two-dimensional point

Collaboration diagram for two-dimensional point:

Data Structures
struct	a_point2
	instance structure for two-dimensional point More...

Macros
#define	A_POINT2_C(x, y)
#define	a_point2_c(x)
#define	a_point2_(_, x)

Typedefs
typedef struct a_point2	a_point2

Functions
void	a_vector2_set (a_vector2 *ctx, a_point2 const *p, a_point2 const *q)
	set a 2D vector as the difference from point p to point q.
void	a_point2_val (a_point2 const *ctx, a_real *x, a_real *y)
	get the cartesian coordinates of a 2D point.
void	a_point2_set_val (a_point2 *ctx, a_real x, a_real y)
	set the cartesian coordinates of a 2D point.
void	a_point2_pol (a_point2 const *ctx, a_real *rho, a_real *theta)
	get the polar coordinates of a 2D point.
void	a_point2_set_pol (a_point2 *ctx, a_real rho, a_real theta)
	set the polar coordinates of a 2D point.
void	a_point2_add (a_point2 const *lhs, a_vector2 const *rhs, a_point2 *res)
	add a 2D vector to a 2D point.
void	a_point2_sub (a_point2 const *lhs, a_vector2 const *rhs, a_point2 *res)
	subtract a 2D vector from a 2D point.
void	a_point2_mul (a_point2 const *lhs, a_real rhs, a_point2 *res)
	multiplie a 2D point by a scalar.
void	a_point2_div (a_point2 const *lhs, a_real rhs, a_point2 *res)
	divide a 2D point by a scalar.
void	a_point2_pos (a_point2 const *ctx, a_vector2 *res)
	convert it into a vector from the origin to the point.
void	a_point2_neg (a_point2 const *ctx, a_vector2 *res)
	convert it into a vector from the point to the origin.
a_real	a_point2_dist (a_point2 const *lhs, a_point2 const *rhs)
	compute the distance between two 2D points.
a_real	a_point2_dist2 (a_point2 const *lhs, a_point2 const *rhs)
	compute the squared distance between two 2D points.
a_real	a_point2_mindist (a_point2 const *ctx, a_point2 const *i_p, a_size i_n, a_point2 *o_p, a_size *o_i)
	compute the minimum distance from a reference point to a point set.
a_real	a_point2_maxdist (a_point2 const *ctx, a_point2 const *i_p, a_size i_n, a_point2 *o_p, a_size *o_i)
	compute the maximum distance from a reference point to a point set.
int	a_point2_cmpx (a_point2 const *lhs, a_point2 const *rhs)
	compare two 2D points primarily by X-coordinate, then by Y-coordinate.
int	a_point2_cmpy (a_point2 const *lhs, a_point2 const *rhs)
	compare two 2D points primarily by Y-coordinate, then by X-coordinate.
void	a_vector2::set (a_point2 const &p, a_point2 const &q)
	set a 2D vector as the difference from point p to point q.

Detailed Description

Macro Definition Documentation

a_point2_

#define a_point2_	(		_,
			x )

Value:

a_cast_s(a_point2 _, x)

A_POINT2_C

#define A_POINT2_C	(		x,
			y )

Value:

{a_real_c(x), a_real_c(y)}

constructs a two-dimensional point from cartesian coordinate

a_point2_c

#define a_point2_c

(

x

)

Value:

a_cast_s(a_point2, x)

static cast to two-dimensional point

Function Documentation

a_point2_cmpx()

int a_point2_cmpx	(	a_point2 const *	lhs,
		a_point2 const *	rhs )

compare two 2D points primarily by X-coordinate, then by Y-coordinate.

Parameters

[in]	lhs	is left-hand side 2D point
[in]	rhs	is right-hand side 2D point

Returns

relationship between 2D points

Return values

>0	if lhs is greater than rhs
<0	if lhs is less than rhs
0	if lhs is equal to rhs

a_point2_cmpy()

int a_point2_cmpy	(	a_point2 const *	lhs,
		a_point2 const *	rhs )

compare two 2D points primarily by Y-coordinate, then by X-coordinate.

Parameters

[in]	lhs	is left-hand side 2D point
[in]	rhs	is right-hand side 2D point

Returns

relationship between 2D points

Return values

>0	if lhs is greater than rhs
<0	if lhs is less than rhs
0	if lhs is equal to rhs

a_point2_dist()

a_real a_point2_dist	(	a_point2 const *	lhs,
		a_point2 const *	rhs )

compute the distance between two 2D points.

In two-dimensional space, let point \(p\) have coordinates \((p_x,p_y)\) and let point \(q\) have coordinates \((q_x,q_y)\). Then the distance between \(p\) and \(q\) is given by:

\[ d(p,q)=\sqrt{(p_x-q_x)^2+(p_y-q_y)^2} \]

Parameters

[in]	lhs	is left-hand side 2D point
[in]	rhs	is right-hand side 2D point

Returns

the distance between two 2D points

a_point2_dist2()

a_real a_point2_dist2	(	a_point2 const *	lhs,
		a_point2 const *	rhs )

compute the squared distance between two 2D points.

In two-dimensional space, let point \(p\) have coordinates \((p_x,p_y)\) and let point \(q\) have coordinates \((q_x,q_y)\). Then the squared distance between \(p\) and \(q\) is given by:

\[ d(p,q)^2=(p_x-q_x)^2+(p_y-q_y)^2 \]

Parameters

[in]	lhs	is left-hand side 2D point
[in]	rhs	is right-hand side 2D point

Returns

the squared distance between two 2D points

a_point2_maxdist()

a_real a_point2_maxdist	(	a_point2 const *	ctx,
		a_point2 const *	i_p,
		a_size	i_n,
		a_point2 *	o_p,
		a_size *	o_i )

compute the maximum distance from a reference point to a point set.

Parameters

[in]	ctx	points to the reference point
[in]	i_p	points to the points in memory
[in]	i_n	number of the points in memory
[out]	o_p	stores the farthest point; may be NULL
[out]	o_i	stores the index of the farthest point; may be NULL

Returns

the maximum distance from a reference point to a point set

Return values

-inf

failure

a_point2_mindist()

a_real a_point2_mindist	(	a_point2 const *	ctx,
		a_point2 const *	i_p,
		a_size	i_n,
		a_point2 *	o_p,
		a_size *	o_i )

compute the minimum distance from a reference point to a point set.

Parameters

[in]	ctx	points to the reference point
[in]	i_p	points to the points in memory
[in]	i_n	number of the points in memory
[out]	o_p	stores the nearest point; may be NULL
[out]	o_i	stores the index of the nearest point; may be NULL

Returns

the minimum distance from a reference point to a point set

Return values

+inf

failure

set()

void a_vector2::set ( a_point2 const & p, a_point2 const & q )

inline

set a 2D vector as the difference from point p to point q.

See also

a_vector2_set