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 "sp-guide.h"
34 #include "preferences.h"
35 #include "event-context.h"
36 using std::vector;
38 /**
39 * Construct a SnapManager for a SPNamedView.
40 *
41 * \param v `Owning' SPNamedView.
42 */
44 SnapManager::SnapManager(SPNamedView const *v) :
45 guide(this, 0),
46 object(this, 0),
47 snapprefs(),
48 _named_view(v)
49 {
50 }
52 /**
53 * \return List of snappers that we use.
54 */
55 SnapManager::SnapperList
56 SnapManager::getSnappers() const
57 {
58 SnapManager::SnapperList s;
59 s.push_back(&guide);
60 s.push_back(&object);
62 SnapManager::SnapperList gs = getGridSnappers();
63 s.splice(s.begin(), gs);
65 return s;
66 }
68 /**
69 * \return List of gridsnappers that we use.
70 */
71 SnapManager::SnapperList
72 SnapManager::getGridSnappers() const
73 {
74 SnapperList s;
76 //FIXME: this code should actually do this: add new grid snappers that are active for this desktop. now it just adds all gridsnappers
77 if (_desktop && _desktop->gridsEnabled() && snapprefs.getSnapToGrids()) {
78 for ( GSList const *l = _named_view->grids; l != NULL; l = l->next) {
79 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
80 s.push_back(grid->snapper);
81 }
82 }
84 return s;
85 }
87 /**
88 * \return true if one of the snappers will try to snap something.
89 */
91 bool SnapManager::someSnapperMightSnap() const
92 {
93 if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) {
94 return false;
95 }
97 SnapperList const s = getSnappers();
98 SnapperList::const_iterator i = s.begin();
99 while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
100 i++;
101 }
103 return (i != s.end());
104 }
106 /**
107 * \return true if one of the snappers will try to snap something.
108 */
110 bool SnapManager::gridSnapperMightSnap() const
111 {
112 if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) {
113 return false;
114 }
116 SnapperList const s = getGridSnappers();
117 SnapperList::const_iterator i = s.begin();
118 while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
119 i++;
120 }
122 return (i != s.end());
123 }
125 /**
126 * Try to snap a point to any of the specified snappers.
127 *
128 * \param point_type Type of point.
129 * \param p Point.
130 * \param first_point If true then this point is the first one from a whole bunch of points
131 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
132 * \param snappers List of snappers to try to snap to
133 * \return Snapped point.
134 */
136 void SnapManager::freeSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
137 Geom::Point &p,
138 Inkscape::SnapSourceType const source_type,
139 bool first_point,
140 Geom::OptRect const &bbox_to_snap) const
141 {
142 Inkscape::SnappedPoint const s = freeSnap(point_type, p, source_type, first_point, bbox_to_snap);
143 s.getPoint(p);
144 }
147 /**
148 * Try to snap a point to any of the specified snappers.
149 *
150 * \param point_type Type of point.
151 * \param p Point.
152 * \param first_point If true then this point is the first one from a whole bunch of points
153 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
154 * \param snappers List of snappers to try to snap to
155 * \return Snapped point.
156 */
158 Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::SnapPreferences::PointType point_type,
159 Geom::Point const &p,
160 Inkscape::SnapSourceType const &source_type,
161 bool first_point,
162 Geom::OptRect const &bbox_to_snap) const
163 {
164 if (_desktop->event_context && _desktop->event_context->_snap_window_open == false) {
165 g_warning("The current tool tries to snap, but it hasn't yet opened the snap window. Please report this!");
166 // When the context goes into dragging-mode, then Inkscape should call this: sp_event_context_snap_window_open(event_context);
167 }
169 //std::cout << "SnapManager::freeSnap -> postponed: " << snapprefs.getSnapPostponedGlobally() << std::endl;
171 if (!someSnapperMightSnap()) {
172 return Inkscape::SnappedPoint(p, source_type, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
173 }
175 std::vector<SPItem const *> *items_to_ignore;
176 if (_item_to_ignore) { // If we have only a single item to ignore
177 // then build a list containing this single item;
178 // This single-item list will prevail over any other _items_to_ignore list, should that exist
179 items_to_ignore = new std::vector<SPItem const *>;
180 items_to_ignore->push_back(_item_to_ignore);
181 } else {
182 items_to_ignore = _items_to_ignore;
183 }
185 SnappedConstraints sc;
186 SnapperList const snappers = getSnappers();
188 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
189 (*i)->freeSnap(sc, point_type, p, source_type, first_point, bbox_to_snap, items_to_ignore, _unselected_nodes);
190 }
192 if (_item_to_ignore) {
193 delete items_to_ignore;
194 }
196 return findBestSnap(p, source_type, sc, false);
197 }
199 // When pasting, we would like to snap to the grid. Problem is that we don't know which nodes were
200 // aligned to the grid at the time of copying, so we don't know which nodes to snap. If we'd snap an
201 // unaligned node to the grid, previously aligned nodes would become unaligned. That's undesirable.
202 // Instead we will make sure that the offset between the source and the copy is a multiple of the grid
203 // pitch. If the source was aligned, then the copy will therefore also be aligned
204 // PS: Whether we really find a multiple also depends on the snapping range!
205 Geom::Point SnapManager::multipleOfGridPitch(Geom::Point const &t) const
206 {
207 if (!snapprefs.getSnapEnabledGlobally()) // No need to check for snapprefs.getSnapPostponedGlobally() here
208 return t;
210 //FIXME: this code should actually do this: add new grid snappers that are active for this desktop. now it just adds all gridsnappers
212 if (_desktop && _desktop->gridsEnabled()) {
213 bool success = false;
214 Geom::Point nearest_multiple;
215 Geom::Coord nearest_distance = NR_HUGE;
217 // It will snap to the grid for which we find the closest snap. This might be a different
218 // grid than to which the objects were initially aligned. I don't see an easy way to fix
219 // this, so when using multiple grids one can get unexpected results
221 // Cannot use getGridSnappers() because we need both the grids AND their snappers
222 // Therefore we iterate through all grids manually
223 for (GSList const *l = _named_view->grids; l != NULL; l = l->next) {
224 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
225 const Inkscape::Snapper* snapper = grid->snapper;
226 if (snapper && snapper->ThisSnapperMightSnap()) {
227 // To find the nearest multiple of the grid pitch for a given translation t, we
228 // will use the grid snapper. Simply snapping the value t to the grid will do, but
229 // only if the origin of the grid is at (0,0). If it's not then compensate for this
230 // in the translation t
231 Geom::Point const t_offset = t + grid->origin;
232 SnappedConstraints sc;
233 // Only the first three parameters are being used for grid snappers
234 snapper->freeSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_NODE, t_offset, Inkscape::SNAPSOURCE_UNDEFINED, TRUE, Geom::OptRect(), NULL, NULL);
235 // Find the best snap for this grid, including intersections of the grid-lines
236 Inkscape::SnappedPoint s = findBestSnap(t_offset, Inkscape::SNAPSOURCE_UNDEFINED, sc, false);
237 if (s.getSnapped() && (s.getSnapDistance() < nearest_distance)) {
238 // use getSnapDistance() instead of getWeightedDistance() here because the pointer's position
239 // doesn't tell us anything about which node to snap
240 success = true;
241 nearest_multiple = s.getPoint() - to_2geom(grid->origin);
242 nearest_distance = s.getSnapDistance();
243 }
244 }
245 }
247 if (success)
248 return nearest_multiple;
249 }
251 return t;
252 }
254 /**
255 * Try to snap a point to any interested snappers. A snap will only occur along
256 * a line described by a Inkscape::Snapper::ConstraintLine.
257 *
258 * \param point_type Type of point.
259 * \param p Point.
260 * \param first_point If true then this point is the first one from a whole bunch of points
261 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
262 * \param constraint Constraint line.
263 * \return Snapped point.
264 */
266 void SnapManager::constrainedSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
267 Geom::Point &p,
268 Inkscape::SnapSourceType const source_type,
269 Inkscape::Snapper::ConstraintLine const &constraint,
270 bool const snap_projection,
271 bool first_point,
272 Geom::OptRect const &bbox_to_snap) const
273 {
274 Inkscape::SnappedPoint const s = constrainedSnap(point_type, p, source_type, constraint, snap_projection, first_point, bbox_to_snap);
275 s.getPoint(p);
276 }
279 /**
280 * Try to snap a point to any interested snappers. A snap will only occur along
281 * a line described by a Inkscape::Snapper::ConstraintLine.
282 *
283 * \param point_type Type of point.
284 * \param p Point.
285 * \param first_point If true then this point is the first one from a whole bunch of points
286 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
287 * \param constraint Constraint line.
288 * \return Snapped point.
289 */
291 Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::SnapPreferences::PointType point_type,
292 Geom::Point const &p,
293 Inkscape::SnapSourceType const &source_type,
294 Inkscape::Snapper::ConstraintLine const &constraint,
295 bool /*snap_projection*/,
296 bool first_point,
297 Geom::OptRect const &bbox_to_snap) const
298 {
299 if (_desktop->event_context && _desktop->event_context->_snap_window_open == false) {
300 g_warning("The current tool tries to snap, but it hasn't yet opened the snap window. Please report this!");
301 // When the context goes into dragging-mode, then Inkscape should call this: sp_event_context_snap_window_open(event_context);
302 }
304 if (!someSnapperMightSnap()) {
305 return Inkscape::SnappedPoint(p, source_type, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
306 }
308 std::vector<SPItem const *> *items_to_ignore;
309 if (_item_to_ignore) { // If we have only a single item to ignore
310 // then build a list containing this single item;
311 // This single-item list will prevail over any other _items_to_ignore list, should that exist
312 items_to_ignore = new std::vector<SPItem const *>;
313 items_to_ignore->push_back(_item_to_ignore);
314 } else {
315 items_to_ignore = _items_to_ignore;
316 }
318 Geom::Point pp = constraint.projection(p);
320 SnappedConstraints sc;
321 SnapperList const snappers = getSnappers();
322 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
323 (*i)->constrainedSnap(sc, point_type, pp, source_type, first_point, bbox_to_snap, constraint, items_to_ignore);
324 }
326 if (_item_to_ignore) {
327 delete items_to_ignore;
328 }
330 return findBestSnap(p, source_type, sc, true);
331 }
333 void SnapManager::guideSnap(Geom::Point &p, Geom::Point const &guide_normal) const
334 {
335 // This method is used to snap a guide to nodes or to other guides, while dragging the guide around. Will not snap to grids!
337 if (_desktop->event_context && _desktop->event_context->_snap_window_open == false) {
338 g_warning("The current tool tries to snap, but it hasn't yet opened the snap window. Please report this!");
339 // When the context goes into dragging-mode, then Inkscape should call this: sp_event_context_snap_window_open(event_context);
340 }
342 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
343 return;
344 }
346 if (!(object.GuidesMightSnap() || snapprefs.getSnapToGuides())) {
347 return;
348 }
350 // Snap to nodes
351 SnappedConstraints sc;
352 if (object.GuidesMightSnap()) {
353 object.guideSnap(sc, p, guide_normal);
354 }
356 // Snap to guides
357 if (snapprefs.getSnapToGuides()) {
358 guide.freeSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, Inkscape::SNAPSOURCE_GUIDE, true, Geom::OptRect(), NULL, NULL);
359 }
361 // We won't snap to grids, what's the use?
363 Inkscape::SnappedPoint const s = findBestSnap(p, Inkscape::SNAPSOURCE_GUIDE, sc, false);
364 s.getPoint(p);
365 }
368 /**
369 * Main internal snapping method, which is called by the other, friendlier, public
370 * methods. It's a bit hairy as it has lots of parameters, but it saves on a lot
371 * of duplicated code.
372 *
373 * \param type Type of points being snapped.
374 * \param points List of points to snap (i.e. untransformed).
375 * \param pointer Location of the mouse pointer, at the time when dragging started (i.e. "untransformed")
376 * \param constrained true if the snap is constrained.
377 * \param constraint Constraint line to use, if `constrained' is true, otherwise undefined.
378 * \param transformation_type Type of transformation to apply to points before trying to snap them.
379 * \param transformation Description of the transformation; details depend on the type.
380 * \param origin Origin of the transformation, if applicable.
381 * \param dim Dimension of the transformation, if applicable.
382 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
383 */
385 Inkscape::SnappedPoint SnapManager::_snapTransformed(
386 Inkscape::SnapPreferences::PointType type,
387 std::vector<std::pair<Geom::Point, int> > const &points,
388 Geom::Point const &pointer,
389 bool constrained,
390 Inkscape::Snapper::ConstraintLine const &constraint,
391 Transformation transformation_type,
392 Geom::Point const &transformation,
393 Geom::Point const &origin,
394 Geom::Dim2 dim,
395 bool uniform) const
396 {
397 /* We have a list of points, which we are proposing to transform in some way. We need to see
398 ** if any of these points, when transformed, snap to anything. If they do, we return the
399 ** appropriate transformation with `true'; otherwise we return the original scale with `false'.
400 */
402 /* Quick check to see if we have any snappers that are enabled
403 ** Also used to globally disable all snapping
404 */
405 if (someSnapperMightSnap() == false) {
406 return Inkscape::SnappedPoint();
407 }
409 std::vector<std::pair<Geom::Point, int> > transformed_points;
410 Geom::Rect bbox;
412 for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = points.begin(); i != points.end(); i++) {
414 /* Work out the transformed version of this point */
415 Geom::Point transformed = _transformPoint(*i, transformation_type, transformation, origin, dim, uniform);
417 // add the current transformed point to the box hulling all transformed points
418 if (i == points.begin()) {
419 bbox = Geom::Rect(transformed, transformed);
420 } else {
421 bbox.expandTo(transformed);
422 }
424 transformed_points.push_back(std::make_pair(transformed, (*i).second));
425 }
427 /* The current best transformation */
428 Geom::Point best_transformation = transformation;
430 /* The current best metric for the best transformation; lower is better, NR_HUGE
431 ** means that we haven't snapped anything.
432 */
433 Geom::Point best_scale_metric(NR_HUGE, NR_HUGE);
434 Inkscape::SnappedPoint best_snapped_point;
435 g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point
436 g_assert(best_snapped_point.getAtIntersection() == false);
438 std::vector<std::pair<Geom::Point, int> >::const_iterator j = transformed_points.begin();
440 // std::cout << std::endl;
441 for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = points.begin(); i != points.end(); i++) {
443 /* Snap it */
444 Inkscape::SnappedPoint snapped_point;
445 Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint;
446 Geom::Point const b = ((*i).first - origin); // vector to original point
448 if (constrained) {
449 if ((transformation_type == SCALE || transformation_type == STRETCH) && uniform) {
450 // When uniformly scaling, each point will have its own unique constraint line,
451 // running from the scaling origin to the original untransformed point. We will
452 // calculate that line here
453 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, b);
454 } else if (transformation_type == STRETCH) { // when non-uniform stretching {
455 dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i).first, component_vectors[dim]);
456 } else if (transformation_type == TRANSLATION) {
457 // When doing a constrained translation, all points will move in the same direction, i.e.
458 // either horizontally or vertically. The lines along which they move are therefore all
459 // parallel, but might not be colinear. Therefore we will have to set the point through
460 // which the constraint-line runs here, for each point individually.
461 dedicated_constraint.setPoint((*i).first);
462 } // else: leave the original constraint, e.g. for skewing
463 if (transformation_type == SCALE && !uniform) {
464 g_warning("Non-uniform constrained scaling is not supported!");
465 }
466 snapped_point = constrainedSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), dedicated_constraint, false, i == points.begin(), bbox);
467 } else {
468 bool const c1 = fabs(b[Geom::X]) < 1e-6;
469 bool const c2 = fabs(b[Geom::Y]) < 1e-6;
470 if (transformation_type == SCALE && (c1 || c2) && !(c1 && c2)) {
471 // When scaling, a point aligned either horizontally or vertically with the origin can only
472 // move in that specific direction; therefore it should only snap in that direction, otherwise
473 // we will get snapped points with an invalid transformation
474 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, component_vectors[c1]);
475 snapped_point = constrainedSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), dedicated_constraint, false, i == points.begin(), bbox);
476 } else {
477 snapped_point = freeSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), i == points.begin(), bbox);
478 }
479 }
480 // std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl;
481 snapped_point.setPointerDistance(Geom::L2(pointer - (*i).first));
483 Geom::Point result;
484 Geom::Point scale_metric(NR_HUGE, NR_HUGE);
486 if (snapped_point.getSnapped()) {
487 /* We snapped. Find the transformation that describes where the snapped point has
488 ** ended up, and also the metric for this transformation.
489 */
490 Geom::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point
491 //Geom::Point const b = (*i - origin); // vector to original point
493 switch (transformation_type) {
494 case TRANSLATION:
495 result = snapped_point.getPoint() - (*i).first;
496 /* Consider the case in which a box is almost aligned with a grid in both
497 * horizontal and vertical directions. The distance to the intersection of
498 * the grid lines will always be larger then the distance to a single grid
499 * line. If we prefer snapping to an intersection instead of to a single
500 * grid line, then we cannot use "metric = Geom::L2(result)". Therefore the
501 * snapped distance will be used as a metric. Please note that the snapped
502 * distance is defined as the distance to the nearest line of the intersection,
503 * and not to the intersection itself!
504 */
505 // Only for translations, the relevant metric will be the real snapped distance,
506 // so we don't have to do anything special here
507 break;
508 case SCALE:
509 {
510 result = Geom::Point(NR_HUGE, NR_HUGE);
511 // If this point *i is horizontally or vertically aligned with
512 // the origin of the scaling, then it will scale purely in X or Y
513 // We can therefore only calculate the scaling in this direction
514 // and the scaling factor for the other direction should remain
515 // untouched (unless scaling is uniform ofcourse)
516 for (int index = 0; index < 2; index++) {
517 if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
518 if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
519 result[index] = a[index] / b[index]; // then calculate it!
520 }
521 // we might leave result[1-index] = NR_HUGE
522 // if scaling didn't occur in the other direction
523 }
524 }
525 // Compare the resulting scaling with the desired scaling
526 scale_metric = result - transformation; // One or both of its components might be NR_HUGE
527 break;
528 }
529 case STRETCH:
530 result = Geom::Point(NR_HUGE, NR_HUGE);
531 if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
532 result[dim] = a[dim] / b[dim];
533 result[1-dim] = uniform ? result[dim] : 1;
534 } else { // STRETCHING might occur for this point, but only when the stretching is uniform
535 if (uniform && fabs(b[1-dim]) > 1e-6) {
536 result[1-dim] = a[1-dim] / b[1-dim];
537 result[dim] = result[1-dim];
538 }
539 }
540 // Store the metric for this transformation as a virtual distance
541 snapped_point.setSnapDistance(std::abs(result[dim] - transformation[dim]));
542 snapped_point.setSecondSnapDistance(NR_HUGE);
543 break;
544 case SKEW:
545 result[0] = (snapped_point.getPoint()[dim] - ((*i).first)[dim]) / (((*i).first)[1 - dim] - origin[1 - dim]); // skew factor
546 result[1] = transformation[1]; // scale factor
547 // Store the metric for this transformation as a virtual distance
548 snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
549 snapped_point.setSecondSnapDistance(NR_HUGE);
550 break;
551 default:
552 g_assert_not_reached();
553 }
555 // When scaling, we're considering the best transformation in each direction separately. We will have a metric in each
556 // direction, whereas for all other transformation we only a single one-dimensional metric. That's why we need to handle
557 // the scaling metric differently
558 if (transformation_type == SCALE) {
559 for (int index = 0; index < 2; index++) {
560 if (fabs(scale_metric[index]) < fabs(best_scale_metric[index])) {
561 best_transformation[index] = result[index];
562 best_scale_metric[index] = fabs(scale_metric[index]);
563 // When scaling, we're considering the best transformation in each direction separately
564 // Therefore two different snapped points might together make a single best transformation
565 // We will however return only a single snapped point (e.g. to display the snapping indicator)
566 best_snapped_point = snapped_point;
567 // std::cout << "SEL ";
568 } // else { std::cout << " ";}
569 }
570 if (uniform) {
571 if (best_scale_metric[0] < best_scale_metric[1]) {
572 best_transformation[1] = best_transformation[0];
573 best_scale_metric[1] = best_scale_metric[0];
574 } else {
575 best_transformation[0] = best_transformation[1];
576 best_scale_metric[0] = best_scale_metric[1];
577 }
578 }
579 } else { // For all transformations other than scaling
580 if (best_snapped_point.isOtherSnapBetter(snapped_point, true)) {
581 best_transformation = result;
582 best_snapped_point = snapped_point;
583 }
584 }
585 }
587 j++;
588 }
590 Geom::Coord best_metric;
591 if (transformation_type == SCALE) {
592 // When scaling, don't ever exit with one of scaling components set to NR_HUGE
593 for (int index = 0; index < 2; index++) {
594 if (best_transformation[index] == NR_HUGE) {
595 if (uniform && best_transformation[1-index] < NR_HUGE) {
596 best_transformation[index] = best_transformation[1-index];
597 } else {
598 best_transformation[index] = transformation[index];
599 }
600 }
601 }
602 best_metric = std::min(best_scale_metric[0], best_scale_metric[1]);
603 } else { // For all transformations other than scaling
604 best_metric = best_snapped_point.getSnapDistance();
605 }
607 best_snapped_point.setTransformation(best_transformation);
608 // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
609 // These rounding errors might be caused by NRRects, see bug #1584301
610 best_snapped_point.setSnapDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
611 return best_snapped_point;
612 }
615 /**
616 * Try to snap a list of points to any interested snappers after they have undergone
617 * a translation.
618 *
619 * \param point_type Type of points.
620 * \param p Points.
621 * \param tr Proposed translation.
622 * \return Snapped translation, if a snap occurred, and a flag indicating whether a snap occurred.
623 */
625 Inkscape::SnappedPoint SnapManager::freeSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
626 std::vector<std::pair<Geom::Point, int> > const &p,
627 Geom::Point const &pointer,
628 Geom::Point const &tr) const
629 {
630 if (p.size() == 1) {
631 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false), (p.at(0)).second));
632 }
634 return _snapTransformed(point_type, p, pointer, false, Geom::Point(0,0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
635 }
638 /**
639 * Try to snap a list of points to any interested snappers after they have undergone a
640 * translation. A snap will only occur along a line described by a
641 * Inkscape::Snapper::ConstraintLine.
642 *
643 * \param point_type Type of points.
644 * \param p Points.
645 * \param constraint Constraint line.
646 * \param tr Proposed translation.
647 * \return Snapped translation, if a snap occurred, and a flag indicating whether a snap occurred.
648 */
650 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
651 std::vector<std::pair<Geom::Point, int> > const &p,
652 Geom::Point const &pointer,
653 Inkscape::Snapper::ConstraintLine const &constraint,
654 Geom::Point const &tr) const
655 {
656 if (p.size() == 1) {
657 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false), (p.at(0)).second));
658 }
660 return _snapTransformed(point_type, p, pointer, true, constraint, TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
661 }
664 /**
665 * Try to snap a list of points to any interested snappers after they have undergone
666 * a scale.
667 *
668 * \param point_type Type of points.
669 * \param p Points.
670 * \param s Proposed scale.
671 * \param o Origin of proposed scale.
672 * \return Snapped scale, if a snap occurred, and a flag indicating whether a snap occurred.
673 */
675 Inkscape::SnappedPoint SnapManager::freeSnapScale(Inkscape::SnapPreferences::PointType point_type,
676 std::vector<std::pair<Geom::Point, int> > const &p,
677 Geom::Point const &pointer,
678 Geom::Scale const &s,
679 Geom::Point const &o) const
680 {
681 if (p.size() == 1) {
682 _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));
683 }
685 return _snapTransformed(point_type, p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
686 }
689 /**
690 * Try to snap a list of points to any interested snappers after they have undergone
691 * a scale. A snap will only occur along a line described by a
692 * Inkscape::Snapper::ConstraintLine.
693 *
694 * \param point_type Type of points.
695 * \param p Points.
696 * \param s Proposed scale.
697 * \param o Origin of proposed scale.
698 * \return Snapped scale, if a snap occurred, and a flag indicating whether a snap occurred.
699 */
701 Inkscape::SnappedPoint SnapManager::constrainedSnapScale(Inkscape::SnapPreferences::PointType point_type,
702 std::vector<std::pair<Geom::Point, int> > const &p,
703 Geom::Point const &pointer,
704 Geom::Scale const &s,
705 Geom::Point const &o) const
706 {
707 // When constrained scaling, only uniform scaling is supported.
708 if (p.size() == 1) {
709 _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));
710 }
712 return _snapTransformed(point_type, p, pointer, true, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
713 }
716 /**
717 * Try to snap a list of points to any interested snappers after they have undergone
718 * a stretch.
719 *
720 * \param point_type Type of points.
721 * \param p Points.
722 * \param s Proposed stretch.
723 * \param o Origin of proposed stretch.
724 * \param d Dimension in which to apply proposed stretch.
725 * \param u true if the stretch should be uniform (ie to be applied equally in both dimensions)
726 * \return Snapped stretch, if a snap occurred, and a flag indicating whether a snap occurred.
727 */
729 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(Inkscape::SnapPreferences::PointType point_type,
730 std::vector<std::pair<Geom::Point, int> > const &p,
731 Geom::Point const &pointer,
732 Geom::Coord const &s,
733 Geom::Point const &o,
734 Geom::Dim2 d,
735 bool u) const
736 {
737 if (p.size() == 1) {
738 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), STRETCH, Geom::Point(s, s), o, d, u), (p.at(0)).second));
739 }
741 return _snapTransformed(point_type, p, pointer, true, Geom::Point(0,0), STRETCH, Geom::Point(s, s), o, d, u);
742 }
745 /**
746 * Try to snap a list of points to any interested snappers after they have undergone
747 * a skew.
748 *
749 * \param point_type Type of points.
750 * \param p Points.
751 * \param s Proposed skew.
752 * \param o Origin of proposed skew.
753 * \param d Dimension in which to apply proposed skew.
754 * \return Snapped skew, if a snap occurred, and a flag indicating whether a snap occurred.
755 */
757 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(Inkscape::SnapPreferences::PointType point_type,
758 std::vector<std::pair<Geom::Point, int> > const &p,
759 Geom::Point const &pointer,
760 Inkscape::Snapper::ConstraintLine const &constraint,
761 Geom::Point const &s,
762 Geom::Point const &o,
763 Geom::Dim2 d) const
764 {
765 // "s" contains skew factor in s[0], and scale factor in s[1]
767 // Snapping the nodes of the boundingbox of a selection that is being transformed, will only work if
768 // the transformation of the bounding box is equal to the transformation of the individual nodes. This is
769 // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
770 // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
771 // of bounding boxes is not allowed here.
772 g_assert(!(point_type & Inkscape::SnapPreferences::SNAPPOINT_BBOX));
774 if (p.size() == 1) {
775 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), SKEW, s, o, d, false), (p.at(0)).second));
776 }
778 return _snapTransformed(point_type, p, pointer, true, constraint, SKEW, s, o, d, false);
779 }
781 Inkscape::SnappedPoint SnapManager::findBestSnap(Geom::Point const &p, Inkscape::SnapSourceType const source_type, SnappedConstraints &sc, bool constrained) const
782 {
784 /*
785 std::cout << "Type and number of snapped constraints: " << std::endl;
786 std::cout << " Points : " << sc.points.size() << std::endl;
787 std::cout << " Lines : " << sc.lines.size() << std::endl;
788 std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
789 std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
790 std::cout << " Curves : " << sc.curves.size()<< std::endl;
791 */
793 // Store all snappoints
794 std::list<Inkscape::SnappedPoint> sp_list;
796 // search for the closest snapped point
797 Inkscape::SnappedPoint closestPoint;
798 if (getClosestSP(sc.points, closestPoint)) {
799 sp_list.push_back(closestPoint);
800 }
802 // search for the closest snapped curve
803 Inkscape::SnappedCurve closestCurve;
804 if (getClosestCurve(sc.curves, closestCurve)) {
805 sp_list.push_back(Inkscape::SnappedPoint(closestCurve));
806 }
808 if (snapprefs.getSnapIntersectionCS()) {
809 // search for the closest snapped intersection of curves
810 Inkscape::SnappedPoint closestCurvesIntersection;
811 if (getClosestIntersectionCS(sc.curves, p, closestCurvesIntersection, _desktop->dt2doc())) {
812 closestCurvesIntersection.setSource(source_type);
813 sp_list.push_back(closestCurvesIntersection);
814 }
815 }
817 // search for the closest snapped grid line
818 Inkscape::SnappedLine closestGridLine;
819 if (getClosestSL(sc.grid_lines, closestGridLine)) {
820 sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
821 }
823 // search for the closest snapped guide line
824 Inkscape::SnappedLine closestGuideLine;
825 if (getClosestSL(sc.guide_lines, closestGuideLine)) {
826 sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
827 }
829 // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
830 // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
832 // When doing a constrained snap however, we're already at an intersection of the constrained line and
833 // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
834 // no need to look for additional intersections
835 if (!constrained) {
836 // search for the closest snapped intersection of grid lines
837 Inkscape::SnappedPoint closestGridPoint;
838 if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
839 closestGridPoint.setSource(source_type);
840 closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
841 sp_list.push_back(closestGridPoint);
842 }
844 // search for the closest snapped intersection of guide lines
845 Inkscape::SnappedPoint closestGuidePoint;
846 if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
847 closestGuidePoint.setSource(source_type);
848 closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
849 sp_list.push_back(closestGuidePoint);
850 }
852 // search for the closest snapped intersection of grid with guide lines
853 if (snapprefs.getSnapIntersectionGG()) {
854 Inkscape::SnappedPoint closestGridGuidePoint;
855 if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
856 closestGridGuidePoint.setSource(source_type);
857 closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
858 sp_list.push_back(closestGridGuidePoint);
859 }
860 }
861 }
863 // now let's see which snapped point gets a thumbs up
864 Inkscape::SnappedPoint bestSnappedPoint = Inkscape::SnappedPoint(p, Inkscape::SNAPSOURCE_UNDEFINED, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
865 // std::cout << "Finding the best snap..." << std::endl;
866 for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
867 // first find out if this snapped point is within snapping range
868 // std::cout << "sp = " << from_2geom((*i).getPoint());
869 if ((*i).getSnapDistance() <= (*i).getTolerance()) {
870 // if it's the first point, or if it is closer than the best snapped point so far
871 if (i == sp_list.begin() || bestSnappedPoint.isOtherSnapBetter(*i, false)) {
872 // then prefer this point over the previous one
873 bestSnappedPoint = *i;
874 }
875 }
876 // std::cout << std::endl;
877 }
879 // Update the snap indicator, if requested
880 if (_snapindicator) {
881 if (bestSnappedPoint.getSnapped()) {
882 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
883 } else {
884 _desktop->snapindicator->remove_snaptarget();
885 }
886 }
888 // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl;
889 return bestSnappedPoint;
890 }
892 void SnapManager::setup(SPDesktop const *desktop,
893 bool snapindicator,
894 SPItem const *item_to_ignore,
895 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
896 SPGuide *guide_to_ignore)
897 {
898 g_assert(desktop != NULL);
899 _item_to_ignore = item_to_ignore;
900 _items_to_ignore = NULL;
901 _desktop = desktop;
902 _snapindicator = snapindicator;
903 _unselected_nodes = unselected_nodes;
904 _guide_to_ignore = guide_to_ignore;
905 }
907 void SnapManager::setup(SPDesktop const *desktop,
908 bool snapindicator,
909 std::vector<SPItem const *> &items_to_ignore,
910 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
911 SPGuide *guide_to_ignore)
912 {
913 g_assert(desktop != NULL);
914 _item_to_ignore = NULL;
915 _items_to_ignore = &items_to_ignore;
916 _desktop = desktop;
917 _snapindicator = snapindicator;
918 _unselected_nodes = unselected_nodes;
919 _guide_to_ignore = guide_to_ignore;
920 }
922 SPDocument *SnapManager::getDocument() const
923 {
924 return _named_view->document;
925 }
927 Geom::Point SnapManager::_transformPoint(std::pair<Geom::Point, int> const &p,
928 Transformation const transformation_type,
929 Geom::Point const &transformation,
930 Geom::Point const &origin,
931 Geom::Dim2 const dim,
932 bool const uniform) const
933 {
934 /* Work out the transformed version of this point */
935 Geom::Point transformed;
936 switch (transformation_type) {
937 case TRANSLATION:
938 transformed = p.first + transformation;
939 break;
940 case SCALE:
941 transformed = (p.first - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
942 break;
943 case STRETCH:
944 {
945 Geom::Scale s(1, 1);
946 if (uniform)
947 s[Geom::X] = s[Geom::Y] = transformation[dim];
948 else {
949 s[dim] = transformation[dim];
950 s[1 - dim] = 1;
951 }
952 transformed = ((p.first - origin) * s) + origin;
953 break;
954 }
955 case SKEW:
956 // Apply the skew factor
957 transformed[dim] = (p.first)[dim] + transformation[0] * ((p.first)[1 - dim] - origin[1 - dim]);
958 // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
959 // Apply that scale factor here
960 transformed[1-dim] = (p.first - origin)[1 - dim] * transformation[1] + origin[1 - dim];
961 break;
962 default:
963 g_assert_not_reached();
964 }
966 return transformed;
967 }
969 void SnapManager::_displaySnapsource(Inkscape::SnapPreferences::PointType point_type, std::pair<Geom::Point, int> const &p) const {
971 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
972 if (prefs->getBool("/options/snapclosestonly/value")) {
973 bool p_is_a_node = point_type & Inkscape::SnapPreferences::SNAPPOINT_NODE;
974 bool p_is_a_bbox = point_type & Inkscape::SnapPreferences::SNAPPOINT_BBOX;
975 if (snapprefs.getSnapEnabledGlobally() && ((p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) {
976 _desktop->snapindicator->set_new_snapsource(p);
977 } else {
978 _desktop->snapindicator->remove_snapsource();
979 }
980 }
981 }
983 /*
984 Local Variables:
985 mode:c++
986 c-file-style:"stroustrup"
987 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
988 indent-tabs-mode:nil
989 fill-column:99
990 End:
991 */
992 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :