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* Released under GNU GPL, read the file 'COPYING' for more information.
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#include "snapped-point.h"
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#include "preferences.h"
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// overloaded constructor
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Inkscape::SnappedPoint::SnappedPoint(NR::Point p, NR::Coord d, NR::Coord t, bool a)
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: _point(p), _distance(d), _tolerance(t), _always_snap(a)
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Inkscape::SnappedPoint::SnappedPoint(Geom::Point const &p, SnapSourceType const &source, SnapTargetType const &target, Geom::Coord const &d, Geom::Coord const &t, bool const &a, bool const &fully_constrained)
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: _point(p), _source(source), _target(target), _distance(d), _tolerance(std::max(t,1.0)), _always_snap(a)
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// tolerance should never be smaller than 1 px, as it is used for normalization in isOtherSnapBetter. We don't want a division by zero.
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_at_intersection = false;
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_fully_constrained = fully_constrained;
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_second_distance = NR_HUGE;
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_second_tolerance = 0;
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_second_tolerance = 1;
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_second_always_snap = false;
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_transformation = Geom::Point(1,1);
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_pointer_distance = NR_HUGE;
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Inkscape::SnappedPoint::SnappedPoint(NR::Point p, NR::Coord d, NR::Coord t, bool a, bool at_intersection, NR::Coord d2, NR::Coord t2, bool a2)
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: _point(p), _distance(d), _tolerance(t), _always_snap(a), _at_intersection(at_intersection),
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_second_distance(d2), _second_tolerance(t2), _second_always_snap(a2)
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Inkscape::SnappedPoint::SnappedPoint(Geom::Point const &p, SnapSourceType const &source, SnapTargetType const &target, Geom::Coord const &d, Geom::Coord const &t, bool const &a, bool const &at_intersection, bool const &fully_constrained, Geom::Coord const &d2, Geom::Coord const &t2, bool const &a2)
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: _point(p), _source(source), _target(target), _at_intersection(at_intersection), _fully_constrained(fully_constrained), _distance(d), _tolerance(std::max(t,1.0)), _always_snap(a),
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_second_distance(d2), _second_tolerance(std::max(t2,1.0)), _second_always_snap(a2)
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// tolerance should never be smaller than 1 px, as it is used for normalization in
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// isOtherSnapBetter. We don't want a division by zero.
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_transformation = Geom::Point(1,1);
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_pointer_distance = NR_HUGE;
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Inkscape::SnappedPoint::SnappedPoint()
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_point = NR::Point(0,0);
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_point = Geom::Point(0,0);
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_source = SNAPSOURCE_UNDEFINED,
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_target = SNAPTARGET_UNDEFINED,
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_at_intersection = false;
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_fully_constrained = false;
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_distance = NR_HUGE;
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_always_snap = false;
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_at_intersection = false;
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_second_distance = NR_HUGE;
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_second_tolerance = 0;
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_second_tolerance = 1;
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_second_always_snap = false;
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_transformation = Geom::Point(1,1);
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_pointer_distance = NR_HUGE;
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Inkscape::SnappedPoint::~SnappedPoint()
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NR::Coord Inkscape::SnappedPoint::getDistance() const
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NR::Coord Inkscape::SnappedPoint::getTolerance() const
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bool Inkscape::SnappedPoint::getAlwaysSnap() const
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NR::Coord Inkscape::SnappedPoint::getSecondDistance() const
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return _second_distance;
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NR::Coord Inkscape::SnappedPoint::getSecondTolerance() const
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return _second_tolerance;
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bool Inkscape::SnappedPoint::getSecondAlwaysSnap() const
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return _second_always_snap;
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NR::Point Inkscape::SnappedPoint::getPoint() const
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void Inkscape::SnappedPoint::getPoint(Geom::Point &p) const
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// When we have snapped
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// then return the snapped point by overwriting p
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} //otherwise p will be left untouched; this way the caller doesn't have to check wether we've snapped
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// search for the closest snapped point
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bool getClosestSP(std::list<Inkscape::SnappedPoint> &list, Inkscape::SnappedPoint &result)
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bool getClosestSP(std::list<Inkscape::SnappedPoint> &list, Inkscape::SnappedPoint &result)
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bool success = false;
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for (std::list<Inkscape::SnappedPoint>::const_iterator i = list.begin(); i != list.end(); i++) {
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if ((i == list.begin()) || (*i).getDistance() < result.getDistance()) {
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if ((i == list.begin()) || (*i).getSnapDistance() < result.getSnapDistance()) {
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bool Inkscape::SnappedPoint::isOtherSnapBetter(Inkscape::SnappedPoint const &other_one, bool weighted) const
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double dist_other = other_one.getSnapDistance();
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double dist_this = getSnapDistance();
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// The distance to the pointer should only be taken into account when finding the best snapped source node (when
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// there's more than one). It is not useful when trying to find the best snapped target point.
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// (both the snap distance and the pointer distance are measured in document pixels, not in screen pixels)
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Geom::Coord const dist_pointer_other = other_one.getPointerDistance();
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Geom::Coord const dist_pointer_this = getPointerDistance();
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// Weight factor: controls which node should be preferred for snapping, which is either
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// the node with the closest snap (w = 0), or the node closest to the mousepointer (w = 1)
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Inkscape::Preferences *prefs = Inkscape::Preferences::get();
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double w = prefs->getDoubleLimited("/options/snapweight/value", 0.5, 0, 1);
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if (prefs->getBool("/options/snapclosestonly/value", false)) {
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if (!(w == 1 && dist_pointer_this == dist_pointer_other)) {
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// When accounting for the distance to the mouse pointer, then at least one of the snapped points should
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// have that distance set. If not, then this is a bug. Either "weighted" must be set to false, or the
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// mouse pointer distance must be set.
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g_assert(dist_pointer_this != NR_HUGE || dist_pointer_other != NR_HUGE);
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// The snap distance will always be smaller than the tolerance set for the snapper. The pointer distance can
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// however be very large. To compare these in a fair way, we will have to normalize these metrics first
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// The closest pointer distance will be normalized to 1.0; the other one will be > 1.0
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// The snap distance will be normalized to 1.0 if it's equal to the snapper tolerance
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double const norm_p = std::min(dist_pointer_this, dist_pointer_other);
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double const norm_t_other = std::min(50.0, other_one.getTolerance());
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double const norm_t_this = std::min(50.0, getTolerance());
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dist_other = w * dist_pointer_other / norm_p + (1-w) * dist_other / norm_t_other;
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dist_this = w * dist_pointer_this / norm_p + (1-w) * dist_this / norm_t_this;
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bool c1 = dist_other < dist_this;
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// or, if it's for a snapper with "always snap" turned on, and the previous wasn't
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bool c2 = other_one.getAlwaysSnap() && !getAlwaysSnap();
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// But in no case fall back from a snapper with "always snap" on to one with "always snap" off
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bool c2n = !other_one.getAlwaysSnap() && getAlwaysSnap();
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// or, if we have a fully constrained snappoint (e.g. to a node or an intersection), while the previous one was only partly constrained (e.g. to a line)
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bool c3 = other_one.getFullyConstrained() && !getFullyConstrained();
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// But in no case fall back; (has less priority than c3n, so it is allowed to fall back when c3 is true, see below)
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bool c3n = !other_one.getFullyConstrained() && getFullyConstrained();
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// When both are fully constrained AND coincident, then prefer nodes over intersections
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bool d = other_one.getFullyConstrained() && getFullyConstrained() && (Geom::L2(other_one.getPoint() - getPoint()) < 1e-9);
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bool c4 = d && !other_one.getAtIntersection() && getAtIntersection();
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// But don't fall back...
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bool c4n = d && other_one.getAtIntersection() && !getAtIntersection();
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// or, if it's just as close then consider the second distance
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bool c5a = (dist_other == dist_this);
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bool c5b = other_one.getSecondSnapDistance() < getSecondSnapDistance();
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// std::cout << other_one.getPoint() << " (Other one, dist = " << dist_other << ") vs. " << getPoint() << " (this one, dist = " << dist_this << ") ---> ";
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// std::cout << "c1 = " << c1 << " | c2 = " << c2 << " | c2n = " << c2n << " | c3 = " << c3 << " | c3n = " << c3n << " | c4 = " << c4 << " | c4n = " << c4n << " | c5a = " << c5a << " | c5b = " << c5b << std::endl;
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return (c1 || c2 || c3 || c4 || (c5a && c5b)) && !c2n && (!c3n || c2) && !c4n;