src/snapped-line.cpp

   1 /**
   2  *    \file src/snapped-line.cpp
   3  *    \brief SnappedLine 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  */
  10
  11 #include "snapped-line.h"
  12 #include <2geom/geom.h>
  13 #include "libnr/nr-values.h"
  14
  15 Inkscape::SnappedLineSegment::SnappedLineSegment(NR::Point snapped_point, NR::Coord snapped_distance, NR::Point start_point_of_line, NR::Point end_point_of_line)
  16     : _start_point_of_line(start_point_of_line), _end_point_of_line(end_point_of_line)
  17 {
  18         _distance = snapped_distance;
  19         _point = snapped_point;
  20         _at_intersection = false;
  21 }
  22
  23 Inkscape::SnappedLineSegment::SnappedLineSegment()
  24 {
  25         _start_point_of_line = NR::Point(0,0);
  26         _end_point_of_line = NR::Point(0,0);
  27         _distance = NR_HUGE;
  28         _point = NR::Point(0,0);
  29         _at_intersection = false;
  30 }
  31
  32
  33 Inkscape::SnappedLineSegment::~SnappedLineSegment()
  34 {
  35 }
  36
  37 Inkscape::SnappedPoint Inkscape::SnappedLineSegment::intersect(SnappedLineSegment const &line) const
  38 {
  39         Geom::Point intersection_2geom(NR_HUGE, NR_HUGE);
  40         NR::Coord distance = NR_HUGE;
  41
  42         Geom::IntersectorKind result = segment_intersect(_start_point_of_line.to_2geom(), _end_point_of_line.to_2geom(),
  43                                                                          line._start_point_of_line.to_2geom(), line._end_point_of_line.to_2geom(),
  44                                                                          intersection_2geom);
  45         NR::Point intersection(intersection_2geom);
  46
  47         if (result == Geom::intersects) {
  48                 /* The relevant snapped distance is the distance to the closest snapped line, not the
  49                 distance to the intersection. See the comment in Inkscape::SnappedLine::intersect
  50                 */
  51                 distance = std::min(_distance, line.getDistance());
  52         }
  53         return SnappedPoint(intersection, distance, result == Geom::intersects);
  54 };
  55
  56
  57
  58 Inkscape::SnappedLine::SnappedLine(NR::Point snapped_point, NR::Coord snapped_distance, NR::Point normal_to_line, NR::Point point_on_line)
  59     : _normal_to_line(normal_to_line), _point_on_line(point_on_line)
  60 {
  61         _distance = snapped_distance;
  62         _point = snapped_point;
  63         _at_intersection = false;
  64 }
  65
  66 Inkscape::SnappedLine::SnappedLine()
  67 {
  68         _normal_to_line = NR::Point(0,0);
  69         _point_on_line = NR::Point(0,0);
  70         _distance = NR_HUGE;
  71         _point = NR::Point(0,0);
  72         _at_intersection = false;
  73 }
  74
  75 Inkscape::SnappedLine::~SnappedLine()
  76 {
  77 }
  78
  79 Inkscape::SnappedPoint Inkscape::SnappedLine::intersect(SnappedLine const &line) const
  80 {
  81         // Calculate the intersection of to lines, which are both within snapping range
  82         // The point of intersection should be considered for snapping, but might be outside the snapping range
  83
  84         Geom::Point intersection_2geom(NR_HUGE, NR_HUGE);
  85         NR::Coord distance = NR_HUGE;
  86
  87     Geom::IntersectorKind result = Geom::line_intersection(getNormal().to_2geom(), getConstTerm(),
  88                                    line.getNormal().to_2geom(), line.getConstTerm(), intersection_2geom);
  89         NR::Point intersection(intersection_2geom);
  90
  91         if (result == Geom::intersects) {
  92                 /* The relevant snapped distance is the distance to the closest snapped line, not the
  93                 distance to the intersection. For example, when a box is almost aligned with a grid
  94                 in both horizontal and vertical directions, the distance to the intersection of the
  95                 grid lines will always be larger then the distance to a grid line. We will be snapping
  96                 to the closest snapped point however, so if we ever want to snap to the intersection
  97                 then the distance to it should at least be equal to the other distance, not greater
  98                 than it, as that would rule the intersection out
  99                 */
 100                 distance = std::min(_distance, line.getDistance());
 101         }
 102
 103     return SnappedPoint(intersection, distance, result == Geom::intersects);
 104 }
 105
 106 // search for the closest snapped line segment
 107 bool getClosestSLS(std::list<Inkscape::SnappedLineSegment> &list, Inkscape::SnappedLineSegment &result)
 108 {
 109         bool success = false;
 110
 111         for (std::list<Inkscape::SnappedLineSegment>::const_iterator i = list.begin(); i != list.end(); i++) {
 112                 if ((i == list.begin()) || (*i).getDistance() < result.getDistance()) {
 113                         result = *i;
 114                         success = true;
 115                 }
 116         }
 117
 118         return success;
 119 }
 120
 121 // search for the closest intersection of two snapped line segments, which are both member of the same collection
 122 bool getClosestIntersectionSLS(std::list<Inkscape::SnappedLineSegment> &list, Inkscape::SnappedPoint &result)
 123 {
 124         bool success = false;
 125
 126         for (std::list<Inkscape::SnappedLineSegment>::const_iterator i = list.begin(); i != list.end(); i++) {
 127                 std::list<Inkscape::SnappedLineSegment>::const_iterator j = i;
 128                 j++;
 129                 for (; j != list.end(); j++) {
 130                         Inkscape::SnappedPoint sp = (*i).intersect(*j);
 131                         if (sp.getAtIntersection()) {
 132                                 if (!success || sp.getDistance() < result.getDistance()) {
 133                                         // !success because the first intersection cannot be compared to a previous one
 134                                         result = sp;
 135                                         success = true;
 136                                 }
 137                         }
 138                 }
 139         }
 140
 141         return success;
 142 }
 143
 144 // search for the closest snapped line
 145 bool getClosestSL(std::list<Inkscape::SnappedLine> &list, Inkscape::SnappedLine &result)
 146 {
 147         bool success = false;
 148
 149         for (std::list<Inkscape::SnappedLine>::const_iterator i = list.begin(); i != list.end(); i++) {
 150                 if ((i == list.begin()) || (*i).getDistance() < result.getDistance()) {
 151                         result = *i;
 152                         success = true;
 153                 }
 154         }
 155
 156         return success;
 157 }
 158
 159 // search for the closest intersection of two snapped lines, which are both member of the same collection
 160 bool getClosestIntersectionSL(std::list<Inkscape::SnappedLine> &list, Inkscape::SnappedPoint &result)
 161 {
 162         bool success = false;
 163
 164         for (std::list<Inkscape::SnappedLine>::const_iterator i = list.begin(); i != list.end(); i++) {
 165                 std::list<Inkscape::SnappedLine>::const_iterator j = i;
 166                 j++;
 167                 for (; j != list.end(); j++) {
 168                         Inkscape::SnappedPoint sp = (*i).intersect(*j);
 169                         if (sp.getAtIntersection()) {
 170                                 if (!success || sp.getDistance() < result.getDistance()) {
 171                                         // !success because the first intersection cannot be compared to a previous one
 172                                         result = sp;
 173                                         success = true;
 174                                 }
 175                         }
 176                 }
 177         }
 178
 179         return success;
 180 }
 181
 182 // search for the closest intersection of two snapped lines, which are in two different collections
 183 bool getClosestIntersectionSL(std::list<Inkscape::SnappedLine> &list1, std::list<Inkscape::SnappedLine> &list2, Inkscape::SnappedPoint &result)
 184 {
 185         bool success = false;
 186
 187         for (std::list<Inkscape::SnappedLine>::const_iterator i = list1.begin(); i != list1.end(); i++) {
 188                 for (std::list<Inkscape::SnappedLine>::const_iterator j = list2.begin(); j != list2.end(); j++) {
 189                         Inkscape::SnappedPoint sp = (*i).intersect(*j);
 190                         if (sp.getAtIntersection()) {
 191                                 if (!success || sp.getDistance() < result.getDistance()) {
 192                                         // !success because the first intersection cannot be compared to a previous one
 193                                         result = sp;
 194                                         success = true;
 195                                 }
 196                         }
 197                 }
 198         }
 199
 200         return success;
 201 }
 202
 203 /*
 204   Local Variables:
 205   mode:c++
 206   c-file-style:"stroustrup"
 207   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 208   indent-tabs-mode:nil
 209   fill-column:99
 210   End:
 211 */
 212 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :