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#include "libnr/nr-values.h"
#include "libnr/nr-point-fns.h"
#include "geom.h"
#include "line-snapper.h"
Inkscape::LineSnapper::LineSnapper(SPNamedView const *nv, NR::Coord const d) : Snapper(nv, d)
{
}
Inkscape::SnappedPoint Inkscape::LineSnapper::_doFreeSnap(Inkscape::Snapper::PointType const &t,
NR::Point const &p,
bool const &f,
std::vector<NR::Point> &points_to_snap,
std::list<SPItem const *> const &it) const
{
/* Snap along x (ie to vertical lines) */
Inkscape::SnappedPoint const v = _doConstrainedSnap(t, p, f, points_to_snap, component_vectors[NR::X], it);
/* Snap along y (ie to horizontal lines) */
Inkscape::SnappedPoint const h = _doConstrainedSnap(t, p, f, points_to_snap, component_vectors[NR::Y], it);
/* If we snapped to both, combine the two results. This is so that, for example,
** we snap nicely to the intersection of two guidelines.
*/
if (v.getDistance() < NR_HUGE && h.getDistance() < NR_HUGE) {
return SnappedPoint(NR::Point(v.getPoint()[NR::X], h.getPoint()[NR::Y]), hypot(v.getDistance(), h.getDistance()));
}
/* If we snapped to a vertical line, return that */
if (v.getDistance() < NR_HUGE) {
return v;
}
/* Otherwise just return any horizontal snap; if we didn't snap to that either
** we haven't snapped to anything.
*/
return h;
}
Inkscape::SnappedPoint Inkscape::LineSnapper::_doConstrainedSnap(Inkscape::Snapper::PointType const &t,
NR::Point const &p,
bool const &f,
std::vector<NR::Point> &points_to_snap,
ConstraintLine const &c,
std::list<SPItem const *> const &it) const
{
Inkscape::SnappedPoint s = SnappedPoint(p, NR_HUGE);
/* Get the lines that we will try to snap to */
const LineList lines = _getSnapLines(p);
for (LineList::const_iterator i = lines.begin(); i != lines.end(); i++) {
/* Normal to the line we're trying to snap along */
NR::Point const n(NR::rot90(NR::unit_vector(c.getDirection())));
/* Constant term of the line we're trying to snap along */
NR::Coord const q = dot(n, c.hasPoint() ? c.getPoint() : p);
/* Try to intersect this line with the target line */
NR::Point t = p;
IntersectorKind const k = intersector_line_intersection(n, q, component_vectors[i->first], i->second, t);
if (k == INTERSECTS) {
const NR::Coord dist = L2(t - p);
if (dist < getDistance() && dist < s.getDistance() ) {
s = SnappedPoint(t, dist);
}
}
}
return s;
}
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :
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