53832994f386c2a616bdaee75dd86478b61bb3ad
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) const
253 {
254 if (!snapprefs.getSnapEnabledGlobally()) // No need to check for snapprefs.getSnapPostponedGlobally() here
255 return t;
257 if (_desktop && _desktop->gridsEnabled()) {
258 bool success = false;
259 Geom::Point nearest_multiple;
260 Geom::Coord nearest_distance = NR_HUGE;
262 // It will snap to the grid for which we find the closest snap. This might be a different
263 // grid than to which the objects were initially aligned. I don't see an easy way to fix
264 // this, so when using multiple grids one can get unexpected results
266 // Cannot use getGridSnappers() because we need both the grids AND their snappers
267 // Therefore we iterate through all grids manually
268 for (GSList const *l = _named_view->grids; l != NULL; l = l->next) {
269 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
270 const Inkscape::Snapper* snapper = grid->snapper;
271 if (snapper && snapper->ThisSnapperMightSnap()) {
272 // To find the nearest multiple of the grid pitch for a given translation t, we
273 // will use the grid snapper. Simply snapping the value t to the grid will do, but
274 // only if the origin of the grid is at (0,0). If it's not then compensate for this
275 // in the translation t
276 Geom::Point const t_offset = t + grid->origin;
277 SnappedConstraints sc;
278 // Only the first three parameters are being used for grid snappers
279 snapper->freeSnap(sc, Inkscape::SnapCandidatePoint(t_offset, Inkscape::SNAPSOURCE_UNDEFINED),Geom::OptRect(), NULL, NULL);
280 // Find the best snap for this grid, including intersections of the grid-lines
281 Inkscape::SnappedPoint s = findBestSnap(Inkscape::SnapCandidatePoint(t_offset, Inkscape::SNAPSOURCE_UNDEFINED), sc, false);
282 if (s.getSnapped() && (s.getSnapDistance() < nearest_distance)) {
283 // use getSnapDistance() instead of getWeightedDistance() here because the pointer's position
284 // doesn't tell us anything about which node to snap
285 success = true;
286 nearest_multiple = s.getPoint() - to_2geom(grid->origin);
287 nearest_distance = s.getSnapDistance();
288 }
289 }
290 }
292 if (success)
293 return nearest_multiple;
294 }
296 return t;
297 }
299 /**
300 * \brief Try to snap a point along a constraint line to grids, guides or objects.
301 *
302 * Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
303 * i.e. snap in a specific direction on the two dimensional canvas to the nearest
304 * snap target.
305 *
306 * constrainedSnapReturnByRef() is equal in snapping behavior to
307 * constrainedSnap(), but the former returns the snapped point trough the referenced
308 * parameter p. This parameter p initially contains the position of the snap
309 * source and will we overwritten by the target position if snapping has occurred.
310 * This makes snapping transparent to the calling code. If this is not desired
311 * because either the calling code must know whether snapping has occurred, or
312 * because the original position should not be touched, then constrainedSnap() should
313 * be called instead.
314 *
315 * PS:
316 * 1) SnapManager::setup() must have been called before calling this method,
317 * but only once for a set of points
318 * 2) Only to be used when a single source point is to be snapped; it assumes
319 * that source_num = 0, which is inefficient when snapping sets our source points
321 *
322 * \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred
323 * \param source_type Detailed description of the source type, will be used by the snap indicator
324 * \param constraint The direction or line along which snapping must occur
325 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
326 */
328 void SnapManager::constrainedSnapReturnByRef(Geom::Point &p,
329 Inkscape::SnapSourceType const source_type,
330 Inkscape::Snapper::ConstraintLine const &constraint,
331 Geom::OptRect const &bbox_to_snap) const
332 {
333 Inkscape::SnappedPoint const s = constrainedSnap(Inkscape::SnapCandidatePoint(p, source_type, 0), constraint, bbox_to_snap);
334 s.getPoint(p);
335 }
337 /**
338 * \brief Try to snap a point along a constraint line to grids, guides or objects.
339 *
340 * Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
341 * i.e. snap in a specific direction on the two dimensional canvas to the nearest
342 * snap target. constrainedSnap is equal in snapping behavior to
343 * constrainedSnapReturnByRef(). Please read the comments of the latter for more details.
344 *
345 * PS: SnapManager::setup() must have been called before calling this method,
346 * but only once for a set of points
347 *
348 * \param p Source point to be snapped
349 * \param constraint The direction or line along which snapping must occur
350 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
351 */
353 Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::SnapCandidatePoint const &p,
354 Inkscape::Snapper::ConstraintLine const &constraint,
355 Geom::OptRect const &bbox_to_snap) const
356 {
357 // First project the mouse pointer onto the constraint
358 Geom::Point pp = constraint.projection(p.getPoint());
360 Inkscape::SnappedPoint no_snap = Inkscape::SnappedPoint(pp, p.getSourceType(), p.getSourceNum(), Inkscape::SNAPTARGET_CONSTRAINT, Geom::L2(pp - p.getPoint()), 0, false, false);
362 if (!someSnapperMightSnap()) {
363 // The constraint should always be enforced, so we return pp here instead of p
364 if (_snapindicator) {
365 _desktop->snapindicator->set_new_snaptarget(no_snap);
366 }
367 return no_snap;
368 }
370 // Then try to snap the projected point
371 Inkscape::SnapCandidatePoint candidate(pp, p.getSourceType(), p.getSourceNum(), Inkscape::SNAPTARGET_UNDEFINED, Geom::Rect());
373 SnappedConstraints sc;
374 SnapperList const snappers = getSnappers();
375 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
376 (*i)->constrainedSnap(sc, candidate, bbox_to_snap, constraint, &_items_to_ignore);
377 }
379 Inkscape::SnappedPoint result = findBestSnap(candidate, sc, true);
381 if (result.getSnapped()) {
382 return result;
383 }
385 // The constraint should always be enforced, so we return pp here instead of p
386 if (_snapindicator) {
387 _desktop->snapindicator->set_new_snaptarget(no_snap);
388 }
389 return no_snap;
390 }
392 /**
393 * \brief Try to snap a point of a guide to another guide or to a node
394 *
395 * Try to snap a point of a guide to another guide or to a node in two degrees-
396 * of-freedom, i.e. snap in any direction on the two dimensional canvas to the
397 * nearest snap target. This method is used when dragging or rotating a guide
398 *
399 * PS: SnapManager::setup() must have been called before calling this method,
400 *
401 * \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
402 * \param guide_normal Vector normal to the guide line
403 */
404 void SnapManager::guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const
405 {
406 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
407 return;
408 }
410 if (!(object.GuidesMightSnap() || snapprefs.getSnapToGuides())) {
411 return;
412 }
414 Inkscape::SnapCandidatePoint candidate(p, Inkscape::SNAPSOURCE_GUIDE_ORIGIN);
415 if (drag_type == SP_DRAG_ROTATE) {
416 candidate = Inkscape::SnapCandidatePoint(p, Inkscape::SNAPSOURCE_GUIDE);
417 }
419 // Snap to nodes
420 SnappedConstraints sc;
421 if (object.GuidesMightSnap()) {
422 object.guideFreeSnap(sc, p, guide_normal);
423 }
425 // Snap to guides & grid lines
426 SnapperList snappers = getGridSnappers();
427 snappers.push_back(&guide);
428 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
429 (*i)->freeSnap(sc, candidate, Geom::OptRect(), NULL, NULL);
430 }
432 // Snap to intersections of curves, but not to the curves themselves! (see _snapTranslatingGuideToNodes in object-snapper.cpp)
433 Inkscape::SnappedPoint const s = findBestSnap(candidate, sc, false, true);
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) {
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>::const_iterator j = transformed_points.begin();
564 // std::cout << std::endl;
565 for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = points.begin(); i != points.end(); i++) {
567 /* Snap it */
568 Inkscape::SnappedPoint snapped_point;
569 Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint;
570 Geom::Point const b = ((*i).getPoint() - origin); // vector to original point
572 if (constrained) {
573 if ((transformation_type == SCALE || transformation_type == STRETCH) && uniform) {
574 // When uniformly scaling, each point will have its own unique constraint line,
575 // running from the scaling origin to the original untransformed point. We will
576 // calculate that line here
577 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, b);
578 } else if (transformation_type == STRETCH) { // when non-uniform stretching {
579 dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i).getPoint(), component_vectors[dim]);
580 } else if (transformation_type == TRANSLATION) {
581 // When doing a constrained translation, all points will move in the same direction, i.e.
582 // either horizontally or vertically. The lines along which they move are therefore all
583 // parallel, but might not be colinear. Therefore we will have to set the point through
584 // which the constraint-line runs here, for each point individually.
585 dedicated_constraint.setPoint((*i).getPoint());
586 } // else: leave the original constraint, e.g. for skewing
587 if (transformation_type == SCALE && !uniform) {
588 g_warning("Non-uniform constrained scaling is not supported!");
589 }
590 snapped_point = constrainedSnap(*j, dedicated_constraint, bbox);
591 } else {
592 bool const c1 = fabs(b[Geom::X]) < 1e-6;
593 bool const c2 = fabs(b[Geom::Y]) < 1e-6;
594 if (transformation_type == SCALE && (c1 || c2) && !(c1 && c2)) {
595 // When scaling, a point aligned either horizontally or vertically with the origin can only
596 // move in that specific direction; therefore it should only snap in that direction, otherwise
597 // we will get snapped points with an invalid transformation
598 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, component_vectors[c1]);
599 snapped_point = constrainedSnap(*j, dedicated_constraint, bbox);
600 } else {
601 snapped_point = freeSnap(*j, bbox);
602 }
603 }
604 // std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl;
605 snapped_point.setPointerDistance(Geom::L2(pointer - (*i).getPoint()));
607 Geom::Point result;
609 if (snapped_point.getSnapped()) {
610 /* We snapped. Find the transformation that describes where the snapped point has
611 ** ended up, and also the metric for this transformation.
612 */
613 Geom::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point
614 //Geom::Point const b = (*i - origin); // vector to original point
616 switch (transformation_type) {
617 case TRANSLATION:
618 result = snapped_point.getPoint() - (*i).getPoint();
619 /* Consider the case in which a box is almost aligned with a grid in both
620 * horizontal and vertical directions. The distance to the intersection of
621 * the grid lines will always be larger then the distance to a single grid
622 * line. If we prefer snapping to an intersection instead of to a single
623 * grid line, then we cannot use "metric = Geom::L2(result)". Therefore the
624 * snapped distance will be used as a metric. Please note that the snapped
625 * distance is defined as the distance to the nearest line of the intersection,
626 * and not to the intersection itself!
627 */
628 // Only for translations, the relevant metric will be the real snapped distance,
629 // so we don't have to do anything special here
630 break;
631 case SCALE:
632 {
633 result = Geom::Point(NR_HUGE, NR_HUGE);
634 // If this point *i is horizontally or vertically aligned with
635 // the origin of the scaling, then it will scale purely in X or Y
636 // We can therefore only calculate the scaling in this direction
637 // and the scaling factor for the other direction should remain
638 // untouched (unless scaling is uniform ofcourse)
639 for (int index = 0; index < 2; index++) {
640 if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
641 if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
642 result[index] = a[index] / b[index]; // then calculate it!
643 }
644 // we might leave result[1-index] = NR_HUGE
645 // if scaling didn't occur in the other direction
646 }
647 }
648 if (uniform) {
649 if (fabs(result[0]) < fabs(result[1])) {
650 result[1] = result[0];
651 } else {
652 result[0] = result[1];
653 }
654 }
655 // Compare the resulting scaling with the desired scaling
656 Geom::Point scale_metric = Geom::abs(result - transformation); // One or both of its components might be NR_HUGE
657 snapped_point.setSnapDistance(std::min(scale_metric[0], scale_metric[1]));
658 snapped_point.setSecondSnapDistance(std::max(scale_metric[0], scale_metric[1]));
659 break;
660 }
661 case STRETCH:
662 result = Geom::Point(NR_HUGE, NR_HUGE);
663 if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
664 result[dim] = a[dim] / b[dim];
665 result[1-dim] = uniform ? result[dim] : 1;
666 } else { // STRETCHING might occur for this point, but only when the stretching is uniform
667 if (uniform && fabs(b[1-dim]) > 1e-6) {
668 result[1-dim] = a[1-dim] / b[1-dim];
669 result[dim] = result[1-dim];
670 }
671 }
672 // Store the metric for this transformation as a virtual distance
673 snapped_point.setSnapDistance(std::abs(result[dim] - transformation[dim]));
674 snapped_point.setSecondSnapDistance(NR_HUGE);
675 break;
676 case SKEW:
677 result[0] = (snapped_point.getPoint()[dim] - ((*i).getPoint())[dim]) / (((*i).getPoint())[1 - dim] - origin[1 - dim]); // skew factor
678 result[1] = transformation[1]; // scale factor
679 // Store the metric for this transformation as a virtual distance
680 snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
681 snapped_point.setSecondSnapDistance(NR_HUGE);
682 break;
683 default:
684 g_assert_not_reached();
685 }
687 // When scaling, we're considering the best transformation in each direction separately. We will have a metric in each
688 // direction, whereas for all other transformation we only a single one-dimensional metric. That's why we need to handle
689 // the scaling metric differently
690 if (best_snapped_point.isOtherSnapBetter(snapped_point, true)) {
691 best_transformation = result;
692 best_snapped_point = snapped_point;
693 }
694 }
696 j++;
697 }
699 Geom::Coord best_metric;
700 if (transformation_type == SCALE) {
701 // When scaling, don't ever exit with one of scaling components set to NR_HUGE
702 for (int index = 0; index < 2; index++) {
703 if (best_transformation[index] == NR_HUGE) {
704 if (uniform && best_transformation[1-index] < NR_HUGE) {
705 best_transformation[index] = best_transformation[1-index];
706 } else {
707 best_transformation[index] = transformation[index];
708 }
709 }
710 }
711 }
713 best_metric = best_snapped_point.getSnapDistance();
714 best_snapped_point.setTransformation(best_transformation);
715 // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
716 // These rounding errors might be caused by NRRects, see bug #1584301
717 best_snapped_point.setSnapDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
718 return best_snapped_point;
719 }
722 /**
723 * \brief Apply a translation to a set of points and try to snap freely in 2 degrees-of-freedom
724 *
725 * \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.
726 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
727 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred
728 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
729 */
731 Inkscape::SnappedPoint SnapManager::freeSnapTranslation(std::vector<Inkscape::SnapCandidatePoint> const &p,
732 Geom::Point const &pointer,
733 Geom::Point const &tr) const
734 {
735 if (p.size() == 1) {
736 Geom::Point pt = _transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
737 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
738 }
740 return _snapTransformed(p, pointer, false, Geom::Point(0,0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
741 }
743 /**
744 * \brief Apply a translation to a set of points and try to snap along a constraint
745 *
746 * \param point_type Category of points to which the source point belongs: node or bounding box.
747 * \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.
748 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
749 * \param constraint The direction or line along which snapping must occur.
750 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred.
751 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
752 */
754 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslation(std::vector<Inkscape::SnapCandidatePoint> const &p,
755 Geom::Point const &pointer,
756 Inkscape::Snapper::ConstraintLine const &constraint,
757 Geom::Point const &tr) const
758 {
759 if (p.size() == 1) {
760 Geom::Point pt = _transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
761 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
762 }
764 return _snapTransformed(p, pointer, true, constraint, TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
765 }
768 /**
769 * \brief Apply a scaling to a set of points and try to snap freely in 2 degrees-of-freedom
770 *
771 * \param point_type Category of points to which the source point belongs: node or bounding box.
772 * \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.
773 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
774 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
775 * \param o Origin of the scaling
776 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
777 */
779 Inkscape::SnappedPoint SnapManager::freeSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
780 Geom::Point const &pointer,
781 Geom::Scale const &s,
782 Geom::Point const &o) const
783 {
784 if (p.size() == 1) {
785 Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
786 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
787 }
789 return _snapTransformed(p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
790 }
793 /**
794 * \brief Apply a scaling to a set of points and snap such that the aspect ratio of the selection is preserved
795 *
796 * \param point_type Category of points to which the source point belongs: node or bounding box.
797 * \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.
798 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
799 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
800 * \param o Origin of the scaling
801 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
802 */
804 Inkscape::SnappedPoint SnapManager::constrainedSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p,
805 Geom::Point const &pointer,
806 Geom::Scale const &s,
807 Geom::Point const &o) const
808 {
809 // When constrained scaling, only uniform scaling is supported.
810 if (p.size() == 1) {
811 Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
812 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
813 }
815 return _snapTransformed(p, pointer, true, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
816 }
818 /**
819 * \brief Apply a stretch to a set of points and snap such that the direction of the stretch is preserved
820 *
821 * \param point_type Category of points to which the source point belongs: node or bounding box.
822 * \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.
823 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
824 * \param s Proposed stretch; the final stretch can only be calculated after snapping has occurred
825 * \param o Origin of the stretching
826 * \param d Dimension in which to apply proposed stretch.
827 * \param u true if the stretch should be uniform (i.e. to be applied equally in both dimensions)
828 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
829 */
831 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(std::vector<Inkscape::SnapCandidatePoint> const &p,
832 Geom::Point const &pointer,
833 Geom::Coord const &s,
834 Geom::Point const &o,
835 Geom::Dim2 d,
836 bool u) const
837 {
838 if (p.size() == 1) {
839 Geom::Point pt = _transformPoint(p.at(0), STRETCH, Geom::Point(s, s), o, d, u);
840 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
841 }
843 return _snapTransformed(p, pointer, true, Geom::Point(0,0), STRETCH, Geom::Point(s, s), o, d, u);
844 }
846 /**
847 * \brief Apply a skew to a set of points and snap such that the direction of the skew is preserved
848 *
849 * \param point_type Category of points to which the source point belongs: node or bounding box.
850 * \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.
851 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
852 * \param constraint The direction or line along which snapping must occur.
853 * \param s Proposed skew; the final skew can only be calculated after snapping has occurred
854 * \param o Origin of the proposed skew
855 * \param d Dimension in which to apply proposed skew.
856 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
857 */
859 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(std::vector<Inkscape::SnapCandidatePoint> const &p,
860 Geom::Point const &pointer,
861 Inkscape::Snapper::ConstraintLine const &constraint,
862 Geom::Point const &s,
863 Geom::Point const &o,
864 Geom::Dim2 d) const
865 {
866 // "s" contains skew factor in s[0], and scale factor in s[1]
868 // Snapping the nodes of the bounding box of a selection that is being transformed, will only work if
869 // the transformation of the bounding box is equal to the transformation of the individual nodes. This is
870 // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
871 // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
872 // of bounding boxes is not allowed here.
873 if (p.size() > 0) {
874 g_assert(!(p.at(0).getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY));
875 }
877 if (p.size() == 1) {
878 Geom::Point pt = _transformPoint(p.at(0), SKEW, s, o, d, false);
879 _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType()));
880 }
882 return _snapTransformed(p, pointer, true, constraint, SKEW, s, o, d, false);
883 }
885 /**
886 * \brief Given a set of possible snap targets, find the best target (which is not necessarily
887 * also the nearest target), and show the snap indicator if requested
888 *
889 * \param p Source point to be snapped
890 * \param sc A structure holding all snap targets that have been found so far
891 * \param constrained True if the snap is constrained, e.g. for stretching or for purely horizontal translation.
892 * \param noCurves If true, then do consider snapping to intersections of curves, but not to the curves themselves
893 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
894 */
896 Inkscape::SnappedPoint SnapManager::findBestSnap(Inkscape::SnapCandidatePoint const &p,
897 SnappedConstraints const &sc,
898 bool constrained,
899 bool noCurves) const
900 {
902 /*
903 std::cout << "Type and number of snapped constraints: " << std::endl;
904 std::cout << " Points : " << sc.points.size() << std::endl;
905 std::cout << " Lines : " << sc.lines.size() << std::endl;
906 std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
907 std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
908 std::cout << " Curves : " << sc.curves.size()<< std::endl;
909 */
911 // Store all snappoints
912 std::list<Inkscape::SnappedPoint> sp_list;
914 // search for the closest snapped point
915 Inkscape::SnappedPoint closestPoint;
916 if (getClosestSP(sc.points, closestPoint)) {
917 sp_list.push_back(closestPoint);
918 }
920 // search for the closest snapped curve
921 if (!noCurves) {
922 Inkscape::SnappedCurve closestCurve;
923 if (getClosestCurve(sc.curves, closestCurve)) {
924 sp_list.push_back(Inkscape::SnappedPoint(closestCurve));
925 }
926 }
928 if (snapprefs.getSnapIntersectionCS()) {
929 // search for the closest snapped intersection of curves
930 Inkscape::SnappedPoint closestCurvesIntersection;
931 if (getClosestIntersectionCS(sc.curves, p.getPoint(), closestCurvesIntersection, _desktop->dt2doc())) {
932 closestCurvesIntersection.setSource(p.getSourceType());
933 sp_list.push_back(closestCurvesIntersection);
934 }
935 }
937 // search for the closest snapped grid line
938 Inkscape::SnappedLine closestGridLine;
939 if (getClosestSL(sc.grid_lines, closestGridLine)) {
940 sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
941 }
943 // search for the closest snapped guide line
944 Inkscape::SnappedLine closestGuideLine;
945 if (getClosestSL(sc.guide_lines, closestGuideLine)) {
946 sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
947 }
949 // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
950 // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
952 // When doing a constrained snap however, we're already at an intersection of the constrained line and
953 // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
954 // no need to look for additional intersections
955 if (!constrained) {
956 // search for the closest snapped intersection of grid lines
957 Inkscape::SnappedPoint closestGridPoint;
958 if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
959 closestGridPoint.setSource(p.getSourceType());
960 closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
961 sp_list.push_back(closestGridPoint);
962 }
964 // search for the closest snapped intersection of guide lines
965 Inkscape::SnappedPoint closestGuidePoint;
966 if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
967 closestGuidePoint.setSource(p.getSourceType());
968 closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
969 sp_list.push_back(closestGuidePoint);
970 }
972 // search for the closest snapped intersection of grid with guide lines
973 if (snapprefs.getSnapIntersectionGG()) {
974 Inkscape::SnappedPoint closestGridGuidePoint;
975 if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
976 closestGridGuidePoint.setSource(p.getSourceType());
977 closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
978 sp_list.push_back(closestGridGuidePoint);
979 }
980 }
981 }
983 // now let's see which snapped point gets a thumbs up
984 Inkscape::SnappedPoint bestSnappedPoint(p.getPoint());
985 // std::cout << "Finding the best snap..." << std::endl;
986 for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
987 // first find out if this snapped point is within snapping range
988 // std::cout << "sp = " << (*i).getPoint() << " | source = " << (*i).getSource() << " | target = " << (*i).getTarget();
989 if ((*i).getSnapDistance() <= (*i).getTolerance()) {
990 // if it's the first point, or if it is closer than the best snapped point so far
991 if (i == sp_list.begin() || bestSnappedPoint.isOtherSnapBetter(*i, false)) {
992 // then prefer this point over the previous one
993 bestSnappedPoint = *i;
994 }
995 }
996 // std::cout << std::endl;
997 }
999 // Update the snap indicator, if requested
1000 if (_snapindicator) {
1001 if (bestSnappedPoint.getSnapped()) {
1002 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
1003 } else {
1004 _desktop->snapindicator->remove_snaptarget();
1005 }
1006 }
1008 // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl;
1009 return bestSnappedPoint;
1010 }
1012 /// Convenience shortcut when there is only one item to ignore
1013 void SnapManager::setup(SPDesktop const *desktop,
1014 bool snapindicator,
1015 SPItem const *item_to_ignore,
1016 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1017 SPGuide *guide_to_ignore)
1018 {
1019 g_assert(desktop != NULL);
1020 _items_to_ignore.clear();
1021 _items_to_ignore.push_back(item_to_ignore);
1022 _desktop = desktop;
1023 _snapindicator = snapindicator;
1024 _unselected_nodes = unselected_nodes;
1025 _guide_to_ignore = guide_to_ignore;
1026 }
1028 /**
1029 * \brief Prepare the snap manager for the actual snapping, which includes building a list of snap targets
1030 * to ignore and toggling the snap indicator
1031 *
1032 * There are two overloaded setup() methods, of which the other one only allows for a single item to be ignored
1033 * whereas this one will take a list of items to ignore
1034 *
1035 * \param desktop Reference to the desktop to which this snap manager is attached
1036 * \param snapindicator If true then a snap indicator will be displayed automatically (when enabled in the preferences)
1037 * \param items_to_ignore These items will not be snapped to, e.g. the items that are currently being dragged. This avoids "self-snapping"
1038 * \param unselected_nodes Stationary nodes of the path that is currently being edited in the node tool and
1039 * that can be snapped too. Nodes not in this list will not be snapped to, to avoid "self-snapping". Of each
1040 * unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored
1041 * \param guide_to_ignore Guide that is currently being dragged and should not be snapped to
1042 */
1044 void SnapManager::setup(SPDesktop const *desktop,
1045 bool snapindicator,
1046 std::vector<SPItem const *> &items_to_ignore,
1047 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1048 SPGuide *guide_to_ignore)
1049 {
1050 g_assert(desktop != NULL);
1051 _items_to_ignore = items_to_ignore;
1052 _desktop = desktop;
1053 _snapindicator = snapindicator;
1054 _unselected_nodes = unselected_nodes;
1055 _guide_to_ignore = guide_to_ignore;
1056 }
1058 /// Setup, taking the list of items to ignore from the desktop's selection.
1059 void SnapManager::setupIgnoreSelection(SPDesktop const *desktop,
1060 bool snapindicator,
1061 std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes,
1062 SPGuide *guide_to_ignore)
1063 {
1064 _desktop = desktop;
1065 _snapindicator = snapindicator;
1066 _unselected_nodes = unselected_nodes;
1067 _guide_to_ignore = guide_to_ignore;
1068 _items_to_ignore.clear();
1070 Inkscape::Selection *sel = _desktop->selection;
1071 GSList const *items = sel->itemList();
1072 for (GSList *i = const_cast<GSList*>(items); i; i = i->next) {
1073 _items_to_ignore.push_back(static_cast<SPItem const *>(i->data));
1074 }
1075 }
1077 SPDocument *SnapManager::getDocument() const
1078 {
1079 return _named_view->document;
1080 }
1082 /**
1083 * \brief Takes an untransformed point, applies the given transformation, and returns the transformed point. Eliminates lots of duplicated code
1084 *
1085 * \param p The untransformed position of the point, paired with an identifier of the type of the snap source.
1086 * \param transformation_type Type of transformation to apply.
1087 * \param transformation Mathematical description of the transformation; details depend on the type.
1088 * \param origin Origin of the transformation, if applicable.
1089 * \param dim Dimension to which the transformation applies, if applicable.
1090 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
1091 * \return The position of the point after transformation
1092 */
1094 Geom::Point SnapManager::_transformPoint(Inkscape::SnapCandidatePoint const &p,
1095 Transformation const transformation_type,
1096 Geom::Point const &transformation,
1097 Geom::Point const &origin,
1098 Geom::Dim2 const dim,
1099 bool const uniform) const
1100 {
1101 /* Work out the transformed version of this point */
1102 Geom::Point transformed;
1103 switch (transformation_type) {
1104 case TRANSLATION:
1105 transformed = p.getPoint() + transformation;
1106 break;
1107 case SCALE:
1108 transformed = (p.getPoint() - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
1109 break;
1110 case STRETCH:
1111 {
1112 Geom::Scale s(1, 1);
1113 if (uniform)
1114 s[Geom::X] = s[Geom::Y] = transformation[dim];
1115 else {
1116 s[dim] = transformation[dim];
1117 s[1 - dim] = 1;
1118 }
1119 transformed = ((p.getPoint() - origin) * s) + origin;
1120 break;
1121 }
1122 case SKEW:
1123 // Apply the skew factor
1124 transformed[dim] = (p.getPoint())[dim] + transformation[0] * ((p.getPoint())[1 - dim] - origin[1 - dim]);
1125 // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
1126 // Apply that scale factor here
1127 transformed[1-dim] = (p.getPoint() - origin)[1 - dim] * transformation[1] + origin[1 - dim];
1128 break;
1129 default:
1130 g_assert_not_reached();
1131 }
1133 return transformed;
1134 }
1136 /**
1137 * \brief Mark the location of the snap source (not the snap target!) on the canvas by drawing a symbol
1138 *
1139 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
1140 * \param p The transformed position of the source point, paired with an identifier of the type of the snap source.
1141 */
1143 void SnapManager::_displaySnapsource(Inkscape::SnapCandidatePoint const &p) const {
1145 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
1146 if (prefs->getBool("/options/snapclosestonly/value")) {
1147 bool p_is_a_node = p.getSourceType() & Inkscape::SNAPSOURCE_NODE_CATEGORY;
1148 bool p_is_a_bbox = p.getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY;
1150 if (snapprefs.getSnapEnabledGlobally() && ((p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) {
1151 _desktop->snapindicator->set_new_snapsource(p);
1152 } else {
1153 _desktop->snapindicator->remove_snapsource();
1154 }
1155 }
1156 }
1158 /*
1159 Local Variables:
1160 mode:c++
1161 c-file-style:"stroustrup"
1162 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1163 indent-tabs-mode:nil
1164 fill-column:99
1165 End:
1166 */
1167 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :