Box2 Class Reference

#include <box2.h>

Inheritance diagram for Box2:

Public Member Functions
	Box2 ()
	Box2 (const IPoint2 &a, const IPoint2 &b)
bool	IsEmpty ()
void	SetEmpty ()
void	Rectify ()
void	Scale (float f)
void	Translate (IPoint2 t)
IPoint2	GetCenter () const
int	x () const
int	y () const
int	w () const
int	h () const
void	SetW (int w)
void	SetH (int h)
void	SetX (int x)
void	SetY (int y)
void	SetWH (int w, int h)
void	SetXY (int x, int y)
Box2 &	operator= (const RECT &r)
Box2 &	operator= (RECT &r)
Box2 &	operator+= (const Box2 &b)
Box2 &	operator+= (const IPoint2 &p)
bool	operator== (const Box2 &b) const
bool	operator!= (const Box2 &b) const
bool	Contains (const IPoint2 &p) const
bool	IntersectsLine (int x0, int y0, int x1, int y1) const

Detailed Description

See also

Class IPoint2.

Description:

This class describes a 2D rectangular region using integer coordinates. This class is sub-classed from RECT (from the Windows API). Box2 provides methods that return individual coordinates of the box, scale and translate it, retrieve its center, modify its size, expand it to include points or other boxes, and determine if points are inside the box. All methods are implemented by the system.

Constructor & Destructor Documentation

Box2() [1/2]

Box2

(

)

Remarks

Constructs a Box2 object. The box is initialized such that it is 'empty'. See IsEmpty() below.

Box2() [2/2]

Box2	(	const IPoint2 &	a,
		const IPoint2 &	b
	)

Remarks

Constructs a Box2 object from the specified corners.

Parameters:

const IPoint2 a

The upper left corner of the box.

const IPoint2 b

The lower right corner of the box.

Member Function Documentation

IsEmpty()

bool IsEmpty

(

)

Remarks

Determines whether the box has been 'Set Empty' (see below). When a box is created using the default constructor it is set to 'empty'.

Returns

true if the box is empty; false otherwise.

SetEmpty()

void SetEmpty

(

)

Remarks

Sets the box to 'empty'. This indicates the box has not had specific values set by the developer.

Rectify()

void Rectify

(

)

Remarks

Adjusts the coordinates of the box such that top<bottom and left<right.

Scale()

void Scale

(

float

f

)

Remarks

Scales the coordinates of the box about the center of the box.

Parameters:

float f

Specifies the scale factor.

Translate()

void Translate

(

IPoint2

t

)

Remarks

Translate the box by the distance specified.

Parameters:

IPoint2 t

The distance to translate the box.

GetCenter()

IPoint2 GetCenter ( ) const

inline

Remarks

Returns the center of the box (the midpoint between the box corners).

    {
        return IPoint2((left + right) / 2, (top + bottom) / 2);
    }

x()

int x ( ) const

inline

Remarks

Returns the minimum x coordinate of the box.

    {
        return ((left < right) ? left : right);
    }

y()

int y ( ) const

inline

Remarks

Returns the minimum y coordinate.

    {
        return ((top < bottom) ? top : bottom);
    }

w()

int w ( ) const

inline

Remarks

Returns the width of the box.

    {
        return abs(right - left) + 1;
    }

h()

int h ( ) const

inline

Remarks

Returns the height of the box.

    {
        return abs(bottom - top) + 1;
    }

SetW()

void SetW ( int  w )

inline

Remarks

Sets the box width to the width specified. The 'right' coordinate is adjusted such that:

right = left + w -1

Parameters:

int w

The new width for the box.

    {
        right = left + w - 1;
    }

SetH()

void SetH ( int  h )

inline

Remarks

Sets the height of the box to the height specified. The 'bottom' coordinate is adjusted such that:

bottom = top + h -1;

Parameters:

int h

The new height for the box.

    {
        bottom = top + h - 1;
    }

SetX()

void SetX ( int  x )

inline

Remarks

Sets the left coordinate of the box to x.

Parameters:

int x

The new value for the left coordinate.

    {
        left = x;
    }

SetY()

void SetY ( int  y )

inline

Remarks

Set the top coordinate to y.

Parameters:

int y

The new value for the top coordinate.

    {
        top = y;
    }

SetWH()

void SetWH ( int  w, int  h  )

inline

Remarks

Sets both the width and height of the box.

Parameters:

int w

The new width for the box.

int h

The new height of the box.

    {
        SetW(w);
        SetH(h);
    }

SetXY()

void SetXY ( int  x, int  y  )

inline

Remarks

Sets both the left and top coordinates of the box.

Parameters:

int x

The new left coordinate.

int y

The new top coordinate.

    {
        SetX(x);
        SetY(y);
    }

operator=() [1/2]

Box2 & operator=

(

const RECT &

r

)

Remarks

Assignment operators. Copies the specified source RECT into this Box2 object.

operator=() [2/2]

Box2 & operator=

(

RECT &

r

)

Remarks

Assignment operators. Copies the specified source RECT into this Box2 object.

operator+=() [1/2]

Box2 & operator+=

(

const Box2 &

b

)

Remarks

Expands this Box2 to completely include box b.

operator+=() [2/2]

Box2 & operator+=

(

const IPoint2 &

p

)

Remarks

Expands this Box2 to include point p.

operator==()

bool operator== ( const Box2 &  b ) const

inline

Remarks

Equality operator. Determines whether b is equal to this box. Returns true if the boxes are equal; false otherwise.

    {
        return (left == b.left && right == b.right && top == b.top && bottom == b.bottom);
    }

operator!=()

bool operator!= ( const Box2 &  b ) const

inline

Remarks

Inequality operator. Determines whether b is different from this box. Returns true if the boxes are different.

    {
        return !(operator==(b));
    }

Contains()

bool Contains

(

const IPoint2 &

p

)

const

Remarks

Determines if the point passed is contained within the box. Returns true if the point is inside the box; otherwise false.

IntersectsLine()

bool IntersectsLine	(	int	x0,
		int	y0,
		int	x1,
		int	y1
	)		const

Remarks

Intersection test between a line and a rectangle. Returns true if they intersect.

Parameters:

int x0

Line start x coordinate.

int y0

Line start y coordinate. int x1

Line end x coordinate.

int y1

Line end y coordinate.