snap.cpp

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#define __SP_DESKTOP_SNAP_C__ /** * \file snap.cpp * \brief SnapManager class. * * Authors: * Lauris Kaplinski <lauris@kaplinski.com> * Frank Felfe <innerspace@iname.com> * Nathan Hurst <njh@njhurst.com> * Carl Hetherington <inkscape@carlh.net> * Diederik van Lierop <mail@diedenrezi.nl> * * Copyright (C) 2006-2007 Johan Engelen <johan@shouraizou.nl> * Copyrigth (C) 2004 Nathan Hurst * Copyright (C) 1999-2010 Authors * * Released under GNU GPL, read the file 'COPYING' for more information */ #include <utility> #include "sp-namedview.h" #include "snap.h" #include "snapped-line.h" #include "snapped-curve.h" #include "display/canvas-grid.h" #include "display/snap-indicator.h" #include "inkscape.h" #include "desktop.h" #include "selection.h" #include "sp-guide.h" #include "preferences.h" #include "event-context.h" using std::vector; /** * Construct a SnapManager for a SPNamedView. * * \param v `Owning' SPNamedView. */ 00045 SnapManager::SnapManager(SPNamedView const *v) : guide(this, 0), object(this, 0), snapprefs(), _named_view(v) { } /** * \brief Return a list of snappers * * Inkscape snaps to objects, grids, and guides. For each of these snap targets a * separate class is used, which has been derived from the base Snapper class. The * getSnappers() method returns a list of pointers to instances of this class. This * list contains exactly one instance of the guide snapper and of the object snapper * class, but any number of grid snappers (because each grid has its own snapper * instance) * * \return List of snappers that we use. */ SnapManager::SnapperList 00066 SnapManager::getSnappers() const { SnapManager::SnapperList s; s.push_back(&guide); s.push_back(&object); SnapManager::SnapperList gs = getGridSnappers(); s.splice(s.begin(), gs); return s; } /** * \brief Return a list of gridsnappers * * Each grid has its own instance of the snapper class. This way snapping can * be enabled per grid individually. A list will be returned containing the * pointers to these instances, but only for grids that are being displayed * and for which snapping is enabled. * * \return List of gridsnappers that we use. */ SnapManager::SnapperList 00089 SnapManager::getGridSnappers() const { SnapperList s; if (_desktop && _desktop->gridsEnabled() && snapprefs.getSnapToGrids()) { for ( GSList const *l = _named_view->grids; l != NULL; l = l->next) { Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data; s.push_back(grid->snapper); } } return s; } /** * \brief Return true if any snapping might occur, whether its to grids, guides or objects * * Each snapper instance handles its own snapping target, e.g. grids, guides or * objects. This method iterates through all these snapper instances and returns * true if any of the snappers might possible snap, considering only the relevant * snapping preferences. * * \return true if one of the snappers will try to snap to something. */ 00114 bool SnapManager::someSnapperMightSnap() const { if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) { return false; } SnapperList const s = getSnappers(); SnapperList::const_iterator i = s.begin(); while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) { i++; } return (i != s.end()); } /** * \return true if one of the grids might be snapped to. */ 00133 bool SnapManager::gridSnapperMightSnap() const { if ( !snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally() ) { return false; } SnapperList const s = getGridSnappers(); SnapperList::const_iterator i = s.begin(); while (i != s.end() && (*i)->ThisSnapperMightSnap() == false) { i++; } return (i != s.end()); } /** * \brief Try to snap a point to grids, guides or objects. * * Try to snap a point to grids, guides or objects, in two degrees-of-freedom, * i.e. snap in any direction on the two dimensional canvas to the nearest * snap target. freeSnapReturnByRef() is equal in snapping behavior to * freeSnap(), but the former returns the snapped point trough the referenced * parameter p. This parameter p initially contains the position of the snap * source and will we overwritten by the target position if snapping has occurred. * This makes snapping transparent to the calling code. If this is not desired * because either the calling code must know whether snapping has occurred, or * because the original position should not be touched, then freeSnap() should be * called instead. * * PS: * 1) SnapManager::setup() must have been called before calling this method, * but only once for a set of points * 2) Only to be used when a single source point is to be snapped; it assumes * that source_num = 0, which is inefficient when snapping sets our source points * * \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred * \param source_type Detailed description of the source type, will be used by the snap indicator * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation */ 00173 void SnapManager::freeSnapReturnByRef(Geom::Point &p, Inkscape::SnapSourceType const source_type, Geom::OptRect const &bbox_to_snap) const { //TODO: SnapCandidatePoint and point_type are somewhat redundant; can't we get rid of the point_type parameter? Inkscape::SnappedPoint const s = freeSnap(Inkscape::SnapCandidatePoint(p, source_type), bbox_to_snap); s.getPoint(p); } /** * \brief Try to snap a point to grids, guides or objects. * * Try to snap a point to grids, guides or objects, in two degrees-of-freedom, * i.e. snap in any direction on the two dimensional canvas to the nearest * snap target. freeSnap() is equal in snapping behavior to * freeSnapReturnByRef(). Please read the comments of the latter for more details * * PS: SnapManager::setup() must have been called before calling this method, * but only once for a set of points * * \param p Source point to be snapped * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics */ 00200 Inkscape::SnappedPoint SnapManager::freeSnap(Inkscape::SnapCandidatePoint const &p, Geom::OptRect const &bbox_to_snap) const { if (!someSnapperMightSnap()) { return Inkscape::SnappedPoint(p, Inkscape::SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false, false); } SnappedConstraints sc; SnapperList const snappers = getSnappers(); for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) { (*i)->freeSnap(sc, p, bbox_to_snap, &_items_to_ignore, _unselected_nodes); } return findBestSnap(p, sc, false); } void SnapManager::preSnap(Inkscape::SnapCandidatePoint const &p) { // setup() must have been called before calling this method! if (_snapindicator) { _snapindicator = false; // prevent other methods from drawing a snap indicator; we want to control this here Inkscape::SnappedPoint s = freeSnap(p); if (s.getSnapped()) { _desktop->snapindicator->set_new_snaptarget(s, true); } else { _desktop->snapindicator->remove_snaptarget(true); } _snapindicator = true; // restore the original value } } /** * \brief Snap to the closest multiple of a grid pitch * * When pasting, we would like to snap to the grid. Problem is that we don't know which * nodes were aligned to the grid at the time of copying, so we don't know which nodes * to snap. If we'd snap an unaligned node to the grid, previously aligned nodes would * become unaligned. That's undesirable. Instead we will make sure that the offset * between the source and its pasted copy is a multiple of the grid pitch. If the source * was aligned, then the copy will therefore also be aligned. * * PS: Whether we really find a multiple also depends on the snapping range! Most users * will have "always snap" enabled though, in which case a multiple will always be found. * PS2: When multiple grids are present then the result will become ambiguous. There is no * way to control to which grid this method will snap. * * \param t Vector that represents the offset of the pasted copy with respect to the original * \return Offset vector after snapping to the closest multiple of a grid pitch */ 00252 Geom::Point SnapManager::multipleOfGridPitch(Geom::Point const &t, Geom::Point const &origin) { if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) return t; if (_desktop && _desktop->gridsEnabled()) { bool success = false; Geom::Point nearest_multiple; Geom::Coord nearest_distance = NR_HUGE; Inkscape::SnappedPoint bestSnappedPoint(t); // It will snap to the grid for which we find the closest snap. This might be a different // grid than to which the objects were initially aligned. I don't see an easy way to fix // this, so when using multiple grids one can get unexpected results // Cannot use getGridSnappers() because we need both the grids AND their snappers // Therefore we iterate through all grids manually for (GSList const *l = _named_view->grids; l != NULL; l = l->next) { Inkscape::CanvasGrid *grid = (Inkscape::CanvasGrid*) l->data; const Inkscape::Snapper* snapper = grid->snapper; if (snapper && snapper->ThisSnapperMightSnap()) { // To find the nearest multiple of the grid pitch for a given translation t, we // will use the grid snapper. Simply snapping the value t to the grid will do, but // only if the origin of the grid is at (0,0). If it's not then compensate for this // in the translation t Geom::Point const t_offset = t + grid->origin; SnappedConstraints sc; // Only the first three parameters are being used for grid snappers snapper->freeSnap(sc, Inkscape::SnapCandidatePoint(t_offset, Inkscape::SNAPSOURCE_GRID_PITCH),Geom::OptRect(), NULL, NULL); // Find the best snap for this grid, including intersections of the grid-lines bool old_val = _snapindicator; _snapindicator = false; Inkscape::SnappedPoint s = findBestSnap(Inkscape::SnapCandidatePoint(t_offset, Inkscape::SNAPSOURCE_GRID_PITCH), sc, false, false, true); _snapindicator = old_val; if (s.getSnapped() && (s.getSnapDistance() < nearest_distance)) { // use getSnapDistance() instead of getWeightedDistance() here because the pointer's position // doesn't tell us anything about which node to snap success = true; nearest_multiple = s.getPoint() - to_2geom(grid->origin); nearest_distance = s.getSnapDistance(); bestSnappedPoint = s; } } } if (success) { bestSnappedPoint.setPoint(origin + nearest_multiple); _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint); return nearest_multiple; } } return t; } /** * \brief Try to snap a point along a constraint line to grids, guides or objects. * * Try to snap a point to grids, guides or objects, in only one degree-of-freedom, * i.e. snap in a specific direction on the two dimensional canvas to the nearest * snap target. * * constrainedSnapReturnByRef() is equal in snapping behavior to * constrainedSnap(), but the former returns the snapped point trough the referenced * parameter p. This parameter p initially contains the position of the snap * source and will we overwritten by the target position if snapping has occurred. * This makes snapping transparent to the calling code. If this is not desired * because either the calling code must know whether snapping has occurred, or * because the original position should not be touched, then constrainedSnap() should * be called instead. * * PS: * 1) SnapManager::setup() must have been called before calling this method, * but only once for a set of points * 2) Only to be used when a single source point is to be snapped; it assumes * that source_num = 0, which is inefficient when snapping sets our source points * * \param p Current position of the snap source; will be overwritten by the position of the snap target if snapping has occurred * \param source_type Detailed description of the source type, will be used by the snap indicator * \param constraint The direction or line along which snapping must occur * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation */ 00336 void SnapManager::constrainedSnapReturnByRef(Geom::Point &p, Inkscape::SnapSourceType const source_type, Inkscape::Snapper::ConstraintLine const &constraint, Geom::OptRect const &bbox_to_snap) const { Inkscape::SnappedPoint const s = constrainedSnap(Inkscape::SnapCandidatePoint(p, source_type, 0), constraint, bbox_to_snap); s.getPoint(p); } /** * \brief Try to snap a point along a constraint line to grids, guides or objects. * * Try to snap a point to grids, guides or objects, in only one degree-of-freedom, * i.e. snap in a specific direction on the two dimensional canvas to the nearest * snap target. constrainedSnap is equal in snapping behavior to * constrainedSnapReturnByRef(). Please read the comments of the latter for more details. * * PS: SnapManager::setup() must have been called before calling this method, * but only once for a set of points * * \param p Source point to be snapped * \param constraint The direction or line along which snapping must occur * \param bbox_to_snap Bounding box hulling the set of points, all from the same selection and having the same transformation */ 00361 Inkscape::SnappedPoint SnapManager::constrainedSnap(Inkscape::SnapCandidatePoint const &p, Inkscape::Snapper::ConstraintLine const &constraint, Geom::OptRect const &bbox_to_snap) const { // First project the mouse pointer onto the constraint Geom::Point pp = constraint.projection(p.getPoint()); Inkscape::SnappedPoint no_snap = Inkscape::SnappedPoint(pp, p.getSourceType(), p.getSourceNum(), Inkscape::SNAPTARGET_CONSTRAINT, Geom::L2(pp - p.getPoint()), 0, false, true, false); if (!someSnapperMightSnap()) { // Always return point on constraint return no_snap; } SnappedConstraints sc; SnapperList const snappers = getSnappers(); for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) { (*i)->constrainedSnap(sc, p, bbox_to_snap, constraint, &_items_to_ignore); } Inkscape::SnappedPoint result = findBestSnap(p, sc, true); if (result.getSnapped()) { // only change the snap indicator if we really snapped to something if (_snapindicator) { _desktop->snapindicator->set_new_snaptarget(result); } return result; } return no_snap; } /** * \brief Try to snap a point of a guide to another guide or to a node * * Try to snap a point of a guide to another guide or to a node in two degrees- * of-freedom, i.e. snap in any direction on the two dimensional canvas to the * nearest snap target. This method is used when dragging or rotating a guide * * PS: SnapManager::setup() must have been called before calling this method, * * \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 * \param guide_normal Vector normal to the guide line */ 00405 void SnapManager::guideFreeSnap(Geom::Point &p, Geom::Point const &guide_normal, SPGuideDragType drag_type) const { if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) { return; } if (!(object.GuidesMightSnap() || snapprefs.getSnapToGuides())) { return; } Inkscape::SnapCandidatePoint candidate(p, Inkscape::SNAPSOURCE_GUIDE_ORIGIN); if (drag_type == SP_DRAG_ROTATE) { candidate = Inkscape::SnapCandidatePoint(p, Inkscape::SNAPSOURCE_GUIDE); } // Snap to nodes SnappedConstraints sc; if (object.GuidesMightSnap()) { object.guideFreeSnap(sc, p, guide_normal); } // Snap to guides & grid lines SnapperList snappers = getGridSnappers(); snappers.push_back(&guide); for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) { (*i)->freeSnap(sc, candidate, Geom::OptRect(), NULL, NULL); } Inkscape::SnappedPoint const s = findBestSnap(candidate, sc, false, false); s.getPoint(p); } /** * \brief Try to snap a point on a guide to the intersection with another guide or a path * * Try to snap a point on a guide to the intersection of that guide with another * guide or with a path. The snapped point will lie somewhere on the guide-line, * making this is a constrained snap, i.e. in only one degree-of-freedom. * This method is used when dragging the origin of the guide along the guide itself. * * PS: SnapManager::setup() must have been called before calling this method, * * \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 * \param guide_normal Vector normal to the guide line */ 00452 void SnapManager::guideConstrainedSnap(Geom::Point &p, SPGuide const &guideline) const { if (!snapprefs.getSnapEnabledGlobally() || snapprefs.getSnapPostponedGlobally()) { return; } if (!(object.ThisSnapperMightSnap() || snapprefs.getSnapToGuides())) { return; } Inkscape::SnapCandidatePoint candidate(p, Inkscape::SNAPSOURCE_GUIDE_ORIGIN, Inkscape::SNAPTARGET_UNDEFINED); // Snap to nodes or paths SnappedConstraints sc; Inkscape::Snapper::ConstraintLine cl(guideline.point_on_line, Geom::rot90(guideline.normal_to_line)); if (object.ThisSnapperMightSnap()) { object.constrainedSnap(sc, candidate, Geom::OptRect(), cl, NULL); } // Snap to guides & grid lines SnapperList snappers = getGridSnappers(); snappers.push_back(&guide); for (SnapperList::const_iterator i = snappers.begin(); i != snappers.end(); i++) { (*i)->constrainedSnap(sc, candidate, Geom::OptRect(), cl, NULL); } Inkscape::SnappedPoint const s = findBestSnap(candidate, sc, false); s.getPoint(p); } /** * \brief Method for snapping sets of points while they are being transformed * * Method for snapping sets of points while they are being transformed, when using * for example the selector tool. This method is for internal use only, and should * not have to be called directly. Use freeSnapTransalation(), constrainedSnapScale(), * etc. instead. * * This is what is being done in this method: transform each point, find out whether * a free snap or constrained snap is more appropriate, do the snapping, calculate * some metrics to quantify the snap "distance", and see if it's better than the * previous snap. Finally, the best ("nearest") snap from all these points is returned. * * \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. * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed). * \param constrained true if the snap is constrained, e.g. for stretching or for purely horizontal translation. * \param constraint The direction or line along which snapping must occur, if 'constrained' is true; otherwise undefined. * \param transformation_type Type of transformation to apply to points before trying to snap them. * \param transformation Description of the transformation; details depend on the type. * \param origin Origin of the transformation, if applicable. * \param dim Dimension to which the transformation applies, if applicable. * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling. * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics. */ 00507 Inkscape::SnappedPoint SnapManager::_snapTransformed( std::vector<Inkscape::SnapCandidatePoint> const &points, Geom::Point const &pointer, bool constrained, Inkscape::Snapper::ConstraintLine const &constraint, Transformation transformation_type, Geom::Point const &transformation, Geom::Point const &origin, Geom::Dim2 dim, bool uniform) const { /* We have a list of points, which we are proposing to transform in some way. We need to see ** if any of these points, when transformed, snap to anything. If they do, we return the ** appropriate transformation with `true'; otherwise we return the original scale with `false'. */ /* Quick check to see if we have any snappers that are enabled ** Also used to globally disable all snapping */ if (someSnapperMightSnap() == false || points.size() == 0) { return Inkscape::SnappedPoint(pointer); } std::vector<Inkscape::SnapCandidatePoint> transformed_points; Geom::Rect bbox; long source_num = 0; for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = points.begin(); i != points.end(); i++) { /* Work out the transformed version of this point */ Geom::Point transformed = _transformPoint(*i, transformation_type, transformation, origin, dim, uniform); // add the current transformed point to the box hulling all transformed points if (i == points.begin()) { bbox = Geom::Rect(transformed, transformed); } else { bbox.expandTo(transformed); } transformed_points.push_back(Inkscape::SnapCandidatePoint(transformed, (*i).getSourceType(), source_num)); source_num++; } /* The current best transformation */ Geom::Point best_transformation = transformation; /* The current best metric for the best transformation; lower is better, NR_HUGE ** means that we haven't snapped anything. */ Geom::Point best_scale_metric(NR_HUGE, NR_HUGE); Inkscape::SnappedPoint best_snapped_point; g_assert(best_snapped_point.getAlwaysSnap() == false); // Check initialization of snapped point g_assert(best_snapped_point.getAtIntersection() == false); std::vector<Inkscape::SnapCandidatePoint>::iterator j = transformed_points.begin(); // std::cout << std::endl; bool first_free_snap = true; for (std::vector<Inkscape::SnapCandidatePoint>::const_iterator i = points.begin(); i != points.end(); i++) { /* Snap it */ Inkscape::SnappedPoint snapped_point; Inkscape::Snapper::ConstraintLine dedicated_constraint = constraint; Geom::Point const b = ((*i).getPoint() - origin); // vector to original point if (constrained) { if ((transformation_type == SCALE || transformation_type == STRETCH) && uniform) { // When uniformly scaling, each point will have its own unique constraint line, // running from the scaling origin to the original untransformed point. We will // calculate that line here dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, b); } else if (transformation_type == STRETCH) { // when non-uniform stretching { dedicated_constraint = Inkscape::Snapper::ConstraintLine((*i).getPoint(), component_vectors[dim]); } else if (transformation_type == TRANSLATION) { // When doing a constrained translation, all points will move in the same direction, i.e. // either horizontally or vertically. The lines along which they move are therefore all // parallel, but might not be colinear. Therefore we will have to set the point through // which the constraint-line runs here, for each point individually. dedicated_constraint.setPoint((*i).getPoint()); } // else: leave the original constraint, e.g. for skewing if (transformation_type == SCALE && !uniform) { g_warning("Non-uniform constrained scaling is not supported!"); } snapped_point = constrainedSnap(*j, dedicated_constraint, bbox); } else { bool const c1 = fabs(b[Geom::X]) < 1e-6; bool const c2 = fabs(b[Geom::Y]) < 1e-6; if (transformation_type == SCALE && (c1 || c2) && !(c1 && c2)) { // When scaling, a point aligned either horizontally or vertically with the origin can only // move in that specific direction; therefore it should only snap in that direction, otherwise // we will get snapped points with an invalid transformation dedicated_constraint = Inkscape::Snapper::ConstraintLine(origin, component_vectors[c1]); snapped_point = constrainedSnap(*j, dedicated_constraint, bbox); } else { // If we have a collection of SnapCandidatePoints, with mixed constrained snapping and free snapping // requirements, then freeSnap might never see the SnapCandidatePoint with source_num == 0. The freeSnap() // method in the object snapper depends on this, because only for source-num == 0 the target nodes will // be collected. Therefore we enforce that the first SnapCandidatePoint that is to be freeSnapped always // has source_num == 0; // TODO: This is a bit ugly so fix this; do we need sourcenum for anything else? if we don't then get rid // of it and explicitely communicate to the object snapper that this is a first point if (first_free_snap) { (*j).setSourceNum(0); first_free_snap = false; } snapped_point = freeSnap(*j, bbox); } } // std::cout << "dist = " << snapped_point.getSnapDistance() << std::endl; snapped_point.setPointerDistance(Geom::L2(pointer - (*i).getPoint())); Geom::Point result; if (snapped_point.getSnapped()) { /* We snapped. Find the transformation that describes where the snapped point has ** ended up, and also the metric for this transformation. */ Geom::Point const a = (snapped_point.getPoint() - origin); // vector to snapped point //Geom::Point const b = (*i - origin); // vector to original point switch (transformation_type) { case TRANSLATION: result = snapped_point.getPoint() - (*i).getPoint(); /* Consider the case in which a box is almost aligned with a grid in both * horizontal and vertical directions. The distance to the intersection of * the grid lines will always be larger then the distance to a single grid * line. If we prefer snapping to an intersection instead of to a single * grid line, then we cannot use "metric = Geom::L2(result)". Therefore the * snapped distance will be used as a metric. Please note that the snapped * distance is defined as the distance to the nearest line of the intersection, * and not to the intersection itself! */ // Only for translations, the relevant metric will be the real snapped distance, // so we don't have to do anything special here break; case SCALE: { result = Geom::Point(NR_HUGE, NR_HUGE); // If this point *i is horizontally or vertically aligned with // the origin of the scaling, then it will scale purely in X or Y // We can therefore only calculate the scaling in this direction // and the scaling factor for the other direction should remain // untouched (unless scaling is uniform of course) for (int index = 0; index < 2; index++) { if (fabs(b[index]) > 1e-6) { // if SCALING CAN occur in this direction if (fabs(fabs(a[index]/b[index]) - fabs(transformation[index])) > 1e-12) { // if SNAPPING DID occur in this direction result[index] = a[index] / b[index]; // then calculate it! } // we might leave result[1-index] = NR_HUGE // if scaling didn't occur in the other direction } } if (uniform) { if (fabs(result[0]) < fabs(result[1])) { result[1] = result[0]; } else { result[0] = result[1]; } } // Compare the resulting scaling with the desired scaling Geom::Point scale_metric = Geom::abs(result - transformation); // One or both of its components might be NR_HUGE snapped_point.setSnapDistance(std::min(scale_metric[0], scale_metric[1])); snapped_point.setSecondSnapDistance(std::max(scale_metric[0], scale_metric[1])); break; } case STRETCH: result = Geom::Point(NR_HUGE, NR_HUGE); if (fabs(b[dim]) > 1e-6) { // if STRETCHING will occur for this point result[dim] = a[dim] / b[dim]; result[1-dim] = uniform ? result[dim] : 1; } else { // STRETCHING might occur for this point, but only when the stretching is uniform if (uniform && fabs(b[1-dim]) > 1e-6) { result[1-dim] = a[1-dim] / b[1-dim]; result[dim] = result[1-dim]; } } // Store the metric for this transformation as a virtual distance snapped_point.setSnapDistance(std::abs(result[dim] - transformation[dim])); snapped_point.setSecondSnapDistance(NR_HUGE); break; case SKEW: result[0] = (snapped_point.getPoint()[dim] - ((*i).getPoint())[dim]) / (((*i).getPoint())[1 - dim] - origin[1 - dim]); // skew factor result[1] = transformation[1]; // scale factor // Store the metric for this transformation as a virtual distance snapped_point.setSnapDistance(std::abs(result[0] - transformation[0])); snapped_point.setSecondSnapDistance(NR_HUGE); break; default: g_assert_not_reached(); } if (best_snapped_point.isOtherSnapBetter(snapped_point, true)) { best_transformation = result; best_snapped_point = snapped_point; } } j++; } Geom::Coord best_metric; if (transformation_type == SCALE) { // When scaling, don't ever exit with one of scaling components set to NR_HUGE for (int index = 0; index < 2; index++) { if (best_transformation[index] == NR_HUGE) { if (uniform && best_transformation[1-index] < NR_HUGE) { best_transformation[index] = best_transformation[1-index]; } else { best_transformation[index] = transformation[index]; } } } } best_metric = best_snapped_point.getSnapDistance(); best_snapped_point.setTransformation(best_transformation); // Using " < 1e6" instead of " < NR_HUGE" for catching some rounding errors // These rounding errors might be caused by NRRects, see bug #1584301 best_snapped_point.setSnapDistance(best_metric < 1e6 ? best_metric : NR_HUGE); return best_snapped_point; } /** * \brief Apply a translation to a set of points and try to snap freely in 2 degrees-of-freedom * * \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. * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed). * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics. */ 00740 Inkscape::SnappedPoint SnapManager::freeSnapTranslation(std::vector<Inkscape::SnapCandidatePoint> const &p, Geom::Point const &pointer, Geom::Point const &tr) const { if (p.size() == 1) { Geom::Point pt = _transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false); _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType())); } return _snapTransformed(p, pointer, false, Geom::Point(0,0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false); } /** * \brief Apply a translation to a set of points and try to snap along a constraint * * \param point_type Category of points to which the source point belongs: node or bounding box. * \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. * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed). * \param constraint The direction or line along which snapping must occur. * \param tr Proposed translation; the final translation can only be calculated after snapping has occurred. * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics. */ 00763 Inkscape::SnappedPoint SnapManager::constrainedSnapTranslation(std::vector<Inkscape::SnapCandidatePoint> const &p, Geom::Point const &pointer, Inkscape::Snapper::ConstraintLine const &constraint, Geom::Point const &tr) const { if (p.size() == 1) { Geom::Point pt = _transformPoint(p.at(0), TRANSLATION, tr, Geom::Point(0,0), Geom::X, false); _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType())); } return _snapTransformed(p, pointer, true, constraint, TRANSLATION, tr, Geom::Point(0,0), Geom::X, false); } /** * \brief Apply a scaling to a set of points and try to snap freely in 2 degrees-of-freedom * * \param point_type Category of points to which the source point belongs: node or bounding box. * \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. * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed). * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred * \param o Origin of the scaling * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics. */ 00788 Inkscape::SnappedPoint SnapManager::freeSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p, Geom::Point const &pointer, Geom::Scale const &s, Geom::Point const &o) const { if (p.size() == 1) { Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false); _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType())); } return _snapTransformed(p, pointer, false, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, false); } /** * \brief Apply a scaling to a set of points and snap such that the aspect ratio of the selection is preserved * * \param point_type Category of points to which the source point belongs: node or bounding box. * \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. * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed). * \param s Proposed scaling; the final scaling can only be calculated after snapping has occurred * \param o Origin of the scaling * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics. */ 00813 Inkscape::SnappedPoint SnapManager::constrainedSnapScale(std::vector<Inkscape::SnapCandidatePoint> const &p, Geom::Point const &pointer, Geom::Scale const &s, Geom::Point const &o) const { // When constrained scaling, only uniform scaling is supported. if (p.size() == 1) { Geom::Point pt = _transformPoint(p.at(0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true); _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType())); } return _snapTransformed(p, pointer, true, Geom::Point(0,0), SCALE, Geom::Point(s[Geom::X], s[Geom::Y]), o, Geom::X, true); } /** * \brief Apply a stretch to a set of points and snap such that the direction of the stretch is preserved * * \param point_type Category of points to which the source point belongs: node or bounding box. * \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. * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed). * \param s Proposed stretch; the final stretch can only be calculated after snapping has occurred * \param o Origin of the stretching * \param d Dimension in which to apply proposed stretch. * \param u true if the stretch should be uniform (i.e. to be applied equally in both dimensions) * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics. */ 00840 Inkscape::SnappedPoint SnapManager::constrainedSnapStretch(std::vector<Inkscape::SnapCandidatePoint> const &p, Geom::Point const &pointer, Geom::Coord const &s, Geom::Point const &o, Geom::Dim2 d, bool u) const { if (p.size() == 1) { Geom::Point pt = _transformPoint(p.at(0), STRETCH, Geom::Point(s, s), o, d, u); _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType())); } return _snapTransformed(p, pointer, true, Geom::Point(0,0), STRETCH, Geom::Point(s, s), o, d, u); } /** * \brief Apply a skew to a set of points and snap such that the direction of the skew is preserved * * \param point_type Category of points to which the source point belongs: node or bounding box. * \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. * \param pointer Location of the mouse pointer at the time dragging started (i.e. when the selection was still untransformed). * \param constraint The direction or line along which snapping must occur. * \param s Proposed skew; the final skew can only be calculated after snapping has occurred * \param o Origin of the proposed skew * \param d Dimension in which to apply proposed skew. * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics. */ 00868 Inkscape::SnappedPoint SnapManager::constrainedSnapSkew(std::vector<Inkscape::SnapCandidatePoint> const &p, Geom::Point const &pointer, Inkscape::Snapper::ConstraintLine const &constraint, Geom::Point const &s, Geom::Point const &o, Geom::Dim2 d) const { // "s" contains skew factor in s[0], and scale factor in s[1] // Snapping the nodes of the bounding box of a selection that is being transformed, will only work if // the transformation of the bounding box is equal to the transformation of the individual nodes. This is // NOT the case for example when rotating or skewing. The bounding box itself cannot possibly rotate or skew, // so it's corners have a different transformation. The snappers cannot handle this, therefore snapping // of bounding boxes is not allowed here. if (p.size() > 0) { g_assert(!(p.at(0).getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY)); } if (p.size() == 1) { Geom::Point pt = _transformPoint(p.at(0), SKEW, s, o, d, false); _displaySnapsource(Inkscape::SnapCandidatePoint(pt, p.at(0).getSourceType())); } return _snapTransformed(p, pointer, true, constraint, SKEW, s, o, d, false); } /** * \brief Given a set of possible snap targets, find the best target (which is not necessarily * also the nearest target), and show the snap indicator if requested * * \param p Source point to be snapped * \param sc A structure holding all snap targets that have been found so far * \param constrained True if the snap is constrained, e.g. for stretching or for purely horizontal translation. * \param noCurves If true, then do consider snapping to intersections of curves, but not to the curves themselves * \param allowOffScreen If true, then snapping to points which are off the screen is allowed (needed for example when pasting to the grid) * \return An instance of the SnappedPoint class, which holds data on the snap source, snap target, and various metrics */ 00906 Inkscape::SnappedPoint SnapManager::findBestSnap(Inkscape::SnapCandidatePoint const &p, SnappedConstraints const &sc, bool constrained, bool noCurves, bool allowOffScreen) const { /* std::cout << "Type and number of snapped constraints: " << std::endl; std::cout << " Points : " << sc.points.size() << std::endl; std::cout << " Lines : " << sc.lines.size() << std::endl; std::cout << " Grid lines : " << sc.grid_lines.size()<< std::endl; std::cout << " Guide lines : " << sc.guide_lines.size()<< std::endl; std::cout << " Curves : " << sc.curves.size()<< std::endl; */ // Store all snappoints std::list<Inkscape::SnappedPoint> sp_list; // search for the closest snapped point Inkscape::SnappedPoint closestPoint; if (getClosestSP(sc.points, closestPoint)) { sp_list.push_back(closestPoint); } // search for the closest snapped curve if (!noCurves) { Inkscape::SnappedCurve closestCurve; if (getClosestCurve(sc.curves, closestCurve)) { sp_list.push_back(Inkscape::SnappedPoint(closestCurve)); } } if (snapprefs.getSnapIntersectionCS()) { // search for the closest snapped intersection of curves Inkscape::SnappedPoint closestCurvesIntersection; if (getClosestIntersectionCS(sc.curves, p.getPoint(), closestCurvesIntersection, _desktop->dt2doc())) { closestCurvesIntersection.setSource(p.getSourceType()); sp_list.push_back(closestCurvesIntersection); } } // search for the closest snapped grid line Inkscape::SnappedLine closestGridLine; if (getClosestSL(sc.grid_lines, closestGridLine)) { sp_list.push_back(Inkscape::SnappedPoint(closestGridLine)); } // search for the closest snapped guide line Inkscape::SnappedLine closestGuideLine; if (getClosestSL(sc.guide_lines, closestGuideLine)) { sp_list.push_back(Inkscape::SnappedPoint(closestGuideLine)); } // When freely snapping to a grid/guide/path, only one degree of freedom is eliminated // Therefore we will try get fully constrained by finding an intersection with another grid/guide/path // When doing a constrained snap however, we're already at an intersection of the constrained line and // the grid/guide/path we're snapping to. This snappoint is therefore fully constrained, so there's // no need to look for additional intersections if (!constrained) { // search for the closest snapped intersection of grid lines Inkscape::SnappedPoint closestGridPoint; if (getClosestIntersectionSL(sc.grid_lines, closestGridPoint)) { closestGridPoint.setSource(p.getSourceType()); closestGridPoint.setTarget(Inkscape::SNAPTARGET_GRID_INTERSECTION); sp_list.push_back(closestGridPoint); } // search for the closest snapped intersection of guide lines Inkscape::SnappedPoint closestGuidePoint; if (getClosestIntersectionSL(sc.guide_lines, closestGuidePoint)) { closestGuidePoint.setSource(p.getSourceType()); closestGuidePoint.setTarget(Inkscape::SNAPTARGET_GUIDE_INTERSECTION); sp_list.push_back(closestGuidePoint); } // search for the closest snapped intersection of grid with guide lines if (snapprefs.getSnapIntersectionGG()) { Inkscape::SnappedPoint closestGridGuidePoint; if (getClosestIntersectionSL(sc.grid_lines, sc.guide_lines, closestGridGuidePoint)) { closestGridGuidePoint.setSource(p.getSourceType()); closestGridGuidePoint.setTarget(Inkscape::SNAPTARGET_GRID_GUIDE_INTERSECTION); sp_list.push_back(closestGridGuidePoint); } } } // now let's see which snapped point gets a thumbs up Inkscape::SnappedPoint bestSnappedPoint(p.getPoint()); // std::cout << "Finding the best snap..." << std::endl; for (std::list<Inkscape::SnappedPoint>::const_iterator i = sp_list.begin(); i != sp_list.end(); i++) { // std::cout << "sp = " << (*i).getPoint() << " | source = " << (*i).getSource() << " | target = " << (*i).getTarget(); bool onScreen = _desktop->get_display_area().contains((*i).getPoint()); if (onScreen || allowOffScreen) { // Only snap to points which are not off the screen if ((*i).getSnapDistance() <= (*i).getTolerance()) { // Only snap to points within snapping range // if it's the first point, or if it is closer than the best snapped point so far if (i == sp_list.begin() || bestSnappedPoint.isOtherSnapBetter(*i, false)) { // then prefer this point over the previous one bestSnappedPoint = *i; } } } // std::cout << std::endl; } // Update the snap indicator, if requested if (_snapindicator) { if (bestSnappedPoint.getSnapped()) { _desktop->snapindicator->set_new_snaptarget(bestSnappedPoint); } else { _desktop->snapindicator->remove_snaptarget(); } } // std::cout << "findBestSnap = " << bestSnappedPoint.getPoint() << " | dist = " << bestSnappedPoint.getSnapDistance() << std::endl; return bestSnappedPoint; } /// Convenience shortcut when there is only one item to ignore 01027 void SnapManager::setup(SPDesktop const *desktop, bool snapindicator, SPItem const *item_to_ignore, std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes, SPGuide *guide_to_ignore) { g_assert(desktop != NULL); _items_to_ignore.clear(); _items_to_ignore.push_back(item_to_ignore); _desktop = desktop; _snapindicator = snapindicator; _unselected_nodes = unselected_nodes; _guide_to_ignore = guide_to_ignore; } /** * \brief Prepare the snap manager for the actual snapping, which includes building a list of snap targets * to ignore and toggling the snap indicator * * There are two overloaded setup() methods, of which the other one only allows for a single item to be ignored * whereas this one will take a list of items to ignore * * \param desktop Reference to the desktop to which this snap manager is attached * \param snapindicator If true then a snap indicator will be displayed automatically (when enabled in the preferences) * \param items_to_ignore These items will not be snapped to, e.g. the items that are currently being dragged. This avoids "self-snapping" * \param unselected_nodes Stationary nodes of the path that is currently being edited in the node tool and * that can be snapped too. Nodes not in this list will not be snapped to, to avoid "self-snapping". Of each * unselected node both the position (Geom::Point) and the type (Inkscape::SnapTargetType) will be stored * \param guide_to_ignore Guide that is currently being dragged and should not be snapped to */ 01058 void SnapManager::setup(SPDesktop const *desktop, bool snapindicator, std::vector<SPItem const *> &items_to_ignore, std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes, SPGuide *guide_to_ignore) { g_assert(desktop != NULL); _items_to_ignore = items_to_ignore; _desktop = desktop; _snapindicator = snapindicator; _unselected_nodes = unselected_nodes; _guide_to_ignore = guide_to_ignore; } /// Setup, taking the list of items to ignore from the desktop's selection. 01073 void SnapManager::setupIgnoreSelection(SPDesktop const *desktop, bool snapindicator, std::vector<Inkscape::SnapCandidatePoint> *unselected_nodes, SPGuide *guide_to_ignore) { _desktop = desktop; _snapindicator = snapindicator; _unselected_nodes = unselected_nodes; _guide_to_ignore = guide_to_ignore; _items_to_ignore.clear(); Inkscape::Selection *sel = _desktop->selection; GSList const *items = sel->itemList(); for (GSList *i = const_cast<GSList*>(items); i; i = i->next) { _items_to_ignore.push_back(static_cast<SPItem const *>(i->data)); } } SPDocument *SnapManager::getDocument() const { return _named_view->document; } /** * \brief Takes an untransformed point, applies the given transformation, and returns the transformed point. Eliminates lots of duplicated code * * \param p The untransformed position of the point, paired with an identifier of the type of the snap source. * \param transformation_type Type of transformation to apply. * \param transformation Mathematical description of the transformation; details depend on the type. * \param origin Origin of the transformation, if applicable. * \param dim Dimension to which the transformation applies, if applicable. * \param uniform true if the transformation should be uniform; only applicable for stretching and scaling. * \return The position of the point after transformation */ 01108 Geom::Point SnapManager::_transformPoint(Inkscape::SnapCandidatePoint const &p, Transformation const transformation_type, Geom::Point const &transformation, Geom::Point const &origin, Geom::Dim2 const dim, bool const uniform) const { /* Work out the transformed version of this point */ Geom::Point transformed; switch (transformation_type) { case TRANSLATION: transformed = p.getPoint() + transformation; break; case SCALE: transformed = (p.getPoint() - origin) * Geom::Scale(transformation[Geom::X], transformation[Geom::Y]) + origin; break; case STRETCH: { Geom::Scale s(1, 1); if (uniform) s[Geom::X] = s[Geom::Y] = transformation[dim]; else { s[dim] = transformation[dim]; s[1 - dim] = 1; } transformed = ((p.getPoint() - origin) * s) + origin; break; } case SKEW: // Apply the skew factor transformed[dim] = (p.getPoint())[dim] + transformation[0] * ((p.getPoint())[1 - dim] - origin[1 - dim]); // While skewing, mirroring and scaling (by integer multiples) in the opposite direction is also allowed. // Apply that scale factor here transformed[1-dim] = (p.getPoint() - origin)[1 - dim] * transformation[1] + origin[1 - dim]; break; default: g_assert_not_reached(); } return transformed; } /** * \brief Mark the location of the snap source (not the snap target!) on the canvas by drawing a symbol * * \param point_type Category of points to which the source point belongs: node, guide or bounding box * \param p The transformed position of the source point, paired with an identifier of the type of the snap source. */ 01157 void SnapManager::_displaySnapsource(Inkscape::SnapCandidatePoint const &p) const { Inkscape::Preferences *prefs = Inkscape::Preferences::get(); if (prefs->getBool("/options/snapclosestonly/value")) { bool p_is_a_node = p.getSourceType() & Inkscape::SNAPSOURCE_NODE_CATEGORY; bool p_is_a_bbox = p.getSourceType() & Inkscape::SNAPSOURCE_BBOX_CATEGORY; if (snapprefs.getSnapEnabledGlobally() && ((p_is_a_node && snapprefs.getSnapModeNode()) || (p_is_a_bbox && snapprefs.getSnapModeBBox()))) { _desktop->snapindicator->set_new_snapsource(p); } else { _desktop->snapindicator->remove_snapsource(); } } } /* Local Variables: mode:c++ c-file-style:"stroustrup" c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +)) indent-tabs-mode:nil fill-column:99 End: */ // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :

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