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/*
* Routines for dealing with lines (intersections, etc.)
*
* Authors:
* Maximilian Albert <Anhalter42@gmx.de>
*
* Copyright (C) 2007 authors
*
* Released under GNU GPL, read the file 'COPYING' for more information
*/
#ifndef SEEN_LINE_GEOMETRY_H
#define SEEN_LINE_GEOMETRY_H
#include "libnr/nr-point.h"
#include "libnr/nr-point-fns.h"
#include "libnr/nr-maybe.h"
#include "glib.h"
#include "display/sp-ctrlline.h"
#include "axis-manip.h" // FIXME: This is only for Box3D::epsilon; move that to a better location
#include "document.h"
#include "ui/view/view.h"
namespace Box3D {
class Line {
public:
Line(NR::Point const &start, NR::Point const &vec, bool is_endpoint = true);
Line(Line const &line);
virtual ~Line() {}
Line &operator=(Line const &line);
virtual NR::Maybe<NR::Point> intersect(Line const &line);
inline NR::Point direction () { return v_dir; }
NR::Point closest_to(NR::Point const &pt); // returns the point on the line closest to pt
friend inline std::ostream &operator<< (std::ostream &out_file, const Line &in_line);
NR::Maybe<NR::Point> intersection_with_viewbox (SPDesktop *desktop);
inline bool lie_on_same_side (NR::Point const &A, NR::Point const &B) {
/* If A is a point in the plane and n is the normal vector of the line then
the sign of dot(A, n) specifies the half-plane in which A lies.
Thus A and B lie on the same side if the dot products have equal sign. */
return ((NR::dot(A, normal) - d0) * (NR::dot(B, normal) - d0)) > 0;
}
double lambda (NR::Point const pt);
inline NR::Point point_from_lambda (double const lambda) {
return (pt + lambda * NR::unit_vector (v_dir)); }
protected:
void set_direction(NR::Point const &dir);
inline static bool pts_coincide (NR::Point const pt1, NR::Point const pt2)
{
return (NR::L2 (pt2 - pt1) < epsilon);
}
NR::Point pt;
NR::Point v_dir;
NR::Point normal;
NR::Coord d0;
};
inline double determinant (NR::Point const &a, NR::Point const &b)
{
return (a[NR::X] * b[NR::Y] - a[NR::Y] * b[NR::X]);
}
std::pair<double, double> coordinates (NR::Point const &v1, NR::Point const &v2, NR::Point const &w);
bool lies_in_sector (NR::Point const &v1, NR::Point const &v2, NR::Point const &w);
bool lies_in_quadrangle (NR::Point const &A, NR::Point const &B, NR::Point const &C, NR::Point const &D, NR::Point const &pt);
std::pair<NR::Point, NR::Point> side_of_intersection (NR::Point const &A, NR::Point const &B,
NR::Point const &C, NR::Point const &D,
NR::Point const &pt, NR::Point const &dir);
/*** For debugging purposes: Draw a knot/node of specified size and color at the given position ***/
void create_canvas_point(NR::Point const &pos, double size = 4.0, guint32 rgba = 0xff00007f);
/*** For debugging purposes: Draw a line between the specified points ***/
void create_canvas_line(NR::Point const &p1, NR::Point const &p2, guint32 rgba = 0xff00007f);
/** A function to print out the Line. It just prints out the coordinates of start point and
direction on the given output stream */
inline std::ostream &operator<< (std::ostream &out_file, const Line &in_line) {
out_file << "Start: " << in_line.pt << " Direction: " << in_line.v_dir;
return out_file;
}
} // namespace Box3D
#endif /* !SEEN_LINE_GEOMETRY_H */
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :
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