"

 COPYRIGHT (c) 1995 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.

"

Layout subclass:#LayoutOrigin

	instanceVariableNames:'leftFraction topFraction leftOffset topOffset'

	classVariableNames:''

	poolDictionaries:''

	category:'Graphics-Geometry'

!

!LayoutOrigin class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1995 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

"

    This class is provided to make porting of existing ST-80 applications

    easier. Instances can be used to control the geometry of a subview, within

    its superview. It provides the same functionality as a relative origin

    combined with insets.

    A layoutOrigin controls the origin of a subcomponent, given a fractional

    component and an offset component.

    Notice: 

        this class was implemented using protocol information

        from alpha testers - it may not be complete or compatible to

        the corresponding ST-80 class. 

        If you encounter any incompatibilities, please forward a note 

        describing the incompatibility verbal (i.e. no code) to the ST/X team.

    [author:]

        Claus Gittinger

    [see also:]

        View

        LayoutFrame AlignmentOrigin Layout 

        Rectangle Point

"

!

examples

"

    Although the examples below use a button as component,

    they work of course with any type of subview ....

    using a LayoutOrigin, to arrange for

    the TOPLEFT of a component be positions

    at the center (i.e. buttons origin at:0.5 @ 0.5):

                                                                        [exBegin]

        |top button|

        top := StandardSystemView new.

        top extent:300@300.

        button := Button label:'component'.

        top add:button in:(LayoutOrigin new

                                leftFraction:0.5;

                                topFraction:0.5).

        top open

                                                                        [exEnd]

    like above, but adds an additional offset:

    (i.e. center of button at:0.5 @ 0.5 OFFSET by 10 @ 20):

                                                                        [exBegin]

        |top button|

        top := StandardSystemView new.

        top extent:300@300.

        button := Button label:'component'.

        top add:button in:(LayoutOrigin new

                                leftFraction:0.5;

                                topFraction:0.5;

                                leftOffset:10;

                                topOffset:20).

        top open

                                                                        [exEnd]

"

! !

!LayoutOrigin class methodsFor:'instance creation'!

fractionalFromPoint:aPoint

    "given a point, create a layoutOrigin representing the same 

     relative origin."

    ^ (self new) leftFraction:aPoint x topFraction:aPoint y

    "

     LayoutOrigin fractionalFromPoint:0.5@0.5

    "

!

fromPoint:aPoint

    "return a new LayoutOrigin from  aPoint.

     If the coordinates are between 0 and 1, take

     them as fractional parts (relative to superview).

     Otherwise, treat them as absolute offsets."

    |x y layout|

    x := aPoint x.

    y := aPoint y.

    layout := self new.

    ((x between:0 and:1)

    and:[y between:0 and:1]) ifTrue:[

	layout leftFraction:x topFraction:y

    ] ifFalse:[

	layout leftOffset:x topOffset:y

    ].

    ^ layout

    "

     LayoutOrigin fromPoint:100@100

     LayoutOrigin fromPoint:0.5@0.5

     LayoutOrigin fromPoint:0.5@100

    "

!

offsetFromPoint:aPoint

    "given a point, create a layoutOrigin representing the same 

     absolute (pixel) origin."

    ^ self new leftOffset:aPoint x topOffset:aPoint y

    "

     LayoutOrigin offsetFromPoint:100@100

    "

! !

!LayoutOrigin methodsFor:'accessing'!

leftFraction

    "return leftFraction"

    ^ leftFraction

!

leftFraction:something

    "set leftFraction"

    leftFraction := something.

!

leftFraction:something offset:o

    "set leftFraction and offset"

    leftFraction := something.

    leftOffset := o

!

leftFraction:newLeft topFraction:newTop 

    "set leftFraction and topFraction"

    leftFraction := newLeft.

    topFraction := newTop.

!

leftOffset

    "return leftOffset"

    ^ leftOffset

!

leftOffset:something

    "set leftOffset"

    leftOffset := something.

!

leftOffset:newLeft topOffset:newTop 

    "set leftOffset and topOffset"

    leftOffset := newLeft.

    topOffset := newTop.

!

topFraction

    "return topFraction"

    ^ topFraction

!

topFraction:something

    "set topFraction"

    topFraction := something.

!

topFraction:something offset:o

    "set topFraction and offset"

    topFraction := something.

    topOffset := o

!

topOffset

    "return topOffset"

    ^ topOffset

!

topOffset:something

    "set topOffset"

    topOffset := something.

! !

!LayoutOrigin methodsFor:'converting'!

fromLiteralArrayEncoding:encoding

    "read my values from an encoding.

     The encoding is supposed to be of the form: 

	(#LayoutOrigin orgOffsX relOrgX orgOffsY relOrgY)

     This is the reverse operation to #literalArrayEncoding."

    leftOffset := encoding at:2.

    leftFraction := encoding at:3.

    topOffset := encoding at:4.

    topFraction := encoding at:5.

    "

      LayoutOrigin new fromLiteralArrayEncoding:#(#LayoutOrigin 70 0 2 0)

    "

!

literalArrayEncoding

    "encode myself as an array, from which a copy of the receiver

     can be reconstructed with #decodeAsLiteralArray.

     The encoding is: 

        (#LayoutOrigin orgOffsX relOrgX orgOffsY relOrgY)

    "

    ^ Array

        with:self class name asSymbol

        with:leftOffset

        with:leftFraction

        with:topOffset

        with:topFraction

    "

      LayoutOrigin new fromLiteralArrayEncoding:#(#LayoutOrigin 70 0 2 0)

      (LayoutOrigin new leftOffset:10; leftFraction:0.2;

                       topOffset:20; topFraction:0.4) literalArrayEncoding 

    "

    "Modified: 1.9.1995 / 02:43:48 / claus"

    "Modified: 22.4.1996 / 13:00:21 / cg"

! !

!LayoutOrigin methodsFor:'initialization'!

initialize

    leftOffset := topOffset := 0.

    leftFraction := topFraction := 0.

! !

!LayoutOrigin methodsFor:'printing & storing'!

displayString

    ^ (self class name) , '(' 

	, 'l: ' , leftFraction displayString

	, '+' , leftOffset displayString

	, ' t: ' , topFraction displayString

	, '+' , topOffset displayString

	, ')'

! !

!LayoutOrigin methodsFor:'queries'!

origin

    ^ leftFraction asFloat @ topFraction asFloat

!

rectangleRelativeTo:superRectangle preferred:prefRect

    "compute the rectangle represented by the receiver,

     given the superViews rectangle and the views preferredExtent."

    |x y|

    leftOffset isNil ifTrue:[

        x := 0

    ] ifFalse:[

        x := leftOffset

    ].

    topOffset isNil ifTrue:[

        y := 0

    ] ifFalse:[

        y := topOffset

    ].

    leftFraction notNil ifTrue:[

        x := x + (superRectangle width * leftFraction)

    ].

    topFraction notNil ifTrue:[

        y := y + (superRectangle height * topFraction)

    ].

    "

     |superRect lO|

     superRect := 0@0 corner:100@100.

     lO := (LayoutOrigin new).

     lO leftFraction:0.5;

        topFraction:0.5.

     lO rectangleRelativeTo:superRect preferred:(0@0 corner:30@30)

    "

! !

!LayoutOrigin class methodsFor:'documentation'!

version

! !