DPolygon2 Class Reference

List of all members.

Public Member Functions
unsigned int	NumTotalVertices () const
bool	ComputeExtents (DRECT &rect) const
bool	ContainsPoint (const DPoint2 &p) const
void	GetAsDLine2 (DLine2 &dline) const
int	WhichRing (int &iVtxNum) const
void	NearestPoint (const DPoint2 &Point, int &iIndex, double &dist) const
bool	NearestSegment (const DPoint2 &Point, int &iIndex, double &dist, DPoint2 &Intersection) const
void	Add (const DPoint2 &p)
void	Mult (double factor)
void	ReverseOrder ()
void	InsertPointAfter (int iInsertAfter, const DPoint2 &Point)
void	RemovePoint (int N)
int	RemoveDegeneratePoints (double dEpsilon)

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Detailed Description

We represent a polygon as a collection of closed rings, each of which is represented by a DLine2. The first DLine2 is the 'outside' ring, any subsequent DLine2 are 'inside' rings, which are holes.

In most usage, there should be a consistency in the vertex ordering: the 'outside' ring should be counter-clockwise, and the 'inside' ring(s) should be clockwise.

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Member Function Documentation

void DPolygon2::Add (  const DPoint2 &  p  )

Add the given amount to all coordinates of the polygon. Spatially, this offsets the location of the polygon.

void DPolygon2::GetAsDLine2 (  DLine2 &  dline  )  const

Normally the polygon is stored as a series of rings. Sometimes it is necessary to access the polygon as a single array of points instead. This method fills a provided DLine2 with all the points of all rings of the polygon.

void DPolygon2::InsertPointAfter (  int  iInsertAfter, const DPoint2 &  Point )

The insertion point can be on the outer ring, or any inner ring.

void DPolygon2::Mult (  double  factor  )

Multiplies (scales) all the coordinates of the polygon.

void DPolygon2::NearestPoint (  const DPoint2 &  Point, int &  iIndex, double &  dClosest )  const

Return the nearest point (of the points which make up the line). This is not the same as the closest place on the line, which may lie between the defining points; use NearestSegment to find that. Parameters: Point  The input point. iIndex  Index of the first point of the nearest line segment. dClosest  Distance from the DLine2 to the input point.

bool DPolygon2::NearestSegment (  const DPoint2 &  Point, int &  iIndex, double &  dist, DPoint2 &  Intersection )  const

Returns the location of the closest point on the polygon to a given point. Parameters: Point  The input point. iIndex  Index of the first point of the nearest line segment. dist  Distance from the DPolygon2 to the input point. Intersection  The closest point on the DPolygon2. Returns: True if a closest point was found.

void DPolygon2::RemovePoint (  int  N  )

The Nth point can be on the outer ring, or any inner ring.

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