_to_ignore;
1070 }
1072 /// Setup, taking the list of items to ignore from the desktop's selection.
1073 void SnapManager::setupIgnoreSelection(SPDesktop const *desktop,
1074 bool snapindicator,
1075 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1076 SPGuide *guide_to_ignore)
1077 {
1078 _desktop = desktop;
1079 _snapindicator = snapindicator;
1080 _unselected_nodes = unselected_nodes;
1081 _guide_to_ignore = guide_to_ignore;
1082 _items_to_ignore.clear();
1084 Inkscape::Selection *sel = _desktop->selection;
1085 GSList const *items = sel->itemList();
1086 for (GSList *i = const_cast<GSList*>(items); i; i = i->next) {
1087 _items_to_ignore.push_back(static_cast<SPItem const *>(i->data));
1088 }
1089 }
1091 SPDocument *SnapManager::getDocument() const
1092 {
1093 return _named_view->document;
1094 }
1096 /**
1097 * \brief Takes an untransformed point, applies the given transformation, and returns the transformed point. Eliminates lots of duplicated code
1098 *
1099 * \param p The untransformed position of the point, paired with an identifier of the type of the snap source.
1100 * \param transformation_type Type of transformation to apply.
1101 * \param transformation Mathematical description of the transformation; details depend on the type.
1102 * \param origin Origin of the transformation, if applicable.
1103 * \param dim Dimension to which the transformation applies, if applicable.
1104 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
1105 * \return The position of the point after transformation
1106 */
1108 Geom::Point SnapManager::_transformPoint(Inkscape::SnapCandidatePoint const &p,
1109 Transformation const transformation_type,
1110 Geom::Point const &transformation,
1111 Geom::Point const &origin,
1112 Geom::Dim2 const dim,
1113 bool const uniform) const
1114 {
1115 /* Work out the transformed version of this point */
1116 Geom::Point transformed;
1117 switch (transformation_type) {
1118 case TRANSLATION:
1119 transformed = p.getPoint() + transformation;
1120 break;
1121 case SCALE:
1122 transformed = (p.getPoint() - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
1123 break;
1124 case STRETCH:
1125 {
1126 Geom::Scale s(1, 1);
1127 if (uniform)
1128 s[Geom::X] = s[Geom::Y] = transformation[dim];
1129 else {
1130 s[dim] = transformation[dim];
1131 s[1 - dim] = 1;
1132 }
1133 transformed = ((p.getPoint() - origin) * s) + origin;
1134 break;
1135 }
1136 case SKEW:
1137 // Apply the skew factor
1138 transformed[dim] = (p.getPoint())[dim] + transformation[0] * ((p.getPoint())[1 - dim] - origin[1 - dim]);
1139 // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
1140 // Apply that scale factor here
1141 transformed[1-dim] = (p.getPoint() - origin)[1 - dim] * transformation[1] + origin[1 - dim];
1142 break;
1143 default:
1144 g_assert_not_reached();
1145 }
1147 return transformed;
1148 }
1150 /**
1151 * \brief Mark the location of the snap source (not the snap target!) on the canvas by drawing a symbol
1152 *
1153 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
1154 * \param p The transformed position of the source point, paired with an identifier of the type of the snap source.
1155 */
1157 void SnapManager::_displaySnapsource(Inkscape::SnapCandidatePoint const &p) const {
1159 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
1160 if (prefs->getBool("/options/snapclosestonly/value")) {
1161 bool p_is_a_node = p.getSourceType() & Inkscape::SNAPSOURCE_NODE_CATEGORY;
1162 bool p_is_a_bbox = p.getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY;
1164 if (snapprefs.getSnapEnabledGlobally() && ((p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) {
1165 _desktop->snapindicator->set_new_snapsource(p);
1166 } else {
1167 _desktop->snapindicator->remove_snapsource();
1168 }
1169 }
1170 }
1172 /*
1173 Local Variables:
1174 mode:c++
1175 c-file-style:"stroustrup"
1176 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1177 indent-tabs-mode:nil
1178 fill-column:99
1179 End:
1180 */
1181 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :