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 using std::vector;
37 /**
38 * Construct a SnapManager for a SPNamedView.
39 *
40 * \param v `Owning' SPNamedView.
41 */
43 SnapManager::SnapManager(SPNamedView const *v) :
44 guide(this, 0),
45 object(this, 0),
46 snapprefs(),
47 _named_view(v)
48 {
49 }
51 /**
52 * \return List of snappers that we use.
53 */
54 SnapManager::SnapperList
55 SnapManager::getSnappers() const
56 {
57 SnapManager::SnapperList s;
58 s.push_back(&guide);
59 s.push_back(&object);
61 SnapManager::SnapperList gs = getGridSnappers();
62 s.splice(s.begin(), gs);
64 return s;
65 }
67 /**
68 * \return List of gridsnappers that we use.
69 */
70 SnapManager::SnapperList
71 SnapManager::getGridSnappers() const
72 {
73 SnapperList s;
75 //FIXME: this code should actually do this: add new grid snappers that are active for this desktop. now it just adds all gridsnappers
76 if (_desktop && _desktop->gridsEnabled() && snapprefs.getSnapToGrids()) {
77 for ( GSList const *l = _named_view->grids; l != NULL; l = l->next) {
78 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
79 s.push_back(grid->snapper);
80 }
81 }
83 return s;
84 }
86 /**
87 * \return true if one of the snappers will try to snap something.
88 */
90 bool SnapManager::someSnapperMightSnap() const
91 {
92 if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) {
93 return false;
94 }
96 SnapperList const s = getSnappers();
97 SnapperList::const_iterator i = s.begin();
98 while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
99 i++;
100 }
102 return (i != s.end());
103 }
105 /**
106 * \return true if one of the snappers will try to snap something.
107 */
109 bool SnapManager::gridSnapperMightSnap() const
110 {
111 if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) {
112 return false;
113 }
115 SnapperList const s = getGridSnappers();
116 SnapperList::const_iterator i = s.begin();
117 while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) {
118 i++;
119 }
121 return (i != s.end());
122 }
124 /**
125 * Try to snap a point to any of the specified snappers.
126 *
127 * \param point_type Type of point.
128 * \param p Point.
129 * \param first_point If true then this point is the first one from a whole bunch of points
130 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
131 * \param snappers List of snappers to try to snap to
132 * \return Snapped point.
133 */
135 void SnapManager::freeSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
136 Geom::Point &p,
137 Inkscape::SnapSourceType const source_type,
138 bool first_point,
139 Geom::OptRect const &bbox_to_snap) const
140 {
141 Inkscape::SnappedPoint const s = freeSnap(point_type, p, source_type, first_point, bbox_to_snap);
142 s.getPoint(p);
143 }
146 /**
147 * Try to snap a point to any of the specified snappers.
148 *
149 * \param point_type Type of point.
150 * \param p Point.
151 * \param first_point If true then this point is the first one from a whole bunch of points
152 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
153 * \param snappers List of snappers to try to snap to
154 * \return Snapped point.
155 */
157 Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::SnapPreferences::PointType point_type,
158 Geom::Point const &p,
159 Inkscape::SnapSourceType const &source_type,
160 bool first_point,
161 Geom::OptRect const &bbox_to_snap) const
162 {
163 if (_desktop->canvas->context_snap_delay_active == false) {
164 g_warning("context_snap_delay_active has not been set to true by the current context. Please report this!");
165 // When the context goes into dragging-mode, then Inkscape should call this: sp_canvas_set_snap_delay_active(desktop->canvas, true);
166 }
168 if (!someSnapperMightSnap()) {
169 return Inkscape::SnappedPoint(p, source_type, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
170 }
172 std::vector<SPItem const *> *items_to_ignore;
173 if (_item_to_ignore) { // If we have only a single item to ignore
174 // then build a list containing this single item;
175 // This single-item list will prevail over any other _items_to_ignore list, should that exist
176 items_to_ignore = new std::vector<SPItem const *>;
177 items_to_ignore->push_back(_item_to_ignore);
178 } else {
179 items_to_ignore = _items_to_ignore;
180 }
182 SnappedConstraints sc;
183 SnapperList const snappers = getSnappers();
185 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
186 (*i)->freeSnap(sc, point_type, p, source_type, first_point, bbox_to_snap, items_to_ignore, _unselected_nodes);
187 }
189 if (_item_to_ignore) {
190 delete items_to_ignore;
191 }
193 return findBestSnap(p, source_type, sc, false);
194 }
196 // When pasting, we would like to snap to the grid. Problem is that we don't know which nodes were
197 // aligned to the grid at the time of copying, so we don't know which nodes to snap. If we'd snap an
198 // unaligned node to the grid, previously aligned nodes would become unaligned. That's undesirable.
199 // Instead we will make sure that the offset between the source and the copy is a multiple of the grid
200 // pitch. If the source was aligned, then the copy will therefore also be aligned
201 // PS: Whether we really find a multiple also depends on the snapping range!
202 Geom::Point SnapManager::multipleOfGridPitch(Geom::Point const &t) const
203 {
204 if (!snapprefs.getSnapEnabledGlobally()) // No need to check for snapprefs.getSnapPostponedGlobally() here
205 return t;
207 //FIXME: this code should actually do this: add new grid snappers that are active for this desktop. now it just adds all gridsnappers
209 if (_desktop && _desktop->gridsEnabled()) {
210 bool success = false;
211 Geom::Point nearest_multiple;
212 Geom::Coord nearest_distance = NR_HUGE;
214 // It will snap to the grid for which we find the closest snap. This might be a different
215 // grid than to which the objects were initially aligned. I don't see an easy way to fix
216 // this, so when using multiple grids one can get unexpected results
218 // Cannot use getGridSnappers() because we need both the grids AND their snappers
219 // Therefore we iterate through all grids manually
220 for (GSList const *l = _named_view->grids; l != NULL; l = l->next) {
221 Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data;
222 const Inkscape::Snapper* snapper = grid->snapper;
223 if (snapper && snapper->ThisSnapperMightSnap()) {
224 // To find the nearest multiple of the grid pitch for a given translation t, we
225 // will use the grid snapper. Simply snapping the value t to the grid will do, but
226 // only if the origin of the grid is at (0,0). If it's not then compensate for this
227 // in the translation t
228 Geom::Point const t_offset = t + grid->origin;
229 SnappedConstraints sc;
230 // Only the first three parameters are being used for grid snappers
231 snapper->freeSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_NODE, t_offset, Inkscape::SNAPSOURCE_UNDEFINED, TRUE, Geom::OptRect(), NULL, NULL);
232 // Find the best snap for this grid, including intersections of the grid-lines
233 Inkscape::SnappedPoint s = findBestSnap(t_offset, Inkscape::SNAPSOURCE_UNDEFINED, sc, false);
234 if (s.getSnapped() && (s.getSnapDistance() < nearest_distance)) {
235 // use getSnapDistance() instead of getWeightedDistance() here because the pointer's position
236 // doesn't tell us anything about which node to snap
237 success = true;
238 nearest_multiple = s.getPoint() - to_2geom(grid->origin);
239 nearest_distance = s.getSnapDistance();
240 }
241 }
242 }
244 if (success)
245 return nearest_multiple;
246 }
248 return t;
249 }
251 /**
252 * Try to snap a point to any interested snappers. A snap will only occur along
253 * a line described by a Inkscape::Snapper::ConstraintLine.
254 *
255 * \param point_type Type of point.
256 * \param p Point.
257 * \param first_point If true then this point is the first one from a whole bunch of points
258 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
259 * \param constraint Constraint line.
260 * \return Snapped point.
261 */
263 void SnapManager::constrainedSnapReturnByRef(Inkscape::SnapPreferences::PointType point_type,
264 Geom::Point &p,
265 Inkscape::SnapSourceType const source_type,
266 Inkscape::Snapper::ConstraintLine const &constraint,
267 bool const snap_projection,
268 bool first_point,
269 Geom::OptRect const &bbox_to_snap) const
270 {
271 Inkscape::SnappedPoint const s = constrainedSnap(point_type, p, source_type, constraint, snap_projection, first_point, bbox_to_snap);
272 s.getPoint(p);
273 }
276 /**
277 * Try to snap a point to any interested snappers. A snap will only occur along
278 * a line described by a Inkscape::Snapper::ConstraintLine.
279 *
280 * \param point_type Type of point.
281 * \param p Point.
282 * \param first_point If true then this point is the first one from a whole bunch of points
283 * \param points_to_snap The whole bunch of points, all from the same selection and having the same transformation
284 * \param constraint Constraint line.
285 * \return Snapped point.
286 */
288 Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::SnapPreferences::PointType point_type,
289 Geom::Point const &p,
290 Inkscape::SnapSourceType const &source_type,
291 Inkscape::Snapper::ConstraintLine const &constraint,
292 bool snap_projection,
293 bool first_point,
294 Geom::OptRect const &bbox_to_snap) const
295 {
296 if (_desktop->canvas->context_snap_delay_active == false) {
297 g_warning("context_snap_delay_active has not been set to true by the current context. Please report this!");
298 // When the context goes into dragging-mode, then Inkscape should call this: sp_canvas_set_snap_delay_active(desktop->canvas, true);
299 }
301 if (!someSnapperMightSnap()) {
302 return Inkscape::SnappedPoint(p, source_type, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
303 }
305 std::vector<SPItem const *> *items_to_ignore;
306 if (_item_to_ignore) { // If we have only a single item to ignore
307 // then build a list containing this single item;
308 // This single-item list will prevail over any other _items_to_ignore list, should that exist
309 items_to_ignore = new std::vector<SPItem const *>;
310 items_to_ignore->push_back(_item_to_ignore);
311 } else {
312 items_to_ignore = _items_to_ignore;
313 }
315 Geom::Point pp = constraint.projection(p);
317 SnappedConstraints sc;
318 SnapperList const snappers = getSnappers();
319 for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) {
320 (*i)->constrainedSnap(sc, point_type, pp, source_type, first_point, bbox_to_snap, constraint, items_to_ignore);
321 }
323 if (_item_to_ignore) {
324 delete items_to_ignore;
325 }
327 return findBestSnap(p, source_type, sc, true);
328 }
330 void SnapManager::guideSnap(Geom::Point &p, Geom::Point const &guide_normal) const
331 {
332 // This method is used to snap a guide to nodes or to other guides, while dragging the guide around. Will not snap to grids!
334 if (_desktop->canvas->context_snap_delay_active == false) {
335 g_warning("context_snap_delay_active has not been set to true by the current context. Please report this!");
336 // When the context goes into dragging-mode, then Inkscape should call this: sp_canvas_set_snap_delay_active(desktop->canvas, true);
337 }
339 if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) {
340 return;
341 }
343 if (!(object.GuidesMightSnap() || snapprefs.getSnapToGuides())) {
344 return;
345 }
347 // Snap to nodes
348 SnappedConstraints sc;
349 if (object.GuidesMightSnap()) {
350 object.guideSnap(sc, p, guide_normal);
351 }
353 // Snap to guides
354 if (snapprefs.getSnapToGuides()) {
355 guide.freeSnap(sc, Inkscape::SnapPreferences::SNAPPOINT_GUIDE, p, Inkscape::SNAPSOURCE_GUIDE, true, Geom::OptRect(), NULL, NULL);
356 }
358 // We won't snap to grids, what's the use?
360 Inkscape::SnappedPoint const s = findBestSnap(p, Inkscape::SNAPSOURCE_GUIDE, sc, false);
361 s.getPoint(p);
362 }
365 /**
366 * Main internal snapping method, which is called by the other, friendlier, public
367 * methods. It's a bit hairy as it has lots of parameters, but it saves on a lot
368 * of duplicated code.
369 *
370 * \param type Type of points being snapped.
371 * \param points List of points to snap (i.e. untransformed).
372 * \param pointer Location of the mouse pointer, at the time when dragging started (i.e. "untransformed")
373 * \param constrained true if the snap is constrained.
374 * \param constraint Constraint line to use, if `constrained' is true, otherwise undefined.
375 * \param transformation_type Type of transformation to apply to points before trying to snap them.
376 * \param transformation Description of the transformation; details depend on the type.
377 * \param origin Origin of the transformation, if applicable.
378 * \param dim Dimension of the transformation, if applicable.
379 * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling.
380 */
382 Inkscape::SnappedPoint SnapManager::_snapTransformed(
383 Inkscape::SnapPreferences::PointType type,
384 std::vector<std::pair<Geom::Point, int> > const &points,
385 Geom::Point const &pointer,
386 bool constrained,
387 Inkscape::Snapper::ConstraintLine const &constraint,
388 Transformation transformation_type,
389 Geom::Point const &transformation,
390 Geom::Point const &origin,
391 Geom::Dim2 dim,
392 bool uniform) const
393 {
394 /* We have a list of points, which we are proposing to transform in some way. We need to see
395 ** if any of these points, when transformed, snap to anything. If they do, we return the
396 ** appropriate transformation with `true'; otherwise we return the original scale with `false'.
397 */
399 /* Quick check to see if we have any snappers that are enabled
400 ** Also used to globally disable all snapping
401 */
402 if (someSnapperMightSnap() == false) {
403 return Inkscape::SnappedPoint();
404 }
406 std::vector<std::pair<Geom::Point, int> > transformed_points;
407 Geom::Rect bbox;
409 for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = points.begin(); i != points.end(); i++) {
411 /* Work out the transformed version of this point */
412 Geom::Point transformed = _transformPoint(*i, transformation_type, transformation, origin, dim, uniform);
414 // add the current transformed point to the box hulling all transformed points
415 if (i == points.begin()) {
416 bbox = Geom::Rect(transformed, transformed);
417 } else {
418 bbox.expandTo(transformed);
419 }
421 transformed_points.push_back(std::make_pair(transformed, (*i).second));
422 }
424 /* The current best transformation */
425 Geom::Point best_transformation = transformation;
427 /* The current best metric for the best transformation; lower is better, NR_HUGE
428 ** means that we haven't snapped anything.
429 */
430 Geom::Point best_scale_metric(NR_HUGE, NR_HUGE);
431 Inkscape::SnappedPoint best_snapped_point;
432 g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point
433 g_assert(best_snapped_point.getAtIntersection() == false);
435 std::vector<std::pair<Geom::Point, int> >::const_iterator j = transformed_points.begin();
437 // std::cout << std::endl;
438 for (std::vector<std::pair<Geom::Point, int> >::const_iterator i = points.begin(); i != points.end(); i++) {
440 /* Snap it */
441 Inkscape::SnappedPoint snapped_point;
442 Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint;
443 Geom::Point const b = ((*i).first - origin); // vector to original point
445 if (constrained) {
446 if ((transformation_type == SCALE || transformation_type == STRETCH) && uniform) {
447 // When uniformly scaling, each point will have its own unique constraint line,
448 // running from the scaling origin to the original untransformed point. We will
449 // calculate that line here
450 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, b);
451 } else if (transformation_type == STRETCH) { // when non-uniform stretching {
452 dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i).first, component_vectors[dim]);
453 } else if (transformation_type == TRANSLATION) {
454 // When doing a constrained translation, all points will move in the same direction, i.e.
455 // either horizontally or vertically. The lines along which they move are therefore all
456 // parallel, but might not be colinear. Therefore we will have to set the point through
457 // which the constraint-line runs here, for each point individually.
458 dedicated_constraint.setPoint((*i).first);
459 } // else: leave the original constraint, e.g. for skewing
460 if (transformation_type == SCALE && !uniform) {
461 g_warning("Non-uniform constrained scaling is not supported!");
462 }
463 snapped_point = constrainedSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), dedicated_constraint, false, i == points.begin(), bbox);
464 } else {
465 bool const c1 = fabs(b[Geom::X]) < 1e-6;
466 bool const c2 = fabs(b[Geom::Y]) < 1e-6;
467 if (transformation_type == SCALE && (c1 || c2) && !(c1 && c2)) {
468 // When scaling, a point aligned either horizontally or vertically with the origin can only
469 // move in that specific direction; therefore it should only snap in that direction, otherwise
470 // we will get snapped points with an invalid transformation
471 dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, component_vectors[c1]);
472 snapped_point = constrainedSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), dedicated_constraint, false, i == points.begin(), bbox);
473 } else {
474 snapped_point = freeSnap(type, (*j).first, static_cast<Inkscape::SnapSourceType>((*j).second), i == points.begin(), bbox);
475 }
476 }
477 // std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl;
478 snapped_point.setPointerDistance(Geom::L2(pointer - (*i).first));
480 Geom::Point result;
481 Geom::Point scale_metric(NR_HUGE, NR_HUGE);
483 if (snapped_point.getSnapped()) {
484 /* We snapped. Find the transformation that describes where the snapped point has
485 ** ended up, and also the metric for this transformation.
486 */
487 Geom::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point
488 //Geom::Point const b = (*i - origin); // vector to original point
490 switch (transformation_type) {
491 case TRANSLATION:
492 result = snapped_point.getPoint() - (*i).first;
493 /* Consider the case in which a box is almost aligned with a grid in both
494 * horizontal and vertical directions. The distance to the intersection of
495 * the grid lines will always be larger then the distance to a single grid
496 * line. If we prefer snapping to an intersection instead of to a single
497 * grid line, then we cannot use "metric = Geom::L2(result)". Therefore the
498 * snapped distance will be used as a metric. Please note that the snapped
499 * distance is defined as the distance to the nearest line of the intersection,
500 * and not to the intersection itself!
501 */
502 // Only for translations, the relevant metric will be the real snapped distance,
503 // so we don't have to do anything special here
504 break;
505 case SCALE:
506 {
507 result = Geom::Point(NR_HUGE, NR_HUGE);
508 // If this point *i is horizontally or vertically aligned with
509 // the origin of the scaling, then it will scale purely in X or Y
510 // We can therefore only calculate the scaling in this direction
511 // and the scaling factor for the other direction should remain
512 // untouched (unless scaling is uniform ofcourse)
513 for (int index = 0; index < 2; index++) {
514 if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction
515 if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction
516 result[index] = a[index] / b[index]; // then calculate it!
517 }
518 // we might leave result[1-index] = NR_HUGE
519 // if scaling didn't occur in the other direction
520 }
521 }
522 // Compare the resulting scaling with the desired scaling
523 scale_metric = result - transformation; // One or both of its components might be NR_HUGE
524 break;
525 }
526 case STRETCH:
527 result = Geom::Point(NR_HUGE, NR_HUGE);
528 if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point
529 result[dim] = a[dim] / b[dim];
530 result[1-dim] = uniform ? result[dim] : 1;
531 } else { // STRETCHING might occur for this point, but only when the stretching is uniform
532 if (uniform && fabs(b[1-dim]) > 1e-6) {
533 result[1-dim] = a[1-dim] / b[1-dim];
534 result[dim] = result[1-dim];
535 }
536 }
537 // Store the metric for this transformation as a virtual distance
538 snapped_point.setSnapDistance(std::abs(result[dim] - transformation[dim]));
539 snapped_point.setSecondSnapDistance(NR_HUGE);
540 break;
541 case SKEW:
542 result[0] = (snapped_point.getPoint()[dim] - ((*i).first)[dim]) / (((*i).first)[1 - dim] - origin[1 - dim]); // skew factor
543 result[1] = transformation[1]; // scale factor
544 // Store the metric for this transformation as a virtual distance
545 snapped_point.setSnapDistance(std::abs(result[0] - transformation[0]));
546 snapped_point.setSecondSnapDistance(NR_HUGE);
547 break;
548 default:
549 g_assert_not_reached();
550 }
552 // When scaling, we're considering the best transformation in each direction separately. We will have a metric in each
553 // direction, whereas for all other transformation we only a single one-dimensional metric. That's why we need to handle
554 // the scaling metric differently
555 if (transformation_type == SCALE) {
556 for (int index = 0; index < 2; index++) {
557 if (fabs(scale_metric[index]) < fabs(best_scale_metric[index])) {
558 best_transformation[index] = result[index];
559 best_scale_metric[index] = fabs(scale_metric[index]);
560 // When scaling, we're considering the best transformation in each direction separately
561 // Therefore two different snapped points might together make a single best transformation
562 // We will however return only a single snapped point (e.g. to display the snapping indicator)
563 best_snapped_point = snapped_point;
564 // std::cout << "SEL ";
565 } // else { std::cout << " ";}
566 }
567 if (uniform) {
568 if (best_scale_metric[0] < best_scale_metric[1]) {
569 best_transformation[1] = best_transformation[0];
570 best_scale_metric[1] = best_scale_metric[0];
571 } else {
572 best_transformation[0] = best_transformation[1];
573 best_scale_metric[0] = best_scale_metric[1];
574 }
575 }
576 } else { // For all transformations other than scaling
577 if (best_snapped_point.isOtherSnapBetter(snapped_point, true)) {
578 best_transformation = result;
579 best_snapped_point = snapped_point;
580 }
581 }
582 }
584 j++;
585 }
587 Geom::Coord best_metric;
588 if (transformation_type == SCALE) {
589 // When scaling, don't ever exit with one of scaling components set to NR_HUGE
590 for (int index = 0; index < 2; index++) {
591 if (best_transformation[index] == NR_HUGE) {
592 if (uniform && best_transformation[1-index] < NR_HUGE) {
593 best_transformation[index] = best_transformation[1-index];
594 } else {
595 best_transformation[index] = transformation[index];
596 }
597 }
598 }
599 best_metric = std::min(best_scale_metric[0], best_scale_metric[1]);
600 } else { // For all transformations other than scaling
601 best_metric = best_snapped_point.getSnapDistance();
602 }
604 best_snapped_point.setTransformation(best_transformation);
605 // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors
606 // These rounding errors might be caused by NRRects, see bug #1584301
607 best_snapped_point.setSnapDistance(best_metric < 1e6 ? best_metric : NR_HUGE);
608 return best_snapped_point;
609 }
612 /**
613 * Try to snap a list of points to any interested snappers after they have undergone
614 * a translation.
615 *
616 * \param point_type Type of points.
617 * \param p Points.
618 * \param tr Proposed translation.
619 * \return Snapped translation, if a snap occurred, and a flag indicating whether a snap occurred.
620 */
622 Inkscape::SnappedPoint SnapManager::freeSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
623 std::vector<std::pair<Geom::Point, int> > const &p,
624 Geom::Point const &pointer,
625 Geom::Point const &tr) const
626 {
627 if (p.size() == 1) {
628 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false), (p.at(0)).second));
629 }
631 return _snapTransformed(point_type, p, pointer, false, Geom::Point(0,0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
632 }
635 /**
636 * Try to snap a list of points to any interested snappers after they have undergone a
637 * translation. A snap will only occur along a line described by a
638 * Inkscape::Snapper::ConstraintLine.
639 *
640 * \param point_type Type of points.
641 * \param p Points.
642 * \param constraint Constraint line.
643 * \param tr Proposed translation.
644 * \return Snapped translation, if a snap occurred, and a flag indicating whether a snap occurred.
645 */
647 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslation(Inkscape::SnapPreferences::PointType point_type,
648 std::vector<std::pair<Geom::Point, int> > const &p,
649 Geom::Point const &pointer,
650 Inkscape::Snapper::ConstraintLine const &constraint,
651 Geom::Point const &tr) const
652 {
653 if (p.size() == 1) {
654 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false), (p.at(0)).second));
655 }
657 return _snapTransformed(point_type, p, pointer, true, constraint, TRANSLATION, tr, Geom::Point(0,0), Geom::X, false);
658 }
661 /**
662 * Try to snap a list of points to any interested snappers after they have undergone
663 * a scale.
664 *
665 * \param point_type Type of points.
666 * \param p Points.
667 * \param s Proposed scale.
668 * \param o Origin of proposed scale.
669 * \return Snapped scale, if a snap occurred, and a flag indicating whether a snap occurred.
670 */
672 Inkscape::SnappedPoint SnapManager::freeSnapScale(Inkscape::SnapPreferences::PointType point_type,
673 std::vector<std::pair<Geom::Point, int> > const &p,
674 Geom::Point const &pointer,
675 Geom::Scale const &s,
676 Geom::Point const &o) const
677 {
678 if (p.size() == 1) {
679 _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));
680 }
682 return _snapTransformed(point_type, p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false);
683 }
686 /**
687 * Try to snap a list of points to any interested snappers after they have undergone
688 * a scale. A snap will only occur along a line described by a
689 * Inkscape::Snapper::ConstraintLine.
690 *
691 * \param point_type Type of points.
692 * \param p Points.
693 * \param s Proposed scale.
694 * \param o Origin of proposed scale.
695 * \return Snapped scale, if a snap occurred, and a flag indicating whether a snap occurred.
696 */
698 Inkscape::SnappedPoint SnapManager::constrainedSnapScale(Inkscape::SnapPreferences::PointType point_type,
699 std::vector<std::pair<Geom::Point, int> > const &p,
700 Geom::Point const &pointer,
701 Geom::Scale const &s,
702 Geom::Point const &o) const
703 {
704 // When constrained scaling, only uniform scaling is supported.
705 if (p.size() == 1) {
706 _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));
707 }
709 return _snapTransformed(point_type, p, pointer, true, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true);
710 }
713 /**
714 * Try to snap a list of points to any interested snappers after they have undergone
715 * a stretch.
716 *
717 * \param point_type Type of points.
718 * \param p Points.
719 * \param s Proposed stretch.
720 * \param o Origin of proposed stretch.
721 * \param d Dimension in which to apply proposed stretch.
722 * \param u true if the stretch should be uniform (ie to be applied equally in both dimensions)
723 * \return Snapped stretch, if a snap occurred, and a flag indicating whether a snap occurred.
724 */
726 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(Inkscape::SnapPreferences::PointType point_type,
727 std::vector<std::pair<Geom::Point, int> > const &p,
728 Geom::Point const &pointer,
729 Geom::Coord const &s,
730 Geom::Point const &o,
731 Geom::Dim2 d,
732 bool u) const
733 {
734 if (p.size() == 1) {
735 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), STRETCH, Geom::Point(s, s), o, d, u), (p.at(0)).second));
736 }
738 return _snapTransformed(point_type, p, pointer, true, Geom::Point(0,0), STRETCH, Geom::Point(s, s), o, d, u);
739 }
742 /**
743 * Try to snap a list of points to any interested snappers after they have undergone
744 * a skew.
745 *
746 * \param point_type Type of points.
747 * \param p Points.
748 * \param s Proposed skew.
749 * \param o Origin of proposed skew.
750 * \param d Dimension in which to apply proposed skew.
751 * \return Snapped skew, if a snap occurred, and a flag indicating whether a snap occurred.
752 */
754 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(Inkscape::SnapPreferences::PointType point_type,
755 std::vector<std::pair<Geom::Point, int> > const &p,
756 Geom::Point const &pointer,
757 Inkscape::Snapper::ConstraintLine const &constraint,
758 Geom::Point const &s,
759 Geom::Point const &o,
760 Geom::Dim2 d) const
761 {
762 // "s" contains skew factor in s[0], and scale factor in s[1]
764 // Snapping the nodes of the boundingbox of a selection that is being transformed, will only work if
765 // the transformation of the bounding box is equal to the transformation of the individual nodes. This is
766 // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew,
767 // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping
768 // of bounding boxes is not allowed here.
769 g_assert(!(point_type & Inkscape::SnapPreferences::SNAPPOINT_BBOX));
771 if (p.size() == 1) {
772 _displaySnapsource(point_type, std::make_pair(_transformPoint(p.at(0), SKEW, s, o, d, false), (p.at(0)).second));
773 }
775 return _snapTransformed(point_type, p, pointer, true, constraint, SKEW, s, o, d, false);
776 }
778 Inkscape::SnappedPoint SnapManager::findBestSnap(Geom::Point const &p, Inkscape::SnapSourceType const source_type, SnappedConstraints &sc, bool constrained) const
779 {
781 /*
782 std::cout << "Type and number of snapped constraints: " << std::endl;
783 std::cout << " Points : " << sc.points.size() << std::endl;
784 std::cout << " Lines : " << sc.lines.size() << std::endl;
785 std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl;
786 std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl;
787 std::cout << " Curves : " << sc.curves.size()<< std::endl;
788 */
790 // Store all snappoints
791 std::list<Inkscape::SnappedPoint> sp_list;
793 // search for the closest snapped point
794 Inkscape::SnappedPoint closestPoint;
795 if (getClosestSP(sc.points, closestPoint)) {
796 sp_list.push_back(closestPoint);
797 }
799 // search for the closest snapped curve
800 Inkscape::SnappedCurve closestCurve;
801 if (getClosestCurve(sc.curves, closestCurve)) {
802 sp_list.push_back(Inkscape::SnappedPoint(closestCurve));
803 }
805 if (snapprefs.getSnapIntersectionCS()) {
806 // search for the closest snapped intersection of curves
807 Inkscape::SnappedPoint closestCurvesIntersection;
808 if (getClosestIntersectionCS(sc.curves, p, closestCurvesIntersection, _desktop->dt2doc())) {
809 closestCurvesIntersection.setSource(source_type);
810 sp_list.push_back(closestCurvesIntersection);
811 }
812 }
814 // search for the closest snapped grid line
815 Inkscape::SnappedLine closestGridLine;
816 if (getClosestSL(sc.grid_lines, closestGridLine)) {
817 sp_list.push_back(Inkscape::SnappedPoint(closestGridLine));
818 }
820 // search for the closest snapped guide line
821 Inkscape::SnappedLine closestGuideLine;
822 if (getClosestSL(sc.guide_lines, closestGuideLine)) {
823 sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine));
824 }
826 // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated
827 // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path
829 // When doing a constrained snap however, we're already at an intersection of the constrained line and
830 // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's
831 // no need to look for additional intersections
832 if (!constrained) {
833 // search for the closest snapped intersection of grid lines
834 Inkscape::SnappedPoint closestGridPoint;
835 if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) {
836 closestGridPoint.setSource(source_type);
837 closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION);
838 sp_list.push_back(closestGridPoint);
839 }
841 // search for the closest snapped intersection of guide lines
842 Inkscape::SnappedPoint closestGuidePoint;
843 if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) {
844 closestGuidePoint.setSource(source_type);
845 closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION);
846 sp_list.push_back(closestGuidePoint);
847 }
849 // search for the closest snapped intersection of grid with guide lines
850 if (snapprefs.getSnapIntersectionGG()) {
851 Inkscape::SnappedPoint closestGridGuidePoint;
852 if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) {
853 closestGridGuidePoint.setSource(source_type);
854 closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION);
855 sp_list.push_back(closestGridGuidePoint);
856 }
857 }
858 }
860 // now let's see which snapped point gets a thumbs up
861 Inkscape::SnappedPoint bestSnappedPoint = Inkscape::SnappedPoint(p, Inkscape::SNAPSOURCE_UNDEFINED, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false);
862 // std::cout << "Finding the best snap..." << std::endl;
863 for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) {
864 // first find out if this snapped point is within snapping range
865 // std::cout << "sp = " << from_2geom((*i).getPoint());
866 if ((*i).getSnapDistance() <= (*i).getTolerance()) {
867 // if it's the first point, or if it is closer than the best snapped point so far
868 if (i == sp_list.begin() || bestSnappedPoint.isOtherSnapBetter(*i, false)) {
869 // then prefer this point over the previous one
870 bestSnappedPoint = *i;
871 }
872 }
873 // std::cout << std::endl;
874 }
876 // Update the snap indicator, if requested
877 if (_snapindicator) {
878 if (bestSnappedPoint.getSnapped()) {
879 _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint);
880 } else {
881 _desktop->snapindicator->remove_snaptarget();
882 }
883 }
885 // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl;
886 return bestSnappedPoint;
887 }
889 void SnapManager::setup(SPDesktop const *desktop,
890 bool snapindicator,
891 SPItem const *item_to_ignore,
892 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
893 SPGuide *guide_to_ignore)
894 {
895 g_assert(desktop != NULL);
896 _item_to_ignore = item_to_ignore;
897 _items_to_ignore = NULL;
898 _desktop = desktop;
899 _snapindicator = snapindicator;
900 _unselected_nodes = unselected_nodes;
901 _guide_to_ignore = guide_to_ignore;
902 }
904 void SnapManager::setup(SPDesktop const *desktop,
905 bool snapindicator,
906 std::vector<SPItem const *> &items_to_ignore,
907 std::vector<std::pair<Geom::Point, int> > *unselected_nodes,
908 SPGuide *guide_to_ignore)
909 {
910 g_assert(desktop != NULL);
911 _item_to_ignore = NULL;
912 _items_to_ignore = &items_to_ignore;
913 _desktop = desktop;
914 _snapindicator = snapindicator;
915 _unselected_nodes = unselected_nodes;
916 _guide_to_ignore = guide_to_ignore;
917 }
919 SPDocument *SnapManager::getDocument() const
920 {
921 return _named_view->document;
922 }
924 Geom::Point SnapManager::_transformPoint(std::pair<Geom::Point, int> const &p,
925 Transformation const transformation_type,
926 Geom::Point const &transformation,
927 Geom::Point const &origin,
928 Geom::Dim2 const dim,
929 bool const uniform) const
930 {
931 /* Work out the transformed version of this point */
932 Geom::Point transformed;
933 switch (transformation_type) {
934 case TRANSLATION:
935 transformed = p.first + transformation;
936 break;
937 case SCALE:
938 transformed = (p.first - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin;
939 break;
940 case STRETCH:
941 {
942 Geom::Scale s(1, 1);
943 if (uniform)
944 s[Geom::X] = s[Geom::Y] = transformation[dim];
945 else {
946 s[dim] = transformation[dim];
947 s[1 - dim] = 1;
948 }
949 transformed = ((p.first - origin) * s) + origin;
950 break;
951 }
952 case SKEW:
953 // Apply the skew factor
954 transformed[dim] = (p.first)[dim] + transformation[0] * ((p.first)[1 - dim] - origin[1 - dim]);
955 // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed.
956 // Apply that scale factor here
957 transformed[1-dim] = (p.first - origin)[1 - dim] * transformation[1] + origin[1 - dim];
958 break;
959 default:
960 g_assert_not_reached();
961 }
963 return transformed;
964 }
966 void SnapManager::_displaySnapsource(Inkscape::SnapPreferences::PointType point_type, std::pair<Geom::Point, int> const &p) const {
968 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
969 if (prefs->getBool("/options/snapclosestonly/value")) {
970 bool p_is_a_node = point_type & Inkscape::SnapPreferences::SNAPPOINT_NODE;
971 bool p_is_a_bbox = point_type & Inkscape::SnapPreferences::SNAPPOINT_BBOX;
972 if (snapprefs.getSnapEnabledGlobally() && ((p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) {
973 _desktop->snapindicator->set_new_snapsource(p);
974 } else {
975 _desktop->snapindicator->remove_snapsource();
976 }
977 }
978 }
980 /*
981 Local Variables:
982 mode:c++
983 c-file-style:"stroustrup"
984 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
985 indent-tabs-mode:nil
986 fill-column:99
987 End:
988 */
989 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :