Bezier Curve

Data Structures
struct	_Eina_Bezier

Typedefs
typedef struct _Eina_Bezier	Eina_Bezier
	Floating point cubic bezier curve.

Functions
EINA_API void	eina_bezier_values_set (Eina_Bezier *b, double start_x, double start_y, double ctrl_start_x, double ctrl_start_y, double ctrl_end_x, double ctrl_end_y, double end_x, double end_y)
	Sets the values of the points of the given floating point cubic bezier curve. More...
EINA_API void	eina_bezier_values_get (const Eina_Bezier *b, double *start_x, double *start_y, double *ctrl_start_x, double *ctrl_start_y, double *ctrl_end_x, double *ctrl_end_y, double *end_x, double *end_y)
	Gets the values of the points of the given floating point cubic bezier curve. More...
EINA_API double	eina_bezier_length_get (const Eina_Bezier *b)
	Calculates the approximate length of the given floating point cubic bezier curve. More...
EINA_API double	eina_bezier_t_at (const Eina_Bezier *b, double len)
	Returns the relative position on a bezier at a given length. More...
EINA_API void	eina_bezier_point_at (const Eina_Bezier *b, double t, double *px, double *py)
	Gets the point on the bezier curve at position t. More...
EINA_API double	eina_bezier_angle_at (const Eina_Bezier *b, double t)
	Determines the slope of the bezier at a given position. More...
EINA_API void	eina_bezier_split_at_length (const Eina_Bezier *b, double len, Eina_Bezier *left, Eina_Bezier *right)
	Splits the bezier at a given length. More...
EINA_API void	eina_bezier_bounds_get (const Eina_Bezier *b, double *x, double *y, double *w, double *h)
	Calculates the bounding box for the bezier. More...
EINA_API void	eina_bezier_on_interval (Eina_Bezier *b, double t0, double t1, Eina_Bezier *result)
	Finds the bezier between the given interval. More...

Detailed Description

Function Documentation

eina_bezier_values_set()

EINA_API void eina_bezier_values_set	(	Eina_Bezier *	b,
		double	start_x,
		double	start_y,
		double	ctrl_start_x,
		double	ctrl_start_y,
		double	ctrl_end_x,
		double	ctrl_end_y,
		double	end_x,
		double	end_y
	)

Sets the values of the points of the given floating point cubic bezier curve.

Parameters

[out]	b	The floating point bezier.
[in]	start_x	The x coordinate of the start point.
[in]	start_y	The y coordinate of the start point.
[in]	ctrl_start_x	The x coordinate of the 1st control point.
[in]	ctrl_start_y	The y coordinate of the 1st control point.
[in]	ctrl_end_x	The X coordinate of the 2nd control point.
[in]	ctrl_end_y	The Y coordinate of the 2nd control point.
[in]	end_x	The X coordinate of the end point.
[in]	end_y	The Y coordinate of the end point.

b. No check is done on b.

Since

1.16

eina_bezier_values_get()

EINA_API void eina_bezier_values_get	(	const Eina_Bezier *	b,
		double *	start_x,
		double *	start_y,
		double *	ctrl_start_x,
		double *	ctrl_start_y,
		double *	ctrl_end_x,
		double *	ctrl_end_y,
		double *	end_x,
		double *	end_y
	)

Gets the values of the points of the given floating point cubic bezier curve.

Parameters

[in]	b	The floating point bezier.
[out]	start_x	x coordinate of start point.
[out]	start_y	y coordinate of start point.
[out]	ctrl_start_x	x coordinate of 1st control point.
[out]	ctrl_start_y	y coordinate of 1st control point.
[out]	ctrl_end_x	x coordinate of 2nd control point.
[out]	ctrl_end_y	y coordinate of 2nd control point.
[out]	end_x	x coordinate of end point.
[out]	end_y	y coordinate of end point.

b. No check is done on b.

Since

1.16

eina_bezier_length_get()

EINA_API double eina_bezier_length_get

(

const Eina_Bezier *

b

)

Calculates the approximate length of the given floating point cubic bezier curve.

Parameters

[in]

b

The floating point bezier.

Returns

The bezier's length.

The curve length is approximated using the Alpha max plus beta min algorithm, which is designed to give fast results with a maximum error of less than 7% compared with the correct value.

No check is done on b.

Since

1.16

Referenced by eina_bezier_t_at().

eina_bezier_t_at()

EINA_API double eina_bezier_t_at	(	const Eina_Bezier *	b,
		double	len
	)

Returns the relative position on a bezier at a given length.

Parameters

[in]	b	The floating point bezier.
[in]	len	The length along the bezier curve.

Returns

The relative position from 0.0 to 1.0.

Calculates the proportional location on b as a number from 0.0 to 1.0 that corresponds to a distance len along it. Returns 1.0 if len is equal or greater than the bezier's length.

No check is done on b.

Since

1.16

References eina_bezier_length_get(), and EINA_DBL_EQ.

Referenced by eina_bezier_split_at_length().

eina_bezier_point_at()

EINA_API void eina_bezier_point_at	(	const Eina_Bezier *	b,
		double	t,
		double *	px,
		double *	py
	)

Gets the point on the bezier curve at position t.

Parameters

[in]	b	The floating point bezier.
[in]	t	The floating point position between 0.0 and 1.0.
[out]	px	The corresponding point's X coordinate.
[out]	py	The corresponding point's Y coordinate.

No check is done on b.

Since

1.16

References _Eina_Bezier::x, and _Eina_Bezier::y.

eina_bezier_angle_at()

EINA_API double eina_bezier_angle_at	(	const Eina_Bezier *	b,
		double	t
	)

Determines the slope of the bezier at a given position.

Parameters

[in]	b	The floating point bezier.
[out]	t	The position along the bezier between 0.0 and 1.0.

No check is done on b.

Since

1.16

eina_bezier_split_at_length()

EINA_API void eina_bezier_split_at_length	(	const Eina_Bezier *	b,
		double	len,
		Eina_Bezier *	left,
		Eina_Bezier *	right
	)

Splits the bezier at a given length.

Parameters

[in]	b	The floating point bezier.
[in]	len	The length along the bezier to make the split.
[out]	left	The resultant split's left portion of the bezier.
[out]	right	The resultant split's right portion of the bezier.

No check is done on b.

Since

1.16

References eina_bezier_t_at().

eina_bezier_bounds_get()

EINA_API void eina_bezier_bounds_get	(	const Eina_Bezier *	b,
		double *	x,
		double *	y,
		double *	w,
		double *	h
	)

Calculates the bounding box for the bezier.

Parameters

[in]	b	The floating point bezier.
[out]	x	The X coordinate of the bounding box.
[out]	y	The Y coordinate of the bounding box.
[out]	w	The width of the bounding box.
[out]	h	The height of the bounding box.

No check is done on b.

Since

1.17

eina_bezier_on_interval()

EINA_API void eina_bezier_on_interval	(	Eina_Bezier *	b,
		double	t0,
		double	t1,
		Eina_Bezier *	result
	)

Finds the bezier between the given interval.

Parameters

[in]	b	The floating point bezier.
[in]	t0	The start of the interval.
[in]	t1	The end of the interval.
[out]	result	The resulting bezier.

No check is done on b.

Since

1.17

References EINA_DBL_EQ.