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, int num_path, int num_segm, 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 _num_path = num_path;
18 _num_segm = num_segm;
19 _distance = snapped_distance;
20 _tolerance = std::max(snapped_tolerance, 1.0);
21 _always_snap = always_snap;
22 _curve = curve;
23 _second_distance = NR_HUGE;
24 _second_tolerance = 1;
25 _second_always_snap = false;
26 _point = snapped_point;
27 _at_intersection = false;
28 _fully_constrained = fully_constrained;
29 _source = source;
30 _source_num = source_num;
31 _target = target;
32 _target_bbox = target_bbox;
33 }
35 Inkscape::SnappedCurve::SnappedCurve()
36 {
37 _num_path = 0;
38 _num_segm = 0;
39 _distance = NR_HUGE;
40 _tolerance = 1;
41 _always_snap = false;
42 _curve = NULL;
43 _second_distance = NR_HUGE;
44 _second_tolerance = 1;
45 _second_always_snap = false;
46 _point = Geom::Point(0,0);
47 _at_intersection = false;
48 _fully_constrained = false;
49 _source = SNAPSOURCE_UNDEFINED;
50 _source_num = 0;
51 _target = SNAPTARGET_UNDEFINED;
52 _target_bbox = Geom::OptRect();
53 }
55 Inkscape::SnappedCurve::~SnappedCurve()
56 {
57 }
59 Inkscape::SnappedPoint Inkscape::SnappedCurve::intersect(SnappedCurve const &curve, Geom::Point const &p, Geom::Matrix dt2doc) const
60 {
61 // Calculate the intersections of two curves, which are both within snapping range, and
62 // return only the closest intersection
63 // The point of intersection should be considered for snapping, but might be outside the snapping range
64 // PS: We need p (the location of the mouse pointer) for find out which intersection is the
65 // closest, as there might be multiple intersections of two curves
66 Geom::Crossings cs = crossings(*(this->_curve), *(curve._curve));
68 if (cs.size() > 0) {
69 // There might be multiple intersections: find the closest
70 Geom::Coord best_dist = NR_HUGE;
71 Geom::Point best_p = Geom::Point(NR_HUGE, NR_HUGE);
72 for (Geom::Crossings::const_iterator i = cs.begin(); i != cs.end(); i++) {
73 Geom::Point p_ix = this->_curve->pointAt((*i).ta);
74 Geom::Coord dist = Geom::distance(p_ix, p);
76 // Test if we have two segments (curves) from the same path..
77 if (this->_num_path == curve._num_path) {
78 // Never try to intersect a segment with itself
79 if (this->_num_segm == curve._num_segm) continue;
80 // Two subsequent segments (curves) in a path will have a common node; this node is not considered to be an intersection
81 if (this->_num_segm == curve._num_segm + 1 && (*i).ta == 0 && (*i).tb == 1) continue;
82 if (this->_num_segm + 1 == curve._num_segm && (*i).ta == 1 && (*i).tb == 0) continue;
83 }
85 if (dist < best_dist) {
86 best_dist = dist;
87 best_p = p_ix;
88 }
89 }
91 // Now we've found the closest intersection, return it as a SnappedPoint
92 bool const use_this_as_primary = _distance < curve.getSnapDistance();
93 Inkscape::SnappedCurve const *primaryC = use_this_as_primary ? this : &curve;
94 Inkscape::SnappedCurve const *secondaryC = use_this_as_primary ? &curve : this;
96 // The intersection should in fact be returned in desktop coordinates
97 best_p = best_p * dt2doc;
99 Geom::Coord primaryDist = use_this_as_primary ? Geom::L2(best_p - this->getPoint()) : Geom::L2(best_p - curve.getPoint());
100 Geom::Coord secondaryDist = use_this_as_primary ? Geom::L2(best_p - curve.getPoint()) : Geom::L2(best_p - this->getPoint());
101 // TODO: Investigate whether it is possible to use document coordinates everywhere
102 // in the snapper code. Only the mouse position should be in desktop coordinates, I guess.
103 // All paths are already in document coords and we are certainly not going to change THAT.
104 return SnappedPoint(best_p, Inkscape::SNAPSOURCE_UNDEFINED, primaryC->getSourceNum(), Inkscape::SNAPTARGET_PATH_INTERSECTION, primaryDist, primaryC->getTolerance(), primaryC->getAlwaysSnap(), true, false, true,
105 secondaryDist, secondaryC->getTolerance(), secondaryC->getAlwaysSnap());
106 }
108 // No intersection
109 return SnappedPoint(Geom::Point(NR_HUGE, NR_HUGE), SNAPSOURCE_UNDEFINED, 0, SNAPTARGET_UNDEFINED, NR_HUGE, 0, false, false, false, false, NR_HUGE, 0, false);
110 }
112 // search for the closest snapped line
113 bool getClosestCurve(std::list<Inkscape::SnappedCurve> const &list, Inkscape::SnappedCurve &result)
114 {
115 bool success = false;
117 for (std::list<Inkscape::SnappedCurve>::const_iterator i = list.begin(); i != list.end(); i++) {
118 if ((i == list.begin()) || (*i).getSnapDistance() < result.getSnapDistance()) {
119 result = *i;
120 success = true;
121 }
122 }
124 return success;
125 }
127 // search for the closest intersection of two snapped curves, which are both member of the same collection
128 bool getClosestIntersectionCS(std::list<Inkscape::SnappedCurve> const &list, Geom::Point const &p, Inkscape::SnappedPoint &result, Geom::Matrix dt2doc)
129 {
130 bool success = false;
132 for (std::list<Inkscape::SnappedCurve>::const_iterator i = list.begin(); i != list.end(); i++) {
133 if ((*i).getTarget() != Inkscape::SNAPTARGET_BBOX_EDGE) { // We don't support snapping to intersections of bboxes,
134 // as this would require two bboxes two be flashed in the snap indicator
135 std::list<Inkscape::SnappedCurve>::const_iterator j = i;
136 j++;
137 for (; j != list.end(); j++) {
138 if ((*j).getTarget() != Inkscape::SNAPTARGET_BBOX_EDGE) { // We don't support snapping to intersections of bboxes
139 Inkscape::SnappedPoint sp = (*i).intersect(*j, p, dt2doc);
140 if (sp.getAtIntersection()) {
141 // if it's the first point
142 bool const c1 = !success;
143 // or, if it's closer
144 bool const c2 = sp.getSnapDistance() < result.getSnapDistance();
145 // or, if it's just as close then look at the other distance
146 // (only relevant for snapped points which are at an intersection)
147 bool const c3 = (sp.getSnapDistance() == result.getSnapDistance()) && (sp.getSecondSnapDistance() < result.getSecondSnapDistance());
148 // then prefer this point over the previous one
149 if (c1 || c2 || c3) {
150 result = sp;
151 success = true;
152 }
153 }
154 }
155 }
156 }
157 }
159 return success;
160 }
161 /*
162 Local Variables:
163 mode:c++
164 c-file-style:"stroustrup"
165 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
166 indent-tabs-mode:nil
167 fill-column:99
168 End:
169 */
170 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :