"

 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-Geometry'

!

!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.

"

!

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 isNil ifTrue:[

	PointZero := 0 @ 0.

	PointOne  := 1 @ 1

    ]

! !

!Point class methodsFor:'instance creation'!

readFrom:aStringOrStream 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."

    |str newX newY|

    str := aStringOrStream readStream.

    newX := Number readFrom:str onError:nil.

    newX notNil ifTrue:[

	(str skipSeparators == $@) ifTrue:[

	    str  next.

	    newY := Number readFrom:str onError:nil.

	    newY notNil ifTrue:[

		^ self x:newX y:newY

	    ]

	]

    ].

    ^ exceptionBlock value

    "

     Point readFrom:('1.234 @ 5.678' readStream)

     Point readFrom:('1' readStream)

     Point readFrom:('1' readStream) onError:[1@1]

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

    "

    "Modified: 16.11.1995 / 22:50:45 / cg"

!

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) {

	    OBJ newPoint;

	    int spc;

	    _InstPtr(newPoint)->o_class = Point;

	    _PointInstPtr(newPoint)->p_x = newX;

	    _PointInstPtr(newPoint)->p_y = newY;

	    if (! __bothSmallInteger(newX, newY)) {

		spc = __qSpace(newPoint);

		__STORE_SPC(newPoint, newX, spc);

		__STORE_SPC(newPoint, newY, spc);

	    }

	    RETURN ( newPoint );

	}

    }

%}

.

    ^ (self basicNew) x:newX y:newY

! !

!Point class methodsFor:'constants'!

unity

    "return the neutral element for multiplication"

    ^ PointOne

!

zero

    "return the neutral element for addition"

    ^ PointZero

! !

!Point class methodsFor:'queries'!

isBuiltInClass

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

    ^ self == Point

! !

!Point methodsFor:'accessing'!

x

    "return the x coordinate"

    ^ x

!

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

!

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

!

y

    "return the y coordinate"

    ^ y

!

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

! !

!Point methodsFor:'coercing'!

coerce:anObject

    "return aNumber converted into receivers type"

    ^ anObject asPoint

!

generality

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

    ^ 120

! !

!Point methodsFor:'comparing'!

< 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 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

!

> 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

!

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)

!

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:'converting'!

asFractionalLayout

    "return a LayoutOrigin from the receiver,

     treating the receiver coordinates as fractional parts 

     (i.e. relative to superview).

     Notice: in 10.5.x LayoutOrigin is not yet officially released."

    ^ LayoutOrigin fractionalFromPoint:self

    "

     (0@0.5) asFractionalLayout 

     (0@0.5) asLayout           

     (0@10) asLayout             

     (0@10) asOffsetLayout      

    "

!

asLayout

    "return a LayoutOrigin from the receiver.

     If the receiver coordinates are between 0 and 1, take

     them as fractional parts (relative to superview).

     Otherwise, treat them as absolute offsets.

     Notice: in 10.5.x LayoutOrigin is not yet released."

    ^ LayoutOrigin fromPoint:self

    "

     (0@0.5) asFractionalLayout 

     (0@0.5) asLayout           

     (0@10) asLayout             

     (0@10) asOffsetLayout      

    "

!

asOffsetLayout

    "return a LayoutOrigin from the receiver,

     treating the receiver coordinates as absolute offsets. 

     Notice: in 10.5.x LayoutOrigin is not yet released."

    ^ LayoutOrigin offsetFromPoint:self

    "

     (0@0.5) asFractionalLayout 

     (0@0.5) asLayout           

     (0@10) asLayout             

     (0@10) asOffsetLayout      

    "

!

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

    "

     (0@10) asRectangle             

    "

!

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

!

fromLiteralArrayEncoding:encoding

    "read my values from an encoding.

     The encoding is supposed to be of the form: (Point xValue yValue)"

    x := encoding at:2.

    y := encoding at:3.

    "

     Point new fromLiteralArrayEncoding:#(Point 10 20)

    "

!

literalArrayEncoding

    "encode myself as an array.

     The encoding is: (Point xValue yValue)"

    ^ Array

	with:#Point 

	with:x 

	with:y 

    "

     Point new fromLiteralArrayEncoding:#(Point 10 20) 

     (10@20) literalArrayEncoding  

    "

    "Modified: 1.9.1995 / 02:18:29 / claus"

!

rectangleRelativeTo:aRectangle preferred:prefRect

    "compute a displayRectangle, treating the receiver like a

     layoutorigin. This allows point to be used interchangable with

     LayoutOrigins."

    ^ (self asLayout) rectangleRelativeTo:aRectangle preferred:prefRect

    "

     consider the case, where a view has a preferred extent of 50@50

     and is to be positioned in its superview which has size 100@100.

     For absolute origin:

	 (10@20) rectangleRelativeTo:(0@0 corner:100@100) preferred:(0@0 corner:50@50) 

     for relative origin:

	 (0.5@0.5) rectangleRelativeTo:(0@0 corner:100@100) preferred:(0@0 corner:50@50) 

    "

! !

!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:'misc'!

abs

    "return a new point with my coordinates taken from the absolute values."

    ^ (x abs) @ (y abs)

!

quadrant

    "return the number of the quadrant containing the receiver.

     quadrants are named as follows:

	   ^    2  |  3

	   Y    ------

		1  |  0

		X >

     Q: what is to be returned if any coordinate is 0 ?

    "

    ^ 0@0 quadrantContaining:self

    "