math2d
[math]

2D Mathematics functions More...

Classes
struct	__vec2f
	2D point More...
struct	GF_Rect
	rectangle 2D More...
struct	GF_IRect
	pixel-aligned rectangle More...
struct	GF_Matrix2D
	2D matrix More...
Defines
#define	gf_mx2d_init(_obj)
	matrix initialization
#define	gf_mx2d_copy(_obj, from)
	matrix copy
#define	gf_mx2d_is_identity(_obj)
	matrix identity testing
Typedefs
typedef struct __vec2f	GF_Point2D
	2D point
Functions
Fixed	gf_v2d_len (GF_Point2D *vec)
	get 2D vector length
Fixed	gf_v2d_distance (GF_Point2D a, GF_Point2D b)
	get distance between 2 points
GF_Point2D	gf_v2d_from_polar (Fixed length, Fixed angle)
	2D vector from polar coordinates
void	gf_rect_union (GF_Rect rc1, GF_Rect rc2)
	rectangle union
GF_Rect	gf_rect_center (Fixed w, Fixed h)
	centers a rectangle
Bool	gf_rect_overlaps (GF_Rect rc1, GF_Rect rc2)
	rectangle overlap test
Bool	gf_rect_equal (GF_Rect rc1, GF_Rect rc2)
	rectangle identity test
GF_IRect	gf_rect_pixelize (GF_Rect *r)
	gets the pixelized version of a rectangle
void	gf_mx2d_add_matrix (GF_Matrix2D _this, GF_Matrix2D from)
	2D matrix multiplication
void	gf_mx2d_pre_multiply (GF_Matrix2D _this, GF_Matrix2D from)
	2D matrix pre-multiplication
void	gf_mx2d_add_translation (GF_Matrix2D *_this, Fixed cx, Fixed cy)
	matrix translating
void	gf_mx2d_add_rotation (GF_Matrix2D *_this, Fixed cx, Fixed cy, Fixed angle)
	matrix rotating
void	gf_mx2d_add_scale (GF_Matrix2D *_this, Fixed scale_x, Fixed scale_y)
	matrix scaling
void	gf_mx2d_add_scale_at (GF_Matrix2D *_this, Fixed scale_x, Fixed scale_y, Fixed cx, Fixed cy, Fixed angle)
	matrix uncentered scaling
void	gf_mx2d_add_skew (GF_Matrix2D *_this, Fixed skew_x, Fixed skew_y)
	matrix skewing
void	gf_mx2d_add_skew_x (GF_Matrix2D *_this, Fixed angle)
	matrix horizontal skewing
void	gf_mx2d_add_skew_y (GF_Matrix2D *_this, Fixed angle)
	matrix vertical skewing
void	gf_mx2d_inverse (GF_Matrix2D *_this)
	matrix inversing
void	gf_mx2d_apply_coords (GF_Matrix2D _this, Fixed x, Fixed *y)
	matrix coordinate transformation
void	gf_mx2d_apply_point (GF_Matrix2D _this, GF_Point2D pt)
	matrix point transformation
void	gf_mx2d_apply_rect (GF_Matrix2D _this, GF_Rect rc)
	matrix rectangle transformation
Bool	gf_mx2d_decompose (GF_Matrix2D _this, GF_Point2D scale, Fixed rotate, GF_Point2D translate)
	matrix decomposition

Detailed Description

This section documents mathematic tools for 2D geometry and color matrices operations

Define Documentation

#define gf_mx2d_init ( _obj )

Inits the matrix to the identity matrix

#define gf_mx2d_copy	(	_obj,
		from		)

Copies the matrix _from to the matrix _obj

#define gf_mx2d_is_identity ( _obj )

This macro evaluates to 1 if the matrix _obj is the identity matrix, 0 otherwise

Typedef Documentation

typedef struct __vec2f GF_Point2D

The 2D point object is used in all the GPAC framework for both point and vector representation.

Function Documentation

Fixed gf_v2d_len ( GF_Point2D * vec )

Gets the length of a 2D vector

Returns:: length of the vector

Fixed gf_v2d_distance	(	GF_Point2D *	a,
		GF_Point2D *	b
	)

Gets the distance between the 2 points

Returns:: distance

GF_Point2D gf_v2d_from_polar	(	Fixed	length,
		Fixed	angle
	)

Constructs a 2D vector from its polar coordinates

Parameters:

	length	the length of the vector
	angle	the angle of the vector in radians

Returns:: the 2D vector

void gf_rect_union	(	GF_Rect *	rc1,
		GF_Rect *	rc2
	)

Gets the union of two rectangles.

Parameters:

	rc1	first rectangle of the union. Upon return, this rectangle will contain the result of the union
	rc2	second rectangle of the union

GF_Rect gf_rect_center	(	Fixed	w,
		Fixed	h
	)

Builds a rectangle centered on the origin

Parameters:

	w	width of the rectangle
	h	height of the rectangle

Returns:: centered rectangle object

Bool gf_rect_overlaps	(	GF_Rect	rc1,
		GF_Rect	rc2
	)

Tests if two rectangles overlap.

Parameters:

	rc1	first rectangle to test
	rc2	second rectangle to test

Returns:: 1 if rectangles overlap, 0 otherwise

Bool gf_rect_equal	(	GF_Rect	rc1,
		GF_Rect	rc2
	)

Tests if two rectangles are identical.

Parameters:

	rc1	first rectangle to test
	rc2	second rectangle to test

Returns:: 1 if rectangles are identical, 0 otherwise

GF_IRect gf_rect_pixelize ( GF_Rect * r )

Returns the smallest pixel-aligned rectangle completely containing a rectangle

Parameters:

r

the rectangle to transform

Returns:: the pixel-aligned transformed rectangle

void gf_mx2d_add_matrix	(	GF_Matrix2D *	_this,
		GF_Matrix2D *	from
	)

Multiplies two 2D matrices from*_this

Parameters:

	_this	matrix being transformed. Once the function is called, _this contains the result matrix
	from	transformation matrix to add

void gf_mx2d_pre_multiply	(	GF_Matrix2D *	_this,
		GF_Matrix2D *	from
	)

Multiplies two 2D matrices _this*from

Parameters:

	_this	matrix being transformed. Once the function is called, _this contains the result matrix
	from	transformation matrix to add

void gf_mx2d_add_translation	(	GF_Matrix2D *	_this,
		Fixed	cx,
		Fixed	cy
	)

Translates a 2D matrix

Parameters:

	_this	matrix being transformed. Once the function is called, _this contains the result matrix
	cx	horizontal translation
	cy	vertical translation

void gf_mx2d_add_rotation	(	GF_Matrix2D *	_this,
		Fixed	cx,
		Fixed	cy,
		Fixed	angle
	)

Rotates a 2D matrix

Parameters:

	_this	matrix being transformed. Once the function is called, _this contains the result matrix
	cx	horizontal rotation center coordinate
	cy	vertical rotation center coordinate
	angle	rotation angle in radians

void gf_mx2d_add_scale	(	GF_Matrix2D *	_this,
		Fixed	scale_x,
		Fixed	scale_y
	)

Scales a 2D matrix

Parameters:

	_this	matrix being transformed. Once the function is called, _this contains the result matrix
	scale_x	horizontal scaling factor
	scale_y	vertical scaling factor

void gf_mx2d_add_scale_at	(	GF_Matrix2D *	_this,
		Fixed	scale_x,
		Fixed	scale_y,
		Fixed	cx,
		Fixed	cy,
		Fixed	angle
	)

Scales a 2D matrix with a non-centered scale

Parameters:

	_this	matrix being transformed. Once the function is called, _this contains the result matrix
	scale_x	horizontal scaling factor
	scale_y	vertical scaling factor
	cx	horizontal scaling center coordinate
	cy	vertical scaling center coordinate
	angle	scale orienttion angle in radians

void gf_mx2d_add_skew	(	GF_Matrix2D *	_this,
		Fixed	skew_x,
		Fixed	skew_y
	)

Skews a 2D matrix

Parameters:

	_this	matrix being transformed. Once the function is called, _this contains the result matrix
	skew_x	horizontal skew factor
	skew_y	vertical skew factor

void gf_mx2d_add_skew_x	(	GF_Matrix2D *	_this,
		Fixed	angle
	)

Skews a 2D matrix horizontally by a given angle

Parameters:

	_this	matrix being transformed. Once the function is called, _this contains the result matrix
	angle	horizontal skew angle in radians

void gf_mx2d_add_skew_y	(	GF_Matrix2D *	_this,
		Fixed	angle
	)

Skews a 2D matrix vertically by a given angle

Parameters:

	_this	matrix being transformed. Once the function is called, _this contains the result matrix
	angle	vertical skew angle in radians

void gf_mx2d_inverse ( GF_Matrix2D * _this )

Inverses a 2D matrix

Parameters:

_this

matrix being transformed. Once the function is called, _this contains the result matrix

void gf_mx2d_apply_coords	(	GF_Matrix2D *	_this,
		Fixed *	x,
		Fixed *	y
	)

Applies a 2D matrix transformation to coordinates

Parameters:

	_this	transformation matrix
	x	pointer to horizontal coordinate. Once the function is called, x contains the transformed horizontal coordinate
	y	pointer to vertical coordinate. Once the function is called, y contains the transformed vertical coordinate

void gf_mx2d_apply_point	(	GF_Matrix2D *	_this,
		GF_Point2D *	pt
	)

Applies a 2D matrix transformation to a 2D point

Parameters:

	_this	transformation matrix
	pt	pointer to 2D point. Once the function is called, pt contains the transformed point

void gf_mx2d_apply_rect	(	GF_Matrix2D *	_this,
		GF_Rect *	rc
	)

Applies a 2D matrix transformation to a rectangle, giving the enclosing rectangle of the transformed one

Parameters:

	_this	transformation matrix
	rc	pointer to rectangle. Once the function is called, rc contains the transformed rectangle

Bool gf_mx2d_decompose	(	GF_Matrix2D *	_this,
		GF_Point2D *	scale,
		Fixed *	rotate,
		GF_Point2D *	translate
	)

Decomposes a 2D matrix M as M=Scale x Rotation x Translation if possible

Parameters:

	_this	transformation matrix
	scale	resulting scale part
	rotate	resulting rotation part
	translate	resulting translation part

Returns:: 0 if matrix cannot be decomposed, 1 otherwise

math2d [math]

Classes

Defines

Typedefs

Functions

Detailed Description

Define Documentation

Typedef Documentation

Function Documentation

math2d
[math]