"

 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.

"

'From Smalltalk/X, Version:2.10.5 on 23-may-1995 at 7:19:52 am'!

ArithmeticValue subclass:#Point

	 instanceVariableNames:'x y'

	 classVariableNames:'PointZero PointOne'

	 poolDictionaries:''

	 category:'Graphics-Geometry'

!

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 isNil ifTrue:[

	PointZero := 0 @ 0.

	PointOne  := 1 @ 1

    ]

! !

!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 (_CanDoQuickNew(sizeof(struct __point))) {

	if (self == Point) {

	    OBJ newPoint;

	    int spc;

	    _qCheckedAlignedNew(newPoint, sizeof(struct __point));

	    _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

!

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:nil.

    newX notNil ifTrue:[

	(aStream skipSeparators == $@) ifTrue:[

	    aStream next.

	    newY := Number readFrom:aStream 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]

    "  

! !

!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 methodsFor:'misc'!

rounded

    "return a new point with my coordinates rounded to the next integer

     coordinated (use for gridding) or the receiver of already rounded."

    (x isInteger and:[y isInteger]) ifTrue:[^ self].

    ^ (x rounded) @ (y rounded)

!

abs

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

    ^ (x abs) @ (y abs)

!

truncated

    "return a new point with my coordinates truncated as integer or the

     receiver, if already truncated."

    (x isInteger and:[y isInteger]) ifTrue:[^ self].

    ^ (x truncated) @ (y truncated)

!

quadrantContaining:aPoint

    "return the number of the quadrant containing aPoint placing  

     the receiver at the origin, where the quadrants are numbered as  

     follows:

	   ^    2  |  3

	   Y    ------

		1  |  0

		X >

     This can be used for polygon operations (see Foley for examples).

    "

     aPoint x > x ifTrue:[

	 aPoint y >= y ifTrue:[^ 3].

	 ^ 0

     ].

     aPoint y >= y ifTrue: [^ 2].     

     ^ 1

     "

      (10 @ 10) quadrantContaining:(15 @ 15)

      (10 @ 10) quadrantContaining:(5 @ 5)    

      (10 @ 10) quadrantContaining:(5 @ 15)   

      (10 @ 10) quadrantContaining:(15 @ 5)  

     "

!

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

    "

     (0@0) quadrant   

     (1@1) quadrant    

     (-1@1) quadrant    

     (-1@-1) quadrant 

     (1@-1) quadrant   

    "

! !

!Point methodsFor:'converting'!

extent:aPoint

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

    ^ Rectangle origin:self extent:aPoint

!

asPoint

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

    ^ self

!

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      

    "

!

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      

    "

!

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      

    "

!

corner:aPoint

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

    ^ Rectangle origin:self corner:aPoint

!

asRectangle

    "return a zero-width rectangle consisting of origin 

     and corner being the receiver"

    ^ self corner:self

    "

     (0@10) asRectangle             

    "

!

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:'transformations'!

* 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 isMemberOf:SmallInteger) ifTrue:[

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

    ].

    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 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 isMemberOf:SmallInteger) ifTrue:[

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

    ].

    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)

!

- 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 isMemberOf:SmallInteger) ifTrue:[

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

    ].

    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)

!

negated

    "return a new point with my coordinates negated 

     i.e. the receiver mirrored at the origin"

    ^ (x negated) @ (y negated)

!

reciprocal

    "return a new point where the coordinates are

     the reciproce of mine"

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

!

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:'comparing'!

= 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