Polygon Class Reference

A 2D polygon defined by an ordered list of vertices. More...

#include <polygon.h>

Public Member Functions
	Polygon ()
	Default constructor — creates an empty (invalid) polygon.
void	appendPoint (const Point &point)
	Append a vertex to the polygon.
double	area () const
	Compute the area of the polygon using the shoelace formula.
void	move (double bearing, double distance)
	Move all vertices by a bearing and distance.
void	rotate (const Point &centroid, double angle)
	Rotate all vertices around a centroid by an angle.
Point	centroid () const
	Compute the centroid (geometric centre) of the polygon.
bool	contains (const Point &point) const
	Test whether a point lies inside the polygon.
Line::List	lines () const
	Return the edges of the polygon as a list of lines.
Rectangle	boundingRectangle () const
	Return the bounding rectangle of this polygon.
bool	isValid () const
	Test whether this polygon has at least 3 vertices.

Static Public Member Functions
static Polygon	fromLine (const Line &line, int expandBy)
	Construct a rectangle-shaped polygon from a line expanded by a width.

Detailed Description

A 2D polygon defined by an ordered list of vertices.

Represents a 2D polygon as an ordered list of Point vertices.

Provides area, centroid, containment, and movement operations.

Definition at line 14 of file polygon.h.

Constructor & Destructor Documentation

Polygon()

Polygon::Polygon ( )

inline

Default constructor — creates an empty (invalid) polygon.

Definition at line 18 of file polygon.h.

Member Function Documentation

appendPoint()

void Polygon::appendPoint ( const Point &  point )

inline

Append a vertex to the polygon.

Parameters

point

Vertex to add

Definition at line 32 of file polygon.h.

area()

double Polygon::area

(

)

const

Compute the area of the polygon using the shoelace formula.

Returns

Signed area (positive for counter-clockwise winding)

boundingRectangle()

Rectangle Polygon::boundingRectangle

(

)

const

Return the bounding rectangle of this polygon.

Returns

Smallest Rectangle enclosing all vertices

centroid()

Point Polygon::centroid

(

)

const

Compute the centroid (geometric centre) of the polygon.

Returns

Centroid Point

contains()

bool Polygon::contains

(

const Point &

point

)

const

Test whether a point lies inside the polygon.

Parameters

point

Point to test

Returns

true if the point is inside the polygon boundary

fromLine()

static Polygon Polygon::fromLine ( const Line &  line, int  expandBy  )

static

Construct a rectangle-shaped polygon from a line expanded by a width.

Parameters

line	Centre line of the polygon
expandBy	Half-width of the resulting rectangular polygon

Returns

Rectangular Polygon centred on the line

isValid()

bool Polygon::isValid ( ) const

inline

Test whether this polygon has at least 3 vertices.

Returns

true if the polygon has enough vertices to be valid

Definition at line 83 of file polygon.h.

lines()

Line::List Polygon::lines

(

)

const

Return the edges of the polygon as a list of lines.

Returns

Line list connecting consecutive vertices

move()

void Polygon::move	(	double	bearing,
		double	distance
	)

Move all vertices by a bearing and distance.

Parameters

bearing	Direction of movement in degrees
distance	Distance to move

rotate()

void Polygon::rotate	(	const Point &	centroid,
		double	angle
	)

Rotate all vertices around a centroid by an angle.

Parameters

centroid	Centre of rotation
angle	Rotation angle in degrees

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The documentation for this class was generated from the following file:

• include/Kanoop/geometry/polygon.h