BPoint

Derived from: none

Declared in: be/interface/Point.h

Library: libbe.so

Allocation: Constructor or on the stack, typically the latter.

Summary

BPoint objects represent points on a two-dimensional coordinate grid. The object's coordinates are stored as public x and y data members. The BPoint class declares a global object, B_ORIGIN, that represents (0,0).

For an overview of coordinate geometry for the BeOS, see  "The Coordinate Space" on page52.

Data Members

float x   
The coordinate value measured horizontally along the x-axis.

float y   
The coordinate value measured vertically along the y-axis.

Constructor

BPoint()

	inline BPoint(float x, float y) inline BPoint(const BPoint& point) inline BPoint(void)

Creates a new BPoint object that corresponds to the point (x, y), or that's copied from point. If no coordinate values are assigned, the BPoint's location is indeterminate.

See also: Set(), the assignment operator

Member Functions

ConstrainTo()

	void ConstrainTo(BRect rect)

Ensures that the BPoint lies within rect. If it's already contained in the rectangle, the BPoint is unchanged; otherwise, it's moved to the rect's nearest edge.

See also: BRect::Contains()

PrintToStream()

	void PrintToStream(void) const

Prints the BPoint's coordinates to standard output in the form:

   "BPoint(x, y)"

Set()

	inline void Set(float x, float y)

Sets the BPoint's x and y coordinates.

See also: the BPoint constructor

Operators

= (assignment)

	inline BPoint& operator =(const BPoint &from)

Copies from's coordinate data into the left-side object.

== (equality), != (inequality)

	bool operator ==(BPoint) const bool operator !=(BPoint) const

== returns true if the two objects' point exactly coincide.

!= returns true if the two objects' points don't coincide.

+ (addition), += (addition and assignment)

	BPoint operator +(const BPoint&) const BPoint& operator +=(const BPoint&)

+ creates and returns a new BPoint that adds the two operands together. The new object's x coordinate is the sum of the operands' x values; its y value is the sum of the operands' y values.

+= adds the operands together and stores the result in the left operand.

– (subtraction), –= (subtraction and assignment)

	BPoint operator –(const BPoint&) const BPoint& operator –=(const BPoint&)

- creates and returns a new BPoint that subtracts the right operand from the left. The new object's x coordinate is the difference between the operands' x values; its y value is the difference between the operands' y values.

-= performs the subtraction and stores the result in the left operand.

Global Objects

B_ORIGIN

BPoint object that represents (0,0).