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) 1999-2009 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: SnapManager::setup() must have been called before calling this method,
163 * but only once for a set of points
164 *
165 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
166 * \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred
167 * \param source_type Detailed description of the source type, will be used by the snap indicator
168 * \param first_point If true then this point is the first one from a set of points, all from the same selection and having the same transformation
169 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
170 */
172 void SnapManager::freeSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
173 Geom::Point &p,
174 Inkscape::SnapSourceType const source_type,
175 bool first_point,
176 Geom::OptRect const &bbox_to_snap) const
177 {
178 //TODO: PointType and source_type are somewhat redundant; can't we get rid of the point_type parameter?
179 Inkscape::SnappedPoint const s = freeSnap(point_type, p, source_type, first_point, bbox_to_snap);
180 s.getPoint(p);
181 }
184 /**
185 * \brief Try to snap a point to grids, guides or objects.
186 *
187 * Try to snap a point to grids, guides or objects, in two degrees-of-freedom,
188 * i.e. snap in any direction on the two dimensional canvas to the nearest
189 * snap target. freeSnap() is equal in snapping behavior to
190 * freeSnapReturnByRef(). Please read the comments of the latter for more details
191 *
192 * PS: SnapManager::setup() must have been called before calling this method,
193 * but only once for a set of points
194 *
195 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
196 * \param p Current position of the snap source
197 * \param source_type Detailed description of the source type, will be used by the snap indicator
198 * \param first_point If true then this point is the first one from a set of points, all from the same selection and having the same transformation
199 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
200 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
201 */
204 Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::SnapPreferences::PointType point_type,
205 Geom::Point const &p,
206 Inkscape::SnapSourceType const &source_type,
207 bool first_point,
208 Geom::OptRect const &bbox_to_snap) const
209 {
210 if (!someSnapperMightSnap()) {
211 return Inkscape::SnappedPoint(p, source_type, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
212 }
214 SnappedConstraints sc;
215 SnapperList const snappers = getSnappers();
217 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
218 (*i)->freeSnap(sc, point_type, p, source_type, first_point, bbox_to_snap, &_items_to_ignore, _unselected_nodes);
219 }
221 return findBestSnap(p, source_type, sc, false);
222 }
224 /**
225 * \brief Snap to the closest multiple of a grid pitch
226 *
227 * When pasting, we would like to snap to the grid. Problem is that we don't know which
228 * nodes were aligned to the grid at the time of copying, so we don't know which nodes
229 * to snap. If we'd snap an unaligned node to the grid, previously aligned nodes would
230 * become unaligned. That's undesirable. Instead we will make sure that the offset
231 * between the source and its pasted copy is a multiple of the grid pitch. If the source
232 * was aligned, then the copy will therefore also be aligned.
233 *
234 * PS: Whether we really find a multiple also depends on the snapping range! Most users
235 * will have "always snap" enabled though, in which case a multiple will always be found.
236 * PS2: When multiple grids are present then the result will become ambiguous. There is no
237 * way to control to which grid this method will snap.
238 *
239 * \param t Vector that represents the offset of the pasted copy with respect to the original
240 * \return Offset vector after snapping to the closest multiple of a grid pitch
241 */
243 Geom::Point SnapManager::multipleOfGridPitch(Geom::Point const &t) const
244 {
245 if (!snapprefs.getSnapEnabledGlobally()) // No need to check for snapprefs.getSnapPostponedGlobally() here
246 return t;
248 if (_desktop && _desktop->gridsEnabled()) {
249 bool success = false;
250 Geom::Point nearest_multiple;
251 Geom::Coord nearest_distance = NR_HUGE;
253 // It will snap to the grid for which we find the closest snap. This might be a different
254 // grid than to which the objects were initially aligned. I don't see an easy way to fix
255 // this, so when using multiple grids one can get unexpected results
257 // Cannot use getGridSnappers() because we need both the grids AND their snappers
258 // Therefore we iterate through all grids manually
259 for (GSList const *l = _named_view->grids; l != NULL; l = l->next) {
260 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
261 const Inkscape::Snapper* snapper = grid->snapper;
262 if (snapper && snapper->ThisSnapperMightSnap()) {
263 // To find the nearest multiple of the grid pitch for a given translation t, we
264 // will use the grid snapper. Simply snapping the value t to the grid will do, but
265 // only if the origin of the grid is at (0,0). If it's not then compensate for this
266 // in the translation t
267 Geom::Point const t_offset = t + grid->origin;
268 SnappedConstraints sc;
269 // Only the first three parameters are being used for grid snappers
270 snapper->freeSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_NODE, t_offset, Inkscape::SNAPSOURCE_UNDEFINED, TRUE, Geom::OptRect(), NULL, NULL);
271 // Find the best snap for this grid, including intersections of the grid-lines
272 Inkscape::SnappedPoint s = findBestSnap(t_offset, Inkscape::SNAPSOURCE_UNDEFINED, sc, false);
273 if (s.getSnapped() && (s.getSnapDistance() < nearest_distance)) {
274 // use getSnapDistance() instead of getWeightedDistance() here because the pointer's position
275 // doesn't tell us anything about which node to snap
276 success = true;
277 nearest_multiple = s.getPoint() - to_2geom(grid->origin);
278 nearest_distance = s.getSnapDistance();
279 }
280 }
281 }
283 if (success)
284 return nearest_multiple;
285 }
287 return t;
288 }
290 /**
291 * \brief Try to snap a point along a constraint line to grids, guides or objects.
292 *
293 * Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
294 * i.e. snap in a specific direction on the two dimensional canvas to the nearest
295 * snap target.
296 *
297 * constrainedSnapReturnByRef() is equal in snapping behavior to
298 * constrainedSnap(), but the former returns the snapped point trough the referenced
299 * parameter p. This parameter p initially contains the position of the snap
300 * source and will we overwritten by the target position if snapping has occurred.
301 * This makes snapping transparent to the calling code. If this is not desired
302 * because either the calling code must know whether snapping has occurred, or
303 * because the original position should not be touched, then constrainedSnap() should
304 * be called instead.
305 *
306 * PS: SnapManager::setup() must have been called before calling this method,
307 * but only once for a set of points
308 *
309 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
310 * \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred
311 * \param source_type Detailed description of the source type, will be used by the snap indicator
312 * \param constraint The direction or line along which snapping must occur
313 * \param first_point If true then this point is the first one from a set of points, all from the same selection and having the same transformation
314 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
315 */
317 void SnapManager::constrainedSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
318 Geom::Point &p,
319 Inkscape::SnapSourceType const source_type,
320 Inkscape::Snapper::ConstraintLine const &constraint,
321 bool first_point,
322 Geom::OptRect const &bbox_to_snap) const
323 {
324 Inkscape::SnappedPoint const s = constrainedSnap(point_type, p, source_type, constraint, first_point, bbox_to_snap);
325 s.getPoint(p);
326 }
328 /**
329 * \brief Try to snap a point along a constraint line to grids, guides or objects.
330 *
331 * Try to snap a point to grids, guides or objects, in only one degree-of-freedom,
332 * i.e. snap in a specific direction on the two dimensional canvas to the nearest
333 * snap target. constrainedSnap is equal in snapping behavior to
334 * constrainedSnapReturnByRef(). Please read the comments of the latter for more details.
335 *
336 * PS: SnapManager::setup() must have been called before calling this method,
337 * but only once for a set of points
338 *
339 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
340 * \param p Current position of the snap source
341 * \param source_type Detailed description of the source type, will be used by the snap indicator
342 * \param constraint The direction or line along which snapping must occur
343 * \param first_point If true then this point is the first one from a set of points, all from the same selection and having the same transformation
344 * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation
345 */
347 Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::SnapPreferences::PointType point_type,
348 Geom::Point const &p,
349 Inkscape::SnapSourceType const &source_type,
350 Inkscape::Snapper::ConstraintLine const &constraint,
351 bool first_point,
352 Geom::OptRect const &bbox_to_snap) const
353 {
354 if (!someSnapperMightSnap()) {
355 return Inkscape::SnappedPoint(p, source_type, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
356 }
358 // First project the mouse pointer onto the constraint
359 Geom::Point pp = constraint.projection(p);
360 // Then try to snap the projected point
362 SnappedConstraints sc;
363 SnapperList const snappers = getSnappers();
364 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
365 (*i)->constrainedSnap(sc, point_type, pp, source_type, first_point, bbox_to_snap, constraint, &_items_to_ignore);
366 }
368 return findBestSnap(pp, source_type, sc, true);
369 }
371 /**
372 * \brief Try to snap a point of a guide to another guide or to a node
373 *
374 * Try to snap a point of a guide to another guide or to a node in two degrees-
375 * of-freedom, i.e. snap in any direction on the two dimensional canvas to the
376 * nearest snap target. This method is used when dragging or rotating a guide
377 *
378 * PS: SnapManager::setup() must have been called before calling this method,
379 *
380 * \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
381 * \param guide_normal Vector normal to the guide line
382 */
383 void SnapManager::guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const
384 {
385 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
386 return;
387 }
389 if (!(object.GuidesMightSnap() || snapprefs.getSnapToGuides())) {
390 return;
391 }
393 Inkscape::SnapSourceType source_type = Inkscape::SNAPSOURCE_GUIDE_ORIGIN;
394 if (drag_type == SP_DRAG_ROTATE) {
395 source_type = Inkscape::SNAPSOURCE_GUIDE;
396 }
398 // Snap to nodes
399 SnappedConstraints sc;
400 if (object.GuidesMightSnap()) {
401 object.guideFreeSnap(sc, p, guide_normal);
402 }
404 // Snap to guides & grid lines
405 SnapperList snappers = getGridSnappers();
406 snappers.push_back(&guide);
407 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
408 (*i)->freeSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, source_type, true, Geom::OptRect(), NULL, NULL);
409 }
411 // Snap to intersections of curves, but not to the curves themselves! (see _snapTranslatingGuideToNodes in object-snapper.cpp)
412 Inkscape::SnappedPoint const s = findBestSnap(p, source_type, sc, false, true);
414 s.getPoint(p);
415 }
417 /**
418 * \brief Try to snap a point on a guide to the intersection with another guide or a path
419 *
420 * Try to snap a point on a guide to the intersection of that guide with another
421 * guide or with a path. The snapped point will lie somewhere on the guide-line,
422 * making this is a constrained snap, i.e. in only one degree-of-freedom.
423 * This method is used when dragging the origin of the guide along the guide itself.
424 *
425 * PS: SnapManager::setup() must have been called before calling this method,
426 *
427 * \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
428 * \param guide_normal Vector normal to the guide line
429 */
431 void SnapManager::guideConstrainedSnap(Geom::Point &p, SPGuide const &guideline) const
432 {
433 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
434 return;
435 }
437 if (!(object.ThisSnapperMightSnap() || snapprefs.getSnapToGuides())) {
438 return;
439 }
441 Inkscape::SnapSourceType source_type = Inkscape::SNAPSOURCE_GUIDE_ORIGIN;
443 // Snap to nodes or paths
444 SnappedConstraints sc;
445 Inkscape::Snapper::ConstraintLine cl(guideline.point_on_line, Geom::rot90(guideline.normal_to_line));
446 if (object.ThisSnapperMightSnap()) {
447 object.constrainedSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, source_type, true, Geom::OptRect(), cl, NULL);
448 }
450 // Snap to guides & grid lines
451 SnapperList snappers = getGridSnappers();
452 snappers.push_back(&guide);
453 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
454 (*i)->constrainedSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, source_type, true, Geom::OptRect(), cl, NULL);
455 }
457 Inkscape::SnappedPoint const s = findBestSnap(p, source_type, sc, false);
458 s.getPoint(p);
459 }
461 /**
462 * \brief Method for snapping sets of points while they are being transformed
463 *
464 * Method for snapping sets of points while they are being transformed, when using
465 * for example the selector tool. This method is for internal use only, and should
466 * not have to be called directly. Use freeSnapTransalation(), constrainedSnapScale(),
467 * etc. instead.
468 *
469 * This is what is being done in this method: transform each point, find out whether
470 * a free snap or constrained snap is more appropriate, do the snapping, calculate
471 * some metrics to quantify the snap "distance", and see if it's better than the
472 * previous snap. Finally, the best ("nearest") snap from all these points is returned.
473 *
474 * \param type Category of points to which the source point belongs: node or bounding box.
475 * \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.
476 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
477 * \param constrained true if the snap is constrained, e.g. for stretching or for purely horizontal translation.
478 * \param constraint The direction or line along which snapping must occur, if 'constrained' is true; otherwise undefined.
479 * \param transformation_type Type of transformation to apply to points before trying to snap them.
480 * \param transformation Description of the transformation; details depend on the type.
481 * \param origin Origin of the transformation, if applicable.
482 * \param dim Dimension to which the transformation applies, if applicable.
483 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
484 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
485 */
487 Inkscape::SnappedPoint SnapManager::_snapTransformed(
488 Inkscape::SnapPreferences::PointType type,
489 std::vector<std::pair<Geom::Point, int> > const &points,
490 Geom::Point const &pointer,
491 bool constrained,
492 Inkscape::Snapper::ConstraintLine const &constraint,
493 Transformation transformation_type,
494 Geom::Point const &transformation,
495 Geom::Point const &origin,
496 Geom::Dim2 dim,
497 bool uniform) const
498 {
499 /* We have a list of points, which we are proposing to transform in some way. We need to see
500 ** if any of these points, when transformed, snap to anything. If they do, we return the
501 ** appropriate transformation with `true'; otherwise we return the original scale with `false'.
502 */
504 /* Quick check to see if we have any snappers that are enabled
505 ** Also used to globally disable all snapping
506 */
507 if (someSnapperMightSnap() == false) {
508 return Inkscape::SnappedPoint();
509 }
511 std::vector<std::pair<Geom::Point, int> > transformed_points;
512 Geom::Rect bbox;
514 for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = points.begin(); i != points.end(); i++) {
516 /* Work out the transformed version of this point */
517 Geom::Point transformed = _transformPoint(*i, transformation_type, transformation, origin, dim, uniform);
519 // add the current transformed point to the box hulling all transformed points
520 if (i == points.begin()) {
521 bbox = Geom::Rect(transformed, transformed);
522 } else {
523 bbox.expandTo(transformed);
524 }
526 transformed_points.push_back(std::make_pair(transformed, (*i).second));
527 }
529 /* The current best transformation */
530 Geom::Point best_transformation = transformation;
532 /* The current best metric for the best transformation; lower is better, NR_HUGE
533 ** means that we haven't snapped anything.
534 */
535 Geom::Point best_scale_metric(NR_HUGE, NR_HUGE);
536 Inkscape::SnappedPoint best_snapped_point;
537 g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point
538 g_assert(best_snapped_point.getAtIntersection() == false);
540 std::vector<std::pair<Geom::Point, int> >::const_iterator j = transformed_points.begin();
542 // std::cout << std::endl;
543 for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = points.begin(); i != points.end(); i++) {
545 /* Snap it */
546 Inkscape::SnappedPoint snapped_point;
547 Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint;
548 Geom::Point const b = ((*i).first - origin); // vector to original point
550 if (constrained) {
551 if ((transformation_type == SCALE || transformation_type == STRETCH) && uniform) {
552 // When uniformly scaling, each point will have its own unique constraint line,
553 // running from the scaling origin to the original untransformed point. We will
554 // calculate that line here
555 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, b);
556 } else if (transformation_type == STRETCH) { // when non-uniform stretching {
557 dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i).first, component_vectors[dim]);
558 } else if (transformation_type == TRANSLATION) {
559 // When doing a constrained translation, all points will move in the same direction, i.e.
560 // either horizontally or vertically. The lines along which they move are therefore all
561 // parallel, but might not be colinear. Therefore we will have to set the point through
562 // which the constraint-line runs here, for each point individually.
563 dedicated_constraint.setPoint((*i).first);
564 } // else: leave the original constraint, e.g. for skewing
565 if (transformation_type == SCALE && !uniform) {
566 g_warning("Non-uniform constrained scaling is not supported!");
567 }
568 snapped_point = constrainedSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), dedicated_constraint, i == points.begin(), bbox);
569 } else {
570 bool const c1 = fabs(b[Geom::X]) < 1e-6;
571 bool const c2 = fabs(b[Geom::Y]) < 1e-6;
572 if (transformation_type == SCALE && (c1 || c2) && !(c1 && c2)) {
573 // When scaling, a point aligned either horizontally or vertically with the origin can only
574 // move in that specific direction; therefore it should only snap in that direction, otherwise
575 // we will get snapped points with an invalid transformation
576 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, component_vectors[c1]);
577 snapped_point = constrainedSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), dedicated_constraint, i == points.begin(), bbox);
578 } else {
579 snapped_point = freeSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), i == points.begin(), bbox);
580 }
581 }
582 // std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl;
583 snapped_point.setPointerDistance(Geom::L2(pointer - (*i).first));
585 Geom::Point result;
586 Geom::Point scale_metric(NR_HUGE, NR_HUGE);
588 if (snapped_point.getSnapped()) {
589 /* We snapped. Find the transformation that describes where the snapped point has
590 ** ended up, and also the metric for this transformation.
591 */
592 Geom::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point
593 //Geom::Point const b = (*i - origin); // vector to original point
595 switch (transformation_type) {
596 case TRANSLATION:
597 result = snapped_point.getPoint() - (*i).first;
598 /* Consider the case in which a box is almost aligned with a grid in both
599 * horizontal and vertical directions. The distance to the intersection of
600 * the grid lines will always be larger then the distance to a single grid
601 * line. If we prefer snapping to an intersection instead of to a single
602 * grid line, then we cannot use "metric = Geom::L2(result)". Therefore the
603 * snapped distance will be used as a metric. Please note that the snapped
604 * distance is defined as the distance to the nearest line of the intersection,
605 * and not to the intersection itself!
606 */
607 // Only for translations, the relevant metric will be the real snapped distance,
608 // so we don't have to do anything special here
609 break;
610 case SCALE:
611 {
612 result = Geom::Point(NR_HUGE, NR_HUGE);
613 // If this point *i is horizontally or vertically aligned with
614 // the origin of the scaling, then it will scale purely in X or Y
615 // We can therefore only calculate the scaling in this direction
616 // and the scaling factor for the other direction should remain
617 // untouched (unless scaling is uniform ofcourse)
618 for (int index = 0; index < 2; index++) {
619 if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
620 if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
621 result[index] = a[index] / b[index]; // then calculate it!
622 }
623 // we might leave result[1-index] = NR_HUGE
624 // if scaling didn't occur in the other direction
625 }
626 }
627 // Compare the resulting scaling with the desired scaling
628 scale_metric = result - transformation; // One or both of its components might be NR_HUGE
629 break;
630 }
631 case STRETCH:
632 result = Geom::Point(NR_HUGE, NR_HUGE);
633 if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
634 result[dim] = a[dim] / b[dim];
635 result[1-dim] = uniform ? result[dim] : 1;
636 } else { // STRETCHING might occur for this point, but only when the stretching is uniform
637 if (uniform && fabs(b[1-dim]) > 1e-6) {
638 result[1-dim] = a[1-dim] / b[1-dim];
639 result[dim] = result[1-dim];
640 }
641 }
642 // Store the metric for this transformation as a virtual distance
643 snapped_point.setSnapDistance(std::abs(result[dim] - transformation[dim]));
644 snapped_point.setSecondSnapDistance(NR_HUGE);
645 break;
646 case SKEW:
647 result[0] = (snapped_point.getPoint()[dim] - ((*i).first)[dim]) / (((*i).first)[1 - dim] - origin[1 - dim]); // skew factor
648 result[1] = transformation[1]; // scale factor
649 // Store the metric for this transformation as a virtual distance
650 snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
651 snapped_point.setSecondSnapDistance(NR_HUGE);
652 break;
653 default:
654 g_assert_not_reached();
655 }
657 // When scaling, we're considering the best transformation in each direction separately. We will have a metric in each
658 // direction, whereas for all other transformation we only a single one-dimensional metric. That's why we need to handle
659 // the scaling metric differently
660 if (transformation_type == SCALE) {
661 for (int index = 0; index < 2; index++) {
662 if (fabs(scale_metric[index]) < fabs(best_scale_metric[index])) {
663 best_transformation[index] = result[index];
664 best_scale_metric[index] = fabs(scale_metric[index]);
665 // When scaling, we're considering the best transformation in each direction separately
666 // Therefore two different snapped points might together make a single best transformation
667 // We will however return only a single snapped point (e.g. to display the snapping indicator)
668 best_snapped_point = snapped_point;
669 // std::cout << "SEL ";
670 } // else { std::cout << " ";}
671 }
672 if (uniform) {
673 if (best_scale_metric[0] < best_scale_metric[1]) {
674 best_transformation[1] = best_transformation[0];
675 best_scale_metric[1] = best_scale_metric[0];
676 } else {
677 best_transformation[0] = best_transformation[1];
678 best_scale_metric[0] = best_scale_metric[1];
679 }
680 }
681 } else { // For all transformations other than scaling
682 if (best_snapped_point.isOtherSnapBetter(snapped_point, true)) {
683 best_transformation = result;
684 best_snapped_point = snapped_point;
685 }
686 }
687 }
689 j++;
690 }
692 Geom::Coord best_metric;
693 if (transformation_type == SCALE) {
694 // When scaling, don't ever exit with one of scaling components set to NR_HUGE
695 for (int index = 0; index < 2; index++) {
696 if (best_transformation[index] == NR_HUGE) {
697 if (uniform && best_transformation[1-index] < NR_HUGE) {
698 best_transformation[index] = best_transformation[1-index];
699 } else {
700 best_transformation[index] = transformation[index];
701 }
702 }
703 }
704 best_metric = std::min(best_scale_metric[0], best_scale_metric[1]);
705 } else { // For all transformations other than scaling
706 best_metric = best_snapped_point.getSnapDistance();
707 }
709 best_snapped_point.setTransformation(best_transformation);
710 // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
711 // These rounding errors might be caused by NRRects, see bug #1584301
712 best_snapped_point.setSnapDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
713 return best_snapped_point;
714 }
717 /**
718 * \brief Apply a translation to a set of points and try to snap freely in 2 degrees-of-freedom
719 *
720 * \param point_type Category of points to which the source point belongs: node or bounding box.
721 * \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.
722 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
723 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred
724 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
725 */
727 Inkscape::SnappedPoint SnapManager::freeSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
728 std::vector<std::pair<Geom::Point, int> > const &p,
729 Geom::Point const &pointer,
730 Geom::Point const &tr) const
731 {
732 if (p.size() == 1) {
733 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false), (p.at(0)).second));
734 }
736 return _snapTransformed(point_type, p, pointer, false, Geom::Point(0,0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
737 }
739 /**
740 * \brief Apply a translation to a set of points and try to snap along a constraint
741 *
742 * \param point_type Category of points to which the source point belongs: node or bounding box.
743 * \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.
744 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
745 * \param constraint The direction or line along which snapping must occur.
746 * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred.
747 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
748 */
750 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
751 std::vector<std::pair<Geom::Point, int> > const &p,
752 Geom::Point const &pointer,
753 Inkscape::Snapper::ConstraintLine const &constraint,
754 Geom::Point const &tr) const
755 {
756 if (p.size() == 1) {
757 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false), (p.at(0)).second));
758 }
760 return _snapTransformed(point_type, p, pointer, true, constraint, TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
761 }
764 /**
765 * \brief Apply a scaling to a set of points and try to snap freely in 2 degrees-of-freedom
766 *
767 * \param point_type Category of points to which the source point belongs: node or bounding box.
768 * \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.
769 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
770 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
771 * \param o Origin of the scaling
772 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
773 */
775 Inkscape::SnappedPoint SnapManager::freeSnapScale(Inkscape::SnapPreferences::PointType point_type,
776 std::vector<std::pair<Geom::Point, int> > const &p,
777 Geom::Point const &pointer,
778 Geom::Scale const &s,
779 Geom::Point const &o) const
780 {
781 if (p.size() == 1) {
782 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false), (p.at(0)).second));
783 }
785 return _snapTransformed(point_type, p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
786 }
789 /**
790 * \brief Apply a scaling to a set of points and snap such that the aspect ratio of the selection is preserved
791 *
792 * \param point_type Category of points to which the source point belongs: node or bounding box.
793 * \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.
794 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
795 * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred
796 * \param o Origin of the scaling
797 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
798 */
800 Inkscape::SnappedPoint SnapManager::constrainedSnapScale(Inkscape::SnapPreferences::PointType point_type,
801 std::vector<std::pair<Geom::Point, int> > const &p,
802 Geom::Point const &pointer,
803 Geom::Scale const &s,
804 Geom::Point const &o) const
805 {
806 // When constrained scaling, only uniform scaling is supported.
807 if (p.size() == 1) {
808 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true), (p.at(0)).second));
809 }
811 return _snapTransformed(point_type, p, pointer, true, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
812 }
814 /**
815 * \brief Apply a stretch to a set of points and snap such that the direction of the stretch is preserved
816 *
817 * \param point_type Category of points to which the source point belongs: node or bounding box.
818 * \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.
819 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
820 * \param s Proposed stretch; the final stretch can only be calculated after snapping has occurred
821 * \param o Origin of the stretching
822 * \param d Dimension in which to apply proposed stretch.
823 * \param u true if the stretch should be uniform (i.e. to be applied equally in both dimensions)
824 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
825 */
827 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(Inkscape::SnapPreferences::PointType point_type,
828 std::vector<std::pair<Geom::Point, int> > const &p,
829 Geom::Point const &pointer,
830 Geom::Coord const &s,
831 Geom::Point const &o,
832 Geom::Dim2 d,
833 bool u) const
834 {
835 if (p.size() == 1) {
836 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), STRETCH, Geom::Point(s, s), o, d, u), (p.at(0)).second));
837 }
839 return _snapTransformed(point_type, p, pointer, true, Geom::Point(0,0), STRETCH, Geom::Point(s, s), o, d, u);
840 }
842 /**
843 * \brief Apply a skew to a set of points and snap such that the direction of the skew is preserved
844 *
845 * \param point_type Category of points to which the source point belongs: node or bounding box.
846 * \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.
847 * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed).
848 * \param constraint The direction or line along which snapping must occur.
849 * \param s Proposed skew; the final skew can only be calculated after snapping has occurred
850 * \param o Origin of the proposed skew
851 * \param d Dimension in which to apply proposed skew.
852 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics.
853 */
855 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(Inkscape::SnapPreferences::PointType point_type,
856 std::vector<std::pair<Geom::Point, int> > const &p,
857 Geom::Point const &pointer,
858 Inkscape::Snapper::ConstraintLine const &constraint,
859 Geom::Point const &s,
860 Geom::Point const &o,
861 Geom::Dim2 d) const
862 {
863 // "s" contains skew factor in s[0], and scale factor in s[1]
865 // Snapping the nodes of the bounding box of a selection that is being transformed, will only work if
866 // the transformation of the bounding box is equal to the transformation of the individual nodes. This is
867 // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
868 // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
869 // of bounding boxes is not allowed here.
870 g_assert(!(point_type & Inkscape::SnapPreferences::SNAPPOINT_BBOX));
872 if (p.size() == 1) {
873 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), SKEW, s, o, d, false), (p.at(0)).second));
874 }
876 return _snapTransformed(point_type, p, pointer, true, constraint, SKEW, s, o, d, false);
877 }
879 /**
880 * \brief Given a set of possible snap targets, find the best target (which is not necessarily
881 * also the nearest target), and show the snap indicator if requested
882 *
883 * \param p Current position of the snap source
884 * \param source_type Detailed description of the source type, will be used by the snap indicator
885 * \param sc A structure holding all snap targets that have been found so far
886 * \param constrained True if the snap is constrained, e.g. for stretching or for purely horizontal translation.
887 * \param noCurves If true, then do consider snapping to intersections of curves, but not to the curves themself
888 * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics
889 */
891 Inkscape::SnappedPoint SnapManager::findBestSnap(Geom::Point const &p,
892 Inkscape::SnapSourceType const source_type,
893 SnappedConstraints &sc,
894 bool constrained,
895 bool noCurves) const
896 {
898 /*
899 std::cout << "Type and number of snapped constraints: " << std::endl;
900 std::cout << " Points : " << sc.points.size() << std::endl;
901 std::cout << " Lines : " << sc.lines.size() << std::endl;
902 std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
903 std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
904 std::cout << " Curves : " << sc.curves.size()<< std::endl;
905 */
907 // Store all snappoints
908 std::list<Inkscape::SnappedPoint> sp_list;
910 // search for the closest snapped point
911 Inkscape::SnappedPoint closestPoint;
912 if (getClosestSP(sc.points, closestPoint)) {
913 sp_list.push_back(closestPoint);
914 }
916 // search for the closest snapped curve
917 if (!noCurves) {
918 Inkscape::SnappedCurve closestCurve;
919 if (getClosestCurve(sc.curves, closestCurve)) {
920 sp_list.push_back(Inkscape::SnappedPoint(closestCurve));
921 }
922 }
924 if (snapprefs.getSnapIntersectionCS()) {
925 // search for the closest snapped intersection of curves
926 Inkscape::SnappedPoint closestCurvesIntersection;
927 if (getClosestIntersectionCS(sc.curves, p, closestCurvesIntersection, _desktop->dt2doc())) {
928 closestCurvesIntersection.setSource(source_type);
929 sp_list.push_back(closestCurvesIntersection);
930 }
931 }
933 // search for the closest snapped grid line
934 Inkscape::SnappedLine closestGridLine;
935 if (getClosestSL(sc.grid_lines, closestGridLine)) {
936 sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
937 }
939 // search for the closest snapped guide line
940 Inkscape::SnappedLine closestGuideLine;
941 if (getClosestSL(sc.guide_lines, closestGuideLine)) {
942 sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
943 }
945 // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
946 // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
948 // When doing a constrained snap however, we're already at an intersection of the constrained line and
949 // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
950 // no need to look for additional intersections
951 if (!constrained) {
952 // search for the closest snapped intersection of grid lines
953 Inkscape::SnappedPoint closestGridPoint;
954 if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
955 closestGridPoint.setSource(source_type);
956 closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
957 sp_list.push_back(closestGridPoint);
958 }
960 // search for the closest snapped intersection of guide lines
961 Inkscape::SnappedPoint closestGuidePoint;
962 if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
963 closestGuidePoint.setSource(source_type);
964 closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
965 sp_list.push_back(closestGuidePoint);
966 }
968 // search for the closest snapped intersection of grid with guide lines
969 if (snapprefs.getSnapIntersectionGG()) {
970 Inkscape::SnappedPoint closestGridGuidePoint;
971 if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
972 closestGridGuidePoint.setSource(source_type);
973 closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
974 sp_list.push_back(closestGridGuidePoint);
975 }
976 }
977 }
979 // now let's see which snapped point gets a thumbs up
980 Inkscape::SnappedPoint bestSnappedPoint = Inkscape::SnappedPoint(p, Inkscape::SNAPSOURCE_UNDEFINED, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
981 // std::cout << "Finding the best snap..." << std::endl;
982 for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
983 // first find out if this snapped point is within snapping range
984 // std::cout << "sp = " << from_2geom((*i).getPoint());
985 if ((*i).getSnapDistance() <= (*i).getTolerance()) {
986 // if it's the first point, or if it is closer than the best snapped point so far
987 if (i == sp_list.begin() || bestSnappedPoint.isOtherSnapBetter(*i, false)) {
988 // then prefer this point over the previous one
989 bestSnappedPoint = *i;
990 }
991 }
992 // std::cout << std::endl;
993 }
995 // Update the snap indicator, if requested
996 if (_snapindicator) {
997 if (bestSnappedPoint.getSnapped()) {
998 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
999 } else {
1000 _desktop->snapindicator->remove_snaptarget();
1001 }
1002 }
1004 // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl;
1005 return bestSnappedPoint;
1006 }
1008 /// Convenience shortcut when there is only one item to ignore
1009 void SnapManager::setup(SPDesktop const *desktop,
1010 bool snapindicator,
1011 SPItem const *item_to_ignore,
1012 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
1013 SPGuide *guide_to_ignore)
1014 {
1015 g_assert(desktop != NULL);
1016 _items_to_ignore.clear();
1017 _items_to_ignore.push_back(item_to_ignore);
1018 _desktop = desktop;
1019 _snapindicator = snapindicator;
1020 _unselected_nodes = unselected_nodes;
1021 _guide_to_ignore = guide_to_ignore;
1022 }
1024 /**
1025 * \brief Prepare the snap manager for the actual snapping, which includes building a list of snap targets
1026 * to ignore and toggling the snap indicator
1027 *
1028 * There are two overloaded setup() methods, of which the other one only allows for a single item to be ignored
1029 * whereas this one will take a list of items to ignore
1030 *
1031 * \param desktop Reference to the desktop to which this snap manager is attached
1032 * \param snapindicator If true then a snap indicator will be displayed automatically (when enabled in the preferences)
1033 * \param items_to_ignore These items will not be snapped to, e.g. the items that are currently being dragged. This avoids "self-snapping"
1034 * \param unselected_nodes Stationary nodes of the path that is currently being edited in the node tool and
1035 * that can be snapped too. Nodes not in this list will not be snapped to, to avoid "self-snapping". Of each
1036 * unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored
1037 * \param guide_to_ignore Guide that is currently being dragged and should not be snapped to
1038 */
1040 void SnapManager::setup(SPDesktop const *desktop,
1041 bool snapindicator,
1042 std::vector<SPItem const *> const &items_to_ignore,
1043 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
1044 SPGuide *guide_to_ignore)
1045 {
1046 g_assert(desktop != NULL);
1047 _items_to_ignore = items_to_ignore;
1048 _desktop = desktop;
1049 _snapindicator = snapindicator;
1050 _unselected_nodes = unselected_nodes;
1051 _guide_to_ignore = guide_to_ignore;
1052 }
1054 /// Setup, taking the list of items to ignore from the desktop's selection.
1055 void SnapManager::setupIgnoreSelection(SPDesktop const *desktop,
1056 bool snapindicator,
1057 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
1058 SPGuide *guide_to_ignore)
1059 {
1060 _desktop = desktop;
1061 _snapindicator = snapindicator;
1062 _unselected_nodes = unselected_nodes;
1063 _guide_to_ignore = guide_to_ignore;
1064 _items_to_ignore.clear();
1066 Inkscape::Selection *sel = _desktop->selection;
1067 GSList const *items = sel->itemList();
1068 for (GSList *i = const_cast<GSList*>(items); i; i = i->next) {
1069 _items_to_ignore.push_back(static_cast<SPItem const *>(i->data));
1070 }
1071 }
1073 SPDocument *SnapManager::getDocument() const
1074 {
1075 return _named_view->document;
1076 }
1078 /**
1079 * \brief Takes an untransformed point, applies the given transformation, and returns the transformed point. Eliminates lots of duplicated code
1080 *
1081 * \param p The untransformed position of the point, paired with an identifier of the type of the snap source.
1082 * \param transformation_type Type of transformation to apply.
1083 * \param transformation Mathematical description of the transformation; details depend on the type.
1084 * \param origin Origin of the transformation, if applicable.
1085 * \param dim Dimension to which the transformation applies, if applicable.
1086 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
1087 * \return The position of the point after transformation
1088 */
1090 Geom::Point SnapManager::_transformPoint(std::pair<Geom::Point, int> const &p,
1091 Transformation const transformation_type,
1092 Geom::Point const &transformation,
1093 Geom::Point const &origin,
1094 Geom::Dim2 const dim,
1095 bool const uniform) const
1096 {
1097 /* Work out the transformed version of this point */
1098 Geom::Point transformed;
1099 switch (transformation_type) {
1100 case TRANSLATION:
1101 transformed = p.first + transformation;
1102 break;
1103 case SCALE:
1104 transformed = (p.first - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
1105 break;
1106 case STRETCH:
1107 {
1108 Geom::Scale s(1, 1);
1109 if (uniform)
1110 s[Geom::X] = s[Geom::Y] = transformation[dim];
1111 else {
1112 s[dim] = transformation[dim];
1113 s[1 - dim] = 1;
1114 }
1115 transformed = ((p.first - origin) * s) + origin;
1116 break;
1117 }
1118 case SKEW:
1119 // Apply the skew factor
1120 transformed[dim] = (p.first)[dim] + transformation[0] * ((p.first)[1 - dim] - origin[1 - dim]);
1121 // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
1122 // Apply that scale factor here
1123 transformed[1-dim] = (p.first - origin)[1 - dim] * transformation[1] + origin[1 - dim];
1124 break;
1125 default:
1126 g_assert_not_reached();
1127 }
1129 return transformed;
1130 }
1132 /**
1133 * \brief Mark the location of the snap source (not the snap target!) on the canvas by drawing a symbol
1134 *
1135 * \param point_type Category of points to which the source point belongs: node, guide or bounding box
1136 * \param p The transformed position of the source point, paired with an identifier of the type of the snap source.
1137 */
1139 void SnapManager::_displaySnapsource(Inkscape::SnapPreferences::PointType point_type, std::pair<Geom::Point, int> const &p) const {
1141 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
1142 if (prefs->getBool("/options/snapclosestonly/value")) {
1143 bool p_is_a_node = point_type & Inkscape::SnapPreferences::SNAPPOINT_NODE;
1144 bool p_is_a_bbox = point_type & Inkscape::SnapPreferences::SNAPPOINT_BBOX;
1145 if (snapprefs.getSnapEnabledGlobally() && ((p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) {
1146 _desktop->snapindicator->set_new_snapsource(p);
1147 } else {
1148 _desktop->snapindicator->remove_snapsource();
1149 }
1150 }
1151 }
1153 /*
1154 Local Variables:
1155 mode:c++
1156 c-file-style:"stroustrup"
1157 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
1158 indent-tabs-mode:nil
1159 fill-column:99
1160 End:
1161 */
1162 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :