ConvexHull.h

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/*
 * $Revision: 2299 $
 *
 * last checkin:
 *   $Author: gutwenger $
 *   $Date: 2012-05-07 15:57:08 +0200 (Mon, 07 May 2012) $
 ***************************************************************/

#ifdef _MSC_VER
#pragma once
#endif

#ifndef OGDF_CONVEX_HULL_H
#define OGDF_CONVEX_HULL_H

#include <ogdf/basic/GraphAttributes.h>
#include <ogdf/basic/geometry.h>
#include <ogdf/internal/energybased/MultilevelGraph.h>
#include <vector>

namespace ogdf {

// all returned Polygons are clockwise (cw)
class OGDF_EXPORT ConvexHull {
private:
    bool sameDirection(const DPoint &start, const DPoint &end, const DPoint &s, const DPoint &e) const;

    // calculates a convex hull very quickly but only works with cross-free Polygons!
    DPolygon conv(const DPolygon &poly) const;

    // Calculates the Part of the convex hull that is left of line start-end
    // /a points should only contain points that really are left of the line.
    void leftHull(std::vector<DPoint> points, DPoint &start, DPoint &end, DPolygon &hullPoly) const;


public:
    ConvexHull();
    ~ConvexHull();

    DPoint calcNormal(const DPoint &start, const DPoint &end) const;
    double leftOfLine(const DPoint &normal, const DPoint &point, const DPoint &pointOnLine) const;

    DPolygon call(std::vector<DPoint> points) const;
    DPolygon call(GraphAttributes &GA) const;
    DPolygon call(MultilevelGraph &MLG) const;

};

} // namespace ogdf

#endif