# point Specification Sheet

Portable Object Compiler (c) 1997. All Rights Reserved.

# Point

Inherits from: Object

## Class Description

Point instances are implemented as pairs of two C integers. This is partly because of compatibility with the corresponding ICpak101 class, and partly because it (as opposed to some floating point arithmetic) gives portable results for equality testing.

## Method types

### Creation

- new
- x:y:

### Instance Variables

- x:y:
- x:
- y:
- x
- y

### Comparing

- hash
- isEqual:
- isBelow:
- isAbove:
- isLeft:
- isRight:

### Point Arithmetic

- moveBy:
- moveBy::
- moveTo:
- plus:

### Printing

- printOn:
- fileOutOn:
- fileInFrom:

## Methods

### new

> +new

Returns the point (0,0).

### x:y:

> +x:(int)x y:(int)y

Returns the point (x,y).

### x:y:

> -x:(int)x y:(int)y

Resets the coordinates of an existing point to (x,y).

### x:

> -x:(int)x

Resets the xLoc coordinate. Returns the receiver.

### y:

> -y:(int)y

Resets the yLoc coordinate. Returns the receiver.

### x

> - (int)x

Returns xLoc as int value.

### y

> - (int)y

Returns yLoc as int value.

### hash

> - (unsigned)hash

Returns a hash value based on the values of xLoc and yLoc.

### isEqual:

> - (BOOL)isEqual:aPoint

Returns YES if both arguments are instances of Point (or of a subclass of Point) and if they have the same coordinates.

### isBelow:

> - (BOOL)isBelow:aPoint

Returns YES if the receiver's y coordinate is greater than the y coordinate of aPoint.

### isAbove:

> - (BOOL)isAbove:aPoint

Returns YES if the receiver's y coordinate is less than the y coordinate of aPoint.

### isLeft:

> - (BOOL)isLeft:aPoint

Returns YES if the receiver's x coordinate is less than the x coordinate of aPoint.

### isRight:

> - (BOOL)isRight:aPoint

Returns YES if the receiver's x coordinate is greater than the x coordinate of aPoint.

### moveBy:

> -moveBy:aPoint

Adds coordinates of aPoint to the receiver. Unlike plus:, this method does not return a new object.

### moveBy::

> -moveBy:(int)x:(int)y

Adds x and y coordinates of aPoint to the receiver. Unlike plus:, this method does not return a new object.

### moveTo:

> -moveTo:aPoint

Copies the coordinates of aPoint into the receiver. Typically used for translation.

### plus:

> -plus:aPoint

This method is like moveBy: but it returns a new point instance.

### printOn:

> -printOn:(IOD)aFile

Prints x and y coordinates inside parenthesis.

### fileOutOn:

> -fileOutOn:aFiler

Writes the point on aFiler. Returns the receiver.

### fileInFrom:

> -fileInFrom:aFiler

Reads the point from aFiler. Returns the receiver.