Line2< T > Class Template Reference

A two dimensional line segment. The line is defined by a start and end point. More...

#include <gz/math/Line2.hh>

Public Member Functions
	Line2 (const math::Vector2< T > &_ptA, const math::Vector2< T > &_ptB)
	Constructor. More...
	Line2 (double _x1, double _y1, double _x2, double _y2)
	Constructor. More...
bool	Collinear (const math::Line2< T > &_line, double _epsilon=1e-6) const
	Check if the given line is collinear with this line. This is the AND of Parallel and Intersect. More...
bool	Collinear (const math::Vector2< T > &_pt, double _epsilon=1e-6) const
	Check if the given point is collinear with this line. More...
double	CrossProduct (const Line2< T > &_line) const
	Return the cross product of this line and the given line. Give 'a' as this line and 'b' as given line, the equation is: (a.start.x - a.end.x) * (b.start.y - b.end.y) - (a.start.y - a.end.y) * (b.start.x - b.end.x) More...
double	CrossProduct (const Vector2< T > &_pt) const
	Return the cross product of this line and the given point. Given 'a' and 'b' as the start and end points, the equation is: More...
bool	Intersect (const Line2< T > &_line, double _epsilon=1e-6) const
	Check if this line intersects the given line segment. More...
bool	Intersect (const Line2< T > &_line, math::Vector2< T > &_pt, double _epsilon=1e-6) const
	Check if this line intersects the given line segment. The point of intersection is returned in the _result parameter. More...
T	Length () const
	Get the length of the line. More...
bool	OnSegment (const math::Vector2< T > &_pt, double _epsilon=1e-6) const
	Return whether the given point is on this line segment. More...
bool	operator!= (const Line2< T > &_line) const
	Inequality operator. More...
bool	operator== (const Line2< T > &_line) const
	Equality operator. More...
math::Vector2< T >	operator[] (size_t _index) const
	Get the start or end point. More...
bool	Parallel (const math::Line2< T > &_line, double _epsilon=1e-6) const
	Check if the given line is parallel with this line. More...
void	Set (const math::Vector2< T > &_ptA, const math::Vector2< T > &_ptB)
	Set the start and end point of the line segment. More...
void	Set (double _x1, double _y1, double _x2, double _y2)
	Set the start and end point of the line segment. More...
double	Slope () const
	Get the slope of the line. More...
bool	Within (const math::Vector2< T > &_pt, double _epsilon=1e-6) const
	Check if the given point is between the start and end points of the line segment. This does not imply that the point is on the segment. More...

Detailed Description

template<typename T>
class gz::math::Line2< T >

A two dimensional line segment. The line is defined by a start and end point.

Constructor & Destructor Documentation

Line2() [1/2]

Line2 ( const math::Vector2< T > &  _ptA, const math::Vector2< T > &  _ptB  )

inline

Constructor.

Parameters

[in]	_ptA	Start point of the line segment
[in]	_ptB	End point of the line segment

References Line2< T >::Set().

Line2() [2/2]

Line2 ( double  _x1, double  _y1, double  _x2, double  _y2  )

inline

Constructor.

Parameters

[in]	_x1	X coordinate of the start point.
[in]	_y1	Y coordinate of the start point.
[in]	_x2	X coordinate of the end point.
[in]	_y2	Y coordinate of the end point.

References Line2< T >::Set().

Member Function Documentation

Collinear() [1/2]

bool Collinear ( const math::Line2< T > &  _line, double  _epsilon = 1e-6  ) const

inline

Check if the given line is collinear with this line. This is the AND of Parallel and Intersect.

Parameters

[in]	_line	The line to check.
[in]	_epsilon	The error bounds within which the collinear check will return true.

Returns

Return true if the line is collinear with this line, false otherwise.

References Line2< T >::Intersect(), and Line2< T >::Parallel().

Collinear() [2/2]

bool Collinear ( const math::Vector2< T > &  _pt, double  _epsilon = 1e-6  ) const

inline

Check if the given point is collinear with this line.

Parameters

[in]	_pt	The point to check.
[in]	_epsilon	The error bounds within which the collinear check will return true.

Returns

Return true if the point is collinear with this line, false otherwise.

References Line2< T >::CrossProduct(), and gz::math::equal().

Referenced by Line2< T >::OnSegment().

CrossProduct() [1/2]

double CrossProduct ( const Line2< T > &  _line ) const

inline

Return the cross product of this line and the given line. Give 'a' as this line and 'b' as given line, the equation is: (a.start.x - a.end.x) * (b.start.y - b.end.y) - (a.start.y - a.end.y) * (b.start.x - b.end.x)

Parameters

[in]

_line

Line for the cross product computation.

Returns

Return the cross product of this line and the given line.

Referenced by Line2< T >::Collinear(), Line2< T >::Intersect(), and Line2< T >::Parallel().

CrossProduct() [2/2]

double CrossProduct ( const Vector2< T > &  _pt ) const

inline

Return the cross product of this line and the given point. Given 'a' and 'b' as the start and end points, the equation is:

Parameters

[in]

_pt

Point for the cross product computation.

Returns

Return the cross product of this line and the given point.

References Vector2< T >::X(), and Vector2< T >::Y().

Intersect() [1/2]

bool Intersect ( const Line2< T > &  _line, double  _epsilon = 1e-6  ) const

inline

Check if this line intersects the given line segment.

Parameters

[in]	_line	The line to check for intersection.
[in]	_epsilon	The error bounds within which the intersection check will return true.

Returns

True if an intersection was found.

Referenced by Line2< T >::Collinear(), and Triangle< T >::Intersects().

Intersect() [2/2]

bool Intersect ( const Line2< T > &  _line, math::Vector2< T > &  _pt, double  _epsilon = 1e-6  ) const

inline

Check if this line intersects the given line segment. The point of intersection is returned in the _result parameter.

Parameters

[in]	_line	The line to check for intersection.
[out]	_pt	The point of intersection. This value is only valid if the return value is true.
[in]	_epsilon	The error bounds within which the intersection check will return true.

Returns

True if an intersection was found.

References Line2< T >::CrossProduct(), gz::math::equal(), std::max(), std::min(), Line2< T >::Within(), Vector2< T >::X(), and Vector2< T >::Y().

Length()

T Length ( ) const

inline

Get the length of the line.

Returns

The length of the line.

OnSegment()

bool OnSegment ( const math::Vector2< T > &  _pt, double  _epsilon = 1e-6  ) const

inline

Return whether the given point is on this line segment.

Parameters

[in]	_pt	Point to check.
[in]	_epsilon	The error bounds within which the OnSegment check will return true.

Returns

True if the point is on the segement.

References Line2< T >::Collinear(), and Line2< T >::Within().

operator!=()

bool operator!= ( const Line2< T > &  _line ) const

inline

Inequality operator.

Parameters

[in]

_line

Line to compare for inequality.

Returns

True if the given line is not to this line

operator==()

bool operator== ( const Line2< T > &  _line ) const

inline

Equality operator.

Parameters

[in]

_line

Line to compare for equality.

Returns

True if the given line is equal to this line

operator[]()

math::Vector2<T> operator[] ( size_t  _index ) const

inline

Get the start or end point.

Parameters

[in]

_index

0 = start point, 1 = end point. The _index is clamped to the range [0, 1]

References gz::math::clamp(), gz::math::GZ_ONE_SIZE_T, and gz::math::GZ_ZERO_SIZE_T.

Parallel()

bool Parallel ( const math::Line2< T > &  _line, double  _epsilon = 1e-6  ) const

inline

Check if the given line is parallel with this line.

Parameters

[in]	_line	The line to check.
[in]	_epsilon	The error bounds within which the parallel check will return true.

Returns

Return true if the line is parallel with this line, false otherwise. Return true if either line is a point (line with zero length).

References Line2< T >::CrossProduct(), and gz::math::equal().

Referenced by Line2< T >::Collinear().

Set() [1/2]

void Set ( const math::Vector2< T > &  _ptA, const math::Vector2< T > &  _ptB  )

inline

Set the start and end point of the line segment.

Parameters

[in]	_ptA	Start point of the line segment
[in]	_ptB	End point of the line segment

Referenced by Line2< T >::Line2().

Set() [2/2]

void Set ( double  _x1, double  _y1, double  _x2, double  _y2  )

inline

Set the start and end point of the line segment.

Parameters

[in]	_x1	X coordinate of the start point.
[in]	_y1	Y coordinate of the start point.
[in]	_x2	X coordinate of the end point.
[in]	_y2	Y coordinate of the end point.

Slope()

double Slope ( ) const

inline

Get the slope of the line.

Returns

The slope of the line, NAN_D if the line is vertical.

References gz::math::equal(), and gz::math::NAN_D.

Within()

bool Within ( const math::Vector2< T > &  _pt, double  _epsilon = 1e-6  ) const

inline

Check if the given point is between the start and end points of the line segment. This does not imply that the point is on the segment.

Parameters

[in]	_pt	Point to check.
[in]	_epsilon	The error bounds within which the within check will return true.

Returns

True if the point is on the segement.

References std::max(), std::min(), Vector2< T >::X(), and Vector2< T >::Y().

Referenced by Line2< T >::Intersect(), and Line2< T >::OnSegment().

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

• gz/math/Line2.hh