"

 COPYRIGHT (c) 1989 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

ArithmeticValue subclass:#Point

       instanceVariableNames:'x y'

       classVariableNames:'PointZero PointOne'

       poolDictionaries:''

       category:'Graphics-Primitives'

!

Point comment:'

COPYRIGHT (c) 1989 by Claus Gittinger

	      All Rights Reserved

'!

!Point class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1989 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

version

"

"

!

documentation

"

    I represent a point in 2D space. Or I can be used to represent

    an extent (of a rectangle, for example), in which case my x-coordinate 

    represents the width, and y-coordinate the height of something.

    The x and y coordinate are usually numbers.

    Instance variables:

	x              <Number>        the x-coordinate of myself

	y              <Number>        the y-coordinate of myself

"

! !

!Point class methodsFor:'initialization'!

initialize

    PointZero := 0 @ 0.

    PointOne  := 1 @ 1

! !

!Point class methodsFor:'constants'!

zero

    "return the neutral element for addition"

    ^ PointZero

!

unity

    "return the neutral element for multiplication"

    ^ PointOne

! !

!Point class methodsFor:'queries'!

isBuiltInClass

    "this class is known by the run-time-system"

    ^ self == Point

! !

!Point class methodsFor:'instance creation'!

x:newX y:newY

    "create and return a new point with coordinates newX and newY"

%{  /* NOCONTEXT */

    /*

     * claus: I am no longer certain, if this primitive is worth the effort

     */

    if (self == Point) {

	if (_CanDoQuickNew(sizeof(struct point))) {

	    OBJ newPoint;

	    _qCheckedAlignedNew(newPoint, sizeof(struct point));

	    _InstPtr(newPoint)->o_class = Point;

	    _PointInstPtr(newPoint)->p_x = newX;

	    _PointInstPtr(newPoint)->p_y = newY;

	    __STORE(newPoint, newX);

	    __STORE(newPoint, newY);

	    RETURN ( newPoint );

	}

    }

%}

.

    ^ (self basicNew) x:newX y:newY

!

readFrom:aStream onError:exceptionBlock

    "return the next Point from the (character-)stream aStream;

     skipping all whitespace first; return the value of exceptionBlock,

     if no point can be read."

    |newX newY|

    newX := Number readFrom:aStream onError:[^exceptionBlock value].

    newX isNil ifTrue:[^ nil].

    (aStream skipSeparators ~~ $@) ifTrue:[^nil].

    aStream next.

    newY := Number readFrom:aStream onError:[^exceptionBlock value].

    newY isNil ifTrue:[^ nil].

    ^ (self basicNew) x:newX y:newY

    "

     Point readFrom:('1.234 @ 5.678' readStream)

     Point readFrom:('fooBar' readStream) onError:[0@0]

    "  

! !

!Point methodsFor:'accessing'!

x

    "return the x coordinate"

    ^ x

!

y

    "return the y coordinate"

    ^ y

!

x:newX

    "set the x coordinate to be the argument, aNumber.

     This is destructive (modifies the receiver, not a copy) and 

     should only be used if you know, that you are the exclusive owner 

     of the receiver."

    x := newX

!

y:newY

    "set the y coordinate to be the argument, aNumber.

     This is destructive (modifies the receiver, not a copy) and 

     should only be used if you know, that you are the exclusive owner 

     of the receiver."

    y := newY

!

x:newX y:newY

    "set both the x and y coordinates.

     This is destructive (modifies the receiver, not a copy) and 

     should only be used if you know, that you are the exclusive owner 

     of the receiver."

    x := newX.

    y := newY

! !

!Point methodsFor:'comparing'!

hash

    "return a number for hashing"

    x = y ifTrue:[^ x hash].

"

 used to be:

    ^ (x hash) bitXor:(y hash)

 the following handles 1@x vs. x@1 better:

"

    ^ (x hash) bitXor:(y hash bitShift:12)

!

< aPoint

    "return true if the receiver is above and to the left

     of the argument, aPoint"

    |p|

    p := aPoint asPoint.

    x >= (p x) ifTrue:[^ false].

    y >= (p y) ifTrue:[^ false].

    ^ true

!

> aPoint

    "return true if  the receiver is below and to the right

     of the argument, aPoint"

    |p|

    p := aPoint asPoint.

    x <= (p x) ifTrue:[^ false].

    y <= (p y) ifTrue:[^ false].

    ^ true

!

= aPoint

    "return true if the receiver represents the same point as

     the argument, aPoint"

    |p|

    (aPoint isMemberOf:Point) ifTrue:[     "this is a hint to STC"

	x ~= (aPoint x) ifTrue:[^ false].

	y ~= (aPoint y) ifTrue:[^ false].

	^ true

    ].

    aPoint respondsToArithmetic ifFalse:[ ^ false].

    p := aPoint asPoint.

    x ~= (p x) ifTrue:[^ false].

    y ~= (p y) ifTrue:[^ false].

    ^ true

!

max:aPoint

    "return the lower right corner of the rectangle uniquely defined by

     the receiver and the argument, aPoint"

    |p maxX maxY|

    p := aPoint asPoint.

    maxX := x max:(p x).

    maxY := y max:(p y).

    ^ maxX @ maxY

!

min:aPoint

    "return the upper left corner of the rectangle uniquely defined by

     the receiver and the argument, aPoint"

    |p minX minY|

    p := aPoint asPoint.

    minX := x min:(p x).

    minY := y min:(p y).

    ^ minX @ minY

! !

!Point methodsFor:'coercing & converting'!

generality

    "return the generality value - see ArithmeticValue>>retry:coercing:"

    ^ 120

!

coerce:anObject

    "return aNumber converted into receivers type"

    ^ anObject asPoint

!

asPoint

    "return the receiver as Point - this is the receiver"

    ^ self

!

asRectangle

    "return a zero-width rectangle consisting of origin 

     and corner being the receiver"

    ^ self corner:self

! !

!Point methodsFor:'creating rectangles'!

corner:aPoint

    "return a rectangle whose origin is self and corner is aPoint"

    ^ Rectangle origin:self corner:aPoint

!

extent:aPoint

    "return a rectangle whose origin is self and extent is aPoint"

    ^ Rectangle origin:self extent:aPoint

! !

!Point methodsFor:'transformations'!

+ scale 

    "Return a new Point that is the sum of the 

     receiver and scale (which is a Point or Number)."

    |scalePoint|

    "speedup for common cases ..."

    (scale isMemberOf:Point) ifTrue:[     

	^ (x + scale x) @ (y + scale y)

    ].

    scale isNumber ifTrue:[

	^ (x + scale) @ (y + scale)

    ].

    "this is the general (& clean) code ..."

    scalePoint := scale asPoint.

    ^ (x + scalePoint x) @ (y + scalePoint y)

!

- scale 

    "Return a new Point that is the difference of the 

     receiver and scale (which is a Point or Number)."

    |scalePoint|

    "speedup for common cases ..."

    (scale isMemberOf:Point) ifTrue:[     

	^ (x - scale x) @ (y - scale y)

    ].

    scale isNumber ifTrue:[

	^ (x - scale) @ (y - scale)

    ].

    "this is the general (& clean) code ..."

    scalePoint := scale asPoint.

    ^ (x - scalePoint x) @ (y - scalePoint y)

!

* scale 

    "Return a new Point that is the product of the 

     receiver and scale (which is a Point or Number)."

    |scalePoint|

    "speedup for common cases ..."

    (scale isMemberOf:Point) ifTrue:[    

	^ (x * scale x) @ (y * scale y)

    ].

    scale isNumber ifTrue:[

	^ (x * scale) @ (y * scale)

    ].

    "this is the general (& clean) code ..."

    scalePoint := scale asPoint.

    ^ (x * scalePoint x) @ (y * scalePoint y)

!

/ scale 

    "Return a new Point that is the integer quotient of the 

     receiver and scale (which is a Point or Number)."

    |scalePoint|

    "speedup for common cases ..."

    (scale isMemberOf:Point) ifTrue:[    

	^ (x / scale x) @ (y / scale y)

    ].

    scale isNumber ifTrue:[

	^ (x / scale) @ (y / scale)

    ].

    "this is the general (& clean) code ..."

    scalePoint := scale asPoint.

    ^ (x / scalePoint x) @ (y / scalePoint y)

!

// scale 

    "Return a new Point that is the quotient of the 

     receiver and scale (which is a Point or Number)."

    |scalePoint|

    scalePoint := scale asPoint.

    ^ (x // scalePoint x) @ (y // scalePoint y)

!

reciprocal

    "return a new point where the coordinates are

     the reciproce of mine"

    ^ (1 / x) @ (1 / y)

!

negated

    "return a new point with my coordinates negated 

     i.e. the receiver mirrored at the origin"

    ^ (x negated) @ (y negated)

! 

scaledBy:aScale

    "return a new Point that is the product of the 

     receiver and scale (which is a Point or Number)."

    ^ self * aScale

!

translatedBy:anOffset

    "return a new Point that is the sum of the 

     receiver and scale (which is a Point or Number)."

    ^ self + anOffset

! !

!Point methodsFor:'destructive transformations'!

scaleBy:aScale

    "scale the receiver, by replacing coordinates by the product

     of the receivers coordinates and the scale (a Point or Number).

     This is destructive (modifies the receiver, not a copy) and 

     should only be used if you know, that you are the exclusive owner 

     of the receiver."

    |scalePoint|

    (aScale isMemberOf:Point) ifTrue:[  "type hint to stc"  

	x := x * aScale x.

	y := y * aScale y.

	^ self

    ].

    aScale isNumber ifTrue:[

	x := x * aScale.

	y := y * aScale.

	^ self

    ].

    "this is the general (& clean) code ..."

    scalePoint := aScale asPoint.

    x := x * scalePoint x.

    y := y * scalePoint y

!

translateBy:anOffset

    "translate the receiver, by replacing coordinates by the sum

     of the receivers coordinated and the scale (a Point or Number).

     This is destructive (modifies the receiver, not a copy) and 

     should only be used if you know, that you are the exclusive owner 

     of the receiver."

    |offsetPoint|

    (anOffset isMemberOf:Point) ifTrue:[ "type hint to stc"   

	x := x + anOffset x.

	y := y + anOffset y.

	^ self

    ].

    anOffset isNumber ifTrue:[

	x := x + anOffset.

	y := y + anOffset.

	^ self

    ].

    "this is the general (& clean) code ..."

    offsetPoint := anOffset asPoint.

    x := x + anOffset x.

    y := y + anOffset y

! !

!Point methodsFor:'queries'!

isPoint

    "return true, if the receiver is some kind of point"

    ^ true

! !

!Point methodsFor:'misc'!

dist:aPoint 

    "return the distance between aPoint and the receiver."

    ^ (aPoint - self) r

!

dotProduct:aPoint 

    "return a number that is the dot product of the receiver and

     the argument, aPoint.  That is, the two points are

     multiplied and the coordinates of the result summed."