void Inkscape::ObjectSnapper::_snapPathsConstrained(IntermSnapResults &isr,
SnapCandidatePoint const &p,
SnapConstraint const &c,
Geom::Point const &p_proj_on_constraint) const
{
_collectPaths(p_proj_on_constraint, p.getSourceType(), p.getSourceNum() <= 0);
// Now we can finally do the real snapping, using the paths collected above
SPDesktop const *dt = _snapmanager->getDesktop();
g_assert(dt != NULL);
Geom::Point direction_vector = c.getDirection();
if (!is_zero(direction_vector)) {
direction_vector = Geom::unit_vector(direction_vector);
}
// The intersection point of the constraint line with any path, must lie within two points on the
// SnapConstraint: p_min_on_cl and p_max_on_cl. The distance between those points is twice the snapping tolerance
Geom::Point const p_min_on_cl = dt->dt2doc(p_proj_on_constraint - getSnapperTolerance() * direction_vector);
Geom::Point const p_max_on_cl = dt->dt2doc(p_proj_on_constraint + getSnapperTolerance() * direction_vector);
Geom::Coord tolerance = getSnapperTolerance();
// PS: Because the paths we're about to snap to are all expressed relative to document coordinate system, we will have
// to convert the snapper coordinates from the desktop coordinates to document coordinates
std::vector<Geom::Path> constraint_path;
if (c.isCircular()) {
Geom::Circle constraint_circle(dt->dt2doc(c.getPoint()), c.getRadius());
constraint_circle.getPath(constraint_path);
} else {
Geom::Path constraint_line;
constraint_line.start(p_min_on_cl);
constraint_line.appendNew<Geom::LineSegment>(p_max_on_cl);
constraint_path.push_back(constraint_line);
}
// Length of constraint_path will always be one
bool strict_snapping = _snapmanager->snapprefs.getStrictSnapping();
// Find all intersections of the constrained path with the snap target candidates
std::vector<Geom::Point> intersections;
for (std::vector<SnapCandidatePath >::const_iterator k = _paths_to_snap_to->begin(); k != _paths_to_snap_to->end(); ++k) {
if (k->path_vector && _allowSourceToSnapToTarget(p.getSourceType(), (*k).target_type, strict_snapping)) {
// Do the intersection math
Geom::CrossingSet cs = Geom::crossings(constraint_path, *(k->path_vector));
// Store the results as intersection points
unsigned int index = 0;
for (Geom::CrossingSet::const_iterator i = cs.begin(); i != cs.end(); ++i) {
if (index >= constraint_path.size()) {
break;
}
// Reconstruct and store the points of intersection
for (Geom::Crossings::const_iterator m = (*i).begin(); m != (*i).end(); ++m) {
intersections.push_back(constraint_path[index].pointAt((*m).ta));
}
index++;
}
//Geom::crossings will not consider the closing segment apparently, so we'll handle that separately here
//TODO: This should have been fixed in rev. #9859, which makes this workaround obsolete
for(Geom::PathVector::iterator it_pv = k->path_vector->begin(); it_pv != k->path_vector->end(); ++it_pv) {
if (it_pv->closed()) {
// Get the closing linesegment and convert it to a path
Geom::Path cls;
cls.close(false);
cls.append(it_pv->back_closed());
// Intersect that closing path with the constrained path
Geom::Crossings cs = Geom::crossings(constraint_path.front(), cls);
// Reconstruct and store the points of intersection
index = 0; // assuming the constraint path vector has only one path
for (Geom::Crossings::const_iterator m = cs.begin(); m != cs.end(); ++m) {
intersections.push_back(constraint_path[index].pointAt((*m).ta));
}
}
}
// Convert the collected points of intersection to snapped points
for (std::vector<Geom::Point>::iterator p_inters = intersections.begin(); p_inters != intersections.end(); ++p_inters) {
// Convert to desktop coordinates
(*p_inters) = dt->doc2dt(*p_inters);
// Construct a snapped point
Geom::Coord dist = Geom::L2(p.getPoint() - *p_inters);
SnappedPoint s = SnappedPoint(*p_inters, p.getSourceType(), p.getSourceNum(), k->target_type, dist, getSnapperTolerance(), getSnapperAlwaysSnap(), true, k->target_bbox);;
// Store the snapped point
if (dist <= tolerance) { // If the intersection is within snapping range, then we might snap to it
isr.points.push_back(s);
}
}
}
}
}
void SPShape::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const {
if (this->_curve == NULL) {
return;
}
Geom::PathVector const &pathv = this->_curve->get_pathvector();
if (pathv.empty()) {
return;
}
Geom::Affine const i2dt (this->i2dt_affine ());
if (snapprefs->isTargetSnappable(Inkscape::SNAPTARGET_OBJECT_MIDPOINT)) {
Geom::OptRect bbox = this->desktopVisualBounds();
if (bbox) {
p.push_back(Inkscape::SnapCandidatePoint(bbox->midpoint(), Inkscape::SNAPSOURCE_OBJECT_MIDPOINT, Inkscape::SNAPTARGET_OBJECT_MIDPOINT));
}
}
for(Geom::PathVector::const_iterator path_it = pathv.begin(); path_it != pathv.end(); ++path_it) {
if (snapprefs->isTargetSnappable(Inkscape::SNAPTARGET_NODE_CUSP)) {
// Add the first point of the path
p.push_back(Inkscape::SnapCandidatePoint(path_it->initialPoint() * i2dt, Inkscape::SNAPSOURCE_NODE_CUSP, Inkscape::SNAPTARGET_NODE_CUSP));
}
Geom::Path::const_iterator curve_it1 = path_it->begin(); // incoming curve
Geom::Path::const_iterator curve_it2 = ++(path_it->begin()); // outgoing curve
while (curve_it1 != path_it->end_default())
{
// For each path: consider midpoints of line segments for snapping
if (snapprefs->isTargetSnappable(Inkscape::SNAPTARGET_LINE_MIDPOINT)) {
if (Geom::LineSegment const* line_segment = dynamic_cast<Geom::LineSegment const*>(&(*curve_it1))) {
p.push_back(Inkscape::SnapCandidatePoint(Geom::middle_point(*line_segment) * i2dt, Inkscape::SNAPSOURCE_LINE_MIDPOINT, Inkscape::SNAPTARGET_LINE_MIDPOINT));
}
}
if (curve_it2 == path_it->end_default()) { // Test will only pass for the last iteration of the while loop
if (snapprefs->isTargetSnappable(Inkscape::SNAPTARGET_NODE_CUSP) && !path_it->closed()) {
// Add the last point of the path, but only for open paths
// (for closed paths the first and last point will coincide)
p.push_back(Inkscape::SnapCandidatePoint((*curve_it1).finalPoint() * i2dt, Inkscape::SNAPSOURCE_NODE_CUSP, Inkscape::SNAPTARGET_NODE_CUSP));
}
} else {
/* Test whether to add the node between curve_it1 and curve_it2.
* Loop to end_default (so only iterating through the stroked part); */
Geom::NodeType nodetype = Geom::get_nodetype(*curve_it1, *curve_it2);
bool c1 = snapprefs->isTargetSnappable(Inkscape::SNAPTARGET_NODE_CUSP) && (nodetype == Geom::NODE_CUSP || nodetype == Geom::NODE_NONE);
bool c2 = snapprefs->isTargetSnappable(Inkscape::SNAPTARGET_NODE_SMOOTH) && (nodetype == Geom::NODE_SMOOTH || nodetype == Geom::NODE_SYMM);
if (c1 || c2) {
Inkscape::SnapSourceType sst;
Inkscape::SnapTargetType stt;
switch (nodetype) {
case Geom::NODE_CUSP:
sst = Inkscape::SNAPSOURCE_NODE_CUSP;
stt = Inkscape::SNAPTARGET_NODE_CUSP;
break;
case Geom::NODE_SMOOTH:
case Geom::NODE_SYMM:
sst = Inkscape::SNAPSOURCE_NODE_SMOOTH;
stt = Inkscape::SNAPTARGET_NODE_SMOOTH;
break;
default:
sst = Inkscape::SNAPSOURCE_UNDEFINED;
stt = Inkscape::SNAPTARGET_UNDEFINED;
break;
}
p.push_back(Inkscape::SnapCandidatePoint(curve_it1->finalPoint() * i2dt, sst, stt));
}
}
++curve_it1;
++curve_it2;
}
// Find the internal intersections of each path and consider these for snapping
// (using "Method 1" as described in Inkscape::ObjectSnapper::_collectNodes())
if (snapprefs->isTargetSnappable(Inkscape::SNAPTARGET_PATH_INTERSECTION) || snapprefs->isSourceSnappable(Inkscape::SNAPSOURCE_PATH_INTERSECTION)) {
Geom::Crossings cs;
try {
cs = self_crossings(*path_it); // This can be slow!
if (!cs.empty()) { // There might be multiple intersections...
for (Geom::Crossings::const_iterator i = cs.begin(); i != cs.end(); ++i) {
Geom::Point p_ix = (*path_it).pointAt((*i).ta);
p.push_back(Inkscape::SnapCandidatePoint(p_ix * i2dt, Inkscape::SNAPSOURCE_PATH_INTERSECTION, Inkscape::SNAPTARGET_PATH_INTERSECTION));
}
}
} catch (Geom::RangeError &e) {
// do nothing
// The exception could be Geom::InfiniteSolutions: then no snappoints should be added
}
}
}
}