Point--X-Y Coordinate Pair

#include <nihcl/Point.h>

Instances of class Point represent x-y coordinate pairs. By (Smalltalk-80) convention, Point(0,0) is the top left corner of the display, with x increasing to the right and y increasing to the bottom.

CONSTRUCTORS

Point(): Constructs an instance of class Point initialized to (0,0).
Point(short newx, short newy): Constructs an instance of class Point initialized to (newx,newy).

ACCESSING POINTS

short x() const
short y() const: Returns the x or y coordinate value of this Point.
short x(short newx)
short y(short newy): Sets the x or y coordinate value of this Point to newx or newy, respectively, and returns the new value.

SEARCHING

virtual unsigned hash() const: Returns a value suitable for use as a hash table probe.

RELATIONAL OPERATORS

bool operator==(const Point&) const
bool operator!=(const Point&) const: Returns YES if the left Point operand is equal to (or not equal to) the right Point operand.
bool operator<(const Point&) const
bool operator<=(const Point&) const
bool operator>(const Point&) const
bool operator>=(const Point&) const: Returns YES if the relation holds between both the x and y coordinates of the operands. For example, point (Ax,Ay) < point (Bx,By) if Ax < Bx and Ay < By.

ARITHMETIC OPERATORS

Point operator-() const

Returns a Point with x and y coordinate values opposite in sign from the x and y coordinate values of the operand Point. For example, -Point(1,2) is (-1,-2).

Point operator+(const Point&) const

Point operator-(const Point&) const

Returns a Point with x and y coordinate values that are the sum or difference of the x and y coordinate values of the operand Points. For example, Point(1,2) + Point(3,4) is (4,6).

friend Point operator*(const Point& p, int i)

friend Point operator*(int i, const Point& p)

Scales the x and y coordinates of Point p by the integer i. For example, 2 * Point(1,2) is (2,4).

int operator*(const Point&) const

Returns the sum of the products of the x and y coordinate values of the operand Points. For example, Point(1,2) * Point(3,4) is 1*3 + 2*4 = 11.

void operator+=(const Point&)

void operator-=(const Point&)

Replaces this Point by one that is the sum or difference of the x and y coordinates of this Point and those of the right operand Point. For example

Point p(1,2);
p += Point(3,4);
cout << p << endl;

prints (4,6).

void operator*=(int s)

Replaces this Point by one with the x and y coordinates each multiplied by s. For example:

Point p(1,2);
p *= 10;
cout << p << endl;

prints (10,20).

COMPARING POINTS

Point max(const Point& p) const
Point min(const Point& p) const: Returns a Point whose x coordinate is the larger (smaller) of this Point's x coordinate and that of p, and whose y coordinate is the larger (smaller) of this Point's y coordinate and that of p.
virtual int compare(const Object& ob) const: Compares this Point with the argument object ob, which must also be an instance of class Point. Returns a negative result if this Point is less than ob, zero if this Point equals ob, and a positive result if this Point is greater than ob. One point is considered greater than another if its y coordinate is greater, or if its y coordinate is equal and its x coordinate is greater.

TESTING POINTS

bool isBelow(const Point& p) const { return yc > p.yc; }
bool isAbove(const Point& p) const { return yc < p.yc; }: Returns YES if the y coordinate of this Point is greater than (or less than, respectively) the y coordinate of Point p.
bool isRight(const Point& p) const { return xc > p.xc; }
bool isLeft(const Point& p) const { return xc < p.xc; }: Returns YES if the x coordinate of this Point is greater than (or less than, respectively) the x coordinate of Point p.
virtual bool isEqual(const Object& ob) const: Returns YES if ob is of species Point and equals this Point.

CONVERTING POINTS

double dist(const Point& p) const: Returns the distance between this Point and the Point p.
Point transpose() const: Returns a Point whose x coordinate is equal to the y coordinate of this Point and whose y coordinate is equal to the x coordinate of this Point.