#include <visp3/core/vpPolygon.h>

Public Types
enum	PointInPolygonMethod { PnPolySegmentIntersection, PnPolyRayCasting }

Public Member Functions
	vpPolygon ()

	vpPolygon (const std::vector< vpImagePoint > &corners)

	vpPolygon (const std::list< vpImagePoint > &corners)

	vpPolygon (const vpPolygon &poly)

virtual	~vpPolygon ()

vpPolygon &	operator= (const vpPolygon &poly)

void	buildFrom (const std::vector< vpImagePoint > &corners)

void	buildFrom (const std::list< vpImagePoint > &corners)

void	buildFrom (const std::vector< vpPoint > &corners, const vpCameraParameters &cam)

unsigned int	getSize () const

void	initClick (const vpImage< unsigned char > &I)

bool	isInside (const vpImagePoint &iP, const PointInPolygonMethod &method=PnPolyRayCasting) const

void	display (const vpImage< unsigned char > &I, const vpColor &color, unsigned int thickness=1) const

const std::vector< vpImagePoint > &	getCorners () const

double	getArea () const

vpImagePoint	getCenter () const

vpRect	getBoundingBox () const

Static Public Member Functions
static bool	isInside (const std::vector< vpImagePoint > &roi, const double &i, const double &j, const PointInPolygonMethod &method=PnPolyRayCasting)

Protected Member Functions
void	init (const std::vector< vpImagePoint > &corners)

void	init (const std::list< vpImagePoint > &corners)

void	updateArea ()

void	updateCenter ()

void	updateBoundingBox ()

Protected Attributes
std::vector< vpImagePoint >	_corners

vpImagePoint	_center

double	_area

bool	_goodPoly

vpRect	_bbox

Detailed Description

Defines a generic 2D polygon.

A polygon is internally represented by N 2D points.

By default three coordinates in the $ (i,j) $ frame (see vpImagePoint class documentation for more details about the frame) are used $ (0,0) $ , $ (1,0) $ and $ (0,1) $ .

The code bellow shows how to manipulate a polygon.

#include <iostream>
#include <visp3/core/vpPolygon.h>
int main()
{
  std::vector<vpImagePoint> corners;
  // Initialize the corners vector with 4 points
  corners.push_back( vpImagePoint( 50, 100) );
  corners.push_back( vpImagePoint( 50, 300) );
  corners.push_back( vpImagePoint(200, 300) );
  corners.push_back( vpImagePoint(200, 100) );
  // Initialize a polygon with the corners
  vpPolygon polygon(corners);
  // Get the polygon bounding box
  vpRect bbox = polygon.getBoundingBox();
  std::cout << "Bounding box: " << bbox.getTopLeft() << " to " << bbox.getBottomRight() << std::endl;
  // Get the polygon surface and center
  std::cout << "Area: " << polygon.getArea() << std::endl;
  std::cout << "Center: " << polygon.getCenter() << std::endl;
  // Check if a point is inside the polygon
  vpImagePoint ip(550, 200);
  std::cout << "The point " << ip << " is " << (polygon.isInside(ip) ? "inside":"outside") << " the polygon" << std::endl;
  return 0;
}

Definition at line 99 of file vpPolygon.h.

Member Enumeration Documentation

enum vpPolygon::PointInPolygonMethod

Enumerator
PnPolySegmentIntersection	Legacy Point In Polygon test.
PnPolyRayCasting	Point In Polygon test using ray casting method (faster).

Definition at line 114 of file vpPolygon.h.

Constructor & Destructor Documentation

vpPolygon::vpPolygon ( )

Basic constructor.

By default, it defines a triangle with the three 2D points coordinates : $ (0,0) $ , $ (1,0) $ and $ (0,1) $ .

Definition at line 55 of file vpPolygon.cpp.

References init().

vpPolygon::vpPolygon ( const std::vector< vpImagePoint > & corners )

Constructor which initialises the polygon thanks to the given corners.

Warning: the corners must be ordered (either clockwise or counter clockwise).

Parameters

corners : The Points defining the corners.

Definition at line 72 of file vpPolygon.cpp.

References _goodPoly, and init().

vpPolygon::vpPolygon ( const std::list< vpImagePoint > & corners )

Constructor which initialises the polygon thanks to the given corners.

Warning: the corners must be ordered (either clockwise or counter clockwise).

Parameters

corners : The Points defining the corners.

Definition at line 88 of file vpPolygon.cpp.

References _goodPoly, and init().

vpPolygon::vpPolygon ( const vpPolygon & poly )

Copy constructor

Parameters

poly	: The polygon used for the initialisation.

Definition at line 102 of file vpPolygon.cpp.

References _area, _bbox, _center, _corners, and _goodPoly.

vpPolygon::~vpPolygon ( )

virtual

Basic destructor

Definition at line 117 of file vpPolygon.cpp.

Member Function Documentation

void vpPolygon::buildFrom ( const std::vector< vpImagePoint > & corners )

Initialises the triangle thanks to the collection of 2D points (in pixel).

Warning: the corners must be ordered (either clockwise or counter clockwise).

Parameters

corners : The corners of the polyon.

Definition at line 147 of file vpPolygon.cpp.

References init().

Referenced by buildFrom(), and initClick().

void vpPolygon::buildFrom ( const std::list< vpImagePoint > & corners )

Initialises the polygon thanks to the collection of 2D points (in pixel).

Warning: the corners must be ordered (either clockwise or counter clockwise).

Parameters

corners : The corners of the polyon.

Definition at line 160 of file vpPolygon.cpp.

References init().

void vpPolygon::buildFrom	(	const std::vector< vpPoint > &	corners,
		const vpCameraParameters &	cam
	)

Initialises the triangle thanks to the collection of 2D points (in meter). The fields x and y are used to compute the corresponding coordinates in pixel thanks to the camera parameters cam.

Warning: the corners must be ordered (either clockwise or counter clockwise).

Parameters

corners	: The corners of the polyon.
cam	: The camera parameters used to convert the coordinates from meter to pixel.

Definition at line 177 of file vpPolygon.cpp.

References buildFrom(), and vpMeterPixelConversion::convertPoint().

void vpPolygon::display	(	const vpImage< unsigned char > &	I,
		const vpColor &	color,
		unsigned int	thickness = `1`
	)		const

Display the polygon in the image (overlay, so the image is not modified). A call to the flush() method is necessary.

Parameters

I	: The image where the polygon is displayed.
color	: The color of the polygon's lines.
thickness	: The thickness of the polygon's lines.

Definition at line 517 of file vpPolygon.cpp.

References _corners, and vpDisplay::displayLine().

double vpPolygon::getArea ( ) const

inline

Return the area of the polygon. The area is computed when the polygon is built from the corners.

Returns: The area of the polygon.

Definition at line 154 of file vpPolygon.h.

Referenced by vpMbtPolygon::isVisible().

vpRect vpPolygon::getBoundingBox ( ) const

inline

Return the bounding box. The bounding box is the smallest rectangle containing all the polygon.

Returns: The bounding box of the polygon.

Definition at line 174 of file vpPolygon.h.

Referenced by vpKeyPoint::matchPointAndDetect().

vpImagePoint vpPolygon::getCenter ( ) const

inline

Return the center of the polygon. The center is computed when the polygon is built from the corners.

Returns: The area of the polygon.

Definition at line 164 of file vpPolygon.h.

const std::vector<vpImagePoint>& vpPolygon::getCorners ( ) const

inline

Get the corners of the polygon.

Returns: A reference to the corners.

Definition at line 143 of file vpPolygon.h.

unsigned int vpPolygon::getSize ( ) const

Return number of corners belonging to the polygon.

Definition at line 566 of file vpPolygon.cpp.

References _corners.

void vpPolygon::init ( const std::vector< vpImagePoint > & corners )

protected

Intialises the polygon using the collection of image points. This method computes some internal variables such as center, area, ...

Warning: the corners must be ordered (either clockwise or counter clockwise).

Parameters

corners : The corners of the polygon.

Definition at line 222 of file vpPolygon.cpp.

References _corners, updateArea(), updateBoundingBox(), and updateCenter().

Referenced by buildFrom(), and vpPolygon().

void vpPolygon::init ( const std::list< vpImagePoint > & corners )

protected

Intialises the polygon using the collection of image points. This method computes some internal variables such as center, area, ...

Warning: the corners must be ordered (either clockwise or counter clockwise).

Parameters

corners : The corners of the polygon.

Definition at line 243 of file vpPolygon.cpp.

References _corners, updateArea(), updateBoundingBox(), and updateCenter().

void vpPolygon::initClick ( const vpImage< unsigned char > & I )

Initialises the polygon by (left-)clicking to add a corners to the polygon. A right click is used to stop the addition of new corners.

Parameters

I	: The image where to click to initialise the corners.

Definition at line 193 of file vpPolygon.cpp.

References buildFrom(), vpMouseButton::button1, vpDisplay::displayCross(), vpDisplay::flush(), vpDisplay::getClick(), and vpColor::red.

bool vpPolygon::isInside	(	const vpImagePoint &	ip,
		const PointInPolygonMethod &	method = `PnPolyRayCasting`
	)		const

Check if the 2D point $ ip $ is inside the polygon.

Parameters

ip	: The point which have to be tested.
method	: Method to use for Point In Polygon test.

Returns: Returns true if the point is inside the polygon, false otherwise.

Definition at line 303 of file vpPolygon.cpp.

References _corners, vpImagePoint::get_i(), vpImagePoint::get_j(), vpImagePoint::get_u(), vpImagePoint::get_v(), PnPolyRayCasting, PnPolySegmentIntersection, vpImagePoint::set_i(), and vpImagePoint::set_j().

Referenced by vpKeyPoint::compute3DForPointsOnCylinders(), vpMbtDistanceKltPoints::init(), vpMbtDistanceKltCylinder::init(), isInside(), vpMbtDistanceKltPoints::updateMask(), and vpMbtDistanceKltCylinder::updateMask().

bool vpPolygon::isInside	(	const std::vector< vpImagePoint > &	roi,
		const double &	i,
		const double &	j,
		const PointInPolygonMethod &	method = `PnPolyRayCasting`
	)

static

Test if an image point is inside a 2D polygon.

Parameters

roi	: List of the polygon corners.
i	: i-coordinate of the image point to test.
j	: j-coordinate of the image point to test.
method	: Method to use for Point In Polygon test.