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#include "libnr/nr-point-fns.h"
Geom::Point
snap_vector_midpoint (Geom::Point const &p, Geom::Point const &begin, Geom::Point const &end, double snap)
{
double length = Geom::distance(begin, end);
Geom::Point be = (end - begin) / length;
double r = Geom::dot(p - begin, be);
if (r < 0.0) return begin;
if (r > length) return end;
double snapdist = length * snap;
double r_snapped = (snap==0) ? r : floor(r/(snapdist + 0.5)) * snapdist;
return (begin + r_snapped * be);
}
double
get_offset_between_points (Geom::Point const &p, Geom::Point const &begin, Geom::Point const &end)
{
double length = Geom::distance(begin, end);
Geom::Point be = (end - begin) / length;
double r = Geom::dot(p - begin, be);
if (r < 0.0) return 0.0;
if (r > length) return 1.0;
return (r / length);
}
Geom::Point
project_on_linesegment(Geom::Point const &p, Geom::Point const &p1, Geom::Point const &p2)
{
// p_proj = projection of p on the linesegment running from p1 to p2
// p_proj = p1 + u (p2 - p1)
// calculate u according to "Minimum Distance between a Point and a Line"
// see http://local.wasp.uwa.edu.au/~pbourke/geometry/pointline/
// Warning: projected points will not necessarily be in between the endpoints of the linesegments!
if (p1 == p2) { // to avoid div. by zero below
return p;
}
Geom::Point d1(p-p1); // delta 1
Geom::Point d2(p2-p1); // delta 2
double u = Geom::dot(d1, d2) / Geom::L2sq(d2);
return (p1 + u*(p2-p1));
}
/*
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:fileencoding=utf-8:textwidth=99 :
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