1 /**
2 * \file src/snapped-curve.cpp
3 * \brief SnappedCurve class.
4 *
5 * Authors:
6 * Diederik van Lierop <mail@diedenrezi.nl>
7 *
8 * Released under GNU GPL, read the file 'COPYING' for more information.
9 */
11 #include "snapped-curve.h"
12 #include <2geom/crossing.h>
13 #include <2geom/path-intersection.h>
15 Inkscape::SnappedCurve::SnappedCurve(Geom::Point const &snapped_point, Geom::Coord const &snapped_distance, Geom::Coord const &snapped_tolerance, bool const &always_snap, bool const &fully_constrained, Geom::Curve const *curve, SnapSourceType source, long source_num, SnapTargetType target, Geom::OptRect target_bbox)
16 {
17 _distance = snapped_distance;
18 _tolerance = std::max(snapped_tolerance, 1.0);
19 _always_snap = always_snap;
20 _curve = curve;
21 _second_distance = NR_HUGE;
22 _second_tolerance = 1;
23 _second_always_snap = false;
24 _point = snapped_point;
25 _at_intersection = false;
26 _fully_constrained = fully_constrained;
27 _source = source;
28 _source_num = source_num;
29 _target = target;
30 _target_bbox = target_bbox;
31 }
33 Inkscape::SnappedCurve::SnappedCurve()
34 {
35 _distance = NR_HUGE;
36 _tolerance = 1;
37 _always_snap = false;
38 _curve = NULL;
39 _second_distance = NR_HUGE;
40 _second_tolerance = 1;
41 _second_always_snap = false;
42 _point = Geom::Point(0,0);
43 _at_intersection = false;
44 _fully_constrained = false;
45 _source = SNAPSOURCE_UNDEFINED;
46 _source_num = 0;
47 _target = SNAPTARGET_UNDEFINED;
48 _target_bbox = Geom::OptRect();
49 }
51 Inkscape::SnappedCurve::~SnappedCurve()
52 {
53 }
55 Inkscape::SnappedPoint Inkscape::SnappedCurve::intersect(SnappedCurve const &curve, Geom::Point const &p, Geom::Matrix dt2doc) const
56 {
57 // Calculate the intersections of two curves, which are both within snapping range, and
58 // return only the closest intersection
59 // The point of intersection should be considered for snapping, but might be outside the snapping range
60 // PS: We need p (the location of the mouse pointer) for find out which intersection is the
61 // closest, as there might be multiple intersections of two curves
62 Geom::Crossings cs = crossings(*(this->_curve), *(curve._curve));
64 if (cs.size() > 0) {
65 // There might be multiple intersections: find the closest
66 Geom::Coord best_dist = NR_HUGE;
67 Geom::Point best_p = Geom::Point(NR_HUGE, NR_HUGE);
68 for (Geom::Crossings::const_iterator i = cs.begin(); i != cs.end(); i++) {
69 Geom::Point p_ix = this->_curve->pointAt((*i).ta);
70 Geom::Coord dist = Geom::distance(p_ix, p);
71 if (dist < best_dist) {
72 best_dist = dist;
73 best_p = p_ix;
74 }
75 }
77 // Now we've found the closest intersection, return it as a SnappedPoint
78 bool const use_this_as_primary = _distance < curve.getSnapDistance();
79 Inkscape::SnappedCurve const *primaryC = use_this_as_primary ? this : &curve;
80 Inkscape::SnappedCurve const *secondaryC = use_this_as_primary ? &curve : this;
82 // The intersection should in fact be returned in desktop coordinates
83 best_p = best_p * dt2doc;
85 Geom::Coord primaryDist = use_this_as_primary ? Geom::L2(best_p - this->getPoint()) : Geom::L2(best_p - curve.getPoint());
86 Geom::Coord secondaryDist = use_this_as_primary ? Geom::L2(best_p - curve.getPoint()) : Geom::L2(best_p - this->getPoint());
87 // TODO: Investigate whether it is possible to use document coordinates everywhere
88 // in the snapper code. Only the mouse position should be in desktop coordinates, I guess.
89 // All paths are already in document coords and we are certainly not going to change THAT.
90 return SnappedPoint(best_p, Inkscape::SNAPSOURCE_UNDEFINED, primaryC->getSourceNum(), Inkscape::SNAPTARGET_PATH_INTERSECTION, primaryDist, primaryC->getTolerance(), primaryC->getAlwaysSnap(), true, true,
91 secondaryDist, secondaryC->getTolerance(), secondaryC->getAlwaysSnap());
92 }
94 // No intersection
95 return SnappedPoint(Geom::Point(NR_HUGE, NR_HUGE), SNAPSOURCE_UNDEFINED, 0, SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false, false, NR_HUGE, 0, false);
96 }
98 // search for the closest snapped line
99 bool getClosestCurve(std::list<Inkscape::SnappedCurve> const &list, Inkscape::SnappedCurve &result)
100 {
101 bool success = false;
103 for (std::list<Inkscape::SnappedCurve>::const_iterator i = list.begin(); i != list.end(); i++) {
104 if ((i == list.begin()) || (*i).getSnapDistance() < result.getSnapDistance()) {
105 result = *i;
106 success = true;
107 }
108 }
110 return success;
111 }
113 // search for the closest intersection of two snapped curves, which are both member of the same collection
114 bool getClosestIntersectionCS(std::list<Inkscape::SnappedCurve> const &list, Geom::Point const &p, Inkscape::SnappedPoint &result, Geom::Matrix dt2doc)
115 {
116 bool success = false;
118 for (std::list<Inkscape::SnappedCurve>::const_iterator i = list.begin(); i != list.end(); i++) {
119 if ((*i).getTarget() != Inkscape::SNAPTARGET_BBOX_EDGE) { // We don't support snapping to intersections of bboxes,
120 // as this would require two bboxes two be flashed in the snap indicator
121 std::list<Inkscape::SnappedCurve>::const_iterator j = i;
122 j++;
123 for (; j != list.end(); j++) {
124 if ((*j).getTarget() != Inkscape::SNAPTARGET_BBOX_EDGE) { // We don't support snapping to intersections of bboxes
125 Inkscape::SnappedPoint sp = (*i).intersect(*j, p, dt2doc);
126 if (sp.getAtIntersection()) {
127 // if it's the first point
128 bool const c1 = !success;
129 // or, if it's closer
130 bool const c2 = sp.getSnapDistance() < result.getSnapDistance();
131 // or, if it's just as close then look at the other distance
132 // (only relevant for snapped points which are at an intersection)
133 bool const c3 = (sp.getSnapDistance() == result.getSnapDistance()) && (sp.getSecondSnapDistance() < result.getSecondSnapDistance());
134 // then prefer this point over the previous one
135 if (c1 || c2 || c3) {
136 result = sp;
137 success = true;
138 }
139 }
140 }
141 }
142 }
143 }
145 return success;
146 }
147 /*
148 Local Variables:
149 mode:c++
150 c-file-style:"stroustrup"
151 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
152 indent-tabs-mode:nil
153 fill-column:99
154 End:
155 */
156 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :